CEMV3.1R1pdf

CEMV3.1R1pdf
Common Methodology
for Information Technology
Security Evaluation
Evaluation methodology
September 2006
Version 3.1
Revision 1
CCMB-2006-09-004
Foreword
This version of the Common Methodology for Information Technology Security Evaluation
(CEM v3.1) is the first major revision since being published as CEM v2.3 in 2005.
CEM v3.1 aims to: eliminate redundant evaluation activities; reduce/eliminate activities that
contribute little to the final assurance of a product; clarify CEM terminology to reduce
misunderstanding; restructure and refocus the evaluation activities to those areas where
security assurance is gained; and add new CEM requirements if needed.
Trademarks:
−
UNIX is a registered trademark of The Open Group in the United States and other
countries
−
Windows is a registered trademark of Microsoft Corporation in the United States
and other countries
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Legal Notice:
The governmental organisations listed below contributed to the development of this version
of the Common Methodology for Information Technology Security Evaluation. As the joint
holders of the copyright in the Common Methodology for Information Technology Security
Evaluation, version 3.1 (called “CEM 3.1”), they hereby grant non-exclusive license to
ISO/IEC to use CEM 3.1 in the continued development/maintenance of the ISO/IEC 18045
international standard. However, these governmental organisations retain the right to use,
copy, distribute, translate or modify CEM 3.1 as they see fit.
Australia/New Zealand:
Canada:
France:
Germany:
Japan:
Netherlands:
Spain:
United Kingdom:
United States:
September 2006
The Defence Signals Directorate and the
Government Communications Security Bureau respectively;
Communications Security Establishment;
Direction Centrale de la Sécurité des Systèmes d'Information;
Bundesamt für Sicherheit in der Informationstechnik;
Information Technology Promotion Agency
Netherlands National Communications Security Agency;
Ministerio de Administraciones Públicas and
Centro Criptológico Nacional;
Communications-Electronics Security Group;
The National Security Agency and the
National Institute of Standards and Technology.
Version 3.1
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Table of contents
Table of Contents
1
INTRODUCTION............................................................................................. 12
2
SCOPE ........................................................................................................... 13
3
NORMATIVE REFERENCES ......................................................................... 14
4
TERMS AND DEFINITIONS ........................................................................... 15
5
SYMBOLS AND ABBREVIATED TERMS ..................................................... 17
6
OVERVIEW..................................................................................................... 18
6.1
7
Organisation of the CEM.................................................................................................................. 18
DOCUMENT CONVENTIONS ........................................................................ 19
7.1
Terminology....................................................................................................................................... 19
7.2
Verb usage.......................................................................................................................................... 19
7.3
General evaluation guidance ............................................................................................................ 19
7.4
Relationship between CC and CEM structures.............................................................................. 19
8
8.1
EVALUATION PROCESS AND RELATED TASKS....................................... 21
Introduction ....................................................................................................................................... 21
8.2
Evaluation process overview ............................................................................................................ 21
8.2.1
Objectives....................................................................................................................................... 21
8.2.2
Responsibilities of the roles............................................................................................................ 21
8.2.3
Relationship of roles....................................................................................................................... 22
8.2.4
General evaluation model............................................................................................................... 22
8.2.5
Evaluator verdicts........................................................................................................................... 23
8.3
Evaluation input task ........................................................................................................................ 25
8.3.1
Objectives....................................................................................................................................... 25
8.3.2
Application notes............................................................................................................................ 25
8.3.3
Management of evaluation evidence sub-task ................................................................................ 26
8.4
Evaluation sub-activities................................................................................................................... 27
8.5
Evaluation output task...................................................................................................................... 27
8.5.1
Objectives....................................................................................................................................... 27
8.5.2
Management of evaluation outputs................................................................................................. 27
8.5.3
Application notes............................................................................................................................ 28
8.5.4
Write OR sub-task .......................................................................................................................... 28
8.5.5
Write ETR sub-task ........................................................................................................................ 28
9
CLASS APE: PROTECTION PROFILE EVALUATION ................................. 35
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9.1
Introduction ....................................................................................................................................... 35
9.2
Application notes ............................................................................................................................... 35
9.2.1
Re-using the evaluation results of certified PPs.............................................................................. 35
9.3
PP introduction (APE_INT) ............................................................................................................. 36
9.3.1
Evaluation of sub-activity (APE_INT.1) ........................................................................................ 36
9.4
Conformance claims (APE_CCL) .................................................................................................... 38
9.4.1
Evaluation of sub-activity (APE_CCL.1) ....................................................................................... 38
9.5
Security problem definition (APE_SPD) ......................................................................................... 43
9.5.1
Evaluation of sub-activity (APE_SPD.1) ....................................................................................... 43
9.6
Security objectives (APE_OBJ)........................................................................................................ 45
9.6.1
Evaluation of sub-activity (APE_OBJ.1)........................................................................................ 45
9.6.2
Evaluation of sub-activity (APE_OBJ.2)........................................................................................ 45
9.7
Extended components definition (APE_ECD) ................................................................................ 49
9.7.1
Evaluation of sub-activity (APE_ECD.1)....................................................................................... 49
9.8
Security requirements (APE_REQ)................................................................................................. 54
9.8.1
Evaluation of sub-activity (APE_REQ.1)....................................................................................... 54
9.8.2
Evaluation of sub-activity (APE_REQ.2)....................................................................................... 57
10
CLASS ASE: SECURITY TARGET EVALUATION.................................... 63
10.1
Introduction ....................................................................................................................................... 63
10.2
Application notes ............................................................................................................................... 63
10.2.1
Re-using the evaluation results of certified PPs......................................................................... 63
10.3
ST introduction (ASE_INT) ............................................................................................................. 64
10.3.1
Evaluation of sub-activity (ASE_INT.1) ................................................................................... 64
10.4
Conformance claims (ASE_CCL) .................................................................................................... 67
10.4.1
Evaluation of sub-activity (ASE_CCL.1) .................................................................................. 67
10.5
Security problem definition (ASE_SPD) ......................................................................................... 75
10.5.1
Evaluation of sub-activity (ASE_SPD.1)................................................................................... 75
10.6
Security objectives (ASE_OBJ)........................................................................................................ 77
10.6.1
Evaluation of sub-activity (ASE_OBJ.1)................................................................................... 77
10.6.2
Evaluation of sub-activity (ASE_OBJ.2)................................................................................... 77
10.7
Extended components definition (ASE_ECD) ................................................................................ 81
10.7.1
Evaluation of sub-activity (ASE_ECD.1) .................................................................................. 81
10.8
Security requirements (ASE_REQ) ................................................................................................. 86
10.8.1
Evaluation of sub-activity (ASE_REQ.1) .................................................................................. 86
10.8.2
Evaluation of sub-activity (ASE_REQ.2) .................................................................................. 89
10.9
TOE summary specification (ASE_TSS)......................................................................................... 95
10.9.1
Evaluation of sub-activity (ASE_TSS.1) ................................................................................... 95
10.9.2
Evaluation of sub-activity (ASE_TSS.2) ................................................................................... 95
11
CLASS ADV: DEVELOPMENT .................................................................. 98
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11.1
Introduction ....................................................................................................................................... 98
11.2
Application notes ............................................................................................................................... 98
11.3
Security Architecture (ADV_ARC) ............................................................................................... 100
11.3.1
Evaluation of sub-activity (ADV_ARC.1)............................................................................... 100
11.4
Functional specification (ADV_FSP)............................................................................................. 106
11.4.1
Evaluation of sub-activity (ADV_FSP.1) ................................................................................ 106
11.4.2
Evaluation of sub-activity (ADV_FSP.2) ................................................................................ 110
11.4.3
Evaluation of sub-activity (ADV_FSP.3) ................................................................................ 115
11.4.4
Evaluation of sub-activity (ADV_FSP.4) ................................................................................ 122
11.4.5
Evaluation of sub-activity (ADV_FSP.5) ................................................................................ 128
11.4.6
Evaluation of sub-activity (ADV_FSP.6) ................................................................................ 135
11.5
Implementation representation (ADV_IMP)................................................................................ 136
11.5.1
Evaluation of sub-activity (ADV_IMP.1)................................................................................ 136
11.5.2
Evaluation of sub-activity (ADV_IMP.2)................................................................................ 138
11.6
TSF internals (ADV_INT) .............................................................................................................. 139
11.6.1
Evaluation of sub-activity (ADV_INT.1) ................................................................................ 139
11.6.2
Evaluation of sub-activity (ADV_INT.2) ................................................................................ 142
11.6.3
Evaluation of sub-activity (ADV_INT.3) ................................................................................ 144
11.7
Security policy modelling (ADV_SPM) ......................................................................................... 145
11.7.1
Evaluation of sub-activity (ADV_SPM.1)............................................................................... 145
11.8
TOE design (ADV_TDS)................................................................................................................. 146
11.8.1
Evaluation of sub-activity (ADV_TDS.1) ............................................................................... 146
11.8.2
Evaluation of sub-activity (ADV_TDS.2) ............................................................................... 150
11.8.3
Evaluation of sub-activity (ADV_TDS.3) ............................................................................... 156
11.8.4
Evaluation of sub-activity (ADV_TDS.4) ............................................................................... 168
11.8.5
Evaluation of sub-activity (ADV_TDS.5) ............................................................................... 179
11.8.6
Evaluation of sub-activity (ADV_TDS.6) ............................................................................... 179
12
CLASS AGD: GUIDANCE DOCUMENTS ................................................ 180
12.1
Introduction ..................................................................................................................................... 180
12.2
Application notes ............................................................................................................................. 180
12.3
Operational user guidance (AGD_OPE) ....................................................................................... 181
12.3.1
Evaluation of sub-activity (AGD_OPE.1) ............................................................................... 181
12.4
Preparative procedures (AGD_PRE) ............................................................................................ 185
12.4.1
Evaluation of sub-activity (AGD_PRE.1) ............................................................................... 185
13
CLASS ALC: LIFE-CYCLE SUPPORT .................................................... 188
13.1
Introduction ..................................................................................................................................... 188
13.2
CM capabilities (ALC_CMC) ........................................................................................................ 189
13.2.1
Evaluation of sub-activity (ALC_CMC.1)............................................................................... 189
13.2.2
Evaluation of sub-activity (ALC_CMC.2)............................................................................... 190
13.2.3
Evaluation of sub-activity (ALC_CMC.3)............................................................................... 192
13.2.4
Evaluation of sub-activity (ALC_CMC.4)............................................................................... 196
13.2.5
Evaluation of sub-activity (ALC_CMC.5)............................................................................... 203
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13.3
CM scope (ALC_CMS) ................................................................................................................... 212
13.3.1
Evaluation of sub-activity (ALC_CMS.1) ............................................................................... 212
13.3.2
Evaluation of sub-activity (ALC_CMS.2) ............................................................................... 212
13.3.3
Evaluation of sub-activity (ALC_CMS.3) ............................................................................... 213
13.3.4
Evaluation of sub-activity (ALC_CMS.4) ............................................................................... 214
13.3.5
Evaluation of sub-activity (ALC_CMS.5) ............................................................................... 215
13.4
Delivery (ALC_DEL) ...................................................................................................................... 218
13.4.1
Evaluation of sub-activity (ALC_DEL.1)................................................................................ 218
13.5
Development security (ALC_DVS) ................................................................................................ 220
13.5.1
Evaluation of sub-activity (ALC_DVS.1)................................................................................ 220
13.5.2
Evaluation of sub-activity (ALC_DVS.2)................................................................................ 223
13.6
Flaw remediation (ALC_FLR) ....................................................................................................... 228
13.6.1
Evaluation of sub-activity (ALC_FLR.1) ................................................................................ 228
13.6.2
Evaluation of sub-activity (ALC_FLR.2) ................................................................................ 230
13.6.3
Evaluation of sub-activity (ALC_FLR.3) ................................................................................ 234
13.7
Life-cycle definition (ALC_LCD)................................................................................................... 241
13.7.1
Evaluation of sub-activity (ALC_LCD.1)................................................................................ 241
13.7.2
Evaluation of sub-activity (ALC_LCD.2)................................................................................ 242
13.8
Tools and techniques (ALC_TAT)................................................................................................. 245
13.8.1
Evaluation of sub-activity (ALC_TAT.1)................................................................................ 245
13.8.2
Evaluation of sub-activity (ALC_TAT.2)................................................................................ 247
13.8.3
Evaluation of sub-activity (ALC_TAT.3)................................................................................ 250
14
CLASS ATE: TESTS ................................................................................ 254
14.1
Introduction ..................................................................................................................................... 254
14.2
Application notes ............................................................................................................................. 254
14.2.1
Understanding the expected behaviour of the TOE ................................................................. 255
14.2.2
Testing vs. alternate approaches to verify the expected behaviour of functionality ................ 255
14.2.3
Verifying the adequacy of tests................................................................................................ 256
14.3
Coverage (ATE_COV) .................................................................................................................... 257
14.3.1
Evaluation of sub-activity (ATE_COV.1) ............................................................................... 257
14.3.2
Evaluation of sub-activity (ATE_COV.2) ............................................................................... 258
14.3.3
Evaluation of sub-activity (ATE_COV.3) ............................................................................... 259
14.4
Depth (ATE_DPT)........................................................................................................................... 260
14.4.1
Evaluation of sub-activity (ATE_DPT.1) ................................................................................ 260
14.4.2
Evaluation of sub-activity (ATE_DPT.2) ................................................................................ 262
14.4.3
Evaluation of sub-activity (ATE_DPT.3) ................................................................................ 265
14.4.4
Evaluation of sub-activity (ATE_DPT.4) ................................................................................ 267
14.5
Functional tests (ATE_FUN) .......................................................................................................... 268
14.5.1
Evaluation of sub-activity (ATE_FUN.1)................................................................................ 268
14.5.2
Evaluation of sub-activity (ATE_FUN.2)................................................................................ 271
14.6
Independent testing (ATE_IND) .................................................................................................... 272
14.6.1
Evaluation of sub-activity (ATE_IND.1)................................................................................. 272
14.6.2
Evaluation of sub-activity (ATE_IND.2)................................................................................. 277
14.6.3
Evaluation of sub-activity (ATE_IND.3)................................................................................. 283
15
CLASS AVA: VULNERABILITY ASSESSMENT ..................................... 284
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15.1
Introduction ..................................................................................................................................... 284
15.2
Vulnerability analysis (AVA_VAN)............................................................................................... 285
15.2.1
Evaluation of sub-activity (AVA_VAN.1) .............................................................................. 285
15.2.2
Evaluation of sub-activity (AVA_VAN.2) .............................................................................. 291
15.2.3
Evaluation of sub-activity (AVA_VAN.3) .............................................................................. 299
15.2.4
Evaluation of sub-activity (AVA_VAN.4) .............................................................................. 310
15.2.5
Evaluation of sub-activity (AVA_VAN.5) .............................................................................. 319
16
CLASS ACO: COMPOSITION.................................................................. 320
16.1
Introduction ..................................................................................................................................... 320
16.2
Application notes ............................................................................................................................. 320
16.3
Composition rationale (ACO_COR).............................................................................................. 322
16.3.1
Evaluation of sub-activity (ACO_COR.1)............................................................................... 322
16.4
Development evidence (ACO_DEV) .............................................................................................. 330
16.4.1
Evaluation of sub-activity (ACO_DEV.1)............................................................................... 330
16.4.2
Evaluation of sub-activity (ACO_DEV.2)............................................................................... 331
16.4.3
Evaluation of sub-activity (ACO_DEV.3)............................................................................... 333
16.5
Reliance of dependent component (ACO_REL)........................................................................... 337
16.5.1
Evaluation of sub-activity (ACO_REL.1) ............................................................................... 337
16.5.2
Evaluation of sub-activity (ACO_REL.2) ............................................................................... 339
16.6
Composed TOE testing (ACO_CTT)............................................................................................. 343
16.6.1
Evaluation of sub-activity (ACO_CTT.1) ............................................................................... 343
16.6.2
Evaluation of sub-activity (ACO_CTT.2) ............................................................................... 346
16.7
Composition vulnerability analysis (ACO_VUL) ......................................................................... 351
16.7.1
Evaluation of sub-activity (ACO_VUL.1)............................................................................... 351
16.7.2
Evaluation of sub-activity (ACO_VUL.2)............................................................................... 354
16.7.3
Evaluation of sub-activity (ACO_VUL.3)............................................................................... 359
A
GENERAL EVALUATION GUIDANCE ........................................................ 364
A.1
Objectives......................................................................................................................................... 364
A.2
Sampling........................................................................................................................................... 364
A.3
Dependencies.................................................................................................................................... 366
A.3.1 Dependencies between activities .................................................................................................. 367
A.3.2 Dependencies between sub-activities ........................................................................................... 367
A.3.3 Dependencies between actions ..................................................................................................... 367
A.4
Site Visits.......................................................................................................................................... 368
A.4.1 Introduction .................................................................................................................................. 368
A.4.2 General Approach......................................................................................................................... 368
A.4.3 Orientation Guide for the Preparation of the Check List .............................................................. 369
A.4.4 Example of a checklist.................................................................................................................. 371
A.5
B
Scheme Responsibilities .................................................................................................................. 374
VULNERABILITY ASSESSMENT (AVA) ..................................................... 377
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B.1
What is Vulnerability Analysis....................................................................................................... 377
B.2
Evaluator construction of a Vulnerability Analysis ..................................................................... 378
B.2.1 Generic vulnerability guidance..................................................................................................... 378
B.2.2 Identification of Potential Vulnerabilities..................................................................................... 388
B.3
When attack potential is used......................................................................................................... 392
B.3.1 Developer...................................................................................................................................... 392
B.3.2 Evaluator....................................................................................................................................... 392
B.4
Calculating attack potential............................................................................................................ 394
B.4.1 Application of attack potential...................................................................................................... 394
B.4.2 Characterising attack potential...................................................................................................... 395
B.5
Example calculation for direct attack............................................................................................ 404
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List of figures
List of figures
Figure 1 - Mapping of the CC and CEM structures.............................................................. 20
Figure 2 - Generic evaluation model .................................................................................... 23
Figure 3 - Example of the verdict assignment rule ............................................................... 24
Figure 4 - ETR information content for a PP evaluation ...................................................... 29
Figure 5 - ETR information content for a TOE evaluation................................................... 32
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List of tables
List of tables
Table 1 Example of a checklist at EAL 4 (extract) ............................................................373
Table 2 Vulnerability testing and attack potential...............................................................393
Table 3 Calculation of attack potential................................................................................401
Table 4 Rating of vulnerabilities and TOE resistance.........................................................403
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Introduction
1
Introduction
1
The target audience for the Common Methodology for Information
Technology Security Evaluation (CEM) is primarily evaluators applying the
CC and certifiers confirming evaluator actions; evaluation sponsors,
developers, PP/ST authors and other parties interested in IT security may be
a secondary audience.
2
The CEM recognises that not all questions concerning IT security evaluation
will be answered herein and that further interpretations will be needed.
Individual schemes will determine how to handle such interpretations,
although these may be subject to mutual recognition agreements. A list of
methodology-related activities that may be handled by individual schemes
can be found in Annex A.
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Scope
2
Scope
3
The Common Methodology for Information Technology Security Evaluation
(CEM) is a companion document to the Common Criteria for Information
Technology Security Evaluation (CC). The CEM describes the minimum
actions to be performed by an evaluator in order to conduct a CC evaluation,
using the criteria and evaluation evidence defined in the CC.
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Normative references
3
Normative references
4
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including
any amendments) applies.
CC
Common Criteria for Information Technology Security Evaluation, Version
3.1, revision 1, September 2006.
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Terms and definitions
4
Terms and definitions
5
For the purposes of this document, the following terms and definitions apply.
6
Terms which are presented in bold-faced type are themselves defined in this
Section.
7
action ⎯ evaluator action element of the CC Part 3. These actions are either
explicitly stated as evaluator actions or implicitly derived from developer
actions (implied evaluator actions) within the CC Part 3 assurance
components.
8
activity ⎯ the application of an assurance class of the CC Part 3.
9
check ⎯ to generate a verdict by a simple comparison. Evaluator expertise
is not required. The statement that uses this verb describes what is mapped.
10
evaluation deliverable ⎯ any resource required from the sponsor or
developer by the evaluator or overseer to perform one or more evaluation or
evaluation oversight activities.
11
evaluation evidence ⎯ a tangible evaluation deliverable.
12
evaluation technical report ⎯ a report that documents the overall verdict
and its justification, produced by the evaluator and submitted to an overseer.
13
examine ⎯ to generate a verdict by analysis using evaluator expertise. The
statement that uses this verb identifies what is analysed and the properties for
which it is analysed.
14
interpretation ⎯ a clarification or amplification of a CC, CEM or scheme
requirement.
15
methodology ⎯ the system of principles, procedures and processes applied
to IT security evaluations.
16
observation report ⎯ a report written by the evaluator requesting a
clarification or identifying a problem during the evaluation.
17
overall verdict ⎯ a pass or fail statement issued by an evaluator with
respect to the result of an evaluation.
18
19
oversight verdict ⎯ a statement issued by an overseer confirming or
rejecting an overall verdict based on the results of evaluation oversight
activities.
record ⎯ to retain a written description of procedures, events, observations,
insights and results in sufficient detail to enable the work performed during
the evaluation to be reconstructed at a later time.
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Terms and definitions
20
21
22
23
24
25
report ⎯ to include evaluation results and supporting material in the
Evaluation Technical Report or an Observation Report.
scheme ⎯ set of rules, established by an evaluation authority, defining the
evaluation environment, including criteria and methodology required to
conduct IT security evaluations.
sub-activity ⎯ the application of an assurance component of the CC Part 3.
Assurance families are not explicitly addressed in the CEM because
evaluations are conducted on a single assurance component from an
assurance family.
tracing ⎯ a simple directional relation between two sets of entities, which
shows which entities in the first set correspond to which entities in the
second.
verdict ⎯ a pass, fail or inconclusive statement issued by an evaluator with
respect to a CC evaluator action element, assurance component, or class.
Also see overall verdict.
work unit ⎯ the most granular level of evaluation work. Each CEM action
comprises one or more work units, which are grouped within the CEM action
by CC content and presentation of evidence or developer action element. The
work units are presented in the CEM in the same order as the CC elements
from which they are derived. Work units are identified in the left margin by a
symbol such as ALC_TAT.1-2. In this symbol, the string ALC_TAT.1
indicates the CC component (i.e. the CEM sub-activity), and the final digit
(2) indicates that this is the second work unit in the ALC_TAT.1 subactivity.
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Symbols and abbreviated terms
5
Symbols and abbreviated terms
CEM
Common Methodology for Information Technology
Security Evaluation
ETR
Evaluation Technical Report
OR
Observation Report
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Overview
6
Overview
6.1
Organisation of the CEM
26
Chapter 7 defines the conventions used in the CEM.
27
Chapter 8 describes general evaluation tasks with no verdicts associated with
them as they do not map to CC evaluator action elements.
28
Chapter 9 addresses the work necessary for reaching an evaluation result on
a PP.
29
Chapters 10 to 16 define the evaluation activities, organised by Assurance
Classes.
30
Annex A covers the basic evaluation techniques used to provide technical
evidence of evaluation results.
31
Annex B provides an explanation of the Vulnerability Analysis criteria and
examples of their application
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Document Conventions
7
Document Conventions
7.1
Terminology
32
Unlike the CC, where each element maintains the last digit of its identifying
symbol for all components within the family, the CEM may introduce new
work units when a CC evaluator action element changes from sub-activity to
sub-activity; as a result, the last digit of the work unit's identifying symbol
may change although the work unit remains unchanged.
33
Any methodology-specific evaluation work required that is not derived
directly from CC requirements is termed task or sub-task.
7.2
Verb usage
34
All work unit and sub-task verbs are preceded by the auxiliary verb shall and
by presenting both the verb and the shall in bold italic type face. The
auxiliary verb shall is used only when the provided text is mandatory and
therefore only within the work units and sub-tasks. The work units and subtasks contain mandatory activities that the evaluator must perform in order to
assign verdicts.
35
Guidance text accompanying work units and sub-tasks gives further
explanation on how to apply the CC words in an evaluation. The verb usage
is in accordance with ISO definitions for these verbs. The auxiliary verb
should is used when the described method is strongly preferred. All other
auxiliary verbs, including may, are used where the described method(s) is
allowed but is neither recommended nor strongly preferred; it is merely
explanation.
36
The verbs check, examine, report and record are used with a precise meaning
within this part of the CEM and the Chapter 4 should be referenced for their
definitions.
7.3
General evaluation guidance
37
Material that has applicability to more than one sub-activity is collected in
one place. Guidance whose applicability is widespread (across activities and
EALs) has been collected into Annex A. Guidance that pertains to multiple
sub-activities within a single activity has been provided in the introduction to
that activity. If guidance pertains to only a single sub-activity, it is presented
within that sub-activity.
7.4
Relationship between CC and CEM structures
38
There are direct relationships between the CC structure (i.e. class, family,
component and element) and the structure of the CEM. Figure 1 illustrates
the correspondence between the CC constructs of class, family and evaluator
action elements and CEM activities, sub-activities and actions. However,
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Document Conventions
several CEM work units may result from the requirements noted in CC
developer action and content and presentation elements.
Figure 1 - Mapping of the CC and CEM structures
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Evaluation process and related tasks
8
Evaluation process and related tasks
8.1
Introduction
39
This chapter provides an overview of the evaluation process and defines the
tasks an evaluator is intended to perform when conducting an evaluation.
40
Each evaluation, whether of a PP or TOE (including ST), follows the same
process, and has four evaluator tasks in common: the input task, the output
task, the evaluation sub-activities, and the demonstration of the technical
competence to the evaluation authority task.
41
The input task and the output tasks, which are related to management of
evaluation evidence and to report generation, are entirely described in this
chapter. Each task has associated sub-tasks that apply to, and are normative
for all CC evaluations (evaluation of a PP or a TOE).
42
The evaluation sub-activities are only introduced in this chapter, and fully
described in the following chapters.
43
In contrast to the evaluation sub-activities, input and output tasks have no
verdicts associated with them as they do not map to CC evaluator action
elements; they are performed in order to ensure conformance with the
universal principles and to comply with the CEM.
44
The demonstration of the technical competence to the evaluation authority
task may be fulfilled by the evaluation authority analysis of the output tasks
results, or may include the demonstration by the evaluators of their
understanding of the inputs for the evaluation sub-activities. This task has no
associated evaluator verdict, but has an evaluator authority verdict. The
detailed criteria to pass this task are left to the discretion of the evaluation
authority, as noted in Annex A.5.
8.2
Evaluation process overview
8.2.1
Objectives
45
This section presents the general model of the methodology and identifies:
a)
roles and responsibilities of the parties involved in the evaluation
process;
b)
the general evaluation model.
8.2.2
Responsibilities of the roles
46
The general model defines the following roles: sponsor, developer, evaluator
and evaluation authority.
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47
The sponsor is responsible for requesting and supporting an evaluation. This
means that the sponsor establishes the different agreements for the evaluation
(e.g. commissioning the evaluation). Moreover, the sponsor is responsible
for ensuring that the evaluator is provided with the evaluation evidence.
48
The developer produces the TOE and is responsible for providing the
evidence required for the evaluation (e.g. training, design information), on
behalf of the sponsor.
49
The evaluator performs the evaluation tasks required in the context of an
evaluation: the evaluator receives the evaluation evidence from the developer
on behalf of the sponsor or directly from the sponsor, performs the
evaluation sub-activities and provides the results of the evaluation
assessment to the evaluation authority.
50
The evaluation authority establishes and maintains the scheme, monitors the
evaluation conducted by the evaluator, and issues certification/validation
reports as well as certificates based on the evaluation results provided by the
evaluator.
8.2.3
Relationship of roles
51
To prevent undue influence from improperly affecting an evaluation, some
separation of roles is required. This implies that the roles described above are
fulfilled by different entities, except that the roles of developer and sponsor
may be satisfied by a single entity.
52
Moreover, some evaluations (e.g. EAL1 evaluation) may not require the
developer to be involved in the project. In this case, it is the sponsor who
provides the TOE to the evaluator and who generates the evaluation
evidence.
8.2.4
General evaluation model
53
The evaluation process consists of the evaluator performing the evaluation
input task, the evaluation output task and the evaluation sub-activities. Figure
2 provides an overview of the relationship between these tasks and subactivities.
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Figure 2 - Generic evaluation model
54
The evaluation process may be preceded by a preparation phase where initial
contact is made between the sponsor and the evaluator. The work that is
performed and the involvement of the different roles during this phase may
vary. It is typically during this step that the evaluator performs a feasibility
analysis to assess the likelihood of a successful evaluation.
8.2.5
Evaluator verdicts
55
The evaluator assigns verdicts to the requirements of the CC and not to those
of the CEM. The most granular CC structure to which a verdict is assigned is
the evaluator action element (explicit or implied). A verdict is assigned to an
applicable CC evaluator action element as a result of performing the
corresponding CEM action and its constituent work units. Finally, an
evaluation result is assigned, as described in CC Part 1, Chapter 9,
Evaluation results.
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Figure 3 - Example of the verdict assignment rule
56
The CEM recognises three mutually exclusive verdict states:
a)
b)
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Conditions for a pass verdict are defined as an evaluator completion
of the CC evaluator action element and determination that the
requirements for the PP, ST or TOE under evaluation are met. The
conditions for passing the element are defined as:
1)
the constituent work units of the related CEM action, and;
2)
all evaluation evidence required for performing these work
units is coherent, that is it can be fully and completely
understood by the evaluator, and
3)
all evaluation evidence required for performing these work
units does not have any obvious internal inconsistencies or
inconsistencies with other evaluation evidence. Note that
obvious means here that the evaluator discovers this
inconsistency while performing the work units: the evaluator
should not undertake a full consistency analysis across the
entire evaluation evidence every time a work unit is
performed.
Conditions for a fail verdict are defined as an evaluator completion of
the CC evaluator action element and determination that the
requirements for the PP, ST, or TOE under evaluation are not met, or
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that the evidence is incoherent, or an obvious inconsistency in the
evaluation evidence has been found;
c)
All verdicts are initially inconclusive and remain so until either a pass
or fail verdict is assigned.
57
The overall verdict is pass if and only if all the constituent verdicts are also
pass. In the example illustrated in Figure 3, if the verdict for one evaluator
action element is fail then the verdicts for the corresponding assurance
component, assurance class, and overall verdict are also fail.
8.3
Evaluation input task
8.3.1
Objectives
58
The objective of this task is to ensure that the evaluator has available the
correct version of the evaluation evidence necessary for the evaluation and
that it is adequately protected. Otherwise, the technical accuracy of the
evaluation cannot be assured, nor can it be assured that the evaluation is
being conducted in a way to provide repeatable and reproducible results.
8.3.2
Application notes
59
The responsibility to provide all the required evaluation evidence lies with
the sponsor. However, most of the evaluation evidence is likely to be
produced and supplied by the developer, on behalf of the sponsor.
60
Since the assurance requirements apply to the entire TOE, all evaluation
evidence pertaining to all parts of the TOE is to be made available to the
evaluator. The scope and required content of such evaluation evidence is
independent of the level of control that the developer has over each of the
parts of the TOE. For example, if design is required, then the TOE design
(ADV_TDS) requirements will apply to all subsystems that are part of the
TSF. In addition, assurance requirements that call for procedures to be in
place (for example, CM capabilities (ALC_CMC) and Delivery
(ALC_DEL)) will also apply to the entire TOE (including any part produced
by another developer).
61
It is recommended that the evaluator, in conjunction with the sponsor,
produce an index to required evaluation evidence. This index may be a set of
references to the documentation. This index should contain enough
information (e.g. a brief summary of each document, or at least an explicit
title, indication of the sections of interest) to help the evaluator to find easily
the required evidence.
62
It is the information contained in the evaluation evidence that is required, not
any particular document structure. Evaluation evidence for a sub-activity
may be provided by separate documents, or a single document may satisfy
several of the input requirements of a sub-activity.
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63
The evaluator requires stable and formally-issued versions of evaluation
evidence. However, draft evaluation evidence may be provided during an
evaluation, for example, to help an evaluator make an early, informal
assessment, but is not used as the basis for verdicts. It may be helpful for the
evaluator to see draft versions of particular appropriate evaluation evidence,
such as:
a)
test documentation, to allow the evaluator to make an early
assessment of tests and test procedures;
b)
design documents, to provide the evaluator with background for
understanding the TOE design;
c)
source code or hardware drawings, to allow the evaluator to assess
the application of the developer's standards.
64
Draft evaluation evidence is more likely to be encountered where the
evaluation of a TOE is performed concurrently with its development.
However, it may also be encountered during the evaluation of an alreadydeveloped TOE where the developer has had to perform additional work to
address a problem identified by the evaluator (e.g. to correct an error in
design or implementation) or to provide evaluation evidence of security that
is not provided in the existing documentation (e.g. in the case of a TOE not
originally developed to meet the requirements of the CC).
8.3.3
Management of evaluation evidence sub-task
8.3.3.1
Configuration control
65
The evaluator shall perform configuration control of the evaluation
evidence.
66
The CC implies that the evaluator is able to identify and locate each item of
evaluation evidence after it has been received and is able to determine
whether a specific version of a document is in the evaluator's possession.
67
The evaluator shall protect the evaluation evidence from alteration or loss
while it is in the evaluator's possession.
8.3.3.2
Disposal
68
Schemes may wish to control the disposal of evaluation evidence at the
conclusion of an evaluation. The disposal of the evaluation evidence should
be achieved by one or more of:
a)
returning the evaluation evidence;
b)
archiving the evaluation evidence;
c)
destroying the evaluation evidence.
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8.3.3.3
Confidentiality
69
An evaluator may have access to sponsor and developer commerciallysensitive information (e.g. TOE design information, specialist tools), and
may have access to nationally-sensitive information during the course of an
evaluation. Schemes may wish to impose requirements for the evaluator to
maintain the confidentiality of the evaluation evidence. The sponsor and
evaluator may mutually agree to additional requirements as long as these are
consistent with the scheme.
70
Confidentiality requirements affect many aspects of evaluation work,
including the receipt, handling, storage and disposal of evaluation evidence.
8.4
Evaluation sub-activities
71
The evaluation sub-activities vary depending whether it is a PP or a TOE
evaluation. Moreover, in the case of a TOE evaluation, the sub-activities
depend upon the selected assurance requirements.
8.5
Evaluation output task
8.5.1
Objectives
72
The objective of this Section is to describe the Observation Report (OR) and
the Evaluation Technical Report (ETR). Schemes may require additional
evaluator reports such as reports on individual units of work, or may require
additional information to be contained in the OR and the ETR. The CEM
does not preclude the addition of information into these reports as the CEM
specifies only the minimum information content.
73
Consistent reporting of evaluation results facilitates the achievement of the
universal principle of repeatability and reproducibility of results. The
consistency covers the type and the amount of information reported in the
ETR and OR. ETR and OR consistency among different evaluations is the
responsibility of the overseer.
74
The evaluator performs the two following sub-tasks in order to achieve the
CEM requirements for the information content of reports:
a)
write OR sub-task (if needed in the context of the evaluation);
b)
write ETR sub-task.
8.5.2
Management of evaluation outputs
75
The evaluator delivers the ETR to the evaluation authority, as well as any
ORs as they become available. Requirements for controls on handling the
ETR and ORs are established by the scheme which may include delivery to
the sponsor or developer. The ETR and ORs may include sensitive or
proprietary information and may need to be sanitised before they are given to
the sponsor.
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8.5.3
Application notes
76
In this version of the CEM, the requirements for the provision of evaluator
evidence to support re-evaluation and re-use have not been explicitly stated.
Where information for re-evaluation or re-use is required by the sponsor, the
scheme under which the evaluation is being performed should be consulted.
8.5.4
Write OR sub-task
77
ORs provide the evaluator with a mechanism to request a clarification (e.g.
from the overseer on the application of a requirement) or to identify a
problem with an aspect of the evaluation.
78
In the case of a fail verdict, the evaluator shall provide an OR to reflect the
evaluation result. Otherwise, the evaluator may use ORs as one way of
expressing clarification needs.
79
For each OR, the evaluator shall report the following:
a)
the identifier of the PP or TOE evaluated;
b)
the evaluation task/sub-activity during which the observation was
generated;
c)
the observation;
d)
the assessment of its severity (e.g. implies a fail verdict, holds up
progress on the evaluation, requires a resolution prior to evaluation
being completed);
e)
the identification of the organisation responsible for resolving the
issue;
f)
the recommended timetable for resolution;
g)
the assessment of the impact on the evaluation of failure to resolve
the observation.
80
The intended audience of an OR and procedures for handling the report
depend on the nature of the report's content and on the scheme. Schemes may
distinguish different types of ORs or define additional types, with associated
differences in required information and distribution (e.g. evaluation ORs to
overseers and sponsors).
8.5.5
Write ETR sub-task
8.5.5.1
Objectives
81
The evaluator shall provide an ETR to present technical justification of the
verdicts.
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82
The CEM defines the ETR's minimum content requirement; however,
schemes may specify additional content and specific presentational and
structural requirements. For instance, schemes may require that certain
introductory material (e.g. disclaimers and copyright Chapters) be reported in
the ETR.
83
The reader of the ETR is assumed to be familiar with general concepts of
information security, the CC, the CEM, evaluation approaches and IT.
84
The ETR supports the evaluation authority to confirm that the evaluation was
done to the required standard, but it is anticipated that the documented results
may not provide all of the necessary information, so additional information
specifically requested by the scheme may be necessary. This aspect is
outside the scope of the CEM.
8.5.5.2
ETR for a PP Evaluation
85
This Section describes the minimum content of the ETR for a PP evaluation.
The contents of the ETR are portrayed in Figure 4; this figure may be used as
a guide when constructing the structural outline of the ETR document.
Figure 4 - ETR information content for a PP evaluation
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8.5.5.2.1
Introduction
86
The evaluator shall report evaluation scheme identifiers.
87
Evaluation scheme identifiers (e.g. logos) are the information required to
unambiguously identify the scheme responsible for the evaluation oversight.
88
The evaluator shall report ETR configuration control identifiers.
89
The ETR configuration control identifiers contain information that identifies
the ETR (e.g. name, date and version number).
90
The evaluator shall report PP configuration control identifiers.
91
PP configuration control identifiers (e.g. name, date and version number) are
required to identify what is being evaluated in order for the overseer to verify
that the verdicts have been assigned correctly by the evaluator.
92
The evaluator shall report the identity of the developer.
93
The identity of the PP developer is required to identify the party responsible
for producing the PP.
94
The evaluator shall report the identity of the sponsor.
95
The identity of the sponsor is required to identify the party responsible for
providing evaluation evidence to the evaluator.
96
The evaluator shall report the identity of the evaluator.
97
The identity of the evaluator is required to identify the party performing the
evaluation and responsible for the evaluation verdicts.
8.5.5.2.2
Evaluation
98
The evaluator shall report the evaluation methods, techniques, tools and
standards used.
99
The evaluator references the evaluation criteria, methodology and
interpretations used to evaluate the PP.
100
The evaluator shall report any constraints on the evaluation, constraints on
the handling of evaluation results and assumptions made during the
evaluation that have an impact on the evaluation results.
101
The evaluator may include information in relation to legal or statutory
aspects, organisation, confidentiality, etc.
8.5.5.2.3
Results of the evaluation
102
The evaluator shall report a verdict and a supporting rationale for each
assurance component that constitutes an APE activity, as a result of
performing the corresponding CEM action and its constituent work units.
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103
The rationale justifies the verdict using the CC, the CEM, any interpretations
and the evaluation evidence examined and shows how the evaluation
evidence does or does not meet each aspect of the criteria. It contains a
description of the work performed, the method used, and any derivation of
results. The rationale may provide detail to the level of a CEM work unit.
8.5.5.2.4
Conclusions and recommendations
104
The evaluator shall report the conclusions of the evaluation, in particular the
overall verdict as defined in CC Part 1 Chapter 9, Evaluation results, and
determined by application of the verdict assignment described in 8.2.5.
105
The evaluator provides recommendations that may be useful for the overseer.
These recommendations may include shortcomings of the PP discovered
during the evaluation or mention of features which are particularly useful.
8.5.5.2.5
List of evaluation evidence
106
The evaluator shall report for each item of evaluation evidence the following
information:
−
the issuing body (e.g. the developer, the sponsor);
−
the title;
−
the unique reference (e.g. issue date and version number).
8.5.5.2.6
List of acronyms/Glossary of terms
107
The evaluator shall report any acronyms or abbreviations used in the ETR.
108
Glossary definitions already defined by the CC or CEM need not be repeated
in the ETR.
8.5.5.2.7
Observation reports
109
The evaluator shall report a complete list that uniquely identifies the ORs
raised during the evaluation and their status.
110
For each OR, the list should contain its identifier as well as its title or a brief
summary of its content.
8.5.5.3
ETR for a TOE Evaluation
111
This Section describes the minimum content of the ETR for a TOE
evaluation. The contents of the ETR are portrayed in Figure 5; this figure
may be used as a guide when constructing the structural outline of the ETR
document.
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Figure 5 - ETR information content for a TOE evaluation
8.5.5.3.1
Introduction
112
The evaluator shall report evaluation scheme identifiers.
113
Evaluation scheme identifiers (e.g. logos) are the information required to
unambiguously identify the scheme responsible for the evaluation oversight.
114
The evaluator shall report ETR configuration control identifiers.
115
The ETR configuration control identifiers contain information that identifies
the ETR (e.g. name, date and version number).
116
The evaluator shall report ST and TOE configuration control identifiers.
117
ST and TOE configuration control identifiers identify what is being
evaluated in order for the overseer to verify that the verdicts have been
assigned correctly by the evaluator.
118
If the ST claims that the TOE conforms to the requirements of one or more
PPs, the ETR shall report the reference of the corresponding PPs.
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119
The PPs reference contains information that uniquely identifies the PPs (e.g.
title, date, and version number).
120
The evaluator shall report the identity of the developer.
121
The identity of the TOE developer is required to identify the party
responsible for producing the TOE.
122
The evaluator shall report the identity of the sponsor.
123
The identity of the sponsor is required to identify the party responsible for
providing evaluation evidence to the evaluator.
124
The evaluator shall report the identity of the evaluator.
125
The identity of the evaluator is required to identify the party performing the
evaluation and responsible for the evaluation verdicts.
8.5.5.3.2
Architectural description of the TOE
126
The evaluator shall report a high level description of the TOE and its major
components based on the evaluation evidence described in the CC assurance
family entitled TOE design (ADV_TDS), where applicable.
127
The intent of this Section is to characterise the degree of architectural
separation of the major components. If there is no TOE design (ADV_TDS)
requirement in the ST, this is not applicable and is considered to be satisfied.
8.5.5.3.3
Evaluation
128
The evaluator shall report the evaluation methods, techniques, tools and
standards used.
129
The evaluator may reference the evaluation criteria, methodology and
interpretations used to evaluate the TOE or the devices used to perform the
tests.
130
The evaluator shall report any constraints on the evaluation, constraints on
the distribution of evaluation results and assumptions made during the
evaluation that have an impact on the evaluation results.
131
The evaluator may include information in relation to legal or statutory
aspects, organisation, confidentiality, etc.
8.5.5.3.4
Results of the evaluation
132
For each activity on which the TOE is evaluated, the evaluator shall report:
−
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−
a verdict and a supporting rationale for each assurance component
that constitutes this activity, as a result of performing the
corresponding CEM action and its constituent work units.
133
The rationale justifies the verdict using the CC, the CEM, any interpretations
and the evaluation evidence examined and shows how the evaluation
evidence does or does not meet each aspect of the criteria. It contains a
description of the work performed, the method used, and any derivation of
results. The rationale may provide detail to the level of a CEM work unit.
134
The evaluator shall report all information specifically required by a work
unit.
135
For the AVA and ATE activities, work units that identify information to be
reported in the ETR have been defined.
8.5.5.3.5
Conclusions and recommendations
136
The evaluator shall report the conclusions of the evaluation, which will
relate to whether the TOE has satisfied its associated ST, in particular the
overall verdict as defined in CC Part 1 Chapter 9, Evaluation results, and
determined by application of the verdict assignment described in 8.2.5.
137
The evaluator provides recommendations that may be useful for the overseer.
These recommendations may include shortcomings of the IT product
discovered during the evaluation or mention of features which are
particularly useful.
8.5.5.3.6
List of evaluation evidence
138
The evaluator shall report for each item of evaluation evidence the following
information:
−
the issuing body (e.g. the developer, the sponsor);
−
the title;
−
the unique reference (e.g. issue date and version number).
8.5.5.3.7
List of acronyms/Glossary of terms
139
The evaluator shall report any acronyms or abbreviations used in the ETR.
140
Glossary definitions already defined by the CC or CEM need not be repeated
in the ETR.
8.5.5.3.8
Observation reports
141
The evaluator shall report a complete list that uniquely identifies the ORs
raised during the evaluation and their status.
142
For each OR, the list should contain its identifier as well as its title or a brief
summary of its content.
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9
Class APE: Protection Profile evaluation
9.1
Introduction
143
This Chapter describes the evaluation of a PP. The requirements and
methodology for PP evaluation are identical for each PP evaluation,
regardless of the EAL (or other set of assurance requirements) that is claimed
in the PP. The evaluation methodology in this Chapter is based on the
requirements on the PP as specified in CC Part 3 class APE.
144
This Chapter should be used in conjunction with Annexes A, B and C in CC
Part 1, as these Annexes clarify the concepts here and provide many
examples.
9.2
Application notes
9.2.1
Re-using the evaluation results of certified PPs
145
While evaluating a PP that is based on one or more certified PPs, it may be
possible to re-use the fact that these PPs were certified. The potential for reuse of the result of a certified PP is greater if the PP under evaluation does
not add threats, OSPs, assumptions, security objectives and/or security
requirements to those of the PP that conformance is being claimed to. If the
PP under evaluation contains much more than the certified PP, re-use may
not be useful at all.
146
The evaluator is allowed to re-use the PP evaluation results by doing certain
analyses only partially or not at all if these analyses or parts thereof were
already done as part of the PP evaluation. While doing this, the evaluator
should assume that the analyses in the PP were performed correctly.
147
An example would be where the PP that conformance is being claimed to
contains a set of security requirements, and these were determined to be
internally consistent during its evaluation. If the PP under evaluation uses the
exact same requirements, the consistency analysis does not have to be
repeated during the ST evaluation. If the PP under evaluation adds one or
more requirements, or performs operations on these requirements, the
analysis will have to be repeated. However, it may be possible to save work
in this consistency analysis by using the fact that the original requirements
are internally consistent. If the original requirements are internally
consistent, the evaluator only has to determine that:
148
a)
the set of all new and/or changed requirements is internally
consistent, and
b)
the set of all new and/or changed requirements is consistent with the
original requirements.
The evaluator notes in the ETR each case where analyses are not done or
only partially done for this reason.
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9.3
PP introduction (APE_INT)
9.3.1
Evaluation of sub-activity (APE_INT.1)
9.3.1.1
Objectives
149
The objective of this sub-activity is to determine whether the PP is correctly
identified, and whether the PP reference and TOE overview are consistent
with each other.
9.3.1.2
Input
150
The evaluation evidence for this sub-activity is:
a)
the PP.
9.3.1.3
Action APE_INT.1.1E
APE_INT.1.1C
The PP introduction shall contain a PP reference and a TOE overview.
APE_INT.1-1
The evaluator shall check that the PP introduction contains a PP reference
and a TOE overview.
APE_INT.1.2C
The PP reference shall uniquely identify the PP.
APE_INT.1-2
The evaluator shall examine the PP reference to determine that it uniquely
identifies the PP.
151
The evaluator determines that the PP reference identifies the PP itself, so that
it may be easily distinguished from other PPs, and that it also uniquely
identifies each version of the PP, e.g. by including a version number and/or a
date of publication.
152
The PP should have some referencing system that is capable of supporting
unique references (e.g. use of numbers, letters or dates).
APE_INT.1.3C
The TOE overview shall summarise the usage and major security features
of the TOE.
APE_INT.1-3
The evaluator shall examine the TOE overview to determine that it describes
the usage and major security features of the TOE.
153
The TOE overview should briefly (i.e. several paragraphs) describe the usage
and major security features expected of the TOE. The TOE overview should
enable consumers and potential TOE developers to quickly determine
whether the PP is of interest to them.
154
The evaluator determines that the overview is clear enough for TOE
developers and consumers, and sufficient to give them a general
understanding of the intended usage and major security features of the TOE.
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APE_INT.1.4C
The TOE overview shall identify the TOE type.
APE_INT.1-4
The evaluator shall check that the TOE overview identifies the TOE type.
APE_INT.1.5C
The
TOE
overview
shall
identify
hardware/software/firmware available to the TOE.
APE_INT.1-5
The evaluator shall examine the TOE overview to determine that it identifies
any non-TOE hardware/software/firmware available to the TOE.
155
While some TOEs may run stand-alone, other TOEs (notably software
TOEs) need additional hardware, software or firmware to operate. In this
section of the PP, the PP author lists all hardware, software, and/or firmware
that will be available for the TOE to run on.
156
This identification should be detailed enough for potential consumers and
TOE developers to determine whether their TOE may operate with the listed
hardware, software and firmware.
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non-TOE
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9.4
Conformance claims (APE_CCL)
9.4.1
Evaluation of sub-activity (APE_CCL.1)
9.4.1.1
Objectives
157
The objective of this sub-activity is to determine the validity of various
conformance claims. These describe how the PP conforms to the CC, other
PPs and packages.
9.4.1.2
Input
158
The evaluation evidence for this sub-activity is:
a)
the PP;
b)
the PP(s) that the PP claims conformance to;
c)
the package(s) that the PP claims conformance to.
9.4.1.3
Action APE_CCL.1.1E
APE_CCL.1.1C
The conformance claim shall contain a CC conformance claim that
identifies the version of the CC to which the PP claims conformance.
APE_CCL.1-1
The evaluator shall check that the conformance claim contains a CC
conformance claim that identifies the version of the CC to which the PP
claims conformance.
159
The evaluator determines that the CC conformance claim identifies the
version of the CC that was used to develop this PP. This should include the
version number of the CC and, unless the International English version of the
CC was used, the language of the version of the CC that was used.
APE_CCL.1.2C
The CC conformance claim shall describe the conformance of the PP to
CC Part 2 as either CC Part 2 conformant or CC Part 2 extended.
APE_CCL.1-2
The evaluator shall check that the CC conformance claim states a claim of
either CC Part 2 conformant or CC Part 2 extended for the PP.
APE_CCL.1.3C
The CC conformance claim shall describe the conformance of the PP to
CC Part 3 as either CC Part 3 conformant or CC Part 3 extended.
APE_CCL.1-3
The evaluator shall check that the CC conformance claim states a claim of
either CC Part 3 conformant or CC Part 3 extended for the PP.
APE_CCL.1.4C
The CC conformance claim shall be consistent with the extended
components definition.
APE_CCL.1-4
The evaluator shall examine the CC conformance claim for CC Part 2 to
determine that it is consistent with the extended components definition.
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160
If the CC conformance claim contains CC Part 2 conformant, the evaluator
determines that the extended components definition does not define
functional components.
161
If the CC conformance claim contains CC Part 2 extended, the evaluator
determines that the extended components definition defines at least one
extended functional component.
APE_CCL.1-5
The evaluator shall examine the CC conformance claim for CC Part 3 to
determine that it is consistent with the extended components definition.
162
If the CC conformance claim contains CC Part 3 conformant, the evaluator
determines that the extended components definition does not define
assurance components.
163
If the CC conformance claim contains CC Part 3 extended, the evaluator
determines that the extended components definition defines at least one
extended assurance component.
APE_CCL.1.5C
The conformance claim shall identify all PPs and security requirement
packages to which the PP claims conformance.
APE_CCL.1-6
The evaluator shall check that the conformance claim contains a PP claim
that identifies all PPs for which the PP claims conformance.
164
If the PP does not claim conformance to another PP, this work unit is not
applicable and therefore considered to be satisfied.
165
The evaluator determines that any referenced PPs are unambiguously
identified (e.g. by title and version number, or by the identification included
in the introduction of that PP).
166
The evaluator is reminded that claims of partial conformance to a PP are not
permitted.
APE_CCL.1-7
The evaluator shall check that the conformance claim contains a package
claim that identifies all packages to which the PP claims conformance.
167
If the PP does not claim conformance to a package, this work unit is not
applicable and therefore considered to be satisfied.
168
The evaluator determines that any referenced packages are unambiguously
identified (e.g. by title and version number, or by the identification included
in the introduction of that package).
169
The evaluator is reminded that claims of partial conformance to a package
are not permitted.
APE_CCL.1.6C
The conformance claim shall describe any conformance of the PP to a
package as either package-conformant or package-augmented.
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APE_CCL.1-8
The evaluator shall check that, for each identified package, the conformance
claim states a claim of either package-name conformant or package-name
augmented.
170
If the PP does not claim conformance to a package, this work unit is not
applicable and therefore considered to be satisfied.
171
If the package conformance claim contains package-name conformant, the
evaluator determines that:
172
a)
If the package is an assurance package, then the PP contains all SARs
included in the package, but no additional SARs.
b)
If the package is a functional package, then the PP contains all SFRs
included in the package, but no additional SFRs.
If the package conformance claim contains package-name augmented, the
evaluator determines that:
a)
If the package is an assurance package, then the PP contains all SARs
included in the package, and at least one additional SAR or at least
one SAR that is hierarchical to a SAR in the package.
b)
If the package is a functional package, then the PP contains all SFRs
included in the package, and at least one additional SFR or at least
one SFR that is hierarchical to a SFR in the package.
APE_CCL.1.7C
The conformance claim rationale shall demonstrate that the TOE type is
consistent with the TOE type in the PPs for which conformance is being
claimed.
APE_CCL.1-9
The evaluator shall examine the conformance claim rationale to determine
that the TOE type of the TOE is consistent with all TOE types of the PPs.
173
If the PP does not claim conformance to another PP, this work unit is not
applicable and therefore considered to be satisfied.
174
The relation between the types may be simple: a firewall PP claiming
conformance to another firewall PP, or more complex: a smart card PP
claiming conformance to a number of other PPs at the same time: a PP for
the integrated circuit, a PP for the smart card OS, and two PPs for two
applications on the smart card.
APE_CCL.1.8C
The conformance claim rationale shall demonstrate that the statement of
the security problem definition is consistent with the statement of the
security problem definition in the PPs for which conformance is being
claimed.
APE_CCL.1-10
The evaluator shall examine the conformance claim rationale to determine
that it demonstrates that the statement of security problem definition is
consistent, as defined by the conformance statement of the PP, with the
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statements of security problem definition stated in the PPs to which
conformance is being claimed.
175
If the PP under evaluation does not claim conformance with another PP, this
work unit is not applicable and therefore considered to be satisfied.
176
If the PP to which conformance is being claimed does not have a statement
of security problem definition, this work unit is not applicable and therefore
considered to be satisfied.
177
If strict conformance is required by the PP to which conformance is being
claimed, no conformance claim rationale is required. Instead, the evaluator
determines whether
a)
the threats in the PP under evaluation are a superset of or identical to
the threats in the PP to which conformance is being claimed;
b)
the OSPs in the PP under evaluation are a superset of or identical to
the OSPs in the PP to which conformance is being claimed;
c)
the assumptions in the PP under evaluation are identical to the OSPs
in the PP to which conformance is being claimed;
178
If demonstrable conformance is required by the PP to which conformance is
being claimed, the evaluator examines the conformance claim rationale to
determine that it demonstrates that the statement of security problem
definition of the PP under evaluation is equivalent or more restrictive than
the statement of security problem definition in the PP to which conformance
is being claimed.
179
For guidance on “equivalent or more restrictive” see CC Part 1 Annex D, PP
conformance.
APE_CCL.1.9C
The conformance claim rationale shall demonstrate that the statement of
security objectives is consistent with the statement of security objectives in
the PPs for which conformance is being claimed.
APE_CCL.1-11
The evaluator shall examine the conformance claim rationale to determine
that the statement of security objectives is consistent, as defined by the
conformance statement of the PPs, with the statement of security objectives
in the PPs.
180
If the PP does not claim conformance to another PP, this work unit is not
applicable and therefore considered to be satisfied.
181
If strict conformance is required by the PP to which conformance is being
claimed, no conformance claim rationale is required. Instead, the evaluator
determines whether:
−
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The PP under evaluation contains all security objectives for the TOE
of the PP to which conformance is being claimed. Note that it is
allowed for the PP under evaluation to have additional security
objectives for the TOE;
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−
The PP under evaluation contains exactly all security objectives for
the operational environment (with one exception in the next bullet).
Note that it is not allowed for the PP under evaluation to have
additional security objectives for the operational environment;
−
The PP under evaluation may specify that certain objectives for the
operational environment in the PP that conformance is being claimed
to are security objectives for the TOE in the PP under evaluation.
This is a valid exception to the previous bullet.
182
If demonstrable conformance is required by the PP to which conformance is
being claimed, the evaluator examines the conformance claim rationale to
determine that it demonstrates that the statement of security objectives of the
PP under evaluation is equivalent or more restrictive than the statement of
security objectives in the PP to which conformance is being claimed.
183
For guidance on “equivalent or more restrictive” see CC Part 1 Annex D, PP
conformance.
APE_CCL.1.10C
The conformance claim rationale shall demonstrate that the statement of
security requirements is consistent with the statement of security
requirements in the PPs for which conformance is being claimed.
APE_CCL.1-12
The evaluator shall examine the PP to determine that it is consistent, as
defined by the conformance statement of the PP, with all security
requirements in the PPs for which conformance is being claimed.
184
If the PP does not claim conformance to another PP, this work unit is not
applicable and therefore considered to be satisfied.
185
If strict conformance is required by the PP to which conformance is being
claimed, no conformance claim rationale is required. Instead, the evaluator
determines whether the statement of security requirements in the PP under
evaluation is a superset of or identical to the statement of security
requirements in the PP to which conformance is being claimed (for strict
conformance).
186
If demonstrable conformance is required by the PP to which conformance is
being claimed, the evaluator examines the conformance claim rationale to
determine that it demonstrates that the statement of security requirements of
the PP under evaluation is equivalent or more restrictive than the statement
of security requirements in the PP to which conformance is being claimed.
187
For guidance on “equivalent or more restrictive” see CC Part 1 Annex D, PP
conformance.
APE_CCL.1.11C
The conformance statement shall describe the conformance required of
any PPs/STs to the PP as strict-PP or demonstrable-PP conformance.
APE_CCL.1-13
The evaluator shall check that the PP conformance statement states a claim
of strict-PP or demonstrable-PP conformance.
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9.5
Security problem definition (APE_SPD)
9.5.1
Evaluation of sub-activity (APE_SPD.1)
9.5.1.1
Objectives
188
The objective of this sub-activity is to determine that the security problem
intended to be addressed by the TOE and its operational environment is
clearly defined.
9.5.1.2
Input
189
The evaluation evidence for this sub-activity is:
a)
the PP.
9.5.1.3
Action APE_SPD.1.1E
APE_SPD.1.1C
The security problem definition shall describe the threats.
APE_SPD.1-1
The evaluator shall check that the security problem definition describes the
threats.
190
If all security objectives are derived from assumptions and/or OSPs only, the
statement of threats need not be present in the PP. In this case, this work unit
is not applicable and therefore considered to be satisfied.
191
The evaluator determines that the security problem definition describes the
threats that must be countered by the TOE and/or its operational
environment.
APE_SPD.1.2C
All threats shall be described in terms of a threat agent, an asset, and an
adverse action.
APE_SPD.1-2
The evaluator shall examine the security problem definition to determine
that all threats are described in terms of a threat agent, an asset, and an
adverse action.
192
If all security objectives are derived from assumptions and OSPs only, the
statement of threats need not be present in the PP. In this case, this work unit
is not applicable and therefore considered to be satisfied.
193
Threat agents may be further described by aspects such as expertise,
resource, opportunity, and motivation.
APE_SPD.1.3C
The security problem definition shall describe the OSPs.
APE_SPD.1-3
The evaluator shall check that the security problem definition describes the
OSPs.
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194
If all security objectives are derived from assumptions and/or threats only,
OSPs need not be present in the PP. In this case, this work unit is not
applicable and therefore considered to be satisfied.
195
The evaluator determines that OSP statements are made in terms of rules or
guidelines that must be followed by the TOE and/or its operational
environment.
196
The evaluator determines that each OSP is explained and/or interpreted in
sufficient detail to make it clearly understandable; a clear presentation of
policy statements is necessary to permit tracing security objectives to them.
APE_SPD.1.4C
The security problem definition shall describe the assumptions about the
operational environment of the TOE.
APE_SPD.1-4
The evaluator shall examine the security problem definition to determine
that it describes the assumptions about the operational environment of the
TOE.
197
If there are no assumptions, this work unit is not applicable and is therefore
considered to be satisfied.
198
The evaluator determines that each assumption about the operational
environment of the TOE is explained in sufficient detail to enable consumers
to determine that their operational environment matches the assumption. If
the assumptions are not clearly understood, the end result may be that the
TOE is used in an operational environment in which it will not function in a
secure manner.
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9.6
Security objectives (APE_OBJ)
9.6.1
Evaluation of sub-activity (APE_OBJ.1)
9.6.1.1
Objectives
199
The objective of this sub-activity is to determine whether the security
objectives for the operational environment are clearly defined.
9.6.1.2
Input
200
The evaluation evidence for this sub-activity is:
a)
the PP.
9.6.1.3
Action APE_OBJ.1.1E
APE_OBJ.1.1C
The statement of security objectives shall describe the security objectives
for the operational environment.
APE_OBJ.1-1
The evaluator shall check that the statement of security objectives defines
the security objectives for the operational environment.
201
The evaluator checks that the security objectives for the operational
environment are identified.
9.6.2
Evaluation of sub-activity (APE_OBJ.2)
9.6.2.1
Objectives
202
The objective of this sub-activity is to determine whether the security
objectives adequately and completely address the security problem definition
and that the division of this problem between the TOE and its operational
environment is clearly defined.
9.6.2.2
Input
203
The evaluation evidence for this sub-activity is:
a)
the PP.
9.6.2.3
Action APE_OBJ.2.1E
APE_OBJ.2.1C
The statement of security objectives shall describe the security objectives
for the TOE and the security objectives for the operational environment.
APE_OBJ.2-1
The evaluator shall check that the statement of security objectives defines
the security objectives for the TOE and the security objectives for the
operational environment.
204
The evaluator checks that both categories of security objectives are clearly
identified and separated from the other category.
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APE_OBJ.2.2C
The security objectives rationale shall trace each security objective for the
TOE back to threats countered by that security objective and OSPs
enforced by that security objective.
APE_OBJ.2-2
The evaluator shall check that the security objectives rationale traces all
security objectives for the TOE back to threats countered by the objectives
and/or OSPs enforced by the objectives.
205
Each security objective for the TOE may trace back to threats or OSPs, or a
combination of threats and OSPs, but it must trace back to at least one threat
or OSP.
206
Failure to trace implies that either the security objectives rationale is
incomplete, the security problem definition is incomplete, or the security
objective for the TOE has no useful purpose.
APE_OBJ.2.3C
The security objectives rationale shall trace each security objective for the
operational environment back to threats countered by that security
objective, OSPs enforced by that security objective, and assumptions
upheld by that security objective.
APE_OBJ.2-3
The evaluator shall check that the security objectives rationale traces the
security objectives for the operational environment back to threats countered
by that security objective, to OSPs enforced by that security objective, and to
assumptions upheld by that security objective.
207
Each security objective for the operational environment may trace back to
threats, OSPs, assumptions, or a combination of threats, OSPs and/or
assumptions, but it must trace back to at least one threat, OSP or assumption.
208
Failure to trace implies that either the security objectives rationale is
incomplete, the security problem definition is incomplete, or the security
objective for the operational environment has no useful purpose.
APE_OBJ.2.4C
The security objectives rationale shall demonstrate that the security
objectives counter all threats.
APE_OBJ.2-4
The evaluator shall examine the security objectives rationale to determine
that it justifies for each threat that the security objectives are suitable to
counter that threat.
209
If no security objectives trace back to the threat, this work unit fails.
210
The evaluator determines that the justification for a threat shows whether the
threat is removed, diminished or mitigated.
211
The evaluator determines that the justification for a threat demonstrates that
the security objectives are sufficient: if all security objectives that trace back
to the threat are achieved, the threat is removed, sufficiently diminished, or
the effects of the threat are sufficiently mitigated.
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212
Note that the tracings from security objectives to threats provided in the
security objectives rationale may be part of a justification, but do not
constitute a justification by themselves. Even in the case that a security
objective is merely a statement reflecting the intent to prevent a particular
threat from being realised, a justification is required, but this justification
may be as minimal as “Security Objective X directly counters Threat Y”.
213
The evaluator also determines that each security objective that traces back to
a threat is necessary: when the security objective is achieved it actually
contributes to the removal, diminishing or mitigation of that threat.
APE_OBJ.2.5C
The security objectives rationale shall demonstrate that the security
objectives enforce all OSPs.
APE_OBJ.2-5
The evaluator shall examine the security objectives rationale to determine
that for each OSP it justifies that the security objectives are suitable to
enforce that OSP.
214
If no security objectives trace back to the OSP, this work unit fails.
215
The evaluator determines that the justification for an OSP demonstrates that
the security objectives are sufficient: if all security objectives that trace back
to that OSP are achieved, the OSP is enforced.
216
The evaluator also determines that each security objective that traces back to
an OSP is necessary: when the security objective is achieved it actually
contributes to the enforcement of the OSP.
217
Note that the tracings from security objectives to OSPs provided in the
security objectives rationale may be part of a justification, but do not
constitute a justification by themselves. In the case that a security objective is
merely a statement reflecting the intent to enforce a particular OSP, a
justification is required, but this justification may be as minimal as “Security
Objective X directly enforces OSP Y”.
APE_OBJ.2.6C
The security objectives rationale shall demonstrate that the security
objectives for the operational environment uphold all assumptions.
APE_OBJ.2-6
The evaluator shall examine the security objectives rationale to determine
that for each assumption for the operational environment it contains an
appropriate justification that the security objectives for the operational
environment are suitable to uphold that assumption.
218
If no security objectives for the operational environment trace back to the
assumption, this work unit fails.
219
The evaluator determines that the justification for an assumption about the
operational environment of the TOE demonstrates that the security objectives
are sufficient: if all security objectives for the operational environment that
trace back to that assumption are achieved, the operational environment
upholds the assumption.
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220
The evaluator also determines that each security objective for the operational
environment that traces back to an assumption about the operational
environment of the TOE is necessary: when the security objective is
achieved it actually contributes to the operational environment upholding the
assumption.
221
Note that the tracings from security objectives for the operational
environment to assumptions provided in the security objectives rationale may
be a part of a justification, but do not constitute a justification by themselves.
Even in the case that a security objective of the operational environment is
merely a restatement of an assumption, a justification is required, but this
justification may be as minimal as “Security Objective X directly upholds
Assumption Y”.
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9.7
Extended components definition (APE_ECD)
9.7.1
Evaluation of sub-activity (APE_ECD.1)
9.7.1.1
Objectives
222
The objective of this sub-activity is to determine whether extended
components have been clearly and unambiguously defined, and whether they
are necessary, i.e. they may not be clearly expressed using existing CC Part 2
or CC Part 3 components.
9.7.1.2
Input
223
The evaluation evidence for this sub-activity is:
a)
the PP.
9.7.1.3
Action APE_ECD.1.1E
APE_ECD.1.1C
The statement of security requirements shall identify all extended security
requirements.
APE_ECD.1-1
The evaluator shall check that all security requirements in the statement of
security requirements that are not identified as extended requirements are
present in CC Part 2 or in CC Part 3.
APE_ECD.1.2C
The extended components definition shall define an extended component
for each extended security requirement.
APE_ECD.1-2
The evaluator shall check that the extended components definition defines
an extended component for each extended security requirement.
224
If the PP does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
225
A single extended component may be used to define multiple iterations of an
extended security requirement, it is not necessary to repeat this definition for
each iteration.
APE_ECD.1.3C
The extended components definition shall describe how each extended
component is related to the existing CC components, families, and classes.
APE_ECD.1-3
The evaluator shall examine the extended components definition to
determine that it describes how each extended component fits into the
existing CC components, families, and classes.
226
If the PP does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
227
The evaluator determines that each extended component is either:
a)
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a member of a new family defined in the PP.
228
If the extended component is a member of an existing CC Part 2 or CC Part 3
family, the evaluator determines that the extended components definition
adequately describes why the extended component should be a member of
that family and how it relates to other components of that family.
229
If the extended component is a member of a new family defined in the PP,
the evaluator confirms that the extended component is not appropriate for an
existing family.
230
If the PP defines new families, the evaluator determines that each new family
is either:
a)
a member of an existing CC Part 2 or CC Part 3 class, or
b)
a member of a new class defined in the PP.
231
If the family is a member of an existing CC Part 2 or CC Part 3 class, the
evaluator determines that the extended components definition adequately
describes why the family should be a member of that class and how it relates
to other families in that class.
232
If the family is a member of a new class defined in the PP, the evaluator
confirms that the family is not appropriate for an existing class.
APE_ECD.1-4
The evaluator shall examine the extended components definition to
determine that each definition of an extended component identifies all
applicable dependencies of that component.
233
If the PP does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
234
The evaluator confirms that no applicable dependencies have been
overlooked by the PP author.
APE_ECD.1.4C
The extended components definition shall use the existing CC components,
families, classes, and methodology as a model for presentation.
APE_ECD.1-5
The evaluator shall examine the extended components definition to
determine that each extended functional component uses the existing CC Part
2 components as a model for presentation.
235
If the PP does not contain extended SFRs, this work unit is not applicable
and therefore considered to be satisfied.
236
The evaluator determines that the extended functional component is
consistent with CC Part 2 Section 7.1.3, Component structure.
237
If the extended functional component uses operations, the evaluator
determines that the extended functional component is consistent with CC
Part 1 Annex C.4, Operations.
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238
If the extended functional component is hierarchical to an existing functional
component, the evaluator determines that the extended functional component
is consistent with CC Part 2 Section 7.2.1, Component changes highlighting.
APE_ECD.1-6
The evaluator shall examine the extended components definition to
determine that each definition of a new functional family uses the existing
CC functional families as a model for presentation.
239
If the PP does not define new functional families, this work unit is not
applicable and therefore considered to be satisfied.
240
The evaluator determines that all new functional families are defined
consistent with CC Part 2 Section 7.1.2, Family structure.
APE_ECD.1-7
The evaluator shall examine the extended components definition to
determine that each definition of a new functional class uses the existing CC
functional classes as a model for presentation.
241
If the PP does not define new functional classes, this work unit is not
applicable and therefore considered to be satisfied.
242
The evaluator determines that all new functional classes are defined
consistent with CC Part 2 Section 7.1.1, Class structure
APE_ECD.1-8
The evaluator shall examine the extended components definition to
determine that each definition of an extended assurance component uses the
existing CC Part 3 components as a model for presentation.
243
If the PP does not contain extended SARs, this work unit is not applicable
and therefore considered to be satisfied.
244
The evaluator determines that the extended assurance component definition
is consistent with CC Part 3 Section 7.1.3, Assurance component structure.
245
If the extended assurance component uses operations, the evaluator
determines that the extended assurance component is consistent with CC Part
1 Annex C.4, Operations.
246
If the extended assurance component is hierarchical to an existing assurance
component, the evaluator determines that the extended assurance component
is consistent with CC Part 3 Section 7.1.3, Assurance component structure.
APE_ECD.1-9
The evaluator shall examine the extended components definition to
determine that, for each defined extended assurance component, applicable
methodology has been provided.
247
If the PP does not contain extended SARs, this work unit is not applicable
and therefore considered to be satisfied.
248
The evaluator determines that, for each evaluator action element of each
extended SAR, one or more work units are provided and that successfully
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performing all work units for a given evaluator action element will
demonstrate that the element has been achieved.
APE_ECD.1-10
The evaluator shall examine the extended components definition to
determine that each definition of a new assurance family uses the existing
CC assurance families as a model for presentation.
249
If the PP does not define new assurance families, this work unit is not
applicable and therefore considered to be satisfied.
250
The evaluator determines that all new assurance families are defined
consistent with CC Part 3 Section 7.1.2, Assurance family structure.
APE_ECD.1-11
The evaluator shall examine the extended components definition to
determine that each definition of a new assurance class uses the existing CC
assurance classes as a model for presentation.
251
If the PP does not define new assurance classes, this work unit is not
applicable and therefore considered to be satisfied.
252
The evaluator determines that all new assurance classes are defined
consistent with CC Part 3 Section 7.1.1, Assurance class structure.
APE_ECD.1.5C
The extended components shall consist of measurable and objective
elements such that conformance or nonconformance to these elements can
be demonstrated.
APE_ECD.1-12
The evaluator shall examine the extended components definition to
determine that each element in each extended component is measurable and
states objective evaluation requirements, such that conformance or
nonconformance can be demonstrated.
253
If the PP does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
254
The evaluator determines that elements of extended functional components
are stated in such a way that they are testable, and traceable through the
appropriate TSF representations.
255
The evaluator also determines that elements of extended assurance
components avoid the need for subjective evaluator judgement.
256
The evaluator is reminded that whilst being measurable and objective is
appropriate for all evaluation criteria, it is acknowledged that no formal
method exists to prove such properties. Therefore the existing CC functional
and assurance components are to be used as a model for determining what
constitutes conformance to this requirement.
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9.7.1.4
Action APE_ECD.1.2E
APE_ECD.1-13
The evaluator shall examine the extended components definition to
determine that each extended component may not be clearly expressed using
existing components.
257
If the PP does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
258
The evaluator should take components from CC Part 2 and CC Part 3, other
extended components that have been defined in the PP, combinations of
these components, and possible operations on these components into account
when making this determination.
259
The evaluator is reminded that the role of this work unit is to preclude
unnecessary duplication of components, that is, components that may be
clearly expressed by using other components. The evaluator should not
undertake an exhaustive search of all possible combinations of components
including operations in an attempt to find a way to express the extended
component by using existing components.
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9.8
Security requirements (APE_REQ)
9.8.1
Evaluation of sub-activity (APE_REQ.1)
9.8.1.1
Objectives
260
The objective of this sub-activity is to determine whether the SFRs and
SARs are clear, unambiguous and well-defined and whether they are
internally consistent.
9.8.1.2
Input
261
The evaluation evidence for this sub-activity is:
a)
the PP.
9.8.1.3
Action APE_REQ.1.1E
APE_REQ.1.1C
The statement of security requirements shall describe the SFRs and the
SARs.
APE_REQ.1-1
The evaluator shall check that the statement of security requirements
describes the SFRs.
262
The evaluator determines that each SFR is identified by one of the following
means:
a)
by reference to an individual component in CC Part 2;
b)
by reference to an extended component in the extended components
definition of the PP;
c)
by reference to a PP that the PP claims to be conformant with;
d)
by reference to a security requirements package that the PP claims to
be conformant with;
e)
by reproduction in the PP.
263
It is not required to use the same means of identification for all SFRs.
APE_REQ.1-2
The evaluator shall check that the statement of security requirements
describes the SARs.
264
The evaluator determines that each SAR is identified by one of the following
means:
a)
by reference to an individual component in CC Part 3;
b)
by reference to an extended component in the extended components
definition of the PP;
c)
by reference to a PP that the PP claims to be conformant with;
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d)
by reference to a security requirements package that the PP claims to
be conformant with;
e)
by reproduction in the PP.
265
It is not required to use the same means of identification for all SARs.
APE_REQ.1.2C
All subjects, objects, operations, security attributes, external entities and
other terms that are used in the SFRs and the SARs shall be defined.
APE_REQ.1-3
The evaluator shall examine the PP to determine that all subjects, objects,
operations, security attributes, external entities and other terms that are used
in the SFRs and the SARs are defined.
266
The evaluator determines that the PP defines all:
−
(types of) subjects and objects that are used in the SFRs;
−
(types of) security attributes of subjects, users, objects, information,
sessions and/or resources, possible values that these attributes may
take and any relations between these values (e.g. top_secret is
“higher” than secret);
−
(types of) operations that are used in the SFRs, including the effects
of these operations;
−
(types of) external entities in the SFRs;
−
other terms that are introduced in the SFRs and/or SARs by
completing operations, if these terms are not immediately clear, or
are used outside their dictionary definition.
267
The goal of this work unit is to ensure that the SFRs and SARs are welldefined and that no misunderstanding may occur due to the introduction of
vague terms. This work unit should not be taken into extremes, by forcing
the PP writer to define every single word. The general audience of a set of
security requirements should be assumed to have a reasonable knowledge of
IT, security and Common Criteria.
268
All of the above may be presented in groups, classes, roles, types or other
groupings or characterisations that allow easy understanding.
269
The evaluator is reminded that these lists and definitions do not have to be
part of the statement of security requirements, but may be placed (in part or
in whole) in different sections. This may be especially applicable if the same
terms are used in the rest of the PP.
APE_REQ.1.3C
The statement of security requirements shall identify all operations on the
security requirements.
APE_REQ.1-4
The evaluator shall check that the statement of security requirements
identifies all operations on the security requirements.
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270
The evaluator determines that all operations are identified in each SFR or
SAR where such an operation is used. This includes both completed
operations and uncompleted operations. Identification may be achieved by
typographical distinctions, or by explicit identification in the surrounding
text, or by any other distinctive means.
APE_REQ.1.4C
All operations shall be performed correctly.
APE_REQ.1-5
The evaluator shall examine the statement of security requirements to
determine that all assignment operations are performed correctly.
271
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.1-6
The evaluator shall examine the statement of security requirements to
determine that all iteration operations are performed correctly.
272
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.1-7
The evaluator shall examine the statement of security requirements to
determine that all selection operations are performed correctly.
273
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.1-8
The evaluator shall examine the statement of security requirements to
determine that all refinement operations are performed correctly.
274
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.1.5C
Each dependency of the security requirements shall either be satisfied, or
the security requirements rationale shall justify the dependency not being
satisfied.
APE_REQ.1-9
The evaluator shall examine the statement of security requirements to
determine that each dependency of the security requirements is either
satisfied, or that the security requirements rationale justifies the dependency
not being satisfied.
275
A dependency is satisfied by the inclusion of the relevant component (or one
that is hierarchical to it) within the statement of security requirements. The
component used to satisfy the dependency should, if necessary, be modified
by operations to ensure that it actually satisfies that dependency.
276
A justification that a dependency is not met should address either:
a)
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b)
that the dependency has been addressed by the operational
environment of the TOE, in which case the justification should
describe how the security objectives for the operational environment
address this dependency.
APE_REQ.1.6C
The statement of security requirements shall be internally consistent.
APE_REQ.1-10
The evaluator shall examine the statement of security requirements to
determine that it is internally consistent.
277
The evaluator determines that the combined set of all SFRs and SARs is
internally consistent.
278
The evaluator determines that on all occasions where different security
requirements apply to the same types of developer evidence, events,
operations, data, tests to be performed etc. or to “all objects”, “all subjects”
etc., that these requirements do not conflict.
279
Some possible conflicts are:
a)
an extended SAR specifying that the design of a certain
cryptographic algorithm is to be kept secret, and another extended
SAR specifying an open source review;
b)
FAU_GEN.1 Audit data generation specifying that subject identity is
to be logged, FDP_ACC.1 Subset access control specifying who has
access to these logs, and FPR_UNO.1 Unobservability specifying
that some actions of subjects should be unobservable to other
subjects. If the subject that should not be able to see an activity may
access logs of this activity, these SFRs conflict;
c)
FDP_RIP.1 Subset residual information protection specifying
deletion of information no longer needed, and FDP_ROL.1 Basic
rollback specifying that a TOE may return to a previous state. If the
information that is needed for the rollback to the previous state has
been deleted, these requirements conflict;
d)
Multiple iterations of FDP_ACC.1 Subset access control especially
where some iterations cover the same subjects, objects, or operations.
If one access control SFR allows a subject to perform an operation on
an object, while another access control SFR does not allow this, these
requirements conflict.
9.8.2
Evaluation of sub-activity (APE_REQ.2)
9.8.2.1
Objectives
280
The objective of this sub-activity is to determine whether the SFRs and
SARs are clear, unambiguous and well-defined, whether they are internally
consistent, and whether the SFRs meet the security objectives of the TOE.
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9.8.2.2
Input
281
The evaluation evidence for this sub-activity is:
a)
the PP.
9.8.2.3
Action APE_REQ.2.1E
APE_REQ.2.1C
The statement of security requirements shall describe the SFRs and the
SARs.
APE_REQ.2-1
The evaluator shall check that the statement of security requirements
describes the SFRs.
282
The evaluator determines that each SFR is identified by one of the following
means:
a)
by reference to an individual component in CC Part 2;
b)
by reference to an extended component in the extended components
definition of the PP;
c)
by reference to an individual component in a PP that the PP claims to
be conformant with;
d)
by reference to an individual component in a security requirements
package that the PP claims to be conformant with;
e)
by reproduction in the PP.
283
It is not required to use the same means of identification for all SFRs.
APE_REQ.2-2
The evaluator shall check that the statement of security requirements
describes the SARs.
284
The evaluator determines that each SAR is identified by one of the following
means:
285
a)
by reference to an individual component in CC Part 3;
b)
by reference to an extended component in the extended components
definition of the PP;
c)
by reference to an individual component in a PP that the PP claims to
be conformant with;
d)
by reference to an individual component in a security requirements
package that the PP claims to be conformant with;
e)
by reproduction in the PP.
It is not required to use the same means of identification for all SARs.
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APE_REQ.2.2C
All subjects, objects, operations, security attributes, external entities and
other terms that are used in the SFRs and the SARs shall be defined.
APE_REQ.2-3
The evaluator shall examine the PP to determine that all subjects, objects,
operations, security attributes, external entities and other terms that are used
in the SFRs and the SARs are defined.
286
The evaluator determines that the PP defines all:
−
(types of) subjects and objects that are used in the SFRs;
−
(types of) security attributes of subjects, users, objects, information,
sessions and/or resources, possible values that these attributes may
take and any relations between these values (e.g. top_secret is
“higher” than secret);
−
(types of) operations that are used in the SFRs, including the effects
of these operations;
−
(types of) external entities in the SFRs;
−
other terms that are introduced in the SFRs and/or SARs by
completing operations, if these terms are not immediately clear, or
are used outside their dictionary definition.
287
The goal of this work unit is to ensure that the SFRs and SARs are welldefined and that no misunderstanding may occur due to the introduction of
vague terms. This work unit should not be taken into extremes, by forcing
the PP writer to define every single word. The general audience of a set of
security requirements should be assumed to have a reasonable knowledge of
IT, security and Common Criteria.
288
All of the above may be presented in groups, classes, roles, types or other
groupings or characterisations that allow easy understanding.
289
The evaluator is reminded that these lists and definitions do not have to be
part of the statement of security requirements, but may be placed (in part or
in whole) in different sections. This may be especially applicable if the same
terms are used in the rest of the PP.
APE_REQ.2.3C
The statement of security requirements shall identify all operations on the
security requirements.
APE_REQ.2-4
The evaluator shall check that the statement of security requirements
identifies all operations on the security requirements.
290
The evaluator determines that all operations are identified in each SFR or
SAR where such an operation is used. This includes both completed
operations and uncompleted operations. Identification may be achieved by
typographical distinctions, or by explicit identification in the surrounding
text, or by any other distinctive means.
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APE_REQ.2.4C
All operations shall be performed correctly.
APE_REQ.2-5
The evaluator shall examine the statement of security requirements to
determine that all assignment operations are performed correctly.
291
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.2-6
The evaluator shall examine the statement of security requirements to
determine that all iteration operations are performed correctly.
292
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.2-7
The evaluator shall examine the statement of security requirements to
determine that all selection operations are performed correctly.
293
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.2-8
The evaluator shall examine the statement of security requirements to
determine that all refinement operations are performed correctly.
294
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
APE_REQ.2.5C
Each dependency of the security requirements shall either be satisfied, or
the security requirements rationale shall justify the dependency not being
satisfied.
APE_REQ.2-9
The evaluator shall examine the statement of security requirements to
determine that each dependency of the security requirements is either
satisfied, or that the security requirements rationale justifies the dependency
not being satisfied.
295
A dependency is satisfied by the inclusion of the relevant component (or one
that is hierarchical to it) within the statement of security requirements. The
component used to satisfy the dependency should, if necessary, be modified
by operations to ensure that it actually satisfies that dependency.
296
A justification that a dependency is not met should address either:
APE_REQ.2.6C
a)
why the dependency is not necessary or useful, in which case no
further information is required; or
b)
that the dependency has been addressed by the operational
environment of the TOE, in which case the justification should
describe how the security objectives for the operational environment
address this dependency.
The security requirements rationale shall trace each SFR back to the
security objectives for the TOE.
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APE_REQ.2-10
The evaluator shall check that the security requirements rationale traces each
SFR back to the security objectives for the TOE.
297
The evaluator determines that each SFR is traced back to at least one security
objective for the TOE.
298
Failure to trace implies that either the security requirements rationale is
incomplete, the security objectives for the TOE are incomplete, or the SFR
has no useful purpose.
APE_REQ.2.7C
The security requirements rationale shall demonstrate that the SFRs meet
all security objectives for the TOE.
APE_REQ.2-11
The evaluator shall examine the security requirements rationale to determine
that for each security objective for the TOE it justifies that the SFRs are
suitable to meet that security objective for the TOE.
299
If no SFRs trace back to the security objective for the TOE, this work unit
fails.
300
The evaluator determines that the justification for a security objective for the
TOE demonstrates that the SFRs are sufficient: if all SFRs that trace back to
the objective are satisfied, the security objective for the TOE is achieved.
301
If the SFRs that trace back to a security objective for the TOE have any
uncompleted assignments, or uncompleted or restricted selections, the
evaluator determines that for every conceivable completion or combination
of completions of these operations, the security objective is still met.
302
The evaluator also determines that each SFR that traces back to a security
objective for the TOE is necessary: when the SFR is satisfied, it actually
contributes to achieving the security objective.
303
Note that the tracings from SFRs to security objectives for the TOE provided
in the security requirements rationale may be a part of the justification, but
do not constitute a justification by themselves.
APE_REQ.2.8C
The security requirements rationale shall explain why the SARs were
chosen.
APE_REQ.2-12
The evaluator shall check that the security requirements rationale explains
why the SARs were chosen.
304
The evaluator is reminded that any explanation is correct, as long as it is
coherent and neither the SARs nor the explanation have obvious
inconsistencies with the remainder of the PP.
305
An example of an obvious inconsistency between the SARs and the
remainder of the PP would be to have threat agents that are very capable, but
an AVA_VAN SAR that does not protect against these threat agents.
APE_REQ.2.9C
The statement of security requirements shall be internally consistent.
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APE_REQ.2-13
The evaluator shall examine the statement of security requirements to
determine that it is internally consistent.
306
The evaluator determines that the combined set of all SFRs and SARs is
internally consistent.
307
The evaluator determines that on all occasions where different security
requirements apply to the same types of developer evidence, events,
operations, data, tests to be performed etc. or to “all objects”, “all subjects”
etc., that these requirements do not conflict.
308
Some possible conflicts are:
a)
an extended SAR specifying that the design of a certain
cryptographic algorithm is to be kept secret, and another extended
SAR specifying an open source review;
b)
FAU_GEN.1 Audit data generation specifying that subject identity is
to be logged, FDP_ACC.1 Subset access control specifying who has
access to these logs, and FPR_UNO.1 Unobservability specifying
that some actions of subjects should be unobservable to other
subjects. If the subject that should not be able to see an activity may
access logs of this activity, these SFRs conflict;
c)
FDP_RIP.1 Subset residual information protection specifying
deletion of information no longer needed, and FDP_ROL.1 Basic
rollback specifying that a TOE may return to a previous state. If the
information that is needed for the rollback to the previous state has
been deleted, these requirements conflict;
d)
Multiple iterations of FDP_ACC.1 Subset access control especially
where some iterations cover the same subjects, objects, or operations.
If one access control SFR allows a subject to perform an operation on
an object, while another access control SFR does not allow this, these
requirements conflict.
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10.1
Introduction
309
This Chapter describes the evaluation of an ST. The ST evaluation should be
started prior to any TOE evaluation sub-activities since the ST provides the
basis and context to perform these sub-activities. The evaluation
methodology in this section is based on the requirements on the ST as
specified in CC Part 3 class ASE.
310
This Chapter should be used in conjunction with Annexes A, B and C in CC
Part 1, as these Annexes clarify the concepts here and provide many
examples.
10.2
Application notes
10.2.1
Re-using the evaluation results of certified PPs
311
While evaluating an ST that is based on one or more certified PPs, it may be
possible to re-use the fact that these PPs were certified. The potential for reuse of the result of a certified PP is greater if the ST does not add threats,
OSPs, assumptions, security objectives and/or security requirements to those
of the PP. If the ST contains much more than the certified PP, re-use may not
be useful at all.
312
The evaluator is allowed to re-use the PP evaluation results by doing certain
analyses only partially or not at all if these analyses or parts thereof were
already done as part of the PP evaluation. While doing this, the evaluator
should assume that the analyses in the PP were performed correctly.
313
An example would be where the PP contains a set of security requirements,
and these were determined to be internally consistent during the PP
evaluation. If the ST uses the exact same requirements, the consistency
analysis does not have to be repeated during the ST evaluation. If the ST
adds one or more requirements, or performs operations on these
requirements, the analysis will have to be repeated. However, it may be
possible to save work in this consistency analysis by using the fact that the
original requirements are internally consistent. If the original requirements
are internally consistent, the evaluator only has to determine that:
314
a)
the set of all new and/or changed requirements is internally
consistent, and
b)
the set of all new and/or changed requirements is consistent with the
original requirements.
The evaluator notes in the ETR each case where analyses are not done or
only partially done for this reason.
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10.3
ST introduction (ASE_INT)
10.3.1
Evaluation of sub-activity (ASE_INT.1)
10.3.1.1
Objectives
315
The objective of this sub-activity is to determine whether the ST and the
TOE are correctly identified, whether the TOE is correctly described in a
narrative way at three levels of abstraction (TOE reference, TOE overview
and TOE description), and whether these three descriptions are consistent
with each other.
10.3.1.2
Input
316
The evaluation evidence for this sub-activity is:
a)
the ST.
10.3.1.3
Action ASE_INT.1.1E
ASE_INT.1.1C
The ST introduction shall contain an ST reference, a TOE reference, a
TOE overview and a TOE description.
ASE_INT.1-1
The evaluator shall check that the ST introduction contains an ST reference,
a TOE reference, a TOE overview and a TOE description.
ASE_INT.1.2C
The ST reference shall uniquely identify the ST.
ASE_INT.1-2
The evaluator shall examine the ST reference to determine that it uniquely
identifies the ST.
317
The evaluator determines that the ST reference identifies the ST itself, so that
it may be easily distinguished from other STs, and that it also uniquely
identifies each version of the ST, e.g. by including a version number and/or a
date of publication.
318
In evaluations where a CM system is provided, the evaluator may validate
the uniqueness of the reference by checking the configuration list. In the
other cases, the ST should have some referencing system that is capable of
supporting unique references (e.g. use of numbers, letters or dates).
ASE_INT.1.3C
The TOE reference shall identify the TOE.
ASE_INT.1-3
The evaluator shall examine the TOE reference to determine that it identifies
the TOE.
319
The evaluator determines that the TOE reference identifies the TOE, so that
it is clear to which TOE the ST refers, and that it also identifies the version
of the TOE, e.g. by including a version/release/build number, or a date of
release.
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ASE_INT.1-4
The evaluator shall examine the TOE reference to determine that it is not
misleading.
320
If the TOE is related to one or more well-known products, it is allowed to
reflect this in the TOE reference. However, this should not be used to
mislead consumers: situations where only a small part of a product is
evaluated, yet the TOE reference does not reflect this, are not allowed.
ASE_INT.1.4C
The TOE overview shall summarise the usage and major security features
of the TOE.
ASE_INT.1-5
The evaluator shall examine the TOE overview to determine that it describes
the usage and major security features of the TOE.
321
The TOE overview should briefly (i.e. several paragraphs) describe the usage
and major security features of the TOE. The TOE overview should enable
potential consumers to quickly determine whether the TOE may be suitable
for their security needs.
322
The TOE overview in an ST for a composed TOE should describe the usage
and major security feature of the composed TOE, rather than those of the
individual component TOEs.
323
The evaluator determines that the overview is clear enough for consumers,
and sufficient to give them a general understanding of the intended usage and
major security features of the TOE.
ASE_INT.1.5C
The TOE overview shall identify the TOE type.
ASE_INT.1-6
The evaluator shall check that the TOE overview identifies the TOE type.
ASE_INT.1-7
The evaluator shall examine the TOE overview to determine that the TOE
type is not misleading.
324
There are situations where the general consumer would expect certain
functionality of the TOE because of its TOE type. If this functionality is
absent in the TOE, the evaluator determines that the TOE overview
adequately discusses this absence.
325
There are also TOEs where the general consumer would expect that the TOE
should be able to operate in a certain operational environment because of its
TOE type. If the TOE is unable to operate in such an operational
environment, the evaluator determines that the TOE overview adequately
discusses this.
ASE_INT.1.6C
The
TOE
overview
shall
identify
hardware/software/firmware required by the TOE.
ASE_INT.1-8
The evaluator shall examine the TOE overview to determine that it identifies
any non-TOE hardware/software/firmware required by the TOE.
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326
While some TOEs are able to run stand-alone, other TOEs (notably software
TOEs) need additional hardware, software or firmware to operate. If the TOE
does not require any hardware, software or firmware, this work unit is not
applicable and therefore considered to be satisfied.
327
The evaluator determines that the TOE overview identifies any additional
hardware, software and firmware needed by the TOE to operate. This
identification does not have to be exhaustive, but detailed enough for
potential consumers of the TOE to determine whether their current hardware,
software and firmware support use of the TOE, and, if this is not the case,
which additional hardware, software and/or firmware is needed.
ASE_INT.1.7C
The TOE description shall describe the physical scope of the TOE.
ASE_INT.1-9
The evaluator shall examine the TOE description to determine that it
describes the physical scope of the TOE.
328
The evaluator determines that the TOE description lists the hardware,
firmware, software and guidance parts that constitute the TOE and describes
them at a level of detail that is sufficient to give the reader a general
understanding of those parts.
329
The evaluator also determines that there is no possible misunderstanding as
to whether any hardware, firmware, software or guidance part is part of the
TOE or not.
ASE_INT.1.8C
The TOE description shall describe the logical scope of the TOE.
ASE_INT.1-10
The evaluator shall examine the TOE description to determine that it
describes the logical scope of the TOE.
330
The evaluator determines that the TOE description discusses the logical
security features offered by the TOE at a level of detail that is sufficient to
give the reader a general understanding of those features.
331
The evaluator also determines that there is no possible misunderstanding as
to whether any logical security feature is offered by the TOE or not.
332
An ST for a composed TOE may refer out to the description of the logical
scope of the component TOEs, provided in the component TOE STs to
provide the majority of this description for the composed TOE. However, the
evaluator determines that the composed TOE ST clearly discusses which
features of the individual components are not within the composed TOE, and
therefore not a feature of the composed TOE.
10.3.1.4
Action ASE_INT.1.2E
ASE_INT.1-11
The evaluator shall examine the TOE reference, TOE overview and TOE
description to determine that they are consistent with each other.
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10.4
Conformance claims (ASE_CCL)
10.4.1
Evaluation of sub-activity (ASE_CCL.1)
10.4.1.1
Objectives
333
The objective of this sub-activity is to determine the validity of various
conformance claims. These describe how the ST and the TOE conform to the
CC and how the ST conforms to PPs and packages.
10.4.1.2
Input
334
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the PP(s) that the ST claims conformance to;
c)
the package(s) that the ST claims conformance to.
10.4.1.3
Action ASE_CCL.1.1E
ASE_CCL.1.1C
The conformance claim shall contain a CC conformance claim that
identifies the version of the CC to which the ST and the TOE claim
conformance.
ASE_CCL.1-1
The evaluator shall check that the conformance claim contains a CC
conformance claim that identifies the version of the CC to which the ST and
the TOE claim conformance.
335
The evaluator determines that the CC conformance claim identifies the
version of the CC that was used to develop this ST. This should include the
version number of the CC and, unless the International English version of the
CC was used, the language of the version of the CC that was used.
336
For a composed TOE, the evaluator will consider any differences between
the version of the CC claimed for a component and the version of the CC
claimed for the composed TOE. If the versions differ the evaluator will
assess whether the differences between the versions will lead to conflicting
claims.
337
For instances where the CC conformance claims for the base TOE and
dependent TOE are for different major releases of the CC (e.g. one
component TOE conformance claim is CC v2.x and the other component
TOE conformance claim is CC v3.x), the conformance claim for the
composed TOE will be the earlier release of the CC, as the CC is developed
with an aim to provide backwards compatibility (although this may not be
achieved in the strictest sense, it is understood to be achieved in principle).
ASE_CCL.1.2C
The CC conformance claim shall describe the conformance of the ST to
CC Part 2 as either CC Part 2 conformant or CC Part 2 extended.
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ASE_CCL.1-2
The evaluator shall check that the CC conformance claim states a claim of
either CC Part 2 conformant or CC Part 2 extended for the ST.
338
For a composed TOE, the evaluator will consider whether this claim is
consistent not only with the CC Part 2, but also with the claims of
conformance to CC Part 2 by each of the component TOEs. I.e. if one or
more component TOEs claims to be CC Part 2 extended, then the composed
TOE should also claim to be CC Part 2 extended.
339
The CC conformance claim for the composed TOE may be CC Part 2
extended, even though the component TOEs are Part 2 conformant, in the
event that additional SFRs are claimed for the base TOE (see composed TOE
guidance for ASE_CCL.1.6C)
ASE_CCL.1.3C
The CC conformance claim shall describe the conformance of the ST to
CC Part 3 as either CC Part 3 conformant or CC Part 3 extended.
ASE_CCL.1-3
The evaluator shall check that the CC conformance claim states a claim of
either CC Part 3 conformant or CC Part 3 extended for the ST.
ASE_CCL.1.4C
The CC conformance claim shall be consistent with the extended
components definition.
ASE_CCL.1-4
The evaluator shall examine the CC conformance claim for CC Part 2 to
determine that it is consistent with the extended components definition.
340
If the CC conformance claim contains CC Part 2 conformant, the evaluator
determines that the extended components definition does not define
functional components.
341
If the CC conformance claim contains CC Part 2 extended, the evaluator
determines that the extended components definition defines at least one
extended functional component.
ASE_CCL.1-5
The evaluator shall examine the CC conformance claim for CC Part 3 to
determine that it is consistent with the extended components definition.
342
If the CC conformance claim contains CC Part 3 conformant, the evaluator
determines that the extended components definition does not define
assurance components.
343
If the CC conformance claim contains CC Part 3 extended, the evaluator
determines that the extended components definition defines at least one
extended assurance component.
ASE_CCL.1.5C
The conformance claim shall identify all PPs and security requirement
packages to which the ST claims conformance.
ASE_CCL.1-6
The evaluator shall check that the conformance claim contains a PP claim
that identifies all PPs for which the ST claims conformance.
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344
If the ST does not claim conformance to a PP, this work unit is not
applicable and therefore considered to be satisfied.
345
The evaluator determines that any referenced PPs are unambiguously
identified (e.g. by title and version number, or by the identification included
in the introduction of that PP).
346
The evaluator is reminded that claims of partial conformance to a PP are not
permitted. Therefore, conformance to a PP requiring a composite solution
may be claimed in an ST for a composed TOE. Conformance to such a PP
would not have been possible during the evaluation of the component TOEs,
as these components would not have satisfied the composed solution. This is
only possible in the instances where the “composite” PP permits use of the
composition evaluation approach (use of ACO components).
347
The ST for a composed TOE will identify the STs of the component TOEs
from which the composed ST is comprised. The composed TOE is
essentially claiming conformance to the STs of the component TOEs.
ASE_CCL.1-7
The evaluator shall check that the conformance claim contains a package
claim that identifies all packages to which the ST claims conformance.
348
If the ST does not claim conformance to a package, this work unit is not
applicable and therefore considered to be satisfied.
349
The evaluator determines that any referenced packages are unambiguously
identified (e.g. by title and version number, or by the identification included
in the introduction of that package).
350
The evaluator determines that the component TOE STs from which the
composed TOE is derived are also unambiguously identified.
351
The evaluator is reminded that claims of partial conformance to a package
are not permitted.
ASE_CCL.1.6C
The conformance claim shall describe any conformance of the ST to a
package as either package-conformant or package-augmented.
ASE_CCL.1-8
The evaluator shall check that, for each identified package, the conformance
claim states a claim of either package-name conformant or package-name
augmented.
352
If the ST does not claim conformance to a package, this work unit is not
applicable and therefore considered to be satisfied.
353
If the package conformance claim contains package-name conformant, the
evaluator determines that:
a)
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If the package is an assurance package, then the ST contains all SARs
included in the package, but no additional SARs.
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b)
354
If the package is a functional package, then the ST contains all SFRs
included in the package, but no additional SFRs.
If the package conformance claim contains package-name augmented, the
evaluator determines that:
a)
If the package is an assurance package then the ST contains all SARs
included in the package, and at least one additional SAR or at least
one SAR that is hierarchical to a SAR in the package.
b)
If the package is a functional package, then the ST contains all SFRs
included in the package, and at least one additional SFR or at least
one SFR that is hierarchical to a SFR in the package.
ASE_CCL.1.7C
The conformance claim rationale shall demonstrate that the TOE type is
consistent with the TOE type in the PPs for which conformance is being
claimed.
ASE_CCL.1-9
The evaluator shall examine the conformance claim rationale to determine
that the TOE type of the TOE is consistent with all TOE types of the PPs.
355
If the ST does not claim conformance to a PP, this work unit is not
applicable and therefore considered to be satisfied.
356
The relation between the types may be simple: a firewall ST claiming
conformance to a firewall PP, or more complex: a smart card ST claiming
conformance to a number of PPs at the same time (a PP for the integrated
circuit, a PP for the smart card OS, and two PPs for two applications on the
smart card).
357
For a composed TOE, the evaluator will determine whether the conformance
claim rationale demonstrates that the TOE types of the component TOEs are
consistent with the composed TOE type. This does not mean that both the
component and the composed TOE types have to be the same, but rather that
the component TOEs are suitable for integration to provide the composed
TOE. It should be made clear in the composed TOE ST which SFRs are only
included as a result of composition, and were not examined as SFRs in the
base and dependent TOE (e.g. EALx) evaluation.
ASE_CCL.1.8C
The conformance claim rationale shall demonstrate that the statement of
the security problem definition is consistent with the statement of the
security problem definition in the PPs for which conformance is being
claimed.
ASE_CCL.1-10
The evaluator shall examine the conformance claim rationale to determine
that it demonstrates that the statement of security problem definition is
consistent, as defined by the conformance statement of the PP, with the
statements of security problem definition stated in the PPs to which
conformance is being claimed.
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358
If the ST does not claim conformance with a PP, this work unit is not
applicable and therefore considered to be satisfied.
359
If the PP does not have a statement of security problem definition, this work
unit is not applicable and therefore considered to be satisfied.
360
If strict conformance is required by the PP to which conformance is being
claimed no conformance claim rationale is required. Instead, the evaluator
determines whether:
a)
the threats in the ST are a superset of or identical to the threats in the
PP to which conformance is being claimed;
b)
the OSPs in the ST are a superset of or identical to the OSPs in the PP
to which conformance is being claimed;
c)
the assumptions in the ST are identical to the assumptions in the PP
to which conformance is being claimed;
361
If demonstrable conformance is required by the PP, the evaluator examines
the conformance claim rationale to determine that it demonstrates that the
statement of security problem definition of the ST is equivalent or more
restrictive than the statement of security problem definition in the PP to
which conformance is being claimed.
362
For guidance on “equivalent or more restrictive” see CC Part 1 Annex D, PP
conformance.
363
For a composed TOE, the evaluator will consider whether the security
problem definition of the composed TOE is consistent with that specified in
the STs for the component TOEs. This is determined in terms of
demonstrable conformance. In particular, the evaluator examines the
conformance claim rationale to determine that:
a)
Threat statements and OSPs in the composed TOE ST do not
contradict those from the component STs.
b)
Any assumptions made in the component STs are upheld in the
composed TOE ST. That is, either the assumption should also be
present in the composed ST, or the assumption should be positively
addressed in the composed ST. The assumption may be positively
addressed through specification of requirements in the composed
TOE to provide functionality fulfilling the concern captured in the
assumption.
ASE_CCL.1.9C
The conformance claim rationale shall demonstrate that the statement of
security objectives is consistent with the statement of security objectives in
the PPs for which conformance is being claimed.
ASE_CCL.1-11
The evaluator shall examine the conformance claim rationale to determine
that the statement of security objectives is consistent, as defined by the
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conformance statement of the PP, with the statement of security objectives in
the PPs.
364
If the ST does not claim conformance to a PP, this work unit is not
applicable and therefore considered to be satisfied.
365
If strict conformance is required by the PP, no conformance claim rationale
is required. Instead, the evaluator determines whether:
−
The ST contains all security objectives for the TOE of the PP to
which conformance is being claimed. Note that it is allowed for the
ST under evaluation to have additional security objectives for the
TOE;
−
The ST contains exactly all security objectives for the operational
environment (with one exception in the next bullet). Note that it is
not allowed for the ST under evaluation to have additional security
objectives for the operational environment;
−
The ST may specify that certain objectives for the operational
environment in the PP that conformance is being claimed to are
security objectives for the TOE in the ST. This is a valid exception to
the previous bullet.
366
If demonstrable conformance is required by the PP to which conformance is
being claimed, the evaluator examines the conformance claim rationale to
determine that it demonstrates that the statement of security objectives of the
ST is equivalent or more restrictive than the statement of security objectives
in the PP to which conformance is being claimed.
367
For guidance on “equivalent or more restrictive” see CC Part 1 Annex D, PP
conformance.
368
For a composed TOE, the evaluator will consider whether the security
objectives of the composed TOE are consistent with that specified in the STs
for the component TOEs. This is determined in terms of demonstrable
conformance. In particular, the evaluator examines the conformance claim
rationale to determine that:
a)
The statement of security objectives in the dependent TOE ST
relevant to any IT in the operational environment are consistent with
the statement of security objectives for the TOE in the base TOE ST.
It is not expected that the statement of security objectives for the
environment within in the dependent TOE ST will cover all aspects
of the statement of security objectives for the TOE in the base TOE
ST.
b)
The statement of security objectives in the composed ST is consistent
with the statements of security objectives in the STs for the
component TOEs.
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369
If demonstrable conformance is required by the PP, the evaluator examines
the conformance claim rationale to determine that it demonstrates that the
statement of security objectives of the ST is at least equivalent to the
statement of security objectives in the PP, or component TOE ST in the case
of a composed TOE ST.
ASE_CCL.1.10C
The conformance claim rationale shall demonstrate that the statement of
security requirements is consistent with the statement of security
requirements in the PPs for which conformance is being claimed.
ASE_CCL.1-12
The evaluator shall examine the ST to determine that it is consistent, as
defined by the conformance statement of the PP, with all security
requirements in the PPs for which conformance is being claimed.
370
If the ST does not claim conformance to a PP, this work unit is not
applicable and therefore considered to be satisfied.
371
If strict conformance is required by the PP to which conformance is being
claimed, no conformance claim rationale is required. Instead, the evaluator
determines whether the statement of security requirements in the ST is a
superset of or identical to the statement of security requirements in the PP to
which conformance is being claimed (for strict conformance).
372
If demonstrable conformance is required by the PP to which conformance is
being claimed, the evaluator examines the conformance claim rationale to
determine that it demonstrates that the statement of security requirements of
the ST is equivalent or more restrictive than the statement of security
requirements in the PP to which conformance is being claimed.
373
For guidance on “equivalent or more restrictive” see CC Part 1 Annex D, PP
conformance.
374
For a composed TOE, the evaluator will consider whether the security
requirements of the composed TOE are consistent with that specified in the
STs for the component TOEs. This is determined in terms of demonstrable
conformance. In particular, the evaluator examines the conformance
rationale to determine that:
a)
The statement of security requirements in the dependent TOE ST
relevant to any IT in the operational environment is consistent with
the statement of security requirements for the TOE in the base TOE
ST. It is not expected that the statement of security requirements for
the environment within in the dependent TOE ST will cover all
aspects of the statement of security requirements for the TOE in the
base TOE ST, as some SFRs may need to be added to the statement
of security requirements in the composed TOE ST. However, the
statement of security requirements in the base should support the
operation of the dependent component.
b)
The statement of security objectives in the dependent TOE ST
relevant to any IT in the operational environment is consistent with
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the statement of security requirements for the TOE in the base TOE
ST. It is not expected that the statement of security objectives for the
environment within in the dependent TOE ST will cover all aspects
of the statement of security requirements for the TOE in the base
TOE ST.
c)
375
The statement of security requirements in the composed is consistent
with the statements of security requirements in the STs for the
component TOEs.
If demonstrable conformance is required by the PP to which conformance is
being claimed, the evaluator examines the conformance claim rationale to
determine that it demonstrates that the statement of security requirements of
the ST is at least equivalent to the statement of security requirements in the
PP, or component TOE ST in the case of a composed TOE ST.
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10.5
Security problem definition (ASE_SPD)
10.5.1
Evaluation of sub-activity (ASE_SPD.1)
10.5.1.1
Objectives
376
The objective of this sub-activity is to determine that the security problem
intended to be addressed by the TOE and its operational environment is
clearly defined.
10.5.1.2
Input
377
The evaluation evidence for this sub-activity is:
a)
the ST.
10.5.1.3
Action ASE_SPD.1.1E
ASE_SPD.1.1C
The security problem definition shall describe the threats.
ASE_SPD.1-1
The evaluator shall check that the security problem definition describes the
threats.
378
If all security objectives are derived from assumptions and/or OSPs only, the
statement of threats need not be present in the ST. In this case, this work unit
is not applicable and therefore considered to be satisfied.
379
The evaluator determines that the security problem definition describes the
threats that must be countered by the TOE and/or operational environment.
ASE_SPD.1.2C
All threats shall be described in terms of a threat agent, an asset, and an
adverse action.
ASE_SPD.1-2
The evaluator shall examine the security problem definition to determine
that all threats are described in terms of a threat agent, an asset, and an
adverse action.
380
If all security objectives are derived from assumptions and/or OSPs only, the
statement of threats need not be present in the ST. In this case, this work unit
is not applicable and therefore considered to be satisfied.
381
Threat agents may be further described by aspects such as expertise,
resource, opportunity, and motivation.
ASE_SPD.1.3C
The security problem definition shall describe the OSPs.
ASE_SPD.1-3
The evaluator shall check that the security problem definition describes the
OSPs.
382
If all security objectives are derived from assumptions and threats only,
OSPs need not be present in the ST. In this case, this work unit is not
applicable and therefore considered to be satisfied.
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383
The evaluator determines that OSP statements are made in terms of rules or
guidelines that must be followed by the TOE and/or its operational
environment.
384
The evaluator determines that each OSP is explained and/or interpreted in
sufficient detail to make it clearly understandable; a clear presentation of
policy statements is necessary to permit tracing security objectives to them.
ASE_SPD.1.4C
The security problem definition shall describe the assumptions about the
operational environment of the TOE.
ASE_SPD.1-4
The evaluator shall examine the security problem definition to determine
that it describes the assumptions about the operational environment of the
TOE.
385
If there are no assumptions, this work unit is not applicable and is therefore
considered to be satisfied.
386
The evaluator determines that each assumption about the operational
environment of the TOE is explained in sufficient detail to enable consumers
to determine that their operational environment matches the assumption. If
the assumptions are not clearly understood, the end result may be that the
TOE is used in an operational environment in which it will not function in a
secure manner.
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10.6
Security objectives (ASE_OBJ)
10.6.1
Evaluation of sub-activity (ASE_OBJ.1)
10.6.1.1
Objectives
387
The objective of this sub-activity is to determine whether the security
objectives for the operational environment are clearly defined.
10.6.1.2
Input
388
The evaluation evidence for this sub-activity is:
a)
the ST.
10.6.1.3
Action ASE_OBJ.1.1E
ASE_OBJ.1.1C
The statement of security objectives shall describe the security objectives
for the operational environment.
ASE_OBJ.1-1
The evaluator shall check that the statement of security objectives defines
the security objectives for the operational environment.
389
The evaluator checks that the security objectives for the operational
environment are identified.
10.6.2
Evaluation of sub-activity (ASE_OBJ.2)
10.6.2.1
Objectives
390
The objective of this sub-activity is to determine whether the security
objectives adequately and completely address the security problem definition
and that the division of this problem between the TOE and its operational
environment is clearly defined.
10.6.2.2
Input
391
The evaluation evidence for this sub-activity is:
a)
the ST.
10.6.2.3
Action ASE_OBJ.2.1E
ASE_OBJ.2.1C
The statement of security objectives shall describe the security objectives
for the TOE and the security objectives for the operational environment.
ASE_OBJ.2-1
The evaluator shall check that the statement of security objectives defines
the security objectives for the TOE and the security objectives for the
operational environment.
392
The evaluator checks that both categories of security objectives are clearly
identified and separated from the other category.
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ASE_OBJ.2.2C
The security objectives rationale shall trace each security objective for the
TOE back to threats countered by that security objective and OSPs
enforced by that security objective.
ASE_OBJ.2-2
The evaluator shall check that the security objectives rationale traces all
security objectives for the TOE back to threats countered by the objectives
and/or OSPs enforced by the objectives.
393
Each security objective for the TOE may trace back to threats or OSPs, or a
combination of threats and OSPs, but it must trace back to at least one threat
or OSP.
394
Failure to trace implies that either the security objectives rationale is
incomplete, the security problem definition is incomplete, or the security
objective for the TOE has no useful purpose.
ASE_OBJ.2.3C
The security objectives rationale shall trace each security objective for the
operational environment back to threats countered by that security
objective, OSPs enforced by that security objective, and assumptions
upheld by that security objective.
ASE_OBJ.2-3
The evaluator shall check that the security objectives rationale traces the
security objectives for the operational environment back to threats countered
by that security objective, to OSPs enforced by that security objective, and to
assumptions upheld by that security objective.
395
Each security objective for the operational environment may trace back to
threats, OSPs, assumptions, or a combination of threats, OSPs and/or
assumptions, but it must trace back to at least one threat, OSP or assumption.
396
Failure to trace implies that either the security objectives rationale is
incomplete, the security problem definition is incomplete, or the security
objective for the operational environment has no useful purpose.
ASE_OBJ.2.4C
The security objectives rationale shall demonstrate that the security
objectives counter all threats.
ASE_OBJ.2-4
The evaluator shall examine the security objectives rationale to determine
that it justifies for each threat that the security objectives are suitable to
counter that threat.
397
If no security objectives trace back to the threat, this work unit fails.
398
The evaluator determines that the justification for a threat shows whether the
threat is removed, diminished or mitigated.
399
The evaluator determines that the justification for a threat demonstrates that
the security objectives are sufficient: if all security objectives that trace back
to the threat are achieved, the threat is removed, sufficiently diminished, or
the effects of the threat are sufficiently mitigated.
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400
Note that the tracings from security objectives to threats provided in the
security objectives rationale may be part of a justification, but do not
constitute a justification by themselves. Even in the case that a security
objective is merely a statement reflecting the intent to prevent a particular
threat from being realised, a justification is required, but this justification
may be as minimal as “Security Objective X directly counters Threat Y”.
401
The evaluator also determines that each security objective that traces back to
a threat is necessary: when the security objective is achieved it actually
contributes to the removal, diminishing or mitigation of that threat.
ASE_OBJ.2.5C
The security objectives rationale shall demonstrate that the security
objectives enforce all OSPs.
ASE_OBJ.2-5
The evaluator shall examine the security objectives rationale to determine
that for each OSP it justifies that the security objectives are suitable to
enforce that OSP.
402
If no security objectives trace back to the OSP, this work unit fails.
403
The evaluator determines that the justification for an OSP demonstrates that
the security objectives are sufficient: if all security objectives that trace back
to that OSP are achieved, the OSP is enforced.
404
The evaluator also determines that each security objective that traces back to
an OSP is necessary: when the security objective is achieved it actually
contributes to the enforcement of the OSP.
405
Note that the tracings from security objectives to OSPs provided in the
security objectives rationale may be part of a justification, but do not
constitute a justification by themselves. In the case that a security objective is
merely a statement reflecting the intent to enforce a particular OSP, a
justification is required, but this justification may be as minimal as “Security
Objective X directly enforces OSP Y”.
ASE_OBJ.2.6C
The security objectives rationale shall demonstrate that the security
objectives for the operational environment uphold all assumptions.
ASE_OBJ.2-6
The evaluator shall examine the security objectives rationale to determine
that for each assumption for the operational environment it contains an
appropriate justification that the security objectives for the operational
environment are suitable to uphold that assumption.
406
If no security objectives for the operational environment trace back to the
assumption, this work unit fails.
407
The evaluator determines that the justification for an assumption about the
operational environment of the TOE demonstrates that the security objectives
are sufficient: if all security objectives for the operational environment that
trace back to that assumption are achieved, the operational environment
upholds the assumption.
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408
The evaluator also determines that each security objective for the operational
environment that traces back to an assumption about the operational
environment of the TOE is necessary: when the security objective is
achieved it actually contributes to the operational environment upholding the
assumption.
409
Note that the tracings from security objectives for the operational
environment to assumptions provided in the security objectives rationale may
be a part of a justification, but do not constitute a justification by themselves.
Even in the case that a security objective of the operational environment is
merely a restatement of an assumption, a justification is required, but this
justification may be as minimal as “Security Objective X directly upholds
Assumption Y”.
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10.7
Extended components definition (ASE_ECD)
10.7.1
Evaluation of sub-activity (ASE_ECD.1)
10.7.1.1
Objectives
410
The objective of this sub-activity is to determine whether extended
components have been clearly and unambiguously defined, and whether they
are necessary, i.e. they may not be clearly expressed using existing CC Part 2
or CC Part 3 components.
10.7.1.2
Input
411
The evaluation evidence for this sub-activity is:
a)
the ST.
10.7.1.3
Action ASE_ECD.1.1E
ASE_ECD.1.1C
The statement of security requirements shall identify all extended security
requirements.
ASE_ECD.1-1
The evaluator shall check that all security requirements in the statement of
security requirements that are not identified as extended requirements are
present in CC Part 2 or in CC Part 3.
ASE_ECD.1.2C
The extended components definition shall define an extended component
for each extended security requirement.
ASE_ECD.1-2
The evaluator shall check that the extended components definition defines
an extended component for each extended security requirement.
412
If the ST does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
413
A single extended component may be used to define multiple iterations of an
extended security requirement, it is not necessary to repeat this definition for
each iteration.
ASE_ECD.1.3C
The extended components definition shall describe how each extended
component is related to the existing CC components, families, and classes.
ASE_ECD.1-3
The evaluator shall examine the extended components definition to
determine that it describes how each extended component fits into the
existing CC components, families, and classes.
414
If the ST does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
415
The evaluator determines that each extended component is either:
a)
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b)
a member of a new family defined in the ST.
416
If the extended component is a member of an existing CC Part 2 or CC Part 3
family, the evaluator determines that the extended components definition
adequately describes why the extended component should be a member of
that family and how it relates to other components of that family.
417
If the extended component is a member of a new family defined in the ST,
the evaluator confirms that the extended component is not appropriate for an
existing family.
418
If the ST defines new families, the evaluator determines that each new family
is either:
a)
a member of an existing CC Part 2 or CC Part 3 class, or
b)
a member of a new class defined in the ST.
419
If the family is a member of an existing CC Part 2 or CC Part 3 class, the
evaluator determines that the extended components definition adequately
describes why the family should be a member of that class and how it relates
to other families in that class.
420
If the family is a member of a new class defined in the ST, the evaluator
confirms that the family is not appropriate for an existing class.
ASE_ECD.1-4
The evaluator shall examine the extended components definition to
determine that each definition of an extended component identifies all
applicable dependencies of that component.
421
If the ST does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
422
The evaluator confirms that no applicable dependencies have been
overlooked by the ST author.
ASE_ECD.1.4C
The extended components definition shall use the existing CC components,
families, classes, and methodology as a model for presentation.
ASE_ECD.1-5
The evaluator shall examine the extended components definition to
determine that each extended functional component uses the existing CC Part
2 components as a model for presentation.
423
If the ST does not contain extended SFRs, this work unit is not applicable
and therefore considered to be satisfied.
424
The evaluator determines that the extended functional component is
consistent with CC Part 2 Section 7.1.3, Component structure.
425
If the extended functional component uses operations, the evaluator
determines that the extended functional component is consistent with CC
Part 1 Annex C.4, Operations.
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426
If the extended functional component is hierarchical to an existing functional
component, the evaluator determines that the extended functional component
is consistent with CC Part 2 Section 7.2.1, Component changes highlighting.
ASE_ECD.1-6
The evaluator shall examine the extended components definition to
determine that each definition of a new functional family uses the existing
CC functional families as a model for presentation.
427
If the ST does not define new functional families, this work unit is not
applicable and therefore considered to be satisfied.
428
The evaluator determines that all new functional families are defined
consistent with CC Part 2 Section 7.1.2, Family structure.
ASE_ECD.1-7
The evaluator shall examine the extended components definition to
determine that each definition of a new functional class uses the existing CC
functional classes as a model for presentation.
429
If the ST does not define new functional classes, this work unit is not
applicable and therefore considered to be satisfied.
430
The evaluator determines that all new functional classes are defined
consistent with CC Part 2 Section 7.1.1, Class structure.
ASE_ECD.1-8
The evaluator shall examine the extended components definition to
determine that each definition of an extended assurance component uses the
existing CC Part 3 components as a model for presentation.
431
If the ST does not contain extended SARs, this work unit is not applicable
and therefore considered to be satisfied.
432
The evaluator determines that the extended assurance component definition
is consistent with CC Part 3 Section 7.1.3, Assurance component structure.
433
If the extended assurance component uses operations, the evaluator
determines that the extended assurance component is consistent with CC Part
1 Section Annex C.4, Operations.
434
If the extended assurance component is hierarchical to an existing assurance
component, the evaluator determines that the extended assurance component
is consistent with CC Part 3 Section 7.1.3, Assurance component structure.
ASE_ECD.1-9
The evaluator shall examine the extended components definition to
determine that, for each defined extended assurance component, applicable
methodology has been provided.
435
If the ST does not contain extended SARs, this work unit is not applicable
and therefore considered to be satisfied.
436
The evaluator determines that, for each evaluator action element of each
extended SAR, one or more work units are provided and that successfully
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performing all work units for a given evaluator action element will
demonstrate that the element has been achieved.
ASE_ECD.1-10
The evaluator shall examine the extended components definition to
determine that each definition of a new assurance family uses the existing
CC assurance families as a model for presentation.
437
If the ST does not define new assurance families, this work unit is not
applicable and therefore considered to be satisfied.
438
The evaluator determines that all new assurance families are defined
consistent with CC Part 3 Section 7.1.2, Assurance family structure.
ASE_ECD.1-11
The evaluator shall examine the extended components definition to
determine that each definition of a new assurance class uses the existing CC
assurance classes as a model for presentation.
439
If the ST does not define new assurance classes, this work unit is not
applicable and therefore considered to be satisfied.
440
The evaluator determines that all new assurance classes are defined
consistent with CC Part 3 Section 7.1.1, Assurance class structure.
ASE_ECD.1.5C
The extended components shall consist of measurable and objective
elements such that conformance or nonconformance to these elements can
be demonstrated.
ASE_ECD.1-12
The evaluator shall examine the extended components definition to
determine that each element in each extended component is measurable and
states objective evaluation requirements, such that conformance or
nonconformance can be demonstrated.
441
If the ST does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
442
The evaluator determines that elements of extended functional components
are stated in such a way that they are testable, and traceable through the
appropriate TSF representations.
443
The evaluator also determines that elements of extended assurance
components avoid the need for subjective evaluator judgement.
444
The evaluator is reminded that whilst being measurable and objective is
appropriate for all evaluation criteria, it is acknowledged that no formal
method exists to prove such properties. Therefore the existing CC functional
and assurance components are to be used as a model for determining what
constitutes conformance with this requirement.
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10.7.1.4
Action ASE_ECD.1.2E
ASE_ECD.1-13
The evaluator shall examine the extended components definition to
determine that each extended component can not be clearly expressed using
existing components.
445
If the ST does not contain extended security requirements, this work unit is
not applicable and therefore considered to be satisfied.
446
The evaluator should take components from CC Part 2 and CC Part 3, other
extended components that have been defined in the ST, combinations of
these components, and possible operations on these components into account
when making this determination.
447
The evaluator is reminded that the role of this work unit is to preclude
unnecessary duplication of components, that is, components that may be
clearly expressed by using other components. The evaluator should not
undertake an exhaustive search of all possible combinations of components
including operations in an attempt to find a way to express the extended
component by using existing components.
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10.8
Security requirements (ASE_REQ)
10.8.1
Evaluation of sub-activity (ASE_REQ.1)
10.8.1.1
Objectives
448
The objective of this sub-activity is to determine whether the SFRs and
SARs are clear, unambiguous and well-defined and whether they are
internally consistent.
10.8.1.2
Input
449
The evaluation evidence for this sub-activity is:
a)
the ST.
10.8.1.3
Action ASE_REQ.1.1E
ASE_REQ.1.1C
The statement of security requirements shall describe the SFRs and the
SARs.
ASE_REQ.1-1
The evaluator shall check that the statement of security requirements
describes the SFRs.
450
The evaluator determines that each SFR is identified by one of the following
means:
a)
by reference to an individual component in CC Part 2;
b)
by reference to an extended component in the extended components
definition of the ST;
c)
by reference to a PP that the ST claims to be conformant with;
d)
by reference to a security requirements package that the ST claims to
be conformant with;
e)
by reproduction in the ST.
451
It is not required to use the same means of identification for all SFRs.
ASE_REQ.1-2
The evaluator shall check that the statement of security requirements
describes the SARs.
452
The evaluator determines that each SAR is identified by one of the following
means:
a)
by reference to an individual component in CC Part 3;
b)
by reference to an extended component in the extended components
definition of the ST;
c)
by reference to a PP that the ST claims to be conformant with;
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d)
by reference to a security requirements package that the ST claims to
be conformant with;
e)
by reproduction in the ST.
453
It is not required to use the same means of identification for all SARs.
ASE_REQ.1.2C
All subjects, objects, operations, security attributes, external entities and
other terms that are used in the SFRs and the SARs shall be defined.
ASE_REQ.1-3
The evaluator shall examine the ST to determine that all subjects, objects,
operations, security attributes, external entities and other terms that are used
in the SFRs and the SARs are defined.
454
The evaluator determines that the ST defines all:
−
(types of) subjects and objects that are used in the SFRs;
−
(types of) security attributes of subjects, users, objects, information,
sessions and/or resources, possible values that these attributes may
take and any relations between these values (e.g. top_secret is
“higher” than secret);
−
(types of) operations that are used in the SFRs, including the effects
of these operations;
−
(types of) external entities in the SFRs;
−
other terms that are introduced in the SFRs and/or SARs by
completing operations, if these terms are not immediately clear, or
are used outside their dictionary definition.
455
The goal of this work unit is to ensure that the SFRs and SARs are welldefined and that no misunderstanding may occur due to the introduction of
vague terms. This work unit should not be taken into extremes, by forcing
the ST writer to define every single word. The general audience of a set of
security requirements should be assumed to have a reasonable knowledge of
IT, security and Common Criteria.
456
All of the above may be presented in groups, classes, roles, types or other
groupings or characterisations that allow easy understanding.
457
The evaluator is reminded that these lists and definitions do not have to be
part of the statement of security requirements, but may be placed (in part or
in whole) in different sections. This may be especially applicable if the same
terms are used in the rest of the ST.
ASE_REQ.1.3C
The statement of security requirements shall identify all operations on the
security requirements.
ASE_REQ.1-4
The evaluator shall check that the statement of security requirements
identifies all operations on the security requirements.
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458
The evaluator determines that all operations are identified in each SFR or
SAR where such an operation is used. Identification may be achieved by
typographical distinctions, or by explicit identification in the surrounding
text, or by any other distinctive means.
ASE_REQ.1.4C
All operations shall be performed correctly.
ASE_REQ.1-5
The evaluator shall examine the statement of security requirements to
determine that all assignment operations are performed correctly.
459
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.1-6
The evaluator shall examine the statement of security requirements to
determine that all iteration operations are performed correctly.
460
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.1-7
The evaluator shall examine the statement of security requirements to
determine that all selection operations are performed correctly.
461
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.1-8
The evaluator shall examine the statement of security requirements to
determine that all refinement operations are performed correctly.
462
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.1.5C
Each dependency of the security requirements shall either be satisfied, or
the security requirements rationale shall justify the dependency not being
satisfied.
ASE_REQ.1-9
The evaluator shall examine the statement of security requirements to
determine that each dependency of the security requirements is either
satisfied, or that a security requirements rationale is provided which justifies
the dependency not being satisfied.
463
A dependency is satisfied by the inclusion of the relevant component (or one
that is hierarchical to it) within the statement of security requirements. The
component used to satisfy the dependency should, if necessary, be modified
by operations to ensure that it actually satisfies that dependency.
464
A justification that a dependency is not met should address either:
a)
why the dependency is not necessary or useful, in which case no
further information is required; or
b)
that the dependency has been addressed by the operational
environment of the TOE, in which case the justification should
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describe how the security objectives for the operational environment
address this dependency.
ASE_REQ.1.6C
The statement of security requirements shall be internally consistent.
ASE_REQ.1-10
The evaluator shall examine the statement of security requirements to
determine that it is internally consistent.
465
The evaluator determines that the combined set of all SFRs and SARs is
internally consistent.
466
The evaluator determines that on all occasions where different security
requirements apply to the same types of developer evidence, events,
operations, data, tests to be performed etc. or to “all objects”, “all subjects”
etc., that these requirements do not conflict.
467
Some possible conflicts are:
a)
an extended SAR specifying that the design of a certain
cryptographic algorithm is to be kept secret, and another extended
SAR specifying an open source review;
b)
FAU_GEN.1 Audit data generation specifying that subject identity is
to be logged, FDP_ACC.1 Subset access control specifying who has
access to these logs, and FPR_UNO.1 Unobservability specifying
that some actions of subjects should be unobservable to other
subjects. If the subject that should not be able to see an activity may
access logs of this activity, these SFRs conflict;
c)
FDP_RIP.1 Subset residual information protection specifying
deletion of information no longer needed, and FDP_ROL.1 Basic
rollback specifying that a TOE may return to a previous state. If the
information that is needed for the rollback to the previous state has
been deleted, these requirements conflict;
d)
Multiple iterations of FDP_ACC.1 Subset access control especially
where some iterations cover the same subjects, objects, or operations.
If one access control SFR allows a subject to perform an operation on
an object, while another access control SFR does not allow this, these
requirements conflict.
10.8.2
Evaluation of sub-activity (ASE_REQ.2)
10.8.2.1
Objectives
468
The objective of this sub-activity is to determine whether the SFRs and
SARs are clear, unambiguous and well-defined, whether they are internally
consistent, and whether the SFRs meet the security objectives of the TOE.
10.8.2.2
Input
469
The evaluation evidence for this sub-activity is:
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a)
the ST.
10.8.2.3
Action ASE_REQ.2.1E
ASE_REQ.2.1C
The statement of security requirements shall describe the SFRs and the
SARs.
ASE_REQ.2-1
The evaluator shall check that the statement of security requirements
describes the SFRs.
470
The evaluator determines that each SFRs is identified by one of the
following means:
a)
by reference to an individual component in CC Part 2;
b)
by reference to an extended component in the extended components
definition of the ST;
c)
by reference to an individual component in a PP that the ST claims to
be conformant with;
d)
by reference to an individual component in a security requirements
package that the ST claims to be conformant with;
e)
by reproduction in the ST.
471
It is not required to use the same means of identification for all SFRs.
ASE_REQ.2-2
The evaluator shall check that the statement of security requirements
describes the SARs.
472
The evaluator determines that all SARs are identified by one of the following
means:
a)
by reference to an individual component in CC Part 3;
b)
by reference to an extended component in the extended components
definition of the ST;
c)
by reference to an individual component in a PP that the ST claims to
be conformant with;
d)
by reference to an individual component in a security requirements
package that the ST claims to be conformant with;
e)
by reproduction in the ST.
473
It is not required to use the same means of identification for all SARs.
ASE_REQ.2.2C
All subjects, objects, operations, security attributes, external entities and
other terms that are used in the SFRs and the SARs shall be defined.
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ASE_REQ.2-3
The evaluator shall examine the ST to determine that all subjects, objects,
operations, security attributes, external entities and other terms that are used
in the SFRs and the SARs are defined.
474
The evaluator determines that the ST defines all:
−
(types of) subjects and objects that are used in the SFRs;
−
(types of) security attributes of subjects, users, objects, information,
sessions and/or resources, possible values that these attributes may
take and any relations between these values (e.g. top_secret is
“higher” than secret);
−
(types of) operations that are used in the SFRs, including the effects
of these operations;
−
(types of) external entities in the SFRs;
−
other terms that are introduced in the SFRs and/or SARs by
completing operations, if these terms are not immediately clear, or
are used outside their dictionary definition.
475
The goal of this work unit is to ensure that the SFRs and SARs are welldefined and that no misunderstanding may occur due to the introduction of
vague terms. This work unit should not be taken into extremes, by forcing
the ST writer to define every single word. The general audience of a set of
security requirements should be assumed to have a reasonable knowledge of
IT, security and Common Criteria.
476
All of the above may be presented in groups, classes, roles, types or other
groupings or characterisations that allow easy understanding.
477
The evaluator is reminded that these lists and definitions do not have to be
part of the statement of security requirements, but may be placed (in part or
in whole) in different sections. This may be especially applicable if the same
terms are used in the rest of the ST.
ASE_REQ.2.3C
The statement of security requirements shall identify all operations on the
security requirements.
ASE_REQ.2-4
The evaluator shall check that the statement of security requirements
identifies all operations on the security requirements.
478
The evaluator determines that all operations are identified in each SFR or
SAR where such an operation is used. Identification may be achieved by
typographical distinctions, or by explicit identification in the surrounding
text, or by any other distinctive means.
ASE_REQ.2.4C
All operations shall be performed correctly.
ASE_REQ.2-5
The evaluator shall examine the statement of security requirements to
determine that all assignment operations are performed correctly.
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479
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.2-6
The evaluator shall examine the statement of security requirements to
determine that all iteration operations are performed correctly.
480
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.2-7
The evaluator shall examine the statement of security requirements to
determine that all selection operations are performed correctly.
481
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.2-8
The evaluator shall examine the statement of security requirements to
determine that all refinement operations are performed correctly.
482
Guidance on the correct performance of operations may be found in CC Part
1 Annex Annex C.4, Operations.
ASE_REQ.2.5C
Each dependency of the security requirements shall either be satisfied, or
the security requirements rationale shall justify the dependency not being
satisfied.
ASE_REQ.2-9
The evaluator shall examine the statement of security requirements to
determine that each dependency of the security requirements is either
satisfied, or that the security requirements rationale justifies the dependency
not being satisfied.
483
A dependency is satisfied by the inclusion of the relevant component (or one
that is hierarchical to it) within the statement of security requirements. The
component used to satisfy the dependency should, if necessary, be modified
by operations to ensure that it actually satisfies that dependency.
484
A justification that a dependency is not met should address either:
a)
why the dependency is not necessary or useful, in which case no
further information is required; or
b)
that the dependency has been addressed by the operational
environment of the TOE, in which case the justification should
describe how the security objectives for the operational environment
address this dependency.
ASE_REQ.2.6C
The security requirements rationale shall trace each SFR back to the
security objectives for the TOE.
ASE_REQ.2-10
The evaluator shall check that the security requirements rationale traces each
SFR back to the security objectives for the TOE.
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485
The evaluator determines that each SFR is traced back to at least one security
objective for the TOE.
486
Failure to trace implies that either the security requirements rationale is
incomplete, the security objectives for the TOE are incomplete, or the SFR
has no useful purpose.
ASE_REQ.2.7C
The security requirements rationale shall demonstrate that the SFRs meet
all security objectives for the TOE.
ASE_REQ.2-11
The evaluator shall examine the security requirements rationale to determine
that for each security objective for the TOE it demonstrates that the SFRs are
suitable to meet that security objective for the TOE.
487
If no SFRs trace back to the security objective for the TOE, this work unit
fails.
488
The evaluator determines that the justification for a security objective for the
TOE demonstrates that the SFRs are sufficient: if all SFRs that trace back to
the objective are satisfied, the security objective for the TOE is achieved.
489
The evaluator also determines that each SFR that traces back to a security
objective for the TOE is necessary: when the SFR is satisfied, it actually
contributes to achieving the security objective.
490
Note that the tracings from SFRs to security objectives for the TOE provided
in the security requirements rationale may be a part of the justification, but
do not constitute a justification by themselves.
ASE_REQ.2.8C
The security requirements rationale shall explain why the SARs were
chosen.
ASE_REQ.2-12
The evaluator shall check that the security requirements rationale explains
why the SARs were chosen.
491
The evaluator is reminded that any explanation is correct, as long as it is
coherent and neither the SARs nor the explanation have obvious
inconsistencies with the remainder of the PP.
492
An example of an obvious inconsistency between the SARs and the
remainder of the PP would be to have threat agents that are very capable, but
an AVA_VAN SAR that does not protect against these threat agents.
ASE_REQ.2.9C
The statement of security requirements shall be internally consistent.
ASE_REQ.2-13
The evaluator shall examine the statement of security requirements to
determine that it is internally consistent.
493
The evaluator determines that the combined set of all SFRs and SARs is
internally consistent.
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494
The evaluator determines that on all occasions where different security
requirements apply to the same types of developer evidence, events,
operations, data, tests to be performed etc. or to “all objects”, “all subjects”
etc., that these requirements do not conflict.
495
Some possible conflicts are:
a)
an extended SAR specifying that the design of a certain
cryptographic algorithm is to be kept secret, and another extended
assurance requirement specifying an open source review;
b)
FAU_GEN.1 Audit data generation specifying that subject identity is
to be logged, FDP_ACC.1 Subset access control specifying who has
access to these logs, and FPR_UNO.1 Unobservability specifying
that some actions of subjects should be unobservable to other
subjects. If the subject that should not be able to see an activity may
access logs of this activity, these SFRs conflict;
c)
FDP_RIP.1 Subset residual information protection specifying
deletion of information no longer needed, and FDP_ROL.1 Basic
rollback specifying that a TOE may return to a previous state. If the
information that is needed for the rollback to the previous state has
been deleted, these requirements conflict;
d)
Multiple iterations of FDP_ACC.1 Subset access control especially
where some iterations cover the same subjects, objects, or operations.
If one access control SFR allows a subject to perform an operation on
an object, while another access control SFR does not allow this, these
requirements conflict.
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10.9
TOE summary specification (ASE_TSS)
10.9.1
Evaluation of sub-activity (ASE_TSS.1)
10.9.1.1
Objectives
496
The objective of this sub-activity is to determine whether the TOE summary
specification addresses all SFRs, and whether the TOE summary
specification is consistent with other narrative descriptions of the TOE.
10.9.1.2
Input
497
The evaluation evidence for this sub-activity is:
a)
the ST.
10.9.1.3
Action ASE_TSS.1.1E
ASE_TSS.1.1C
The TOE summary specification shall describe how the TOE meets each
SFR.
ASE_TSS.1-1
The evaluator shall examine the TOE summary specification to determine
that it describes how the TOE meets each SFR.
498
The evaluator determines that the TOE summary specification provides, for
each SFR from the statement of security requirements, a description on how
that SFR is met.
499
The evaluator is reminded that the objective of each description is to provide
potential consumers of the TOE with a high-level view of how the developer
intends to satisfy each SFR and that the descriptions therefore should not be
overly detailed.
500
For a composed TOE, the evaluator also determines that it is clear which
component provides each SFR or how the components combine to meet each
SFR.
10.9.1.4
Action ASE_TSS.1.2E
ASE_TSS.1-2
The evaluator shall examine the TOE summary specification to determine
that it is consistent with the TOE overview and the TOE description.
501
The TOE overview, TOE description, and TOE summary specification
describe the TOE in a narrative form at increasing levels of detail. These
descriptions therefore need to be consistent.
10.9.2
Evaluation of sub-activity (ASE_TSS.2)
10.9.2.1
Objectives
502
The objective of this sub-activity is to determine whether the TOE summary
specification addresses all SFRs, whether the TOE summary specification
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addresses interference, logical tampering and bypass, and whether the TOE
summary specification is consistent with other narrative descriptions of the
TOE.
10.9.2.2
Input
503
The evaluation evidence for this sub-activity is:
a)
the ST.
10.9.2.3
Action ASE_TSS.2.1E
ASE_TSS.2.1C
The TOE summary specification shall describe how the TOE meets each
SFR.
ASE_TSS.2-1
The evaluator shall examine the TOE summary specification to determine
that it describes how the TOE meets each SFR.
504
The evaluator determines that the TOE summary specification provides, for
each SFR from the statement of security requirements, a description on how
that SFR is met.
505
The evaluator is reminded that the objective of each description is to provide
potential consumers of the TOE with a high-level view of how the developer
intends to satisfy each SFR and that the descriptions therefore should not be
overly detailed.
506
For a composed TOE, the evaluator also determines that it is clear which
component provides each SFR or how the components combine to meet each
SFR.
ASE_TSS.2.2C
The TOE summary specification shall describe how the TOE protects itself
against interference and logical tampering.
ASE_TSS.2-2
The evaluator shall examine the TOE summary specification to determine
that it describes how the TOE protects itself against interference and logical
tampering.
507
The evaluator is reminded that the objective of each description is to provide
potential consumers of the TOE with a high-level view of how the developer
intends to provide protection against interference and logical tampering and
that the descriptions therefore should not be overly detailed.
508
For a composed TOE, the evaluator also determines that it is clear which
component provides the protection or how the components combine to
provide protection.
ASE_TSS.2.3C
The TOE summary specification shall describe how the TOE protects itself
against bypass.
ASE_TSS.2-3
The evaluator shall examine the TOE summary specification to determine
that it describes how the TOE protects itself against bypass.
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509
The evaluator is reminded that the objective of each description is to provide
potential consumers of the TOE with a high-level view of how the developer
intends to provide protection against bypass and that the descriptions
therefore should not be overly detailed.
510
For a composed TOE, the evaluator also determines that it is clear which
component provides the protection or how the components combine to
provide protection.
10.9.2.4
Action ASE_TSS.2.2E
ASE_TSS.2-4
The evaluator shall examine the TOE summary specification to determine
that it is consistent with the TOE overview and the TOE description.
511
The TOE overview, TOE description, and TOE summary specification
describe the TOE in a narrative form at increasing levels of detail. These
descriptions therefore need to be consistent.
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11
Class ADV: Development
11.1
Introduction
512
The purpose of the development activity is to assess the design
documentation in terms of its adequacy to understand how the TSF meets the
SFRs and how the implementation of these SFRs cannot be tampered with or
bypassed. This understanding is achieved through examination of
increasingly refined descriptions of the TSF design documentation. Design
documentation consists of a functional specification (which describes the
interfaces of the TSF), a TOE design description (which describes the
architecture of the TSF in terms of how it works in order to perform the
functions related to the SFRs being claimed), and an implementation
description (a source code level description). In addition, there is a security
architecture description (which describes the architectural properties of the
TSF to explain how its security enforcement cannot be compromised or
bypassed), an internals description (which describes how the TSF was
constructed in a manner that encourages understandability), and a security
policy model (which formally describes the security policies enforced by the
TSF).
11.2
Application notes
513
The CC requirements for design documentation are levelled by the amount,
and detail of information provided, and the degree of formality of the
presentation of the information. At lower levels, the most security-critical
portions of the TSF are described with the most detail, while less securitycritical portions of the TSF are merely summarised; added assurance is
gained by increasing the amount of information about the most securitycritical portions of the TSF, and increasing the details about the less securitycritical portions. The most assurance is achieved when thorough details and
information of all portions are provided.
514
The CC considers a document's degree of formality (that is, whether it is
informal or semiformal) to be hierarchical. An informal document is one that
is expressed in a natural language. The methodology does not dictate the
specific language that must be used; that issue is left for the scheme. The
following paragraphs differentiate the contents of the different informal
documents.
515
A functional specification provides a description of the purpose and methodof-use of interfaces to the TSF. For example, if an operating system presents
the user with a means of self-identification, of creating files, of modifying or
deleting files, of setting permissions defining what other users may access
files, and of communicating with remote machines, its functional
specification would contain descriptions of each of these and how they are
realised through interactions with the externally-visible interfaces to the TSF.
If there is also audit functionality that detects and record the occurrences of
such events, descriptions of this audit functionality would also be expected to
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be part of the functional specification; while this functionality is technically
not directly invoked by the user at the external interface, it certainly is
affected by what occurs at the user's external interface.
516
A design description is expressed in terms of logical divisions (subsystems
or components) that each provide a comprehensible service or function. For
example, a firewall might be composed of subsystems that deal with packet
filtering, with remote administration, with auditing, and with connectionlevel filtering. The design description of the firewall would describe the
actions that are taken, in terms of what actions each subsystem takes when an
incoming packet arrives at the firewall.
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11.3
Security Architecture (ADV_ARC)
11.3.1
Evaluation of sub-activity (ADV_ARC.1)
11.3.1.1
Objectives
517
The objective of this sub-activity is to determine whether the TSF is
structured such that it cannot be tampered with or bypassed, and whether
TSFs that provide security domains isolate those domains from each other.
11.3.1.2
Input
518
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the implementation representation (if available);
f)
the operational user guidance;
11.3.1.3
Application notes
519
The notions of self-protection, domain separation, and non-bypassability are
distinct from security functionality expressed in Part 2 SFRs because selfprotection and non-bypassability largely have no directly observable
interface at the TSF. Rather, they are properties of the TSF that are achieved
through the design of the TOE, and enforced by the correct implementation
of that design. Also, the evaluation of these properties is less straight-forward
than the evaluation of mechanisms; it is more difficult to check for the
absence of functionality than for its presence. However, the determination
that these properties are being satisfied is just as critical as the determination
that the mechanisms are properly implemented.
520
The overall approach used is that the developer provides a TSF that meets
the above-mentioned properties, and provides evidence (in the form of
documentation) that can be analysed to show that the properties are indeed
met. The evaluator has the responsibility for looking at the evidence and,
coupled with other evidence delivered for the TOE, determining that the
properties are achieved. The work units can be characterised as those
detailing with what information has to be provided, and those dealing with
the actual analysis the evaluator performs.
521
The security architecture description describes how domains are defined and
how the TSF keeps them separate. It describes what prevents untrusted
processes from getting to the TSF and modifying it. It describes what ensures
that all resources under the TSF's control are adequately protected and that
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all actions related to the SFRs are mediated by the TSF. It explains any role
the environment plays in any of these (e.g. presuming it gets correctly
invoked by its underlying environment, how is its security functionality
invoked?). In short, it explains how the TOE is considered to be providing
any kind of security service.
522
The analyses the evaluator performs must be done in the context of all of the
development evidence provided for the TOE, at the level of detail the
evidence is provided. At lower assurance levels there should not be the
expectation that, for example, TSF self-protection is completely analysed,
because only high-level design representations will be available. The
evaluator also needs to be sure to use information gleaned from other
portions of their analysis (e.g., analysis of the TOE design) in making their
assessments for the properties being examined in the following work units.
11.3.1.4
Action ADV_ARC.1.1E
ADV_ARC.1.1C
The security architecture description shall be at a level of detail
commensurate with the description of the SFR-enforcing abstractions
described in the TOE design document.
ADV_ARC.1-1
The evaluator shall examine the security architecture description to
determine that the information provided in the evidence is presented at a
level of detail commensurate with the descriptions of the SFR-enforcing
abstractions contained in the functional specification and TOE design
document.
523
With respect to the functional specification, the evaluator should ensure that
the self-protection functionality described cover those effects that are evident
at the TSFI. Such a description might include protection placed upon the
executable images of the TSF, and protection placed on objects (e.g., files
used by the TSF). The evaluator ensures that the functionality that might be
invoked through the TSFI is described.
524
If Evaluation of sub-activity (ADV_TDS.1) or Evaluation of sub-activity
(ADV_TDS.2) is included, the evaluator ensures the security architecture
description contains information on how any subsystems that contribute to
TSF domain separation work.
525
If Evaluation of sub-activity (ADV_TDS.3) or higher is available, the
evaluator ensures that the security architecture description also contains
implementation-dependent information. For example, such a description
might contain information pertaining to coding conventions for parameter
checking that would prevent TSF compromises (e.g. buffer overflows), and
information on stack management for call and return operations. The
evaluator checks the descriptions of the mechanisms to ensure that the level
of detail is such that there is little ambiguity between the description in the
security architecture description and the implementation representation.
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526
This work unit fails if the security architecture description mentions any
module, subsystem, or interface that is not described in the functional
specification or TOE design document.
ADV_ARC.1.2C
The security architecture description shall describe the security domains
maintained by the TSF consistently with the SFRs.
ADV_ARC.1-2
The evaluator shall examine the security architecture description to
determine that it describes the security domains maintained by the TSF.
527
Security domains refer to environments supplied by the TSF for use by
potentially-harmful entities; for example, a typical secure operating system
supplies a set of resources (address space, per-process environment
variables) for use by processes with limited access rights and security
properties. The evaluator determines that the developer's description of the
security domains takes into account all of the SFRs claimed by the TOE.
528
For some TOEs such domains do not exist because all of the interactions
available to users are severely constrained by the TSF. A packet-filter
firewall is an example of such a TOE. Users on the LAN or WAN do not
interact with the TOE, so there need be no security domains; there are only
data structures maintained by the TSF to keep the users' packets separated.
The evaluator ensures that any claim that there are no domains is supported
by the evidence and that no such domains are, in fact, available.
ADV_ARC.1.3C
The security architecture description shall describe how the TSF
initialisation process is secure.
ADV_ARC.1-3
The evaluator shall examine the security architecture description to
determine that the initialisation process preserves security.
529
The information provided in the security architecture description relating to
TSF initialisation is directed at the TOE components that are involved in
bringing the TSF into an initial secure state (i.e. when all parts of the TSF are
operational) when power-on or a reset is applied. This discussion in the
security architecture description should list the system initialisation
components and the processing that occurs in transitioning from the “down”
state to the initial secure state.
530
It is often the case that the components that perform this initialisation
function are not accessible after the secure state is achieved; if this is the case
then the architectural design identifies the components and explains how
they are not reachable by untrusted entities after the TSF has been
established. In this respect, the property that needs to be preserved is that
these components either 1) cannot be accessed by untrusted entities after the
secure state is achieved, or 2) if they provide interfaces to untrusted entities,
these TSFI cannot be used to tamper with the TSF.
531
The TOE components related to TSF initialisation, then, are treated
themselves as part of the TSF, and analysed from that perspective. It should
be noted that even though these are treated as part of the TSF, it is likely that
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a justification (as allowed by TSF internals (ADV_INT)) can be made that
they do not have to meet the internal structuring requirements of ADV_INT.
ADV_ARC.1.4C
The security architecture description shall demonstrate that the TSF
protects itself from tampering.
ADV_ARC.1-4
The evaluator shall examine the security architecture description to
determine that it contains information sufficient to support a determination
that the TSF is able to protect itself from tampering by untrusted active
entities.
532
”Self-protection” refers to the ability of the TSF to protect itself from
manipulation from external entities that may result in changes to the TSF.
For TOEs that have dependencies on other IT entities, it is often the case that
the TOE uses services supplied by the other IT entities in order to perform its
functions. In such cases, the TSF alone does not protect itself because it
depends on the other IT entities to provide some of the protection. For the
purposes of the security architecture description, the notion of self-protection
applies only to the services provided by the TSF through its TSFI, and not to
services provided by underlying IT entities that it uses.
533
Self-protection is typically achieved by a variety of means, ranging from
physical and logical restrictions on access to the TOE; to hardware-based
means (e.g. “execution rings” and memory management functionality); to
software-based means (e.g. boundary checking of inputs on a trusted server).
The evaluator determines that all such mechanisms are described.
534
The evaluator determines that the design description covers how user input is
handled by the TSF in such a way that the TSF does not subject itself to
being corrupted by that user input. For example, the TSF might implement
the notion of privilege and protect itself by using privileged-mode routines to
handle user data. The TSF might make use of processor-based separation
mechanisms such as privilege levels or rings. The TSF might implement
software protection constructs or coding conventions that contribute to
implementing separation of software domains, perhaps by delineating user
address space from system address space. And the TSF might have reliance
its environment to provide some support to the protection of the TSF.
535
All of the mechanisms contributing to the domain separation functions are
described. The evaluator should use knowledge gained from other evidence
(functional specification, TOE design, TSF internals description, other parts
of the security architecture description, or implementation representation, as
included in the assurance package for the TOE) in determining if any
functionality contributing to self-protection was described that is not present
in the security architecture description.
536
Accuracy of the description of the self-protection mechanisms is the property
that the description faithfully describes what is implemented. The evaluator
should use other evidence (functional specification, TOE design, TSF
Internals documentation, other parts of the security architectural description,
implementation representation, as included in the ST for the TOE) in
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determining whether there are discrepancies in any descriptions of the selfprotection mechanisms. If Implementation representation (ADV_IMP) is
included in the assurance package for the TOE, the evaluator will choose a
sample of the implementation representation; the evaluator should also
ensure that the descriptions are accurate for the sample chosen. If an
evaluator cannot understand how a certain self-protection mechanism works
or could work in the system architecture, it may be the case that the
description is not accurate.
ADV_ARC.1.5C
The security architecture description shall demonstrate that the TSF
prevents bypass of the SFR-enforcing functionality.
ADV_ARC.1-5
The evaluator shall examine the security architecture description to
determine that it presents an analysis that adequately describes how the SFRenforcing mechanisms cannot be bypassed.
537
Non-bypassability is a property that the security functionality of the TSF (as
specified by the SFRs) is always invoked. For example, if access control to
files is specified as a capability of the TSF via an SFR, there must be no
interfaces through which files can be accessed without invoking the TSF's
access control mechanism (such as an interface through which a raw disk
access takes place).
538
Describing how the TSF mechanisms cannot be bypassed generally requires
a systematic argument based on the TSF and the TSFIs. The description of
how the TSF works (contained in the design decomposition evidence, such
as the functional specification, TOE design documentation) - along with the
information in the TSS - provides the background necessary for the evaluator
to understand what resources are being protected and what security functions
are being provided. The functional specification provides descriptions of the
TSFIs through which the resources/functions are accessed.
539
The evaluator assesses the description provided (and other information
provided by the developer, such as the functional specification) to ensure that
no available interface can be used to bypass the TSF. This means that every
available interface must be either unrelated to the SFRs that are claimed in
the ST (and does not interact with anything that is used to satisfy SFRs) or
else uses the security functionality that is described in other development
evidence in the manner described. For example, a game would likely be
unrelated to the SFRs, so there must be an explanation of how it cannot
affect security. Access to user data, however, is likely to be related to access
control SFRs, so the explanation would describe how the security
functionality works when invoked through the data-access interfaces. Such a
description in needed for every available interface.
540
An example of a description follows. Suppose the TSF provides file
protection. Further suppose that although the “traditional” system call TSFIs
for open, read, and write invoke the file protection mechanism described in
the TOE design, there exists a TSFI that allows access to a batch job facility
(creating batch jobs, deleting jobs, modifying unprocessed jobs). The
evaluator should be able to determine from the vendor-provided description
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that this TSFI invokes the same protection mechanisms as do the
“traditional” interfaces. This could be done, for example, by referencing the
appropriate sections of the TOE design that discuss how the batch job facility
TSFI achieves its security objectives.
541
Using this same example, suppose there is a TSFI whose sole purpose is to
display the time of day. The evaluator should determine that the description
adequately argues that this TSFI is not capable of manipulating any protected
resources and should not invoke any security functionality.
542
Another example of bypass is when the TSF is supposed to maintain
confidentiality of a cryptographic key (one is allowed to use it for
cryptographic operations, but is not allowed to read/write it). If an attacker
has direct physical access to the device, he might be able to examine sidechannels such as the power usage of the device, the exact timing of the
device, or even any electromagnetic emanations of the device and, from this,
infer the key.
543
If such side-channels may be present, the demonstration should address the
mechanisms that prevent these side-channels from occurring, such as random
internal clocks, dual-line technology etc. Verification of these mechanisms
would be verified by a combination of purely design-based arguments and
testing.
544
For a final example using security functionality rather than a protected
resource, consider an ST that contains FCO_NRO.2 Enforced proof of
origin, which requires that the TSF provides evidence of origination for
information types specified in the ST. Suppose that the “information types”
included all information that is sent by the TOE via e-mail. In this case the
evaluator should examine the description to ensure that all TSFI that can be
invoked to send e-mail perform the “evidence of origination generation”
function are detailed. The description might point to user guidance to show
all places where e-mail can originate (e.g., e-mail program, notification from
scripts/batch jobs) and then how each of these places invokes the evidence
generation function.
545
The evaluator should also ensure that the description is comprehensive, in
that each interface is analysed with respect to the entire set of claimed SFRs.
This may require the evaluator to examine supporting information
(functional specification, TOE design, other parts of the security architectural
description, operational user guidance, and perhaps even the implementation
representation, as provided for the TOE) to determine that the description has
correctly capture all aspects of an interface. The evaluator should consider
what SFRs each TSFI might affect (from the description of the TSFI and its
implementation in the supporting documentation), and then examine the
description to determine whether it covers those aspects.
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11.4
Functional specification (ADV_FSP)
11.4.1
Evaluation of sub-activity (ADV_FSP.1)
11.4.1.1
Objectives
546
The objective of this sub-activity is to determine whether the developer has
provided a high-level description of at least the SFR-enforcing and SFRsupporting TSFI, in terms of descriptions of their parameters. There is no
other required evidence that can be expected to be available to measure the
accuracy of these descriptions; the evaluator merely ensures the descriptions
seem plausible.
11.4.1.2
Input
547
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the operational user guidance;
11.4.1.3
Action ADV_FSP.1.1E
ADV_FSP.1.1C
The functional specification shall describe the purpose and method of use
for each SFR-enforcing and SFR-supporting TSFI.
ADV_FSP.1-1
The evaluator shall examine the functional specification to determine that it
states the purpose of each SFR-supporting and SFR-enforcing TSFI.
548
The purpose of a TSFI is a general statement summarising the functionality
provided by the interface. It is not intended to be a complete statement of the
actions and results related to the interface, but rather a statement to help the
reader understand in general what the interface is intended to be used for.
The evaluator should not only determine that the purpose exists, but also that
it accurately reflects the TSFI by taking into account other information about
the interface, such as the description of the parameters; this can be done in
association with other work units for this component.
549
If an action available through an interface can be traced to one of the SFRs
levied on the TSF), then that interface is SFR-enforcing. Such policies are
not limited to the access control policies, but also refer to any functionality
specified by one of the SFRs contained in the ST. Note that it is possible that
an interface may have various actions and results, some of which may be
SFR-enforcing and some of which may not.
550
Interfaces to (or actions available through an interface relating to) actions
that SFR-enforcing functionality depends on, but need only to function
correctly in order for the security policies of the TOE to be preserved, are
termed SFR supporting. Interfaces to actions on which SFR-enforcing
functionality has no dependence are termed SFR non-interfering.
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551
It should be noted that in order for an interface to be SFR supporting or SFR
non-interfering it must have no SFR-enforcing actions or results. In contrast,
an SFR-enforcing interface may have SFR-supporting actions (for example,
the ability to set the system clock may be an SFR-enforcing action of an
interface, but if that same interface is used to display the system date that
action may only be SFR supporting). An example of a purely SFRsupporting interface is a system call interface that is used both by untrusted
users and by a portion of the TSF that is running in user mode.
552
At this level, it is unlikely that a developer will have expended effort to label
interfaces as SFR-enforcing and SFR-supporting. In the case that this has
been done, the evaluator should verify to the extent that supporting
documentation (e.g., operational user guidance) allows that this identification
is correct. Note that this identification activity is necessary for several work
units for this component.
553
In the more likely case that the developer has not labelled the interfaces, the
evaluator must perform their own identification of the interfaces first, and
then determine whether the required information (for this work unit, the
purpose) is present. Again, because of the lack of supporting evidence this
identification will be difficult and have low assurance that all appropriate
interfaces have been correctly identified, but nonetheless the evaluator
examines other evidence available for the TOE to ensure as complete
coverage as is possible.
ADV_FSP.1.2C
The functional specification shall identify all parameters associated with
each SFR-enforcing and SFR-supporting TSFI.
ADV_FSP.1-2
The evaluator shall examine the functional specification to determine that
the method of use for each SFR-supporting and SFR-enforcing TSFI is
given.
554
See work unit ADV_FSP.1-1 for a discussion on the identification of SFRsupporting and SFR-enforcing TSFI.
555
The method of use for a TSFI summarises how the interface is manipulated
in order to invoke the actions and obtain the results associated with the TSFI.
The evaluator should be able to determine, from reading this material in the
functional specification, how to use each interface. This does not necessarily
mean that there needs to be a separate method of use for each TSFI, as it may
be possible to describe in general how kernel calls are invoked, for instance,
and then identify each interface using that general style. Different types of
interfaces will require different method of use specifications. APIs, network
protocol interfaces, system configuration parameters, and hardware bus
interfaces all have very different methods of use, and this should be taken
into account by the developer when developing the functional specification,
as well as by the evaluator evaluating the functional specification.
556
For administrative interfaces whose functionality is documented as being
inaccessible to untrusted users, the evaluator ensures that the method of
making the functions inaccessible is described in the functional specification.
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It should be noted that this inaccessibility should be tested by the developer
in their test suite.
ADV_FSP.1-3
The evaluator shall examine the presentation of the TSFI to determine that it
identifies all parameters associated with each SFR-enforcing and SFRsupporting TSFI.
557
See work unit ADV_FSP.1-1 for a discussion on the identification of SFRsupporting and SFR-enforcing TSFI.
558
The evaluator examines the functional specification to ensure that all of the
parameters are described for identified TSFI. Parameters are explicit inputs
or outputs to an interface that control the behaviour of that interface. For
examples, parameters are the arguments supplied to an API; the various
fields in packet for a given network protocol; the individual key values in the
Windows Registry; the signals across a set of pins on a chip; etc.
559
While difficult to obtain much assurance that all parameters for the
applicable TSFI have been identified, the evaluator should also check other
evidence provided for the evaluation (e.g., operational user guidance) to see
if behaviour or additional parameters are described there but not in the
functional specification.
ADV_FSP.1.3C
The functional specification shall provide rationale for the implicit
categorisation of interfaces as SFR-non-interfering.
ADV_FSP.1-4
The evaluator shall examine the rationale provided by the developer for the
implicit categorisation of interfaces as SFR-non-interfering to determine that
it is accurate.
560
In the case where the developer has provided adequate documentation to
perform the analysis called for by the rest of the work units for this
component without explicitly identifying SFR-enforcing and SFR-supporting
interfaces, this work unit should be considered satisfied.
561
This work unit is intended to apply to cases where the developer has not
described a portion of the TSFI, claiming that it is SFR-non-interfering and
therefore not subject to other requirements of this component. In such a case,
the developer provides a rationale for this characterisation in sufficient detail
such that the evaluator understands the rationale, the characteristics of the
interfaces affected (e.g., their high-level function with respect to the TOE,
such as “colour palette manipulation”), and that the claim that these are SFRnon-interfering is supported. Given the level of assurance the evaluator
should not expect more detail than is provided for the non-SFR-noninterfering interfaces, and in fact the detail should be much less. In most
cases, individual interfaces should not need to be addressed in the developerprovided rationale section.
ADV_FSP.1.4C
The tracing shall demonstrate that the SFRs trace to TSFIs in the
functional specification.
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ADV_FSP.1-5
The evaluator shall check that the tracing links the SFRs to the
corresponding TSFIs.
562
The tracing is provided by the developer to serve as a guide to which SFRs
are related to which TSFIs. This tracing can be as simple as a table; it is used
as input to the evaluator for use in the following work units, in which the
evaluator verifies its completeness and accuracy.
11.4.1.4
Action ADV_FSP.1.2E
ADV_FSP.1-6
The evaluator shall examine the functional specification to determine that it
is a complete instantiation of the SFRs.
563
To ensure that all SFRs are covered by the functional specification, as well
as the test coverage analysis, the evaluator may build upon the developer's
tracing (see ADV_FSP.1-5 a map between the TOE security functional
requirements and the TSFI. Note that this map may have to be at a level of
detail below the component or even element level of the requirements,
because of operations (assignments, refinements, selections) performed on
the functional requirement by the ST author.
564
For example, the FDP_ACC.1 component contains an element with
assignments. If the ST contained, for instance, ten rules in the FDP_ACC.1
assignment, and these ten rules were covered by three different TSFI, it
would be inadequate for the evaluator to map FDP_ACC.1 to TSFI A, B, and
C and claim they had completed the work unit. Instead, the evaluator would
map FDP_ACC.1 (rule 1) to TSFI A; FDP_ACC.1 (rule 2) to TSFI B; etc. It
might also be the case that the interface is a wrapper interface (e.g., IOCTL),
in which case the mapping would need to be specific to certain set of
parameters for a given interface.
565
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that
they completely map those requirements to the TSFI. The analysis for those
requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST. It is also important to note that since
the parameters, actions, and error messages associated with TSFIs must be
fully specified, the evaluator should be able to determine if all aspects of an
SFR appear to be implemented at the interface level.
ADV_FSP.1-7
The evaluator shall examine the functional specification to determine that it
is an accurate instantiation of the SFRs.
566
For each functional requirement in the ST that results in effects visible at the
TSF boundary, the information in the associated TSFI for that requirement
specifies the required functionality described by the requirement. For
example, if the ST contains a requirement for access control lists, and the
only TSFI that map to that requirement specify functionality for Unix-style
protection bits, then the functionality specification is not accurate with
respect to the requirements.
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567
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that the
evaluator completely map those requirements to the TSFI. The analysis for
those requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST.
11.4.2
Evaluation of sub-activity (ADV_FSP.2)
11.4.2.1
Objectives
568
The objective of this sub-activity is to determine whether the developer has
provided a description of the TSFIs in terms of their purpose, method of use,
and parameters. In addition, the SFR-enforcing actions, results and error
messages of each TSFI that is SFR-enforcing are also described.
11.4.2.2
Input
569
The evaluation evidence for this sub-activity that is required by the workunits is:
570
a)
the ST;
b)
the functional specification;
c)
the TOE design.
The evaluation evidence for this sub-activity that is used if included in the
ST for the TOE is:
a)
the security architecture description;
b)
the operational user guidance;
11.4.2.3
Action ADV_FSP.2.1E
ADV_FSP.2.1C
The functional specification shall completely represent the TSF.
ADV_FSP.2-1
The evaluator shall examine the functional specification to determine that
the TSF is fully represented.
571
The identification of the TSFI is a necessary prerequisite to all other
activities in this sub-activity. The TSF must be identified (done as part of the
TOE design (ADV_TDS) work units) in order to identify the TSFI. This
activity can be done at a high level to ensure that no large groups of
interfaces have been missed (network protocols, hardware interfaces,
configuration files), or at a low level as the evaluation of the functional
specification proceeds.
572
In making an assessment for this work unit, the evaluator determines that all
portions of the TSF are addressed in terms of the interfaces listed in the
functional specification. All portions of the TSF should have a corresponding
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interface description, or if there are no corresponding interfaces for a portion
of the TSF, the evaluator determines that that is acceptable.
ADV_FSP.2.2C
The functional specification shall describe the purpose and method of use
for all TSFI.
ADV_FSP.2-2
The evaluator shall examine the functional specification to determine that it
states the purpose of each TSFI.
573
The purpose of a TSFI is a general statement summarising the functionality
provided by the interface. It is not intended to be a complete statement of the
actions and results related to the interface, but rather a statement to help the
reader understand in general what the interface is intended to be used for.
The evaluator should not only determine that the purpose exists, but also that
it accurately reflects the TSFI by taking into account other information about
the interface, such as the description of actions and error messages.
ADV_FSP.2-3
The evaluator shall examine the functional specification to determine that
the method of use for each TSFI is given.
574
The method of use for a TSFI summarises how the interface is manipulated
in order to invoke the actions and obtain the results associated with the TSFI.
The evaluator should be able to determine, from reading this material in the
functional specification, how to use each interface. This does not necessarily
mean that there needs to be a separate method of use for each TSFI, as it may
be possible to describe in general how kernel calls are invoked, for instance,
and then identify each interface using that general style. Different types of
interfaces will require different method of use specifications. APIs, network
protocol interfaces, system configuration parameters, and hardware bus
interfaces all have very different methods of use, and this should be taken
into account by the developer when developing the functional specification,
as well as by the evaluator evaluating the functional specification.
575
For administrative interfaces whose functionality is documented as being
inaccessible to untrusted users, the evaluator ensures that the method of
making the functions inaccessible is described in the functional specification.
It should be noted that this inaccessibility should be tested by the developer
in their test suite.
576
The evaluator should not only determine that the set of method of use
descriptions exist, but also that they accurately cover each TSFI.
ADV_FSP.2.3C
The functional specification shall identify and describe all parameters
associated with each TSFI.
ADV_FSP.2-4
The evaluator shall examine the presentation of the TSFI to determine that it
completely identifies all parameters associated with every TSFI.
577
The evaluator examines the functional specification to ensure that all of the
parameters are described for each TSFI. Parameters are explicit inputs or
outputs to an interface that control the behaviour of that interface. For
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examples, parameters are the arguments supplied to an API; the various
fields in packet for a given network protocol; the individual key values in the
Windows Registry; the signals across a set of pins on a chip; etc.
578
In order to determine that all of the parameters are present in the TSFI, the
evaluator should examine the rest of the interface description (actions, error
messages, etc.) to determine if the effects of the parameter are accounted for
in the description. The evaluator should also check other evidence provided
for the evaluation (e.g., TOE design, security architecture description,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.2-5
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all parameters associated with every
TSFI.
579
Once all of the parameters have been identified, the evaluator needs to ensure
that they are accurately described, and that the description of the parameters
is complete. A parameter description tells what the parameter is in some
meaningful way. For instance, the interface foo(i) could be described as
having “parameter i which is an integer"; this is not an acceptable parameter
description. A description such as “parameter i is an integer that indicates the
number of users currently logged in to the system” is much more acceptable.
580
In order to determine that the description of the parameters is complete, the
evaluator should examine the rest of the interface description (purpose,
method of use, actions, error messages, etc.) to determine if the descriptions
of the parameter(s) are accounted for in the description. The evaluator should
also check other evidence provided (e.g., TOE design, architectural design,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.2.4C
For SFR-enforcing TSFIs, the functional specification shall describe the
SFR-enforcing actions associated with the TSFI.
ADV_FSP.2-6
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes the SFR-enforcing actions associated
with the SFR-enforcing TSFIs.
581
If an action available through an interface plays a role in enforcing any
security policy on the TOE (that is, if one of the actions of the interface can
be traced to one of the SFRs levied on the TSF), then that interface is SFRenforcing. Such policies are not limited to the access control policies, but
also refer to any functionality specified by one of the SFRs contained in the
ST. Note that it is possible that an interface may have various actions and
results, some of which may be SFR-enforcing and some of which may not.
582
The developer is not required to “label” interfaces as SFR-enforcing, and
likewise is not required to identify actions available through an interface as
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SFR-enforcing. It is the evaluator's responsibility to examine the evidence
provided by the developer and determine that the required information is
present. In the case where the developer has identified the SFR-enforcing
TSFI and SFR-enforcing actions available through those TSFI, the evaluator
must judge completeness and accuracy based on other information supplied
for the evaluation (e.g., TOE design, security architecture description,
operational user guidance), and on the other information presented for the
interfaces (parameters and parameter descriptions, error messages, etc.).
583
In this case (where the developer has provided only the SFR-enforcing
information for SFR-enforcing TSFI) the evaluator also ensures that no
interfaces have been mis-categorised. This is done by examining other
information supplied for the evaluation (e.g., TOE design, security
architecture description, operational user guidance), and the other
information presented for the interfaces (parameters and parameter
descriptions, for example) not labelled as SFR-enforcing.
584
In the case where the developer has provided the same level of information
on all interfaces, the evaluator performs the same type of analysis mentioned
in the previous paragraphs. The evaluator should determine which interfaces
are SFR-enforcing and which are not, and subsequently ensure that the SFRenforcing aspects of the SFR-enforcing actions are appropriately described.
585
The SFR-enforcing actions are those that are visible at any external interface
and that provide for the enforcement of the SFRs being claimed. For
example, if audit requirements are included in the ST, then audit-related
actions would be SFR-enforcing and therefore must be described, even if the
result of that action is generally not visible through the invoked interface (as
is often the case with audit, where a user action at one interface would
produce an audit record visible at another interface).
586
The level of description that is required is that sufficient for the reader to
understand what role the TSFI actions play with respect to the SFR. The
evaluator should keep in mind that the description should be detailed enough
to support the generation (and assessment) of test cases against that interface.
If the description is unclear or lacking detail such that meaningful testing
cannot be conducted against the TSFI, it is likely that the description is
inadequate.
ADV_FSP.2.5C
For SFR-enforcing TSFIs, the functional specification shall describe
direct error messages resulting from processing associated with the SFRenforcing actions.
ADV_FSP.2-7
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes error messages that may result from
SFR-enforcing actions associated with each SFR-enforcing TSFI.
587
This work unit should be performed in conjunction with, or after, work unit
ADV_FSP.2-6 in order to ensure the set of SFR-enforcing TSFI and SFRenforcing actions is correctly identified. The developer may provide more
information than is required (for example, all error messages associated with
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each interface), in which the case the evaluator should restrict their
assessment of completeness and accuracy to only those that they determine
to be associated with SFR-enforcing actions of SFR-enforcing TSFI.
588
Errors can take many forms, depending on the interface being described. For
an API, the interface itself may return an error code, set a global error
condition, or set a certain parameter with an error code. For a configuration
file, an incorrectly configured parameter may cause an error message to be
written to a log file. For a hardware PCI card, an error condition may raise a
signal on the bus, or trigger an exception condition to the CPU.
589
Errors (and the associated error messages) come about through the
invocation of an interface. The processing that occurs in response to the
interface invocation may encounter error conditions, which trigger (through
an implementation-specific mechanism) an error message to be generated. In
some instances this may be a return value from the interface itself; in other
instances a global value may be set and checked after the invocation of an
interface. It is likely that a TOE will have a number of low-level error
messages that may result from fundamental resource conditions, such as
“disk full” or “resource locked”. While these error messages may map to a
large number of TSFI, they could be used to detect instances where detail
from an interface description has been omitted. For instance, a TSFI that
produces a “disk full” message, but has no obvious description of why that
TSFI should cause an access to the disk in its description of actions, might
cause the evaluator to examine other evidence (Security Architecture
(ADV_ARC), TOE design (ADV_TDS)) related that TSFI to determine if
the description is accurate.
590
In order to determine that the description of the error messages of a TSFI is
accurate and complete, the evaluator measures the interface description
against the other evidence provided for the evaluation (e.g., TOE design,
security architecture description, operational user guidance), as well as other
evidence available for that TSFI (parameters, analysis from work unit
ADV_FSP.2-6).
ADV_FSP.2.6C
The tracing shall demonstrate that the SFRs trace to TSFIs in the
functional specification.
ADV_FSP.2-8
The evaluator shall check that the tracing links the SFRs to the
corresponding TSFIs.
591
The tracing is provided by the developer to serve as a guide to which SFRs
are related to which TSFIs. This tracing can be as simple as a table; it is used
as input to the evaluator for use in the following work units, in which the
evaluator verifies its completeness and accuracy.
11.4.2.4
Action ADV_FSP.2.2E
ADV_FSP.2-9
The evaluator shall examine the functional specification to determine that it
is a complete instantiation of the SFRs.
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592
To ensure that all SFRs are covered by the functional specification, as well
as the test coverage analysis, the evaluator may build upon the developer's
tracing (see ADV_FSP.2-8 a map between the TOE security functional
requirements and the TSFI. Note that this map may have to be at a level of
detail below the component or even element level of the requirements,
because of operations (assignments, refinements, selections) performed on
the functional requirement by the ST author.
593
For example, the FDP_ACC.1 component contains an element with
assignments. If the ST contained, for instance, ten rules in the FDP_ACC.1
assignment, and these ten rules were covered by three different TSFI, it
would be inadequate for the evaluator to map FDP_ACC.1 to TSFI A, B, and
C and claim they had completed the work unit. Instead, the evaluator would
map FDP_ACC.1 (rule 1) to TSFI A; FDP_ACC.1 (rule 2) to TSFI B; etc. It
might also be the case that the interface is a wrapper interface (e.g., IOCTL),
in which case the mapping would need to be specific to certain set of
parameters for a given interface.
594
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that
they completely map those requirements to the TSFI. The analysis for those
requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST. It is also important to note that since
the parameters, actions, and error messages associated with TSFIs must be
fully specified, the evaluator should be able to determine if all aspects of an
SFR appear to be implemented at the interface level.
ADV_FSP.2-10
The evaluator shall examine the functional specification to determine that it
is an accurate instantiation of the SFRs.
595
For each functional requirement in the ST that results in effects visible at the
TSF boundary, the information in the associated TSFI for that requirement
specifies the required functionality described by the requirement. For
example, if the ST contains a requirement for access control lists, and the
only TSFI that map to that requirement specify functionality for Unix-style
protection bits, then the functionality specification is not accurate with
respect to the requirements.
596
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that the
evaluator completely map those requirements to the TSFI. The analysis for
those requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST.
11.4.3
Evaluation of sub-activity (ADV_FSP.3)
11.4.3.1
Objectives
597
The objective of this sub-activity is to determine whether the developer has
provided a description of the TSFIs in terms of their purpose, method of use,
and parameters. In addition, the actions, results and error messages of each
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TSFI are also described sufficiently that it can be determined whether they
are SFR-enforcing, with the SFR-enforcing TSFI being described in more
detail than other TSFIs.
11.4.3.2
Input
598
The evaluation evidence for this sub-activity that is required by the workunits is:
599
a)
the ST;
b)
the functional specification;
c)
the TOE design.
The evaluation evidence for this sub-activity that is used if included in the
ST for the TOE is:
a)
the security architecture description;
b)
the implementation representation;
c)
the TSF internals description;
d)
the operational user guidance;
11.4.3.3
Action ADV_FSP.3.1E
ADV_FSP.3.1C
The functional specification shall completely represent the TSF.
ADV_FSP.3-1
The evaluator shall examine the functional specification to determine that
the TSF is fully represented.
600
The identification of the TSFI is a necessary prerequisite to all other
activities in this sub-activity. The TSF must be identified (done as part of the
TOE design (ADV_TDS) work units) in order to identify the TSFI. This
activity can be done at a high level to ensure that no large groups of
interfaces have been missed (network protocols, hardware interfaces,
configuration files), or at a low level as the evaluation of the functional
specification proceeds.
601
In making an assessment for this work unit, the evaluator determines that all
portions of the TSF are addressed in terms of the interfaces listed in the
functional specification. All portions of the TSF should have a corresponding
interface description, or if there are no corresponding interfaces for a portion
of the TSF, the evaluator determines that that is acceptable.
ADV_FSP.3.2C
The functional specification shall describe the purpose and method of use
for all TSFI.
ADV_FSP.3-2
The evaluator shall examine the functional specification to determine that it
states the purpose of each TSFI.
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602
The purpose of a TSFI is a general statement summarising the functionality
provided by the interface. It is not intended to be a complete statement of the
actions and results related to the interface, but rather a statement to help the
reader understand in general what the interface is intended to be used for.
The evaluator should not only determine that the purpose exists, but also that
it accurately reflects the TSFI by taking into account other information about
the interface, such as the description of actions and error messages.
ADV_FSP.3-3
The evaluator shall examine the functional specification to determine that
the method of use for each TSFI is given.
603
The method of use for a TSFI summarises how the interface is manipulated
in order to invoke the actions and obtain the results associated with the TSFI.
The evaluator should be able to determine, from reading this material in the
functional specification, how to use each interface. This does not necessarily
mean that there needs to be a separate method of use for each TSFI, as it may
be possible to describe in general how kernel calls are invoked, for instance,
and then identify each interface using that general style. Different types of
interfaces will require different method of use specifications. APIs, network
protocol interfaces, system configuration parameters, and hardware bus
interfaces all have very different methods of use, and this should be taken
into account by the developer when developing the functional specification,
as well as by the evaluator evaluating the functional specification.
604
For administrative interfaces whose functionality is documented as being
inaccessible to untrusted users, the evaluator ensures that the method of
making the functions inaccessible is described in the functional specification.
It should be noted that this inaccessibility should be tested by the developer
in their test suite.
605
The evaluator should not only determine that the set of method of use
descriptions exist, but also that they accurately cover each TSFI.
ADV_FSP.3.3C
The functional specification shall identify and describe all parameters
associated with each TSFI.
ADV_FSP.3-4
The evaluator shall examine the presentation of the TSFI to determine that it
completely identifies all parameters associated with every TSFI.
606
The evaluator examines the functional specification to ensure that all of the
parameters are described for each TSFI. Parameters are explicit inputs or
outputs to an interface that control the behaviour of that interface. For
examples, parameters are the arguments supplied to an API; the various
fields in packet for a given network protocol; the individual key values in the
Windows Registry; the signals across a set of pins on a chip; etc.
607
In order to determine that all of the parameters are present in the TSFI, the
evaluator should examine the rest of the interface description (actions, error
messages, etc.) to determine if the effects of the parameter are accounted for
in the description. The evaluator should also check other evidence provided
for the evaluation (e.g., TOE design, security architecture description,
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operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.3-5
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all parameters associated with every
TSFI.
608
Once all of the parameters have been identified, the evaluator needs to ensure
that they are accurately described, and that the description of the parameters
is complete. A parameter description tells what the parameter is in some
meaningful way. For instance, the interface foo(i) could be described as
having “parameter i which is an integer”; this is not an acceptable parameter
description. A description such as “parameter i is an integer that indicates the
number of users currently logged in to the system” is much more acceptable.
609
In order to determine that the description of the parameters is complete, the
evaluator should examine the rest of the interface description (purpose,
method of use, actions, error messages, etc.) to determine if the descriptions
of the parameter(s) are accounted for in the description. The evaluator should
also check other evidence provided (e.g., TOE design, architectural design,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.3.4C
For SFR-enforcing TSFIs, the functional specification shall describe the
SFR-enforcing actions associated with the TSFI.
ADV_FSP.3-6
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes the SFR-enforcing actions associated
with the SFR-enforcing TSFIs.
610
If an action available through an interface plays a role in enforcing any
security policy on the TOE (that is, if one of the actions of the interface can
be traced to one of the SFRs levied on the TSF), then that interface is SFRenforcing. Such policies are not limited to the access control policies, but
also refer to any functionality specified by one of the SFRs contained in the
ST. Note that it is possible that an interface may have various actions and
results, some of which may be SFR-enforcing and some of which may not.
611
The developer is not required to “label” interfaces as SFR-enforcing, and
likewise is not required to identify actions available through an interface as
SFR-enforcing. It is the evaluator's responsibility to examine the evidence
provided by the developer and determine that the required information is
present. In the case where the developer has identified the SFR-enforcing
TSFI and SFR-enforcing actions available through those TSFI, the evaluator
must judge completeness and accuracy based on other information supplied
for the evaluation (e.g., TOE design, security architecture description,
operational user guidance), and on the other information presented for the
interfaces (parameters and parameter descriptions, error messages, etc.).
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612
In this case (developer has provided only the SFR-enforcing information for
SFR-enforcing TSFI) the evaluator also ensures that no interfaces have been
mis-categorised. This is done by examining other information supplied for
the evaluation (e.g., TOE design, security architecture description,
operational user guidance), and the other information presented for the
interfaces (parameters and parameter descriptions, for example) not labelled
as SFR-enforcing. The analysis done for work units ADV_FSP.3-7 and
ADV_FSP.3-8 are also used in making this determination.
613
In the case where the developer has provided the same level of information
on all interfaces, the evaluator performs the same type of analysis mentioned
in the previous paragraphs. The evaluator should determine which interfaces
are SFR-enforcing and which are not, and subsequently ensure that the SFRenforcing aspects of the SFR-enforcing actions are appropriately described.
Note that in this case, the evaluator should be able to perform the bulk of the
work associated with work unit ADV_FSP.3-8 in the course of performing
this SFR-enforcing analysis.
614
The SFR-enforcing actions are those that are visible at any external interface
and that provide for the enforcement of the SFRs being claimed. For
example, if audit requirements are included in the ST, then audit-related
actions would be SFR-enforcing and therefore must be described, even if the
result of that action is generally not visible through the invoked interface (as
is often the case with audit, where a user action at one interface would
produce an audit record visible at another interface).
615
The level of description that is required is that sufficient for the reader to
understand what role the TSFI actions play with respect to the SFR. The
evaluator should keep in mind that the description should be detailed enough
to support the generation (and assessment) of test cases against that interface.
If the description is unclear or lacking detail such that meaningful testing
cannot be conducted against the TSFI, it is likely that the description is
inadequate.
ADV_FSP.3.5C
For SFR-enforcing TSFIs, the functional specification shall describe
direct error messages resulting from security enforcing effects and
exceptions associated with invocation of the TSFI.
ADV_FSP.3-7
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes error messages that may result from an
invocation of each SFR-enforcing TSFI.
616
This work unit should be performed in conjunction with, or after, work unit
ADV_FSP.3-6 in order to ensure the set of SFR-enforcing TSFI is correctly
identified. The evaluator should note that the requirement and associated
work unit is that all error messages associated with an SFR-enforcing TSFI
must be described, not just those associated with SFR-enforcing actions. This
is because at this level of assurance, the “extra” information provided by the
error message descriptions should be used in determining whether all of the
SFR-enforcing aspects of an interface have been appropriately described. For
instance, if an error message associated with a TSFI (e.g., “access denied”)
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indicated that an SFR-enforcing decision or action had taken place, but in the
description of the SFR-enforcing actions there was no mention of that
particular SFR-enforcing mechanism, then the description may not be
complete.
617
Errors can take many forms, depending on the interface being described. For
an API, the interface itself may return an error code, set a global error
condition, or set a certain parameter with an error code. For a configuration
file, an incorrectly configured parameter may cause an error message to be
written to a log file. For a hardware PCI card, an error condition may raise a
signal on the bus, or trigger an exception condition to the CPU.
618
Errors (and the associated error messages) come about through the
invocation of an interface. The processing that occurs in response to the
interface invocation may encounter error conditions, which trigger (through
an implementation-specific mechanism) an error message to be generated. In
some instances this may be a return value from the interface itself; in other
instances a global value may be set and checked after the invocation of an
interface. It is likely that a TOE will have a number of low-level error
messages that may result from fundamental resource conditions, such as
“disk full” or “resource locked”. While these error messages may map to a
large number of TSFI, they could be used to detect instances where detail
from an interface description has been omitted. For instance, a TSFI that
produces a “disk full” message, but has no obvious description of why that
TSFI should cause an access to the disk in its description of actions, might
cause the evaluator to examine other evidence (Security Architecture
(ADV_ARC), TOE design (ADV_TDS)) related that TSFI to determine if
the description is accurate.
619
In order to determine that the description of the error messages of a TSFI is
accurate and complete, the evaluator measures the interface description
against the other evidence provided for the evaluation (e.g., TOE design,
security architecture description, operational user guidance), as well as for
other evidence supplied for that TSFI (description of SFR-enforcing actions,
summary of non-SFR-enforcing actions and results).
ADV_FSP.3.6C
The functional specification shall summarise the non-SFR-enforcing
actions associated with each TSFI.
ADV_FSP.3-8
The evaluator shall examine the presentation of the TSFI to determine that it
summarises the non-SFR-enforcing actions associated with each TSFI.
620
The purpose of this work unit is to supplement the details about the SFRenforcing actions (provided in work unit ADV_FSP.3-6) with a summary of
the remaining actions (i.e., those that are not SFR-enforcing). This covers all
non-SFR-enforcing actions, whether invokable through SFR-enforcing TSFI
or through non-SFR-enforcing TSFI. Such a summary about all non-SFRenforcing actions helps to provide a more complete picture of the functions
provided by the TSF, and is to be used by the evaluator in determining
whether an action or TSFI may have been mis-categorised.
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621
The information to be provided is more abstract than that required for SFRenforcing actions. While it should still be detailed enough so that the reader
can understand what the action does, the description does not have to be
detailed enough to support writing tests against it, for instance. For the
evaluator, the key is that the information must be sufficient to make a
positive determination that the action is non-SFR-enforcing. If that level of
information is missing, the summary is insufficient and more information
must be obtained.
ADV_FSP.3.7C
The tracing shall demonstrate that the SFRs trace to TSFIs in the
functional specification.
ADV_FSP.3-9
The evaluator shall check that the tracing links the SFRs to the
corresponding TSFIs.
622
The tracing is provided by the developer to serve as a guide to which SFRs
are related to which TSFIs. This tracing can be as simple as a table; it is used
as input to the evaluator for use in the following work units, in which the
evaluator verifies its completeness and accuracy.
11.4.3.4
Action ADV_FSP.3.2E
ADV_FSP.3-10
The evaluator shall examine the functional specification to determine that it
is a complete instantiation of the SFRs.
623
To ensure that all SFRs are covered by the functional specification, as well
as the test coverage analysis, the evaluator may build upon the developer's
tracing (see ADV_FSP.3-9 a map between the TOE security functional
requirements and the TSFI. Note that this map may have to be at a level of
detail below the component or even element level of the requirements,
because of operations (assignments, refinements, selections) performed on
the functional requirement by the ST author.
624
For example, the FDP_ACC.1 component contains an element with
assignments. If the ST contained, for instance, ten rules in the FDP_ACC.1
assignment, and these ten rules were covered by three different TSFI, it
would be inadequate for the evaluator to map FDP_ACC.1 to TSFI A, B, and
C and claim they had completed the work unit. Instead, the evaluator would
map FDP_ACC.1 (rule 1) to TSFI A; FDP_ACC.1 (rule 2) to TSFI B; etc. It
might also be the case that the interface is a wrapper interface (e.g., IOCTL),
in which case the mapping would need to be specific to certain set of
parameters for a given interface.
625
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that
they completely map those requirements to the TSFI. The analysis for those
requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST. It is also important to note that since
the parameters, actions, and error messages associated with TSFIs must be
fully specified, the evaluator should be able to determine if all aspects of an
SFR appear to be implemented at the interface level.
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ADV_FSP.3-11
The evaluator shall examine the functional specification to determine that it
is an accurate instantiation of the SFRs.
626
For each functional requirement in the ST that results in effects visible at the
TSF boundary, the information in the associated TSFI for that requirement
specifies the required functionality described by the requirement. For
example, if the ST contains a requirement for access control lists, and the
only TSFI that map to that requirement specify functionality for Unix-style
protection bits, then the functionality specification is not accurate with
respect to the requirements.
627
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that the
evaluator completely map those requirements to the TSFI. The analysis for
those requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST.
11.4.4
Evaluation of sub-activity (ADV_FSP.4)
11.4.4.1
Objectives
628
The objective of this sub-activity is to determine whether the developer has
completely described all of the TSFI in a manner such that the evaluator is
able to determine whether the TSFI are completely and accurately described,
and appears to implement the security functional requirements of the ST.
11.4.4.2
Input
629
The evaluation evidence for this sub-activity that is required by the workunits is:
630
a)
the ST;
b)
the functional specification;
c)
the TOE design.
The evaluation evidence for this sub-activity that is used if included in the
ST for the TOE is:
a)
the security architecture description;
b)
the implementation representation;
c)
the TSF internals description;
d)
the operational user guidance;
11.4.4.3
Application notes
631
The functional specification describes the interfaces to the TSF (the TSFI) in
a structured manner. Because of the dependency on Evaluation of sub-
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activity (ADV_TDS.1), the evaluator is expected to have identified the TSF
prior to beginning work on this sub-activity. Without firm knowledge of
what comprises the TSF, it is not possible to assess the completeness of the
TSFI.
632
In performing the various work units included in this family, the evaluator is
asked to make assessments of accuracy and completeness of several factors
(the TSFI itself, as well as the individual components (parameters, actions,
error messages, etc.) of the TSFI). In doing this analysis, the evaluator is
expected to use the documentation provided for the evaluation. This includes
the ST, the TOE design, and may include other documentation such as the
user and administrative guidance, security architecture description, and
implementation representation. The documentation should be examined in an
iterative fashion. The evaluator may read, for example, in the TOE design
how a certain function is implemented, but see no way to invoke that
function from the interface. This might cause the evaluator to question the
completeness of a particular TSFI description, or whether an interface has
been left out of the functional specification altogether. Describing analysis
activities of this sort in the ETR is a key method in providing rationale that
the work units have been performed appropriately.
633
It should be recognised that there exist functional requirements whose
functionality is manifested wholly or in part architecturally, rather than
through a specific mechanism. An example of this is the implementation of
mechanisms implementing the Residual information protection (FDP_RIP)
requirements. Such mechanisms typically are implemented to ensure a
behaviour isn't present, which is difficult to test and typically is verified
through analysis. In the cases where such functional requirements are
included in the ST, it is expected that the evaluator recognise that there may
be SFRs of this type that have no interfaces, and that this should not be
considered a deficiency in the functional specification.
11.4.4.4
Action ADV_FSP.4.1E
ADV_FSP.4.1C
The functional specification shall completely represent the TSF.
ADV_FSP.4-1
The evaluator shall examine the functional specification to determine that
the TSF is fully represented.
634
The identification of the TSFI is a necessary prerequisite to all other
activities in this sub-activity. The TSF must be identified (done as part of the
TOE design (ADV_TDS) work units) in order to identify the TSFI. This
activity can be done at a high level to ensure that no large groups of
interfaces have been missed (network protocols, hardware interfaces,
configuration files), or at a low level as the evaluation of the functional
specification proceeds.
635
In making an assessment for this work unit, the evaluator determines that all
portions of the TSF are addressed in terms of the interfaces listed in the
functional specification. All portions of the TSF should have a corresponding
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interface description, or if there are no corresponding interfaces for a portion
of the TSF, the evaluator determines that that is acceptable.
ADV_FSP.4.2C
The functional specification shall describe the purpose and method of use
for all TSFI.
ADV_FSP.4-2
The evaluator shall examine the functional specification to determine that it
states the purpose of each TSFI.
636
The purpose of a TSFI is a general statement summarising the functionality
provided by the interface. It is not intended to be a complete statement of the
actions and results related to the interface, but rather a statement to help the
reader understand in general what the interface is intended to be used for.
The evaluator should not only determine that the purpose exists, but also that
it accurately reflects the TSFI by taking into account other information about
the interface, such as the description of actions and error messages.
ADV_FSP.4-3
The evaluator shall examine the functional specification to determine that
the method of use for each TSFI is given.
637
The method of use for a TSFI summarises how the interface is manipulated
in order to invoke the actions and obtain the results associated with the TSFI.
The evaluator should be able to determine, from reading this material in the
functional specification, how to use each interface. This does not necessarily
mean that there needs to be a separate method of use for each TSFI, as it may
be possible to describe in general how kernel calls are invoked, for instance,
and then identify each interface using that general style. Different types of
interfaces will require different method of use specifications. APIs, network
protocol interfaces, system configuration parameters, and hardware bus
interfaces all have very different methods of use, and this should be taken
into account by the developer when developing the functional specification,
as well as by the evaluator evaluating the functional specification.
638
For administrative interfaces whose functionality is documented as being
inaccessible to untrusted users, the evaluator ensures that the method of
making the functions inaccessible is described in the functional specification.
It should be noted that this inaccessibility should be tested by the developer
in their test suite.
639
The evaluator should not only determine that the set of method of use
descriptions exist, but also that they accurately cover each TSFI.
ADV_FSP.4.3C
The functional specification shall identify and describe all parameters
associated with each TSFI.
ADV_FSP.4-4
The evaluator shall examine the presentation of the TSFI to determine that it
completely identifies all parameters associated with every TSFI.
640
The evaluator examines the functional specification to ensure that all of the
parameters are described for each TSFI. Parameters are explicit inputs or
outputs to an interface that control the behaviour of that interface. For
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examples, parameters are the arguments supplied to an API; the various
fields in packet for a given network protocol; the individual key values in the
Windows Registry; the signals across a set of pins on a chip; etc.
641
In order to determine that all of the parameters are present in the TSFI, the
evaluator should examine the rest of the interface description (actions, error
messages, etc.) to determine if the effects of the parameter are accounted for
in the description. The evaluator should also check other evidence provided
for the evaluation (e.g., TOE design, security architecture description,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.4-5
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all parameters associated with every
TSFI.
642
Once all of the parameters have been identified, the evaluator needs to ensure
that they are accurately described, and that the description of the parameters
is complete. A parameter description tells what the parameter is in some
meaningful way. For instance, the interface foo(i) could be described as
having “parameter i which is an integer”; this is not an acceptable parameter
description. A description such as “parameter i is an integer that indicates the
number of users currently logged in to the system” is much more acceptable.
643
In order to determine that the description of the parameters is complete, the
evaluator should examine the rest of the interface description (purpose,
method of use, actions, error messages, etc.) to determine if the descriptions
of the parameter(s) are accounted for in the description. The evaluator should
also check other evidence provided (e.g., TOE design, architectural design,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.4.4C
The functional specification shall describe all actions associated with each
TSFI.
ADV_FSP.4-6
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all actions associated with every TSFI.
644
The evaluator checks to ensure that all of the actions are described. actions
available through an interface describe what the interface does (as opposed to
the TOE design, which describes how the actions are provided by the TSF).
645
Actions of an interface describe functionality that can be invoked through the
interface, and can be categorised as regular actions, and SFR-related actions.
Regular actions are descriptions of what the interface does. The amount of
information provided for this description is dependant on the complexity of
the interface. The SFR-related actions are those that are visible at any
external interface (for instance, audit activity caused by the invocation of an
interface (assuming audit requirements are included in the ST) should be
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described, even though the result of that action is generally not visible
through the invoked interface). Depending on the parameters of an interface,
there may be many different actions able to be invoked through the interface
(for instance, an API might have the first parameter be a “subcommand”, and
the following parameters be specific to that subcommand. The IOCTL API
in some Unix systems is an example of such an interface).
646
In order to determine that the description of the actions of a TSFI is
complete, the evaluator should review the rest of the interface description
(parameter descriptions, error messages, etc.) to determine if the actions
described are accounted for. The evaluator should also analyse other
evidence provided for the evaluation (e.g., TOE design, security architecture
description, operational user guidance, implementation representation) to see
if there is evidence of actions that are described there but not in the
functional specification.
ADV_FSP.4.5C
The functional specification shall describe all direct error messages that
may result from security enforcing effects and exceptions associated with
an invocation of each TSFI.
ADV_FSP.4-7
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all errors messages resulting from an
invocation of each TSFI.
647
Errors can take many forms, depending on the interface being described. For
an API, the interface itself may return an error code; set a global error
condition, or set a certain parameter with an error code. For a configuration
file, an incorrectly configured parameter may cause an error message to be
written to a log file. For a hardware PCI card, an error condition may raise a
signal on the bus, or trigger an exception condition to the CPU.
648
Errors (and the associated error messages) come about through the
invocation of an interface. The processing that occurs in response to the
interface invocation may encounter error conditions, which trigger (through
an implementation-specific mechanism) an error message to be generated. In
some instances this may be a return value from the interface itself; in other
instances a global value may be set and checked after the invocation of an
interface. It is likely that a TOE will have a number of low-level error
messages that may result from fundamental resource conditions, such as
“disk full” or “resource locked”. While these error messages may map to a
large number of TSFI, they could be used to detect instances where detail
from an interface description has been omitted. For instance, a TSFI that
produces a “disk full” message, but has no obvious description of why that
TSFI should cause an access to the disk in its description of actions, might
cause the evaluator to examine other evidence (Security Architecture
(ADV_ARC), TOE design (ADV_TDS)) related that TSFI to determine if
the description is complete and accurate.
649
The evaluator determines that, for each TSFI, the exact set of error messages
that can be returned on invoking that interface can be determined. The
evaluator reviews the evidence provided for the interface to determine if the
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set of errors seems complete. They cross-check this information with other
evidence provided for the evaluation (e.g., TOE design, security architecture
description, operational user guidance, implementation representation) to
ensure that there are no errors steaming from processing mentioned that are
not included in the functional specification.
ADV_FSP.4-8
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes the meaning of all errors associated with
each TSFI.
650
In order to determine accuracy, the evaluator must be able to understand
meaning of the error. For example, if an interface returns a numeric code of
0, 1, or 2, the evaluator would not be able to understand the error if the
functional specification only listed: “possible errors resulting from
invocation of the foo() interface are 0, 1, or 2”. Instead the evaluator checks
to ensure that the errors are described such as: “possible errors resulting from
invocation of the foo() interface are 0 (processing successful), 1 (file not
found), or 2 (incorrect filename specification)”.
651
In order to determine that the description of the errors due to invoking a
TSFI is complete, the evaluator examines the rest of the interface description
(parameter descriptions, actions, etc.) to determine if potential error
conditions that might be caused by using such an interface are accounted for.
The evaluator also checks other evidence provided for the evaluation (e.g.
TOE design, security architecture description, operational user guidance,
implementation representation) to see if error processing related to the TSFI
is described there but is not described in the functional specification.
ADV_FSP.4.6C
The tracing shall demonstrate that the SFRs trace to TSFIs in the
functional specification.
ADV_FSP.4-9
The evaluator shall check that the tracing links the SFRs to the
corresponding TSFIs.
652
The tracing is provided by the developer to serve as a guide to which SFRs
are related to which TSFIs. This tracing can be as simple as a table; it is used
as input to the evaluator for use in the following work units, in which the
evaluator verifies its completeness and accuracy.
11.4.4.5
Action ADV_FSP.4.2E
ADV_FSP.4-10
The evaluator shall examine the functional specification to determine that it
is a complete instantiation of the SFRs.
653
To ensure that all SFRs are covered by the functional specification, as well
as the test coverage analysis, the evaluator may build upon the developer's
tracing (see ADV_FSP.4-9 a map between the TOE security functional
requirements and the TSFI. Note that this map may have to be at a level of
detail below the component or even element level of the requirements,
because of operations (assignments, refinements, selections) performed on
the functional requirement by the ST author.
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654
For example, the FDP_ACC.1 component contains an element with
assignments. If the ST contained, for instance, ten rules in the FDP_ACC.1
assignment, and these ten rules were covered by three different TSFI, it
would be inadequate for the evaluator to map FDP_ACC.1 to TSFI A, B, and
C and claim they had completed the work unit. Instead, the evaluator would
map FDP_ACC.1 (rule 1) to TSFI A; FDP_ACC.1 (rule 2) to TSFI B; etc. It
might also be the case that the interface is a wrapper interface (e.g., IOCTL),
in which case the mapping would need to be specific to certain set of
parameters for a given interface.
655
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that
they completely map those requirements to the TSFI. The analysis for those
requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST. It is also important to note that since
the parameters, actions, and error messages associated with TSFIs must be
fully specified, the evaluator should be able to determine if all aspects of an
SFR appear to be implemented at the interface level.
ADV_FSP.4-11
The evaluator shall examine the functional specification to determine that it
is an accurate instantiation of the SFRs.
656
For each functional requirement in the ST that results in effects visible at the
TSF boundary, the information in the associated TSFI for that requirement
specifies the required functionality described by the requirement. For
example, if the ST contains a requirement for access control lists, and the
only TSFI that map to that requirement specify functionality for Unix-style
protection bits, then the functionality specification is not accurate with
respect to the requirements.
657
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that the
evaluator completely map those requirements to the TSFI. The analysis for
those requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST.
11.4.5
Evaluation of sub-activity (ADV_FSP.5)
11.4.5.1
Objectives
658
The objective of this sub-activity is to determine whether the developer has
completely described all of the TSFI in a manner such that the evaluator is
able to determine whether the TSFI are completely and accurately described,
and appears to implement the security functional requirements of the ST. The
completeness of the interfaces is judged based upon the implementation
representation.
11.4.5.2
Input
659
The evaluation evidence for this sub-activity that is required by the workunits is:
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660
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the implementation representation.
The evaluation evidence for this sub-activity that is used if included in the
ST for the TOE is:
a)
the security architecture description;
b)
the TSF internals description;
c)
the formal security policy model;
d)
the operational user guidance;
11.4.5.3
Action ADV_FSP.5.1E
ADV_FSP.5.1C
The functional specification shall completely represent the TSF.
ADV_FSP.5-1
The evaluator shall examine the functional specification to determine that
the TSF is fully represented.
661
The identification of the TSFI is a necessary prerequisite to all other
activities in this sub-activity. The TSF must be identified (done as part of the
TOE design (ADV_TDS) work units) in order to identify the TSFI. This
activity can be done at a high level to ensure that no large groups of
interfaces have been missed (network protocols, hardware interfaces,
configuration files), or at a low level as the evaluation of the functional
specification proceeds.
662
In making an assessment for this work unit, the evaluator determines that all
portions of the TSF are addressed in terms of the interfaces listed in the
functional specification. All portions of the TSF should have a corresponding
interface description, or if there are no corresponding interfaces for a portion
of the TSF, the evaluator determines that that is acceptable.
ADV_FSP.5.2C
The functional specification shall describe the TSFI using a semi-formal
style.
ADV_FSP.5-2
The evaluator shall examine the functional specification to determine that it
is presented using a semiformal style.
663
A semi-formal presentation is characterised by a standardised format with a
well-defined syntax that reduces ambiguity that may occur in informal
presentations. Since the intent of the semi-formal format is to enhance the
reader's ability to understand the presentation, use of certain structured
presentation methods (pseudo-code, flow charts, block diagrams) are
appropriate, though not required.
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664
For the purposes of this activity, the evaluator should ensure that the
interface descriptions are formatted in a structured, consistent manner and
use common terminology. A semiformal presentation of the interfaces also
implies that the level of detail of the presentation for the interfaces is largely
consistent across all TSFI. For the functional specification, it is acceptable to
refer to external specifications for portions of the interface as long as those
external specifications are themselves semiformal.
ADV_FSP.5.3C
The functional specification shall describe the purpose and method of use
for all TSFI.
ADV_FSP.5-3
The evaluator shall examine the functional specification to determine that it
states the purpose of each TSFI.
665
The purpose of a TSFI is a general statement summarising the functionality
provided by the interface. It is not intended to be a complete statement of the
actions and results related to the interface, but rather a statement to help the
reader understand in general what the interface is intended to be used for.
The evaluator should not only determine that the purpose exists, but also that
it accurately reflects the TSFI by taking into account other information about
the interface, such as the description of actions and error messages.
ADV_FSP.5-4
The evaluator shall examine the functional specification to determine that
the method of use for each TSFI is given.
666
The method of use for a TSFI summarises how the interface is manipulated
in order to invoke the actions and obtain the results associated with the TSFI.
The evaluator should be able to determine, from reading this material in the
functional specification, how to use each interface. This does not necessarily
mean that there needs to be a separate method of use for each TSFI, as it may
be possible to describe in general how kernel calls are invoked, for instance,
and then identify each interface using that general style. Different types of
interfaces will require different method of use specifications. APIs, network
protocol interfaces, system configuration parameters, and hardware bus
interfaces all have very different methods of use, and this should be taken
into account by the developer when developing the functional specification,
as well as by the evaluator evaluating the functional specification.
667
For administrative interfaces whose functionality is documented as being
inaccessible to untrusted users, the evaluator ensures that the method of
making the functions inaccessible is described in the functional specification.
It should be noted that this inaccessibility should be tested by the developer
in their test suite.
668
The evaluator should not only determine that the set of method of use
descriptions exist, but also that they accurately cover each TSFI.
ADV_FSP.5.4C
The functional specification shall identify and describe all parameters
associated with each TSFI.
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ADV_FSP.5-5
The evaluator shall examine the presentation of the TSFI to determine that it
completely identifies all parameters associated with every TSFI.
669
The evaluator examines the functional specification to ensure that all of the
parameters are described for each TSFI. Parameters are explicit inputs or
outputs to an interface that control the behaviour of that interface. For
examples, parameters are the arguments supplied to an API; the various
fields in packet for a given network protocol; the individual key values in the
Windows Registry; the signals across a set of pins on a chip; etc.
670
In order to determine that all of the parameters are present in the TSFI, the
evaluator should examine the rest of the interface description (actions, error
messages, etc.) to determine if the effects of the parameter are accounted for
in the description. The evaluator should also check other evidence provided
for the evaluation (e.g., TOE design, security architecture description,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.5.5C
The functional specification shall describe all actions associated with each
TSFI.
ADV_FSP.5-6
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all parameters associated with every
TSFI.
671
Once all of the parameters have been identified, the evaluator needs to ensure
that they are accurately described, and that the description of the parameters
is complete. A parameter description tells what the parameter is in some
meaningful way. For instance, the interface foo(i) could be described as
having “parameter i which is an integer”; this is not an acceptable parameter
description. A description such as “parameter i is an integer that indicates the
number of users currently logged in to the system”. is much more acceptable.
672
In order to determine that the description of the parameters is complete, the
evaluator should examine the rest of the interface description (purpose,
method of use, actions, error messages, etc.) to determine if the descriptions
of the parameter(s) are accounted for in the description. The evaluator should
also check other evidence provided (e.g., TOE design, architectural design,
operational user guidance, implementation representation) to see if behaviour
or additional parameters are described there but not in the functional
specification.
ADV_FSP.5-7
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all actions associated with every TSFI.
673
The evaluator checks to ensure that all of the actions are described. actions
available through an interface describe what the interface does (as opposed to
the TOE design, which describes how the actions are provided by the TSF).
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674
actions of an interface describe functionality that can be invoked through the
interface, and can be categorised as regular actions, and SFR-related actions.
Regular actions are descriptions of what the interface does. The amount of
information provided for this description is dependant on the complexity of
the interface. The SFR-related actions are those that are visible at any
external interface (for instance, audit activity caused by the invocation of an
interface (assuming audit requirements are included in the ST) should be
described, even though the result of that action is generally not visible
through the invoked interface). Depending on the parameters of an interface,
there may be many different actions able to be invoked through the interface
(for instance, an API might have the first parameter be a “subcommand”, and
the following parameters be specific to that subcommand. The IOCTL API
in some Unix systems is an example of such an interface).
675
In order to determine that the description of the actions of a TSFI is
complete, the evaluator should review the rest of the interface description
(parameter descriptions, error messages, etc.) to determine if the actions
described are accounted for. The evaluator should also analyse other
evidence provided for the evaluation (e.g., TOE design, security architecture
description, operational user guidance, implementation representation) to see
if there is evidence of actions that are described there but not in the
functional specification.
ADV_FSP.5.6C
The functional specification shall describe all direct error messages that
may result from an invocation of each TSFI.
ADV_FSP.5-8
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes all errors messages resulting from an
invocation of each TSFI.
676
Errors can take many forms, depending on the interface being described. For
an API, the interface itself may return an error code; set a global error
condition, or set a certain parameter with an error code. For a configuration
file, an incorrectly configured parameter may cause an error message to be
written to a log file. For a hardware PCI card, an error condition may raise a
signal on the bus, or trigger an exception condition to the CPU.
677
Errors (and the associated error messages) come about through the
invocation of an interface. The processing that occurs in response to the
interface invocation may encounter error conditions, which trigger (through
an implementation-specific mechanism) an error message to be generated. In
some instances this may be a return value from the interface itself; in other
instances a global value may be set and checked after the invocation of an
interface. It is likely that a TOE will have a number of low-level error
messages that may result from fundamental resource conditions, such as
“disk full” or “resource locked”. While these error messages may map to a
large number of TSFI, they could be used to detect instances where detail
from an interface description has been omitted. For instance, a TSFI that
produces a “disk full” message, but has no obvious description of why that
TSFI should cause an access to the disk in its description of actions, might
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cause the evaluator to examine other evidence (ADV_ARC, ADV_TDS)
related that TSFI to determine if the description is complete and accurate.
678
The evaluator determines that, for each TSFI, the exact set of error messages
that can be returned on invoking that interface can be determined. The
evaluator reviews the evidence provided for the interface to determine if the
set of errors seems complete. They cross-check this information with other
evidence provided for the evaluation (e.g., TOE design, security architecture
description, operational user guidance, implementation representation) to
ensure that there are no errors steaming from processing mentioned that are
not included in the functional specification.
ADV_FSP.5-9
The evaluator shall examine the presentation of the TSFI to determine that it
completely and accurately describes the meaning of all errors associated with
each TSFI.
679
In order to determine accuracy, the evaluator must be able to understand
meaning of the error. For example, if an interface returns a numeric code of
0, 1, or 2, the evaluator would not be able to understand the error if the
functional specification only listed: “possible errors resulting from
invocation of the foo() interface are 0, 1, or 2”. Instead the evaluator checks
to ensure that the errors are described such as: “possible errors resulting from
invocation of the foo() interface are 0 (processing successful), 1 (file not
found), or 2 (incorrect filename specification)”.
680
In order to determine that the description of the errors due to invoking a
TSFI is complete, the evaluator examines the rest of the interface description
(parameter descriptions, actions, etc.) to determine if potential error
conditions that might be caused by using such an interface are accounted for.
The evaluator also checks other evidence provided for the evaluation (e.g.,
TOE design, security architecture description, operational user guidance,
implementation representation) to see if error processing related to the TSFI
is described there but is not described in the functional specification.
ADV_FSP.5.7C
The functional specification shall describe all error messages that do not
result from an invocation of a TSFI.
ADV_FSP.5-10
The evaluator shall examine the functional specification to determine that it
completely and accurately describes all errors messages that do not result
from an invocation of any TSFI.
681
This work unit complements work unit ADV_FSP.5-8, which describes
those error messages that result from an invocation of the TSFI. Taken
together, these work units cover all error messages that might be generated
by the TSF.
682
The evaluator assesses the completeness and accuracy of the functional
specification by comparing its contents to instances of error message
generation within the implementation representation. Most of these error
messages will have already been covered by work unit ADV_FSP.5-8.
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683
The error messages related to this work unit are typically those that are not
expected to be generated, but are constructed as a matter of good
programming practises. For example, a case statement that defines actions
resulting from each of a list of cases may end with a final else statement to
apply to anything that might not be expected; this practise ensures the TSF
does not get into an undefined state. However, it is not expected that the path
of execution would ever get to this else statement; therefore, any error
message generation within this else statement would never be generated.
Although it would not get generated, it must still be included in the
functional specification.
ADV_FSP.5.8C
The functional specification shall provide a rationale for each error
message contained in the TSF implementation yet does not result from an
invocation of a TSFI.
ADV_FSP.5-11
The evaluator shall examine the functional specification to determine that it
provides a rationale for each error message contained in the TSF
implementation yet does not result from an invocation of a TSFI.
684
The evaluator ensures that every error message found under work unit
ADV_FSP.5-10 contains a rationale describing why it cannot be invoked
from the TSFI.
685
As was described in the previous work unit, this rationale might be as
straightforward as the fact that the error message in question is provided for
completeness of execution logic and that it is never expected to be generated.
The evaluator ensures that the rationale for each such error message is
logical.
ADV_FSP.5.9C
The tracing shall demonstrate that the SFRs trace to TSFIs in the
functional specification.
ADV_FSP.5-12
The evaluator shall check that the tracing links the SFRs to the
corresponding TSFIs.
686
The tracing is provided by the developer to serve as a guide to which SFRs
are related to which TSFIs. This tracing can be as simple as a table; it is used
as input to the evaluator for use in the following work units, in which the
evaluator verifies its completeness and accuracy.
11.4.5.4
Action ADV_FSP.5.2E
ADV_FSP.5-13
The evaluator shall examine the functional specification to determine that it
is a complete instantiation of the SFRs.
687
To ensure that all SFRs are covered by the functional specification, as well
as the test coverage analysis, the evaluator may build upon the developer's
tracing (see ADV_FSP.5-12 a map between the TOE security functional
requirements and the TSFI. Note that this map may have to be at a level of
detail below the component or even element level of the requirements,
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because of operations (assignments, refinements, selections) performed on
the functional requirement by the ST author.
688
For example, the FDP_ACC.1 component contains an element with
assignments. If the ST contained, for instance, ten rules in the FDP_ACC.1
assignment, and these ten rules were covered by three different TSFI, it
would be inadequate for the evaluator to map FDP_ACC.1 to TSFI A, B, and
C and claim they had completed the work unit. Instead, the evaluator would
map FDP_ACC.1 (rule 1) to TSFI A; FDP_ACC.1 (rule 2) to TSFI B; etc. It
might also be the case that the interface is a wrapper interface (e.g., IOCTL),
in which case the mapping would need to be specific to certain set of
parameters for a given interface.
689
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that
they completely map those requirements to the TSFI. The analysis for those
requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST. It is also important to note that since
the parameters, actions, and error messages associated with TSFIs must be
fully specified, the evaluator should be able to determine if all aspects of an
SFR appear to be implemented at the interface level.
ADV_FSP.5-14
The evaluator shall examine the functional specification to determine that it
is an accurate instantiation of the SFRs.
690
For each functional requirement in the ST that results in effects visible at the
TSF boundary, the information in the associated TSFI for that requirement
specifies the required functionality described by the requirement. For
example, if the ST contains a requirement for access control lists, and the
only TSFI that map to that requirement specify functionality for Unix-style
protection bits, then the functionality specification is not accurate with
respect to the requirements.
691
The evaluator must recognise that for requirements that have little or no
manifestation at the TSF boundary (e.g., FDP_RIP) it is not expected that the
evaluator completely map those requirements to the TSFI. The analysis for
those requirements will be performed in the analysis for the TOE design
(ADV_TDS) when included in the ST.
11.4.6
Evaluation of sub-activity (ADV_FSP.6)
692
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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11.5
Implementation representation (ADV_IMP)
11.5.1
Evaluation of sub-activity (ADV_IMP.1)
11.5.1.1
Objectives
693
The objective of this sub-activity is to determine that the implementation
representation made available by the developer is suitable for use in other
analysis activities; suitability is judged by its conformance to the
requirements for this component.
11.5.1.2
Input
694
The evaluation evidence for this sub-activity is:
a)
the implementation representation;
b)
the documentation of the development tools, as resulting from
ALC_TAT ;
c)
TOE design description.
11.5.1.3
Application notes
695
The entire implementation representation is made available to ensure that
analysis activities are not curtailed due to lack of information. This does not,
however, imply that all of the representation is examined when the analysis
activities are being performed. This is likely impractical in almost all cases,
in addition to the fact that it most likely will not result in a higher-assurance
TOE vs. targeted sampling of the implementation representation. For this
sub-activity, this is even truer. It would not be productive for the evaluator to
spend large amounts of time verifying the requirements for one portion of the
implementation representation, and then use a different portion of the
implementation representation in performing analysis for other work units.
Therefore, the evaluator is encouraged to select the sample of the
implementation representation from the areas of the TOE that will be of most
interest during the analysis performed during work units from other families
(e.g. ATE_IND, AVA_VAN and ADV_INT).
11.5.1.4
Action ADV_IMP.1.1E
ADV_IMP.1.1C
The implementation representation shall define the TSF to a level of detail
such that the TSF can be generated without further design decisions.
ADV_IMP.1-1
The evaluator shall check that the implementation representation defines the
TSF to a level of detail such that the TSF can be generated without further
design decisions.
696
Source code or hardware diagrams and/or IC hardware design language code
or layout data that are used to build the actual hardware are examples of parts
of an implementation representation. The evaluator samples the
implementation representation to gain confidence that it is at the appropriate
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level and not, for instance, a pseudo-code level which requires additional
design decisions to be made. The evaluator is encouraged to perform a quick
check when first looking at the implementation representation to assure
themselves that the developer is on the right track. However, the evaluator is
also encourage to perform the bulk of this check while working on other
work units that call for examining the implementation; this will ensure the
sample examined for this work unit is relevant.
ADV_IMP.1.2C
The implementation representation shall be in the form used by the
development personnel.
ADV_IMP.1-2
The evaluator shall check that the implementation representation is in the
form used by development personnel.
697
The implementation representation is manipulated by the developer in form
that it suitable for transformation to the actual implementation. For instance,
the developer may work with files containing source code, which is
eventually compiled to become part of the TSF. The developer makes
available the implementation representation in the form they use, so that the
evaluator may use automated techniques in the analysis. This also increases
the confidence that the implementation representation examined is actually
the one used in the production of the TSF (as opposed to the case where it is
supplied in an alternate presentation format, such as a word processor
document). It should be noted that other forms of the implementation
representation may also be used by the developer; these forms are supplied
as well. The overall goal is to supply the evaluator with the information that
will maximise the evaluator's analysis efforts.
698
The evaluator samples the implementation representation to gain confidence
that it is the version that is usable by the developer. The sample is such that
the evaluator has assurance that all areas of the implementation
representation are in conformance with the requirement; however, a
complete examination of the entire implementation representation is
unnecessary.
699
Conventions in some forms of the implementation representation may make
it difficult or impossible to determine from just the implementation
representation itself what the actual result of the compilation or run-time
interpretation will be. For example, compiler directives for C language
compilers will cause the compiler to exclude or include entire portions of the
code.
700
Some forms of the implementation representation may require additional
information because they introduce significant barriers to understanding and
analysis. Examples include shrouded source code or source code that has
been obfuscated in other ways such that it prevents understanding and/or
analysis. These forms of implementation representation typically result from
by taking a version of the implementation representation that is used by the
TOE developer and running a shrouding or obfuscation program on it. While
the shrouded representation is what is compiled and may be closer to the
implementation (in terms of structure) than the original, un-shrouded
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representation, supplying such obfuscated code may cause significantly more
time to be spent in analysis tasks involving the representation. When such
forms of representation are created, the components require details on the
shrouding tools/algorithms used so that the un-shrouded representation can
be supplied, and the additional information can be used to gain confidence
that the shrouding process does not compromise any security mechanisms.
701
The evaluator samples the implementation representation to gain confidence
that all of the information needed to interpret the implementation
representation has been supplied. Note that the tools are among those
referenced by Tools and techniques (ALC_TAT) components. The evaluator
is encouraged to perform a quick check when first looking at the
implementation representation to assure themselves that the developer is on
the right track. However, the evaluator is also encouraged to perform the
bulk of this check while working on other work units that call for examining
the implementation; this will ensure the sample examined for this work unit
is relevant.
ADV_IMP.1.3C
The mapping between the TOE design description and the sample of the
implementation representation shall demonstrate their correspondence.
ADV_IMP.1-3
The evaluator shall examine the mapping between the TOE design
description and the sample of the implementation representation to determine
that it is accurate.
702
The evaluator augments the determination of existence (specified in work
unit ADV_IMP.1-1) by verifying the accuracy of a portion of the
implementation representation and the TOE design description. For parts of
the TOE design description that are interesting, the evaluator would verify
the implementation representation accurately reflects the description
provided in the TOE design description.
703
For example, the TOE design description might identify a login module that
is used to identify and authenticate users. If user authentication is sufficiently
significant, the evaluator would verify that the corresponding code in fact
implements that service as described in the TOE design description. It might
also be worthwhile to verify that the code accepts the parameters as
described in the functional specification.
704
It is worth pointing out the developer must choose whether to perform the
mapping for the entire implementation representation, thereby guaranteeing
that the chosen sample will be covered, or waiting for the sample to be
chosen before performing the mapping. The first option is likely more work,
but may be completed before the evaluation begins. The second option is less
work, but will produce a suspension of evaluation activity while the
necessary evidence is being produced.
11.5.2
Evaluation of sub-activity (ADV_IMP.2)
705
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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11.6
TSF internals (ADV_INT)
11.6.1
Evaluation of sub-activity (ADV_INT.1)
11.6.1.1
Objectives
706
The objective of this sub-activity is to determine whether the defined subset
of the TSF is designed and structured such that the likelihood of flaws is
reduced and that maintenance can be more readily performed without the
introduction of flaws.
11.6.1.2
Input
707
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE design description;
c)
the implementation representation (if ADV_IMP is part of the
claimed assurance);
d)
the architectural description;
e)
the documentation of the coding standards, as resulting from
ALC_TAT.
11.6.1.3
Application notes
708
The role of the internals description is to provide evidence of the structure of
the design and implementation of the TSF.
709
The structure of the design has two aspects: the constituent parts of the TSF
and the procedures used to design the TSF. In cases where the TSF is
designed in a manner consistent with the design represented by the TOE
design (see ADV_TDS), the assessment of the TSF design is obvious. In
cases where the design procedures (see ALC_TAT) are being followed, the
assessment of the TSF design procedures is similarly obvious.
710
In cases where the TSF is implemented using procedure-based software, this
structure is assessed on the basis of its modularity; the modules identified in
the internals description are the same as the modules identified in the TOE
design (TOE design (ADV_TDS)). A module consists of one or more source
code files that cannot be decomposed into smaller compilable units.
711
The use of the assignment in this component levies stricter constraints on the
identified subset of the TSF than on the remainder of the TSF. The TSF
subset that is explicitly identified in the assignment ADV_INT.1.1D. While
the entire TSF is to be designed using good engineering principles and result
in a well-structured TSF, only the specified subset is specifically analysed
for this characteristic. The evaluator determines that the developer's
application of coding standards result in a TSF that is understandable.
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712
The primary goal of this component is to ensure the TSF subset's
implementation representation is understandable to facilitate maintenance
and analysis (of both the developer and evaluator).
11.6.1.4
Action ADV_INT.1.1E
ADV_INT.1.1C
The justification shall explain the characteristics used to judge the
meaning of “well-structured”.
ADV_INT.1-1
The evaluator shall examine the justification to determine that it identifies
the basis for determining whether the TSF is well-structured.
713
The evaluator verifies that the criteria for determining the characteristic of
being well-structured are clearly defined in the justification. Acceptable
criteria typically originate from industry standards for the technology
discipline. For example, procedural software that executes linearly is
traditionally viewed as well-structured if it adheres to software engineering
programming practises, such as those defined in the IEEE Standard (IEEE
Std 610.12-1990). For example, it would identify the criteria for the
procedural software portions of the TSF subset:
a)
the process used for modular decomposition
b)
coding standards used in the development of the implementation
c)
a description of the maximum acceptable level of intermodule
coupling exhibited by the TSF subset
d)
a description of the minimum acceptable level of cohesion exhibited
the modules of the TSF subset
714
For other types of technologies used in the TOE - such as non-procedural
software (e.g. object-oriented programming), widespread commodity
hardware (e.g. PC microprocessors), and special-purpose hardware (e.g.
smart-card processors) - the evaluation authority should be consulted for
determining the adequacy of criteria for being “well-structured”.
ADV_INT.1.2C
The TSF internals description shall demonstrate that the assigned subset
of the TSF is well-structured.
ADV_INT.1-2
The evaluator shall check the TSF internals description to determine that it
identifies the Assigned subset of the TSF.
715
This subset may be identified in terms of the internals of the TSF at any layer
of abstraction. For example, it may be in terms of the structural elements of
the TSF as identified in the TOE design (e.g. the audit subsystem), or in
terms of the implementation (e.g. encrypt.c and decrypt.c files, or the 6227
IC chip).
716
It is insufficient to identify this subset in terms of the claimed SFRs (e.g. the
portion of the TSF that provide anonymity as defined in FPR_ANO.2)
because this does not indicate where to focus the analysis.
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ADV_INT.1-3
The evaluator shall examine the TSF internals description to determine that
it demonstrates that the assigned TSF subset is well-structured.
717
The evaluator examines the internals description to ensure that it provides a
sound explanation of how the TSF subset meets the criteria from
ADV_INT.1-1
718
For example, it would explain how the procedural software portions of the
TSF subset meets the following:
a)
that there is a one-to-one correspondence between the modules
identified in the TSF subset and the modules described in the TOE
design (ADV_TDS)
b)
how the TSF design is a reflection of the modular decomposition
process
c)
a justification for all instances where the coding standards were not
used or met
d)
a justification for any coupling or cohesion outside the acceptable
bounds
11.6.1.5
Action ADV_INT.1.2E
ADV_INT.1-4
The evaluator shall determine that the TOE design for the assigned TSF
subset is well-structured.
719
The evaluator examines a sample of the TOE design to verify the accuracy of
the justification. For example, a sample of the TOE design is analysed to
determine its adherence to the design standards, etc. As with all areas where
the evaluator performs activities on a subset the evaluator provides a
justification of the sample size and scope
720
The description of the TOE's decomposition into subsystems and modules
will make the argument that the TSF subset is well-structured self-evident.
Verification that the procedures for structuring the TSF (as examined in
ALC_TAT) are being followed will make it self-evident that the TSF subset
is well-structured.
ADV_INT.1-5
The evaluator shall determine that the assigned TSF subset is wellstructured.
721
If ADV_IMP is not part of the claimed assurance, then this work unit is not
applicable and is therefore considered to be satisfied.
722
The evaluator examines a sample of the TSF subset to verify the accuracy of
the internals description. For example, a sample of the procedural software
portions of the TSF subset is analysed to determine its cohesion and
coupling, its adherence to the coding standards, etc. As with all areas where
the evaluator performs activities on a subset the evaluator provides a
justification of the sample size and scope.
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11.6.2
Evaluation of sub-activity (ADV_INT.2)
11.6.2.1
Objectives
723
The objective of this sub-activity is to determine whether the TSF is
designed and structured such that the likelihood of flaws is reduced and that
maintenance can be more readily performed without the introduction of
flaws.
11.6.2.2
Input
724
The evaluation evidence for this sub-activity is:
a)
the modular design description;
b)
the implementation representation (if ADV_IMP is part of the
claimed assurance));
c)
the TSF internals description;
d)
the documentation of the coding standards, as resulting from
ALC_TAT.
11.6.2.3
Application notes
725
The role of the internals description is to provide evidence of the structure of
the design and implementation of the TSF.
726
The structure of the design has two aspects: the constituent parts of the TSF
and the procedures used to design the TSF. In cases where the TSF is
designed in a manner consistent with the design represented by the TOE
design (see ADV_TDS), the assessment of the TSF design is obvious. In
cases where the design procedures (see ALC_TAT) are being followed, the
assessment of the TSF design procedures is similarly obvious.
727
In cases where the TSF is implemented using procedure-based software, this
structure is assessed on the basis of its modularity; the modules identified in
the internals description are the same as the modules identified in the TOE
design (TOE design (ADV_TDS)). A module consists of one or more source
code files that cannot be decomposed into smaller compilable units.
728
The primary goal of this component is to ensure the TSF's implementation
representation is understandable to facilitate maintenance and analysis (of
both the developer and evaluator).
11.6.2.4
Action ADV_INT.2.1E
ADV_INT.2.1C
The justification shall explain the characteristics used to judge the
meaning of “well-structured”.
ADV_INT.2-1
The evaluator shall examine the justification to determine that it identifies
the basis for determining whether the TSF is well-structured.
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729
The evaluator verifies that the criteria for determining the characteristic of
being well-structured are clearly defined in the justification. Acceptable
criteria typically originate from industry standards for the technology
discipline. For example, procedural software that executes linearly is
traditionally viewed as well-structured if it adheres to software engineering
programming practises, such as those defined in the IEEE Standard (IEEE
Std 610.12-1990). For example, it would identify the criteria for the
procedural software portions of the TSF:
a)
the process used for modular decomposition
b)
coding standards used in the development of the implementation
c)
a description of the maximum acceptable level of intermodule
coupling exhibited by the TSF
d)
a description of the minimum acceptable level of cohesion exhibited
the modules of the TSF
730
For other types of technologies used in the TOE - such as non-procedural
software (e.g. object-oriented programming), widespread commodity
hardware (e.g. PC microprocessors), and special-purpose hardware (e.g.
smart-card processors) - the evaluation authority should be consulted for
determining the adequacy of criteria for being “well-structured”.
ADV_INT.2.2C
The TSF internals description shall demonstrate that the entire TSF is
well-structured.
ADV_INT.2-2
The evaluator shall examine the TSF internals description to determine that
it demonstrates that the TSF is well-structured.
731
The evaluator examines the internals description to ensure that it provides a
sound explanation of how the TSF meets the criteria from ADV_INT.2-1
732
For example, it would explain how the procedural software portions of the
TSF meet the following:
a)
that there is a one-to-one correspondence between the modules
identified in the TSF and the modules described in the TOE design
(ADV_TDS)
b)
how the TSF design is a reflection of the modular decomposition
process
c)
a justification for all instances where the coding standards were not
used or met
d)
a justification for any coupling or cohesion outside the acceptable
bounds
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11.6.2.5
Action ADV_INT.2.2E
ADV_INT.2-3
The evaluator shall determine that the TOE design is well-structured.
733
The evaluator examines the TOE design of a sample of the TSF to verify the
accuracy of the justification. For example, a sample of the TOE design is
analysed to determine its adherence to the design standards, etc. As with all
areas where the evaluator performs activities on a subset the evaluator
provides a justification of the sample size and scope
734
The description of the TOE's decomposition into subsystems and modules
will make the argument that the TSF subset is well-structured self-evident.
Verification that the procedures for structuring the TSF (as examined in
ALC_TAT) are being followed will make it self-evident that the TSF subset
is well-structured.
ADV_INT.2-4
The evaluator shall determine that the TSF is well-structured.
735
If ADV_IMP is not part of the claimed assurance, then this work unit is not
applicable and is therefore considered to be satisfied.
736
The evaluator examines a sample of the TSF to verify the accuracy of the
internals description. For example, a sample of the procedural software
portions of the TSF is analysed to determine its cohesion and coupling, its
adherence to the coding standards, etc. As with all areas where the evaluator
performs activities on a subset the evaluator provides a justification of the
sample size and scope.
11.6.3
Evaluation of sub-activity (ADV_INT.3)
11.6.3.1
Input
737
The evaluation evidence for this sub-activity is:
a)
the modular design description;
b)
the implementation representation;
c)
the TSF internals description;
d)
the documentation of the coding standards, as resulting from
ALC_TAT.
11.6.3.2
Action ADV_INT.3.1E
11.6.3.3
Action ADV_INT.3.2E
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11.7
Security policy modelling (ADV_SPM)
11.7.1
Evaluation of sub-activity (ADV_SPM.1)
738
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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11.8
TOE design (ADV_TDS)
11.8.1
Evaluation of sub-activity (ADV_TDS.1)
11.8.1.1
Input
739
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
security architecture description;
d)
the TOE design.
11.8.1.2
Action ADV_TDS.1.1E
ADV_TDS.1.1C
The design shall describe the structure of the TOE in terms of subsystems.
ADV_TDS.1-1
The evaluator shall examine the TOE design to determine that the structure
of the entire TOE is described in terms of subsystems.
740
The evaluator ensures that all of the subsystems of the TOE are identified.
This description of the TOE will be used as input to work unit ADV_TDS.12, where the parts of the TOE that make up the TSF are identified. That is,
this requirement is on the entire TOE rather than on only the TSF.
741
The TOE (and TSF) may be described in multiple layers of abstraction (i.e.
subsystems and modules) Depending upon the complexity of the TOE, its
design may be described in terms of subsystems and modules, as described
in CC Part 3 Annex A.4, ADV_TDS: Subsystems and Modules. At this level
of assurance, the decomposition only need be at the “subsystem” level.
742
In performing this activity, the evaluator examines other evidence presented
for the TOE (e.g., ST, operator user guidance) to determine that the
description of the TOE in such evidence is consistent with the description
contained in the TOE design.
ADV_TDS.1.2C
The design shall identify all subsystems of the TSF.
ADV_TDS.1-2
The evaluator shall examine the TOE design to determine that all
subsystems of the TSF are identified.
743
In work unit ADV_TDS.1-1 all of the subsystems of the TOE were
identified, and a determination made that the non-TSF subsystems were
correctly characterised. Building on that work, the subsystems that were not
characterised as non-TSF subsystems should be precisely identified. The
evaluator determines that, of the hardware and software installed and
configured according to the Preparative procedures (AGD_PRE) guidance,
each subsystem has been accounted for as either one that is part of the TSF,
or one that is not.
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ADV_TDS.1.3C
The design shall describe the behaviour of each SFR-supporting or SFRnon-interfering TSF subsystem in sufficient detail to determine that it is
not SFR-enforcing.
ADV_TDS.1-3
The evaluator shall examine the TOE design to determine that each nonSFR-enforcing subsystem of the TSF is described such that the evaluator can
determine that the subsystem is non-SFR-enforcing.
744
Non-SFR-enforcing subsystems do not need to be described in detail as to
how they function in the system. However, the evaluator makes a
determination, based on the evidence provided by the developer, that the
subsystems that do not have high-level descriptions are non-SFR-enforcing
(that is, either SFR-supporting or SFR-non-interfering). Note that if the
developer provides a uniform level of detailed documentation then this work
unit will be largely satisfied, since the point of categorising the subsystems is
to allow the developer to provide less information for non-SFR-enforcing
subsystems than for SFR-enforcing subsystems.
745
An SFR-supporting subsystem is one that is depended on by an SFRenforcing subsystem in order to implement an SFR, but does not play as
direct a role as an SFR-supporting requirement. An SFR-non-interfering
subsystem is one that is not depended upon, in either a supporting or
enforcing role, to implement an SFR.
ADV_TDS.1.4C
The design shall summarise the SFR-enforcing behaviour of the SFRenforcing subsystems.
ADV_TDS.1-4
The evaluator shall examine the TOE design to determine that it provides a
complete, accurate, and high-level description of the SFR-enforcing
behaviour of the SFR-enforcing subsystems.
746
The developer may designate subsystems as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the subsystems have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the subsystems have the
appropriate information for their role (SFR-enforcing, etc.) in the TOE, and
to obtain the appropriate information from the developer should the
developer fail to provide the required information for a particular subsystem.
747
SFR-enforcing behaviour refers to how a subsystem provides the
functionality that implements an SFR. A high-level description need not refer
to specific data structures (although it may), but instead talks about more
general data flow, message flow, and control relationships within a
subsystem. The goal of these descriptions is to give the evaluator enough
information to understand how the SFR-enforcing behaviour is achieved.
Note that the evaluator should find unacceptable asserts of SFR-enforcement
in the TOE design documentation for this work unit. It should be noted that it
is the evaluator's determination with respect to what “high-level” means for a
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particular TOE, and the evaluator obtains enough information from the
developer to make a sound verdict for this work unit.
748
To determine completeness and accuracy, the evaluator examines other
information available (e.g., functional specification, security architecture
description, implementation representation). Descriptions of functionality in
these documents should be consistent with what is provided for evidence for
this work unit
ADV_TDS.1.5C
The design shall provide a description of the interactions among SFRenforcing subsystems of the TSF, and between the SFR-enforcing
subsystems of the TSF and other subsystems of the TSF.
ADV_TDS.1-5
The evaluator shall examine the TOE design to determine that interactions
between the subsystems of the TSF are described.
749
The goal of describing the interactions between the SFR-enforcing
subsystems and other subsystems is to help provide the reader a better
understanding of how the TSF performs it functions. These interactions do
not need to be characterised at the implementation level (e.g., parameters
passed from one routine in a subsystem to a routine in a different subsystem;
global variables; hardware signals (e.g., interrupts) from a hardware
subsystem to an interrupt-handling subsystem), but the data elements
identified for a particular subsystem that are going to be used by another
subsystem should be covered in this discussion. Any control relationships
between subsystems (e.g., a subsystem responsible for configuring a rule
base for a firewall system and the subsystem that actually implements these
rules) should also be described.
750
The evaluators should use their own judgement in assessing the
completeness of the description. If the reason for an interaction is unclear, or
if there are SFR-related interactions (discovered, for instance, in examining
the descriptions of subsystem behaviour) that do not appear to be described,
the evaluator ensures that this information is provided by the developer.
However, if the evaluator can determine that interactions among a particular
set of subsystems, while incompletely described by the developer, will not
aid in understanding the overall functionality nor security functionality
provided by the TSF, then the evaluator may choose to consider the
description sufficient, and not pursue completeness for its own sake.
ADV_TDS.1.6C
The mapping shall demonstrate that all behaviour described in the TOE
design is mapped to the TSFIs that invoke it.
ADV_TDS.1-6
The evaluator shall examine the TOE design to determine that it contains a
complete and accurate mapping from the TSFI described in the functional
specification to the subsystems of the TSF described in the TOE design.
751
The subsystems described in the TOE design provide a description of how
the TSF works at a detailed level for SFR-enforcing portions of the TSF, and
at a higher level for other portions of the TSF. The TSFI provide a
description of how the implementation is exercised. The evidence from the
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developer identifies the subsystem that is initially involved when an
operation is requested at the TSFI, and identify the various subsystems that
are primarily responsible for implementing the functionality. Note that a
complete “call tree” for each TSFI is not required for this work unit.
752
The evaluator assesses the completeness of the mapping by ensuring that all
of the TSFI map to at least one subsystem. The verification of accuracy is
more complex.
753
The first aspect of accuracy is that each TSFI is mapped to a subsystem at the
TSF boundary. This determination can be made by reviewing the subsystem
description and interactions, and from this information determining its place
in the architecture. The next aspect of accuracy is that the mapping makes
sense. For instance, mapping a TSFI dealing with access control to a
subsystem that checks passwords is not accurate. The evaluator should again
use judgement in making this determination. The goal is that this information
aids the evaluator in understanding the system and implementation of the
SFRs, and ways in which entities at the TSF boundary can interact with the
TSF. The bulk of the assessment of whether the SFRs are described
accurately by the subsystems is performed in other work units.
11.8.1.3
Action ADV_TDS.1.2E
ADV_TDS.1-7
The evaluator shall examine the TOE security functional requirements and
the TOE design, to determine that all ST security functional requirements are
covered by the TOE design.
754
The evaluator may construct a map between the TOE security functional
requirements and the TOE design. This map will likely be from a functional
requirement to a set of subsystems. Note that this map may have to be at a
level of detail below the subsystem or even element level of the
requirements, because of operations (assignments, refinements, selections)
performed on the functional requirement by the ST author.
755
For example, the FDP_ACC.1 Subset access control subsystem contains an
element with assignments. If the ST contained, for instance, ten rules in the
FDP_ACC.1 Subset access control assignment, and these ten rules were
implemented in specific places within fifteen modules, it would be
inadequate for the evaluator to map FDP_ACC.1 Subset access control to
one subsystem and claim the work unit had been completed. Instead, the
evaluator would map FDP_ACC.1 Subset access control (rule 1) to
subsystem A, behaviours x, y, and z; FDP_ACC.1 Subset access control
(rule 2) to subsystem A, behaviours x, p, and q; etc.
ADV_TDS.1-8
The evaluator shall examine the TOE design to determine that it is an
accurate instantiation of all security functional requirements.
756
The evaluator ensures that each security requirement listed in the TOE
security functional requirements section of the ST has a corresponding
design description in the TOE design that accurately details how the TSF
meets that requirement. This requires that the evaluator identify a collection
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of subsystems that are responsible for implementing a given functional
requirement, and then examine those subsystems to understand how the
requirement is implemented. Finally, the evaluator would assess whether the
requirement was accurately implemented.
757
As an example, if the ST requirements specified a role-based access control
mechanism, the evaluator would first identify the subsystems that contribute
to this mechanism's implementation. This could be done by in-depth
knowledge or understanding of the TOE design or by work done in the
previous work unit. Note that this trace is only to identify the subsystems,
and is not the complete analysis.
758
The next step would be to understand what mechanism the subsystems
implemented. For instance, if the design described an implementation of
access control based on UNIX-style protection bits, the design would not be
an accurate instantiation of those access control requirements present in the
ST example used above. If the evaluator could not determine that the
mechanism was accurately implemented because of a lack of detail, the
evaluator would have to assess whether all of the SFR-enforcing subsystems
have been identified, or if adequate detail had been provided for those
subsystems.
11.8.2
Evaluation of sub-activity (ADV_TDS.2)
11.8.2.1
Input
759
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
security architecture description;
d)
the TOE design.
11.8.2.2
Action ADV_TDS.2.1E
ADV_TDS.2.1C
The design shall describe the structure of the TOE in terms of subsystems.
ADV_TDS.2-1
The evaluator shall examine the TOE design to determine that the structure
of the entire TOE is described in terms of subsystems.
760
The evaluator ensures that all of the subsystems of the TOE are identified.
This description of the TOE will be used as input to work unit ADV_TDS.22, where the parts of the TOE that make up the TSF are identified. That is,
this requirement is on the entire TOE rather than on only the TSF.
761
The TOE (and TSF) may be described in multiple layers of abstraction (i.e.
subsystems and modules) Depending upon the complexity of the TOE, its
design may be described in terms of subsystems and modules, as described
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in CC Part 3 Annex A.4, ADV_TDS: Subsystems and Modules. At this level
of assurance, the decomposition only need be at the “subsystem” level.
762
In performing this activity, the evaluator examines other evidence presented
for the TOE (e.g., ST, operator user guidance) to determine that the
description of the TOE in such evidence is consistent with the description
contained in the TOE design.
ADV_TDS.2.2C
The design shall identify all subsystems of the TSF.
ADV_TDS.2-2
The evaluator shall examine the TOE design to determine that all
subsystems of the TSF are identified.
763
In work unit ADV_TDS.2-1 all of the subsystems of the TOE were
identified, and a determination made that the non-TSF subsystems were
correctly characterised. Building on that work, the subsystems that were not
characterised as non-TSF subsystems should be precisely identified. The
evaluator determines that, of the hardware and software installed and
configured according to the Preparative procedures (AGD_PRE) guidance,
each subsystem has been accounted for as either one that is part of the TSF,
or one that is not.
ADV_TDS.2.3C
The design shall describe the behaviour of each SFR non-interfering
subsystem of the TSF in detail sufficient to determine that it is SFR noninterfering.
ADV_TDS.2-3
The evaluator shall examine the TOE design to determine that each SFRnon-interfering subsystem of the TSF is described such that the evaluator can
determine that the subsystem is SFR-non-interfering.
764
SFR-non-interfering subsystems do not need to be described in detail as to
how they function in the system. However, the evaluator makes a
determination, based on the evidence provided by the developer, that the
subsystems that do not have detailed descriptions are SFR-non-interfering.
Note that if the developer provides a uniform level of detailed documentation
then this work unit will be largely satisfied, since the point of categorising
the subsystems is to allow the developer to provide less information for SFRnon-interfering subsystems than for SFR-enforcing and SFR-supporting
subsystems.
765
An SFR-non-interfering subsystem is one on which the SFR-enforcing and
SFR-supporting subsystems have no dependence; that is, they play no role in
implementing SFR functionality.
ADV_TDS.2.4C
The design shall describe the SFR-enforcing behaviour of the SFRenforcing subsystems.
ADV_TDS.2-4
The evaluator shall examine the TOE design to determine that it provides a
complete, accurate, and detailed description of the SFR-enforcing behaviour
of the SFR-enforcing subsystems.
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766
The developer may designate subsystems as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the subsystems have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the subsystems have the
appropriate information for their role (SFR-enforcing, etc.) in the TOE, and
to obtain the appropriate information from the developer should the
developer fail to provide the required information for a particular subsystem.
767
SFR-enforcing behaviour refers to how a subsystem provides the
functionality that implements an SFR. While not at the level of an
algorithmic description, a detailed description of behaviour typically
discusses how the functionality is provided in terms of what key data and
data structures are, what control relationships exist within a subsystem, and
how these elements work together to provide the SFR-enforcing behaviour.
Such a description also references SFR-supporting behaviour, which the
evaluator should consider in performing subsequent work units.
768
To determine completeness and accuracy, the evaluator examines other
information available (e.g., functional specification, security architecture
description, implementation representation). Descriptions of functionality in
these documents should be consistent with what is provided for evidence for
this work unit
ADV_TDS.2.5C
The design shall summarise the non-SFR-enforcing behaviour of the SFRenforcing subsystems.
ADV_TDS.2-5
The evaluator shall examine the TOE design to determine that it provides a
complete and accurate high-level description of the non-SFR-enforcing
behaviour of the SFR-enforcing subsystems.
769
The developer may designate subsystems as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the subsystems have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the subsystems have the
appropriate information for their role (SFR-enforcing, etc.) in the TOE, and
to obtain the appropriate information from the developer should the
developer fail to provide the required information for a particular subsystem.
770
In contrast to the previous work unit, this work unit calls for the evaluator to
assess the information provided for SFR-enforcing subsystems that is nonSFR-enforcing. The goal of this assessment is two-fold. First, it should
provide the evaluator greater understanding of the way each subsystem
works. Second, the evaluator determines that all SFR-enforcing behaviour
exhibited by a subsystem has been described. Unlike the previous work unit,
the information provided for non-SFR-enforcing behaviour does not have to
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be as detailed as that provided by the SFR-enforcing behaviour. For example,
data structures or data items that do not pertain to SFR-enforcing
functionality will likely not need to be described in detail, if at all. It is the
evaluator's determination, however, with respect to what “high-level” means
for a particular TOE, and the evaluator obtains enough information from the
developer (even if it turns out to be equivalent to information provided for
the parts of the subsystem that are SFR-enforcing) to make a sound verdict
for this work unit.
771
The evaluator is cautioned, however, that “perfect” assurance is not a goal
nor required by this work unit, so judgement will have to be exercised in
determine the amount and composition of the evidence required to make a
verdict on this work unit.
772
To determine completeness and accuracy, the evaluator examines other
information available (e.g., functional specification, security architecture
description, implementation representation). Descriptions of functionality in
these documents should be consistent with what is provided for evidence for
this work unit. In particular, the functional specification should be used to
determine that the behaviour required to implement the TSF Interfaces
described by the functional specification are completely described by the
subsystem, since the behaviour will either be SFR-enforcing or non-SFRenforcing.
ADV_TDS.2.6C
The design shall summarise the behaviour of the SFR-supporting
subsystems.
ADV_TDS.2-6
The evaluator shall examine the TOE design to determine that it provides a
complete and accurate high-level description of the behaviour of the SFRsupporting subsystems.
773
The developer may designate subsystems as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the subsystems have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the subsystems have the
appropriate information for their role (SFR-enforcing, etc.) in the TOE, and
to obtain the appropriate information from the developer should the
developer fail to provide the required information for a particular subsystem.
774
In contrast to the previous two work units, this work unit calls for the
developer to provide (and the evaluator to assess) information about SFR
supporting subsystems. Such subsystems should be referenced by the
descriptions of the SFR-enforcing subsystems, as well as by the descriptions
of interactions in work unit ADV_TDS.2-7. The goal of evaluator's
assessment, like that for the previous work unit, is two-fold. First, it should
provide the evaluator with an understanding of the way each SFR-supporting
subsystem works. Second, the evaluator determines that the behaviour is
described in enough detail so that the way in which the subsystem supports
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the SFR-enforcing behaviour is clear, and that the behaviour is not itself
SFR-enforcing. The information provided for SFR-supporting subsystem's
behaviour does not have to be as detailed as that provided by the SFRenforcing behaviour. For example, data structures or data items that do not
pertain to SFR-enforcing functionality will likely not need to be described in
detail, if at all. It is the evaluator's determination, however, with respect to
what “high-level” means for a particular TOE, and the evaluator obtains
enough information from the developer (even if it turns out to be equivalent
to information provided for the parts of the subsystem that are SFRenforcing) to make a sound verdict for this work unit.
775
The evaluator is cautions, however, that “perfect” assurance is not a goal nor
required by this work unit, so judgement will have to be exercised in
determine the amount and composition of the evidence required to make a
verdict on this work unit.
776
To determine completeness and accuracy, the evaluator examines other
information available (e.g., functional specification, security architecture
description, implementation representation). Descriptions of functionality in
these documents should be consistent with what is provided for evidence for
this work unit. In particular, the functional specification should be used to
determine that the behaviour required to implement the TSF Interfaces
described by the functional specification are completely described by the
subsystem.
ADV_TDS.2.7C
The design shall provide a description of the interactions among all
subsystems of the TSF.
ADV_TDS.2-7
The evaluator shall examine the TOE design to determine that interactions
between the subsystems of the TSF are described.
777
The goal of describing the interactions between the subsystems is to help
provide the reader a better understanding of how the TSF performs it
functions. These interactions do not need to be characterised at the
implementation level (e.g., parameters passed from one routine in a
subsystem to a routine in a different subsystem; global variables; hardware
signals (e.g., interrupts) from a hardware subsystem to an interrupt-handling
subsystem), but the data elements identified for a particular subsystem that
are going to be used by another subsystem should be covered in this
discussion. Any control relationships between subsystems (e.g., a subsystem
responsible for configuring a rule base for a firewall system and the
subsystem that actually implements these rules) should also be described.
778
It should be noted while the developer should characterise all interactions
between subsystems, the evaluators should use their own judgement in
assessing the completeness of the description. If the reason for an interaction
is unclear, or if there are SFR-related interactions (discovered, for instance,
in examining the descriptions of subsystem behaviour) that do not appear to
be described, the evaluator ensures that this information is provided by the
developer. However, if the evaluator can determine that interactions among a
particular set of subsystems, while incompletely described by the developer,
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will not aid in understanding the overall functionality nor security
functionality provided by the TSF, then the evaluator may choose to consider
the description sufficient, and not pursue completeness for its own sake.
ADV_TDS.2.8C
The mapping shall demonstrate that all behaviour described in the TOE
design is mapped to the TSFIs that invoke it.
ADV_TDS.2-8
The evaluator shall examine the TOE design to determine that it contains a
complete and accurate mapping from the TSFI described in the functional
specification to the subsystems of the TSF described in the TOE design.
779
The subsystems described in the TOE design provide a description of how
the TSF works at a detailed level for SFR-enforcing portions of the TSF, and
at a higher level for other portions of the TSF. The TSFI provide a
description of how the implementation is exercised. The evidence from the
developer identifies the subsystem that is initially involved when an
operation is requested at the TSFI, and identify the various subsystems that
are primarily responsible for implementing the functionality. Note that a
complete “call tree” for each TSFI is not required for this work unit.
780
The evaluator assesses the completeness of the mapping by ensuring that all
of the TSFI map to at least one subsystem. The verification of accuracy is
more complex.
781
The first aspect of accuracy is that each TSFI is mapped to a subsystem at the
TSF boundary. This determination can be made by reviewing the subsystem
description and interactions, and from this information determining its place
in the architecture. The next aspect of accuracy is that the mapping makes
sense. For instance, mapping a TSFI dealing with access control to a
subsystem that checks passwords is not accurate. The evaluator should again
use judgement in making this determination. The goal is that this information
aids the evaluator in understanding the system and implementation of the
SFRs, and ways in which entities at the TSF boundary can interact with the
TSF. The bulk of the assessment of whether the SFRs are described
accurately by the subsystems is performed in other work units.
11.8.2.3
Action ADV_TDS.2.2E
ADV_TDS.2-9
The evaluator shall examine the TOE security functional requirements and
the TOE design, to determine that all ST security functional requirements are
covered by the TOE design.
782
The evaluator may construct a map between the TOE security functional
requirements and the TOE design. This map will likely be from a functional
requirement to a set of subsystems. Note that this map may have to be at a
level of detail below the subsystem or even element level of the
requirements, because of operations (assignments, refinements, selections)
performed on the functional requirement by the ST author.
783
For example, the FDP_ACC.1 Subset access control subsystem contains an
element with assignments. If the ST contained, for instance, ten rules in the
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FDP_ACC.1 Subset access control assignment, and these ten rules were
implemented in specific places within fifteen modules, it would be
inadequate for the evaluator to map FDP_ACC.1 Subset access control to
one subsystem and claim the work unit had been completed. Instead, the
evaluator would map FDP_ACC.1 Subset access control (rule 1) to
subsystem A, behaviours x, y, and z; FDP_ACC.1 Subset access control
(rule 2) to subsystem A, behaviours x, p, and q; etc.
ADV_TDS.2-10
The evaluator shall examine the TOE design to determine that it is an
accurate instantiation of all security functional requirements.
784
The evaluator ensures that each security requirement listed in the TOE
security functional requirements section of the ST has a corresponding
design description in the TOE design that accurately details how the TSF
meets that requirement. This requires that the evaluator identify a collection
of subsystems that are responsible for implementing a given functional
requirement, and then examine those subsystems to understand how the
requirement is implemented. Finally, the evaluator would assess whether the
requirement was accurately implemented.
785
As an example, if the ST requirements specified a role-based access control
mechanism, the evaluator would first identify the subsystems that contribute
to this mechanism's implementation. This could be done by in-depth
knowledge or understanding of the TOE design or by work done in the
previous work unit. Note that this trace is only to identify the subsystems,
and is not the complete analysis.
786
The next step would be to understand what mechanism the subsystems
implemented. For instance, if the design described an implementation of
access control based on UNIX-style protection bits, the design would not be
an accurate instantiation of those access control requirements present in the
ST example used above. If the evaluator could not determine that the
mechanism was accurately implemented because of a lack of detail, the
evaluator would have to assess whether all of the SFR-enforcing subsystems
have been identified, or if adequate detail had been provided for those
subsystems.
11.8.3
Evaluation of sub-activity (ADV_TDS.3)
11.8.3.1
Objectives
787
The objective of this sub-activity is to determine whether the TOE design
provides a description of the TOE in terms of subsystems sufficient to
determine the TSF boundary, and provides a description of the TSF internals
in terms of modules (and optionally higher-level abstractions). It provides a
detailed description of the SFR-enforcing modules and enough information
about the SFR-supporting and SFR-non-interfering modules for the evaluator
to determine that the SFRs are completely and accurately implemented; as
such, the TOE design provides an explanation of the implementation
representation.
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11.8.3.2
Input
788
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
security architecture description;
d)
the TOE design.
11.8.3.3
Application notes
789
There are three types of activity that the evaluator must undertake with
respect to the TOE design. First, the evaluator determines that the TSF
boundary has been adequately described. Second, the evaluator determines
that the developer has provided documentation that conforms to the content
and presentation requirements for this subsystem, and that is consistent with
other documentation provided for the TOE. Finally, the evaluator must
analyse the design information provided for the SFR-enforcing modules (at a
detailed level) and the non-SFR-enforcing modules (at a less detailed level)
to understand how the system is implemented, and with that knowledge
ensure that the TSFI in the functional specification are adequately described,
and that the test information adequately tests the TSF (done in the Class
ATE: Tests work units).
790
It is important to note that while the developer is obligated to provide a
complete description of the TSF (although SFR-enforcing modules will have
more detail than the non-SFR-enforcing modules), the evaluator is expected
to use their judgement in performing their analysis. While the evaluator is
expected to look at every module, the detail to which they examine each
module may vary. The evaluator analyses each module in order to gain
enough understanding to determine the effect of the functionality of the
module on the security of the system, and the depth to which they need to
analyse the module may vary depending on the module's role in the system.
An important aspect of this analysis is that the evaluator should use the other
documentation provided (TSS, functional specification, security architecture
description, and the TSF internal document) in order to determine that the
functionality that is described is correct, and that the implicit designation of
non-SFR-enforcing modules (see below) is supported by their role in the
system architecture.
791
The developer may designate modules as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the modules have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the modules have the appropriate
information for their role (SFR-enforcing, etc.) in the TOE, and to obtain the
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appropriate information from the developer should the developer fail to
provide the required information for a particular module.
11.8.3.4
Action ADV_TDS.3.1E
ADV_TDS.3.1C
The design shall describe the structure of the TOE in terms of subsystems.
ADV_TDS.3-1
The evaluator shall examine the TOE design to determine that the structure
of the entire TOE is described in terms of subsystems.
792
The evaluator ensures that all of the subsystems of the TOE are identified.
This description of the TOE will be used as input to work unit ADV_TDS.32, where the parts of the TOE that make up the TSF are identified. That is,
this requirement is on the entire TOE rather than on only the TSF.
793
The TOE (and TSF) may be described in multiple layers of abstraction (i.e.
subsystems and modules) Depending upon the complexity of the TOE, its
design may be described in terms of subsystems and modules, as described
in CC Part 3 Annex A.4, ADV_TDS: Subsystems and Modules. For a very
simple TOE that can be described solely at the “module” level (see
ADV_TDS.3-2), this work unit is not applicable and therefore considered to
be satisfied.
794
In performing this activity, the evaluator examines other evidence presented
for the TOE (e.g., ST, operator user guidance) to determine that the
description of the TOE in such evidence is consistent with the description
contained in the TOE design.
ADV_TDS.3.2C
The design shall describe the TSF in terms of modules.
ADV_TDS.3-2
The evaluator shall examine the TOE design to determine that the entire
TSF is described in terms of modules.
795
The evaluator will examine the modules for specific properties in other work
units; in this work unit the evaluator determines that the modular description
covers the entire TSF, and not just a portion of the TSF. The evaluator uses
other evidence provided for the evaluation (e.g., functional specification,
architectural description) in making this determination. For example, if the
functional specification contains interfaces to functionality that does not
appear to be described in the TOE design description, it may be the case that
a portion of the TSF has not been included appropriately. Making this
determination will likely be an iterative process, where as more analysis is
done on the other evidence, more confidence can be gained with respect to
the completeness of the documentation.
796
Unlike subsystems, modules describe the implementation in a level of detail
that can serve as a guide to reviewing the implementation representation. A
description of a module should be such that one could create an
implementation of the module from the description, and the resulting
implementation would be 1) identical to the actual TSF implementation in
terms of the interfaces presented and used by the module, and 2)
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algorithmically identical to the TSF module. For instance, RFC 793 provides
a high-level description of the TCP protocol. It is necessarily implementation
independent. While it provides a wealth of detail, it is not a suitable design
description because it is not specific to an implementation. An actual
implementation can add to the protocol specified in the RFC, and
implementation choices (for instance, the use of global data vs. local data in
various parts of the implementation) may have an impact on the analysis that
is performed. The design description of the TCP module would list the
interfaces presented by the implementation (rather than just those defined in
RFC 793), as well as an algorithm description of the processing associated
with the modules implementing TCP (assuming it was part of the TSF).
ADV_TDS.3.3C
The design shall identify all subsystems of the TSF.
ADV_TDS.3-3
The evaluator shall examine the TOE design to determine that all
subsystems of the TSF are identified.
797
If the design is presented solely in terms of modules, then subsystems in
these requirements are equivalent to modules and the activity should be
performed at the module level.
798
In work unit ADV_TDS.3-1 all of the subsystems of the TOE were
identified, and a determination made that the non-TSF subsystems were
correctly characterised. Building on that work, the subsystems that were not
characterised as non-TSF subsystems should be precisely identified. The
evaluator determines that, of the hardware and software installed and
configured according to the Preparative procedures (AGD_PRE) guidance,
each subsystem has been accounted for as either one that is part of the TSF,
or one that is not.
ADV_TDS.3.4C
The design shall provide a description of each subsystem of the TSF.
ADV_TDS.3-4
The evaluator shall examine the TOE design to determine that each
subsystem of the TSF describes its role in the enforcement of SFRs described
in the ST.
799
If the design is presented solely in terms of modules, then this work unit will
be considered satisfied by the assessment done in subsequent work units; no
explicit action on the part of the evaluator is necessary in this case.
800
On systems that are complex enough to warrant a subsystem-level
description of the TSF in addition to the modular description, the goal of the
subsystem-level description is to give the evaluator context for the modular
description that follows. Therefore, the evaluator ensures that the subsystemlevel description contains a description of how the security functional
requirements are achieved in the design, but at a level of abstraction above
the modular description. This description should discuss the mechanisms
used at a level that is aligned with the module description; this will provide
the evaluators the road map needed to intelligently assess the information
contained in the module description. A well-written set of subsystem
descriptions will help guide the evaluator in determining the modules that are
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most important to examine, thus focusing the evaluation activity on the
portions of the TSF that have the most relevance with respect to the
enforcement of the SFRs.
801
The evaluator ensures that all subsystems of the TSF have a description.
While the description should focus on the role that the subsystem plays in
enforcing or supporting the implementation of the SFRs, enough information
must be present so that a context for understanding the SFR-related
functionality is provided.
ADV_TDS.3.5C
The design shall provide a description of the interactions among all
subsystems of the TSF.
ADV_TDS.3-5
The evaluator shall examine the TOE design to determine that interactions
between the subsystems of the TSF are described.
802
If the design is presented solely in terms of modules, then this work unit will
be considered satisfied by the assessment done in subsequent work units; no
explicit action on the part of the evaluator is necessary in this case.
803
On systems that are complex enough to warrant a subsystem-level
description of the TSF in addition to the modular description, the goal of
describing the interactions between the subsystems is to help provide the
reader a better understanding of how the TSF performs it functions. These
interactions do not need to be characterised at the implementation level (e.g.,
parameters passed from one routine in a subsystem to a routine in a different
subsystem; global variables; hardware signals (e.g., interrupts) from a
hardware subsystem to an interrupt-handling subsystem), but the data
elements identified for a particular subsystem that are going to be used by
another subsystem should be covered in this discussion. Any control
relationships between subsystems (e.g., a subsystem responsible for
configuring a rule base for a firewall system and the subsystem that actually
implements these rules) should also be described.
804
It should be noted while the developer should characterise all interactions
between subsystems, the evaluators should use their own judgement in
assessing the completeness of the description. If the reason for an interaction
is unclear, or if there are SFR-related interactions (discovered, for instance,
in examining the module-level documentation) that do not appear to be
described, the evaluator ensures that this information is provided by the
developer. However, if the evaluator can determine that interactions among a
particular set of subsystems, while incompletely described by the developer,
and a complete description will not aid in understanding the overall
functionality nor security functionality provided by the TSF, then the
evaluator may choose to consider the description sufficient, and not pursue
completeness for its own sake.
ADV_TDS.3.6C
The design shall provide a mapping from the subsystems of the TSF to the
modules of the TSF.
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ADV_TDS.3-6
The evaluator shall examine the TOE design to determine that the mapping
between the subsystems of the TSF to the modules of the TSF is complete.
805
If the design is presented solely in terms of modules, then this work unit is
considered satisfied.
806
For TOEs that are complex enough to warrant a subsystem-level description
of the TSF in addition to the modular description, the developer provides a
simple mapping showing how the modules of the TSF are allocated to the
subsystems. This will provide the evaluator a guide in performing their
module-level assessment. To determine completeness, the evaluator
examines each mapping and determines that all subsystems map to at least
one module, and that all modules map to exactly one subsystem.
ADV_TDS.3-7
The evaluator shall examine the TOE design to determine that the mapping
between the subsystems of the TSF to the modules of the TSF is accurate.
807
If the design is presented solely in terms of modules, then this work unit is
considered satisfied.
808
For TOEs that are complex enough to warrant a subsystem-level description
of the TSF in addition to the modular description, the developer provides a
simple mapping showing how the modules of the TSF are allocated to the
subsystems. This will provide the evaluator a guide in performing their
module-level assessment. The evaluator may choose to check the accuracy of
the mapping in conjunction with performing other work units. An
“inaccurate” mapping is one where the module is mistakenly associated with
a subsystem where its functions are not used within the subsystem. Because
the mapping is intended to be a guide supporting more detailed analysis, the
evaluator is cautioned to apply appropriate effort to this work unit.
Expending extensive evaluator resources verifying the accuracy of the
mapping is not necessary. Inaccuracies that lead to mis-understandings
related to the design that are uncovered as part of this or other work units are
the ones that should be associated with this work unit and corrected.
ADV_TDS.3.7C
The design shall describe each SFR-enforcing module in terms of its
purpose.
ADV_TDS.3-8
The evaluator shall examine the TOE design to determine that the
description of the purpose of each SFR-enforcing module is complete and
accurate.
809
The developer may designate modules as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the modules have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the modules have the appropriate
information for their role (SFR-enforcing, etc.) in the TOE, and to obtain the
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appropriate information from the developer should the developer fail to
provide the required information for a particular module.
810
The purpose of a module provides a description indicating what function the
module is fulfilling. A word of caution to evaluator is in order. The focus of
this work unit should be to provide the evaluator an understanding of how
the module works so that determinations can be made about the soundness of
the implementation of the SFRs, as well as to support architectural analysis
performed for ADV_ARC subsystems. As long as the evaluator has a sound
understanding of the module's operation, and its relationship to other
modules and the TOE as a whole, the evaluator should consider the objective
of the work achieved and not engage in a documentation exercise for the
developer (by requiring, for example, a complete algorithmic description for
a self-evident implementation representation).
ADV_TDS.3.8C
The design shall describe each SFR-enforcing module in terms of its SFRrelated interfaces, return values from those interfaces, and called
interfaces to other modules.
ADV_TDS.3-9
The evaluator shall examine the TOE design to determine that the
description of the interfaces presented by each SFR-enforcing module
contain an accurate and complete description of the SFR-related parameters,
the invocation conventions for each interface, and any values returned
directly by the interface.
811
The SFR-related interfaces of a module are those interfaces used by other
modules as a means to invoke the SFR-related operations provided, and to
provide inputs to or receive outputs from the module. The purpose in the
specification of these interfaces is to permit the exercise of them during
testing. Inter-module interfaces that are not SFR-related need not be
specified or described, since they are not a factor in testing. Likewise, other
internal interfaces that are not a factor in traversing SFR-related paths of
execution (such as those internal paths that are fixed).
812
SFR-related interfaces are described in terms of how they are invoked, and
any values that are returned. This description would include a list of SFRrelated parameters, and descriptions of these parameters. Note that global
data would also be considered parameters if used by the module (either as
inputs or outputs) when invoked. If a parameter were expected to take on a
set of values (e.g., a “flag” parameter), the complete set of values the
parameter could take on that would have an effect on module processing
would be specified. Likewise, parameters representing data structures are
described such that each field of the data structure is identified and
described. Note that different programming languages may have additional
“interfaces” that would be non-obvious; an example would be
operator/function overloading in C++. This “implicit interface” in the class
description would also be described as part of the low-level TOE design.
Note that although a module could present only one interface, it is more
common that a module presents a small set of related interfaces.
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813
In terms of the assessment of parameters (inputs and outputs) to a module,
any use of global data must also be considered. A module “uses” global data
if it either reads or writes the data. In order to assure the description of such
parameters (if used) is complete, the evaluator uses other information
provided about the module in the TOE design (interfaces, algorithmic
description, etc.), as well as the description of the particular set of global data
assessed in work unit ADV_TDS.3-8. For instance, the evaluator could first
determine the processing the module performs by examining its function and
interfaces presented (particularly the parameters of the interfaces). They
could then check to see if the processing appears to “touch” any of the global
data areas identified in the TOE design. The evaluator then determines that,
for each global data area that appears to be “touched”, that global data area is
listed as a means of input or output by the module the evaluator is
examining.
814
Invocation conventions are a programming-reference-type description that
one could use to correctly invoke a module's interface if one were writing a
program to make use of the module's functionality through that interface.
This includes necessary inputs and outputs, including any set-up that may
need to be performed with respect to global variables.
815
Values returned through the interface refer to values that are either passed
through parameters or messages; values that the function call itself returns in
the style of a “C” program function call; or values passed through global
means (such as certain error routines in *ix-style operating systems).
816
In order to assure the description is complete, the evaluator uses other
information provided about the module in the TOE design (e.g., algorithmic
description, global data used) to ensure that it appears all data necessary for
performing the functions of the module is presented to the module, and that
any values that other modules expect the module under examination to
provide are identified as being returned by the module. The evaluator
determines accuracy by ensuring that the description of the processing
matches the information listed as being passed to or from an interface.
817
Because the modules are at such a low level, it may be difficult determine
completeness and accuracy impacts from other documentation, such as
administrative guidance, the functional specification, the TSF internals, or
the security architecture description. However, the evaluator uses the
information present in those documents to the extent possible to help ensure
that the purpose is accurately and completely described. This analysis can be
aided by the analysis performed for the work units for the ADV_TDS.3.10C
element, which maps the TSFI in the functional specification to the modules
of the TSF.
ADV_TDS.3.9C
The design shall describe each SFR-supporting or SFR-non-interfering
module in terms of its purpose and interaction with other modules.
ADV_TDS.3-10
The evaluator shall examine the TOE design to determine that non-SFRsupporting modules are correctly categorised.
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818
In the cases where the developer has provided different amounts of
information for different modules, an implicit categorisation has been done.
That is, modules (for instance) with detail presented on their SFR-related
interfaces (see ADV_TDS.3.10C) are candidate SFR-enforcing modules,
although examination by the evaluator may lead to a determination that some
set of them are non-SFR-enforcing. Those with only a description of their
purpose and interaction with other modules (for instance) are “implicitly
categorised” as non-SFR-enforcing.
819
In these cases, a key focus of the evaluator for this work unit is attempting to
determine from the evidence provided for each module implicitly categorised
as non-SFR-enforcing and the evaluation information about other modules
(in the TOE design, the functional specification, the security architecture
description, and the administrative guidance), whether the module is indeed
non-SFR-enforcing. At this level of assurance some error should be
tolerated; the evaluator does not have to be absolutely sure that a given
module is non-SFR-enforcing, even though it is labelled as such. However, if
the evidence provided indicates that a non-SFR-enforcing module is SFRenforcing, the evaluator requests additional information from the developer
in order to resolve the apparent inconsistency. For instance, suppose the
documentation for Module A (an SFR-enforcing module) indicates that it
calls Module B to perform an access check on a certain type of construct.
When the evaluator examines the information associated with Module B,
they find that all the developer has provided is a purpose and a set of
interactions (thus implicitly categorising Module B as non-SFR-enforcing).
On examining the purpose and interactions from Module A, the evaluator
finds no mention of Module B performing any access checks, and Module A
is not listed as a module with which Module B interacts. At this point the
evaluator should approach the developer to resolve the discrepancies
between the information provided in Module A and that in Module B.
820
Another example would be where the evaluator examines the mapping of the
TSFI to the modules as provided by ADV_TDS.3.2D. This examination
shows that Module C is associated with an SFR requiring identification of
the user. Again, when the evaluator examines the information associated
with Module C, they find that all the developer has provided is a purpose and
a set of interactions (thus implicitly categorising Module C as non-SFRenforcing). Examining the purpose and interactions presented for Module C,
the evaluator is unable to determine why Module C, listed as mapping to a
TSFI concerned with user identification, would not be classified as SFRenforcing. Again, the evaluator should approach the developer to resolve this
discrepancy.
821
A final example from the opposite point of view. As before, the developer
has provided information associated with Module D consisting of a purpose
and a set of interactions (thus implicitly categorising Module D as non-SFRenforcing). The evaluator examines all of the evidence provided, including
the purpose and interactions for Module D. The purpose appears to give a
meaningful description of Module D's function in the TOE, the interactions
are consistent with that description, and there is nothing to indicate that
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Module D is SFR-enforcing. In this case, the evaluator should not demand
more information about Module D “just be to sure” it is correctly
categorised. The developer has met their obligations and the resulting
assurance the evaluator has in the implicit categorisation of Module D is (by
definition) appropriate for this assurance level.
ADV_TDS.3-11
The evaluator shall examine the TOE design to determine that the
description of the purpose of each non-SFR-supporting module is complete
and accurate.
822
The description of the purpose of a module indicates what function the
module is fulfilling. From the description, the evaluator should be able to
obtain a general idea of the module's role. In order to assure the description
is complete, the evaluator uses the information provided about the module's
interactions with other modules to assess whether the reasons for the module
being called are consistent with the module's purpose. If the interaction
description contains functionality that is not apparent from, or in conflict
with, the module's purpose, the evaluator needs to determine whether the
problem is one of accuracy or of completeness. The evaluator should be wary
of purposes that are too short, since meaningful analysis based on a onesentence purpose is likely to be impossible.
823
Because the modules are at such a low level, it may be difficult determine
completeness and accuracy impacts from other documentation, such as
administrative guidance, the functional specification, the security
architecture description, or the TSF internals document. However, the
evaluator uses the information present in those documents to the extent
possible to help ensure that the function is accurately and completely
described. This analysis can be aided by the analysis performed for the work
units for the ADV_TDS.3.10C element, which maps the TSFI in the
functional specification to the modules of the TSF.
ADV_TDS.3-12
The evaluator shall examine the TOE design to determine that the
description of a non-SFR-supporting module's interaction with other modules
is complete and accurate.
824
It is important to note that, in terms of the Part 3 requirement and this work
unit, the term interaction is intended to convey less rigour than interface. An
interaction does not need to be characterised at the implementation level
(e.g., parameters passed from one routine in a module to a routine in a
different module; global variables; hardware signals (e.g., interrupts) from a
hardware subsystem to an interrupt-handling subsystem), but the data
elements identified for a particular module that are going to be used by
another module should be covered in this discussion. Any control
relationships between modules (e.g., a module responsible for configuring a
rule base for a firewall system and the module that actually implements these
rules) should also be described.
825
A module's interaction with other modules can be captured in many ways.
The intent for the TOE design is to allow the evaluator to understand (in part
through analysis of module interactions) the role of the non-SFR-enforcing
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modules in the overall TOE design. Understanding of this role will aid the
evaluator in performing work unit ADV_TDS.3-15.
826
A module's interaction with other modules goes beyond just a call-tree-type
document. The interaction is described from a functional perspective of why
a module interacts with other modules. The module's purpose describes what
functions the module provides to other modules; the interactions should
describe what the module depends on from other modules in order to
accomplish this function.
827
Because the modules are at such a low level, it may be difficult determine
completeness and accuracy impacts from other documentation, such as
administrative guidance, the functional specification, the security
architecture description, or the TSF internals document. However, the
evaluator uses the information present in those documents to the extent
possible to help ensure that the interactions are accurately and completely
described.
ADV_TDS.3.10C
The mapping shall demonstrate that all behaviour described in the TOE
design is mapped to the TSFIs that invoke it.
ADV_TDS.3-13
The evaluator shall examine the TOE design to determine that it contains a
complete and accurate mapping from the TSFI described in the functional
specification to the modules of the TSF described in the TOE design.
828
The modules described in the TOE design provide a description of the
implementation of the TSF. The TSFI provide a description of how the
implementation is exercised. The evidence from the developer identifies the
module that is initially invoked when an operation is requested at the TSFI,
and identify the chain of modules invoked up to the module that is primarily
responsible for implementing the functionality. However, a complete call
tree for each TSFI is not required for this work unit. The cases in which more
than one module would have to be identified are where there are “entry
point” modules or wrapper modules that have no functionality other than
conditioning inputs or de-multiplexing an input. Mapping to one of these
modules would not provide any useful information to the evaluator.
829
The evaluator assesses the completeness of the mapping by ensuring that all
of the TSFI map to at least one module. The verification of accuracy is more
complex.
830
The first aspect of accuracy is that each TSFI is mapped to a module at the
TSF boundary. This determination can be made by reviewing the module
description and its interfaces/interactions. The next aspect of accuracy is that
each TSFI identifies a chain of modules between the initial module identified
and a module that is primarily responsible for implementing the function
presented at the TSF. Note that this may be the initial module, or there may
be several modules, depending on how much pre-conditioning of the inputs
is done. It should be noted that one indicator of a pre-conditioning module is
that it is invoked for a large number of the TSFI, where the TSFI are all of
similar type (e.g., system call). The final aspect of accuracy is that the
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mapping makes sense. For instance, mapping a TSFI dealing with access
control to a module that checks passwords is not accurate. The evaluator
should again use judgement in making this determination. The goal is that
this information aids the evaluator in understanding the system and
implementation of the SFRs, and ways in which entities at the TSF boundary
can interact with the TSF. The bulk of the assessment of whether the SFRs
are described accurately by the modules is performed in other work units.
11.8.3.5
Action ADV_TDS.3.2E
ADV_TDS.3-14
The evaluator shall examine the TOE security functional requirements and
the TOE design, to determine that all ST security functional requirements are
covered by the TOE design.
831
The evaluator may construct a map between the TOE security functional
requirements and the TOE design. This map will likely be from a functional
requirement to a set of subsystems. Note that this map may have to be at a
level of detail below the subsystem or even element level of the
requirements, because of operations (assignments, refinements, selections)
performed on the functional requirement by the ST author.
832
For example, the FDP_ACC.1 Subset access control subsystem contains an
element with assignments. If the ST contained, for instance, ten rules in the
FDP_ACC.1 Subset access control assignment, and these ten rules were
implemented in specific places within fifteen modules, it would be
inadequate for the evaluator to map FDP_ACC.1 Subset access control to
one subsystem and claim the work unit had been completed. Instead, the
evaluator would map FDP_ACC.1 Subset access control (rule 1) to
subsystem A, behaviours x, y, and z; FDP_ACC.1 Subset access control
(rule 2) to subsystem A, behaviours x, p, and q; etc.
ADV_TDS.3-15
The evaluator shall examine the TOE design to determine that it is an
accurate instantiation of all security functional requirements.
833
The evaluator ensures that each security requirement listed in the TOE
security functional requirements section of the ST has a corresponding
design description in the TOE design that accurately details how the TSF
meets that requirement. This requires that the evaluator identify a collection
of subsystems that are responsible for implementing a given functional
requirement, and then examine those subsystems to understand how the
requirement is implemented. Finally, the evaluator would assess whether the
requirement was accurately implemented.
834
As an example, if the ST requirements specified a role-based access control
mechanism, the evaluator would first identify the subsystems that contribute
to this mechanism's implementation. This could be done by in-depth
knowledge or understanding of the TOE design or by work done in the
previous work unit. Note that this trace is only to identify the subsystems,
and is not the complete analysis.
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835
The next step would be to understand what mechanism the subsystems
implemented. For instance, if the design described an implementation of
access control based on UNIX-style protection bits, the design would not be
an accurate instantiation of those access control requirements present in the
ST example used above. If the evaluator could not determine that the
mechanism was accurately implemented because of a lack of detail, the
evaluator would have to assess whether all of the SFR-enforcing subsystems
have been identified, or if adequate detail had been provided for those
subsystems.
11.8.4
Evaluation of sub-activity (ADV_TDS.4)
11.8.4.1
Objectives
836
The objective of this sub-activity is to determine whether the TOE design
provides a description of the TOE in terms of subsystems sufficient to
determine the TSF boundary, and provides a description of the TSF internals
in terms of modules (and optionally higher-level abstractions). It provides a
detailed description of the SFR-enforcing and SFR-supporting modules and
enough information about the SFR-non-interfering modules for the evaluator
to determine that the SFRs are completely and accurately implemented; as
such, the TOE design provides an explanation of the implementation
representation.
11.8.4.2
Input
837
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
security architecture description;
d)
the TOE design.
11.8.4.3
Application notes
838
There are three types of activity that the evaluator must undertake with
respect to the TOE design. First, the evaluator determines that the TSF
boundary has been adequately described. Second, the evaluator determines
that the developer has provided documentation that conforms to the content
and presentation requirements this subsystem, and that is consistent with
other documentation provided for the TOE. Finally, the evaluator must
analyse the design information provided for the SFR-enforcing modules (at a
detailed level) and the non-SFR-enforcing modules (at a less detailed level)
to understand how the system is implemented, and with that knowledge
ensure that the TSFI in the functional specification are adequately described,
and that the test information adequately tests the TSF (done in the Class
ATE: Tests work units).
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11.8.4.4
Action ADV_TDS.4.1E
ADV_TDS.4.1C
The design shall describe the structure of the TOE in terms of subsystems.
ADV_TDS.4-1
The evaluator shall examine the TOE design to determine that the structure
of the entire TOE is described in terms of subsystems.
839
The evaluator ensures that all of the subsystems of the TOE are identified.
This description of the TOE will be used as input to work unit ADV_TDS.42, where the parts of the TOE that make up the TSF are identified. That is,
this requirement is on the entire TOE rather than on only the TSF.
840
The TOE (and TSF) may be described in multiple layers of abstraction (i.e.
subsystems and modules) Depending upon the complexity of the TOE, its
design may be described in terms of subsystems and modules, as described
in CC Part 3 Annex A.4, ADV_TDS: Subsystems and Modules. For a very
simple TOE that can be described solely at the “module” level (see
ADV_TDS.4-2), this work unit is not applicable and therefore considered to
be satisfied.
841
In performing this activity, the evaluator examines other evidence presented
for the TOE (e.g., ST, operator user guidance) to determine that the
description of the TOE in such evidence is consistent with the description
contained in the TOE design.
ADV_TDS.4.2C
The design shall describe the TSF in terms of modules, designating each
module as SFR-enforcing, SFR-supporting, or SFR-non-interfering.
ADV_TDS.4-2
The evaluator shall examine the TOE design to determine that the entire
TSF is described in terms of modules.
842
The evaluator will examine the modules for specific properties in other work
units; in this work unit the evaluator determines that the modular description
covers the entire TSF, and not just a portion of the TSF. The evaluator uses
other evidence provided for the evaluation (e.g., functional specification,
architectural description) in making this determination. For example, if the
functional specification contains interfaces to functionality that does not
appear to be described in the TOE design description, it may be the case that
a portion of the TSF has not been included appropriately. Making this
determination will likely be an iterative process, where as more analysis is
done on the other evidence, more confidence can be gained with respect to
the completeness of the documentation.
843
Unlike subsystems, modules describe the implementation in a level of detail
that can serve as a guide to reviewing the implementation representation. A
description of a module should be such that one could create an
implementation of the module from the description, and the resulting
implementation would be 1) identical to the actual TSF implementation in
terms of the interfaces presented and used by the module, and 2)
algorithmically identical to the TSF module. For instance, RFC 793 provides
a high-level description of the TCP protocol. It is necessarily implementation
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independent. While it provides a wealth of detail, it is not a suitable design
description because it is not specific to an implementation. An actual
implementation can add to the protocol specified in the RFC, and
implementation choices (for instance, the use of global data vs. local data in
various parts of the implementation) may have an impact on the analysis that
is performed. The design description of the TCP module would list the
interfaces presented by the implementation (rather than just those defined in
RFC 793), as well as an algorithm description of the processing associated
with the modules implementing TCP (assuming it was part of the TSF).
ADV_TDS.4-3
The evaluator shall check the TOE design to determine that the TSF
modules are identified as either SFR-enforcing, SFR-supporting, or SFRnon-interfering.
844
The purpose of designating each module (according to the role a particular
module plays in the enforcement of the SFRs) is to allow developers to
provide less information about the parts of the TSF that have little role in
security. It is always permissible for the developer to provide more
information or detail than the requirements demand, as might occur when the
information has been gathered outside the evaluation context). In such cases
the developer must still designate the modules as either SFR-enforcing, SFRsupporting, or SFR-non-interfering.
845
The accuracy of these designations is continuously reviewed as the
evaluation progresses. The concern is the mis-designation of modules as
being less important (and hence, having less information) than is really the
case. While blatant mis-designations may be immediately apparent (e.g.,
designating an authentication module as anything but SFR-enforcing when
User identification (FIA_UID) is one of the SFRs being claimed), other misdesignations might not be discovered until the TSF is better understood. The
evaluator must therefore keep in mind that these designations are the
developer's initial best effort, but are subject to change. Further guidance is
provided under work unit ADV_TDS.4-16, which examines the accuracy of
these designations.
ADV_TDS.4.3C
The design shall identify all subsystems of the TSF.
ADV_TDS.4-4
The evaluator shall examine the TOE design to determine that all
subsystems of the TSF are identified.
846
If the design is presented solely in terms of modules, then subsystems in
these requirements are equivalent to modules and the activity should be
performed at the module level.
847
In work unit ADV_TDS.4-1 all of the subsystems of the TOE were
identified, and a determination made that the non-TSF subsystems were
correctly characterised. Building on that work, the subsystems that were not
characterised as non-TSF subsystems should be precisely identified. The
evaluator determines that, of the hardware and software installed and
configured according to the Preparative procedures (AGD_PRE) guidance,
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each subsystem has been accounted for as either one that is part of the TSF,
or one that is not.
ADV_TDS.4.4C
The design shall provide a description of each subsystem of the TSF.
ADV_TDS.4-5
The evaluator shall examine the TOE design to determine that each
subsystem of the TSF describes its role in the enforcement of SFRs described
in the ST.
848
If the design is presented solely in terms of modules, then this work unit will
be considered satisfied by the assessment done in subsequent work units; no
explicit action on the part of the evaluator is necessary in this case.
849
On systems that are complex enough to warrant a subsystem-level
description of the TSF in addition to the modular description, the goal of the
subsystem-level description is to give the evaluator context for the modular
description that follows. Therefore, the evaluator ensures that the subsystemlevel description contains a description of how the security functional
requirements are achieved in the design, but at a level of abstraction above
the modular description. This description should discuss the mechanisms
used at a level that is aligned with the module description; this will provide
the evaluators the road map needed to intelligently assess the information
contained in the module description. A well-written set of subsystem
descriptions will help guide the evaluator in determining the modules that are
most important to examine, thus focusing the evaluation activity on the
portions of the TSF that have the most relevance with respect to the
enforcement of the SFRs.
850
The evaluator ensures that all subsystems of the TSF have a description.
While the description should focus on the role that the subsystem plays in
enforcing or supporting the implementation of the SFRs, enough information
must be present so that a context for understanding the SFR-related
functionality is provided.
ADV_TDS.4.5C
The design shall provide a description of the interactions among all
subsystems of the TSF.
ADV_TDS.4-6
The evaluator shall examine the TOE design to determine that interactions
between the subsystems of the TSF are described.
851
If the design is presented solely in terms of modules, then this work unit will
be considered satisfied by the assessment done in subsequent work units; no
explicit action on the part of the evaluator is necessary in this case.
852
On systems that are complex enough to warrant a subsystem-level
description of the TSF in addition to the modular description, the goal of
describing the interactions between the subsystems is to help provide the
reader a better understanding of how the TSF performs it functions. These
interactions do not need to be characterised at the implementation level (e.g.,
parameters passed from one routine in a subsystem to a routine in a different
subsystem; global variables; hardware signals (e.g., interrupts) from a
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hardware subsystem to an interrupt-handling subsystem), but the data
elements identified for a particular subsystem that are going to be used by
another subsystem should be covered in this discussion. Any control
relationships between subsystems (e.g., a subsystem responsible for
configuring a rule base for a firewall system and the subsystem that actually
implements these rules) should also be described.
853
It should be noted while the developer should characterise all interactions
between subsystems, the evaluators should use their own judgement in
assessing the completeness of the description. If the reason for an interaction
is unclear, or if there are SFR-related interactions (discovered, for instance,
in examining the module-level documentation) that do not appear to be
described, the evaluator ensures that this information is provided by the
developer. However, if the evaluator can determine that interactions among a
particular set of subsystems, while incompletely described by the developer,
and a complete description will not aid in understanding the overall
functionality nor security functionality provided by the TSF, then the
evaluator may choose to consider the description sufficient, and not pursue
completeness for its own sake.
ADV_TDS.4.6C
The design shall provide a mapping from the subsystems of the TSF to the
modules of the TSF.
ADV_TDS.4-7
The evaluator shall examine the TOE design to determine that the mapping
between the subsystems of the TSF to the modules of the TSF is complete.
854
If the design is presented solely in terms of modules, then this work unit is
considered satisfied.
855
For TOEs that are complex enough to warrant a subsystem-level description
of the TSF in addition to the modular description, the developer provides a
simple mapping showing how the modules of the TSF are allocated to the
subsystems. This will provide the evaluator a guide in performing their
module-level assessment. To determine completeness, the evaluator
examines each mapping and determines that all subsystems map to at least
one module, and that all modules map to exactly one subsystem.
ADV_TDS.4-8
The evaluator shall examine the TOE design to determine that the mapping
between the subsystems of the TSF to the modules of the TSF is accurate.
856
If the design is presented solely in terms of modules, then this work unit is
considered satisfied.
857
For TOEs that are complex enough to warrant a subsystem-level description
of the TSF in addition to the modular description, the developer provides a
simple mapping showing how the modules of the TSF are allocated to the
subsystems. This will provide the evaluator a guide in performing their
module-level assessment. The evaluator may choose to check the accuracy of
the mapping in conjunction with performing other work units. An
“inaccurate” mapping is one where the module is mistakenly associated with
a subsystem where its functions are not used within the subsystem. Because
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the mapping is intended to be a guide supporting more detailed analysis, the
evaluator is cautioned to apply appropriate effort to this work unit.
Expending extensive evaluator resources verifying the accuracy of the
mapping is not necessary. Inaccuracies that lead to mis-understandings
related to the design that are uncovered as part of this or other work units are
the ones that should be associated with this work unit and corrected.
ADV_TDS.4.7C
The design shall describe each SFR-enforcing and SFR-supporting
module in terms of its purpose.
ADV_TDS.4-9
The evaluator shall examine the TOE design to determine that the
description of the purpose of each SFR-enforcing and SFR-supporting
module is complete and accurate.
858
The developer may designate modules as SFR-enforcing, SFR-supporting,
and SFR non-interfering, but these “tags” are used only to describe the
amount and type of information the developer must provide, and can be used
to limit the amount of information the developer has to develop if their
engineering process does not produce the documentation required. Whether
the modules have been categorised by the developer or not, it is the
evaluator's responsibility to determine that the modules have the appropriate
information for their role (SFR-enforcing, etc.) in the TOE, and to obtain the
appropriate information from the developer should the developer fail to
provide the required information for a particular module.
859
The purpose of a module provides a description indicating what function the
module is fulfilling. A word of caution to evaluator is in order. The focus of
this work unit should be to provide the evaluator an understanding of how
the module works so that determinations can be made about the soundness of
the implementation of the SFRs, as well as to support architectural analysis
performed for ADV_ARC subsystems. As long as the evaluator has a sound
understanding of the module's operation, and its relationship to other
modules and the TOE as a whole, the evaluator should consider the objective
of the work achieved and not engage in a documentation exercise for the
developer (by requiring, for example, a complete algorithmic description for
a self-evident implementation representation).
ADV_TDS.4.8C
The design shall describe each SFR-enforcing and SFR-supporting
module in terms of its SFR-related interfaces, return values from those
interfaces, and called interfaces to other modules.
ADV_TDS.4-10
The evaluator shall examine the TOE design to determine that the
description of the interfaces presented by each SFR-enforcing and SFRsupporting module contain an accurate and complete description of the SFRrelated parameters, the invocation conventions for each interface, and any
values returned directly by the interface.
860
The SFR-related interfaces of a module are those interfaces used by other
modules as a means to invoke the SFR-related operations provided, and to
provide inputs to or receive outputs from the module. The purpose in the
specification of these interfaces is to permit the exercise of them during
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testing. Inter-module interfaces that are not SFR-related need not be
specified or described, since they are not a factor in testing. Likewise, other
internal interfaces that are not a factor in traversing SFR-related paths of
execution (such as those internal paths that are fixed).
861
SFR-related interfaces are described in terms of how they are invoked, and
any values that are returned. This description would include a list of
parameters, and descriptions of these parameters. Note that global data
would also be considered parameters if used by the module (either as inputs
or outputs) when invoked. If a parameter were expected to take on a set of
values (e.g., a “flag” parameter), the complete set of values the parameter
could take on that would have an effect on module processing would be
specified. Likewise, parameters representing data structures are described
such that each field of the data structure is identified and described. Note that
different programming languages may have additional “interfaces” that
would be non-obvious; an example would be operator/function overloading
in C++. This “implicit interface” in the class description would also be
described as part of the low-level TOE design. Note that although a module
could present only one interface, it is more common that a module presents a
small set of related interfaces.
862
In terms of the assessment of parameters (inputs and outputs) to a module,
any use of global data must also be considered. A module “uses” global data
if it either reads or writes the data. In order to assure the description of such
parameters (if used) is complete, the evaluator uses other information
provided about the module in the TOE design (interfaces, algorithmic
description, etc.), as well as the description of the particular set of global data
assessed in work unit ADV_TDS.4-9. For instance, the evaluator could first
determine the processing the module performs by examining its function and
interfaces presented (particularly the parameters of the interfaces). They
could then check to see if the processing appears to “touch” any of the global
data areas identified in the TDS design. The evaluator then determines that,
for each global data area that appears to be “touched”, that global data area is
listed as a means of input or output by the module the evaluator is
examining.
863
Invocation conventions are a programming-reference-type description that
one could use to correctly invoke a module's interface if one were writing a
program to make use of the module's functionality through that interface.
This includes necessary inputs and outputs, including any set-up that may
need to be performed with respect to global variables.
864
Values returned through the interface refer to values that are either passed
through parameters or messages; values that the function call itself returns in
the style of a “C” program function call; or values passed through global
means (such as certain error routines in *ix-style operating systems).
865
In order to assure the description is complete, the evaluator uses other
information provided about the module in the TOE design (e.g., algorithmic
description, global data used) to ensure that it appears all data necessary for
performing the functions of the module is presented to the module, and that
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any values that other modules expect the module under examination to
provide are identified as being returned by the module. The evaluator
determines accuracy by ensuring that the description of the processing
matches the information listed as being passed to or from an interface.
866
Because the modules are at such a low level, it may be difficult determine
completeness and accuracy impacts from other documentation, such as
administrative guidance, the functional specification, the TSF internals, or
the security architecture description. However, the evaluator uses the
information present in those documents to the extent possible to help ensure
that the purpose is accurately and completely described. This analysis can be
aided by the analysis performed for the work units for the ADV_TDS.4.10C
element, which maps the TSFI in the functional specification to the modules
of the TSF.
ADV_TDS.4.9C
The design shall describe each SFR-non-interfering module in terms of its
purpose and interaction with other modules.
ADV_TDS.4-11
The evaluator shall examine the TOE design to determine that SFR-noninterfering modules are correctly categorised.
867
As mentioned in work unit ADV_TDS.4-3, less information is required
about modules that are SFR-non-interfering. A key focus of the evaluator for
this work unit is attempting to determine from the evidence provided for
each module implicitly categorised as SFR-non-interfering and the
evaluation (information about other modules in the TOE design, the
functional specification, the security architecture description, the
administrative guidance, the TSF internals document, and perhaps even the
implementation representation) whether the module is indeed SFR-noninterfering. At this level of assurance some error should be tolerated; the
evaluator does not have to be absolutely sure that a given module is SFRnon-interfering, even though it is labelled as such. However, if the evidence
provided indicates that a SFR-non-interfering module is SFR-enforcing or
SFR-supporting, the evaluator requests additional information from the
developer in order to resolve the apparent inconsistency. For example,
suppose the documentation for Module A (an SFR-enforcing module)
indicates that it calls Module B to perform an access check on a certain type
of construct. When the evaluator examines the information associated with
Module B, it is discovered that the only information the developer has
provided is a purpose and a set of interactions (thus implicitly categorising
Module B as non-SFR-enforcing). On examining the purpose and
interactions from Module A, the evaluator finds no mention of Module B
performing any access checks, and Module A is not listed as a module with
which Module B interacts. At this point the evaluator should approach the
developer to resolve the discrepancies between the information provided in
Module A and that in Module B.
868
Another example would be where the evaluator examines the mapping of the
TSFI to the modules as provided by ADV_TDS.4.2D. This examination
shows that Module C is associated with an SFR requiring identification of
the user. Again, when the evaluator examines the information associated
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with Module C, they find that all the developer has provided is a purpose and
a set of interactions (thus implicitly categorising Module C as SFR-noninterfering). Examining the purpose and interactions presented for Module C,
the evaluator is unable to determine why Module C, listed as mapping to a
TSFI concerned with user identification, would not be classified as SFRenforcing or SFR-supporting. Again, the evaluator should approach the
developer to resolve this discrepancy.
869
A final example illustrates the opposite situation. As before, the developer
has provided information associated with Module D consisting of a purpose
and a set of interactions (thus implicitly categorising Module D as SFR-noninterfering). The evaluator examines all of the evidence provided, including
the purpose and interactions for Module D. The purpose appears to give a
meaningful description of Module D's function in the TOE, the interactions
are consistent with that description, and there is nothing to indicate that
Module D is SFR-enforcing or SFR-supporting. In this case, the evaluator
should not demand more information about Module D “just be to sure” it is
correctly categorised. The developer has met the obligations and the resulting
assurance the evaluator has in the implicit categorisation of Module D is (by
definition) appropriate for this assurance level.
ADV_TDS.4-12
The evaluator shall examine the TOE design to determine that the
description of the purpose of each SFR-non-interfering module is complete
and accurate.
870
The description of the purpose of a module indicates what function the
module is fulfilling. From the description, the evaluator should be able to
obtain a general idea of the module's role. In order to assure the description
is complete, the evaluator uses the information provided about the module's
interactions with other modules to assess whether the reasons for the module
being called are consistent with the module's purpose. If the interaction
description contains functionality that is not apparent from, or in conflict
with, the module's purpose, the evaluator needs to determine whether the
problem is one of accuracy or of completeness. The evaluator should be wary
of purposes that are too short, since meaningful analysis based on a onesentence purpose is likely to be impossible.
871
Because the modules are at such a low level, it may be difficult determine
completeness and accuracy impacts from other documentation, such as
administrative guidance, the functional specification, the security
architecture description, or the TSF internals document. However, the
evaluator uses the information present in those documents to the extent
possible to help ensure that the function is accurately and completely
described. This analysis can be aided by the analysis performed for the work
units for the ADV_TDS.4.10C element, which maps the TSFI in the
functional specification to the modules of the TSF.
ADV_TDS.4-13
The evaluator shall examine the TOE design to determine that the
description of a SFR-non-interfering module's interaction with other modules
is complete and accurate.
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872
It is important to note that, in terms of the Part 3 requirement and this work
unit, the term interaction is intended to convey less rigour than interface. An
interaction does not need to be characterised at the implementation level
(e.g., parameters passed from one routine in a module to a routine in a
different module; global variables; hardware signals (e.g., interrupts) from a
hardware subsystem to an interrupt-handling subsystem), but the data
elements identified for a particular module that are going to be used by
another module should be covered in this discussion. Any control
relationships between modules (e.g., a module responsible for configuring a
rule base for a firewall system and the module that actually implements these
rules) should also be described.
873
A module's interaction with other modules can be captured in many ways.
The intent for the TOE design is to allow the evaluator to understand (in part
through analysis of module interactions) the role of the non-SFR-enforcing
modules in the overall TOE design. Understanding of this role will aid the
evaluator in performing work unit ADV_TDS.4-6.
874
A module's interaction with other modules goes beyond just a call-tree-type
document. The interaction is described from a functional perspective of why
a module interacts with other modules. The module's purpose describes what
functions the module provides to other modules; the interactions should
describe what the module depends on from other modules in order to
accomplish this function.
875
Because the modules are at such a low level, it may be difficult determine
completeness and accuracy impacts from other documentation, such as
administrative guidance, the functional specification, the security
architecture description, or the TSF internals document. However, the
evaluator uses the information present in those documents to the extent
possible to help ensure that the interactions are accurately and completely
described.
ADV_TDS.4.10C
The mapping shall demonstrate that all behaviour described in the TOE
design is mapped to the TSFIs that invoke it.
ADV_TDS.4-14
The evaluator shall examine the TOE design to determine that it contains a
complete and accurate mapping from the TSFI described in the functional
specification to the modules of the TSF described in the TOE design.
876
The modules described in the TOE design provide a description of the
implementation of the TSF. The TSFI provide a description of how the
implementation is exercised. The evidence from the developer identifies the
module that is initially invoked when an operation is requested at the TSFI,
and identify the chain of modules invoked up to the module that is primarily
responsible for implementing the functionality. However, a complete call
tree for each TSFI is not required for this work unit. The cases in which more
than one module would have to be identified are where there are “entry
point” modules or wrapper modules that have no functionality other than
conditioning inputs or de-multiplexing an input. Mapping to one of these
modules would not provide any useful information to the evaluator.
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877
The evaluator assesses the completeness of the mapping by ensuring that all
of the TSFI map to at least one module. The verification of accuracy is more
complex.
878
The first aspect of accuracy is that each TSFI is mapped to a module at the
TSF boundary. This determination can be made by reviewing the module
description and its interfaces/interactions. The next aspect of accuracy is that
each TSFI identifies a chain of modules between the initial module identified
and a module that is primarily responsible for implementing the function
presented at the TSF. Note that this may be the initial module, or there may
be several modules, depending on how much pre-conditioning of the inputs
is done. It should be noted that one indicator of a pre-conditioning module is
that it is invoked for a large number of the TSFI, where the TSFI are all of
similar type (e.g., system call). The final aspect of accuracy is that the
mapping makes sense. For instance, mapping a TSFI dealing with access
control to a module that checks passwords is not accurate. The evaluator
should again use judgement in making this determination. The goal is that
this information aids the evaluator in understanding the system and
implementation of the SFRs, and ways in which entities at the TSF boundary
can interact with the TSF. The bulk of the assessment of whether the SFRs
are described accurately by the modules is performed in other work units.
11.8.4.5
Action ADV_TDS.4.2E
ADV_TDS.4-15
The evaluator shall examine the TOE security functional requirements and
the TOE design, to determine that all ST security functional requirements are
covered by the TOE design.
879
The evaluator may construct a map between the TOE security functional
requirements and the TOE design. This map will likely be from a functional
requirement to a set of subsystems. Note that this map may have to be at a
level of detail below the subsystem or even element level of the
requirements, because of operations (assignments, refinements, selections)
performed on the functional requirement by the ST author.
880
For example, the FDP_ACC.1 Subset access control subsystem contains an
element with assignments. If the ST contained, for instance, ten rules in the
FDP_ACC.1 Subset access control assignment, and these ten rules were
implemented in specific places within fifteen modules, it would be
inadequate for the evaluator to map FDP_ACC.1 Subset access control to
one subsystem and claim the work unit had been completed. Instead, the
evaluator would map FDP_ACC.1 Subset access control (rule 1) to
subsystem A, behaviours x, y, and z; FDP_ACC.1 Subset access control
(rule 2) to subsystem A, behaviours x, p, and q; etc.
ADV_TDS.4-16
The evaluator shall examine the TOE design to determine that it is an
accurate instantiation of all security functional requirements.
881
The evaluator ensures that each security requirement listed in the TOE
security functional requirements section of the ST has a corresponding
design description in the TOE design that accurately details how the TSF
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meets that requirement. This requires that the evaluator identify a collection
of subsystems that are responsible for implementing a given functional
requirement, and then examine those subsystems to understand how the
requirement is implemented. Finally, the evaluator would assess whether the
requirement was accurately implemented.
882
As an example, if the ST requirements specified a role-based access control
mechanism, the evaluator would first identify the subsystems that contribute
to this mechanism's implementation. This could be done by in-depth
knowledge or understanding of the TOE design or by work done in the
previous work unit. Note that this trace is only to identify the subsystems,
and is not the complete analysis.
883
The next step would be to understand what mechanism the subsystems
implemented. For instance, if the design described an implementation of
access control based on UNIX-style protection bits, the design would not be
an accurate instantiation of those access control requirements present in the
ST example used above. If the evaluator could not determine that the
mechanism was accurately implemented because of a lack of detail, the
evaluator would have to assess whether all of the SFR-enforcing subsystems
have been identified, or if adequate detail had been provided for those
subsystems.
11.8.5
Evaluation of sub-activity (ADV_TDS.5)
884
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
11.8.6
Evaluation of sub-activity (ADV_TDS.6)
885
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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12
Class AGD: Guidance documents
12.1
Introduction
886
The purpose of the guidance document activity is to judge the adequacy of
the documentation describing how the user can handle the TOE in a secure
manner. Such documentation should take into account the various types of
users (e.g. those who accept, install, administrate or operate the TOE) whose
incorrect actions could adversely affect the security of the TOE or of their
own data.
887
The guidance documents class is subdivided into two families which are
concerned firstly with the preparative user guidance (all that has to be done
to transform the delivered TOE into its evaluated configuration in the
environment as described in the ST, i.e. accepting and installing the TOE)
and secondly with the operational user guidance (all that has to be done
during the operation of the TOE in its evaluated configuration, i.e. operation
and administration).
12.2
Application notes
888
The guidance documents activity applies to those functions and interfaces
which are related to the security of the TOE. The secure configuration of the
TOE is described in the ST.
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12.3
Operational user guidance (AGD_OPE)
12.3.1
Evaluation of sub-activity (AGD_OPE.1)
12.3.1.1
Objectives
889
The objectives of this sub-activity are to determine whether the user
guidance describes for each user role the security functionality and interfaces
provided by the TSF, provides instructions and guidelines for the secure use
of the TOE, addresses secure procedures for all modes of operation,
facilitates prevention and detection of insecure TOE states, or whether it is
misleading or unreasonable.
12.3.1.2
Input
890
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the TOE design, if applicable;
d)
the user guidance;
12.3.1.3
Action AGD_OPE.1.1E
AGD_OPE.1.1C
The operational user guidance shall describe, for each user role, the useraccessible functions and privileges that should be controlled in a secure
processing environment, including appropriate warnings.
AGD_OPE.1-1
The evaluator shall examine the operational user guidance to determine that
it describes, for each user role, the user-accessible functions and privileges
that should be controlled in a secure processing environment, including
appropriate warnings.
891
The configuration of the TOE may allow different user roles to have
dissimilar privileges in making use of the different functions of the TOE.
This means that some users are authorised to perform certain functions,
while other users may not be so authorised. These functions and privileges
should be described, for each user role, by the user guidance.
892
The user guidance identifies, for each user role, the functions and privileges
that must be controlled, the types of commands required for them, and the
reasons for such commands. The user guidance should contain warnings
regarding the use of these functions and privileges. Warnings should address
expected effects, possible side effects, and possible interactions with other
functions and privileges.
AGD_OPE.1.2C
The operational user guidance shall describe, for each user role, how to
use the available interfaces provided by the TOE in a secure manner.
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AGD_OPE.1-2
The evaluator shall examine the operational user guidance to determine that
it describes, for each user role, the secure use of the available interfaces
provided by the TOE.
893
The user guidance should provide advice regarding effective use of the TSF
(e.g. reviewing password composition practises, suggested frequency of user
file backups, discussion on the effects of changing user access privileges).
AGD_OPE.1.3C
The operational user guidance shall describe, for each user role, the
available functions and interfaces, in particular all security parameters
under the control of the user, indicating secure values as appropriate.
AGD_OPE.1-3
The evaluator shall examine the operational user guidance to determine that
it describes, for each user role, the available security functionality and
interfaces, in particular all security parameters under the control of the user,
indicating secure values as appropriate.
894
The user guidance should contain an overview of the security functionality
that is visible at the user interfaces.
895
The user guidance should identify and describe the purpose, behaviour, and
interrelationships of the security interfaces and functionality.
896
For each user-accessible interface, the user guidance should:
a)
describe the method(s) by which the interface is invoked (e.g.
command-line, programming-language system call, menu selection,
command button);
b)
describe the parameters to be set by the user, their particular
purposes, valid and default values, and secure and insecure use
settings of such parameters, both individually or in combination;
c)
describe the immediate TSF response, message, or code returned.
897
The evaluator should consider the functional specification and the ST to
determine that the TSF described in these documents is consistent to the
operational user guidance. The evaluator has to ensure that the operational
user guidance is complete to allow the secure use through the TSFI available
to all types of human users. The evaluator may, as an aid, prepare an
informal mapping between the guidance and these documents. Any
omissions in this mapping may indicate incompleteness.
AGD_OPE.1.4C
The operational user guidance shall, for each user role, clearly present
each type of security-relevant event relative to the user-accessible functions
that need to be performed, including changing the security characteristics
of entities under the control of the TSF.
AGD_OPE.1-4
The evaluator shall examine the operational user guidance to determine that
it describes, for each user role, each type of security-relevant event relative
to the user functions that need to be performed, including changing the
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security characteristics of entities under the control of the TSF and operation
following failure or operational error.
898
All types of security-relevant events are detailed for each user role, such that
each user knows what events may occur and what action (if any) he may
have to take in order to maintain security. Security-relevant events that may
occur during operation of the TOE (e.g. audit trail overflow, system crash,
updates to user records, such as when a user account is removed when the
user leaves the organisation) are adequately defined to allow user
intervention to maintain secure operation.
AGD_OPE.1.5C
The operational user guidance shall identify all possible modes of
operation of the TOE (including operation following failure or operational
error), their consequences and implications for maintaining secure
operation.
AGD_OPE.1-5
The evaluator shall examine the operational user guidance and other
evaluation evidence to determine that the guidance identifies all possible
modes of operation of the TOE (including, if applicable, operation following
failure or operational error), their consequences and implications for
maintaining secure operation.
899
Other evaluation evidence, particularly the functional specification, provide
an information source that the evaluator should use to determine that the
guidance contains sufficient guidance information.
900
If test documentation is included in the assurance package, then the
information provided in this evidence can also be used to determine that the
guidance contains sufficient guidance documentation. The detail provided in
the test steps can be used to confirm that the guidance provided is sufficient
for the use and administration of the TOE.
901
The evaluator should focus on a single human visible TSFI at a time,
comparing the guidance for securely using the TSFI with other evaluation
evidence, to determine that the guidance related to the TSFI is sufficient for
the secure usage (i.e. consistent with the SFRs) of that TSFI. The evaluator
should also consider the relationships between interfaces, searching for
potential conflicts.
AGD_OPE.1.6C
The operational user guidance shall, for each user role, describe the
security measures to be followed in order to fulfil the security objectives for
the operational environment as described in the ST.
AGD_OPE.1-6
The evaluator shall examine the operational user guidance to determine that
it describes, for each user role, the security measures to be followed in order
to fulfil the security objectives for the operational environment as described
in the ST.
902
The evaluator analyses the security objectives for the operational
environment in the ST and determines that for each user role, the relevant
security measures are described appropriately in the user guidance.
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903
The security measures described in the user guidance should include all
relevant external procedural, physical, personnel and connectivity measures.
904
Note that those measures relevant for secure installation of the TOE are
examined in Preparative procedures (AGD_PRE).
AGD_OPE.1.7C
The operational user guidance shall be clear and reasonable.
AGD_OPE.1-7
The evaluator shall examine the operational user guidance to determine that
it is clear.
905
The guidance is unclear if it can reasonably be misconstrued by an
administrator or user, and used in a way detrimental to the TOE, or to the
security provided by the TOE.
AGD_OPE.1-8
The evaluator shall examine the operational user guidance to determine that
it is reasonable.
906
The guidance is unreasonable if it makes demands on the TOE's usage or
operational environment that are inconsistent with the ST or unduly onerous
to maintain security.
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12.4
Preparative procedures (AGD_PRE)
12.4.1
Evaluation of sub-activity (AGD_PRE.1)
12.4.1.1
Objectives
907
The objective of this sub-activity is to determine whether the procedures and
steps for the secure preparation of the TOE have been documented and result
in a secure configuration.
12.4.1.2
Input
908
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE including its preparative procedures;
c)
the description of developer's delivery procedures, if applicable;
12.4.1.3
Application notes
909
The preparative procedures refer to all acceptance and installation
procedures, that are necessary to progress the TOE to the secure
configuration as described in the ST.
12.4.1.4
Action AGD_PRE.1.1E
AGD_PRE.1.1C
The preparative procedures shall describe all the steps necessary for secure
acceptance of the delivered TOE in accordance with the developer's
delivery procedures.
AGD_PRE.1-1
The evaluator shall check that the procedures necessary for the secure
acceptance of the delivered TOE have been provided.
910
If it is not anticipated by the developer's delivery procedures that acceptance
procedures will or can be applied, this work unit is not applicable, and is
therefore considered to be satisfied.
AGD_PRE.1-2
The evaluator shall examine the provided acceptance procedures to
determine that they describe the steps necessary for secure acceptance of the
TOE in accordance with the developer's delivery procedures.
911
The acceptance procedures should include as a minimum, that the user has to
check that all parts of the TOE as indicated in the ST have been delivered in
the correct version.
912
The acceptance procedures should reflect the steps the user has to perform in
order to accept the delivered TOE that are implied by the developer's
delivery procedures.
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913
The acceptance procedures should provide detailed information about the
following, if applicable:
a)
making sure that the delivered TOE is the complete evaluated
instance;
b)
detecting modification/masquerading of the delivered TOE.
AGD_PRE.1.2C
The preparative procedures shall describe all the steps necessary for secure
installation of the TOE and for the secure preparation of the operational
environment in accordance with the security objectives for the operational
environment as described in the ST.
AGD_PRE.1-3
The evaluator shall check that the procedures necessary for the secure
installation of the TOE have been provided.
914
If it is not anticipated that installation procedures will or can be applied for
the TOE and the operational environment (e.g. because the TOE may already
be delivered in an operational state and there are no requirements for the
environment) this work unit is not applicable, and is therefore considered to
be satisfied.
AGD_PRE.1-4
The evaluator shall examine the provided installation procedures to
determine that they describe the steps necessary for secure installation of the
TOE and the secure preparation of the operational environment in
accordance with the security objectives in the ST.
915
If it is not anticipated that installation procedures will or can be applied (e.g.
because the TOE may already be delivered in an operational state), this work
unit is not applicable, and is therefore considered to be satisfied.
916
The installation procedures should provide detailed information about the
following, if applicable:
a)
minimum system requirements for secure installation;
b)
requirements for the operational environment in accordance with the
security objectives provided by the ST;
c)
changing the installation specific security characteristics of entities
under the control of the TSF (for example parameters, settings,
passwords);
d)
handling exceptions and problems.
12.4.1.5
Action AGD_PRE.1.2E
AGD_PRE.1-5
The evaluator shall perform all user procedures necessary to prepare the
TOE to determine that the TOE and its operational environment can be
prepared securely using only the supplied preparative user guidance.
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917
Preparation requires the evaluator to advance the TOE from a deliverable
state to the state in which it is operational, including acceptance and
installation of the TOE, and enforcing the SFRs consistent with the security
objectives for the TOE specified in the ST.
918
The evaluator should follow only the developer's procedures and may
perform the activities that customers are usually expected to perform to
accept and install the TOE, using the supplied preparative guidance
documentation only. Any difficulties encountered during such an exercise
may be indicative of incomplete, unclear or unreasonable guidance.
919
This work unit may be performed in conjunction with the evaluation
activities under Independent testing (ATE_IND).
920
If it is known that the TOE will be used as a dependent component for a
composed TOE evaluation, then the evaluator should ensure that the
operational environment is satisfied by the base component used in the
composed TOE.
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13
Class ALC: Life-cycle support
13.1
Introduction
921
The purpose of the life-cycle support activity is to determine the adequacy of
the security procedures that the developer uses during the development and
maintenance of the TOE. These procedures include the life-cycle model used
by the developer, the configuration management, the security measures used
throughout TOE development, the tools used by the developer throughout
the life-cycle of the TOE, the handling of security flaws, and the delivery
activity.
922
Poorly controlled development and maintenance of the TOE can result in
vulnerabilities in the implementation. Conformance to a defined life-cycle
model can help to improve controls in this area. A measurable life-cycle
model used for the TOE can remove ambiguity in assessing the development
progress of the TOE.
923
The purpose of the configuration management activity is to assist the
consumer in identifying the evaluated TOE, to ensure that configuration
items are uniquely identified, and the adequacy of the procedures that are
used by the developer to control and track changes that are made to the TOE.
This includes details on what changes are tracked, how potential changes are
incorporated, and the degree to which automation is used to reduce the scope
for error.
924
Developer security procedures are intended to protect the TOE and its
associated design information from interference or disclosure. Interference in
the development process may allow the deliberate introduction of
vulnerabilities. Disclosure of design information may allow vulnerabilities to
be more easily exploited. The adequacy of the procedures will depend on the
nature of the TOE and the development process.
925
The use of well-defined development tools and the application of
implementation standards by the developer and by third parties involved in
the development process help to ensure that vulnerabilities are not
inadvertently introduced during refinement.
926
The flaw remediation activity is intended to track security flaws, to identify
corrective actions, and to distribute the corrective action information to TOE
users.
927
The purpose of the delivery activity is to judge the adequacy of the
documentation of the procedures used to ensure that the TOE is delivered to
the consumer without modification.
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13.2
CM capabilities (ALC_CMC)
13.2.1
Evaluation of sub-activity (ALC_CMC.1)
13.2.1.1
Objectives
928
The objectives of this sub-activity are to determine whether the developer
has clearly identified the TOE.
13.2.1.2
Input
929
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE suitable for testing.
13.2.1.3
Action ALC_CMC.1.1E
ALC_CMC.1.1C
The TOE shall be labelled with its unique reference.
ALC_CMC.1-1
The evaluator shall check that the TOE provided for evaluation is labelled
with its reference.
930
The evaluator should ensure that the TOE contains the unique reference
which is stated in the ST. This could be achieved through labelled packaging
or media, or by a label displayed by the operational TOE. This is to ensure
that it would be possible for consumers to identify the TOE (e.g. at the point
of purchase or use).
931
The TOE may provide a method by which it can be easily identified. For
example, a software TOE may display its name and version number during
the start up routine, or in response to a command line entry. A hardware or
firmware TOE may be identified by a part number physically stamped on the
TOE.
932
Alternatively, the unique reference provided for the TOE may be the
combination of the unique reference of each component from which the TOE
is comprised (e.g. in the case of a composed TOE).
ALC_CMC.1-2
The evaluator shall check that the TOE references used are consistent.
933
If the TOE is labelled more than once then the labels have to be consistent.
For example, it should be possible to relate any labelled guidance
documentation supplied as part of the TOE to the evaluated operational TOE.
This ensures that consumers can be confident that they have purchased the
evaluated version of the TOE, that they have installed this version, and that
they have the correct version of the guidance to operate the TOE in
accordance with its ST.
934
The evaluator also verifies that the TOE reference is consistent with the ST.
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935
If this work unit is applied to a composed TOE, the following will apply. The
composed IT TOE will not be labelled with its unique (composite) reference,
but only the individual components will be labelled with their appropriate
TOE reference. It would require further development for the IT TOE to be
labelled, i.e. during start-up and/or operation, with the composite reference.
If the composed TOE is delivered as the constituent component TOEs, then
the TOE items delivered will not contain the composite reference. However,
the composed TOE ST will include the unique reference for the composed
TOE and will identify the components comprising the composed TOE
through which the consumers will be able to determine whether they have
the appropriate items.
13.2.2
Evaluation of sub-activity (ALC_CMC.2)
13.2.2.1
Objectives
936
The objectives of this sub-activity are to determine whether the developer
uses a CM system that uniquely identifies all configuration items.
13.2.2.2
Input
937
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE suitable for testing;
c)
the configuration management documentation.
13.2.2.3
Application notes
938
This component contains an implicit evaluator action to determine that the
CM system is being used. As the requirements here are limited to
identification of the TOE and provision of a configuration list, this action is
already covered by, and limited to, the existing work units. At Evaluation of
sub-activity (ALC_CMC.3) the requirements are expanded beyond these two
items, and more explicit evidence of operation is required.
13.2.2.4
Action ALC_CMC.2.1E
ALC_CMC.2.1C
The TOE shall be labelled with its unique reference.
ALC_CMC.2-1
The evaluator shall check that the TOE provided for evaluation is labelled
with its reference.
939
The evaluator should ensure that the TOE contains the unique reference
which is stated in the ST. This could be achieved through labelled packaging
or media, or by a label displayed by the operational TOE. This is to ensure
that it would be possible for consumers to identify the TOE (e.g. at the point
of purchase or use).
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940
The TOE may provide a method by which it can be easily identified. For
example, a software TOE may display its name and version number during
the start up routine, or in response to a command line entry. A hardware or
firmware TOE may be identified by a part number physically stamped on the
TOE.
941
Alternatively, the unique reference provided for the TOE may be the
combination of the unique reference of each component from which the TOE
is comprised (e.g. in the case of a composed TOE).
ALC_CMC.2-2
The evaluator shall check that the TOE references used are consistent.
942
If the TOE is labelled more than once then the labels have to be consistent.
For example, it should be possible to relate any labelled guidance
documentation supplied as part of the TOE to the evaluated operational TOE.
This ensures that consumers can be confident that they have purchased the
evaluated version of the TOE, that they have installed this version, and that
they have the correct version of the guidance to operate the TOE in
accordance with its ST.
943
The evaluator also verifies that the TOE reference is consistent with the ST.
944
If this work unit is applied to a composed TOE, the following will apply. The
composed IT TOE will not be labelled with its unique (composite) reference,
but only the individual components will be labelled with their appropriate
TOE reference. It would require further development for the IT TOE to be
labelled, i.e. during start-up and/or operation, with the composite reference.
If the composed TOE is delivered as the constituent component TOEs, then
the TOE items delivered will not contain the composite reference. However,
the composed TOE ST will include the unique reference for the composed
TOE and will identify the components comprising the composed TOE
through which the consumers will be able to determine whether they have
the appropriate items.
ALC_CMC.2.2C
The CM documentation shall describe the method used to uniquely identify
the configuration items.
ALC_CMC.2-3
The evaluator shall examine the method of identifying configuration items
to determine that it describes how configuration items are uniquely
identified.
945
Procedures should describe how the status of each configuration item can be
tracked throughout the life-cycle of the TOE. The procedures may be
detailed in the CM plan or throughout the CM documentation. The
information included should describe:
a)
the method how each configuration item is uniquely identified, such
that it is possible to track versions of the same configuration item;
b)
the method how configuration items are assigned unique identifiers
and how they are entered into the CM system;
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c)
the method to be used to identify superseded versions of a
configuration item.
ALC_CMC.2.3C
The CM system shall uniquely identify all configuration items.
ALC_CMC.2-4
The evaluator shall examine the configuration items to determine that they
are identified in a way that is consistent with the CM documentation.
946
Assurance that the CM system uniquely identifies all configuration items is
gained by examining the identifiers for the configuration items. For both
configuration items that comprise the TOE, and drafts of configuration items
that are submitted by the developer as evaluation evidence, the evaluator
confirms that each configuration item possesses a unique identifier in a
manner consistent with the unique identification method that is described in
the CM documentation.
13.2.3
Evaluation of sub-activity (ALC_CMC.3)
13.2.3.1
Objectives
947
The objectives of this sub-activity are to determine whether the developer
uses a CM system that uniquely identifies all configuration items, and
whether the ability to modify these items is properly controlled.
13.2.3.2
Input
948
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE suitable for testing;
c)
the configuration management documentation.
13.2.3.3
Action ALC_CMC.3.1E
ALC_CMC.3.1C
The TOE shall be labelled with its unique reference.
ALC_CMC.3-1
The evaluator shall check that the TOE provided for evaluation is labelled
with its reference.
949
The evaluator should ensure that the TOE contains the unique reference
which is stated in the ST. This could be achieved through labelled packaging
or media, or by a label displayed by the operational TOE. This is to ensure
that it would be possible for consumers to identify the TOE (e.g. at the point
of purchase or use).
950
The TOE may provide a method by which it can be easily identified. For
example, a software TOE may display its name and version number during
the start up routine, or in response to a command line entry. A hardware or
firmware TOE may be identified by a part number physically stamped on the
TOE.
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951
Alternatively, the unique reference provided for the TOE may be the
combination of the unique reference of each component from which the TOE
is comprised (e.g. in the case of a composed TOE).
ALC_CMC.3-2
The evaluator shall check that the TOE references used are consistent.
952
If the TOE is labelled more than once then the labels have to be consistent.
For example, it should be possible to relate any labelled guidance
documentation supplied as part of the TOE to the evaluated operational TOE.
This ensures that consumers can be confident that they have purchased the
evaluated version of the TOE, that they have installed this version, and that
they have the correct version of the guidance to operate the TOE in
accordance with its ST.
953
The evaluator also verifies that the TOE reference is consistent with the ST.
954
If this work unit is applied to a composed TOE, the following will apply. The
composed IT TOE will not be labelled with its unique (composite) reference,
but only the individual components will be labelled with their appropriate
TOE reference. It would require further development for the IT TOE to be
labelled, i.e. during start-up and/or operation, with the composite reference.
If the composed TOE is delivered as the constituent component TOEs, then
the TOE items delivered will not contain the composite reference. However,
the composed TOE ST will include the unique reference for the composed
TOE and will identify the components comprising the composed TOE
through which the consumers will be able to determine whether they have
the appropriate items.
ALC_CMC.3.2C
The CM documentation shall describe the method used to uniquely identify
the configuration items.
ALC_CMC.3-3
The evaluator shall examine the method of identifying configuration items
to determine that it describes how configuration items are uniquely
identified.
955
Procedures should describe how the status of each configuration item can be
tracked throughout the life-cycle of the TOE. The procedures may be
detailed in the CM plan or throughout the CM documentation. The
information included should describe:
ALC_CMC.3.3C
a)
the method how each configuration item is uniquely identified, such
that it is possible to track versions of the same configuration item;
b)
the method how configuration items are assigned unique identifiers
and how they are entered into the CM system;
c)
the method to be used to identify superseded versions of a
configuration item.
The CM system shall uniquely identify all configuration items.
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ALC_CMC.3-4
The evaluator shall examine the configuration items to determine that they
are identified in a way that is consistent with the CM documentation.
956
Assurance that the CM system uniquely identifies all configuration items is
gained by examining the identifiers for the configuration items. For both
configuration items that comprise the TOE, and drafts of configuration items
that are submitted by the developer as evaluation evidence, the evaluator
confirms that each configuration item possesses a unique identifier in a
manner consistent with the unique identification method that is described in
the CM documentation.
ALC_CMC.3.4C
The CM system shall provide measures such that only authorised changes
are made to the configuration items.
ALC_CMC.3-5
The evaluator shall examine the CM access control measures described in
the CM plan to determine that they are effective in preventing unauthorised
access to the configuration items.
957
The evaluator may use a number of methods to determine that the CM access
control measures are effective. For example, the evaluator may exercise the
access control measures to ensure that the procedures could not be bypassed.
The evaluator may use the outputs generated by the CM system procedures
required by ALC_CMC.3.8C. The evaluator may also witness a
demonstration of the CM system to ensure that the access control measures
employed are operating effectively.
ALC_CMC.3.5C
The CM documentation shall include a CM plan.
ALC_CMC.3-6
The evaluator shall check that the CM documentation provided includes a
CM plan. The CM plan needs not to be a connected document, but it is
recommended that there is a single document that describes where the
various parts of the CM plan can be found. If the CM plan is no single
document, the list in the following work unit gives hints regarding which
context is expected.
ALC_CMC.3.6C
The CM plan shall describe how the CM system is used for the
development of the TOE.
ALC_CMC.3-7
The evaluator shall examine the CM plan to determine that it describes how
the CM system is used for the development of the TOE.
958
The descriptions contained in a CM plan include, if applicable:
a)
all activities performed in the TOE development that are subject to
configuration management procedures (e.g. creation, modification or
deletion of a configuration item, data-backup, archiving);
b)
which means (e.g. CM tools, forms) have to be made available;
c)
the usage of the CM tools: the necessary details for a user of the CM
system to be able to operate the CM tools correctly in order to
maintain the integrity of the TOE;
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d)
which other objects (development components, tools, assessment
environments, etc) are taken under CM control;
e)
the roles and responsibilities of individuals required to perform
operations on individual configuration items (different roles may be
identified for different types of configuration items (e.g. design
documentation or source code));
f)
how CM instances (e.g. change control boards, interface control
working groups) are introduced and staffed;
g)
the description of the change management;
h)
the procedures that are used to ensure that only authorised individuals
can make changes to configuration items;
i)
the procedures that are used to ensure that concurrency problems do
not occur as a result of simultaneous changes to configuration items;
j)
the evidence that is generated as a result of application of the
procedures. For example, for a change to a configuration item, the
CM system might record a description of the change, accountability
for the change, identification of all configuration items affected,
status (e.g. pending or completed), and date and time of the change.
This might be recorded in an audit trail of changes made or change
control records;
k)
the approach to version control and unique referencing of TOE
versions (e.g. covering the release of patches in operating systems,
and the subsequent detection of their application).
ALC_CMC.3.7C
The evidence shall demonstrate that all configuration items are being
maintained under the CM system.
ALC_CMC.3-8
The evaluator shall check that the configuration items identified in the
configuration list are being maintained by the CM system.
959
The CM system employed by the developer should maintain the integrity of
the TOE. The evaluator should check that for each type of configuration item
(e.g. design documents or source code modules) contained in the
configuration list there are examples of the evidence generated by the
procedures described in the CM plan. In this case, the approach to sampling
will depend upon the level of granularity used in the CM system to control
CM items. Where, for example, 10,000 source code modules are identified in
the configuration list, a different sampling strategy should be applied
compared to the case in which there are only 5, or even 1. The emphasis of
this activity should be on ensuring that the CM system is being operated
correctly, rather than on the detection of any minor error.
960
For guidance on sampling see A.2, Sampling.
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ALC_CMC.3.8C
The evidence shall demonstrate that the CM system is being operated in
accordance with the CM plan.
ALC_CMC.3-9
The evaluator shall check the CM documentation to ascertain that it includes
the CM system records identified by the CM plan.
961
The output produced by the CM system should provide the evidence that the
evaluator needs to be confident that the CM plan is being applied, and also
that all configuration items are being maintained by the CM system as
required by ALC_CMC.3.7C. Example output could include change control
forms, or configuration item access approval forms.
ALC_CMC.3-10
The evaluator shall examine the evidence to determine that the CM system
is being operated in accordance with the CM plan.
962
The evaluator should select and examine a sample of evidence covering each
type of CM-relevant operation that has been performed on a configuration
item (e.g. creation, modification, deletion, reversion to an earlier version) to
confirm that all operations of the CM system have been carried out in line
with documented procedures. The evaluator confirms that the evidence
includes all the information identified for that operation in the CM plan.
Examination of the evidence may require access to a CM tool that is used.
The evaluator may choose to sample the evidence.
963
For guidance on sampling see A.2, Sampling.
964
Further confidence in the correct operation of the CM system and the
effective maintenance of configuration items may be established by means of
interview with selected development staff. In conducting such interviews, the
evaluator should aim to gain a deeper understanding of how the CM system
is used in practise as well as to confirm that the CM procedures are being
applied as described in the CM documentation. Note that such interviews
should complement rather than replace the examination of documentary
evidence, and may not be necessary if the documentary evidence alone
satisfies the requirement. However, given the wide scope of the CM plan it is
possible that some aspects (e.g. roles and responsibilities) may not be clear
from the CM plan and records alone. This is one case where clarification
may be necessary through interviews.
965
It is expected that the evaluator will visit the development site in support of
this activity.
966
For guidance on site visits see A.4, Site Visits.
13.2.4
Evaluation of sub-activity (ALC_CMC.4)
13.2.4.1
Objectives
967
The objectives of this sub-activity are to determine whether the developer
has clearly identified the TOE and its associated configuration items, and
whether the ability to modify these items is properly controlled by automated
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tools, thus making the CM system less susceptible to human error or
negligence.
13.2.4.2
Input
968
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE suitable for testing;
c)
the configuration management documentation.
13.2.4.3
Action ALC_CMC.4.1E
ALC_CMC.4.1C
The TOE shall be labelled with its unique reference.
ALC_CMC.4-1
The evaluator shall check that the TOE provided for evaluation is labelled
with its reference.
969
The evaluator should ensure that the TOE contains the unique reference
which is stated in the ST. This could be achieved through labelled packaging
or media, or by a label displayed by the operational TOE. This is to ensure
that it would be possible for consumers to identify the TOE (e.g. at the point
of purchase or use).
970
The TOE may provide a method by which it can be easily identified. For
example, a software TOE may display its name and version number during
the start up routine, or in response to a command line entry. A hardware or
firmware TOE may be identified by a part number physically stamped on the
TOE.
971
Alternatively, the unique reference provided for the TOE may be the
combination of the unique reference of each component from which the TOE
is comprised (e.g. in the case of a composed TOE).
ALC_CMC.4-2
The evaluator shall check that the TOE references used are consistent.
972
If the TOE is labelled more than once then the labels have to be consistent.
For example, it should be possible to relate any labelled guidance
documentation supplied as part of the TOE to the evaluated operational TOE.
This ensures that consumers can be confident that they have purchased the
evaluated version of the TOE, that they have installed this version, and that
they have the correct version of the guidance to operate the TOE in
accordance with its ST.
973
The evaluator also verifies that the TOE reference is consistent with the ST.
974
If this work unit is applied to a composed TOE, the following will apply. The
composed IT TOE will not be labelled with its unique (composite) reference,
but only the individual components will be labelled with their appropriate
TOE reference. It would require further development for the IT TOE to be
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labelled, i.e. during start-up and/or operation, with the composite reference.
If the composed TOE is delivered as the constituent component TOEs, then
the TOE items delivered will not contain the composite reference. However,
the composed TOE ST will include the unique reference for the composed
TOE and will identify the components comprising the composed TOE
through which the consumers will be able to determine whether they have
the appropriate items.
ALC_CMC.4.2C
The CM documentation shall describe the method used to uniquely identify
the configuration items.
ALC_CMC.4-3
The evaluator shall examine the method of identifying configuration items
to determine that it describes how configuration items are uniquely
identified.
975
Procedures should describe how the status of each configuration item can be
tracked throughout the life-cycle of the TOE. The procedures may be
detailed in the CM plan or throughout the CM documentation. The
information included should describe:
a)
the method how each configuration item is uniquely identified, such
that it is possible to track versions of the same configuration item;
b)
the method how configuration items are assigned unique identifiers
and how they are entered into the CM system;
c)
the method to be used to identify superseded versions of a
configuration item.
ALC_CMC.4.3C
The CM system shall uniquely identify all configuration items.
ALC_CMC.4-4
The evaluator shall examine the configuration items to determine that they
are identified in a way that is consistent with the CM documentation.
976
Assurance that the CM system uniquely identifies all configuration items is
gained by examining the identifiers for the configuration items. For both
configuration items that comprise the TOE, and drafts of configuration items
that are submitted by the developer as evaluation evidence, the evaluator
confirms that each configuration item possesses a unique identifier in a
manner consistent with the unique identification method that is described in
the CM documentation.
ALC_CMC.4.4C
The CM system shall provide automated measures such that only
authorised changes are made to the configuration items.
ALC_CMC.4-5
The evaluator shall examine the CM access control measures described in
the CM plan (cf. ALC_CMC.4.6C) to determine that they are automated and
effective in preventing unauthorised access to the configuration items.
977
The evaluator may use a number of methods to determine that the CM access
control measures are effective. For example, the evaluator may exercise the
access control measures to ensure that the procedures could not be bypassed.
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The evaluator may use the outputs generated by the CM system procedures
required by ALC_CMC.4.10C. The evaluator may also witness a
demonstration of the CM system to ensure that the access control measures
employed are operating effectively.
ALC_CMC.4.5C
The CM system shall support the production of the TOE by automated
means.
ALC_CMC.4-6
The evaluator shall check the CM plan (cf. ALC_CMC.4.6C) for automated
procedures for supporting the production of the TOE.
978
The term “production” applies to those processes adopted by the developer to
progress the TOE from the implementation representation to a state
acceptable for delivery to the end customer.
979
The evaluator verifies the existence of automated production support
procedures within the CM plan.
980
The following are examples for automated means supporting the production
of the TOE:
−
a “make” tool (as provided with many software development tools) in
the case of a software TOE;
−
a tool ensuring automatically (for example by means of bar codes)
that only parts are combined which indeed belong together in the case
of a hardware TOE.
ALC_CMC.4-7
The evaluator shall examine the TOE production support procedures to
determine that they are effective in ensuring that a TOE is generated that
reflects its implementation representation.
981
The production support procedures should describe which tools have to be
used to produce the final TOE from the implementation representation in a
clearly defined way. The conventions, directives, or other necessary
constructs are described under ALC_TAT.
982
The evaluator determines that by following the production support
procedures the correct configuration items would be used to generate the
TOE. For example, in a software TOE this may include checking that the
automated production procedures ensure that all source files and related
libraries are included in the compiled object code. Moreover, the procedures
should ensure that compiler options and comparable other options are
defined uniquely. For a hardware TOE, this work unit may include checking
that the automatic production procedures ensure that the belonging parts are
built together and no parts are missing.
983
The customer can then be confident that the version of the TOE delivered for
installation is derived from the implementation representation in an
unambiguous way and implements the SFRs as described in the ST.
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984
The evaluator should bear in mind that the CM system need not necessarily
possess the capability to produce the TOE, but should provide support for the
process that will help reduce the probability of human error.
ALC_CMC.4.6C
The CM documentation shall include a CM plan.
ALC_CMC.4-8
The evaluator shall check that the CM documentation provided includes a
CM plan. The CM plan needs not to be a connected document, but it is
recommended that there is a single document that describes where the
various parts of the CM plan can be found. If the CM plan is no single
document, the list in the following work unit gives hints regarding which
context is expected.
ALC_CMC.4.7C
The CM plan shall describe how the CM system is used for the
development of the TOE.
ALC_CMC.4-9
The evaluator shall examine the CM plan to determine that it describes how
the CM system is used for the development of the TOE.
985
The descriptions contained in a CM plan include, if applicable:
a)
all activities performed in the TOE development that are subject to
configuration management procedures (e.g. creation, modification or
deletion of a configuration item, data-backup, archiving);
b)
which means (e.g. CM tools, forms) have to be made available;
c)
the usage of the CM tools: the necessary details for a user of the CM
system to be able to operate the CM tools correctly in order to
maintain the integrity of the TOE;
d)
the production support procedures;
e)
which other objects (development components, tools, assessment
environments, etc) are taken under CM control;
f)
the roles and responsibilities of individuals required to perform
operations on individual configuration items (different roles may be
identified for different types of configuration items (e.g. design
documentation or source code));
g)
how CM instances (e.g. change control boards, interface control
working groups) are introduced and staffed;
h)
the description of the change management;
i)
the procedures that are used to ensure that only authorised individuals
can make changes to configuration items;
j)
the procedures that are used to ensure that concurrency problems do
not occur as a result of simultaneous changes to configuration items;
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k)
the evidence that is generated as a result of application of the
procedures. For example, for a change to a configuration item, the
CM system might record a description of the change, accountability
for the change, identification of all configuration items affected,
status (e.g. pending or completed), and date and time of the change.
This might be recorded in an audit trail of changes made or change
control records;
l)
the approach to version control and unique referencing of TOE
versions (e.g. covering the release of patches in operating systems,
and the subsequent detection of their application).
ALC_CMC.4.8C
The CM plan shall describe the procedures used to accept modified or
newly created configuration items as part of the TOE.
ALC_CMC.4-10
The evaluator shall examine the CM plan to determine that it describes the
procedures used to accept modified or newly created configuration items as
parts of the TOE.
986
The descriptions of the acceptance procedures in the CM plan should include
the developer roles or individuals responsible for the acceptance and the
criteria to be used for acceptance. They should take into account all
acceptance situations that may occur, in particular:
a)
accepting an item into the CM system for the first time, in particular
inclusion of software, firmware and hardware components from other
manufacturers into the TOE (“integration”);
b)
moving configuration items to the next life-cycle phase at each stage
of the construction of the TOE (e.g. module, subsystem, system);
c)
subsequent to transports between different development sites.
987
If this work unit is applied to a dependent component that is going to be
integrated in a composed TOE, the CM plan should consider the control of
base components obtained by the dependent TOE developer.
988
When obtaining the components the evaluators are to verify the following:
a)
Transfer of each base component from the base component developer
to the integrator (dependent TOE developer) was performed in
accordance with the base component TOE's secure delivery
procedures, as reported in the base component TOE certification
report.
b)
The component received has the same identifiers as those stated in
the ST and Certification Report for the component TOE.
c)
All additional material required by a developer for composition
(integration) is provided. This is to include the necessary extract of
the component TOE's functional specification.
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ALC_CMC.4.9C
The evidence shall demonstrate that all configuration items are being
maintained under the CM system.
ALC_CMC.4-11
The evaluator shall check that the configuration items identified in the
configuration list are being maintained by the CM system.
989
The CM system employed by the developer should maintain the integrity of
the TOE. The evaluator should check that for each type of configuration item
(e.g. design documents or source code modules) contained in the
configuration list there are examples of the evidence generated by the
procedures described in the CM plan. In this case, the approach to sampling
will depend upon the level of granularity used in the CM system to control
CM items. Where, for example, 10,000 source code modules are identified in
the configuration list, a different sampling strategy should be applied
compared to the case in which there are only 5, or even 1. The emphasis of
this activity should be on ensuring that the CM system is being operated
correctly, rather than on the detection of any minor error.
990
For guidance on sampling see A.2, Sampling.
ALC_CMC.4.10C
The evidence shall demonstrate that the CM system is being operated in
accordance with the CM plan.
ALC_CMC.4-12
The evaluator shall check the CM documentation to ascertain that it includes
the CM system records identified by the CM plan.
991
The output produced by the CM system should provide the evidence that the
evaluator needs to be confident that the CM plan is being applied, and also
that all configuration items are being maintained by the CM system as
required by ALC_CMC.4.9C. Example output could include change control
forms, or configuration item access approval forms.
ALC_CMC.4-13
The evaluator shall examine the evidence to determine that the CM system
is being operated in accordance with the CM plan.
992
The evaluator should select and examine a sample of evidence covering each
type of CM-relevant operation that has been performed on a configuration
item (e.g. creation, modification, deletion, reversion to an earlier version) to
confirm that all operations of the CM system have been carried out in line
with documented procedures. The evaluator confirms that the evidence
includes all the information identified for that operation in the CM plan.
Examination of the evidence may require access to a CM tool that is used.
The evaluator may choose to sample the evidence.
993
For guidance on sampling see A.2, Sampling.
994
Further confidence in the correct operation of the CM system and the
effective maintenance of configuration items may be established by means of
interviews with selected development staff. In conducting such interviews,
the evaluator should aim to gain a deeper understanding of how the CM
system is used in practise as well as to confirm that the CM procedures are
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being applied as described in the CM documentation. Note that such
interviews should complement rather than replace the examination of
documentary evidence, and may not be necessary if the documentary
evidence alone satisfies the requirement. However, given the wide scope of
the CM plan it is possible that some aspects (e.g. roles and responsibilities)
may not be clear from the CM plan and records alone. This is one case where
clarification may be necessary through interviews.
995
It is expected that the evaluator will visit the development site in support of
this activity.
996
For guidance on site visits see A.4, Site Visits.
13.2.5
Evaluation of sub-activity (ALC_CMC.5)
13.2.5.1
Objectives
997
The objectives of this sub-activity are to determine whether the developer
has clearly identified the TOE and its associated configuration items, and
whether the ability to modify these items is properly controlled by automated
tools, thus making the CM system less susceptible to human error or
negligence.
13.2.5.2
Input
998
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the TOE suitable for testing;
c)
the configuration management documentation.
13.2.5.3
Action ALC_CMC.5.1E
ALC_CMC.5.1C
The TOE shall be labelled with its unique reference.
ALC_CMC.5-1
The evaluator shall check that the TOE provided for evaluation is labelled
with its reference.
999
The evaluator should ensure that the TOE contains the unique reference
which is stated in the ST. This could be achieved through labelled packaging
or media, or by a label displayed by the operational TOE. This is to ensure
that it would be possible for consumers to identify the TOE (e.g. at the point
of purchase or use).
1000
The TOE may provide a method by which it can be easily identified. For
example, a software TOE may display its name and version number during
the start up routine, or in response to a command line entry. A hardware or
firmware TOE may be identified by a part number physically stamped on the
TOE.
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1001
Alternatively, the unique reference provided for the TOE may be the
combination of the unique reference of each component from which the TOE
is comprised (e.g. in the case of a composed TOE).
ALC_CMC.5-2
The evaluator shall check that the TOE references used are consistent.
1002
If the TOE is labelled more than once then the labels have to be consistent.
For example, it should be possible to relate any labelled guidance
documentation supplied as part of the TOE to the evaluated operational TOE.
This ensures that consumers can be confident that they have purchased the
evaluated version of the TOE, that they have installed this version, and that
they have the correct version of the guidance to operate the TOE in
accordance with its ST.
1003
The evaluator also verifies that the TOE reference is consistent with the ST.
1004
If this work unit is applied to a composed TOE, the following will apply. The
composed IT TOE will not be labelled with its unique (composite) reference,
but only the individual components will be labelled with their appropriate
TOE reference. It would require further development for the IT TOE to be
labelled, i.e. during start-up and/or operation, with the composite reference.
If the composed TOE is delivered as the constituent component TOEs, then
the TOE items delivered will not contain the composite reference. However,
the composed TOE ST will include the unique reference for the composed
TOE and will identify the components comprising the composed TOE
through which the consumers will be able to determine whether they have
the appropriate items.
ALC_CMC.5.2C
The CM documentation shall describe the method used to uniquely identify
the configuration items.
ALC_CMC.5-3
The evaluator shall examine the method of identifying configuration items
to determine that it describes how configuration items are uniquely
identified.
1005
Procedures should describe how the status of each configuration item can be
tracked throughout the life-cycle of the TOE. The procedures may be
detailed in the CM plan or throughout the CM documentation. The
information included should describe:
a)
the method how each configuration item is uniquely identified, such
that it is possible to track versions of the same configuration item;
b)
the method how configuration items are assigned unique identifiers
and how they are entered into the CM system;
c)
the method to be used to identify superseded versions of a
configuration item.
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ALC_CMC.5.3C
The CM documentation shall justify that the acceptance procedures
provide for an adequate and appropriate review of changes to all
configuration items.
ALC_CMC.5-4
The evaluator shall examine the CM documentation to determine that it
justifies that the acceptance procedures provide for an adequate and
appropriate review of changes to all configuration items.
1006
The CM documentation should make it sufficiently clear that by following
the acceptance procedures only parts of adequate quality are incorporated
into the TOE.
ALC_CMC.5.4C
The CM system shall uniquely identify all configuration items.
ALC_CMC.5-5
The evaluator shall examine the configuration items to determine that they
are identified in a way that is consistent with the CM documentation.
1007
Assurance that the CM system uniquely identifies all configuration items is
gained by examining the identifiers for the configuration items. For both
configuration items that comprise the TOE, and drafts of configuration items
that are submitted by the developer as evaluation evidence, the evaluator
confirms that each configuration item possesses a unique identifier in a
manner consistent with the unique identification method that is described in
the CM documentation.
ALC_CMC.5.5C
The CM system shall provide automated measures such that only
authorised changes are made to the configuration items.
ALC_CMC.5-6
The evaluator shall examine the CM access control measures described in
the CM plan (cf. ALC_CMC.5.12C) to determine that they are automated
and effective in preventing unauthorised access to the configuration items.
1008
The evaluator may use a number of methods to determine that the CM access
control measures are effective. For example, the evaluator may exercise the
access control measures to ensure that the procedures could not be bypassed.
The evaluator may use the outputs generated by the CM system procedures
required by ALC_CMC.5.16C. The evaluator may also witness a
demonstration of the CM system to ensure that the access control measures
employed are operating effectively.
ALC_CMC.5.6C
The CM system shall support the production of the TOE by automated
means.
ALC_CMC.5-7
The evaluator shall check the CM plan (cf. ALC_CMC.5.12C) for
automated procedures for supporting the production of the TOE.
1009
The term “production” applies to those processes adopted by the developer to
progress the TOE from the implementation representation to a state
acceptable for delivery to the end customer.
1010
The evaluator verifies the existence of automated production support
procedures within the CM plan.
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1011
The following are examples for automated means supporting the production
of the TOE:
−
a “make” tool (as provided with many software development tools) in
the case of a software TOE;
−
a tool ensuring automatically (for example by means of bar codes)
that only parts are combined which indeed belong together in the case
of a hardware TOE.
ALC_CMC.5-8
The evaluator shall examine the TOE production support procedures to
determine that they are effective in ensuring that a TOE is generated that
reflects its implementation representation.
1012
The production support procedures should describe which tools have to be
used to produce the final TOE from the implementation representation in a
clearly defined way. The conventions, directives, or other necessary
constructs are described under ALC_TAT.
1013
The evaluator determines that by following the production support
procedures the correct configuration items would be used to generate the
TOE. For example, in a software TOE this may include checking that the
automated production procedures ensure that all source files and related
libraries are included in the compiled object code. Moreover, the procedures
should ensure that compiler options and comparable other options are
defined uniquely. For a hardware TOE, this work unit may include checking
that the automatic production procedures ensure that the belonging parts are
built together and no parts are missing.
1014
The customer can then be confident that the version of the TOE delivered for
installation is derived from the implementation representation in an
unambiguous way and implements the SFRs as described in the ST.
1015
The evaluator should bear in mind that the CM system need not necessarily
possess the capability to produce the TOE, but should provide support for the
process that will help reduce the probability of human error.
ALC_CMC.5.7C
The CM system shall ensure that the person responsible for accepting a
configuration item into CM is not the person who developed it.
ALC_CMC.5-9
The evaluator shall examine the CM system to determine that it ensures that
the person responsible for accepting a configuration item is not the person
who developed it.
1016
The acceptance procedures describe who is responsible for accepting a
configuration item. From these descriptions, the evaluator should be able to
determine that the person who developed a configuration item is in no case
responsible for its acceptance.
ALC_CMC.5.8C
The CM system shall identify the configuration items that comprise the
TSF.
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ALC_CMC.5-10
The evaluator shall examine the CM system to determine that it identifies
the configuration items that comprise the TSF.
1017
The CM documentation should describe how the CM system identifies the
configuration items that comprise the TSF. The evaluator should select a
sample of configuration items covering each type of items, particularly
containing TSF and non-TSF items, and check that they are correctly
classified by the CM system.
1018
For guidance on sampling see A.2, Sampling.
ALC_CMC.5.9C
The CM system shall support the audit of all changes to the TOE by
automated means, including the originator, date, and time in the audit
trail.
ALC_CMC.5-11
The evaluator shall examine the CM system to determine that it supports the
audit of all changes to the TOE by automated means, including the
originator, date, and time in the audit trail.
1019
The evaluator should inspect a sample of audit trails and check, if they
contain the minimum information.
ALC_CMC.5.10C
The CM system shall provide an automated means to identify all other
configuration items that are affected by the change of a given
configuration item.
ALC_CMC.5-12
The evaluator shall examine the CM system to determine that it provides an
automated means to identify all other configuration items that are affected by
the change of a given configuration item.
1020
The CM documentation should describe how the CM system identifies all
other configuration items that are affected by the change of a given
configuration item. The evaluator should select a sample of configuration
items, covering all types of items, and exercise the automated means to
determine that it identifies all items that are affected by the change of the
selected item.
1021
For guidance on sampling see A.2, Sampling.
ALC_CMC.5.11C
The CM system shall be able to identify the version of the implementation
representation from which the TOE is generated.
ALC_CMC.5-13
The evaluator shall examine the CM system to determine that it is able to
identify the version of the implementation representation from which the
TOE is generated.
1022
The CM documentation should describe how the CM system identifies the
version of the implementation representation from which the TOE is
generated. The evaluator should select a sample of the parts used to produce
the TOE and should apply the CM system to verify that it identifies the
corresponding implementation representation in the correct version.
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1023
For guidance on sampling see A.2, Sampling.
ALC_CMC.5.12C
The CM documentation shall include a CM plan.
ALC_CMC.5-14
The evaluator shall check that the CM documentation provided includes a
CM plan. The CM plan needs not to be a connected document, but it is
recommended that there is a single document that describes where the
various parts of the CM plan can be found. If the CM plan is no single
document, the list in the following work unit gives hints regarding which
context is expected.
ALC_CMC.5.13C
The CM plan shall describe how the CM system is used for the
development of the TOE.
ALC_CMC.5-15
The evaluator shall examine the CM plan to determine that it describes how
the CM system is used for the development of the TOE.
1024
The descriptions contained in a CM plan include, if applicable:
a)
all activities performed in the TOE development that are subject to
configuration management procedures (e.g. creation, modification or
deletion of a configuration item, data-backup, archiving);
b)
which means (e.g. CM tools, forms) have to be made available;
c)
the usage of the CM tools: the necessary details for a user of the CM
system to be able to operate the CM tools correctly in order to
maintain the integrity of the TOE;
d)
the production support procedures;
e)
which other objects (development components, tools, assessment
environments, etc) are taken under CM control;
f)
the roles and responsibilities of individuals required to perform
operations on individual configuration items (different roles may be
identified for different types of configuration items (e.g. design
documentation or source code));
g)
how CM instances (e.g. change control boards, interface control
working groups) are introduced and staffed;
h)
the description of the change management;
i)
the procedures that are used to ensure that only authorised individuals
can make changes to configuration items;
j)
the procedures that are used to ensure that concurrency problems do
not occur as a result of simultaneous changes to configuration items;
k)
the evidence that is generated as a result of application of the
procedures. For example, for a change to a configuration item, the
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CM system might record a description of the change, accountability
for the change, identification of all configuration items affected,
status (e.g. pending or completed), and date and time of the change.
This might be recorded in an audit trail of changes made or change
control records;
l)
the approach to version control and unique referencing of TOE
versions (e.g. covering the release of patches in operating systems,
and the subsequent detection of their application).
ALC_CMC.5.14C
The CM plan shall describe the procedures used to accept modified or
newly created configuration items as part of the TOE.
ALC_CMC.5-16
The evaluator shall examine the CM plan to determine that it describes the
procedures used to accept modified or newly created configuration items as
parts of the TOE.
1025
The descriptions of the acceptance procedures in the CM plan should include
the developer roles or individuals responsible for the acceptance and the
criteria to be used for acceptance. They should take into account all
acceptance situations that may occur, in particular:
a)
accepting an item into the CM system for the first time, in particular
inclusion of software, firmware and hardware components from other
manufacturers into the TOE (“integration”);
b)
moving configuration items to the next life-cycle phase at each stage
of the construction of the TOE (e.g. module, subsystem, system);
c)
subsequent to transports between different development sites.
ALC_CMC.5.15C
The evidence shall demonstrate that all configuration items are being
maintained under the CM system.
ALC_CMC.5-17
The evaluator shall check that the configuration items identified in the
configuration list are being maintained by the CM system.
1026
The CM system employed by the developer should maintain the integrity of
the TOE. The evaluator should check that for each type of configuration item
(e.g. design documents or source code modules) contained in the
configuration list there are examples of the evidence generated by the
procedures described in the CM plan. In this case, the approach to sampling
will depend upon the level of granularity used in the CM system to control
CM items. Where, for example, 10,000 source code modules are identified in
the configuration list, a different sampling strategy should be applied
compared to the case in which there are only 5, or even 1. The emphasis of
this activity should be on ensuring that the CM system is being operated
correctly, rather than on the detection of any minor error.
1027
For guidance on sampling see A.2, Sampling.
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ALC_CMC.5.16C
The evidence shall demonstrate that the CM system is being operated in
accordance with the CM plan.
ALC_CMC.5-18
The evaluator shall check the CM documentation to ascertain that it includes
the CM system records identified by the CM plan.
1028
The output produced by the CM system should provide the evidence that the
evaluator needs to be confident that the CM plan is being applied, and also
that all configuration items are being maintained by the CM system as
required by ALC_CMC.5.15C. Example output could include change control
forms, or configuration item access approval forms.
ALC_CMC.5-19
The evaluator shall examine the evidence to determine that the CM system
is being operated in accordance with the CM plan.
1029
The evaluator should select and examine a sample of evidence covering each
type of CM-relevant operation that has been performed on a configuration
item (e.g. creation, modification, deletion, reversion to an earlier version) to
confirm that all operations of the CM system have been carried out in line
with documented procedures. The evaluator confirms that the evidence
includes all the information identified for that operation in the CM plan.
Examination of the evidence may require access to a CM tool that is used.
The evaluator may choose to sample the evidence.
1030
For guidance on sampling see A.2, Sampling.
1031
Further confidence in the correct operation of the CM system and the
effective maintenance of configuration items may be established by means of
interview with selected development staff. In conducting such interviews, the
evaluator should aim to gain a deeper understanding of how the CM system
is used in practise as well as to confirm that the CM procedures are being
applied as described in the CM documentation. Note that such interviews
should complement rather than replace the examination of documentary
evidence, and may not be necessary if the documentary evidence alone
satisfies the requirement. However, given the wide scope of the CM plan it is
possible that some aspects (e.g. roles and responsibilities) may not be clear
from the CM plan and records alone. This is one case where clarification
may be necessary through interviews.
1032
It is expected that the evaluator will visit the development site in support of
this activity.
1033
For guidance on site visits see A.4, Site Visits.
13.2.5.4
Action ALC_CMC.5.2E
ALC_CMC.5-20
The evaluator shall examine the production support procedures to determine
that by following these procedures a TOE would be produced like that one
provided by the developer for testing activities.
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1034
If the TOE is a small software TOE and production consists of compiling
and linking, the evaluator might confirm the adequacy of the production
support procedures by reapplying them himself.
1035
If the production process of the TOE is more complicated (as for example in
the case of a smart card), but has already started, the evaluator should inspect
the application of the production support procedures during a visit of the
development site. He might compare a copy of the TOE produced in his
presence with the samples used for his testing activities.
1036
For guidance on site visits see A.4, Site Visits.
1037
Otherwise the evaluator's determination should be based on the documentary
evidence provided by the developer.
1038
This work unit may be performed in conjunction with the evaluation
activities under Implementation representation (ADV_IMP).
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13.3
CM scope (ALC_CMS)
13.3.1
Evaluation of sub-activity (ALC_CMS.1)
13.3.1.1
Objectives
1039
The objective of this sub-activity is to determine whether the developer
performs configuration management on the TOE and the evaluation
evidence.
13.3.1.2
Input
1040
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the configuration list.
13.3.1.3
Action ALC_CMS.1.1E
ALC_CMS.1.1C
The configuration list shall include the following: the TOE itself; and the
evaluation evidence required by the SARs.
ALC_CMS.1-1
The evaluator shall check that the configuration list includes the following
set of items:
a)
the TOE itself;
b)
the evaluation evidence required by the SARs in the ST.
ALC_CMS.1.2C
The configuration list shall uniquely identify the configuration items.
ALC_CMS.1-2
The evaluator shall examine the configuration list to determine that it
uniquely identifies each configuration item.
1041
The configuration list contains sufficient information to uniquely identify
which version of each item has been used (typically a version number). Use
of this list will enable the evaluator to check that the correct configuration
items, and the correct version of each item, have been used during the
evaluation.
13.3.2
Evaluation of sub-activity (ALC_CMS.2)
13.3.2.1
Objectives
1042
The objective of this sub-activity is to determine whether the configuration
list includes the TOE, the parts that comprise the TOE, and the evaluation
evidence.
13.3.2.2
Input
1043
The evaluation evidence for this sub-activity is:
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a)
the ST;
b)
the configuration list.
13.3.2.3
Action ALC_CMS.2.1E
ALC_CMS.2.1C
The configuration list shall include the following: the TOE itself; the
evaluation evidence required by the SARs; and the parts that comprise the
TOE.
ALC_CMS.2-1
The evaluator shall check that the configuration item list includes the set of
items required by the CC.
1044
The list includes at least the following:
a)
the TOE itself;
b)
the parts that comprise the TOE;
c)
the evaluation evidence required by the SARs.
ALC_CMS.2.2C
The configuration list shall uniquely identify the configuration items.
ALC_CMS.2-2
The evaluator shall examine the configuration list to determine that it
uniquely identifies each configuration item.
1045
The configuration list contains sufficient information to uniquely identify
which version of each item has been used (typically a version number). Use
of this list will enable the evaluator to check that the correct configuration
items, and the correct version of each item, have been used during the
evaluation.
ALC_CMS.2.3C
For each TSF relevant configuration item, the configuration list shall
indicate the developer of the item.
ALC_CMS.2-3
The evaluator shall check that the configuration list indicates the developer
of each TSF relevant configuration item.
1046
If only one developer is involved in the development of the TOE, this work
unit is not applicable, and is therefore considered to be satisfied.
13.3.3
Evaluation of sub-activity (ALC_CMS.3)
13.3.3.1
Objectives
1047
The objective of this sub-activity is to determine whether the configuration
list includes the TOE, the parts that comprise the TOE, the TOE
implementation representation, and the evaluation evidence.
13.3.3.2
Input
1048
The evaluation evidence for this sub-activity is:
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a)
the ST;
b)
the configuration list.
13.3.3.3
Action ALC_CMS.3.1E
ALC_CMS.3.1C
The configuration list shall include the following: the TOE itself; the
evaluation evidence required by the SARs; the parts that comprise the
TOE; and the implementation representation.
ALC_CMS.3-1
The evaluator shall check that the configuration list includes the following
set of items:
a)
the TOE itself;
b)
the parts that comprise the TOE;
c)
the TOE implementation representation;
d)
the evaluation evidence required by the SARs in the ST.
ALC_CMS.3.2C
The configuration list shall uniquely identify the configuration items.
ALC_CMS.3-2
The evaluator shall examine the configuration list to determine that it
uniquely identifies each configuration item.
1049
The configuration list contains sufficient information to uniquely identify
which version of each item has been used (typically a version number). Use
of this list will enable the evaluator to check that the correct configuration
items, and the correct version of each item, have been used during the
evaluation.
ALC_CMS.3.3C
For each TSF relevant configuration item, the configuration list shall
indicate the developer of the item.
ALC_CMS.3-3
The evaluator shall check that the configuration list indicates the developer
of each TSF relevant configuration item.
1050
If only one developer is involved in the development of the TOE, this work
unit is not applicable, and is therefore considered to be satisfied.
13.3.4
Evaluation of sub-activity (ALC_CMS.4)
13.3.4.1
Objectives
1051
The objective of this sub-activity is to determine whether the configuration
list includes the TOE, the parts that comprise the TOE, the TOE
implementation representation, security flaws, and the evaluation evidence.
13.3.4.2
Input
1052
The evaluation evidence for this sub-activity is:
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a)
the ST;
b)
the configuration list.
13.3.4.3
Action ALC_CMS.4.1E
ALC_CMS.4.1C
The configuration list shall include the following: the TOE itself; the
evaluation evidence required by the SARs; the parts that comprise the
TOE; the implementation representation; and security flaw reports and
resolution status.
ALC_CMS.4-1
The evaluator shall check that the configuration list includes the following
set of items:
a)
the TOE itself;
b)
the parts that comprise the TOE;
c)
the TOE implementation representation;
d)
the evaluation evidence required by the SARs in the ST;
e)
the documentation used to record details of reported security flaws
associated with the implementation (e.g., problem status reports
derived from a developer's problem database).
ALC_CMS.4.2C
The configuration list shall uniquely identify the configuration items.
ALC_CMS.4-2
The evaluator shall examine the configuration list to determine that it
uniquely identifies each configuration item.
1053
The configuration list contains sufficient information to uniquely identify
which version of each item has been used (typically a version number). Use
of this list will enable the evaluator to check that the correct configuration
items, and the correct version of each item, have been used during the
evaluation.
ALC_CMS.4.3C
For each TSF relevant configuration item, the configuration list shall
indicate the developer of the item.
ALC_CMS.4-3
The evaluator shall check that the configuration list indicates the developer
of each TSF relevant configuration item.
1054
If only one developer is involved in the development of the TOE, this work
unit is not applicable, and is therefore considered to be satisfied.
13.3.5
Evaluation of sub-activity (ALC_CMS.5)
13.3.5.1
Objectives
1055
The objective of this sub-activity is to determine whether the configuration
list includes the TOE, the parts that comprise the TOE, the TOE
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implementation representation, security flaws, development tools and related
information, and the evaluation evidence.
13.3.5.2
Input
1056
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the configuration list.
13.3.5.3
Action ALC_CMS.5.1E
ALC_CMS.5.1C
The configuration list shall include the following: the TOE itself; the
evaluation evidence required by the SARs; the parts that comprise the
TOE; the implementation representation; security flaw reports and
resolution status; and development tools and related information.
ALC_CMS.5-1
The evaluator shall check that the configuration list includes the following
set of items:
a)
the TOE itself;
b)
the parts that comprise the TOE;
c)
the TOE implementation representation;
d)
the evaluation evidence required by the SARs in the ST;
e)
the documentation used to record details of reported security flaws
associated with the implementation (e.g., problem status reports
derived from a developer's problem database);
f)
all tools (incl. test software, if applicable) involved in the
development and production of the TOE including the names,
versions, configurations and roles of each development tool, and
related documentation. E.g. for a software TOE: “development tools”
are usually programming languages and compiler and “related
documentation” comprises compiler and linker options. For a
hardware TOE, “development tools” might be hardware design
languages, simulation and synthesis tools, compilers, and “related
documentation” might comprise compiler options again.
ALC_CMS.5.2C
The configuration list shall uniquely identify the configuration items.
ALC_CMS.5-2
The evaluator shall examine the configuration list to determine that it
uniquely identifies each configuration item.
1057
The configuration list contains sufficient information to uniquely identify
which version of each item has been used (typically a version number). Use
of this list will enable the evaluator to check that the correct configuration
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items, and the correct version of each item, have been used during the
evaluation.
ALC_CMS.5.3C
For each TSF relevant configuration item, the configuration list shall
indicate the developer of the item.
ALC_CMS.5-3
The evaluator shall check that the configuration list indicates the developer
of each TSF relevant configuration item.
1058
If only one developer is involved in the development of the TOE, this work
unit is not applicable, and is therefore considered to be satisfied.
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13.4
Delivery (ALC_DEL)
13.4.1
Evaluation of sub-activity (ALC_DEL.1)
13.4.1.1
Objectives
1059
The objective of this sub-activity is to determine whether the delivery
documentation describes all procedures used to maintain security of the TOE
when distributing the TOE to the user.
13.4.1.2
Input
1060
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the delivery documentation.
13.4.1.3
Action ALC_DEL.1.1E
ALC_DEL.1.1C
The delivery documentation shall describe all procedures that are
necessary to maintain security when distributing versions of the TOE to
the consumer.
ALC_DEL.1-1
The evaluator shall examine the delivery documentation to determine that it
describes all procedures that are necessary to maintain security when
distributing versions of the TOE or parts of it to the consumer.
1061
The delivery documentation describes proper procedures to maintain security
of the TOE during transfer of the TOE or its component parts and to
determine the identification of the TOE.
1062
The delivery documentation should cover the entire TOE, but may contain
different procedures for different parts of the TOE. The evaluation should
consider the totality of procedures.
1063
The delivery procedures should be applicable across all phases of delivery
from the production environment to the installation environment (e.g.
packaging, storage and distribution). Standard commercial practise for
packaging and delivery may be acceptable. This includes shrink wrapped
packaging, a security tape or a sealed envelope. For the distribution, physical
(e.g. public mail or a private distribution service) or electronic (e.g.
electronic mail or downloading off the Internet) procedures may be used.
1064
Cryptographic checksums or a software signature may be used by the
developer to ensure that tampering or masquerading can be detected. Tamper
proof seals additionally indicate if the confidentiality has been broken. For
software TOEs, confidentiality might be assured by using encryption. If
availability is of concern, a secure transportation might be required.
1065
Interpretation of the term “necessary to maintain security” will need to
consider:
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−
The nature of the TOE (e.g. whether it is software or hardware).
−
The overall security level stated for the TOE by the chosen level of
the Vulnerability Assessment. If the TOE is required to be resistant
against attackers of a certain potential in its intended environment,
this should also apply to the delivery of the TOE. The evaluator
should determine that a balanced approach has been taken, such that
delivery does not present a weak point in an otherwise secure
development process.
−
The security objectives provided by the ST. In particular, the security
aspects (integrity, confidentiality, availability) relevant for the actual
TOE should be derived from the security objectives for the
development environment defined in the ST. The emphasis in the
delivery documentation is likely to be on measures related to
integrity, as integrity of the TOE is always important. However,
confidentiality and availability of the delivery will be of concern in
the delivery of some TOEs; procedures relating to these aspects of the
secure delivery should also be discussed in the procedures.
13.4.1.4
Implied evaluator action
ALC_DEL.1.2D
The developer shall use the delivery procedures.
ALC_DEL.1-2
The evaluator shall examine aspects of the delivery process to determine that
the delivery procedures are used.
1066
The approach taken by the evaluator to check the application of delivery
procedures will depend on the nature of the TOE, and the delivery process
itself. In addition to examination of the procedures themselves, the evaluator
seeks some assurance that they are applied in practise. Some possible
approaches are:
a)
a visit to the distribution site(s) where practical application of the
procedures may be observed;
b)
examination of the TOE at some stage during delivery, or after the
user has received it (e.g. checking for tamper proof seals);
c)
observing that the process is applied in practise when the evaluator
obtains the TOE through regular channels;
d)
questioning end users as to how the TOE was delivered.
1067
For guidance on site visits see A.4, Site Visits.
1068
It may be the case of a newly developed TOE that the delivery procedures
have yet to be exercised. In these cases, the evaluator has to be satisfied that
appropriate procedures and facilities are in place for future deliveries and
that all personnel involved are aware of their responsibilities. The evaluator
may request a “dry run” of a delivery if this is practical. If the developer has
produced other similar products, then an examination of procedures in their
use may be useful in providing assurance.
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13.5
Development security (ALC_DVS)
13.5.1
Evaluation of sub-activity (ALC_DVS.1)
13.5.1.1
Objectives
1069
The objective of this sub-activity is to determine whether the developer's
security controls on the development environment are adequate to provide
the confidentiality and integrity of the TOE design and implementation that
is necessary to ensure that secure operation of the TOE is not compromised.
13.5.1.2
Input
1070
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the development security documentation.
1071
In addition, the evaluator may need to examine other deliverables to
determine that the security controls are well-defined and followed.
Specifically, the evaluator may need to examine the developer's
configuration management documentation (the input for the Evaluation of
sub-activity (ALC_CMC.4) “Production support and acceptance procedures”
and the Evaluation of sub-activity (ALC_CMS.4) “Problem tracking CM
coverage”). Evidence that the procedures are being applied is also required.
13.5.1.3
Action ALC_DVS.1.1E
ALC_DVS.1.1C
The development security documentation shall describe all the physical,
procedural, personnel, and other security measures that are necessary to
protect the confidentiality and integrity of the TOE design and
implementation in its development environment.
ALC_DVS.1-1
The evaluator shall examine the development security documentation to
determine that it details all security measures used in the development
environment that are necessary to protect the confidentiality and integrity of
the TOE design and implementation.
1072
The evaluator determines what is necessary by first referring to the ST for
any information that may assist in the determination of necessary protection,
especially the security objectives for the development environment.
1073
If no explicit information is available from the ST the evaluator will need to
make a determination of the necessary measures. In cases where the
developer's measures are considered less than what is necessary, a clear
justification should be provided for the assessment, based on a potential
exploitable vulnerability.
1074
The following types of security measures are considered by the evaluator
when examining the documentation:
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a)
physical, for example physical access controls used to prevent
unauthorised access to the TOE development environment (during
normal working hours and at other times);
b)
procedural, for example covering:
−
granting of access to the development environment or to
specific parts of the environment such as development
machines
−
revocation of access rights when a person leaves the
development team
−
transfer of protected material within and out of the
development environment and between different development
sites in accordance with defined acceptance procedures
−
admitting and escorting visitors to the development
environment
−
roles and responsibilities in ensuring the continued
application of security measures, and the detection of security
breaches.
c)
personnel, for example any controls or checks made to establish the
trustworthiness of new development staff;
d)
other security measures, for example the logical protections on any
development machines.
1075
The development security documentation should identify the locations at
which development occurs, and describe the aspects of development
performed, along with the security measures applied at each location and for
transports between different locations. For example, development could
occur at multiple facilities within a single building, multiple buildings at the
same site, or at multiple sites. Transports of parts of the TOE or the
unfinished TOE between different development sites are to be covered by
Development security (ALC_DVS), whereas the transport of the finished
TOE to the consumer is dealt with in Delivery (ALC_DEL).
1076
Development includes the production of the TOE.
ALC_DVS.1-2
The evaluator shall examine the development confidentiality and integrity
policies in order to determine the sufficiency of the security measures
employed.
1077
These include the policies governing:
a)
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confidential, and which members of the development staff are
allowed to access such material;
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b)
what material must be protected from unauthorised modification in
order to preserve the integrity of the TOE, and which members of the
development staff are allowed to modify such material.
1078
The evaluator should determine that these policies are described in the
development security documentation, that the security measures employed
are consistent with the policies, and that they are complete.
1079
It should be noted that configuration management procedures will help
protect the integrity of the TOE and the evaluator should avoid overlap with
the work-units conducted for the CM capabilities (ALC_CMC). For
example, the CM documentation may describe the security procedures
necessary for controlling the roles or individuals who should have access to
the development environment and who may modify the TOE.
1080
Whereas the CM capabilities (ALC_CMC) requirements are fixed, those for
the Development security (ALC_DVS), mandating only necessary measures,
are dependent on the nature of the TOE, and on information that may be
provided in the ST. For example, the ST may identify a security objective for
the development environment that requires the TOE to be developed by staff
that has security clearance. The evaluators would then determine that such a
policy had been applied under this sub-activity.
13.5.1.4
Action ALC_DVS.1.2E
ALC_DVS.1-3
The evaluator shall examine the development security documentation and
associated evidence to determine that the security measures are being
applied.
1081
This work unit requires the evaluator to determine that the security measures
described in the development security documentation are being followed,
such that the integrity of the TOE and the confidentiality of associated
documentation is being adequately protected. For example, this could be
determined by examination of the documentary evidence provided.
Documentary evidence should be supplemented by visiting the development
environment. A visit to the development environment will allow the
evaluator to:
a)
observe the application of security measures (e.g. physical measures);
b)
examine documentary evidence of application of procedures;
c)
interview development staff to check awareness of the development
security policies and procedures, and their responsibilities.
1082
A development site visit is a useful means of gaining confidence in the
measures being used. Any decision not to make such a visit should be
determined in consultation with the evaluation authority.
1083
For guidance on site visits see A.4, Site Visits.
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13.5.2
Evaluation of sub-activity (ALC_DVS.2)
13.5.2.1
Objectives
1084
The objective of this sub-activity is to determine whether the developer's
security controls on the development environment are adequate to provide
the confidentiality and integrity of the TOE design and implementation that
is necessary to ensure that secure operation of the TOE is not compromised.
Additionally, sufficiency of the measures as applied is intended be justified.
13.5.2.2
Input
1085
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the development security documentation.
1086
In addition, the evaluator may need to examine other deliverables to
determine that the security controls are well-defined and followed.
Specifically, the evaluator may need to examine the developer's
configuration management documentation (the input for the Evaluation of
sub-activity (ALC_CMC.4) “Production support and acceptance procedures”
and the Evaluation of sub-activity (ALC_CMS.4) “Problem tracking CM
coverage”). Evidence that the procedures are being applied is also required.
13.5.2.3
Action ALC_DVS.2.1E
ALC_DVS.2.1C
The development security documentation shall describe all the physical,
procedural, personnel, and other security measures that are necessary to
protect the confidentiality and integrity of the TOE design and
implementation in its development environment.
ALC_DVS.2-1
The evaluator shall examine the development security documentation to
determine that it details all security measures used in the development
environment that are necessary to protect the confidentiality and integrity of
the TOE design and implementation.
1087
The evaluator determines what is necessary by first referring to the ST for
any information that may assist in the determination of necessary protection,
especially the security objectives for the development environment.
1088
If no explicit information is available from the ST the evaluator will need to
make a determination of the necessary measures. In cases where the
developer's measures are considered less than what is necessary, a clear
justification should be provided for the assessment, based on a potential
exploitable vulnerability.
1089
The following types of security measures are considered by the evaluator
when examining the documentation:
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a)
physical, for example physical access controls used to prevent
unauthorised access to the TOE development environment (during
normal working hours and at other times);
b)
procedural, for example covering:
−
granting of access to the development environment or to
specific parts of the environment such as development
machines
−
revocation of access rights when a person leaves the
development team
−
transfer of protected material out of the development
environment and between different development sites in
accordance with defined acceptance procedures
−
admitting and escorting visitors to the development
environment
−
roles and responsibilities in ensuring the continued
application of security measures, and the detection of security
breaches.
c)
personnel, for example any controls or checks made to establish the
trustworthiness of new development staff;
d)
other security measures, for example the logical protections on any
development machines.
1090
The development security documentation should identify the locations at
which development occurs, and describe the aspects of development
performed, along with the security measures applied at each location and for
transports between different locations. For example, development could
occur at multiple facilities within a single building, multiple buildings at the
same site, or at multiple sites. Transports of parts of the TOE or the
unfinished TOE between different development sites are to be covered by the
Development security (ALC_DVS), whereas the transport of the finished
TOE to the consumer is dealt with in the Delivery (ALC_DEL).
1091
Development includes the production of the TOE.
ALC_DVS.2.2C
The development security documentation shall justify that the security
measures provide the necessary level of protection to maintain the
confidentiality and integrity of the TOE.
ALC_DVS.2-2
The evaluator shall examine the development security documentation to
determine that an appropriate justification is given why the security measures
provide the necessary level of protection to maintain the confidentiality and
integrity of the TOE.
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1092
Since attacks on the TOE or its related information are assumed in different
design and production stages, measures and procedures need to have an
appropriate level necessary to prevent those attacks or to make them more
difficult.
1093
Since this level depends on the overall attack potential claimed for the TOE
(cf. the Vulnerability analysis (AVA_VAN) component chosen), the
development security documentation should justify the necessary level of
protection to maintain the confidentiality and integrity of the TOE. This level
has to be achieved by the security measures applied.
1094
The concept of protection measures should be consistent, and the
justification should include an analysis of how the measures are mutually
supportive. All aspects of development and production on all the different
sites with all roles involved up to delivery of the TOE should be analysed.
1095
Justification may include an analysis of potential vulnerabilities taking the
applied security measures into account.
1096
There may be a convincing argument showing that e.g.
−
The technical measures and mechanisms of the developer's
infrastructure are sufficient for keeping the appropriate security level
(e.g. cryptographic mechanisms as well as physical protection
mechanisms, properties of the CM system (cf. ALC_CMC.4-5));
−
The system containing the implementation representation of the TOE
(including concerning guidance documents) provides effective
protection against logical attacks e.g. by “Trojan” code or viruses. It
might be adequate, if the implementation representation is kept on an
isolated system where only the software necessary to maintain it is
installed and where no additional software is installed afterwards.
−
Data brought into this system should be carefully considered to
prevent the installation of hidden functionality onto the system. The
effectiveness of these measures should be tested, e.g. by
independently trying to get access to the machine, install some
additional executable (program, macro etc.) or get some information
out of the machine using logical attacks.
−
The appropriate organisational (procedural and personal) measures
are unconditionally enforced.
ALC_DVS.2-3
The evaluator shall examine the development confidentiality and integrity
policies in order to determine the sufficiency of the security measures
employed.
1097
These include the policies governing:
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a)
what information relating to the TOE development needs to be kept
confidential, and which members of the development staff are
allowed to access such material;
b)
what material must be protected from unauthorised modification in
order to preserve the integrity of the TOE, and which members of the
development staff are allowed to modify such material.
1098
The evaluator should determine that these policies are described in the
development security documentation, that the security measures employed
are consistent with the policies, and that they are complete.
1099
It should be noted that configuration management procedures will help
protect the integrity of the TOE and the evaluator should avoid overlap with
the work-units conducted for the CM capabilities (ALC_CMC). For
example, the CM documentation may describe the security procedures
necessary for controlling the roles or individuals who should have access to
the development environment and who may modify the TOE.
1100
Whereas the CM capabilities (ALC_CMC) requirements are fixed, those for
the Development security (ALC_DVS), mandating only necessary measures,
are dependent on the nature of the TOE, and on information that may be
provided in the ST. For example, the ST may identify a security objective for
the development environment that requires the TOE to be developed by staff
that has security clearance. The evaluators would then determine that such a
policy had been applied under this sub-activity.
13.5.2.4
Action ALC_DVS.2.2E
ALC_DVS.2-4
The evaluator shall examine the development security documentation and
associated evidence to determine that the security measures are being
applied.
1101
This work unit requires the evaluator to determine that the security measures
described in the development security documentation are being followed,
such that the integrity of the TOE and the confidentiality of associated
documentation is being adequately protected. For example, this could be
determined by examination of the documentary evidence provided.
Documentary evidence should be supplemented by visiting the development
environment. A visit to the development environment will allow the
evaluator to:
a)
observe the application of security measures (e.g. physical measures);
b)
examine documentary evidence of application of procedures;
c)
interview development staff to check awareness of the development
security policies and procedures, and their responsibilities.
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1102
A development site visit is a useful means of gaining confidence in the
measures being used. Any decision not to make such a visit should be
determined in consultation with the evaluation authority.
1103
For guidance on site visits see A.4, Site Visits.
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13.6
Flaw remediation (ALC_FLR)
13.6.1
Evaluation of sub-activity (ALC_FLR.1)
13.6.1.1
Objectives
1104
The objective of this sub-activity is to determine whether the developer has
established flaw remediation procedures that describe the tracking of security
flaws, the identification of corrective actions, and the distribution of
corrective action information to TOE users.
13.6.1.2
Input
1105
The evaluation evidence for this sub-activity is:
a)
the flaw remediation procedures documentation.
13.6.1.3
Action ALC_FLR.1.1E
ALC_FLR.1.1C
The flaw remediation procedures documentation shall describe the
procedures used to track all reported security flaws in each release of the
TOE.
ALC_FLR.1-1
The evaluator shall examine the flaw remediation procedures documentation
to determine that it describes the procedures used to track all reported
security flaws in each release of the TOE.
1106
The procedures describe the actions that are taken by the developer from the
time each suspected security flaw is reported to the time that it is resolved.
This includes the flaw's entire time frame, from initial detection through
ascertaining that the flaw is a security flaw, to resolution of the security flaw.
1107
If a flaw is discovered not to be security-relevant, there is no need (for the
purposes of the Flaw remediation (ALC_FLR) requirements) for the flaw
remediation procedures to track it further; only that there be an explanation
of why the flaw is not security-relevant.
1108
While these requirements do not mandate that there be a publicised means
for TOE users to report security flaws, they do mandate that all security
flaws that are reported be tracked. That is, a reported security flaw cannot be
ignored simply because it comes from outside the developer's organisation.
ALC_FLR.1.2C
The flaw remediation procedures shall require that a description of the
nature and effect of each security flaw be provided, as well as the status of
finding a correction to that flaw.
ALC_FLR.1-2
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would produce a description of each
security flaw in terms of its nature and effects.
1109
The procedures identify the actions that are taken by the developer to
describe the nature and effects of each security flaw in sufficient detail to be
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able to reproduce it. The description of the nature of a security flaw
addresses whether it is an error in the documentation, a flaw in the design of
the TSF, a flaw in the implementation of the TSF, etc. The description of the
security flaw's effects identifies the portions of the TSF that are affected and
how those portions are affected. For example, a security flaw in the
implementation might be found that affects the identification and
authentication enforced by the TSF by permitting authentication with the
password “BACK DOOR”.
ALC_FLR.1-3
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would identify the status of finding a
correction to each security flaw.
1110
The flaw remediation procedures identify the different stages of security
flaws. This differentiation includes at least: suspected security flaws that
have been reported, suspected security flaws that have been confirmed to be
security flaws, and security flaws whose solutions have been implemented. It
is permissible that additional stages (e.g. flaws that have been reported but
not yet investigated, flaws that are under investigation, security flaws for
which a solution has been found but not yet implemented) be included.
ALC_FLR.1.3C
The flaw remediation procedures shall require that corrective actions be
identified for each of the security flaws.
ALC_FLR.1-4
The evaluator shall check the flaw remediation procedures to determine that
the application of these procedures would identify the corrective action for
each security flaw.
1111
Corrective action may consist of a repair to the hardware, firmware, or
software portions of the TOE, a modification of TOE guidance, or both.
Corrective action that constitutes modifications to TOE guidance (e.g. details
of procedural measures to be taken to obviate the security flaw) includes
both those measures serving as only an interim solution (until the repair is
issued) as well as those serving as a permanent solution (where it is
determined that the procedural measure is the best solution).
1112
If the source of the security flaw is a documentation error, the corrective
action consists of an update of the affected TOE guidance. If the corrective
action is a procedural measure, this measure will include an update made to
the affected TOE guidance to reflect these corrective procedures.
ALC_FLR.1.4C
The flaw remediation procedures documentation shall describe the
methods used to provide flaw information, corrections and guidance on
corrective actions to TOE users.
ALC_FLR.1-5
The evaluator shall examine the flaw remediation procedures documentation
to determine that it describes a means of providing the TOE users with the
necessary information on each security flaw.
1113
The necessary information about each security flaw consists of its
description (not necessarily at the same level of detail as that provided as part
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of work unit ALC_FLR.1-2), the prescribed corrective action, and any
associated guidance on implementing the correction.
1114
TOE users may be provided with such information, correction, and
documentation updates in any of several ways, such as their posting to a
website, their being sent to TOE users, or arrangements made for the
developer to install the correction. In cases where the means of providing this
information requires action to be initiated by the TOE user, the evaluator
examines any TOE guidance to ensure that it contains instructions for
retrieving the information.
1115
The only metric for assessing the adequacy of the method used for providing
the information, corrections and guidance is that there be a reasonable
expectation that TOE users can obtain or receive it. For example, consider
the method of dissemination where the requisite data is posted to a website
for one month, and the TOE users know that this will happen and when this
will happen. This may not be especially reasonable or effective (as, say, a
permanent posting to the website), yet it is feasible that the TOE user could
obtain the necessary information. On the other hand, if the information were
posted to the website for only one hour, yet TOE users had no way of
knowing this or when it would be posted, it is infeasible that they would ever
get the necessary information.
13.6.2
Evaluation of sub-activity (ALC_FLR.2)
13.6.2.1
Objectives
1116
The objective of this sub-activity is to determine whether the developer has
established flaw remediation procedures that describe the tracking of security
flaws, the identification of corrective actions, and the distribution of
corrective action information to TOE users. Additionally, this sub-activity
determines whether the developer's procedures provide for the corrections of
security flaws, for the receipt of flaw reports from TOE users, and for
assurance that the corrections introduce no new security flaws.
1117
In order for the developer to be able to act appropriately upon security flaw
reports from TOE users, TOE users need to understand how to submit
security flaw reports to the developer, and developers need to know how to
receive these reports. Flaw remediation guidance addressed to the TOE user
ensures that TOE users are aware of how to communicate with the
developer; flaw remediation procedures describe the developer's role is such
communication
13.6.2.2
Input
1118
The evaluation evidence for this sub-activity is:
a)
the flaw remediation procedures documentation;
b)
flaw remediation guidance documentation.
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13.6.2.3
Action ALC_FLR.2.1E
ALC_FLR.2.1C
The flaw remediation procedures documentation shall describe the
procedures used to track all reported security flaws in each release of the
TOE.
ALC_FLR.2-1
The evaluator shall examine the flaw remediation procedures documentation
to determine that it describes the procedures used to track all reported
security flaws in each release of the TOE.
1119
The procedures describe the actions that are taken by the developer from the
time each suspected security flaw is reported to the time that it is resolved.
This includes the flaw's entire time frame, from initial detection through
ascertaining that the flaw is a security flaw, to resolution of the security flaw.
1120
If a flaw is discovered not to be security-relevant, there is no need (for the
purposes of the Flaw remediation (ALC_FLR) requirements) for the flaw
remediation procedures to track it further; only that there be an explanation
of why the flaw is not security-relevant.
ALC_FLR.2.2C
The flaw remediation procedures shall require that a description of the
nature and effect of each security flaw be provided, as well as the status of
finding a correction to that flaw.
ALC_FLR.2-2
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would produce a description of each
security flaw in terms of its nature and effects.
1121
The procedures identify the actions that are taken by the developer to
describe the nature and effects of each security flaw in sufficient detail to be
able to reproduce it. The description of the nature of a security flaw
addresses whether it is an error in the documentation, a flaw in the design of
the TSF, a flaw in the implementation of the TSF, etc. The description of the
security flaw's effects identifies the portions of the TSF that are affected and
how those portions are affected. For example, a security flaw in the
implementation might be found that affects the identification and
authentication enforced by the TSF by permitting authentication with the
password “BACKDOOR”.
ALC_FLR.2-3
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would identify the status of finding a
correction to each security flaw.
1122
The flaw remediation procedures identify the different stages of security
flaws. This differentiation includes at least: suspected security flaws that
have been reported, suspected security flaws that have been confirmed to be
security flaws, and security flaws whose solutions have been implemented. It
is permissible that additional stages (e.g. flaws that have been reported but
not yet investigated, flaws that are under investigation, security flaws for
which a solution has been found but not yet implemented) be included.
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ALC_FLR.2.3C
The flaw remediation procedures shall require that corrective actions be
identified for each of the security flaws.
ALC_FLR.2-4
The evaluator shall check the flaw remediation procedures to determine that
the application of these procedures would identify the corrective action for
each security flaw.
1123
Corrective action may consist of a repair to the hardware, firmware, or
software portions of the TOE, a modification of TOE guidance, or both.
Corrective action that constitutes modifications to TOE guidance (e.g. details
of procedural measures to be taken to obviate the security flaw) includes
both those measures serving as only an interim solution (until the repair is
issued) as well as those serving as a permanent solution (where it is
determined that the procedural measure is the best solution).
1124
If the source of the security flaw is a documentation error, the corrective
action consists of an update of the affected TOE guidance. If the corrective
action is a procedural measure, this measure will include an update made to
the affected TOE guidance to reflect these corrective procedures.
ALC_FLR.2.4C
The flaw remediation procedures documentation shall describe the
methods used to provide flaw information, corrections and guidance on
corrective actions to TOE users.
ALC_FLR.2-5
The evaluator shall examine the flaw remediation procedures documentation
to determine that it describes a means of providing the TOE users with the
necessary information on each security flaw.
1125
The necessary information about each security flaw consists of its
description (not necessarily at the same level of detail as that provided as part
of work unit ALC_FLR.2-2), the prescribed corrective action, and any
associated guidance on implementing the correction.
1126
TOE users may be provided with such information, correction, and
documentation updates in any of several ways, such as their posting to a
website, their being sent to TOE users, or arrangements made for the
developer to install the correction. In cases where the means of providing this
information requires action to be initiated by the TOE user, the evaluator
examines any TOE guidance to ensure that it contains instructions for
retrieving the information.
1127
The only metric for assessing the adequacy of the method used for providing
the information, corrections and guidance is that there be a reasonable
expectation that TOE users can obtain or receive it. For example, consider
the method of dissemination where the requisite data is posted to a website
for one month, and the TOE users know that this will happen and when this
will happen. This may not be especially reasonable or effective (as, say, a
permanent posting to the website), yet it is feasible that the TOE user could
obtain the necessary information. On the other hand, if the information were
posted to the website for only one hour, yet TOE users had no way of
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knowing this or when it would be posted, it is infeasible that they would ever
get the necessary information.
ALC_FLR.2.5C
The flaw remediation procedures shall describe a means by which the
developer receives from TOE users reports and enquiries of suspected
security flaws in the TOE.
ALC_FLR.2-6
The evaluator shall examine the flaw remediation procedures to determine
that they describe procedures for the developer to accept reports of security
flaws or requests for corrections to such flaws.
1128
The procedures ensure that TOE users have a means by which they can
communicate with the TOE developer. By having a means of contact with
the developer, the user can report security flaws, enquire about the status of
security flaws, or request corrections to flaws. This means of contact may be
part of a more general contact facility for reporting non-security related
problems.
1129
The use of these procedures is not restricted to TOE users; however, only the
TOE users are actively supplied with the details of these procedures. Others
who might have access to or familiarity with the TOE can use the same
procedures to submit reports to the developer, who is then expected to
process them. Any means of submitting reports to the developer, other than
those identified by the developer, are beyond the scope of this work unit;
reports generated by other means need not be addressed.
ALC_FLR.2.6C
The procedures for processing reported security flaws shall ensure that any
reported flaws are remediated and the remediation procedures issued to
TOE users.
ALC_FLR.2-7
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would help to ensure every reported
flaw is corrected.
1130
The flaw remediation procedures cover not only those security flaws
discovered and reported by developer personnel, but also those reported by
TOE users. The procedures are sufficiently detailed so that they describe
how it is ensured that each reported security flaw is corrected. The
procedures contain reasonable steps that show progress leading to the
eventual, inevitable resolution.
1131
The procedures describe the process that is taken from the point at which the
suspected security flaw is determined to be a security flaw to the point at
which it is resolved.
ALC_FLR.2-8
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would help to ensure that the TOE
users are issued remediation procedures for each security flaw.
1132
The procedures describe the process that is taken from the point at which a
security flaw is resolved to the point at which the remediation procedures are
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provided. The procedures for delivering corrective actions should be
consistent with the security objectives; they need not necessarily be identical
to the procedures used for delivering the TOE, as documented to meet
ALC_DEL, if included in the assurance requirements. For example, if the
hardware portion of a TOE were originally delivered by bonded courier,
updates to hardware resulting from flaw remediation would likewise be
expected to be distributed by bonded courier. Updates unrelated to flaw
remediation would follow the procedures set forth in the documentation
meeting the Delivery (ALC_DEL) requirements.
ALC_FLR.2.7C
The procedures for processing reported security flaws shall provide
safeguards that any corrections to these security flaws do not introduce
any new flaws.
ALC_FLR.2-9
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would result in safeguards that the
potential correction contains no adverse effects.
1133
Through analysis, testing, or a combination of the two, the developer may
reduce the likelihood that adverse effects will be introduced when a security
flaw is corrected. The evaluator assesses whether the procedures provide
detail in how the necessary mix of analysis and testing actions is to be
determined for a given correction.
1134
The evaluator also determines that, for instances where the source of the
security flaw is a documentation problem, the procedures include the means
of safeguarding against the introduction of contradictions with other
documentation.
ALC_FLR.2.8C
The flaw remediation guidance shall describe a means by which TOE
users report to the developer any suspected security flaws in the TOE.
ALC_FLR.2-10
The evaluator shall examine the flaw remediation guidance to determine that
the application of these procedures would result in a means for the TOE user
to provide reports of suspected security flaws or requests for corrections to
such flaws.
1135
The guidance ensures that TOE users have a means by which they can
communicate with the TOE developer. By having a means of contact with
the developer, the user can report security flaws, enquire about the status of
security flaws, or request corrections to flaws.
13.6.3
Evaluation of sub-activity (ALC_FLR.3)
13.6.3.1
Objectives
1136
The objective of this sub-activity is to determine whether the developer has
established flaw remediation procedures that describe the tracking of security
flaws, the identification of corrective actions, and the distribution of
corrective action information to TOE users. Additionally, this sub-activity
determines whether the developer's procedures provide for the corrections of
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security flaws, for the receipt of flaw reports from TOE users, for assurance
that the corrections introduce no new security flaws, for the establishment of
a point of contact for each TOE user, and for the timely issue of corrective
actions to TOE users.
1137
In order for the developer to be able to act appropriately upon security flaw
reports from TOE users, TOE users need to understand how to submit
security flaw reports to the developer, and developers need to know how to
receive these reports. Flaw remediation guidance addressed to the TOE user
ensures that TOE users are aware of how to communicate with the
developer; flaw remediation procedures describe the developer's role is such
communication.
13.6.3.2
Input
1138
The evaluation evidence for this sub-activity is:
a)
the flaw remediation procedures documentation;
b)
flaw remediation guidance documentation.
13.6.3.3
Action ALC_FLR.3.1E
ALC_FLR.3.1C
The flaw remediation procedures documentation shall describe the
procedures used to track all reported security flaws in each release of the
TOE.
ALC_FLR.3-1
The evaluator shall examine the flaw remediation procedures documentation
to determine that it describes the procedures used to track all reported
security flaws in each release of the TOE.
1139
The procedures describe the actions that are taken by the developer from the
time each suspected security flaw is reported to the time that it is resolved.
This includes the flaw's entire time frame, from initial detection through
ascertaining that the flaw is a security flaw, to resolution of the security flaw.
1140
If a flaw is discovered not to be security-relevant, there is no need (for the
purposes of the Flaw remediation (ALC_FLR) requirements) for the flaw
remediation procedures to track it further; only that there be an explanation
of why the flaw is not security-relevant.
ALC_FLR.3.2C
The flaw remediation procedures shall require that a description of the
nature and effect of each security flaw be provided, as well as the status of
finding a correction to that flaw.
ALC_FLR.3-2
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would produce a description of each
security flaw in terms of its nature and effects.
1141
The procedures identify the actions that are taken by the developer to
describe the nature and effects of each security flaw in sufficient detail to be
able to reproduce it. The description of the nature of a security flaw
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addresses whether it is an error in the documentation, a flaw in the design of
the TSF, a flaw in the implementation of the TSF, etc. The description of the
security flaw's effects identifies the portions of the TSF that are affected and
how those portions are affected. For example, a security flaw in the
implementation might be found that affects the identification and
authentication enforced by the TSF by permitting authentication with the
password “BACKDOOR”.
ALC_FLR.3-3
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would identify the status of finding a
correction to each security flaw.
1142
The flaw remediation procedures identify the different stages of security
flaws. This differentiation includes at least: suspected security flaws that
have been reported, suspected security flaws that have been confirmed to be
security flaws, and security flaws whose solutions have been implemented. It
is permissible that additional stages (e.g. flaws that have been reported but
not yet investigated, flaws that are under investigation, security flaws for
which a solution has been found but not yet implemented) be included.
ALC_FLR.3.3C
The flaw remediation procedures shall require that corrective actions be
identified for each of the security flaws.
ALC_FLR.3-4
The evaluator shall check the flaw remediation procedures to determine that
the application of these procedures would identify the corrective action for
each security flaw.
1143
Corrective action may consist of a repair to the hardware, firmware, or
software portions of the TOE, a modification of TOE guidance, or both.
Corrective action that constitutes modifications to TOE guidance (e.g. details
of procedural measures to be taken to obviate the security flaw) includes
both those measures serving as only an interim solution (until the repair is
issued) as well as those serving as a permanent solution (where it is
determined that the procedural measure is the best solution).
1144
If the source of the security flaw is a documentation error, the corrective
action consists of an update of the affected TOE guidance. If the corrective
action is a procedural measure, this measure will include an update made to
the affected TOE guidance to reflect these corrective procedures.
ALC_FLR.3.4C
The flaw remediation procedures documentation shall describe the
methods used to provide flaw information, corrections and guidance on
corrective actions to TOE users.
ALC_FLR.3-5
The evaluator shall examine the flaw remediation procedures documentation
to determine that it describes a means of providing the TOE users with the
necessary information on each security flaw.
1145
The necessary information about each security flaw consists of its
description (not necessarily at the same level of detail as that provided as part
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of work unit ALC_FLR.3-2), the prescribed corrective action, and any
associated guidance on implementing the correction.
1146
TOE users may be provided with such information, correction, and
documentation updates in any of several ways, such as their posting to a
website, their being sent to TOE users, or arrangements made for the
developer to install the correction. In cases where the means of providing this
information requires action to be initiated by the TOE user, the evaluator
examines any TOE guidance to ensure that it contains instructions for
retrieving the information.
1147
The only metric for assessing the adequacy of the method used for providing
the information, corrections and guidance is that there be a reasonable
expectation that TOE users can obtain or receive it. For example, consider
the method of dissemination where the requisite data is posted to a website
for one month, and the TOE users know that this will happen and when this
will happen. This may not be especially reasonable or effective (as, say, a
permanent posting to the website), yet it is feasible that the TOE user could
obtain the necessary information. On the other hand, if the information were
posted to the website for only one hour, yet TOE users had no way of
knowing this or when it would be posted, it is infeasible that they would ever
get the necessary information.
1148
For TOE users who register with the developer (see work unit ALC_FLR.312), the passive availability of this information is not sufficient. Developers
must actively send the information (or a notification of its availability) to
registered TOE users.
ALC_FLR.3.5C
The flaw remediation procedures shall describe a means by which the
developer receives from TOE users reports and enquiries of suspected
security flaws in the TOE.
ALC_FLR.3-6
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would result in a means for the
developer to receive from TOE user reports of suspected security flaws or
requests for corrections to such flaws.
1149
The procedures ensure that TOE users have a means by which they can
communicate with the TOE developer. By having a means of contact with
the developer, the user can report security flaws, enquire about the status of
security flaws, or request corrections to flaws. This means of contact may be
part of a more general contact facility for reporting non-security related
problems.
1150
The use of these procedures is not restricted to TOE users; however, only the
TOE users are actively supplied with the details of these procedures. Others
who might have access to or familiarity with the TOE can use the same
procedures to submit reports to the developer, who is then expected to
process them. Any means of submitting reports to the developer, other than
those identified by the developer, are beyond the scope of this work unit;
reports generated by other means need not be addressed.
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ALC_FLR.3.6C
The flaw remediation procedures shall include a procedure requiring
timely response and the automatic distribution of security flaw reports and
the associated corrections to registered users who might be affected by the
security flaw.
ALC_FLR.3-7
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would result in a timely means of
providing the registered TOE users who might be affected with reports
about, and associated corrections to, each security flaw.
1151
The issue of timeliness applies to the issuance of both security flaw reports
and the associated corrections. However, these need not be issued at the
same time. It is recognised that flaw reports should be generated and issued
as soon as an interim solution is found, even if that solution is as drastic as
turn off the TOE. Likewise, when a more permanent (and less drastic)
solution is found, it should be issued without undue delay.
1152
It is unnecessary to restrict the recipients of the reports and associated
corrections to only those TOE users who might be affected by the security
flaw; it is permissible that all TOE users be given such reports and
corrections for all security flaws, provided such is done in a timely manner.
ALC_FLR.3-8
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would result in automatic distribution
of the reports and associated corrections to the registered TOE users who
might be affected.
1153
Automatic distribution does not mean that human interaction with the
distribution method is not permitted. In fact, the distribution method could
consist entirely of manual procedures, perhaps through a closely monitored
procedure with prescribed escalation upon the lack of issue of reports or
corrections.
1154
It is unnecessary to restrict the recipients of the reports and associated
corrections to only those TOE users who might be affected by the security
flaw; it is permissible that all TOE users be given such reports and
corrections for all security flaws, provided such is done automatically.
ALC_FLR.3.7C
The procedures for processing reported security flaws shall ensure that any
reported flaws are remediated and the remediation procedures issued to
TOE users.
ALC_FLR.3-9
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would help to ensure that every
reported flaw is remediated.
1155
The flaw remediation procedures cover not only those security flaws
discovered and reported by developer personnel, but also those reported by
TOE users. The procedures are sufficiently detailed so that they describe
how it is ensured that each reported security flaw is remediated. The
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procedures contain reasonable steps that show progress leading to the
eventual, inevitable resolution.
1156
The procedures describe the process that is taken from the point at which the
suspected security flaw is determined to be a security flaw to the point at
which it is resolved.
ALC_FLR.3-10
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would help to ensure that the TOE
users are issued remediation procedures for each security flaw.
1157
The procedures describe the process that is taken from the point at which a
security flaw is resolved to the point at which the remediation procedures are
provided. The procedures for delivering remediation procedures should be
consistent with the security objectives; they need not necessarily be identical
to the procedures used for delivering the TOE, as documented to meet
Delivery (ALC_DEL), if included in the assurance requirements. For
example, if the hardware portion of a TOE were originally delivered by
bonded courier, updates to hardware resulting from flaw remediation would
likewise be expected to be distributed by bonded courier. Updates unrelated
to flaw remediation would follow the procedures set forth in the
documentation meeting the Delivery (ALC_DEL) requirements.
ALC_FLR.3.8C
The procedures for processing reported security flaws shall provide
safeguards that any corrections to these security flaws do not introduce
any new flaws.
ALC_FLR.3-11
The evaluator shall examine the flaw remediation procedures to determine
that the application of these procedures would result in safeguards that the
potential correction contains no adverse effects.
1158
Through analysis, testing, or a combination of the two, the developer may
reduce the likelihood that adverse effects will be introduced when a security
flaw is corrected. The evaluator assesses whether the procedures provide
detail in how the necessary mix of analysis and testing actions is to be
determined for a given correction.
1159
The evaluator also determines that, for instances where the source of the
security flaw is a documentation problem, the procedures include the means
of safeguarding against the introduction of contradictions with other
documentation.
ALC_FLR.3.9C
The flaw remediation guidance shall describe a means by which TOE
users report to the developer any suspected security flaws in the TOE.
ALC_FLR.3-12
The evaluator shall examine the flaw remediation guidance to determine that
the application of these procedures would result in a means for the TOE user
to provide reports of suspected security flaws or requests for corrections to
such flaws.
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1160
The guidance ensures that TOE users have a means by which they can
communicate with the TOE developer. By having a means of contact with
the developer, the user can report security flaws, enquire about the status of
security flaws, or request corrections to flaws.
ALC_FLR.3.10C
The flaw remediation guidance shall describe a means by which TOE
users may register with the developer, to be eligible to receive security flaw
reports and corrections.
ALC_FLR.3-13
The evaluator shall examine the flaw remediation guidance to determine that
it describes a means of enabling the TOE users to register with the developer.
1161
Enabling the TOE users to register with the developer simply means having
a way for each TOE user to provide the developer with a point of contact;
this point of contact is to be used to provide the TOE user with information
related to security flaws that might affect that TOE user, along with any
corrections to the security flaw. Registering the TOE user may be
accomplished as part of the standard procedures that TOE users undergo to
identify themselves to the developer, for the purposes of registering a
software licence, or for obtaining update and other useful information.
1162
There need not be one registered TOE user per installation of the TOE; it
would be sufficient if there were one registered TOE user for an
organisation. For example, a corporate TOE user might have a centralised
acquisition office for all of its sites. In this case, the acquisition office would
be a sufficient point of contact for all of that TOE user's sites, so that all of
the TOE user's installations of the TOE have a registered point of contact.
1163
In either case, it must be possible to associate each TOE that is delivered
with an organisation in order to ensure that there is a registered user for each
TOE. For organisations that have many different addresses, this assures that
there will be no user who is erroneously presumed to be covered by a
registered TOE user.
1164
It should be noted that TOE users need not register; they must only be
provided with a means of doing so. However, users who choose to register
must be directly sent the information (or a notification of its availability).
ALC_FLR.3.11C
The flaw remediation guidance shall identify the specific points of contact
for all reports and enquiries about security issues involving the TOE.
ALC_FLR.3-14
The evaluator shall examine the flaw remediation guidance to determine that
it identifies specific points of contact for user reports and enquiries about
security issues involving the TOE.
1165
The guidance includes a means whereby registered TOE users can interact
with the developer to report discovered security flaws in the TOE or to make
enquiries regarding discovered security flaws in the TOE.
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13.7
Life-cycle definition (ALC_LCD)
13.7.1
Evaluation of sub-activity (ALC_LCD.1)
13.7.1.1
Objectives
1166
The objective of this sub-activity is to determine whether the developer has
used a documented model of the TOE life-cycle.
13.7.1.2
Input
1167
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the life-cycle definition documentation.
13.7.1.3
Action ALC_LCD.1.1E
ALC_LCD.1.1C
The life-cycle definition documentation shall describe the model used to
develop and maintain the TOE.
ALC_LCD.1-1
The evaluator shall examine the documented description of the life-cycle
model used to determine that it covers the development and maintenance
process.
1168
The description of the life-cycle model should include:
a)
information on the life-cycle phases of the TOE and the boundaries
between the subsequent phases;
b)
information on the procedures, tools and techniques used by the
developer (e.g. for design, coding, testing, bug-fixing);
c)
overall management structure governing the application of the
procedures (e.g. an identification and description of the individual
responsibilities for each of the procedures required by the
development and maintenance process covered by the life-cycle
model);
d)
information on which parts of the TOE are delivered by
subcontractors, if subcontractors are involved.
1169
Evaluation of sub-activity (ALC_LCD.1) does not require the model used to
conform to any standard life-cycle model.
ALC_LCD.1.2C
The life-cycle model shall provide for the necessary control over the
development and maintenance of the TOE.
ALC_LCD.1-2
The evaluator shall examine the life-cycle model to determine that use of the
procedures, tools and techniques described by the life-cycle model will make
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the necessary positive contribution to the development and maintenance of
the TOE.
1170
The information provided in the life-cycle model gives the evaluator
assurance that the development and maintenance procedures adopted would
minimise the likelihood of security flaws. For example, if the life-cycle
model described the review process, but did not make provision for
recording changes to components, then the evaluator may be less confident
that errors will not be introduced into the TOE. The evaluator may gain
further assurance by comparing the description of the model against an
understanding of the development process gleaned from performing other
evaluator actions relating to the TOE development (e.g. those covered under
the CM capabilities (ALC_CMC)). Identified deficiencies in the life-cycle
model will be of concern if they might reasonably be expected to give rise to
the introduction of flaws into the TOE, either accidentally or deliberately.
1171
The CC does not mandate any particular development approach, and each
should be judged on merit. For example, spiral, rapid-prototyping and
waterfall approaches to design can all be used to produce a quality TOE if
applied in a controlled environment.
13.7.2
Evaluation of sub-activity (ALC_LCD.2)
13.7.2.1
Objectives
1172
The objective of this sub-activity is to determine whether the developer has
used a documented and measurable model of the TOE life-cycle.
13.7.2.2
Input
1173
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the life-cycle definition documentation;
c)
information about the standard used;
d)
the life-cycle output documentation.
13.7.2.3
Action ALC_LCD.2.1E
ALC_LCD.2.1C
The life-cycle definition documentation shall describe the model used to
develop and maintain the TOE, including the details of its arithmetic
parameters and/or metrics used to measure the quality of the TOE and/or
its development.
ALC_LCD.2-1
The evaluator shall examine the documented description of the life-cycle
model used to determine that it covers the development and maintenance
process, including the details of its arithmetic parameters and/or metrics used
to measure the TOE development.
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1174
The description of the life-cycle model should include:
a)
information on the life-cycle phases of the TOE and the boundaries
between the subsequent phases;
b)
information on the procedures, tools and techniques used by the
developer (e.g. for design, coding, testing, bug-fixing);
c)
overall management structure governing the application of the
procedures (e.g. an identification and description of the individual
responsibilities for each of the procedures required by the
development and maintenance process covered by the life-cycle
model);
d)
information on which parts of the TOE are delivered by
subcontractors, if subcontractors are involved;
e)
information on the parameters/metrics that are used to measure the
TOE development. Metrics standards typically include guides for
measuring and producing reliable products and cover the aspects
reliability, quality, performance, complexity and cost. For the
evaluation all those metrics are of relevance, which are used to
increase quality by decreasing the probability of faults and thereby in
turn increase assurance in the security of the TOE.
ALC_LCD.2.2C
The life-cycle model shall provide for the necessary control over the
development and maintenance of the TOE.
ALC_LCD.2-2
The evaluator shall examine the life-cycle model to determine that use of the
procedures, tools and techniques described by the life-cycle model will make
the necessary positive contribution to the development and maintenance of
the TOE.
1175
The information provided in the life-cycle model gives the evaluator
assurance that the development and maintenance procedures adopted would
minimise the likelihood of security flaws. For example, if the life-cycle
model described the review process, but did not make provision for
recording changes to components, then the evaluator may be less confident
that errors will not be introduced into the TOE. The evaluator may gain
further assurance by comparing the description of the model against an
understanding of the development process gleaned from performing other
evaluator actions relating to the TOE development (e.g. those covered under
the CM capabilities (ALC_CMC)). Identified deficiencies in the life-cycle
model will be of concern if they might reasonably be expected to give rise to
the introduction of flaws into the TOE, either accidentally or deliberately.
1176
The CC does not mandate any particular development approach, and each
should be judged on merit. For example, spiral, rapid-prototyping and
waterfall approaches to design can all be used to produce a quality TOE if
applied in a controlled environment.
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1177
For the metrics/measurements used in the life-cycle model, evidence has to
be provided that shows how those metrics/measurements usefully contribute
to the minimisation of the likelihood of flaws. This can be viewed as the
overall goal for measurement in an ALC context. As a consequence the
metrics/measurements have to be selected based on their capability to
achieve that overall goal or contribute to that. In the first place a
metric/measure is suitable with respect to ALC if a correlation between the
metric/measure and the number of flaws can be stated with a certain degree
of reliability. But also a metric/measure useful for management purposes as
for planning and monitoring the TOE development are helpful since badly
managed projects are endangered to produce bad quality and to introduce
flaws.
1178
It may be possible to use metrics for quality improvement, for which this use
is not obvious. For example a metric to estimate the expected cost of a
product development may help quality, if the developer can show that this is
used to provide an adequate budget for development projects and that this
helps to avoid quality problems arising from resource shortages.
1179
It is not required that every single step in the life cycle of the TOE is
measurable. However the evaluator should see from the description of the
measures and procedures that the metrics are appropriate to control the
overall quality of the TOE and to minimise possible security flaws by this.
ALC_LCD.2.3C
The life-cycle output documentation shall provide the results of the
measurements of the TOE development using the measurable life-cycle
model.
ALC_LCD.2-3
The evaluator shall examine the life-cycle output documentation to
determine that it provides the results of the measurements of the TOE
development using the measurable life-cycle model.
1180
The results of the measurements and the life-cycle progress of the TOE
should be in accordance with the life-cycle model.
1181
The output documentation should not only include numeric values of the
metrics but should also document actions taken as a result of the
measurements and in accordance with the model. For example there may be
a requirement that a certain design phase needs to be repeated, if some error
rates measured during testing are outside of a defined threshold. In this case
the documentation should show that such action was taken, if indeed the
thresholds were not met.
1182
If the evaluation is conducted in parallel with the development of the TOE it
may be possible that quality measurements have not been used in the past. In
this case the evaluator should use the documentation of the planned
procedures in order to gain confidence that corrective actions are defined if
results of quality measurements deviate from some threshold.
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13.8
Tools and techniques (ALC_TAT)
13.8.1
Evaluation of sub-activity (ALC_TAT.1)
13.8.1.1
Objectives
1183
The objective of this sub-activity is to determine whether the developer has
used well-defined development tools (e.g. programming languages or
computer-aided design (CAD) systems) that yield consistent and predictable
results.
13.8.1.2
Input
1184
The evaluation evidence for this sub-activity is:
a)
the development tool documentation;
b)
the subset of the implementation representation.
13.8.1.3
Application notes
1185
This work may be performed in parallel with the evaluation activities under
Implementation representation (ADV_IMP), specifically with regard to
determining the use of features in the tools that will affect the object code
(e.g. compilation options).
13.8.1.4
Action ALC_TAT.1.1E
ALC_TAT.1.1C
Each development tool used for implementation shall be well-defined.
ALC_TAT.1-1
The evaluator shall examine the development tool documentation provided
to determine that each development tools is well-defined.
1186
For example, a well-defined language, compiler or CAD system may be
considered to be one that conforms to a recognised standard, such as the ISO
standards. A well-defined language is one that has a clear and complete
description of its syntax, and a detailed description of the semantics of each
construct.
ALC_TAT.1.2C
The documentation of each development tool shall unambiguously define
the meaning of all statements as well as all conventions and directives used
in the implementation.
ALC_TAT.1-2
The evaluator shall examine the documentation of each development tool to
determine that it unambiguously defines the meaning of all statements as
well as all conventions and directives used in the implementation.
1187
The development tool documentation (e.g. programming language
specifications and user manuals) should cover all statements used in the
implementation representation of the TOE, and for each such statement
should provide a clear and unambiguous definition of the purpose and effect
of that statement. This work may be performed in parallel with the
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evaluator's examination of the implementation representation performed
during the ADV_IMP sub-activity. The key test the evaluator should apply is
whether or not the documentation is sufficiently clear for the evaluator to be
able to understand the implementation representation. The documentation
should not assume (for example) that the reader is an expert in the
programming language used.
1188
Reference to the use of a documented standard is an acceptable approach to
meet this requirement, provided that the standard is available to the
evaluator. Any differences from the standard should be documented.
1189
The critical test is whether the evaluator can understand the TOE source code
when performing source code analysis covered in the ADV_IMP subactivity. However, the following checklist can additionally be used in
searching for problem areas:
a)
In the language definition, phrases such as “the effect of this
construct is undefined” and terms such as “implementation
dependent” or “erroneous” may indicate ill-defined areas.
b)
Aliasing (allowing the same piece of memory to be referenced in
different ways) is a common source of ambiguity problems.
c)
Exception handling (e.g. what happens after memory exhaustion or
stack overflow) is often poorly defined.
1190
Most languages in common use, however well designed, will have some
problematic constructs. If the implementation language is mostly well
defined, but some problematic constructs exist, then an inconclusive verdict
should be assigned, pending examination of the source code.
1191
The evaluator should verify, during the examination of source code, that any
use of the problematic constructs does not introduce vulnerabilities. The
evaluator should also ensure that constructs precluded by the documented
standard are not used.
1192
The development tool documentation should define all conventions and
directives used in the implementation.
ALC_TAT.1.3C
The documentation of each development tool shall unambiguously define
the meaning of all implementation-dependent options.
ALC_TAT.1-3
The evaluator shall examine the development tool documentation to
determine that it unambiguously defines the meaning of all implementationdependent options.
1193
The documentation of software development tools should include definitions
of implementation-dependent options that may affect the meaning of the
executable code, and those that are different from the standard language as
documented. Where source code is provided to the evaluator, information
should also be provided on compilation and linking options used.
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1194
The documentation for hardware design and development tools should
describe the use of all options that affect the output from the tools (e.g.
detailed hardware specifications, or actual hardware).
13.8.2
Evaluation of sub-activity (ALC_TAT.2)
13.8.2.1
Objectives
1195
The objective of this sub-activity is to determine whether the developer has
used well-defined development tools (e.g. programming languages or
computer-aided design (CAD) systems) that yield consistent and predictable
results, and whether implementation standards have been applied.
13.8.2.2
Input
1196
The evaluation evidence for this sub-activity is:
a)
the development tool documentation;
b)
the implementation standards description;
c)
the provided implementation representation of the TSF.
13.8.2.3
Application notes
1197
This work may be performed in parallel with the evaluation activities under
ADV_IMP, specifically with regard to determining the use of features in the
tools that will affect the object code (e.g. compilation options).
13.8.2.4
Action ALC_TAT.2.1E
ALC_TAT.2.1C
Each development tool used for implementation shall be well-defined.
ALC_TAT.2-1
The evaluator shall examine the development tool documentation provided
to determine that each development tool is well-defined.
1198
For example, a well-defined language, compiler or CAD system may be
considered to be one that conforms to a recognised standard, such as the ISO
standards. A well-defined language is one that has a clear and complete
description of its syntax, and a detailed description of the semantics of each
construct.
ALC_TAT.2.2C
The documentation of each development tool shall unambiguously define
the meaning of all statements as well as all conventions and directives used
in the implementation.
ALC_TAT.2-2
The evaluator shall examine the documentation of each development tool to
determine that it unambiguously defines the meaning of all statements as
well as all conventions and directives used in the implementation.
1199
The development tool documentation (e.g. programming language
specifications and user manuals) should cover all statements used in the
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implementation representation of the TOE, and for each such statement
should provide a clear and unambiguous definition of the purpose and effect
of that statement. This work may be performed in parallel with the
evaluator's examination of the implementation representation performed
during the ADV_IMP sub-activity. The key test the evaluator should apply is
whether or not the documentation is sufficiently clear for the evaluator to be
able to understand the implementation representation. The documentation
should not assume (for example) that the reader is an expert in the
programming language used.
1200
Reference to the use of a documented standard is an acceptable approach to
meet this requirement, provided that the standard is available to the
evaluator. Any differences from the standard should be documented.
1201
The critical test is whether the evaluator can understand the TOE source code
when performing source code analysis covered in the ADV_IMP subactivity. However, the following checklist can additionally be used in
searching for problem areas:
a)
In the language definition, phrases such as “the effect of this
construct is undefined” and terms such as “implementation
dependent” or “erroneous” may indicate ill-defined areas.
b)
Aliasing (allowing the same piece of memory to be referenced in
different ways) is a common source of ambiguity problems.
c)
Exception handling (e.g. what happens after memory exhaustion or
stack overflow) is often poorly defined.
1202
Most languages in common use, however well designed, will have some
problematic constructs. If the implementation language is mostly well
defined, but some problematic constructs exist, then an inconclusive verdict
should be assigned, pending examination of the source code.
1203
The evaluator should verify, during the examination of source code, that any
use of the problematic constructs does not introduce vulnerabilities. The
evaluator should also ensure that constructs precluded by the documented
standard are not used.
1204
The development tool documentation should define all conventions and
directives used in the implementation.
ALC_TAT.2.3C
The documentation of each development tool shall unambiguously define
the meaning of all implementation-dependent options.
ALC_TAT.2-3
The evaluator shall examine the development tool documentation to
determine that it unambiguously defines the meaning of all implementationdependent options.
1205
The documentation of software development tools should include definitions
of implementation-dependent options that may affect the meaning of the
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executable code, and those that are different from the standard language as
documented. Where source code is provided to the evaluator, information
should also be provided on compilation and linking options used.
1206
The documentation for hardware design and development tools should
describe the use of all options that affect the output from the tools (e.g.
detailed hardware specifications, or actual hardware).
13.8.2.5
Action ALC_TAT.2.2E
ALC_TAT.2-4
The evaluator shall examine aspects of the implementation process to
determine that documented implementation standards have been applied.
1207
This work unit requires the evaluator to analyse the provided implementation
representation of the TOE to determine whether the documented
implementation standards have been applied.
1208
The evaluator should verify that constructs excluded by the documented
standard are not used.
1209
Additionally, the evaluator should verify the developer's procedures which
ensure the application of the defined standards within the design and
implementation process of the TOE. Therefore, documentary evidence
should be supplemented by visiting the development environment. A visit to
the development environment will allow the evaluator to:
a)
observe the application of defined standards;
b)
examine documentary evidence of application of procedures
describing the use of defined standards;
c)
interview development staff to check awareness of the application of
defined standards and procedures.
1210
A development site visit is a useful means of gaining confidence in the
procedures being used. Any decision not to make such a visit should be
determined in consultation with the evaluation authority.
1211
The evaluator compares the provided implementation representation with the
description of the applied implementation standards and verifies their use.
1212
At this level it is not required that the complete provided implementation
representation of the TSF is based on implementation standards, but only
those parts that are developed by the TOE developer himself. The evaluator
may consult the configuration list required by the CM scope (ALC_CMS) to
get the information which parts are developed by the TOE developer, and
which by third party developers.
1213
If the referenced implementation standards are not applied for at least parts
of the provided implementation representation, this work unit fails.
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1214
Note that parts of the TOE which are not TSF relevant do not need to be
examined.
1215
This work unit may be performed in conjunction with the evaluation
activities under ADV_IMP.
13.8.3
Evaluation of sub-activity (ALC_TAT.3)
13.8.3.1
Objectives
1216
The objective of this sub-activity is to determine whether the developer and
his subcontractors have used well-defined development tools (e.g.
programming languages or computer-aided design (CAD) systems) that yield
consistent and predictable results, and whether implementation standards
have been applied.
13.8.3.2
Input
1217
The evaluation evidence for this sub-activity is:
a)
the development tool documentation;
b)
the implementation standards description;
c)
the provided implementation representation of the TSF.
13.8.3.3
Application notes
1218
This work may be performed in parallel with the evaluation activities under
ADV_IMP, specifically with regard to determining the use of features in the
tools that will affect the object code (e.g. compilation options).
13.8.3.4
Action ALC_TAT.3.1E
ALC_TAT.3.1C
Each development tool used for implementation shall be well-defined.
ALC_TAT.3-1
The evaluator shall examine the development tool documentation provided
to determine that each development tool is well-defined.
1219
For example, a well-defined language, compiler or CAD system may be
considered to be one that conforms to a recognised standard, such as the ISO
standards. A well-defined language is one that has a clear and complete
description of its syntax, and a detailed description of the semantics of each
construct.
1220
At this level, the documentation of development tools used by third party
contributors to the TOE has to be included in the evaluator's examination.
ALC_TAT.3.2C
The documentation of each development tool shall unambiguously define
the meaning of all statements as well as all conventions and directives used
in the implementation.
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ALC_TAT.3-2
The evaluator shall examine the documentation of each development tool to
determine that it unambiguously defines the meaning of all statements as
well as all conventions and directives used in the implementation.
1221
The development tool documentation (e.g. programming language
specifications and user manuals) should cover all statements used in the
implementation representation of the TOE, and for each such statement
should provide a clear and unambiguous definition of the purpose and effect
of that statement. This work may be performed in parallel with the
evaluator's examination of the implementation representation performed
during the ADV_IMP sub-activity. The key test the evaluator should apply is
whether or not the documentation is sufficiently clear for the evaluator to be
able to understand the implementation representation. The documentation
should not assume (for example) that the reader is an expert in the
programming language used.
1222
Reference to the use of a documented standard is an acceptable approach to
meet this requirement, provided that the standard is available to the
evaluator. Any differences from the standard should be documented.
1223
The critical test is whether the evaluator can understand the TOE source code
when performing source code analysis covered in the ADV_IMP subactivity. However, the following checklist can additionally be used in
searching for problem areas:
a)
In the language definition, phrases such as “the effect of this
construct is undefined” and terms such as “implementation
dependent” or “erroneous” may indicate ill-defined areas.
b)
Aliasing (allowing the same piece of memory to be referenced in
different ways) is a common source of ambiguity problems.
c)
Exception handling (e.g. what happens after memory exhaustion or
stack overflow) is often poorly defined.
1224
Most languages in common use, however well designed, will have some
problematic constructs. If the implementation language is mostly well
defined, but some problematic constructs exist, then an inconclusive verdict
should be assigned, pending examination of the source code.
1225
The evaluator should verify, during the examination of source code, that any
use of the problematic constructs does not introduce vulnerabilities. The
evaluator should also ensure that constructs precluded by the documented
standard are not used.
1226
The development tool documentation should define all conventions and
directives used in the implementation.
1227
At this level, the documentation of development tools used by third party
contributors to the TOE has to be included in the evaluator's examination.
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ALC_TAT.3.3C
The documentation of each development tool shall unambiguously define
the meaning of all implementation-dependent options.
ALC_TAT.3-3
The evaluator shall examine the development tool documentation to
determine that it unambiguously defines the meaning of all implementationdependent options.
1228
The documentation of software development tools should include definitions
of implementation-dependent options that may affect the meaning of the
executable code, and those that are different from the standard language as
documented. Where source code is provided to the evaluator, information
should also be provided on compilation and linking options used.
1229
The documentation for hardware design and development tools should
describe the use of all options that affect the output from the tools (e.g.
detailed hardware specifications, or actual hardware).
1230
At this level, the documentation of development tools used by third party
contributors to the TOE has to be included in the evaluator's examination.
13.8.3.5
Action ALC_TAT.3.2E
ALC_TAT.3-4
The evaluator shall examine aspects of the implementation process to
determine that documented implementation standards have been applied.
1231
This work unit requires the evaluator to analyse the provided implementation
representation of the TOE to determine whether the documented
implementation standards have been applied.
1232
The evaluator should verify that constructs excluded by the documented
standard are not used.
1233
Additionally, the evaluator should verify the developer's procedures which
ensure the application of the defined standards within the design and
implementation process of the TOE. Therefore, documentary evidence
should be supplemented by visiting the development environment. A visit to
the development environment will allow the evaluator to:
a)
observe the application of defined standards;
b)
examine documentary evidence of application of procedures
describing the use of defined standards;
c)
interview development staff to check awareness of the application of
defined standards and procedures.
1234
A development site visit is a useful means of gaining confidence in the
procedures being used. Any decision not to make such a visit should be
determined in consultation with the evaluation authority.
1235
The evaluator compares the provided implementation representation with the
description of the applied implementation standards and verifies their use.
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1236
At this level it is required that the complete provided implementation
representation of the TSF is based on implementation standards, including
third party contributions. This may require the evaluator to visit the sites of
contributors. The evaluator may consult the configuration list required by the
CM scope (ALC_CMS) to see who has developed which part of the TOE.
1237
Note that parts of the TOE which are not TSF relevant do not need to be
examined.
1238
This work unit may be performed in conjunction with the evaluation
activities under ADV_IMP.
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14
Class ATE: Tests
14.1
Introduction
1239
The goal of this activity is to determine whether the TOE behaves as
described in the ST and as specified in the evaluation evidence (described in
the ADV class). This determination is achieved through some combination of
the developer's own functional testing of the TSF (Functional tests
(ATE_FUN)) and independent testing the TSF by the evaluator (Independent
testing (ATE_IND)). At the lowest level of assurance, there is no
requirement for developer involvement, so the only testing is conducted by
the evaluator, using the limited available information about the TOE.
Additional assurance is gained as the developer becomes increasingly
involved both in testing and in providing additional information about the
TOE, and as the evaluator increases the independent testing activities.
14.2
Application notes
1240
Testing of the TSF is conducted by the evaluator and, in most cases, by the
developer. The evaluator's testing efforts consist not only of creating and
running original tests, but also of assessing the adequacy of the developer's
tests and re-running a subset of them.
1241
The evaluator analyses the developer's tests to determine the extent to which
they are sufficient to demonstrate that TSFI (see Functional specification
(ADV_FSP)) perform as specified, and to understand the developer's
approach to testing. Similarly, the evaluator analyses the developer's tests to
determine the extent to which they are sufficient to demonstrate the internal
behaviour and properties of the TSF.
1242
The evaluator also executes a subset of the developer's tests as documented
to gain confidence in the developer's test results: the evaluator will use the
results of this analysis as an input to independently testing a subset of the
TSF. With respect to this subset, the evaluator takes a testing approach that is
different from that of the developer, particularly if the developer's tests have
shortcomings.
1243
To determine the adequacy of developer's test documentation or to create
new tests, the evaluator needs to understand the desired expected behaviour
of the TSF, both internally and as seen at the TSFI, in the context of the
SFRs it is to satisfy. The evaluator may choose to divide the TSF and TSFI
into subsets according to functional areas of the ST (audit subsystem, auditrelated TSFI, authentication module, authentication-related TSFI, etc.) if
they were not already divided in the ST, and focus on one subset of the at a
time, examining the ST requirement and the relevant parts of the
development and guidance documentation to gain an understanding of the
way the TOE is expected to behave. This reliance upon the development
documentation underscores the need for the dependencies on ADV by
Coverage (ATE_COV) and Depth (ATE_DPT).
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1244
The CC has separated coverage and depth from functional tests to increase
the flexibility when applying the components of the families. However, the
requirements of the families are intended to be applied together to confirm
that the TSF operates according to its specification. This tight coupling of
families has led to some duplication of evaluator work units across subactivities. These application notes are used to minimise duplication of text
between sub-activities.
14.2.1
Understanding the expected behaviour of the TOE
1245
Before the adequacy of test documentation can be accurately evaluated, or
before new tests can be created, the evaluator has to understand the desired
expected behaviour of a security function in the context of the requirements
it is to satisfy.
1246
As mentioned earlier, the evaluator may choose to subset the TSF and TSFI
according to SFRs (audit, authentication, etc.) in the ST and focus on one
subset at a time. The evaluator examines each ST requirement and the
relevant parts of the functional specification and guidance documentation to
gain an understanding of the way the related TSFI is expected to behave.
Similarly, the evaluator examines the relevant parts of the TOE design and
security architecture documentation to gain an understanding of the way the
related modules or subsystems of the TSF are expected to behave.
1247
With an understanding of the expected behaviour, the evaluator examines the
test plan to gain an understanding of the testing approach. In most cases, the
testing approach will entail a TSFI being stimulated and its responses
observed. Externally-visible functionality can be tested directly; however, in
cases where functionality is not visible external to the TOE (for example,
testing the residual information protection functionality), other means will
need to be employed.
14.2.2
Testing vs. alternate approaches to verify the expected
behaviour of functionality
1248
In cases where it is impractical or inadequate to test specific functionality
(where it provides no externally-visible TSFI), the test plan should identify
the alternate approach to verify expected behaviour. It is the evaluator's
responsibility to determine the suitability of the alternate approach. However,
the following should be considered when assessing the suitability of alternate
approaches:
a)
an analysis of the implementation representation to determine that the
required behaviour should be exhibited by the TOE is an acceptable
alternate approach. This could mean a code inspection for a software
TOE or perhaps a chip mask inspection for a hardware TOE.
b)
it is acceptable to use evidence of developer integration or module
testing, even if the claimed assurance requirements do not include
availability of lower level descriptions of the TOE modules (e.g.
Evaluation of sub-activity (ADV_TDS.3)) or implementation
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(Implementation representation (ADV_IMP)). If evidence of
developer integration or module testing is used in verifying the
expected behaviour of a security functionality, care should be given
to confirm that the testing evidence reflects the current
implementation of the TOE. If the subsystems or modules have been
changed since testing occurred, evidence that the changes were
tracked and addressed by analysis or further testing will usually be
required.
1249
It should be emphasised that supplementing the testing effort with alternate
approaches should only be undertaken when both the developer and
evaluator determine that there exists no other practical means to test the
expected behaviour.
14.2.3
Verifying the adequacy of tests
1250
Test pre-requisites are necessary to establish the required initial conditions
for the test. They may be expressed in terms of parameters that must be set or
in terms of test ordering in cases where the completion of one test establishes
the necessary pre-requisites for another test. The evaluator must determine
that the pre-requisites are complete and appropriate in that they will not bias
the observed test results towards the expected test results.
1251
The test steps and expected results specify the actions and parameters to be
applied to the TSFI as well as how the expected results should be verified
and what they are. The evaluator must determine that the test steps and
expected results are consistent with the descriptions of the TSFI in the
functional specification. This means that each characteristic of the TSFI
behaviour explicitly described in the functional specification should have
tests and expected results to verify that behaviour.
1252
The overall aim of this testing activity is to determine that each subsystem,
module, and TSFI has been sufficiently tested against the behavioural claims
in the functional specification, TOE design, and architecture description. At
the higher assurance levels, testing also includes bounds testing and negative
testing. The test procedures will provide insight as to how the TSFIs,
modules, and subsystems have been exercised by the developer during
testing. The evaluator uses this information when developing additional tests
to independently test the TSF.
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14.3
Coverage (ATE_COV)
14.3.1
Evaluation of sub-activity (ATE_COV.1)
14.3.1.1
Objectives
1253
The objective of this sub-activity is to determine whether the developer has
tested the TSFIs, and that the developer's test coverage evidence shows
correspondence between the tests identified in the test documentation and the
TSFIs described in the functional specification.
14.3.1.2
Input
1254
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the test documentation;
d)
the test coverage evidence.
14.3.1.3
Application notes
1255
The coverage analysis provided by the developer is required to show the
correspondence between the tests provided as evaluation evidence and the
functional specification. However, the coverage analysis need not
demonstrate that all TSFI have been tested, or that all externally-visible
interfaces to the TOE have been tested. Such shortcomings are considered by
the evaluator during the independent testing (Evaluation of sub-activity
(ATE_IND.2)) sub-activity.
14.3.1.4
Action ATE_COV.1.1E
ATE_COV.1.1C
The evidence of the test coverage shall show the correspondence between
the tests in the test documentation and the TSFIs in the functional
specification.
ATE_COV.1-1
The evaluator shall examine the test coverage evidence to determine that the
correspondence between the tests identified in the test documentation and the
TSFIs described in the functional specification is accurate.
1256
Correspondence may take the form of a table or matrix. The coverage
evidence required for this component will reveal the extent of coverage,
rather than to show complete coverage. In cases where coverage is shown to
be poor the evaluator should increase the level of independent testing to
compensate.
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14.3.2
Evaluation of sub-activity (ATE_COV.2)
14.3.2.1
Objectives
1257
The objective of this sub-activity is to determine whether the developer has
tested all of the TSFIs, and that the developer's test coverage evidence shows
correspondence between the tests identified in the test documentation and the
TSFIs described in the functional specification.
14.3.2.2
Input
a)
the ST;
b)
the functional specification;
c)
the test documentation;
d)
the test coverage analysis.
14.3.2.3
Action ATE_COV.2.1E
ATE_COV.2.1C
The analysis of the test coverage shall demonstrate the correspondence
between the tests in the test documentation and the TSFIs in the functional
specification.
ATE_COV.2-1
The evaluator shall examine the test coverage analysis to determine that the
correspondence between the tests in the test documentation and the interfaces
in the functional specification is accurate.
1258
A simple cross-table may be sufficient to show test correspondence. The
identification of the tests and the interfaces presented in the test coverage
analysis has to be unambiguous.
1259
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to interfaces in the functional specification.
ATE_COV.2-2
The evaluator shall examine the test plan to determine that the testing
approach for each interface demonstrates the expected behaviour of that
interface.
1260
Guidance on this work unit can be found in:
a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
ATE_COV.2-3
The evaluator shall examine the test procedures to determine that the test
prerequisites, test steps and expected result(s) adequately test each interface.
1261
Guidance on this work units, as it pertains to the functional specification, can
be found in:
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a)
14.2.3, Verifying the adequacy of tests
ATE_COV.2.2C
The analysis of the test coverage shall demonstrate that all TSFIs in the
functional specification have been tested.
ATE_COV.2-4
The evaluator shall examine the test coverage analysis to determine that the
correspondence between the interfaces in the functional specification and the
tests in the test documentation is complete.
1262
All TSFIs that are described in the functional specification have to be present
in the test coverage analysis and mapped to tests in order for completeness to
be claimed, although exhaustive specification testing of interfaces is not
required. Incomplete coverage would be evident if an interface was identified
in the functional specification and no test was mapped to it.
1263
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to interfaces in the functional specification.
14.3.3
Evaluation of sub-activity (ATE_COV.3)
1264
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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14.4
Depth (ATE_DPT)
14.4.1
Evaluation of sub-activity (ATE_DPT.1)
14.4.1.1
Objectives
1265
The objective of this sub-activity is to determine whether the developer has
tested the TSF subsystems against the TOE design and the security
architecture description.
14.4.1.2
Input
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the test documentation;
f)
the depth of testing analysis.
14.4.1.3
Action ATE_DPT.1.1E
ATE_DPT.1.1C
The analysis of the depth of testing shall demonstrate the correspondence
between the tests in the test documentation and the TSF subsystems in the
TOE design.
ATE_DPT.1-1
The evaluator shall examine the depth of testing analysis to determine that
the descriptions of the behaviour of TSF subsystems and of their interactions
is included within the test documentation.
1266
This work unit verifies the content of the correspondence between the tests
and the descriptions in the TOE design. In cases where the description of the
TSF's architectural soundness (in Security Architecture (ADV_ARC)) cites
specific mechanisms, this work unit also verifies the correspondence
between the tests and the descriptions of the behaviour of such mechanisms.
1267
A simple cross-table may be sufficient to show test correspondence. The
identification of the tests and the behaviour/interaction presented in the
depth-of coverage analysis has to be unambiguous.
1268
The evaluator is reminded that not all tests in the test documentation must
map to a subsystem behaviour or interaction description.
ATE_DPT.1-2
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for the behaviour
description demonstrates the behaviour of that subsystem as described in the
TOE design.
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1269
Guidance on this work unit can be found in:
a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1270
If TSF subsystem interfaces are described, the behaviour of those subsystems
may be tested directly from those interfaces. Otherwise, the behaviour of
those subsystems is tested from the TSFI interfaces. Or a combination of the
two may be employed. Whatever strategy is used the evaluator will consider
its appropriateness for adequately testing the behaviour that is described in
the TOE design.
ATE_DPT.1-3
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for the behaviour
description demonstrates the interactions among subsystems as described in
the TOE design.
1271
While the previous work unit addresses behaviour of subsystems, this work
unit addresses the interactions among work units.
1272
Guidance on this work unit can be found in:
a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1273
If TSF subsystem interfaces are described, the interactions with other
subsystems may be tested directly from those interfaces. Otherwise, the
interactions among subsystems must be inferred from the TSFI interfaces.
Whatever strategy is used the evaluator will consider its appropriateness for
adequately testing the interactions among subsystems that are described in
the TOE design.
ATE_DPT.1.2C
The analysis of the depth of testing shall demonstrate that all TSF
subsystems in the TOE design have been tested.
ATE_DPT.1-4
The evaluator shall examine the test procedures to determine that all
descriptions of TSF subsystem behaviour and interaction are tested.
1274
This work unit verifies the completeness of work unit ATE_DPT.1-1. All
descriptions of TSF subsystem behaviour and of interactions among TSF
subsystems that are provided in the TOE design have to be tested.
Incomplete depth of testing would be evident if a description of TSF
subsystem behaviour or of interactions among TSF subsystems was
identified in the TOE design and no tests could be attributed to it.
1275
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to component interfaces in the TOE design.
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14.4.2
Evaluation of sub-activity (ATE_DPT.2)
14.4.2.1
Objectives
1276
The objective of this sub-activity is to determine whether the developer has
tested the TSF subsystems against the TOE design and the security
architecture description.
14.4.2.2
Input
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the test documentation;
f)
the depth of testing analysis.
14.4.2.3
Action ATE_DPT.2.1E
ATE_DPT.2.1C
The analysis of the depth of testing shall demonstrate the correspondence
between the tests in the test documentation and the TSF subsystems and
modules in the TOE design.
ATE_DPT.2-1
The evaluator shall examine the depth of testing analysis to determine that
descriptions of the behaviour of TSF subsystems and of their interactions are
included within the test documentation.
1277
This work unit verifies the content of the correspondence between the tests
and the descriptions in the TOE design. In cases where the description of the
TSF's architectural soundness (in Security Architecture (ADV_ARC)) cites
specific mechanisms, this work unit also verifies the correspondence
between the tests and the descriptions of the behaviour of such mechanisms.
1278
A simple cross-table may be sufficient to show test correspondence. The
identification of the tests and the behaviour/interaction presented in the
depth-of coverage analysis has to be unambiguous.
1279
The evaluator is reminded that not all tests in the test documentation must
map to a subsystem behaviour or interaction description.
ATE_DPT.2-2
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for the behaviour
description demonstrates the behaviour of that subsystem as described in the
TOE design.
1280
Guidance on this work unit can be found in:
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a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1281
If TSF subsystem interfaces are described, the behaviour of those subsystems
may be tested directly from those interfaces. Otherwise, the behaviour of
those subsystems is tested from the TSFI interfaces. Or a combination of the
two may be employed. Whatever strategy is used the evaluator will consider
its appropriateness for adequately testing the behaviour that is described in
the TOE design.
ATE_DPT.2-3
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for the behaviour
description demonstrates the interactions among subsystems as described in
the TOE design.
1282
While the previous work unit addresses behaviour of subsystems, this work
unit addresses the interactions among work units.
1283
Guidance on this work unit can be found in:
a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1284
If TSF subsystem interfaces are described, the interactions with other
subsystems may be tested directly from those interfaces. Otherwise, the
interactions among subsystems must be inferred from the TSFI interfaces.
Whatever strategy is used the evaluator will consider its appropriateness for
adequately testing the interactions among subsystems that are described in
the TOE design.
ATE_DPT.2-4
The evaluator shall examine the depth of testing analysis to determine that
the interfaces of SFR-enforcing modules are included within the test
documentation.
1285
This work unit verifies the content of the correspondence between the tests
and the descriptions in the TOE design. In cases where the description of the
TSF's architectural soundness (in Security Architecture (ADV_ARC)) cites
specific mechanisms at the modular level, this work unit also verifies the
correspondence between the tests and the descriptions of the behaviour of
such mechanisms.
1286
A simple cross-table may be sufficient to show test correspondence. The
identification of the tests and the behaviour/interaction presented in the
depth-of coverage analysis has to be unambiguous.
1287
The evaluator is reminded that not all tests in the test documentation must
map to a subsystem behaviour or interaction description.
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ATE_DPT.2-5
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for each TSF
module interface demonstrates the expected behaviour of that interface.
1288
While work unit ATE_DPT.2-1 addresses expected behaviour of subsystems,
this work unit addresses expected behaviour of the TSF module interfaces
that are covered by ATE_DPT.2-4.
1289
Guidance on this work unit can be found in:
a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1290
Testing of an interface may be performed directly at that interface, or at the
external interfaces, or a combination of both. Whatever strategy is used the
evaluator will consider its appropriateness for adequately testing the
interfaces. Specifically the evaluator determines whether testing at the
internal interfaces is necessary or whether these internal interfaces can be
adequately tested (albeit implicitly) by exercising the external interfaces.
This determination is left to the evaluator, as is its justification.
ATE_DPT.2.2C
The analysis of the depth of testing shall demonstrate that all TSF
subsystems in the TOE design have been tested.
ATE_DPT.2-6
The evaluator shall examine the test procedures to determine that all
descriptions of TSF subsystem behaviour and interaction are tested.
1291
This work unit verifies the completeness of work unit ATE_DPT.2-1. All
descriptions of TSF subsystem behaviour and of interactions among TSF
subsystems that are provided in the TOE design have to be tested.
Incomplete depth of testing would be evident if a description of TSF
subsystem behaviour or of interactions among TSF subsystems was
identified in the TOE design and no tests could be attributed to it.
1292
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to component interfaces in the TOE design.
ATE_DPT.2.3C
The analysis of the depth of testing shall demonstrate that the SFRenforcing modules in the TOE design have been tested.
ATE_DPT.2-7
The evaluator shall examine the test procedures to determine that all
interfaces of SFR-enforcing modules are tested.
1293
This work unit verifies the completeness of work unit ATE_DPT.2-4. All
interfaces of SFR-enforcing modules that are provided in the TOE design
have to be tested. Incomplete depth of testing would be evident if any
interface of any SFR-enforcing modules was identified in the TOE design
and no tests could be attributed to it.
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1294
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to an interface of an SFR-enforcing module in the
TOE design.
14.4.3
Evaluation of sub-activity (ATE_DPT.3)
14.4.3.1
Objectives
1295
The objective of this sub-activity is to determine whether the developer has
tested the TSF subsystems against the TOE design and the security
architecture description.
14.4.3.2
Input
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the test documentation;
f)
the depth of testing analysis.
14.4.3.3
Action ATE_DPT.3.1E
ATE_DPT.3.1C
The analysis of the depth of testing shall demonstrate the correspondence
between the tests in the test documentation and the TSF subsystems and
modules in the TOE design.
ATE_DPT.3-1
The evaluator shall examine the depth of testing analysis to determine that
descriptions of the behaviour of TSF subsystems and of their interactions are
included within the test documentation.
1296
This work unit verifies the content of the correspondence between the tests
and the descriptions in the TOE design. A simple cross-table may be
sufficient to show test correspondence. The identification of the tests and the
behaviour/interaction presented in the depth-of coverage analysis has to be
unambiguous.
1297
The evaluator is reminded that not all tests in the test documentation must
map to a subsystem behaviour or interaction description.
ATE_DPT.3-2
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for the behaviour
description demonstrates the behaviour of that subsystem as described in the
TOE design.
1298
Guidance on this work unit can be found in:
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a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1299
If TSF subsystem interfaces are provided, the behaviour of those subsystems
may be performed directly from those interfaces. Otherwise, the behaviour of
those subsystems is tested from the TSFI interfaces. Or a combination of the
two may be employed. Whatever strategy is used the evaluator will consider
its appropriateness for adequately testing the behaviour that is described in
the TOE design.
ATE_DPT.3-3
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for the behaviour
description demonstrates the interactions among subsystems as described in
the TOE design.
1300
Guidance on this work unit can be found in:
a)
14.2.1, Understanding the expected behaviour of the TOE
b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1301
If TSF subsystem interfaces are provided, the interactions with other
subsystems may be performed directly from those interfaces. Otherwise, the
interactions among subsystems must be inferred from the TSFI interfaces.
Whatever strategy is used the evaluator will consider its appropriateness for
adequately testing the interactions among subsystems that are described in
the TOE design.
ATE_DPT.3-4
The evaluator shall examine the depth of testing analysis to determine that
the interfaces of TSF modules are included within the test documentation.
1302
This work unit verifies the content of the correspondence between the tests
and the descriptions in the TOE design. A simple cross-table may be
sufficient to show test correspondence. The identification of the tests and the
behaviour/interaction presented in the depth-of coverage analysis has to be
unambiguous.
1303
The evaluator is reminded that not all tests in the test documentation must
map to a subsystem behaviour or interaction description.
ATE_DPT.3-5
The evaluator shall examine the test plan, test prerequisites, test steps and
expected result(s) to determine that the testing approach for each TSF
module interface demonstrates the expected behaviour of that interface.
1304
Guidance on this work unit can be found in:
a)
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b)
14.2.2, Testing vs. alternate approaches to verify the expected
behaviour of functionality
1305
Testing of an interface may be performed directly at that interface, or at the
external interfaces, or a combination of both. Whatever strategy is used the
evaluator will consider its appropriateness for adequately testing the
interfaces. Specifically the evaluator determines whether testing at the
internal interfaces is necessary or whether these internal interfaces can be
adequately tested (albeit implicitly) by exercising the external interfaces.
This determination is left to the evaluator, as is its justification.
ATE_DPT.3.2C
The analysis of the depth of testing shall demonstrate that all TSF
subsystems in the TOE design have been tested.
ATE_DPT.3-6
The evaluator shall examine the test procedures to determine that all
descriptions of TSF subsystem behaviour and interaction are tested.
1306
This work unit verifies the completeness of work unit ATE_DPT.3-1. All
descriptions of TSF subsystem behaviour and of interactions among TSF
subsystems that are provided in the TOE design have to be tested.
Incomplete depth of testing would be evident if a description of TSF
subsystem behaviour or of interactions among TSF subsystems was
identified in the TOE design and no tests could be attributed to it.
1307
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to component interfaces in the TOE design.
ATE_DPT.3.3C
The analysis of the depth of testing shall demonstrate that all modules in
the TOE design have been tested.
ATE_DPT.3-7
The evaluator shall examine the test procedures to determine that all
interfaces of all modules are tested.
1308
This work unit verifies the completeness of work unit ATE_DPT.3-4. All
interfaces of TSF modules that are provided in the TOE design have to be
tested. Incomplete depth of testing would be evident if any interface of any
TSF module was identified in the TOE design and no tests could be
attributed to it.
1309
The evaluator is reminded that this does not imply that all tests in the test
documentation must map to an interface of a TSF module in the TOE design.
14.4.4
Evaluation of sub-activity (ATE_DPT.4)
1310
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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14.5
Functional tests (ATE_FUN)
14.5.1
Evaluation of sub-activity (ATE_FUN.1)
14.5.1.1
Objectives
1311
The objective of this sub-activity is to determine whether the developer
correctly performed and documented the tests in the test documentation.
14.5.1.2
Input
1312
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the test documentation.
14.5.1.3
Application notes
1313
The extent to which the test documentation is required to cover the TSF is
dependent upon the coverage assurance component.
1314
For the developer tests provided, the evaluator determines whether the tests
are repeatable, and the extent to which the developer's tests can be used for
the evaluator's independent testing effort. Any TSFI for which the
developer's test results indicate that it might not perform as specified should
be tested independently by the evaluator to determine whether or not it does.
14.5.1.4
Action ATE_FUN.1.1E
ATE_FUN.1.1C
The test documentation shall consist of test plans, expected test results and
actual test results.
ATE_FUN.1-1
The evaluator shall check that the test documentation includes test plans,
expected test results and actual test results.
1315
The evaluator checks that test plans, expected tests results and actual test
results are included in the test documentation.
ATE_FUN.1.2C
The test plans shall identify the tests to be performed and describe the
scenarios for performing each test. These scenarios shall include any
ordering dependencies on the results of other tests.
ATE_FUN.1-2
The evaluator shall examine the test plan to determine that it describes the
scenarios for performing each test.
1316
The evaluator determines that the test plan provides information about the
test configuration being used: both on the configuration of the TOE and on
any test equipment being used. This information should be detailed enough
to ensure that the test configuration is reproducible.
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1317
The evaluator also determines that the test plan provides information about
how to execute the test: any necessary automated set-up procedures (and
whether they require privilege to run), inputs to be applied, how these inputs
are applied, how output is obtained, any automated clean-up procedures (and
whether they require privilege to run), etc. This information should be
detailed enough to ensure that the test is reproducible.
1318
The evaluator may wish to employ a sampling strategy when performing this
work unit.
ATE_FUN.1-3
The evaluator shall examine the test plan to determine that the TOE test
configuration is consistent with the ST.
1319
The TOE referred to in the developer's test plan should have the same unique
reference as established by the CM capabilities (ALC_CMC) sub-activities
and identified in the ST introduction.
1320
It is possible for the ST to specify more than one configuration for
evaluation. The evaluator verifies that all test configurations identified in the
developer test documentation are consistent with the ST. For example, the
ST might define configuration options that must be set, which could have an
impact upon what constitutes the TOE by including or excluding additional
portions. The evaluator verifies that all such variations of the TOE are
considered.
1321
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment.
There may be some objectives for the operational environment that do not
apply to the test environment. For example, an objective about user
clearances may not apply; however, an objective about a single point of
connection to a network would apply.
1322
The evaluator may wish to employ a sampling strategy when performing this
work unit.
1323
If this work unit is applied to a component TOE that might be
used/integrated in a composed TOE (see Class ACO: Composition), the
following will apply. In the instances that the component TOE under
evaluation depends on other components in the operational environment to
support their operation, the developer may wish to consider using the other
component(s) that will be used in the composed TOE to fulfil the
requirements of the operational environment as one of the test
configurations. This will reduce the amount an additional testing that will be
required for the composed TOE evaluation.
ATE_FUN.1-4
The evaluator shall examine the test plans to determine that sufficient
instructions are provided for any ordering dependencies.
1324
Some steps may have to be performed to establish initial conditions. For
example, user accounts need to be added before they can be deleted. An
example of ordering dependencies on the results of other tests is the need to
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perform actions in a test that will result in the generation of audit records,
before performing a test to consider the searching and sorting of those audit
records. Another example of an ordering dependency would be where one
test case generates a file of data to be used as input for another test case.
1325
The evaluator may wish to employ a sampling strategy when performing this
work unit.
ATE_FUN.1.3C
The expected test results shall show the anticipated outputs from a
successful execution of the tests.
ATE_FUN.1-5
The evaluator shall examine the test documentation to determine that all
expected tests results are included.
1326
The expected test results are needed to determine whether or not a test has
been successfully performed. Expected test results are sufficient if they are
unambiguous and consistent with expected behaviour given the testing
approach.
1327
The evaluator may wish to employ a sampling strategy when performing this
work unit.
ATE_FUN.1.4C
The actual test results shall be consistent with the expected test results.
ATE_FUN.1-6
The evaluator shall check that the actual test results in the test
documentation are consistent with the expected test results in the test
documentation.
1328
A comparison of the actual and expected test results provided by the
developer will reveal any inconsistencies between the results. It may be that
a direct comparison of actual results cannot be made until some data
reduction or synthesis has been first performed. In such cases, the
developer's test documentation should describe the process to reduce or
synthesise the actual data.
1329
For example, the developer may need to test the contents of a message buffer
after a network connection has occurred to determine the contents of the
buffer. The message buffer will contain a binary number. This binary number
would have to be converted to another form of data representation in order to
make the test more meaningful. The conversion of this binary representation
of data into a higher-level representation will have to be described by the
developer in enough detail to allow an evaluator to perform the conversion
process (i.e. synchronous or asynchronous transmission, number of stop bits,
parity, etc.).
1330
It should be noted that the description of the process used to reduce or
synthesise the actual data is used by the evaluator not to actually perform the
necessary modification but to assess whether this process is correct. It is up
to the developer to transform the expected test results into a format that
allows an easy comparison with the actual test results.
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1331
The evaluator may wish to employ a sampling strategy when performing this
work unit.
ATE_FUN.1-7
The evaluator shall report the developer testing effort, outlining the testing
approach, configuration, depth and results.
1332
The developer testing information recorded in the ETR allows the evaluator
to convey the overall testing approach and effort expended on the testing of
the TOE by the developer. The intent of providing this information is to give
a meaningful overview of the developer testing effort. It is not intended that
the information regarding developer testing in the ETR be an exact
reproduction of specific test steps or results of individual tests. The intention
is to provide enough detail to allow other evaluators and overseers to gain
some insight about the developer's testing approach, amount of testing
performed, TOE test configurations, and the overall results of the developer
testing.
1333
Information that would typically be found in the ETR section regarding the
developer testing effort is:
a)
TOE test configurations. The particular configurations of the TOE
that were tested, including whether any privileged code was required
to set up the test or clean up afterwards;
b)
testing approach. An account of the overall developer testing strategy
employed;
c)
testing results. A description of the overall developer testing results.
1334
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the developer testing effort.
14.5.2
Evaluation of sub-activity (ATE_FUN.2)
1335
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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14.6
Independent testing (ATE_IND)
14.6.1
Evaluation of sub-activity (ATE_IND.1)
14.6.1.1
Objectives
1336
The goal of this activity is to determine, by independently testing a subset of
the TSFI, whether the TOE behaves as specified in the functional
specification and guidance documentation.
14.6.1.2
Input
1337
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the operational user guidance;
d)
the preparative user guidance;
e)
the TOE suitable for testing.
14.6.1.3
Action ATE_IND.1.1E
ATE_IND.1.1C
The TOE shall be suitable for testing.
ATE_IND.1-1
The evaluator shall examine the TOE to determine that the test configuration
is consistent with the configuration under evaluation as specified in the ST.
1338
The TOE provided by the developer should have the same unique reference
as established by the CM capabilities (ALC_CMC) sub-activities and
identified in the ST introduction.
1339
It is possible for the ST to specify more than one configuration for
evaluation. The TOE may comprise a number of distinct hardware and
software entities that need to be tested in accordance with the ST. The
evaluator verifies that all test configurations are consistent with the ST.
1340
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment and
ensure they are met in the testing environment. There may be some
objectives for the operational environment that do not apply to the test
environment. For example, an objective about user clearances may not apply;
however, an objective about a single point of connection to a network would
apply.
1341
If any test resources are used (e.g. meters, analysers) it will be the evaluator's
responsibility to ensure that these resources are calibrated correctly.
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ATE_IND.1-2
The evaluator shall examine the TOE to determine that it has been installed
properly and is in a known state.
1342
It is possible for the evaluator to determine the state of the TOE in a number
of ways. For example, previous successful completion of the Evaluation of
sub-activity (AGD_PRE.1) sub-activity will satisfy this work unit if the
evaluator still has confidence that the TOE being used for testing was
installed properly and is in a known state. If this is not the case, then the
evaluator should follow the developer's procedures to install and start up the
TOE, using the supplied guidance only.
1343
If the evaluator has to perform the installation procedures because the TOE is
in an unknown state, this work unit when successfully completed could
satisfy work unit AGD_PRE.1-5.
14.6.1.4
Action ATE_IND.1.2E
ATE_IND.1-3
The evaluator shall devise a test subset.
1344
The evaluator selects a test subset and testing strategy that is appropriate for
the TOE. One extreme testing strategy would be to have the test subset
contain as many interfaces as possible tested with little rigour. Another
testing strategy would be to have the test subset contain a few interfaces
based on their perceived relevance and rigorously test these interfaces.
1345
Typically the testing approach taken by the evaluator should fall somewhere
between these two extremes. The evaluator should exercise most of the
interfaces using at least one test, but testing need not demonstrate exhaustive
specification testing.
1346
The evaluator, when selecting the subset of the interfaces to be tested, should
consider the following factors:
1347
a)
The number of interfaces from which to draw upon for the test subset.
Where the TSF includes only a small number of relatively simple
interfaces, it may be practical to rigorously test all of the interfaces.
In other cases this may not be cost-effective, and sampling is
required.
b)
Maintaining a balance of evaluation activities. The evaluator effort
expended on the test activity should be commensurate with that
expended on any other evaluation activity.
The evaluator selects the interfaces to compose the subset. This selection will
depend on a number of factors, and consideration of these factors may also
influence the choice of test subset size:
a)
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Significance of interfaces. Those interfaces more significant than
others should be included in the test subset. One major factor of
“significance” is the security-relevance (SFR-enforcing interfaces
would be more significant than SFR-supporting interfaces, which are
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more significant than SFR-non-interfering interfaces; see CC Part 3
Section Functional specification (ADV_FSP)). The other major factor
of “significance” is the number of SFRs mapping to this interface (as
determined when identifying the correspondence between levels of
abstraction in ADV).
b)
Complexity of the interface. Complex interfaces may require
complex tests that impose onerous requirements on the developer or
evaluator, which may not be conducive to cost-effective evaluations.
Conversely, they are a likely area to find errors and are good
candidates for the subset. The evaluator will need to strike a balance
between these considerations.
c)
Implicit testing. Testing some interfaces may often implicitly test
other interfaces, and their inclusion in the subset may maximise the
number of interfaces tested (albeit implicitly). Certain interfaces will
typically be used to provide a variety of security functionality, and
will tend to be the target of an effective testing approach.
d)
Types of interfaces (e.g. programmatic, command-line, protocol).
The evaluator should consider including tests for all different types of
interfaces that the TOE supports.
e)
Interfaces that give rise to features that are innovative or unusual.
Where the TOE contains innovative or unusual features, which may
feature strongly in marketing literature and guidance documents, the
corresponding interfaces should be strong candidates for testing.
1348
This guidance articulates factors to consider during the selection process of
an appropriate test subset, but these are by no means exhaustive.
ATE_IND.1-4
The evaluator shall produce test documentation for the test subset that is
sufficiently detailed to enable the tests to be reproducible.
1349
With an understanding of the expected behaviour of the TSF, from the ST
and the functional specification, the evaluator has to determine the most
feasible way to test the interface. Specifically the evaluator considers:
a)
the approach that will be used, for instance, whether an external
interface will be tested, or an internal interface using a test harness, or
will an alternate test approach be employed (e.g. in exceptional
circumstances, a code inspection, if the implementation
representation is available);
b)
the interface(s) that will be used to test and observe responses;
c)
the initial conditions that will need to exist for the test (i.e. any
particular objects or subjects that will need to exist and security
attributes they will need to have);
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d)
special test equipment that will be required to either stimulate an
interface (e.g. packet generators) or make observations of an interface
(e.g. network analysers).
1350
The evaluator may find it practical to test each interface using a series of test
cases, where each test case will test a very specific aspect of expected
behaviour.
1351
The evaluator's test documentation should specify the derivation of each test,
tracing it back to the relevant interface(s).
ATE_IND.1-5
The evaluator shall conduct testing.
1352
The evaluator uses the test documentation developed as a basis for executing
tests on the TOE. The test documentation is used as a basis for testing but
this does not preclude the evaluator from performing additional ad hoc tests.
The evaluator may devise new tests based on behaviour of the TOE
discovered during testing. These new tests are recorded in the test
documentation.
ATE_IND.1-6
The evaluator shall record the following information about the tests that
compose the test subset:
a)
identification of the interface behaviour to be tested;
b)
instructions to connect and setup all required test equipment as
required to conduct the test;
c)
instructions to establish all prerequisite test conditions;
d)
instructions to stimulate the interface;
e)
instructions for observing the behaviour of the interface;
f)
descriptions of all expected results and the necessary analysis to be
performed on the observed behaviour for comparison against
expected results;
g)
instructions to conclude the test and establish the necessary post-test
state for the TOE;
h)
actual test results.
1353
The level of detail should be such that another evaluator could repeat the
tests and obtain an equivalent result. While some specific details of the test
results may be different (e.g. time and date fields in an audit record) the
overall result should be identical.
1354
There may be instances when it is unnecessary to provide all the information
presented in this work unit (e.g. the actual test results of a test may not
require any analysis before a comparison between the expected results can be
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made). The determination to omit this information is left to the evaluator, as
is the justification.
ATE_IND.1-7
The evaluator shall check that all actual test results are consistent with the
expected test results.
1355
Any differences in the actual and expected test results may indicate that the
TOE does not perform as specified or that the evaluator test documentation
may be incorrect. Unexpected actual results may require corrective
maintenance to the TOE or test documentation and perhaps require rerunning of impacted tests and modifying the test sample size and
composition. This determination is left to the evaluator, as is its justification.
ATE_IND.1-8
The evaluator shall report in the ETR the evaluator testing effort, outlining
the testing approach, configuration, depth and results.
1356
The evaluator testing information reported in the ETR allows the evaluator to
convey the overall testing approach and effort expended on the testing
activity during the evaluation. The intent of providing this information is to
give a meaningful overview of the testing effort. It is not intended that the
information regarding testing in the ETR be an exact reproduction of specific
test instructions or results of individual tests. The intention is to provide
enough detail to allow other evaluators and overseers to gain some insight
about the testing approach chosen, amount of testing performed, TOE test
configurations, and the overall results of the testing activity.
1357
Information that would typically be found in the ETR section regarding the
evaluator testing effort is:
1358
a)
TOE test configurations. The particular configurations of the TOE
that were tested;
b)
subset size chosen. The amount of interfaces that were tested during
the evaluation and a justification for the size;
c)
selection criteria for the interfaces that compose the subset. Brief
statements about the factors considered when selecting interfaces for
inclusion in the subset;
d)
interfaces tested. A brief listing of the interfaces that merited
inclusion in the subset;
e)
verdict for the activity. The overall judgement on the results of
testing during the evaluation.
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the testing the evaluator performed during the evaluation.
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14.6.2
Evaluation of sub-activity (ATE_IND.2)
14.6.2.1
Objectives
1359
The goal of this activity is to determine, by independently testing a subset of
the TSF, whether the TOE behaves as specified in the design documentation,
and to gain confidence in the developer's test results by performing a sample
of the developer's tests.
14.6.2.2
Input
1360
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the TOE design description;
d)
the operational user guidance;
e)
the preparative user guidance;
f)
the configuration management documentation;
g)
the test documentation;
h)
the TOE suitable for testing.
14.6.2.3
Action ATE_IND.2.1E
ATE_IND.2.1C
The TOE shall be suitable for testing.
ATE_IND.2-1
The evaluator shall examine the TOE to determine that the test configuration
is consistent with the configuration under evaluation as specified in the ST.
1361
The TOE provided by the developer and identified in the test plan should
have the same unique reference as established by the CM capabilities
(ALC_CMC) sub-activities and identified in the ST introduction.
1362
It is possible for the ST to specify more than one configuration for
evaluation. The TOE may comprise a number of distinct hardware and
software entities that need to be tested in accordance with the ST. The
evaluator verifies that all test configurations are consistent with the ST.
1363
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment and
ensure they are met in the testing environment. There may be some
objectives for the operational environment that do not apply to the test
environment. For example, an objective about user clearances may not apply;
however, an objective about a single point of connection to a network would
apply.
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1364
If any test resources are used (e.g. meters, analysers) it will be the evaluator's
responsibility to ensure that these resources are calibrated correctly.
ATE_IND.2-2
The evaluator shall examine the TOE to determine that it has been installed
properly and is in a known state
1365
It is possible for the evaluator to determine the state of the TOE in a number
of ways. For example, previous successful completion of the Evaluation of
sub-activity (AGD_PRE.1) sub-activity will satisfy this work unit if the
evaluator still has confidence that the TOE being used for testing was
installed properly and is in a known state. If this is not the case, then the
evaluator should follow the developer's procedures to install and start up the
TOE, using the supplied guidance only.
1366
If the evaluator has to perform the installation procedures because the TOE is
in an unknown state, this work unit when successfully completed could
satisfy work unit AGD_PRE.1-5.
ATE_IND.2.2C
The developer shall provide an equivalent set of resources to those that
were used in the developer's functional testing of the TSF.
ATE_IND.2-3
The evaluator shall examine the set of resources provided by the developer
to determine that they are equivalent to the set of resources used by the
developer to functionally test the TSF
1367
The set of resource used by the developer is documented in the developer test
plan, as considered in the Functional tests (ATE_FUN) family. The resource
set may include laboratory access and special test equipment, among others.
Resources that are not identical to those used by the developer need to be
equivalent in terms of any impact they may have on test results.
14.6.2.4
Action ATE_IND.2.2E
ATE_IND.2-4
The evaluator shall conduct testing using a sample of tests found in the
developer test plan and procedures.
1368
The overall aim of this work unit is to perform a sufficient number of the
developer tests to confirm the validity of the developer's test results. The
evaluator has to decide on the size of the sample, and the developer tests that
will compose the sample (see A.2).
1369
All the developer tests can be traced back to specific interfaces. Therefore,
the factors to consider in the selection of the tests to compose the sample are
similar to those listed for subset selection in work-unit ATE_IND.2-6.
Additionally, the evaluator may wish to employ a random sampling method
to select developer tests to include in the sample.
ATE_IND.2-5
The evaluator shall check that all the actual test results are consistent with
the expected test results.
1370
Inconsistencies between the developer's expected test results and actual test
results will compel the evaluator to resolve the discrepancies. Inconsistencies
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encountered by the evaluator could be resolved by a valid explanation and
resolution of the inconsistencies by the developer.
1371
If a satisfactory explanation or resolution can not be reached, the evaluator's
confidence in the developer's test results may be lessened and it may be
necessary for the evaluator to increase the sample size to the extent that the
subset identified in work unit ATE_IND.2-4 is adequately tested:
deficiencies with the developer's tests need to result in either corrective
action to the developer's tests or in the production of new tests by the
evaluator.
14.6.2.5
Action ATE_IND.2.3E
ATE_IND.2-6
The evaluator shall devise a test subset.
1372
The evaluator selects a test subset and testing strategy that is appropriate for
the TOE. One extreme testing strategy would be to have the test subset
contain as many interfaces as possible tested with little rigour. Another
testing strategy would be to have the test subset contain a few interfaces
based on their perceived relevance and rigorously test these interfaces.
1373
Typically the testing approach taken by the evaluator should fall somewhere
between these two extremes. The evaluator should exercise most of the
interfaces using at least one test, but testing need not demonstrate exhaustive
specification testing.
1374
The evaluator, when selecting the subset of the interfaces to be tested, should
consider the following factors:
a)
b)
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The developer test evidence. The developer test evidence consists of:
the test documentation, the available test coverage analysis, and the
available depth of testing analysis. The developer test evidence will
provide insight as to how the TSF has been exercised by the
developer during testing. The evaluator applies this information when
developing new tests to independently test the TOE. Specifically the
evaluator should consider:
1)
augmentation of developer testing for interfaces. The
evaluator may wish to perform more of the same type of tests
by varying parameters to more rigorously test the interface.
2)
supplementation of developer testing strategy for interfaces.
The evaluator may wish to vary the testing approach of a
specific interface by testing it using another test strategy.
The number of interfaces from which to draw upon for the test subset.
Where the TSF includes only a small number of relatively simple
interfaces, it may be practical to rigorously test all of them. In other
cases this may not be cost-effective, and sampling is required.
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c)
1375
1376
Maintaining a balance of evaluation activities. The evaluator effort
expended on the test activity should be commensurate with that
expended on any other evaluation activity.
The evaluator selects the interfaces to compose the subset. This selection will
depend on a number of factors, and consideration of these factors may also
influence the choice of test subset size:
a)
Rigour of developer testing of the interfaces. Those interfaces that the
evaluator determines require additional testing should be included in
the test subset.
b)
Developer test results. If the results of developer tests cause the
evaluator to doubt that an interface is not properly implemented, then
the evaluator should include such interfaces in the test subset.
c)
Significance of interfaces. Those interfaces more significant than
others should be included in the test subset. One major factor of
“significance” is the security-relevance (SFR-enforcing interfaces
would be more significant than SFR-supporting interfaces, which are
more significant than SFR-non-interfering interfaces; see CC Part 3
Section ADV_FSP). The other major factor of “significance” is the
number of SFRs mapping to this interface (as determined when
identifying the correspondence between levels of abstraction in
ADV).
d)
Complexity of interfaces. Interfaces that require complex
implementation may require complex tests that impose onerous
requirements on the developer or evaluator, which may not be
conducive to cost-effective evaluations. Conversely, they are a likely
area to find errors and are good candidates for the subset. The
evaluator will need to strike a balance between these considerations.
e)
Implicit testing. Testing some interfaces may often implicitly test
other interfaces, and their inclusion in the subset may maximise the
number of interfaces tested (albeit implicitly). Certain interfaces will
typically be used to provide a variety of security functionality, and
will tend to be the target of an effective testing approach.
f)
Types of interfaces (e.g. programmatic, command-line, protocol).
The evaluator should consider including tests for all different types of
interfaces that the TOE supports.
g)
Interfaces that give rise to features that are innovative or unusual.
Where the TOE contains innovative or unusual features, which may
feature strongly in marketing literature and guidance documents, the
corresponding interfaces should be strong candidates for testing.
This guidance articulates factors to consider during the selection process of
an appropriate test subset, but these are by no means exhaustive.
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ATE_IND.2-7
The evaluator shall produce test documentation for the test subset that is
sufficiently detailed to enable the tests to be reproducible.
1377
With an understanding of the expected behaviour of the TSF, from the ST,
the functional specification, and the TOE design description, the evaluator
has to determine the most feasible way to test the interface. Specifically the
evaluator considers:
a)
the approach that will be used, for instance, whether an external
interface will be tested, or an internal interface using a test harness, or
will an alternate test approach be employed (e.g. in exceptional
circumstances, a code inspection);
b)
the interface(s) that will be used to test and observe responses;
c)
the initial conditions that will need to exist for the test (i.e. any
particular objects or subjects that will need to exist and security
attributes they will need to have);
d)
special test equipment that will be required to either stimulate an
interface (e.g. packet generators) or make observations of an interface
(e.g. network analysers).
1378
The evaluator may find it practical to test each interface using a series of test
cases, where each test case will test a very specific aspect of expected
behaviour of that interface.
1379
The evaluator's test documentation should specify the derivation of each test,
tracing it back to the relevant interface(s).
ATE_IND.2-8
The evaluator shall conduct testing.
1380
The evaluator uses the test documentation developed as a basis for executing
tests on the TOE. The test documentation is used as a basis for testing but
this does not preclude the evaluator from performing additional ad hoc tests.
The evaluator may devise new tests based on behaviour of the TOE
discovered during testing. These new tests are recorded in the test
documentation.
ATE_IND.2-9
The evaluator shall record the following information about the tests that
compose the test subset:
a)
identification of the interface behaviour to be tested;
b)
instructions to connect and setup all required test equipment as
required to conduct the test;
c)
instructions to establish all prerequisite test conditions;
d)
instructions to stimulate the interface;
e)
instructions for observing the interface;
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f)
descriptions of all expected results and the necessary analysis to be
performed on the observed behaviour for comparison against
expected results;
g)
instructions to conclude the test and establish the necessary post-test
state for the TOE;
h)
actual test results.
1381
The level of detail should be such that another evaluator could repeat the
tests and obtain an equivalent result. While some specific details of the test
results may be different (e.g. time and date fields in an audit record) the
overall result should be identical.
1382
There may be instances when it is unnecessary to provide all the information
presented in this work unit (e.g. the actual test results of a test may not
require any analysis before a comparison between the expected results can be
made). The determination to omit this information is left to the evaluator, as
is the justification.
ATE_IND.2-10
The evaluator shall check that all actual test results are consistent with the
expected test results.
1383
Any differences in the actual and expected test results may indicate that the
TOE does not perform as specified or that the evaluator test documentation
may be incorrect. Unexpected actual results may require corrective
maintenance to the TOE or test documentation and perhaps require rerunning of impacted tests and modifying the test sample size and
composition. This determination is left to the evaluator, as is its justification.
ATE_IND.2-11
The evaluator shall report in the ETR the evaluator testing effort, outlining
the testing approach, configuration, depth and results.
1384
The evaluator testing information reported in the ETR allows the evaluator to
convey the overall testing approach and effort expended on the testing
activity during the evaluation. The intent of providing this information is to
give a meaningful overview of the testing effort. It is not intended that the
information regarding testing in the ETR be an exact reproduction of specific
test instructions or results of individual tests. The intention is to provide
enough detail to allow other evaluators and overseers to gain some insight
about the testing approach chosen, amount of evaluator testing performed,
amount of developer tests performed, TOE test configurations, and the
overall results of the testing activity.
1385
Information that would typically be found in the ETR section regarding the
evaluator testing effort is:
a)
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TOE test configurations. The particular configurations of the TOE
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b)
subset size chosen. The amount of interfaces that were tested during
the evaluation and a justification for the size.
c)
selection criteria for the interfaces that compose the subset. Brief
statements about the factors considered when selecting interfaces for
inclusion in the subset.
d)
Interfaces tested. A brief listing of the interfaces that merited
inclusion in the subset.
e)
developer tests performed. The amount of developer tests performed
and a brief description of the criteria used to select the tests.
f)
verdict for the activity. The overall judgement on the results of
testing during the evaluation.
1386
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the testing the evaluator performed during the evaluation.
14.6.3
Evaluation of sub-activity (ATE_IND.3)
1387
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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15
Class AVA: Vulnerability assessment
15.1
Introduction
1388
The purpose of the vulnerability assessment activity is to determine the
exploitability of flaws or weaknesses in the TOE in the operational
environment. This determination is based upon analysis of the evaluation
evidence and a search of publicly available material by the evaluator and is
supported by evaluator penetration testing.
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15.2
Vulnerability analysis (AVA_VAN)
15.2.1
Evaluation of sub-activity (AVA_VAN.1)
15.2.1.1
Objectives
1389
The objective of this sub-activity is to determine whether the TOE, in its
operational environment, has easily identifiable exploitable vulnerabilities.
15.2.1.2
Input
1390
The evaluation evidence for this sub-activity is:
1391
a)
the ST;
b)
the guidance documentation;
c)
the TOE suitable for testing;
d)
information publicly available to support the identification of
potential vulnerabilities.
Other input for this sub-activity is:
a)
current information regarding potential vulnerabilities (e.g. from an
evaluation authority).
15.2.1.3
Application notes
1392
The evaluator should consider performing additional tests as a result of
potential vulnerabilities encountered during the conduct of other parts of the
evaluation.
1393
The use of the term guidance in this sub-activity refers to the operational
guidance and the preparative guidance.
1394
Potential vulnerabilities may be in information that is publicly available, or
not, and may require skill to exploit, or not. These two aspects are related,
but are distinct. It should not be assumed that, simply because a potential
vulnerability is identifiable from information that is publicly available, it can
be easily exploited.
15.2.1.4
Action AVA_VAN.1.1E
AVA_VAN.1.1C
The TOE shall be suitable for testing.
AVA_VAN.1-1
The evaluator shall examine the TOE to determine that the test configuration
is consistent with the configuration under evaluation as specified in the ST.
1395
The TOE provided by the developer and identified in the test plan should
have the same unique reference as established by the CM capabilities
(ALC_CMC) sub-activities and identified in the ST introduction.
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1396
It is possible for the ST to specify more than one configuration for
evaluation. The TOE may comprise a number of distinct hardware and
software entities that need to be tested in accordance with the ST. The
evaluator verifies that all test configurations are consistent with the ST.
1397
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment and
ensure they are met in the testing environment. There may be some
objectives for the operational environment that do not apply to the test
environment. For example, an objective about user clearances may not apply;
however, an objective about a single point of connection to a network would
apply.
1398
If any test resources are used (e.g. meters, analysers) it will be the evaluator's
responsibility to ensure that these resources are calibrated correctly.
AVA_VAN.1-2
The evaluator shall examine the TOE to determine that it has been installed
properly and is in a known state
1399
It is possible for the evaluator to determine the state of the TOE in a number
of ways. For example, previous successful completion of the Evaluation of
sub-activity (AGD_PRE.1) sub-activity will satisfy this work unit if the
evaluator still has confidence that the TOE being used for testing was
installed properly and is in a known state. If this is not the case, then the
evaluator should follow the developer's procedures to install and start up the
TOE, using the supplied guidance only.
1400
If the evaluator has to perform the installation procedures because the TOE is
in an unknown state, this work unit when successfully completed could
satisfy work unit AGD_PRE.1-5.
15.2.1.5
Action AVA_VAN.1.2E
AVA_VAN.1-3
The evaluator shall examine sources of information publicly available to
identify potential vulnerabilities in the TOE.
1401
The evaluator examines the sources of information publicly available to
support the identification of possible potential vulnerabilities in the TOE.
There are many sources of publicly available information, which should be
considered, e.g. mailing lists and security forums on the world wide web that
report known vulnerabilities in specified technologies.
1402
The evaluator should not constrain their consideration of publicly available
information to the above, but should consider any other relevant information
available.
1403
While examining the evidence provided the evaluator will use the
information in the public domain to further search for potential
vulnerabilities. Where the evaluators have identified areas of concern, the
evaluator should consider information publicly available that relate to those
areas of concern.
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1404
The availability of information that may be readily available to an attacker
that helps to identify and facilitate attacks effectively operates to
substantially enhance the attack potential of a given attacker. The
accessibility of vulnerability information and sophisticated attack tools on
the Internet makes it more likely that this information will be used in
attempts to identify potential vulnerabilities in the TOE and exploit them.
Modern search tools make such information easily available to the evaluator,
and the determination of resistance to published potential vulnerabilities and
well known generic attacks can be achieved in a cost-effective manner.
1405
The search of the information publicly available should be focused on those
sources that refer specifically to the product from which the TOE is derived.
The extensiveness of this search should consider the following factors: TOE
type, evaluator experience in this TOE type, expected attack potential and the
level of ADV evidence available.
1406
The identification process is iterative, where the identification of one
potential vulnerability may lead to identifying another area of concern that
requires further investigation.
1407
The evaluator will report what actions were taken to identify potential
vulnerabilities in the information publicly available. However, in this type of
search, the evaluator may not be able to describe the steps in identifying
potential vulnerabilities before the outset of the examination, as the approach
may evolve as a result of findings during the search.
1408
The evaluator will report the evidence examined in completing the search for
potential vulnerabilities.
AVA_VAN.1-4
The evaluator shall record in the ETR the identified potential vulnerabilities
that are candidates for testing and applicable to the TOE in its operational
environment.
1409
It may be identified that no further consideration of the potential
vulnerability is required if for example the evaluator identifies that measures
in the operational environment, either IT or non-IT, prevent exploitation of
the potential vulnerability in that operational environment. For instance,
restricting physical access to the TOE to authorised users only may
effectively render a potential vulnerability to tampering unexploitable.
1410
The evaluator records any reasons for exclusion of potential vulnerabilities
from further consideration if the evaluator determines that the potential
vulnerability is not applicable in the operational environment. Otherwise the
evaluator records the potential vulnerability for further consideration.
1411
A list of potential vulnerabilities applicable to the TOE in its operational
environment, which can be used as an input into penetration testing
activities, shall be reported in the ETR by the evaluators.
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15.2.1.6
Action AVA_VAN.1.3E
AVA_VAN.1-5
The evaluator shall devise penetration tests, based on the independent search
for potential vulnerabilities.
1412
The evaluator prepares for penetration testing as necessary to determine the
susceptibility of the TOE, in its operational environment, to the potential
vulnerabilities identified during the search of the sources of information
publicly available. The evaluator should have access to current information
(e.g. from the evaluation authority) regarding known potential vulnerabilities
that may not have been considered by the evaluator, and may also have
encountered potential vulnerabilities as a result of performing other
evaluation activities.
1413
The evaluator will probably find it practical to carry out penetration test
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1414
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required a Basic attack
potential. In some cases, however, it will be necessary to carry out a test
before the exploitability can be determined. Where, as a result of evaluation
expertise, the evaluator discovers a potential vulnerability that is beyond
Basic attack potential, this is reported in the ETR as a residual vulnerability.
AVA_VAN.1-6
The evaluator shall produce penetration test documentation for the tests
based on the list of potential vulnerabilities in sufficient detail to enable the
tests to be repeatable. The test documentation shall include:
1415
a)
identification of the potential vulnerability the TOE is being tested
for;
b)
instructions to connect and setup all required test equipment as
required to conduct the penetration test;
c)
instructions to establish all penetration test prerequisite initial
conditions;
d)
instructions to stimulate the TSF;
e)
instructions for observing the behaviour of the TSF;
f)
descriptions of all expected results and the necessary analysis to be
performed on the observed behaviour for comparison against
expected results;
g)
instructions to conclude the test and establish the necessary post-test
state for the TOE.
The evaluator prepares for penetration testing based on the list of potential
vulnerabilities identified during the search of the public domain.
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1416
The evaluator is not expected to determine the exploitability for potential
vulnerabilities beyond those for which a Basic attack potential is required to
effect an attack. However, as a result of evaluation expertise, the evaluator
may discover a potential vulnerability that is exploitable only by an attacker
with greater than Basic attack potential. Such vulnerabilities are to be
reported in the ETR as residual vulnerabilities.
1417
With an understanding of the potential vulnerability, the evaluator
determines the most feasible way to test for the TOE's susceptibility.
Specifically the evaluator considers:
a)
the TSFI or other TOE interface that will be used to stimulate the
TSF and observe responses;
b)
initial conditions that will need to exist for the test (i.e. any particular
objects or subjects that will need to exist and security attributes they
will need to have);
c)
special test equipment that will be required to either stimulate a TSFI
or make observations of a TSFI (although it is unlikely that specialist
equipment would be required to exploit a potential vulnerability
assuming a Basic attack potential);
d)
whether theoretical analysis should replace physical testing,
particularly relevant where the results of an initial test can be
extrapolated to demonstrate that repeated attempts of an attack are
likely to succeed after a given number of attempts.
1418
The evaluator will probably find it practical to carry out penetration testing
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1419
The intent of specifying this level of detail in the test documentation is to
allow another evaluator to repeat the tests and obtain an equivalent result.
AVA_VAN.1-7
The evaluator shall conduct penetration testing.
1420
The evaluator uses the penetration test documentation resulting from work
unit AVA_VAN.1-5 as a basis for executing penetration tests on the TOE,
but this does not preclude the evaluator from performing additional ad hoc
penetration tests. If required, the evaluator may devise ad hoc tests as a result
of information learnt during penetration testing that, if performed by the
evaluator, are to be recorded in the penetration test documentation. Such tests
may be required to follow up unexpected results or observations, or to
investigate potential vulnerabilities suggested to the evaluator during the preplanned testing.
1421
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required a Basic attack
potential. In some cases, however, it will be necessary to carry out a test
before the exploitability can be determined. Where, as a result of evaluation
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expertise, the evaluator discovers a potential vulnerability that is beyond
Basic attack potential, this is reported in the ETR as a residual vulnerability.
AVA_VAN.1-8
The evaluator shall record the actual results of the penetration tests.
1422
While some specific details of the actual test results may be different from
those expected (e.g. time and date fields in an audit record) the overall result
should be identical. Any unexpected test results should be investigated. The
impact on the evaluation should be stated and justified.
AVA_VAN.1-9
The evaluator shall report in the ETR the evaluator penetration testing effort,
outlining the testing approach, configuration, depth and results.
1423
The penetration testing information reported in the ETR allows the evaluator
to convey the overall penetration testing approach and effort expended on
this sub-activity. The intent of providing this information is to give a
meaningful overview of the evaluator's penetration testing effort. It is not
intended that the information regarding penetration testing in the ETR be an
exact reproduction of specific test steps or results of individual penetration
tests. The intention is to provide enough detail to allow other evaluators and
evaluation authorities to gain some insight about the penetration testing
approach chosen, amount of penetration testing performed, TOE test
configurations, and the overall results of the penetration testing activity.
1424
Information that would typically be found in the ETR section regarding
evaluator penetration testing efforts is:
a)
TOE test configurations. The particular configurations of the TOE
that were penetration tested;
b)
TSFI penetration tested. A brief listing of the TSFI and other TOE
interfaces that were the focus of the penetration testing;
c)
verdict for the sub-activity. The overall judgement on the results of
penetration testing.
1425
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the penetration testing the evaluator performed during the
evaluation.
AVA_VAN.1-10
The evaluator shall examine the results of all penetration testing to
determine that the TOE, in its operational environment, is resistant to an
attacker possessing a Basic attack potential.
1426
If the results reveal that the TOE, in its operational environment, has
vulnerabilities exploitable by an attacker possessing less than EnhancedBasic attack potential, then this evaluator action fails.
1427
The guidance in B.4 should be used to determine the attack potential required
to exploit a particular vulnerability and whether it can therefore be exploited
in the intended environment. It may not be necessary for the attack potential
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to be calculated in every instance, only if there is some doubt as to whether
or not the vulnerability can be exploited by an attacker possessing an attack
potential less than Enhanced-Basic.
AVA_VAN.1-11
The evaluator shall report in the ETR all exploitable vulnerabilities and
residual vulnerabilities, detailing for each:
a)
its source (e.g. CEM activity being undertaken when it was
conceived, known to the evaluator, read in a publication);
b)
the SFR(s) not met;
c)
a description;
d)
whether it is exploitable in its operational environment or not (i.e.
exploitable or residual).
e)
the amount of time, level of expertise, level of knowledge of the
TOE, level of opportunity and the equipment required to perform the
identified vulnerabilities, and the corresponding values using the
tables 3 and 4 of Annex B.4.
15.2.2
Evaluation of sub-activity (AVA_VAN.2)
15.2.2.1
Objectives
1428
The objective of this sub-activity is to determine whether the TOE, in its
operational environment, has vulnerabilities exploitable by attackers
possessing Basic attack potential.
15.2.2.2
Input
1429
The evaluation evidence for this sub-activity is:
1430
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the guidance documentation;
f)
the TOE suitable for testing;
g)
information publicly available to support the identification of
possible potential vulnerabilities.
The remaining implicit evaluation evidence for this sub-activity depends on
the components that have been included in the assurance package. The
evidence provided for each component is to be used as input in this subactivity.
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1431
Other input for this sub-activity is:
a)
current information regarding public domain potential vulnerabilities
and attacks (e.g. from an evaluation authority).
15.2.2.3
Application notes
1432
The evaluator should consider performing additional tests as a result of
potential vulnerabilities encountered during other parts of the evaluation.
15.2.2.4
Action AVA_VAN.2.1E
AVA_VAN.2.1C
The TOE shall be suitable for testing.
AVA_VAN.2-1
The evaluator shall examine the TOE to determine that the test configuration
is consistent with the configuration under evaluation as specified in the ST.
1433
The TOE provided by the developer and identified in the test plan should
have the same unique reference as established by the CM capabilities
(ALC_CMC) sub-activities and identified in the ST introduction.
1434
It is possible for the ST to specify more than one configuration for
evaluation. The TOE may comprise a number of distinct hardware and
software entities that need to be tested in accordance with the ST. The
evaluator verifies that all test configurations are consistent with the ST.
1435
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment and
ensure they are met in the testing environment. There may be some
objectives for the operational environment that do not apply to the test
environment. For example, an objective about user clearances may not apply;
however, an objective about a single point of connection to a network would
apply.
1436
If any test resources are used (e.g. meters, analysers) it will be the evaluator's
responsibility to ensure that these resources are calibrated correctly.
AVA_VAN.2-2
The evaluator shall examine the TOE to determine that it has been installed
properly and is in a known state
1437
It is possible for the evaluator to determine the state of the TOE in a number
of ways. For example, previous successful completion of the Evaluation of
sub-activity (AGD_PRE.1) sub-activity will satisfy this work unit if the
evaluator still has confidence that the TOE being used for testing was
installed properly and is in a known state. If this is not the case, then the
evaluator should follow the developer's procedures to install and start up the
TOE, using the supplied guidance only.
1438
If the evaluator has to perform the installation procedures because the TOE is
in an unknown state, this work unit when successfully completed could
satisfy work unit AGD_PRE.1-5.
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15.2.2.5
Action AVA_VAN.2.2E
AVA_VAN.2-3
The evaluator shall examine sources of information publicly available to
identify potential vulnerabilities in the TOE.
1439
The evaluator examines the sources of information publicly available to
support the identification of possible potential vulnerabilities in the TOE.
There are many sources of publicly available information which the
evaluator should consider using items such as those available on the world
wide web, including:
a)
specialist publications (magazines, books);
b)
research papers.
1440
The evaluator should not constrain their consideration of publicly available
information to the above, but should consider any other relevant information
available.
1441
While examining the evidence provided the evaluator will use the
information in the public domain to further search for potential
vulnerabilities. Where the evaluators have identified areas of concern, the
evaluator should consider information publicly available that relate to those
areas of concern.
1442
The availability of information that may be readily available to an attacker
that helps to identify and facilitate attacks may substantially enhance the
attack potential of a given attacker. The accessibility of vulnerability
information and sophisticated attack tools on the Internet makes it more
likely that this information will be used in attempts to identify potential
vulnerabilities in the TOE and exploit them. Modern search tools make such
information easily available to the evaluator, and the determination of
resistance to published potential vulnerabilities and well known generic
attacks can be achieved in a cost-effective manner.
1443
The search of the information publicly available should be focused on those
sources that refer specifically to the product from which the TOE is derived.
The extensiveness of this search should consider the following factors: TOE
type, evaluator experience in this TOE type, expected attack potential and the
level of ADV evidence available.
1444
The identification process is iterative, where the identification of one
potential vulnerability may lead to identifying another area of concern that
requires further investigation.
1445
The evaluator will report what actions were taken to identify potential
vulnerabilities in the evidence. However, in this type of search, the evaluator
may not be able to describe the steps in identifying potential vulnerabilities
before the outset of the examination, as the approach may evolve as a result
of findings during the search.
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1446
The evaluator will report the evidence examined in completing the search for
potential vulnerabilities. This selection of evidence may be derived from
those areas of concern identified by the evaluator, linked to the evidence the
attacker is assumed to be able to obtain, or according to another rationale
provided by the evaluator.
15.2.2.6
Action AVA_VAN.2.3E
AVA_VAN.2-4
The evaluator shall conduct a search of ST, guidance documentation,
functional specification, TOE design and security architecture description
evidence to identify possible potential vulnerabilities in the TOE.
1447
A search of the evidence should be completed whereby specifications and
documentation for the TOE are analysed and then potential vulnerabilities in
the TOE are hypothesised, or speculated. The list of hypothesised potential
vulnerabilities is then prioritised on the basis of the estimated probability that
a potential vulnerability exists and, assuming an exploitable vulnerability
does exist the attack potential required to exploit it, and on the extent of
control or compromise it would provide. The prioritised list of potential
vulnerabilities is used to direct penetration testing against the TOE.
1448
The security architecture description provides the developer vulnerability
analysis, as it documents how the TSF protects itself from interference from
untrusted subjects and prevents the bypass of security enforcement
functionality. Therefore, the evaluator should use this description of the
protection of the TSF as a basis for the search for possible ways to
undermine the TSF.
1449
Subject to the SFRs the TOE is to meet in the operational environment, the
evaluator's independent vulnerability analysis should consider generic
potential vulnerabilities under each of the following headings:
a)
generic potential vulnerabilities relevant for the type of TOE being
evaluated, as may be supplied by the evaluation authority;
b)
bypassing;
c)
tampering;
d)
direct attacks;
e)
monitoring;
f)
misuse.
1450
Items b) - f) are explained in greater detail in Annex B.
1451
The security architecture description should be considered in light of each of
the above generic potential vulnerabilities. Each potential vulnerability
should be considered to search for possible ways in which to defeat the TSF
protection and undermine the TSF.
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AVA_VAN.2-5
The evaluator shall record in the ETR the identified potential vulnerabilities
that are candidates for testing and applicable to the TOE in its operational
environment.
1452
It may be identified that no further consideration of the potential
vulnerability is required if for example the evaluator identifies that measures
in the operational environment, either IT or non-IT, prevent exploitation of
the potential vulnerability in that operational environment. For instance,
restricting physical access to the TOE to authorised users only may
effectively render a potential vulnerability to tampering unexploitable.
1453
The evaluator records any reasons for exclusion of potential vulnerabilities
from further consideration if the evaluator determines that the potential
vulnerability is not applicable in the operational environment. Otherwise the
evaluator records the potential vulnerability for further consideration.
1454
A list of potential vulnerabilities applicable to the TOE in its operational
environment, which can be used as an input into penetration testing
activities, shall be reported in the ETR by the evaluators.
15.2.2.7
Action AVA_VAN.2.4E
AVA_VAN.2-6
The evaluator shall devise penetration tests, based on the independent search
for potential vulnerabilities.
1455
The evaluator prepares for penetration testing as necessary to determine the
susceptibility of the TOE, in its operational environment, to the potential
vulnerabilities identified during the search of the sources of publicly
available information and the analysis of the TOE guidance and design
evidence. The evaluator should have access to current information (e.g. from
the evaluation authority) regarding known potential vulnerabilities that may
not have been considered by the evaluator.
1456
The evaluator is reminded that, as for considering the security architecture
description in the search for vulnerabilities (as detailed in AVA_VAN.2-3),
testing should be performed to confirm the architectural properties. This is
likely to require negative tests attempting to disprove the properties of the
security architecture. In developing the strategy for penetration testing, the
evaluator will ensure that each of the major characteristics of the security
architecture description are tested, either in functional testing (as considered
in 14) or evaluator penetration testing.
1457
The evaluator will probably find it practical to carry out penetration test
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1458
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required a Basic attack
potential. In some cases, however, it will be necessary to carry out a test
before the exploitability can be determined. Where, as a result of evaluation
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expertise, the evaluator discovers an exploitable vulnerability that is beyond
Basic attack potential, this is reported in the ETR as a residual vulnerability.
1459
Guidance on determining the necessary attack potential to exploit a potential
vulnerability can be found in Annex B.4.
1460
Potential vulnerabilities hypothesised as exploitable only by attackers
possessing Enhanced-Basic, Moderate or High attack potential do not result
in a failure of this evaluator action. Where analysis supports the hypothesis,
these need not be considered further as an input to penetration testing.
However, such vulnerabilities are reported in the ETR as residual
vulnerabilities.
1461
Potential vulnerabilities hypothesised as exploitable by an attacker
possessing a Basic attack potential and resulting in a violation of the security
objectives should be the highest priority potential vulnerabilities comprising
the list used to direct penetration testing against the TOE.
AVA_VAN.2-7
The evaluator shall produce penetration test documentation for the tests
based on the list of potential vulnerabilities in sufficient detail to enable the
tests to be repeatable. The test documentation shall include:
a)
identification of the potential vulnerability the TOE is being tested
for;
b)
instructions to connect and setup all required test equipment as
required to conduct the penetration test;
c)
instructions to establish all penetration test prerequisite initial
conditions;
d)
instructions to stimulate the TSF;
e)
instructions for observing the behaviour of the TSF;
f)
descriptions of all expected results and the necessary analysis to be
performed on the observed behaviour for comparison against
expected results;
g)
instructions to conclude the test and establish the necessary post-test
state for the TOE.
1462
The evaluator prepares for penetration testing based on the list of potential
vulnerabilities identified during the search of the public domain and the
analysis of the evaluation evidence.
1463
The evaluator is not expected to determine the exploitability for potential
vulnerabilities beyond those for which a Basic attack potential is required to
effect an attack. However, as a result of evaluation expertise, the evaluator
may discover a potential vulnerability that is exploitable only by an attacker
with greater than Basic attack potential. Such vulnerabilities are to be
reported in the ETR as residual vulnerabilities.
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1464
With an understanding of the potential vulnerability, the evaluator
determines the most feasible way to test for the TOE's susceptibility.
Specifically the evaluator considers:
a)
the TSFI or other TOE interface that will be used to stimulate the
TSF and observe responses (It is possible that the evaluator will need
to use an interface to the TOE other than the TSFI to demonstrate
properties of the TSF such as those described in the security
architecture description (as required by ADV_ARC). It should the
noted, that although these TOE interfaces provide a means of testing
the TSF properties, they are not the subject of the test.);
b)
initial conditions that will need to exist for the test (i.e. any particular
objects or subjects that will need to exist and security attributes they
will need to have);
c)
special test equipment that will be required to either stimulate a TSFI
or make observations of a TSFI (although it is unlikely that specialist
equipment would be required to exploit a potential vulnerability
assuming a Basic attack potential);
d)
whether theoretical analysis should replace physical testing,
particularly relevant where the results of an initial test can be
extrapolated to demonstrate that repeated attempts of an attack are
likely to succeed after a given number of attempts.
1465
The evaluator will probably find it practical to carry out penetration testing
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1466
The intent of specifying this level of detail in the test documentation is to
allow another evaluator to repeat the tests and obtain an equivalent result.
AVA_VAN.2-8
The evaluator shall conduct penetration testing.
1467
The evaluator uses the penetration test documentation resulting from work
unit AVA_VAN.2-6 as a basis for executing penetration tests on the TOE,
but this does not preclude the evaluator from performing additional ad hoc
penetration tests. If required, the evaluator may devise ad hoc tests as a result
of information learnt during penetration testing that, if performed by the
evaluator, are to be recorded in the penetration test documentation. Such tests
may be required to follow up unexpected results or observations, or to
investigate potential vulnerabilities suggested to the evaluator during the preplanned testing.
1468
Should penetration testing show that a hypothesised potential vulnerability
does not exist, then the evaluator should determine whether or not the
evaluator's own analysis was incorrect, or if evaluation deliverables are
incorrect or incomplete.
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1469
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required a Basic attack
potential. In some cases, however, it will be necessary to carry out a test
before the exploitability can be determined. Where, as a result of evaluation
expertise, the evaluator discovers an exploitable vulnerability that is beyond
basic attack potential, this is reported in the ETR as a residual vulnerability.
AVA_VAN.2-9
The evaluator shall record the actual results of the penetration tests.
1470
While some specific details of the actual test results may be different from
those expected (e.g. time and date fields in an audit record) the overall result
should be identical. Any unexpected test results should be investigated. The
impact on the evaluation should be stated and justified.
AVA_VAN.2-10
The evaluator shall report in the ETR the evaluator penetration testing effort,
outlining the testing approach, configuration, depth and results.
1471
The penetration testing information reported in the ETR allows the evaluator
to convey the overall penetration testing approach and effort expended on
this sub-activity. The intent of providing this information is to give a
meaningful overview of the evaluator's penetration testing effort. It is not
intended that the information regarding penetration testing in the ETR be an
exact reproduction of specific test steps or results of individual penetration
tests. The intention is to provide enough detail to allow other evaluators and
evaluation authorities to gain some insight about the penetration testing
approach chosen, amount of penetration testing performed, TOE test
configurations, and the overall results of the penetration testing activity.
1472
Information that would typically be found in the ETR section regarding
evaluator penetration testing efforts is:
a)
TOE test configurations. The particular configurations of the TOE
that were penetration tested;
b)
TSFI penetration tested. A brief listing of the TSFI and other TOE
interfaces that were the focus of the penetration testing;
c)
Verdict for the sub-activity. The overall judgement on the results of
penetration testing.
1473
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the penetration testing the evaluator performed during the
evaluation.
AVA_VAN.2-11
The evaluator shall examine the results of all penetration testing to
determine that the TOE, in its operational environment, is resistant to an
attacker possessing a Basic attack potential.
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1474
If the results reveal that the TOE, in its operational environment, has
vulnerabilities exploitable by an attacker possessing less than an EnhancedBasic attack potential, then this evaluator action fails.
1475
The guidance in B.4 should be used to determine the attack potential required
to exploit a particular vulnerability and whether it can therefore be exploited
in the intended environment. It may not be necessary for the attack potential
to be calculated in every instance, only if there is some doubt as to whether
or not the vulnerability can be exploited by an attacker possessing an attack
potential less than Enhanced-Basic.
AVA_VAN.2-12
The evaluator shall report in the ETR all exploitable vulnerabilities and
residual vulnerabilities, detailing for each:
a)
its source (e.g. CEM activity being undertaken when it was
conceived, known to the evaluator, read in a publication);
b)
the SFR(s) not met;
c)
a description;
d)
whether it is exploitable in its operational environment or not (i.e.
exploitable or residual).
e)
the amount of time, level of expertise, level of knowledge of the
TOE, level of opportunity and the equipment required to perform the
identified vulnerabilities, and the corresponding values using the
tables 3 and 4 of Annex B.4.
15.2.3
Evaluation of sub-activity (AVA_VAN.3)
15.2.3.1
Objectives
1476
The objective of this sub-activity is to determine whether the TOE, in its
operational environment, has vulnerabilities exploitable by attackers
possessing Enhanced-Basic attack potential.
15.2.3.2
Input
1477
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the implementation subset selected;
f)
the guidance documentation;
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g)
the TOE suitable for testing;
h)
information publicly available to support the identification of
possible potential vulnerabilities.
1478
The remaining implicit evaluation evidence for this sub-activity depends on
the components that have been included in the assurance package. The
evidence provided for each component is to be used as input in this subactivity.
1479
Other input for this sub-activity is:
a)
current information regarding public domain potential vulnerabilities
and attacks (e.g. from an evaluation authority).
15.2.3.3
Application notes
1480
During the conduct of evaluation activities the evaluator may also identify
areas of concern. These are specific portions of the TOE evidence that the
evaluator has some reservation about, although the evidence meets the
requirements for the activity with which the evidence is associated. For
example, a particular interface specification looks particularly complex, and
therefore may be prone to error either in the development of the TOE or in
the operation of the TOE. There is no potential vulnerability apparent at this
stage, further investigation is required. This is beyond the bounds of
encountered, as further investigation is required.
1481
The focused approach to the identification of potential vulnerabilities is an
analysis of the evidence with the aim of identifying any potential
vulnerabilities evident through the contained information. It is an
unstructured analysis, as the approach is not predetermined. Further guidance
on focused vulnerability analysis can be found in Annex B.2.2.2.2.
15.2.3.4
Action AVA_VAN.3.1E
AVA_VAN.3.1C
The TOE shall be suitable for testing.
AVA_VAN.3-1
The evaluator shall examine the TOE to determine that the test configuration
is consistent with the configuration under evaluation as specified in the ST.
1482
The TOE provided by the developer and identified in the test plan should
have the same unique reference as established by the CM capabilities
(ALC_CMC) sub-activities and identified in the ST introduction.
1483
It is possible for the ST to specify more than one configuration for
evaluation. The TOE may comprise a number of distinct hardware and
software entities that need to be tested in accordance with the ST. The
evaluator verifies that all test configurations are consistent with the ST.
1484
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment and
ensure they are met in the testing environment. There may be some
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objectives for the operational environment that do not apply to the test
environment. For example, an objective about user clearances may not apply;
however, an objective about a single point of connection to a network would
apply.
1485
If any test resources are used (e.g. meters, analysers) it will be the evaluator's
responsibility to ensure that these resources are calibrated correctly.
AVA_VAN.3-2
The evaluator shall examine the TOE to determine that it has been installed
properly and is in a known state
1486
It is possible for the evaluator to determine the state of the TOE in a number
of ways. For example, previous successful completion of the Evaluation of
sub-activity (AGD_PRE.1) sub-activity will satisfy this work unit if the
evaluator still has confidence that the TOE being used for testing was
installed properly and is in a known state. If this is not the case, then the
evaluator should follow the developer's procedures to install and start up the
TOE, using the supplied guidance only.
1487
If the evaluator has to perform the installation procedures because the TOE is
in an unknown state, this work unit when successfully completed could
satisfy work unit AGD_PRE.1-5.
15.2.3.5
Action AVA_VAN.3.2E
AVA_VAN.3-3
The evaluator shall examine sources of information publicly available to
identify potential vulnerabilities in the TOE.
1488
The evaluator examines the sources of information publicly available to
support the identification of possible potential vulnerabilities in the TOE.
There are many sources of publicly available information which the
evaluator should consider using items such as those available on the world
wide web, including:
a)
specialist publications (magazines, books);
b)
research papers;
c)
conference proceedings.
1489
The evaluator should not constrain their consideration of publicly available
information to the above, but should consider any other relevant information
available.
1490
While examining the evidence provided the evaluator will use the
information in the public domain to further search for potential
vulnerabilities. Where the evaluators have identified areas of concern, the
evaluator should consider information publicly available that relate to those
areas of concern.
1491
The availability of information that may be readily available to an attacker
that helps to identify and facilitate attacks may substantially enhance the
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attack potential of a given attacker. The accessibility of vulnerability
information and sophisticated attack tools on the Internet makes it more
likely that this information will be used in attempts to identify potential
vulnerabilities in the TOE and exploit them. Modern search tools make such
information easily available to the evaluator, and the determination of
resistance to published potential vulnerabilities and well known generic
attacks can be achieved in a cost-effective manner.
1492
The search of the information publicly available should be focused on those
sources that refer to the technologies used in the development of the product
from which the TOE is derived. The extensiveness of this search should
consider the following factors: TOE type, evaluator experience in this TOE
type, expected attack potential and the level of ADV evidence available.
1493
The identification process is iterative, where the identification of one
potential vulnerability may lead to identifying another area of concern that
requires further investigation.
1494
The evaluator will report what actions were taken to identify potential
vulnerabilities in the evidence. However, in this type of search, the evaluator
may not be able to describe the steps in identifying potential vulnerabilities
before the outset of the examination, as the approach may evolve as a result
of findings during the search.
1495
The evaluator will report the evidence examined in completing the search for
potential vulnerabilities. This selection of evidence may be derived from
those areas of concern identified by the evaluator, linked to the evidence the
attacker is assumed to be able to obtain, or according to another rationale
provided by the evaluator.
15.2.3.6
Action AVA_VAN.3.3E
AVA_VAN.3-4
The evaluator shall conduct a focused search of ST, guidance
documentation, functional specification, TOE design, security architecture
description and implementation representation to identify possible potential
vulnerabilities in the TOE.
1496
A flaw hypothesis methodology should be used whereby specifications and
development and guidance evidence are analysed and then potential
vulnerabilities in the TOE are hypothesised, or speculated.
1497
The evaluator should use the knowledge of the TOE design and operation
gained from the TOE deliverables to conduct a flaw hypothesis to identify
potential flaws in the development of the TOE and potential errors in the
specified method of operation of the TOE.
1498
The security architecture description provides the developer vulnerability
analysis, as it documents how the TSF protects itself from interference from
untrusted subjects and prevents the bypass of security enforcement
functionality. Therefore, the evaluator should build upon the understanding
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of the TSF protection gained from the analysis of this evidence and then
develop this in the knowledge gained from other development (11 evidence.
1499
The following provide some examples of hypotheses that may be created
when examining the evidence:
a)
consideration of malformed input for interfaces available to an
attacker at the external interfaces;
b)
examination of a key security mechanism cited in the security
architecture description, such as process separation, hypothesising
internal buffer overflows that may lead to degradation of separation;
c)
search to identify any objects created in the TOE implementation
representation that are then not fully controlled by the TSF, and could
be used by an attacker to undermine SFRs.
1500
The approach taken is directed by areas of concern identified during
examination of the evidence during the conduct of evaluation activities and
ensuring a representative sample of the development and guidance evidence
provided for the evaluation is searched.
1501
For guidance on sampling see Annex A.2. This guidance should be
considered when selecting the subset, giving reasons for:
a)
the approach used in selection;
b)
qualification that the evidence to be examined supports that approach.
1502
The areas of concern may relate to the sufficiency of specific protection
features detailed in the security architecture description.
1503
The evidence to be considered during the vulnerability analysis may be
linked to the evidence the attacker is assumed to be able to obtain. For
example, the developer may protect the TOE design and implementation
representations, so the only information assumed to be available to an
attacker is the functional specification and guidance (available publicly
available). So, although the objectives for assurance in the TOE ensure the
TOE design and implementation representation requirements are met, these
design representations may only be searched to further investigate areas of
concerns.
1504
On the other hand, if the source is available publicly available it would be
reasonable to assume that the attacker has access to the source and can use
this in attempts to attack the TOE. Therefore, the source should be
considered in the focused examination approach.
1505
The following indicates examples for the selection of the subset of evidence
to be considered:
a)
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provided, examination of information in the functional specification
and the implementation representation may be selected, as the
functional specification provides detail of interfaces available to an
attacker, and the implementation representation incorporates the
design decisions made at all other design abstractions. Therefore, the
TOE design information will be considered as part of the
implementation representation.
b)
Examination of a particular subset of information in each of the
design representations provided for the evaluation.
c)
Coverage of particular SFRs through each of the design
representations provided for the evaluation.
d)
Examination of each of the design representations provided for the
evaluation, considering different SFRs within each design
representations.
e)
Examination of aspects of the evidence provided for the evaluation
relating to current potential vulnerability information the evaluator
has received (e.g. from a scheme).
1506
This approach to identification of potential vulnerabilities is to take an
ordered and planned approach; applying a system to the examination. The
evaluator is to describe the method to be used in terms of what evidence will
be considered, the information within the evidence that is to be examined,
the manner in which this information is to be considered and the hypothesis
that is to be created.
1507
The following provide some examples that a hypothesis may take:
a)
consideration of malformed input for interfaces available to an
attacker at the external interfaces;
b)
examination of a key security mechanism cited in the security
architecture description, such as process separation, hypothesising
internal buffer overflows that may lead to degradation of separation;
c)
search to identify any objects created in the TOE implementation
representation that are then not fully controlled by the TSF, and could
be used by an attacker to undermine SFRs.
1508
For example, the evaluator may identify that interfaces are a potential area of
weakness in the TOE and specify an approach to the search that “all interface
specifications provided in the functional specification and TOE design will
be searched to hypothesise potential vulnerabilities” and go on to explain the
methods used in the hypothesis.
1509
The identification process is iterative, where the identification of one
potential vulnerability may lead to identifying another area of concern that
requires further investigation.
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1510
The evaluator will report what actions were taken to identify potential
vulnerabilities in the evidence. However, in this type of search, the evaluator
may not be able to describe the steps in identifying potential vulnerabilities
before the outset of the examination, as the approach may evolve as a result
of findings during the search.
1511
The evaluator will report the evidence examine in completing the search for
potential vulnerabilities. This selection of evidence may be derived from
those areas of concern identified by the evaluator, linked to the evidence the
attacker is assumed to be able to obtain, or according to another rationale
provided by the evaluator.
1512
Subject to the SFRs the TOE is to meet in the operational environment, the
evaluator's independent vulnerability analysis should consider generic
potential vulnerabilities under each of the following headings:
a)
generic potential vulnerabilities relevant for the type of TOE being
evaluated, as may be supplied by the evaluation authority;
b)
bypassing;
c)
tampering;
d)
direct attacks;
e)
monitoring;
f)
misuse.
1513
Items b) - f) are explained in greater detail in Annex B.
1514
The security architecture description should be considered in light of each of
the above generic potential vulnerabilities. Each potential vulnerability
should be considered to search for possible ways in which to defeat the TSF
protection and undermine the TSF.
AVA_VAN.3-5
The evaluator shall record in the ETR the identified potential vulnerabilities
that are candidates for testing and applicable to the TOE in its operational
environment.
1515
It may be identified that no further consideration of the potential
vulnerability is required if for example the evaluator identifies that measures
in the operational environment, either IT or non-IT, prevent exploitation of
the potential vulnerability in that operational environment. For instance,
restricting physical access to the TOE to authorised users only may
effectively render a potential vulnerability to tampering unexploitable.
1516
The evaluator records any reasons for exclusion of potential vulnerabilities
from further consideration if the evaluator determines that the potential
vulnerability is not applicable in the operational environment. Otherwise the
evaluator records the potential vulnerability for further consideration.
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1517
A list of potential vulnerabilities applicable to the TOE in its operational
environment, which can be used as an input into penetration testing
activities, shall be reported in the ETR by the evaluators.
15.2.3.7
Action AVA_VAN.3.4E
AVA_VAN.3-6
The evaluator shall devise penetration tests, based on the independent search
for potential vulnerabilities.
1518
The evaluator prepares for penetration testing as necessary to determine the
susceptibility of the TOE, in its operational environment, to the potential
vulnerabilities identified during the search of the sources of publicly
available information and the analysis of the TOE guidance and design
evidence. The evaluator should have access to current information (e.g. from
the evaluation authority) regarding known potential vulnerabilities that may
not have been considered by the evaluator.
1519
The evaluator is reminded that, as for considering the security architecture
description in the search for vulnerabilities (as detailed in AVA_VAN.3-3),
testing should be performed to confirm the architectural properties. If
requirements from ATE_DPT are included in the SARs, the developer
testing evidence will include testing performed to confirm the correct
implementation of any specific mechanisms detailed in the security
architecture description. However, the developer testing will not necessarily
include testing of all aspects of the architectural properties that protect the
TSF, as much of this testing will be negative testing in nature, attempting to
disprove the properties. In developing the strategy for penetration testing, the
evaluator will ensure that all aspects of the security architecture description
are tested, either in functional testing (as considered in 14) or evaluator
penetration testing.
1520
It will probably be practical to carry out penetration test using a series of test
cases, where each test case will test for a specific potential vulnerability.
1521
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required an Enhanced-Basic
attack potential. In some cases, however, it will be necessary to carry out a
test before the exploitability can be determined. Where, as a result of
evaluation expertise, the evaluator discovers an exploitable vulnerability that
is beyond Enhanced-Basic attack potential, this is reported in the ETR as a
residual vulnerability.
1522
Guidance on determining the necessary attack potential to exploit a potential
vulnerability can be found in Annex B.4.
1523
Potential vulnerabilities hypothesised as exploitable only by attackers
possessing Moderate or High attack potential do not result in a failure of this
evaluator action. Where analysis supports the hypothesis, these need not be
considered further as an input to penetration testing. However, such
vulnerabilities are reported in the ETR as residual vulnerabilities.
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1524
Potential vulnerabilities hypothesised as exploitable by an attacker
possessing a Basic or Enhanced-Basic attack potential and resulting in a
violation of the security objectives should be the highest priority potential
vulnerabilities comprising the list used to direct penetration testing against
the TOE.
AVA_VAN.3-7
The evaluator shall produce penetration test documentation for the tests
based on the list of potential vulnerabilities in sufficient detail to enable the
tests to be repeatable. The test documentation shall include:
a)
identification of the potential vulnerability the TOE is being tested
for;
b)
instructions to connect and setup all required test equipment as
required to conduct the penetration test;
c)
instructions to establish all penetration test prerequisite initial
conditions;
d)
instructions to stimulate the TSF;
e)
instructions for observing the behaviour of the TSF;
f)
descriptions of all expected results and the necessary analysis to be
performed on the observed behaviour for comparison against
expected results;
g)
instructions to conclude the test and establish the necessary post-test
state for the TOE.
1525
The evaluator prepares for penetration testing based on the list of potential
vulnerabilities identified during the search of the public domain and the
analysis of the evaluation evidence.
1526
The evaluator is not expected to determine the exploitability for potential
vulnerabilities beyond those for which an Enhanced-Basic attack potential is
required to effect an attack. However, as a result of evaluation expertise, the
evaluator may discover a potential vulnerability that is exploitable only by an
attacker with greater than Enhanced-Basic attack potential. Such
vulnerabilities are to be reported in the ETR as residual vulnerabilities.
1527
With an understanding of the potential vulnerability, the evaluator
determines the most feasible way to test for the TOE's susceptibility.
Specifically the evaluator considers:
a)
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the TSFI or other TOE interface that will be used to stimulate the
TSF and observe responses (It is possible that the evaluator will need
to use an interface to the TOE other than the TSFI to demonstrate
properties of the TSF such as those described in the security
architecture description (as required by ADV_ARC). It should the
noted, that although these TOE interfaces provide a means of testing
the TSF properties, they are not the subject of the test.);
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b)
initial conditions that will need to exist for the test (i.e. any particular
objects or subjects that will need to exist and security attributes they
will need to have);
c)
special test equipment that will be required to either stimulate a TSFI
or make observations of a TSFI (although it is unlikely that specialist
equipment would be required to exploit a potential vulnerability
assuming an Enhanced-Basic attack potential);
d)
whether theoretical analysis should replace physical testing,
particularly relevant where the results of an initial test can be
extrapolated to demonstrate that repeated attempts of an attack are
likely to succeed after a given number of attempts.
1528
The evaluator will probably find it practical to carry out penetration testing
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1529
The intent of specifying this level of detail in the test documentation is to
allow another evaluator to repeat the tests and obtain an equivalent result.
AVA_VAN.3-8
The evaluator shall conduct penetration testing.
1530
The evaluator uses the penetration test documentation resulting from work
unit AVA_VAN.3-6 as a basis for executing penetration tests on the TOE,
but this does not preclude the evaluator from performing additional ad hoc
penetration tests. If required, the evaluator may devise ad hoc tests as a result
of information learnt during penetration testing that, if performed by the
evaluator, are to be recorded in the penetration test documentation. Such tests
may be required to follow up unexpected results or observations, or to
investigate potential vulnerabilities suggested to the evaluator during the preplanned testing.
1531
Should penetration testing show that a hypothesised potential vulnerability
does not exist, then the evaluator should determine whether or not the
evaluator's own analysis was incorrect, or if evaluation deliverables are
incorrect or incomplete.
1532
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required an Enhanced-Basic
attack potential. In some cases, however, it will be necessary to carry out a
test before the exploitability can be determined. Where, as a result of
evaluation expertise, the evaluator discovers an exploitable vulnerability that
is beyond Enhanced-Basic attack potential, this is reported in the ETR as a
residual vulnerability.
AVA_VAN.3-9
The evaluator shall record the actual results of the penetration tests.
1533
While some specific details of the actual test results may be different from
those expected (e.g. time and date fields in an audit record) the overall result
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should be identical. Any unexpected test results should be investigated. The
impact on the evaluation should be stated and justified.
AVA_VAN.3-10
The evaluator shall report in the ETR the evaluator penetration testing effort,
outlining the testing approach, configuration, depth and results.
1534
The penetration testing information reported in the ETR allows the evaluator
to convey the overall penetration testing approach and effort expended on
this sub-activity. The intent of providing this information is to give a
meaningful overview of the evaluator's penetration testing effort. It is not
intended that the information regarding penetration testing in the ETR be an
exact reproduction of specific test steps or results of individual penetration
tests. The intention is to provide enough detail to allow other evaluators and
evaluation authorities to gain some insight about the penetration testing
approach chosen, amount of penetration testing performed, TOE test
configurations, and the overall results of the penetration testing activity.
1535
Information that would typically be found in the ETR section regarding
evaluator penetration testing efforts is:
a)
TOE test configurations. The particular configurations of the TOE
that were penetration tested;
b)
TSFI penetration tested. A brief listing of the TSFI and other TOE
interfaces that were the focus of the penetration testing;
c)
Verdict for the sub-activity. The overall judgement on the results of
penetration testing.
1536
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the penetration testing the evaluator performed during the
evaluation.
AVA_VAN.3-11
The evaluator shall examine the results of all penetration testing to
determine that the TOE, in its operational environment, is resistant to an
attacker possessing an Enhanced-Basic attack potential.
1537
If the results reveal that the TOE, in its operational environment, has
vulnerabilities exploitable by an attacker possessing less than Moderate
attack potential, then this evaluator action fails.
1538
The guidance in B.4 should be used to determine the attack potential required
to exploit a particular vulnerability and whether it can therefore be exploited
in the intended environment. It may not be necessary for the attack potential
to be calculated in every instance, only if there is some doubt as to whether
or not the vulnerability can be exploited by an attacker possessing an attack
potential less than Moderate.
AVA_VAN.3-12
The evaluator shall report in the ETR all exploitable vulnerabilities and
residual vulnerabilities, detailing for each:
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a)
its source (e.g. CEM activity being undertaken when it was
conceived, known to the evaluator, read in a publication);
b)
the SFR(s) not met;
c)
a description;
d)
whether it is exploitable in its operational environment or not (i.e.
exploitable or residual).
e)
the amount of time, level of expertise, level of knowledge of the
TOE, level of opportunity and the equipment required to perform the
identified vulnerabilities, and the corresponding values using the
tables 3 and 4 of Annex B.4.
15.2.4
Evaluation of sub-activity (AVA_VAN.4)
15.2.4.1
Objectives
1539
The objective of this sub-activity is to determine whether the TOE, in its
operational environment, has vulnerabilities exploitable by attackers
possessing Moderate attack potential.
15.2.4.2
Input
1540
The evaluation evidence for this sub-activity is:
a)
the ST;
b)
the functional specification;
c)
the TOE design;
d)
the security architecture description;
e)
the implementation representation;
f)
the guidance documentation;
g)
the TOE suitable for testing;
h)
information publicly available to support the identification of
possible potential vulnerabilities.
1541
The remaining implicit evaluation evidence for this sub-activity depends on
the components that have been included in the assurance package. The
evidence provided for each component is to be used as input in this subactivity.
1542
Other input for this sub-activity is:
a)
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current information regarding public domain potential vulnerabilities
and attacks (e.g. from an evaluation authority).
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15.2.4.3
Application notes
1543
The methodical analysis approach takes the form of a structured examination
of the evidence. This method requires the evaluator to specify the structure
and form the analysis will take (i.e. the manner in which the analysis is
performed is predetermined, unlike the focused analysis). The method is
specified in terms of the information that will be considered and how/why it
will be considered. Further guidance on methodical vulnerability analysis
can be found in Annex B.2.2.2.3.
15.2.4.4
Action AVA_VAN.4.1E
AVA_VAN.4.1C
The TOE shall be suitable for testing.
AVA_VAN.4-1
The evaluator shall examine the TOE to determine that the test configuration
is consistent with the configuration under evaluation as specified in the ST.
1544
The TOE provided by the developer and identified in the test plan should
have the same unique reference as established by the CM capabilities
(ALC_CMC) sub-activities and identified in the ST introduction.
1545
It is possible for the ST to specify more than one configuration for
evaluation. The TOE may comprise a number of distinct hardware and
software entities that need to be tested in accordance with the ST. The
evaluator verifies that all test configurations are consistent with the ST.
1546
The evaluator should consider the security objectives for the operational
environment described in the ST that may apply to the test environment and
ensure they are met in the testing environment. There may be some
objectives for the operational environment that do not apply to the test
environment. For example, an objective about user clearances may not apply;
however, an objective about a single point of connection to a network would
apply.
1547
If any test resources are used (e.g. meters, analysers) it will be the evaluator's
responsibility to ensure that these resources are calibrated correctly.
AVA_VAN.4-2
The evaluator shall examine the TOE to determine that it has been installed
properly and is in a known state
1548
It is possible for the evaluator to determine the state of the TOE in a number
of ways. For example, previous successful completion of the Evaluation of
sub-activity (AGD_PRE.1) sub-activity will satisfy this work unit if the
evaluator still has confidence that the TOE being used for testing was
installed properly and is in a known state. If this is not the case, then the
evaluator should follow the developer's procedures to install and start up the
TOE, using the supplied guidance only.
1549
If the evaluator has to perform the installation procedures because the TOE is
in an unknown state, this work unit when successfully completed could
satisfy work unit AGD_PRE.1-5.
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15.2.4.5
Action AVA_VAN.4.2E
AVA_VAN.4-3
The evaluator shall examine sources of information publicly available to
identify potential vulnerabilities in the TOE.
1550
The evaluator examines the sources of information publicly available to
support the identification of possible potential vulnerabilities in the TOE.
There are many sources of publicly available information which the
evaluator should consider using items such as those available on the world
wide web, including:
a)
specialist publications (magazines, books);
b)
research papers;
c)
conference proceedings.
1551
The evaluator should not constrain their consideration of publicly available
information to the above, but should consider any other relevant information
available.
1552
While examining the evidence provided the evaluator will use the
information in the public domain to further search for potential
vulnerabilities. Where the evaluators have identified areas of concern, the
evaluator should consider information publicly available that relate to those
areas of concern.
1553
The availability of information that may be readily available to an attacker
that helps to identify and facilitate attacks may substantially enhance the
attack potential of a given attacker. The accessibility of vulnerability
information and sophisticated attack tools on the Internet makes it more
likely that this information will be used in attempts to identify potential
vulnerabilities in the TOE and exploit them. Modern search tools make such
information easily available to the evaluator, and the determination of
resistance to published potential vulnerabilities and well known generic
attacks can be achieved in a cost-effective manner.
1554
The search of the information publicly available should be focused on those
sources that refer to the technologies used in the development of the product
from which the TOE is derived. The extensiveness of this search should
consider the following factors: TOE type, evaluator experience in this TOE
type, expected attack potential and the level of ADV evidence available.
1555
The identification process is iterative, where the identification of one
potential vulnerability may lead to identifying another area of concern that
requires further investigation.
1556
The evaluator will describe the approach to be taken to identify potential
vulnerabilities in the publicly available material, detailing the search to be
performed. This may be driven by factors such as areas of concern identified
by the evaluator, linked to the evidence the attacker is assumed to be able to
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obtain. However, it is recognised that in this type of search the approach may
further evolve as a result of findings during the search. Therefore, the
evaluator will also report any actions taken in addition to those described in
the approach to further investigate issues thought to lead to potential
vulnerabilities, and will report the evidence examined in completing the
search for potential vulnerabilities.
15.2.4.6
Action AVA_VAN.4.3E
AVA_VAN.4-4
The evaluator shall conduct a methodical analysis of ST, guidance
documentation, functional specification, TOE design, security architecture
description and implementation representation to identify possible potential
vulnerabilities in the TOE.
1557
Guidance on methodical vulnerability analysis is provided in Annex
B.2.2.2.3.
1558
This approach to identification of potential vulnerabilities is to take an
ordered and planned approach. A system is to be applied in the examination.
The evaluator is to describe the method to be used in terms of the manner in
which this information is to be considered and the hypothesis that is to be
created.
1559
A flaw hypothesis methodology should be used whereby the ST,
development (functional specification, TOE design and implementation
representation) and guidance evidence are analysed and then vulnerabilities
in the TOE are hypothesised, or speculated.
1560
The evaluator should use the knowledge of the TOE design and operation
gained from the TOE deliverables to conduct a flaw hypothesis to identify
potential flaws in the development of the TOE and potential errors in the
specified method of operation of the TOE.
1561
The security architecture description provides the developer vulnerability
analysis, as it documents how the TSF protects itself from interference from
untrusted subjects and prevents the bypass of security enforcement
functionality. Therefore, the evaluator should build upon the understanding
of the TSF protection gained from the analysis of this evidence and then
develop this in the knowledge gained from other development (11 evidence.
1562
The approach taken to the methodical search for vulnerabilities is to consider
any areas of concern identified in the results of the evaluator's assessment of
the development and guidance evidence. However, the evaluator should also
consider each aspect of the security architecture analysis to search for any
ways in which the protection of the TSF can be undermined. It may be
helpful to structure the methodical analysis on the basis of the material
presented in the security architecture description, introducing concerns from
other 11 evidence as appropriate. The analysis can then be further developed
to ensure all other material from the 11 evidence is considered.
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1563
The following provide some examples of hypotheses that may be created
when examining the evidence:
a)
consideration of malformed input for interfaces available to an
attacker at the external interfaces;
b)
examination of a key security mechanism cited in the security
architecture description, such as process separation, hypothesising
internal buffer overflows that may lead to degradation of separation;
c)
search to identify any objects created in the TOE implementation
representation that are then not fully controlled by the TSF, and could
be used by an attacker to undermine SFRs.
1564
For example, the evaluator may identify that interfaces are a potential area of
weakness in the TOE and specify an approach to the search that 'all interface
specifications in the evidence provided will be searched to hypothesise
potential vulnerabilities' and go on to explain the methods used in the
hypothesis.
1565
In addition, areas of concern the evaluator has identified during examination
of the evidence during the conduct of evaluation activities. Areas of concern
may also be identified during the conduct of other work units associated with
this component, in particular AVA_VAN.4-7, AVA_VAN.4-5 and
AVA_VAN.4-6) where the development and conduct of penetration tests
may identify further areas of concerns for investigation, or potential
vulnerabilities.
1566
However, examination of only a subset of the development and guidance
evidence or their contents is not permitted in this level of rigour. The
approach description should provide a demonstration that the methodical
approach used is complete, providing confidence that the approach used to
search the deliverables has considered all of the information provided in
those deliverables.
1567
This approach to identification of potential vulnerabilities is to take an
ordered and planned approach; applying a system to the examination. The
evaluator is to describe the method to be used in terms of how the evidence
will be considered; the manner in which this information is to be considered
and the hypothesis that is to be created. This approach should be agreed with
the evaluation authority, and the evaluation authority should provide detail of
any additional approaches the evaluator should take to the vulnerability
analysis and identify any additional information that should be considered by
the evaluator.
1568
Although a system to identifying potential vulnerabilities is predefined, the
identification process may still be iterative, where the identification of one
potential vulnerability may lead to identifying another area of concern that
requires further investigation.
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1569
Subject to the SFRs the TOE is to meet in the operational environment, the
evaluator's independent vulnerability analysis should consider generic
potential vulnerabilities under each of the following headings:
a)
generic potential vulnerabilities relevant for the type of TOE being
evaluated, as may be supplied by the evaluation authority;
b)
bypassing;
c)
tampering;
d)
direct attacks;
e)
monitoring;
f)
misuse.
1570
Items b) - f) are explained in greater detail in Annex B.
1571
The security architecture description should be considered in light of each of
the above generic potential vulnerabilities. Each potential vulnerability
should be considered to search for possible ways in which to defeat the TSF
protection and undermine the TSF.
AVA_VAN.4-5
The evaluator shall record in the ETR the identified potential vulnerabilities
that are candidates for testing and applicable to the TOE in its operational
environment.
1572
It may be identified that no further consideration of the potential
vulnerability is required if for example the evaluator identifies that measures
in the operational environment, either IT or non-IT, prevent exploitation of
the potential vulnerability in that operational environment. For instance,
restricting physical access to the TOE to authorised users only may
effectively render a potential vulnerability to tampering unexploitable.
1573
The evaluator records any reasons for exclusion of potential vulnerabilities
from further consideration if the evaluator determines that the potential
vulnerability is not applicable in the operational environment. Otherwise the
evaluator records the potential vulnerability for further consideration.
1574
A list of potential vulnerabilities applicable to the TOE in its operational
environment, which can be used as an input into penetration testing
activities, shall be reported in the ETR by the evaluators.
15.2.4.7
Action AVA_VAN.4.4E
AVA_VAN.4-6
The evaluator shall devise penetration tests, based on the independent search
for potential vulnerabilities.
1575
The evaluator prepares for penetration testing as necessary to determine the
susceptibility of the TOE, in its operational environment, to the potential
vulnerabilities identified during the search of the sources of publicly
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available information and the analysis of the TOE guidance and design
evidence. The evaluator should have access to current information (e.g. from
the evaluation authority) regarding known potential vulnerabilities that may
not have been considered by the evaluator.
1576
The evaluator is reminded that, as for considering the security architecture
description in the search for vulnerabilities (as detailed in AVA_VAN.4-3),
testing should be performed to confirm the architectural properties. If
requirements from ATE_DPT are included in the SARs, the developer
testing evidence will include testing performed to confirm the correct
implementation of any specific mechanisms detailed in the security
architecture description. However, the developer testing will not necessarily
include testing of all aspects of the architectural properties that protect the
TSF, as much of this testing will be negative testing in nature, attempting to
disprove the properties. In developing the strategy for penetration testing, the
evaluator will ensure that all aspects of the security architecture description
are tested, either in functional testing (as considered in 14) or evaluator
penetration testing.
1577
The evaluator will probably find it practical to carry out penetration test
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1578
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required a Moderate attack
potential. In some cases, however, it will be necessary to carry out a test
before the exploitability can be determined. Where, as a result of evaluation
expertise, the evaluator discovers an exploitable vulnerability that is beyond
Moderate attack potential, this is reported in the ETR as a residual
vulnerability.
1579
Guidance on determining the necessary attack potential to exploit a potential
vulnerability can be found in Annex B.4.
1580
Potential vulnerabilities hypothesised as exploitable by an attacker
possessing a Moderate (or less) attack potential and resulting in a violation of
the security objectives should be the highest priority potential vulnerabilities
comprising the list used to direct penetration testing against the TOE.
AVA_VAN.4-7
The evaluator shall produce penetration test documentation for the tests
based on the list of potential vulnerabilities in sufficient detail to enable the
tests to be repeatable. The test documentation shall include:
a)
identification of the potential vulnerability the TOE is being tested
for;
b)
instructions to connect and setup all required test equipment as
required to conduct the penetration test;
c)
instructions to establish all penetration test prerequisite initial
conditions;
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d)
instructions to stimulate the TSF;
e)
instructions for observing the behaviour of the TSF;
f)
descriptions of all expected results and the necessary analysis to be
performed on the observed behaviour for comparison against
expected results;
g)
instructions to conclude the test and establish the necessary post-test
state for the TOE.
1581
The evaluator prepares for penetration testing based on the list of potential
vulnerabilities identified during the search of the public domain and the
analysis of the evaluation evidence.
1582
The evaluator is not expected to determine the exploitability for potential
vulnerabilities beyond those for which a Moderate attack potential is
required to effect an attack. However, as a result of evaluation expertise, the
evaluator may discover a potential vulnerability that is exploitable only by an
attacker with greater than Moderate attack potential. Such vulnerabilities are
to be reported in the ETR as residual vulnerabilities.
1583
With an understanding of the potential vulnerability, the evaluator
determines the most feasible way to test for the TOE's susceptibility.
Specifically the evaluator considers:
a)
the TSFI or other TOE interface that will be used to stimulate the
TSF and observe responses (It is possible that the evaluator will need
to use an interface to the TOE other than the TSFI to demonstrate
properties of the TSF such as those described in the security
architecture description (as required by ADV_ARC). It should the
noted, that although these TOE interfaces provide a means of testing
the TSF properties, they are not the subject of the test.);
b)
initial conditions that will need to exist for the test (i.e. any particular
objects or subjects that will need to exist and security attributes they
will need to have);
c)
special test equipment that will be required to either stimulate a TSFI
or make observations of a TSFI;
d)
whether theoretical analysis should replace physical testing,
particularly relevant where the results of an initial test can be
extrapolated to demonstrate that repeated attempts of an attack are
likely to succeed after a given number of attempts.
1584
The evaluator will probably find it practical to carry out penetration testing
using a series of test cases, where each test case will test for a specific
potential vulnerability.
1585
The intent of specifying this level of detail in the test documentation is to
allow another evaluator to repeat the tests and obtain an equivalent result.
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AVA_VAN.4-8
The evaluator shall conduct penetration testing.
1586
The evaluator uses the penetration test documentation resulting from work
unit AVA_VAN.4-6 as a basis for executing penetration tests on the TOE,
but this does not preclude the evaluator from performing additional ad hoc
penetration tests. If required, the evaluator may devise ad hoc tests as a result
of information learnt during penetration testing that, if performed by the
evaluator, are to be recorded in the penetration test documentation. Such tests
may be required to follow up unexpected results or observations, or to
investigate potential vulnerabilities suggested to the evaluator during the preplanned testing.
1587
Should penetration testing show that a hypothesised potential vulnerability
does not exist, then the evaluator should determine whether or not the
evaluator's own analysis was incorrect, or if evaluation deliverables are
incorrect or incomplete.
1588
The evaluator is not expected to test for potential vulnerabilities (including
those in the public domain) beyond those which required a Moderate attack
potential. In some cases, however, it will be necessary to carry out a test
before the exploitability can be determined. Where, as a result of evaluation
expertise, the evaluator discovers an exploitable vulnerability that is beyond
Moderate attack potential, this is reported in the ETR as a residual
vulnerability.
AVA_VAN.4-9
The evaluator shall record the actual results of the penetration tests.
1589
While some specific details of the actual test results may be different from
those expected (e.g. time and date fields in an audit record) the overall result
should be identical. Any unexpected test results should be investigated. The
impact on the evaluation should be stated and justified.
AVA_VAN.4-10
The evaluator shall report in the ETR the evaluator penetration testing effort,
outlining the testing approach, configuration, depth and results.
1590
The penetration testing information reported in the ETR allows the evaluator
to convey the overall penetration testing approach and effort expended on
this sub-activity. The intent of providing this information is to give a
meaningful overview of the evaluator's penetration testing effort. It is not
intended that the information regarding penetration testing in the ETR be an
exact reproduction of specific test steps or results of individual penetration
tests. The intention is to provide enough detail to allow other evaluators and
evaluation authorities to gain some insight about the penetration testing
approach chosen, amount of penetration testing performed, TOE test
configurations, and the overall results of the penetration testing activity.
1591
Information that would typically be found in the ETR section regarding
evaluator penetration testing efforts is:
a)
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TOE test configurations. The particular configurations of the TOE
that were penetration tested;
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b)
TSFI penetration tested. A brief listing of the TSFI and other TOE
interfaces that were the focus of the penetration testing;
c)
Verdict for the sub-activity. The overall judgement on the results of
penetration testing.
1592
This list is by no means exhaustive and is only intended to provide some
context as to the type of information that should be present in the ETR
concerning the penetration testing the evaluator performed during the
evaluation.
AVA_VAN.4-11
The evaluator shall examine the results of all penetration testing to
determine that the TOE, in its operational environment, is resistant to an
attacker possessing a Moderate attack potential.
1593
If the results reveal that the TOE, in its operational environment, has
vulnerabilities exploitable by an attacker possessing less than a High attack
potential, then this evaluator action fails.
1594
The guidance in B.4 should be used to determine the attack potential required
to exploit a particular vulnerability and whether it can therefore be exploited
in the intended environment. It may not be necessary for the attack potential
to be calculated in every instance, only if there is some doubt as to whether
or not the vulnerability can be exploited by an attacker possessing an attack
potential less than High.
AVA_VAN.4-12
The evaluator shall report in the ETR all exploitable vulnerabilities and
residual vulnerabilities, detailing for each:
a)
its source (e.g. CEM activity being undertaken when it was
conceived, known to the evaluator, read in a publication);
b)
the SFR(s) not met;
c)
a description;
d)
whether it is exploitable in its operational environment or not (i.e.
exploitable or residual).
e)
the amount of time, level of expertise, level of knowledge of the
TOE, level of opportunity and the equipment required to perform the
identified vulnerabilities, and the corresponding values using the
tables 3 and 4 of Annex B.4.
15.2.5
Evaluation of sub-activity (AVA_VAN.5)
1595
There is no general guidance; the scheme should be consulted for guidance
on this sub-activity.
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Class ACO: Composition
16
Class ACO: Composition
16.1
Introduction
1596
The goal of this activity is to determine whether the components can be
integrated in a secure manner, as defined in the ST for the composed TOE.
This is achieved through examination and testing of the interfaces between
the components, supported by examination of the design of the components
and the conduct of vulnerability analysis.
16.2
Application notes
1597
The Reliance of dependent component (ACO_REL) family identifies where
the dependent component is reliant upon IT in its operational environment
(satisfied by a base component in the composed TOE evaluation) in order to
provide its own security services. This reliance is identified in terms of the
interfaces expected by the dependent component to be provided by the base
component. Development evidence (ACO_DEV) then determines which
interfaces of the base component were considered (as TSFI) during the
component evaluation of the base component.
1598
It should be noted that Reliance of dependent component (ACO_REL) does
not cover other evidence that may be needed to address the technical
integration problem of composing components (e.g. descriptions of non-TSF
interfaces of the operating system, rules for integration, etc.). This is outside
the security assessment of the composition and is a functional composition
issue.
1599
As part of Composed TOE testing (ACO_CTT) the evaluator will perform
testing of the composed TOE SFRs at the composed TOE interfaces and of
the interfaces of the base component relied upon by the dependent
component to confirm they operate as specified. The subset selected will
consider the possible effects of changes to the configuration/use of the base
component as used in the composed TOE. These changes are identified from
the configuration of the base component determined during the base
component evaluation. The developer will provide test evidence for each of
the base component interfaces (the requirements for coverage are consistent
with those applied to the evaluation of the base component).
1600
Composition rationale (ACO_COR) requires the evaluator to determine
whether the appropriate assurance measures have been applied to the base
component, and whether the base component is being used in its evaluated
configuration. This includes determination of whether all security
functionality required by the dependent component was within the TSF of
the base component. The Composition rationale (ACO_COR) requirement
may be met through the production of evidence that each of these is
demonstrated to be upheld. This evidence may be in the form of the security
target and a public report of the component evaluation (e.g. certification
report).
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1601
If, on the other hand, one of the above have not been upheld, then it may be
possible that an argument can be made as to why the assurance gained during
an original evaluation is unaffected. If this is not possible then additional
evaluation evidence for those aspects of the base component not covered
may have to be provided. This material is then assessed in Development
evidence (ACO_DEV).
1602
For example, it may be the case as described in the Interactions between
entities (see Annex B.3, Interactions between composed IT entities in CC
Part 3) that the dependent component requires the base component to provide
more security functionality in the composed TOE than included in the base
component evaluation. This would be determined during the application of
the Reliance of dependent component (ACO_REL) and Development
evidence (ACO_DEV) families. In this case the composition rationale
evidence provided for Composition rationale (ACO_COR) would
demonstrate that the assurance gained from the base component evaluation is
unaffected. This may be achieved by means including:
a)
Performing a re-evaluation of the base component focusing on the
evidence relating to the extended part of the TSF;
b)
Demonstrating that the extended part of the TSF cannot affect other
portions of the TSF, and providing evidence that the extended part of
the TSF provides the necessary security functionality.
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16.3
Composition rationale (ACO_COR)
16.3.1
Evaluation of sub-activity (ACO_COR.1)
16.3.1.1
Input
1603
The evaluation evidence for this sub-activity is:
a)
the composed ST;
b)
the composition rationale;
c)
the reliance information;
d)
the development information;
e)
unique identifier.
16.3.1.2
Action ACO_COR.1.1E
ACO_COR.1.1C
The composition rationale shall demonstrate that a level of assurance at
least as high as that of the dependent component has been obtained for the
support functionality of the base component, when the base component is
configured as required to support the TSF of the dependent component.
ACO_COR.1-1
The evaluator shall examine the correspondence analysis with the
development information and the reliance information to identify the
interfaces that are relied upon by the dependent component which are not
detailed in the development information.
1604
The evaluator's goal in this work unit is two fold:
a)
to determine which interfaces relied upon by the dependent
component have had the appropriate assurance measures applied.
b)
to determine that the assurance package applied to the base
component during the base component evaluation contained either
the same assurance requirements as those in the package applied to
the dependent component during its' evaluation, or hierarchically
higher assurance requirements.
1605
The evaluator may use the correspondence tracing in the development
information developed during the Development evidence (ACO_DEV)
activities (e.g. ACO_DEV.1-2, ACO_DEV.2-4, ACO_DEV.3-6) to help
identify the interfaces identified in the reliance information that are not
considered in the development information.
1606
The evaluator will record the SFR-enforcing interfaces described in the
reliance information that are not included in the development information.
These will provide input to ACO_COR.1-3 work unit, helping to identify the
portions of the base component in which further assurance is required.
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1607
If the both the base and dependent components were evaluated against the
same assurance package, then the determination of whether the level of
assurance in the portions within the base component evaluation is at least as
high as that of the dependent component is trivial. If however, the assurance
packages applied to the components during the component evaluations differ,
the evaluator needs to determine that the assurance requirements applied to
the base component are all hierarchically higher to the assurance
requirements applied to the dependent component.
ACO_COR.1-2
The evaluator shall examine the composition rationale to determine, for
those included base component interfaces on which the dependent TSF
relies, whether the interface was considered during the evaluation of the base
component.
1608
The ST, component public evaluation report (e.g. certification report) and
guidance documents for the base component all provide information on the
scope and boundary of the base component. The ST provides details of the
logical scope and boundary of the composed TOE, allowing the evaluator to
determine whether an interface relates to a portion of the product that was
within the scope of the evaluation. The guidance documentation provides
details of use of all interfaces for the composed TOE. Although the guidance
documentation may include details of interfaces in the product that are not
within the scope of the evaluation, any such interfaces should be identifiable,
either from the scoping information in the ST or through a portion of the
guidance that deals with the evaluated configuration. The public evaluation
report should provide any additional constraints on the use of the composed
TOE that are necessary.
1609
Therefore, the combination of these inputs allows the evaluator to determine
whether an interface described in the composition rationale has the necessary
assurance associated with it, or whether further assurance is required. The
evaluator will record those interfaces of the base component for which
additional assurance is required, for consideration during ACO_COR.1-3.
ACO_COR.1-3
The evaluator shall examine the composition rationale to determine that the
necessary assurance measures have been applied to the base component.
1610
The evaluation verdicts, and resultant assurance, for the base component can
be reused provided the same portions of the base component are used in the
composed TOE and they are used in a consistent manner.
1611
In order to determine whether the necessary assurance measures have already
been applied to the component, and the portions of the component for which
assurance measures still need to be applied, the evaluator should use the
output of the ACO_DEV.*.2E action and the work units ACO_COR.1-1 and
ACO_COR.1-2:
a)
September 2006
For those interfaces identified in the reliance information (Reliance of
dependent component (ACO_REL)), but not discussed in
development information (Development evidence (ACO_DEV)),
additional information is required. (Identified in ACO_COR.1-1.)
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b)
For those interfaces used inconsistently in the composed TOE from
the base component (difference between the information provided in
Development evidence (ACO_DEV) and Reliance of dependent
component (ACO_REL) the impact of the differences in use need to
be considered. (Identified in ACO_DEV.*.2E.)
c)
For those interfaces identified in composition rationale for which no
assurance has previously been gained, additional information is
required. (Identified in ACO_COR.1-2.)
d)
For those interfaces consistently described in the reliance
information, composition rationale and the development information,
no further action is required as the results from the base component
evaluation can be re-used.
1612
The interfaces of the base component reported to be required by the reliance
information but not included in the development information indicate the
portions of the base component where further assurance is required. The
interfaces identify the entry points into the base component.
1613
For those interfaces included in both the development information and
reliance information, the evaluator is to determine whether the interfaces are
being used in the composed TOE in a manner that is consistent with the base
component evaluation. The method of use of the interface will be considered
during the Development evidence (ACO_DEV) activities to determine that
the use of the interface is consistent in both the base component and the
composed TOE. The remaining consideration is the determination of whether
the configurations of the base component and the composed TOE are
consistent. To determine this, the evaluator will consider the guidance
documentation of each to ensure they are consistent (see further guidance
below regarding consistent guidance documentation). Any deviation in the
documentation will be further analysed by the evaluation to determine the
possible effects.
1614
For those interfaces that are consistently described in the reliance
information and development information, and for which the guidance is
consistent for the base component and the composed TOE, the required level
of assurance has been provided.
1615
The following subsections provide guidance on how to determine
consistency between assurance gained in the base component, the evidence
provided for the composed TOE, and the analysis performed by the evaluator
in the instances where inconsistencies are identified.
16.3.1.2.1
Development
1616
The reliance information identifies the interfaces in the dependent
component that are to be matched by the base component. If an interface
identified in the reliance information is not identified in the development
information, then the composition rationale is to provide a justification of
how the base component provides the required interfaces.
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1617
If an interface identified in the reliance information is identified in the
development information, but there are inconsistencies between the
descriptions, further analysis is required. The evaluator identifies the
differences in use of the base component as considered in the base
component evaluation and the composed TOE evaluation. The evaluator will
devise testing to be performed (during the conduct of Composed TOE testing
(ACO_CTT)) to test the interface.
1618
The patch status of the base and dependent components as used in the
composed TOE should be compared to the patch status of the components
during the component evaluations. If any patches have been applied to the
components, the composition rationale is to include details of the patches,
including any potential impact to the SFRs of the evaluated component. The
evaluator should consider the details of the changes provided and verify the
accuracy of the potential impact of the change on the component SFRs. The
evaluator should then consider whether the changes made by the patch
should be verified through testing, and will identify the necessary testing
approach. The testing may take the form of repeating the applicable
evaluator/developer testing performed for the component evaluation of the
component or it may be necessary for the evaluator to devise new tests to
confirm the modified component.
1619
If any of the individual components have been the subject of assurance
continuity activities since the completion of the component evaluation, the
evaluator will consider the changes assessed in the assurance continuity
activities during the independent vulnerability analysis activity for the
composed TOE (in Composition vulnerability analysis (ACO_VUL)).
16.3.1.2.2
Guidance
1620
The guidance for the composed TOE is likely to make substantial reference
out to the guidance for the individual components. The minimal guidance
expected to be necessary is the identification of any ordering dependencies in
the application of guidance for the dependent and base components,
particularly during the preparation (installation) of the composed TOE.
1621
In addition to the application of the Preparative procedures (AGD_PRE) and
Operational user guidance (AGD_OPE) families to the guidance for the
composed TOE, it is necessary to analyse the consistency between the
guidance for the components and the composed TOE, to identify any
deviations.
1622
If the composed TOE guidance refers out to the base component and
dependent component guidance, then the consideration for consistency is
limited to consistency between the guidance documentation provided for
each of the components (i.e. consistency between the base component
guidance and the dependent component guidance). However, if additional
guidance is provided for the composed TOE, to that provided for the
components, greater analysis is required, as consistency is also required
between the guidance documentation for the components and guidance
documentation for the composed TOE.
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1623
Consistent in this instance is understood to mean that either the guidance is
the same or it places additional constraints on the operation of the individual
components when combined, in a similar manner to refinement of
functional/assurance components.
1624
With the information available (that used as input for Development evidence
(ACO_DEV) or the development aspects discussed above) the evaluator may
be able to determine all possible impacts of the deviation from the
configuration of the base component specified in the component evaluation.
However, for high EALs (where evaluation of the base component included
TOE design (ADV_TDS) requirements) it is possible that, unless detailed
design abstractions for the base component are delivered as part of the
development information for the composed TOE, the possible impacts of the
modification to the guidance cannot be fully determined as the internals are
unknown. In this case the evaluator will report the residual risk of the
analysis.
1625
These residual risks are to be included in any public evaluation report for the
composed TOE.
1626
The evaluator will note these variances in the guidance for input into
evaluator independent testing activities (Composed TOE testing
(ACO_CTT)).
1627
The guidance for the composed TOE may add to the guidance for the
components, particularly in terms of installation and the ordering of
installation steps for the base component in relation to the installation steps
for the dependent component. The ordering of the steps for the installation of
the individual components should not change, however they may need to be
interleaved. The evaluator will examine this guidance to ensure that it still
meets the requirement of the AGD_PRE activity performed during the
evaluations of the components.
1628
It may be the case that the reliance information identifies that interfaces of
the base component, in addition to those identified as TSFIs of the base
component, are relied upon by the dependent component are identified in the
reliance information. It may be necessary for guidance to be provided for the
use of any such additional interfaces in the base component. Provided the
consumer of the composed TOE is to receive the guidance documentation for
the base component, then the results of the AGD_PRE and AGD_OPE
verdicts for the base component can be reused for those interfaces considered
in the evaluation of the base component. However, for the additional
interfaces relied upon by the dependent component, the evaluator will need
to determine that the guidance documentation for the base component meets
the requirements of AGD_PRE and AGD_OPE, as applied in the base
component evaluations.
1629
For those interfaces considered during the base component evaluation, and
therefore, for which assurance has already been gained, the evaluator will
ensure that the guidance for the use of each interface for the composed TOE
is consistent with that provided for the base component. To determine the
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guidance for the composed TOE is consistent with that for the base
component, the evaluator should perform a mapping for each interface to the
guidance provided for both the composed TOE and the base component. The
evaluator then compares the guidance to determine consistency.
1630
Examples of additional constraints provided in composed TOE guidance that
would be considered to be consistent with component guidance are (guidance
for a component is given followed by an example of guidance for a
composed TOE that would be considered to provide additional constraints):
−
Component: The password length must be set to a minimum of 8
characters length, including alphabetic and numeric characters.
−
Composed TOE: The password length must be set to a minimum of
10 characters in length, including alphabetic and numeric characters
and at least one of the following special characters: ( ) { } ^ < > - _
−
NOTE: It would only be acceptable to increase the password length
to [integer > 8] characters while removing the mandate for the
inclusion of both alphabetic and numeric characters for the composed
TOE, if the same or a higher metric was achieved for the strength
rating (taking into account the likelihood of the password being
guessed).
−
Component: The following services are to be disabled in the registry
settings: WWW Publishing Service and ICDBReporter service.
−
Composed TOE: The following services are to be disabled in the
registry settings: Publishing Service, ICDBReporter service, Remote
Procedure Call (RPC) Locator and Procedure Call (RPC) Service.
−
Component: Select the following attributes to be included in the
accounting log files: date, time, type of event, subject identity and
success/failure.
−
Composed TOE: Select the following attributes to be included in the
accounting log files: date, time, type of event, subject identity,
success/failure, event message and process thread.
1631
If the guidance for the composed TOE deviates (is not a refinement) from
that provided for the base component, the evaluator will assess the potential
risks of the modification to the guidance. The evaluator will use the
information available (including that provided in the public domain, the
architectural description of the base component in the public evaluation
report (e.g. certification report), the context of the guidance from the
remainder of the guidance documentation) to identify likely impact of the
modification to the guidance on the SFRs of the composed TOE.
1632
If during the dependent component evaluation the trial installation used the
base component to satisfy the environment requirements of the dependent
component this work unit for the composed TOE is considered to be
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satisfied. If the base component was not used in satisfaction of the work unit
AGD_PRE.1-5 during the dependent component evaluation, the evaluator
will apply the user procedures provided for the composed TOE to prepare the
composed TOE, in accordance with the guidance specified in AGD_PRE.15. This will allow the evaluator to determine that the preparative guidance
provided for the composed TOE is sufficient to prepare the composed TOE
and its operational environment securely.
16.3.1.2.3
Life-cycle
Delivery
1633
If there is a different delivery mechanism used for the delivery of the
composed TOE (i.e. the components are not delivered to the consumer in
accordance with the secure delivery procedures defined and assessed during
the evaluation of the components), the delivery procedures for the composed
TOE will require evaluation against the Delivery (ALC_DEL) requirements
applied during the components evaluations.
1634
The composed TOE may be delivered as an integrated product or may
require the components to be delivered separately.
1635
If the components are delivered separately, the results of the delivery of the
base component and dependent component are reused. The delivery of the
base component is checked during the evaluator trial installation of the
dependent component, using the specified guidance and checking the aspects
of delivery that are the responsibility of the user, as described in the guidance
documentation for the base component.
1636
If the composed TOE is delivered as a new entity, then the method of
delivery of that entity must be considered in the composed TOE evaluation
activities.
1637
The assessment of the delivery procedures for composed TOE items is to be
performed in accordance with the methodology for Delivery (ALC_DEL) as
for any other [component] TOE, ensuring any additional items (e.g.
additional guidance documents for the composed TOE) are considered in the
delivery procedures.
CM Capabilities
1638
The unique identification of the composed TOE is considered during the
application of Evaluation of sub-activity (ALC_CMC.1) and the items from
which that composed TOE is comprised are considered during the
application of Evaluation of sub-activity (ALC_CMS.2).
1639
Although additional guidance may be produced for the composed TOE, the
unique identification of this guidance (considered as part of the unique
identification of the composed TOE during Evaluation of sub-activity
(ALC_CMC.1)) is considered sufficient control of the guidance.
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1640
The verdicts of the remaining (not considered above) Class ALC: Life-cycle
support activities can be reused from the base component evaluation, as no
further development is performed during integration of the composed TOE.
1641
There are no additional considerations for development security as the
integration is assumed to take place at either the consumer's site or, in the
instance that the composed TOE is delivered as an integrated product, at the
site of the dependent component developer. Control at the consumer's site is
outside the consideration of the CC. No additional requirements or guidance
are necessary if integration is at the same site as that for the dependent
component, as all components are considered to be configuration items for
the composed TOE, and should therefore be considered under the dependent
component developer's security procedures anyway.
1642
Tools and techniques adopted during integration will be considered in the
evidence provided by the dependent component developer. Any
tools/techniques relevant to the base component will have been considered
during the evaluation of the base component. For example, if the base
component is delivered as source code and requires compilation by the
consumer (e.g. dependent component developer who is performing
integration) the compiler would have been specified and assessed, along with
the appropriate arguments, during evaluation of the base component.
1643
There is no life-cycle definition applicable to the composed TOE, as no
further development of items is taking place.
1644
The results of flaw remediation for a component are not applicable to the
composed TOE. If flaw remediation is included in the assurance package for
the composed TOE, then the Flaw remediation (ALC_FLR) requirements are
to be applied during the composed TOE evaluation (as for any
augmentation).
16.3.1.2.4
Tests
1645
The composed TOE will have been tested during the conduct of the Class
ATE: Tests activities for evaluation of the dependent component, as the
configurations used for testing of the dependent component should have
included the base component to satisfy the requirements for IT in the
operational environment. If the base component was not used in the testing
of the dependent component for the dependent component evaluation, or the
configuration of either component varied from their evaluated
configurations, then the developer testing performed for evaluation of the
dependent component to satisfy the Class ATE: Tests requirements is to be
repeated on the composed TOE.
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16.4
Development evidence (ACO_DEV)
16.4.1
Evaluation of sub-activity (ACO_DEV.1)
16.4.1.1
Objectives
1646
The objective of this sub-activity is to determine that the appropriate security
functionality is provided by the base component to support the dependent
component. This is achieved through examination of the interfaces of the
base component to determine that they are consistent with the interfaces
specified in the reliance information; those required by the dependent
component.
1647
The description of the interfaces into the base component is to be provided at
a level of detail consistent with Evaluation of sub-activity (ADV_FSP.2)
although not all of the aspects necessary for satisfaction of Evaluation of
sub-activity (ADV_FSP.2) are required for Evaluation of sub-activity
(ACO_DEV.1), as once the interface has been identified and the purpose
described the remaining detail of the interface specification can be reused
from evaluation of the base component.
16.4.1.2
Input
1648
The evaluation evidence for this sub-activity is:
a)
the composed ST;
b)
the development information;
c)
the reliance information.
16.4.1.3
Action ACO_DEV.1.1E
ACO_DEV.1.1C
The development information shall describe the purpose of each interface
of the base component used in the composed TOE.
ACO_DEV.1-1
The evaluator shall examine the development information to determine that
it describes the purpose of each interface.
1649
The base component provides interfaces to support interaction with the
dependent component in the provision of the dependent TSF. The purpose of
each interface is to be described at the same level as the description of the
interfaces to the dependent component TSF functionality, as would be
provided between subsystems in the TOE design (Evaluation of sub-activity
(ADV_TDS.1)). This description is to provide the reader with an
understanding of how the base component provides the services required by
the dependent component TSF.
1650
This work unit may be satisfied by the provision of the functional
specification for the base component for those interfaces that are TSFIs of
the base component.
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ACO_DEV.1.2C
The development information shall show correspondence between the
interfaces, used in the composed TOE, of the base component and the
dependent component to support the TSF of the dependent component.
ACO_DEV.1-2
The evaluator shall examine the development information to determine the
correspondence, between the interfaces of the base component and the
interfaces on which the dependent component relies, is accurate.
1651
The correspondence between the interfaces of the base component and the
interfaces on which the dependent component relies may take the form of a
matrix or table. The interfaces that are relied upon by the dependent
component are identified in the reliance information (as examined during
Reliance of dependent component (ACO_REL) activity).
1652
There is, during this activity, no requirement to determine completeness of
the coverage of interfaces that are relied upon by the dependent component,
only that the correspondence is correct and ensuring that interfaces of the
base component are mapped to interfaces required by the dependent
component wherever possible. The completeness of the coverage is
considered in Composition rationale (ACO_COR) activities.
16.4.1.4
Action ACO_DEV.1.2E
ACO_DEV.1-3
The evaluator shall examine the development information and the reliance
information to determine that the interfaces are described consistently.
1653
The evaluator's goal in this work unit is to determine that the interfaces
described in the development information for the base component and the
reliance information for the dependent component are represented
consistently.
16.4.2
Evaluation of sub-activity (ACO_DEV.2)
16.4.2.1
Objectives
1654
The objective of this sub-activity is to determine that the appropriate security
functionality is provided by the base component to support the dependent
component. This is achieved through examination of the interfaces and
associated security behaviour of the base component to determine that they
are consistent with the interfaces specified in the reliance information; those
required by the dependent component.
16.4.2.2
Input
1655
The evaluation evidence for this sub-activity is:
a)
the composed ST;
b)
the development information;
c)
reliance information.
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16.4.2.3
Action ACO_DEV.2.1E
ACO_DEV.2.1C
The development information shall describe the purpose and method of use
of each interface of the base component used in the composed TOE.
ACO_DEV.2-1
The evaluator shall examine the development information to determine that
it describes the purpose of each interface.
1656
The base component provides interfaces to support interaction with the
dependent component in the provision of the dependent TSF. The purpose of
each interface is to be described at the same level as the description of the
interfaces to the dependent component TSF functionality, as would be
provided between subsystems in the TOE design (Evaluation of sub-activity
(ADV_TDS.1)). This description is to provide the reader with an
understanding of how the base component provides the services required by
the dependent component TSF.
1657
This work unit may be satisfied by the provision of the functional
specification for the base component for those interfaces that are TSFIs of
the base component.
ACO_DEV.2-2
The evaluator shall examine the development information to determine that
it describes the method of use for each interface.
1658
The method of use for an interface summarises how the interface is
manipulated in order to invoke the operations and obtain results associated
with the interface. The evaluator should be able to determine from reading
this material in the development information how to use each interface. This
does not necessarily mean that there needs to be a separate method of use for
each interface, as it may be possible to describe in general how APIs are
invoked, for instance, and then identify each interface using that general
style.
1659
This work unit may be satisfied by the provision of the functional
specification for the base component for those interfaces that are TSFIs of
the base component.
ACO_DEV.2.2C
The development information shall provide a high-level description of the
behaviour of the base component, which supports the enforcement of the
dependent component SFRs.
ACO_DEV.2-3
The evaluator shall examine the development information to determine that
it describes the behaviour of the base component that supports the
enforcement of the dependent component SFRs.
1660
The dependent component invokes interfaces of the base component for the
provision of services by the base component. For the interfaces of the base
component that are invoked, the development information shall provide a
high-level description of the associated security behaviour of the base
component. The description of the base component security behaviour will
outline how the base component provides the necessary service when the call
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to the interface is made. This description is to be at a level similar to that
provided for ADV_TDS.1.4C. Therefore, the provision of the TOE design
evidence from the base component evaluation would satisfy this work unit,
where the interfaces invoked by the dependent component are TSFI of the
base component. If the interfaces invoked by the dependent component are
not TSFIs of the base component it is the associated security behaviour will
not necessarily be described in the base component TOE design evidence.
ACO_DEV.2.3C
The development information shall show correspondence between the
interfaces, used in the composed TOE, of the base component and the
dependent component to support the TSF of the dependent component.
ACO_DEV.2-4
The evaluator shall examine the development information to determine the
correspondence, between the interfaces of the base component and the
interfaces on which the dependent component relies, is accurate.
1661
The correspondence between the interfaces of the base component and the
interfaces on which the dependent component relies may take the form of a
matrix or table. The interfaces that are relied upon by the dependent
component are identified in the reliance information (as examined during
Reliance of dependent component (ACO_REL)).
1662
There is, during this activity, no requirement to determine completeness of
the coverage of interfaces that are relied upon by the dependent component,
only that the correspondence is correct and ensuring that interfaces of the
base component are mapped to interfaces required by the dependent
component wherever possible. The completeness of the coverage is
considered in Composition rationale (ACO_COR) activities.
16.4.2.4
Action ACO_DEV.2.2E
ACO_DEV.2-5
The evaluator shall examine the development information and the reliance
information to determine that the interfaces are described consistently.
1663
The evaluator's goal in this work unit is to determine that the interfaces
described in the development information for the base component and the
reliance information for the dependent component are represented
consistently.
16.4.3
Evaluation of sub-activity (ACO_DEV.3)
16.4.3.1
Objectives
1664
The objective of this sub-activity is to determine that the appropriate security
functionality is provided by the base component to support the dependent
component. This is achieved through examination of the interfaces and
associated security behaviour of the base component to determine that they
are consistent with the interfaces specified in the reliance information; those
required by the dependent component.
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1665
In addition to the interface description, the subsystems of the base
component that provide the security functionality required by the dependent
component will be described to enable the evaluator to determine whether or
not that interface formed part of the TSF of the base component.
16.4.3.2
Input
1666
The evaluation evidence for this sub-activity is:
a)
the composed ST;
b)
the development information;
c)
reliance information.
16.4.3.3
Action ACO_DEV.3.1E
ACO_DEV.3.1C
The development information shall describe the purpose and method of use
of each interface of the base component used in the composed TOE.
ACO_DEV.3-1
The evaluator shall examine the development information to determine that
it describes the purpose of each interface.
1667
The base component provides interfaces to support interaction with the
dependent component in the provision of the dependent TSF. The purpose of
each interface is to be described at the same level as the description of the
interfaces to the dependent component TSF functionality, as would be
provided between subsystems in the TOE design (Evaluation of sub-activity
(ADV_TDS.1)). This description is to provide the reader with an
understanding of how the base component provides the services required by
the dependent component TSF.
1668
This work unit may be satisfied by the provision of the functional
specification for the base component for those interfaces that are TSFIs of
the base component.
ACO_DEV.3-2
The evaluator shall examine the development information to determine that
it describes the method of use for each interface.
1669
The method of use for an interface summarises how the interface is
manipulated in order to invoke the operations and obtain results associated
with the interface. The evaluator should be able to determine from reading
this material in the development information how to use each interface. This
does not necessarily mean that there needs to be a separate method of use for
each interface, as it may be possible to describe in general how APIs are
invoked, for instance, and then identify each interface using that general
style.
1670
This work unit may be satisfied by the provision of the functional
specification for the base component for those interfaces that are TSFIs of
the base component.
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ACO_DEV.3.2C
The development information shall identify the subsystems of the base
component that provide interfaces of the base component used in the
composed TOE.
ACO_DEV.3-3
The evaluator shall examine the development information to determine that
all subsystems of the base component that provide interfaces to the
dependent component are identified.
1671
For those interfaces that are considered to form part of the TSFI of the base
component, the subsystems associated with the interface will be subsystems
considered in the TOE design (ADV_TDS) activity during the base
component evaluation. The interfaces on which the dependent component
relies that did not form part of the TSFI of the base component will map to
subsystems outside of the base component TSF.
ACO_DEV.3.3C
The development information shall provide a high-level description of the
behaviour of the base component subsystems, which support the
enforcement of the dependent component SFRs.
ACO_DEV.3-4
The evaluator shall examine the development information to determine that
it describes the behaviour of the base component subsystems that support the
enforcement of the dependent component SFRs.
1672
The dependent component invokes interfaces of the base component for the
provision of services by the base component. For the interfaces of the base
component that are invoked, the development information shall provide a
high-level description of the associated security behaviour of the base
component. The description of the base component security behaviour will
outline how the base component provides the necessary service when the call
to the interface is made. This description is to be at a level similar to that
provided for ADV_TDS.1.4C. Therefore, the provision of the TOE design
evidence from the base component evaluation would satisfy this work unit,
where the interfaces invoked by the dependent component are TSFI of the
base component. If the interfaces invoked by the dependent component are
not TSFIs of the base component it is the associated security behaviour will
not necessarily be described in the base component TOE design evidence.
ACO_DEV.3.4C
The development information shall provide a mapping from the interfaces
to the subsystems of the base component.
ACO_DEV.3-5
The evaluator shall examine the development information to determine that
the correspondence between the interfaces and subsystems of the base
component is accurate.
1673
If the TOE design and functional specification evidence from the base
component evaluation is available, this can be used to verify the accuracy of
the correspondence between the interfaces and subsystems of the base
component as used in the composed TOE. Those interfaces of the base
component, which formed part of the base component TSFI will be described
in the base component functional specification, and the associated
subsystems will be described in the base component TOE design evidence.
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The tracing between the two will be provided in the base component TOE
design evidence.
1674
If, however, the base component interface did not form part of the TSFI of
the base component, the description of the subsystem behaviour provided in
the development information will be used to verify the accuracy of the
correspondence.
ACO_DEV.3.5C
The development information shall show correspondence between the
interfaces, used in the composed TOE, of the base component and the
dependent component to support the TSF of the dependent component.
ACO_DEV.3-6
The evaluator shall examine the development information to determine the
correspondence, between the interfaces of the base component and the
interfaces on which the dependent component relies, is accurate.
1675
The correspondence between the interfaces of the base component and the
interfaces on which the dependent component relies may take the form of a
matrix or table. The interfaces that are relied upon by the dependent
component are identified in the reliance information (as examined during
Reliance of dependent component (ACO_REL)).
1676
There is, during this activity, no requirement to determine completeness of
the coverage of interfaces that are relied upon by the dependent component,
only that the correspondence is correct and ensuring that interfaces of the
base component are mapped to interfaces required by the dependent
component wherever possible. The completeness of the coverage is
considered in Composition rationale (ACO_COR) activities.
16.4.3.4
Action ACO_DEV.3.2E
ACO_DEV.3-7
The evaluator shall examine the development information and the reliance
information to determine that the interfaces are described consistently.
1677
The evaluator's goal in this work unit is to determine that the interfaces
described in the development information for the base component and the
reliance information for the dependent component are represented
consistently.
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16.5
Reliance of dependent component (ACO_REL)
16.5.1
Evaluation of sub-activity (ACO_REL.1)
16.5.1.1
Objectives
1678
The objectives of this sub-activity are to determine whether the developer's
reliance evidence provides sufficient information to determine that the
necessary functionality is available in the base component, and the means by
which that functionality is invoked. These are provided in terms of a highlevel description.
16.5.1.2
Input
1679
The evaluation evidence for this sub-activity is:
a)
the composed ST;
b)
the dependent component functional specification;
c)
the dependent component design;
d)
the dependent component architectural design;
e)
the reliance information.
16.5.1.3
Application notes
1680
A dependent component whose TSF interacts with the base component
requires functionality provided by that base component (e.g., remote
authentication, remote audit data storage). In these cases, those invoked
services need to be described for those charged with configuring the
composed TOE for end users. The rationale for requiring this documentation
is to aid integrators of the composed TOE to determine what services in the
base component might have adverse effects on the dependent component,
and to provide information against which to determine the compatibility of
the components when applying the Development evidence (ACO_DEV)
family.
16.5.1.4
Action ACO_REL.1.1E
ACO_REL.1.1C
The reliance information shall describe the functionality of the base
component hardware, firmware and/or software that is relied upon by the
dependent component TSF.
ACO_REL.1-1
The evaluator shall check the reliance information to determine that it
describes the functionality of the base dependent hardware, firmware and/or
software that is relied upon by the dependent component TSF.
1681
The evaluator assesses the description of the security functionality that the
dependent component TSF requires to be provided by the base component's
hardware, firmware and software. The emphasis of this work unit is on the
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level of detail of this description, rather than on an assessment of the
information's accuracy. (The assessment of the accuracy of the information is
the focus of the next work unit.)
1682
This description of the base component's functionality need not be any more
detailed than the level of the description of a component of the TSF, as
would be provided in the TOE Design (TOE design (ADV_TDS))
ACO_REL.1-2
The evaluator shall examine the reliance information to determine that it
accurately reflects the objectives specified for the operational environment of
the dependent component.
1683
The reliance information contains the description of the base component's
security functionality relied upon by the dependent component. To ensure
that the reliance information is consistent with the expectations of the
operational environment of the dependent component, the evaluator
compares the reliance information with the statement of objectives for the
environment in the ST for the dependent component.
1684
For example, if the reliance information claims that the dependent
component TSF relies upon the base component to store and protect audit
data, yet other evaluation evidence (e.g. the dependent component design)
makes it clear that the dependent component TSF itself is storing and
protecting the audit data, this would indicate an inaccuracy.
1685
It should be noted that the objectives for the operational environment may
include objectives that can be met by non-IT measures. While the services
that the base component environment is expected to provide may be
described in the description of IT objectives for the operational environment
in the dependent component ST, it is not required that all such expectations
on the environment be described in the reliance information.
ACO_REL.1.2C
The reliance information shall describe all interactions through which the
dependent component TSF requests services from the base component.
ACO_REL.1-3
The evaluator shall examine the reliance information to determine that it
describes all interactions between the dependent component and the base
component, through which the dependent component TSF requests services
from the base component.
1686
The dependent component TSF may request services of the base component
that were not within the TSF of the base component (see B.3, Interactions
between composed IT entities in CC Part 3).
1687
The interfaces to the base component's functionality are described at the
same level as the description of the interfaces to the dependent component
TSF functionality, as would be provided between subsystems in the TOE
design (Evaluation of sub-activity (ADV_TDS.1)).
1688
The purpose of describing the interactions between the dependent component
and the base component is to provide an understanding of how the dependent
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component TSF relies upon the base component for the provision of services
to support the operation of security functionality of the dependent
component. These interactions do not need to be characterised at the
implementation level (e.g. parameters passed from one routine in a
component to a routine in another component), but the data elements
identified for a particular component that are going to be used by another
component should be covered in this description. The statement should help
the reader understand in general why the interaction is necessary.
1689
Accuracy and completeness of the interfaces is based on the security
functionality that the TSF requires to be provided by the base component, as
assessed in work units ACO_REL.1-1 and ACO_REL.1-2. It should be
possible to map all of the functionality described in the earlier work units to
the interfaces identified in this work unit, and vice versa. An interface that
does not correspond to described functionality would also indicate an
inadequacy.
ACO_REL.1.3C
The reliance information shall describe how the dependent TSF protects
itself from interference and tampering by the base component.
ACO_REL.1-4
The evaluator shall examine the reliance information to determine that it
describes how the dependent TSF protects itself from interference and
tampering by the base component describes the method of use for each
interface.
1690
The description of how the dependent component protects itself from
interference and tampering by the base component is to be provided at the
same level of detail as necessary for ADV_ARC.1-4.
16.5.2
Evaluation of sub-activity (ACO_REL.2)
16.5.2.1
Objectives
1691
The objectives of this sub-activity are to determine whether the developer's
reliance evidence provides sufficient information to determine that the
necessary functionality is available in the base component, and the means by
which that functionality is invoked. This is provided in terms of the
interfaces between the dependent and base component and the return values
from those interfaces called by the dependent component.
16.5.2.2
Input
1692
The evaluation evidence for this sub-activity is:
a)
the composed ST;
b)
the dependent component functional specification;
c)
the dependent component design;
d)
the dependent component implementation representation;
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e)
the dependent component architectural design;
f)
the reliance information.
16.5.2.3
Application notes
1693
A dependent component whose TSF interacts with the base component
requires functionality provided by that base component (e.g., remote
authentication, remote audit data storage). In these cases, those invoked
services need to be described for those charged with configuring the
composed TOE for end users. The rationale for requiring this documentation
is to aid integrators of the composed TOE to determine what services in the
base component might have adverse effects on the dependent component,
and to provide information against which to determine the compatibility of
the components when applying the Development evidence (ACO_DEV)
family.
16.5.2.4
Action ACO_REL.2.1E
ACO_REL.2.1C
The reliance information shall describe the functionality of the base
component hardware, firmware and/or software that is relied upon by the
dependent component TSF.
ACO_REL.2-1
The evaluator shall check the reliance information to determine that it
describes the functionality of the base dependent hardware, firmware and/or
software that is relied upon by the dependent component TSF.
1694
The evaluator assesses the description of the security functionality that the
dependent component TSF requires to be provided by the base component's
hardware, firmware and software. The emphasis of this work unit is on the
level of detail of this description, rather than on an assessment of the
information's accuracy. (The assessment of the accuracy of the information is
the focus of the next work unit.)
1695
This description of the base component's functionality need not be any more
detailed than the level of the description of a component of the TSF, as
would be provided in the TOE Design (TOE design (ADV_TDS))
ACO_REL.2-2
The evaluator shall examine the reliance information to determine that it
accurately reflects the objectives specified for the operational environment of
the dependent component.
1696
The reliance information contains the description of the base component's
security functionality relied upon by the dependent component. To ensure
that the reliance information is consistent with the expectations of the
operational environment of the dependent component, the evaluator
compares the reliance information with the statement of objectives for the
environment in the ST for the dependent component.
1697
For example, if the reliance information claims that the dependent
component TSF relies upon the base component to store and protect audit
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data, yet other evaluation evidence (e.g. the dependent component design)
makes it clear that the dependent component TSF itself is storing and
protecting the audit data, this would indicate an inaccuracy.
1698
It should be noted that the objectives for the operational environment may
include objectives that can be met by non-IT measures. While the services
that the base component environment is expected to provide may be
described in the description of IT objectives for the operational environment
in the dependent component ST, it is not required that all such expectations
on the environment be described in the reliance information.
ACO_REL.2.2C
The reliance information shall describe all interactions through which the
dependent component TSF requests services from the base component.
ACO_REL.2-3
The evaluator shall examine the reliance information to determine that it
describes all interactions between the dependent component and the base
component, through which the dependent component TSF requests services
from the base component.
1699
The dependent component TSF may request services of the base component
that were not within the TSF of the base component (see Annex B.3,
Interactions between composed IT entities in CC Part 3).
1700
The interfaces to the base component's functionality are described at the
same level as the description of the interfaces to the dependent component
TSF functionality, as would be provided between subsystems in the TOE
design (Evaluation of sub-activity (ADV_TDS.1)).
1701
The purpose of describing the interactions between the dependent component
and the base component is to provide an understanding of how the dependent
component TSF relies upon the base component for the provision of services
to support the operation of security functionality of the dependent
component. These interactions do not need to be characterised at the
implementation level (e.g. parameters passed from one routine in a
component to a routine in another component), but the data elements
identified for a particular component that are going to be used by another
component should be covered in this description. The statement should help
the reader understand in general why the interaction is necessary.
1702
Accuracy and completeness of the interfaces is based on the security
functionality that the TSF requires to be provided by the base component, as
assessed in work units ACO_REL.2-1 and ACO_REL.2-2. It should be
possible to map all of the functionality described in the earlier work units to
the interfaces identified in this work unit, and vice versa. An interface that
does not correspond to described functionality would also indicate an
inadequacy.
ACO_REL.2.3C
The reliance information shall describe each interaction in terms of the
interface used and the return values from those interfaces.
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ACO_REL.2-4
The reliance information shall describe each interaction in terms of the
interface used and the return values from those interfaces.
1703
The identification of the interfaces used by the dependent component TSF
when making services requests of the base component allows an integrator to
determine whether the base component provides all the necessary
corresponding interfaces. This understanding is further gained through the
specification of the return values expected by the dependent component. The
evaluator ensures that interfaces are described for each interaction specified
(as analysed in ACO_REL.2-3).
ACO_REL.2.4C
The reliance information shall describe how the dependent TSF protects
itself from interference and tampering by the base component.
ACO_REL.2-5
The evaluator shall examine the reliance information to determine that it
describes how the dependent TSF protects itself from interference and
tampering by the base component describes the method of use for each
interface.
1704
The description of how the dependent component protects itself from
interference and tampering by the base component is to be provided at the
same level of detail as necessary for ADV_ARC.1-4.
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16.6
Composed TOE testing (ACO_CTT)
16.6.1
Evaluation of sub-activity (ACO_CTT.1)
16.6.1.1
Objectives
1705
The objective of this sub-activity is to determine whether the developer
correctly performed and documented tests for each of the base component
interfaces on which the dependent component relies. As part of this
determination the evaluator repeats a sample of the tests performed by the
developer and performs any additional tests required to ensure the expected
behaviour of all composed TOE SFRs and interfaces of the base component
relied upon by the dependent component is demonstrated.
16.6.1.2
Input
1706
The evaluation evidence for this sub-activity is:
a)
the composed TOE suitable for testing;
b)
the composed TOE testing evidence;
c)
the reliance information;
d)
the development information.
16.6.1.3
Action ACO_CTT.1.1E
ACO_CTT.1.1C
The composed TOE and base component interface test documentation
shall consist of test plans, expected test results and actual test results.
ACO_CTT.1-1
The evaluator shall examine the composed TOE test documentation to
determine that it consists of test plans, expected test results and actual test
results.
1707
This work unit may be satisfied by provision of the test evidence from the
evaluation of the dependent component if the base component was used to
satisfy the requirements for IT in the operational environment of the
dependent component.
1708
All work units necessary for the satisfaction of ATE_FUN.1.1E will be
applied to determine:
a)
that the test documentation consist of test plans expected test results
and actual test results;
b)
that the test documentation contains the information necessary to
ensure the tests are repeatable;
c)
the level of developer effort that was applied to testing of the base
component.
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ACO_CTT.1-2
The evaluator shall examine the base component interface test
documentation to determine that it consists of test plans, expected test results
and actual test results.
1709
This work unit may be satisfied by provision of the test evidence from the
evaluation of the base component for those interfaces relied upon in the
composed TOE by the dependent component are TSFIs of the successfully
evaluated base component. The determination of whether the interfaces of
the base component relied upon by the dependent component were in fact
TSFIs of the evaluated base component is made during the ACO_COR
activity.
1710
All work units necessary for the satisfaction of ATE_FUN.1.1E will be
applied to determine:
a)
that the test documentation consist of test plans expected test results
and actual test results;
b)
that the test documentation contains the information necessary to
ensure the tests are repeatable;
c)
the level of developer effort that was applied to testing of the base
component.
ACO_CTT.1.2C
The test documentation from the developer execution of the composed
TOE tests shall demonstrate that the TSF behaves as specified.
ACO_CTT.1-3
The evaluator shall examine the test documentation to determine that the
developer execution of the composed TOE tests shall demonstrate that the
TSF behaves as specified.
1711
The evaluator should construct a mapping between the tests described in the
test plan and the SFRs specified for the composed TOE to identify which
SFRs have been tested by the developer.
1712
Guidance on this work unit can be found in:
a)
Chapter 14.2.1.
b)
Chapter 14.2.2.
1713
The outputs from the successful execution of the tests (as assessed for
ATE_FUN.1.3C can be compared with the mapping to determine that the
SFRs of the composed TOE, as tested by the developer, behave as expected.
ACO_CTT.1.3C
The test documentation from the developer execution of the base
component interface tests shall demonstrate that the base component
interface relied upon by the dependent component behaves as specified.
ACO_CTT.1-4
The evaluator shall examine the test documentation to determine that the
developer execution of the base component interface tests shall demonstrate
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that the base component interfaces relied upon by the dependent component
behave as specified.
1714
The evaluator should construct a mapping between the tests described in the
test plan and the interfaces of the base component relied upon by the
dependent component (as specified in the reliance information, examined
under ACO_REL) to identify which base component interfaces have been
tested by the developer.
1715
Guidance on this work unit can be found in:
a)
Chapter 14.2.1.
b)
Chapter 14.2.2.
1716
The outputs from the successful execution of the tests (as assessed for
ATE_FUN.1.3C can be compared with the mapping to determine that the
interfaces of the base component, as tested by the developer, behave as
expected.
ACO_CTT.1.4C
The base component shall be suitable for testing.
ACO_CTT.1-5
The evaluator shall examine the composed TOE to determine that it has
been installed properly and is in a known state.
1717
To determine that the composed TOE has been installed properly and is in a
known state the ATE_IND.2-1 and ATE_IND.2-2 work units will be applied
to the TOE provided by the developer for testing.
ACO_CTT.1-6
The evaluator shall examine the set of resources provided by the developer
to determine that they are equivalent to the set of resources used by the base
component developer to functionally test the base component.
1718
To determine that the set of resources provided are equivalent to those used
to functionally test the base component as used in the composed TOE, the
ATE_IND.2-3 work unit will be applied.
16.6.1.4
Action ACO_CTT.1.2E
ACO_CTT.1-7
The tests are to be selected and executed in accordance with ATE_IND.2.2E,
to demonstrate the correct behaviour of the SFRs specified in the composed
TOE security target.
1719
The evaluator will apply all work units necessary for the satisfaction of
ATE_IND.2.2E, reporting in the ETR for the composed TOE all analysis,
results and verdicts as dictated by the associated work units.
16.6.1.5
Action ACO_CTT.1.3E
ACO_CTT.1-8
The evaluator shall perform testing, in accordance with ATE_IND.2.3E, for
a subset of the SFRs specified in the composed TOE security target to
operate as specified.
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1720
The evaluator will apply all work units necessary for the satisfaction of
ATE_IND.2.3E, reporting in the ETR for the composed TOE all analysis,
results and verdicts as dictated by the work units.
1721
When selecting interfaces of the TSF of the composed TOE to test, the
evaluator should take into account any modifications to the components from
the evaluated version or configuration. Modifications to the component from
that evaluated may include patches introduced, a different configuration as a
result of modified guidance documentation, reliance an additional portion of
the component that was not within the TSF of the component. These
modifications will have been identified during the Composition rationale
(ACO_COR) activity.
16.6.2
Evaluation of sub-activity (ACO_CTT.2)
16.6.2.1
Objectives
1722
The objective of this sub-activity is to determine whether the developer
correctly performed and documented tests for each of the base component
interfaces on which the dependent component relies. As part of this
determination the evaluator repeats a sample of the tests performed by the
developer and performs any additional tests required to fully demonstrate the
expected behaviour of the composed TOE and the interfaces of the base
component relied upon by the dependent component.
16.6.2.2
Input
1723
The evaluation evidence for this sub-activity is:
a)
the composed TOE suitable for testing;
b)
the composed TOE testing evidence;
c)
the reliance information;
d)
the development information.
16.6.2.3
Action ACO_CTT.2.1E
ACO_CTT.2.1C
The composed TOE and base component interface test documentation
shall consist of test plans, expected test results and actual test results.
ACO_CTT.2-1
The evaluator shall examine the composed TOE test documentation to
determine that it consists of test plans, expected test results and actual test
results.
1724
This work unit may be satisfied by provision of the test evidence from the
evaluation of the dependent component if the base component was used to
satisfy the requirements for IT in the operational environment of the
dependent component.
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1725
All work units necessary for the satisfaction of ATE_FUN.1.1E will be
applied to determine:
a)
that the test documentation consist of test plans expected test results
and actual test results;
b)
that the test documentation contains the information necessary to
ensure the tests are repeatable;
c)
the level of developer effort that was applied to testing of the base
component.
ACO_CTT.2-2
The evaluator shall examine the base component interface test
documentation to determine that it consists of test plans, expected test results
and actual test results.
1726
This work unit may be satisfied by provision of the test evidence from the
evaluation of the base component for those interfaces relied upon in the
composed TOE by the dependent component are TSFIs of the successfully
evaluated base component. The determination of whether the interfaces of
the base component relied upon by the dependent component were in fact
TSFIs of the evaluated base component is made during the ACO_COR
activity.
1727
All work units necessary for the satisfaction of ATE_FUN.1.1E will be
applied to determine:
a)
that the test documentation consist of test plans expected test results
and actual test results;
b)
that the test documentation contains the information necessary to
ensure the tests are repeatable;
c)
the level of developer effort that was applied to testing of the base
component.
ACO_CTT.2.2C
The test documentation from the developer execution of the composed
TOE tests shall demonstrate that the TSF behaves as specified and is
complete.
ACO_CTT.2-3
The evaluator shall examine the test documentation to determine that it
provides accurate correspondence between the tests in the test documentation
relating to the testing of the composed TOE and the composed TOE SFRs in
the composed TOE security target.
1728
A simple cross-table may be sufficient to show test correspondence. The
identification of correspondence between the tests and SFRs presented in the
test documentation has to be unambiguous.
ACO_CTT.2-4
The evaluator shall examine the test documentation to determine that the
developer execution of the composed TOE tests shall demonstrate that the
TSF behaves as specified.
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1729
Guidance on this work unit can be found in:
a)
Chapter 14.2.1.
b)
Chapter 14.2.2.
1730
The outputs from the successful execution of the tests (as assessed for
ATE_FUN.1.3C can be compared with the mapping to determine that the
SFRs of the composed TOE, as tested by the developer, behave as expected.
ACO_CTT.2.3C
The test documentation from the developer execution of the base
component interface tests shall demonstrate that the base component
interface relied upon by the dependent component behaves as specified and
is complete.
ACO_CTT.2-5
The evaluator shall examine the test documentation to determine that it
provides accurate correspondence between the tests in the test documentation
relating to the testing of the base component interfaces relied upon by the
dependent component and the interfaces specified in the reliance
information.
1731
A simple cross-table may be sufficient to show test correspondence. The
identification of correspondence between the tests and interfaces presented in
the test documentation has to be unambiguous.
ACO_CTT.2-6
The evaluator shall examine the test documentation to determine that the
developer execution of the base component interface tests shall demonstrate
that the base component interfaces relied upon by the dependent component
behave as specified.
1732
Guidance on this work unit can be found in:
a)
Chapter 14.2.1.
b)
Chapter 14.2.2.
1733
The outputs from the successful execution of the tests (as assessed for
ATE_FUN.1.3C can be compared with the mapping to determine that the
interfaces of the base component, as tested by the developer, behave as
expected.
ACO_CTT.2.4C
The base component shall be suitable for testing.
ACO_CTT.2-7
The evaluator shall examine the composed TOE to determine that it has
been installed properly and is in a known state.
1734
To determine that the composed TOE has been installed properly and is in a
known state the ATE_IND.2-1 and ATE_IND.2-2 work units will be applied
to the TOE provided by the developer for testing.
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ACO_CTT.2-8
The evaluator shall examine the set of resources provided by the developer
to determine that they are equivalent to the set of resources used by the base
component developer to functionally test the base component.
1735
To determine that the set of resources provided are equivalent to those used
to functionally test the base component as used in the composed TOE, the
ATE_IND.2-3 work unit will be applied.
16.6.2.4
Action ACO_CTT.2.2E
ACO_CTT.2-9
The tests are to be selected and executed in accordance with ATE_IND.2.2E,
to demonstrate the correct behaviour of the SFRs specified in the composed
TOE security target.
1736
The evaluator will apply all work units necessary for the satisfaction of
ATE_IND.2.2E, reporting in the ETR for the composed TOE all analysis,
results and verdicts as dictated by the associated work units.
16.6.2.5
Action ACO_CTT.2.3E
ACO_CTT.2-10
The evaluator shall perform testing, in accordance with ATE_IND.2.3E, for
a subset of the SFRs specified in the composed TOE security target to
operate as specified.
1737
The evaluator will apply all work units necessary for the satisfaction of
ATE_IND.2.3E, reporting in the ETR for the composed TOE all analysis,
results and verdicts as dictated by the work units.
1738
When selecting interfaces of the TSF of the composed TOE to test, the
evaluator should take into account any modifications to the components from
the evaluated version or configuration. Modifications to the component from
that evaluated may include patches introduced, a different configuration as a
result of modified guidance documentation, reliance an additional portion of
the component that was not within the TSF of the component. These
modifications will have been identified during the Composition rationale
(ACO_COR) activity.
ACO_CTT.2-11
The evaluator shall perform testing, in accordance with Evaluation of subactivity (ATE_IND.2), for a subset of the interfaces to the base component to
confirm they operate as specified.
1739
The evaluator will apply all work units necessary for the satisfaction of
ATE_IND.2.3E, reporting in the ETR for the composed TOE all analysis,
results and verdicts as dictated by the work units.
1740
When selecting interfaces of the base component to test, the evaluator should
take into account any modifications to the base component from the
evaluated version or configuration. In particular, the evaluator should
consider the development of tests to demonstrate the correct behaviour of
interfaces of the base component that were not considered during the
evaluation of the base component. These additional interfaces and other
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modifications to the base component will have been identified during the
Composition rationale (ACO_COR) activity.
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16.7
Composition vulnerability analysis (ACO_VUL)
16.7.1
Evaluation of sub-activity (ACO_VUL.1)
16.7.1.1
Objectives
1741
The objective of this sub-activity is to determine whether the composed
TOE, in its operational environment, has easily exploitable vulnerabilities.
1742
The developer provides details of any residual vulnerabilities reported from
evaluation of the components. The evaluator performs an analysis of the
disposition the residual vulnerabilities reported and also performs a search of
the public domain, to identify any new potential vulnerabilities in the
components (i.e. those issues that have been reported in the public domain
since evaluation of the base component). The evaluator then performs
penetration testing to demonstrate that the potential vulnerabilities cannot be
exploited in the TOE, in its operational environment, by an attacker with
basic attack potential.
16.7.1.2
Input
1743
The evaluation evidence for this sub-activity is:
a)
the composed TOE suitable for testing;
b)
the composed ST;
c)
the composition rationale;
d)
the guidance documentation;
e)
information publicly available to support the identification of
possible security vulnerabilities;
f)
residual vulnerabilities
component.
reported
during
evaluation
of
each
16.7.1.3
Application notes
1744
See the application notes for Evaluation of sub-activity (AVA_VAN.1).
16.7.1.4
Action ACO_VUL.1.1E
ACO_VUL.1.1C
The composed TOE shall be suitable for testing.
ACO_VUL.1-1
The evaluator shall examine the composed TOE to determine that it has
been installed properly and is in a known state.
1745
To determine that the composed TOE has been installed properly and is in a
known state the ATE_IND.2-1 and ATE_IND.2-2 work units will be applied
to the composed TOE.
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1746
If the assurance package includes a component from the ACO_CTT family,
then the evaluator may refer to the result of the work unit ACO_CTT*-1 to
demonstrate this has been satisfied.
ACO_VUL.1-2
The evaluator shall examine the composed TOE configuration to determine
that any assumptions and objectives in the STs the components relating to IT
entities for are fulfilled by the other components.
1747
The STs for the component may include assumptions about other
components that may use the component to which the ST relates, e.g. the ST
for an operating system used as a base component may include an
assumption that any applications loaded on the operating system do not run
in privileged mode. These assumptions and objectives are to be fulfilled by
other components in the composed TOE.
16.7.1.5
Action ACO_VUL.1.2E
ACO_VUL.1-3
The evaluator shall examine the residual vulnerabilities from the base
component evaluation to determine that they are not exploitable in the
composed TOE in its operational environment.
1748
The list of vulnerabilities identified in the product during the evaluation of
the base component, which were demonstrated to be non-exploitable in the
base component, is to be used as an input into this activity. The evaluator
will determine that the premise(s) on which a vulnerability was deemed to be
non-exploitable is upheld in the composed TOE, or whether the combination
has re-introduced the potential vulnerability. For example, if during
evaluation of the base component it was assumed that a particular operating
system service was disabled, which is enabled in the composed TOE
evaluation, any potential vulnerabilities relating to that service previously
scoped out should now be considered.
1749
Also, this list of known, non-exploitable vulnerabilities resulting from the
evaluation of the base component should be considered in the light of any
known, non-exploitable vulnerabilities for the other components (e.g.
dependent component) within the composed TOE. This is to consider the
case where a potential vulnerability that is non-exploitable in isolation is
exploitable when integrated with an IT entity containing another potential
vulnerability.
ACO_VUL.1-4
The evaluator shall examine the residual vulnerabilities from the dependent
component evaluation to determine that they are not exploitable in the
composed TOE in its operational environment.
1750
The list of vulnerabilities identified in the product during the evaluation of
the dependent component, which were demonstrated to be non-exploitable in
the dependent component, is to be used as an input into this activity. The
evaluator will determine that the premise(s) on which a vulnerability was
deemed to be non-exploitable is upheld in the composed TOE, or whether the
combination has re-introduced the potential vulnerability. For example, if
during evaluation of the dependent component it was assumed that IT
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meeting the operational environment requirements would not return a certain
value in response to a service request, which is provided by the base
component in the composed TOE evaluation, any potential vulnerabilities
relating to that return value previously scoped out should now be considered.
1751
Also, this list of known, non-exploitable vulnerabilities resulting from the
evaluation of the dependent component should be considered in the light of
any known, non-exploitable vulnerabilities for the other components (e.g.
base component) within the composed TOE. This is to consider the case
where a potential vulnerability that is non-exploitable in isolation is
exploitable when integrated with an IT entity containing another potential
vulnerability.
16.7.1.6
Action ACO_VUL.1.3E
ACO_VUL.1-5
The evaluator shall examine the sources of information publicly available to
support the identification of possible security vulnerabilities in the base
component that have become known since the completion of evaluation of
the base component.
1752
The evaluator will use the information in the public domain as described in
AVA_VAN.1-2 to search for vulnerabilities in the base component.
1753
Those potential vulnerabilities that were publicly available prior to the
evaluation of the base component do not have to be further investigated
unless it is apparent to the evaluator that the attack potential required by an
attacker to exploit the potential vulnerability has been significantly reduced.
This may be through the introduction of some new technology since the base
component evaluation that means the exploitation of the potential
vulnerability has been simplified.
ACO_VUL.1-6
The evaluator shall examine the sources of information publicly available to
support the identification of possible security vulnerabilities in the dependent
component that have become known since the completion of the dependent
component evaluation.
1754
The evaluator will use the information in the public domain as described in
AVA_VAN.1-2 to search for vulnerabilities in the dependent component.
1755
Those potential vulnerabilities that were publicly available prior to the
evaluation of the dependent component do not have to be further investigated
unless it is apparent to the evaluator that the attack potential required by an
attacker to exploit the potential vulnerability has been significantly reduced.
This may be through the introduction of some new technology since
evaluation of the dependent component that means the exploitation of the
potential vulnerability has been simplified.
ACO_VUL.1-7
The evaluator shall record in the ETR the identified potential security
vulnerabilities that are candidates for testing and applicable to the composed
TOE in its operational environment.
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1756
The ST, guidance documentation and functional specification are used to
determine whether the vulnerabilities are relevant to the composed TOE in
its operational environment.
1757
The evaluator records any reasons for exclusion of vulnerabilities from
further consideration if the evaluator determines that the vulnerability is not
applicable in the operational environment. Otherwise the evaluator records
the potential vulnerability for further consideration.
1758
A list of potential vulnerabilities applicable to the composed TOE in its
operational environment, which can be used as an input into penetration
testing activities (i.e. ACO_VUL.1.4E), shall be reported in the ETR by the
evaluators.
16.7.1.7
Action ACO_VUL.1.4E
ACO_VUL.1-8
The evaluator shall
AVA_VAN.1.3E.
1759
The evaluator will apply all work units necessary for the satisfaction of
evaluator action AVA_VAN.1.3E, reporting in the ETR for the composed
TOE all analysis and verdicts as dictated by the work units.
1760
The evaluator will also apply the work units for the evaluator action
AVA_VAN.1.1E to determine that the composed TOE provided by the
developer is suitable for testing.
16.7.2
Evaluation of sub-activity (ACO_VUL.2)
16.7.2.1
Objectives
1761
The objective of this sub-activity is to determine whether the composed
TOE, in its operational environment, has vulnerabilities exploitable by
attackers possessing basic attack potential.
1762
The developer provides an analysis of the disposition of any residual
vulnerabilities reported for the components and of any vulnerabilities
introduced through the combination of the base and dependent components.
The evaluator performs a search of the public domain to identify any new
potential vulnerabilities in the components (i.e. those issues that have been
reported in the public domain since the completion of the evaluation of the
components). The evaluator will also perform an independent vulnerability
analysis of the composed TOE and penetration testing.
16.7.2.2
Input
1763
The evaluation evidence for this sub-activity is:
conduct
penetration
a)
the composed TOE suitable for testing;
b)
the composed ST;
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as
detailed
for
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c)
the composition rationale;
d)
the reliance information;
e)
the guidance documentation;
f)
information publicly available to support the identification of
possible security vulnerabilities.
g)
residual vulnerabilities
component.
reported
during
evaluation
of
each
16.7.2.3
Application notes
1764
See the application notes for Evaluation of sub-activity (AVA_VAN.2).
16.7.2.4
Action ACO_VUL.2.1E
ACO_VUL.2.1C
The composed TOE shall be suitable for testing.
ACO_VUL.2-1
The evaluator shall examine the composed TOE to determine that it has
been installed properly and is in a known state.
1765
To determine that the composed TOE has been installed properly and is in a
known state the ATE_IND.2-1 and ATE_IND.2-2 work units will be applied
to the composed TOE.
1766
If the assurance package includes ACO_CTT family, then the evaluator may
refer to the result of the work unit Composed TOE testing (ACO_CTT)*-1 to
demonstrate this has been satisfied.
ACO_VUL.2-2
The evaluator shall examine the composed TOE configuration to determine
that any assumptions and objectives in the STs the components relating to IT
entities for are fulfilled by the other components.
1767
The STs for the component may include assumptions about other
components that may use the component to which the ST relates, e.g. the ST
for an operating system used as a base component may include an
assumption that any applications loaded on the operating system do not run
in privileged mode. These assumptions and objectives are to be fulfilled by
other components in the composed TOE.
16.7.2.5
Action ACO_VUL.2.2E
ACO_VUL.2-3
The evaluator shall examine the residual vulnerabilities from the base
component evaluation to determine that they are not exploitable in the
composed TOE in its operational environment.
1768
The list of vulnerabilities identified in the product during the evaluation of
the base component, which were demonstrated to be non-exploitable in the
base component, is to be used as an input into this activity. The evaluator
will determine that the premise(s) on which a vulnerability was deemed to be
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non-exploitable is upheld in the composed TOE, or whether the combination
has re-introduced the potential vulnerability. For example, if during
evaluation of the base component it was assumed that a particular operating
system service was disabled, which is enabled in the composed TOE
evaluation, any potential vulnerabilities relating to that service previously
scoped out should now be considered.
1769
Also, this list of known, non-exploitable vulnerabilities resulting from the
evaluation of the base component should be considered in the light of any
known, non-exploitable vulnerabilities for the other components (e.g.
dependent component) within the composed TOE. This is to consider the
case where a potential vulnerability that is non-exploitable in isolation is
exploitable when integrated with an IT entity containing another potential
vulnerability.
ACO_VUL.2-4
The evaluator shall examine the residual vulnerabilities from the dependent
component evaluation to determine that they are not exploitable in the
composed TOE in its operational environment.
1770
The list of vulnerabilities identified in the product during the evaluation of
the dependent component, which were demonstrated to be non-exploitable in
the dependent component, is to be used as an input into this activity. The
evaluator will determine that the premise(s) on which a vulnerability was
deemed to be non-exploitable is upheld in the composed TOE, or whether the
combination has re-introduced the potential vulnerability. For example, if
during evaluation of the dependent component it was assumed that IT
meeting the operational environment requirements would not return a certain
value in response to a service request, which is provided by the base
component in the composed TOE evaluation, any potential vulnerabilities
relating to that return value previously scoped out should now be considered.
1771
Also, this list of known, non-exploitable vulnerabilities resulting from the
evaluation of the dependent component should be considered in the light of
any known, non-exploitable vulnerabilities for the other components (e.g.
base component) within the composed TOE. This is to consider the case
where a potential vulnerability that is non-exploitable in isolation is
exploitable when integrated with an IT entity containing another potential
vulnerability.
16.7.2.6
Action ACO_VUL.2.3E
ACO_VUL.2-5
The evaluator examines the sources of information publicly available to
support the identification of possible security vulnerabilities in the base
component that have become known since the completion of the base
component evaluation.
1772
The evaluator will use the information in the public domain as described in
AVA_VAN.2-2 to search for vulnerabilities in the base component.
1773
Those potential vulnerabilities that were publicly available prior to the
evaluation of the base component do not have to be further investigated
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unless it is apparent to the evaluator that the attack potential required by an
attacker to exploit the potential vulnerability has been significantly reduced.
This may be through the introduction of some new technology since the base
component evaluation that means the exploitation of the potential
vulnerability has been simplified.
ACO_VUL.2-6
The evaluator shall examine the sources of information publicly available to
support the identification of possible security vulnerabilities in the dependent
component that have become known since the completion of the dependent
component evaluation.
1774
The evaluator will use the information in the public domain as described in
AVA_VAN.1-2 to search for vulnerabilities in the dependent component.
1775
Those potential vulnerabilities that were publicly available prior to the
evaluation of the dependent component do not have to be further investigated
unless it is apparent to the evaluator that the attack potential required by an
attacker to exploit the potential vulnerability has been significantly reduced.
This may be through the introduction of some new technology since
evaluation of the dependent component that means the exploitation of the
potential vulnerability has been simplified.
ACO_VUL.2-7
The evaluator shall record in the ETR the identified potential security
vulnerabilities that are candidates for testing and applicable to the composed
TOE in its operational environment.
1776
The ST, guidance documentation and functional specification are used to
determine whether the vulnerabilities are relevant to the composed TOE in
its operational environment.
1777
The evaluator records any reasons for exclusion of vulnerabilities from
further consideration if the evaluator determines that the vulnerability is not
applicable in the operational environment. Otherwise the evaluator records
the potential vulnerability for further consideration.
1778
A list of potential vulnerabilities applicable to the composed TOE in its
operational environment, which can be used as an input into penetration
testing activities (ACO_VUL.2.5E), shall be reported in the ETR by the
evaluators.
16.7.2.7
Action ACO_VUL.2.4E
ACO_VUL.2-8
The evaluator shall conduct a search of the composed TOE ST, guidance
documentation, reliance information and composition rationale to identify
possible security vulnerabilities in the composed TOE.
1779
The consideration of the components of the composed TOE in the
independent evaluator vulnerability analysis will take a slightly different
form to that documented in AVA_VAN.2.3E for a component evaluation, as
it will not necessarily consider all layers of design abstraction relevant to the
assurance package. These will have already been considered during the
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evaluation of the components, but the evidence may not be available for the
composed TOE evaluation. However, the general approach described in the
work units associated with AVA_VAN.2.3E is applicable and should form
the basis of the evaluator's search for potential vulnerabilities in the
composed TOE.
1780
A vulnerability analysis of the individual components used in the composed
TOE will have already been performed during evaluation of the individual
components. The focus of the vulnerability analysis during the composed
TOE evaluation is to identify any vulnerabilities introduced as a result of the
integration of the components or due to any changes in the use of the
components between the evaluated component configuration to the
composed TOE configuration.
1781
The evaluator will use the understanding of the component's construction as
detailed in the reliance information for the dependent component, and the
development information and composition rationale for the base component,
together with the dependent component design information. This information
will allow the evaluator to gain an understanding of how the base component
and dependent component interact and identify potential vulnerabilities that
may be introduced as a result of this interaction.
1782
The evaluator will consider any new guidance provided for the installation,
start-up and operation of the composed TOE to identify any potential
vulnerabilities introduced through this revised guidance.
1783
If any of the individual components have been through assurance continuity
activities since the completion of the component evaluation, the evaluator
will consider the patch(es) in the independent vulnerability analysis.
Information related to the change provided in a public report of the assurance
continuity activities (e.g. Maintenance Report) will be the main source of
input material of the change. This will be supplemented by any updates to
the guidance documentation resulting from the change and any information
regarding the change available in the public domain, e.g. vendor website.
1784
Any risks identified due to the lack of evidence to establish the full impact of
any patches or deviations in the configuration of a component from the
evaluated configuration are to be documented in the evaluator's vulnerability
analysis.
16.7.2.8
Action ACO_VUL.2.5E
ACO_VUL.2-9
The evaluator shall
AVA_VAN.2.4E.
1785
The evaluator will apply all work units necessary for the satisfaction of
evaluator action AVA_VAN.2.4E, reporting in the ETR for the composed
TOE all analysis and verdicts as dictated by the work units.
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testing
as
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1786
The evaluator will also apply the work units for the evaluator action
AVA_VAN.2.1E to determine that the composed TOE provided by the
developer is suitable for testing.
16.7.3
Evaluation of sub-activity (ACO_VUL.3)
16.7.3.1
Objectives
1787
The objective of this sub-activity is to determine whether the composed
TOE, in its operational environment, has vulnerabilities exploitable by
attackers possessing extended-basic attack potential.
1788
The developer provides an analysis of the disposition of any residual
vulnerabilities reported for the components and of any vulnerabilities
introduced through the combination of the base and dependent components.
The evaluator performs a search of the public domain to identify any new
potential vulnerabilities in the components (i.e. those issues that have been
reported in the public domain since the completion of the component
evaluations). The evaluator will also perform an independent vulnerability
analysis of the composed TOE and penetration testing.
16.7.3.2
Input
1789
The evaluation evidence for this sub-activity is:
a)
the composed TOE suitable for testing;
b)
the composed ST;
c)
the composition rationale;
d)
the reliance information;
e)
the guidance documentation;
f)
information publicly available to support the identification of
possible security vulnerabilities.
g)
residual vulnerabilities
component.
reported
during
evaluation
of
each
16.7.3.3
Application notes
1790
See the application notes for Evaluation of sub-activity (AVA_VAN.3).
16.7.3.4
Action ACO_VUL.3.1E
ACO_VUL.3.1C
The composed TOE shall be suitable for testing.
ACO_VUL.3-1
The evaluator shall examine the composed TOE to determine that it has
been installed properly and is in a known state.
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1791
To determine that the composed TOE has been installed properly and is in a
known state the ATE_IND.2-1 and ATE_IND.2-2 work units will be applied
to the composed TOE.
1792
If the assurance package includes ACO_CTT family, then the evaluator may
refer to the result of the work unit Composed TOE testing (ACO_CTT)*-1 to
demonstrate this has been satisfied.
ACO_VUL.3-2
The evaluator shall examine the composed TOE configuration to determine
that any assumptions and objectives in the STs the components relating to IT
entities for are fulfilled by the other components.
1793
The STs for the component may include assumptions about other
components that may use the component to which the ST relates, e.g. the ST
for an operating system used as a base component may include an
assumption that any applications loaded on the operating system do not run
in privileged mode. These assumptions and objectives are to be fulfilled by
other components in the composed TOE.
16.7.3.5
Action ACO_VUL.3.2E
ACO_VUL.3-3
The evaluator shall examine the residual vulnerabilities from the base
component evaluation to determine that they are not exploitable in the
composed TOE in its operational environment.
1794
The list of vulnerabilities identified in the product during the evaluation of
the base component, which were demonstrated to be non-exploitable in the
base component, is to be used as an input into this activity. The evaluator
will determine that the premise(s) on which a vulnerability was deemed to be
non-exploitable is upheld in the composed TOE, or whether the combination
has re-introduced the potential vulnerability. For example, if during
evaluation of the base component it was assumed that a particular operating
system service was disabled, which is enabled in the composed TOE
evaluation, any potential vulnerabilities relating to that service previously
scoped out should now be considered.
1795
Also, this list of known, non-exploitable vulnerabilities resulting from the
evaluation of the base component should be considered in the light of any
known, non-exploitable vulnerabilities for the other components (e.g.
dependent component) within the composed TOE. This is to consider the
case where a potential vulnerability that is non-exploitable in isolation is
exploitable when integrated with an IT entity containing another potential
vulnerability.
ACO_VUL.3-4
The evaluator shall examine the residual vulnerabilities from the dependent
component evaluation to determine that they are not exploitable in the
composed TOE in its operational environment.
1796
The list of vulnerabilities identified in the product during the evaluation of
the dependent component, which were demonstrated to be non-exploitable in
the dependent component, is to be used as an input into this activity. The
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evaluator will determine that the premise(s) on which a vulnerability was
deemed to be non-exploitable is upheld in the composed TOE, or whether the
combination has re-introduced the potential vulnerability. For example, if
during evaluation of the dependent component it was assumed that IT
meeting the operational environment requirements would not return a certain
value in response to a service request, which is provided by the base
component in the composed TOE evaluation, any potential vulnerabilities
relating to that return value previously scoped out should now be considered.
1797
Also, this list of known, non-exploitable vulnerabilities resulting from the
evaluation of the dependent component should be considered in the light of
any known, non-exploitable vulnerabilities for the other components (e.g.
base component) within the composed TOE. This is to consider the case
where a potential vulnerability that is non-exploitable in isolation is
exploitable when integrated with an IT entity containing another potential
vulnerability.
16.7.3.6
Action ACO_VUL.3.3E
ACO_VUL.3-5
The evaluator examines the sources of information publicly available to
support the identification of possible security vulnerabilities in the base
component that have become known since the completion of the base
component evaluation.
1798
The evaluator will use the information in the public domain as described in
AVA_VAN.3-2 to search for vulnerabilities in the base component.
1799
Those potential vulnerabilities that were publicly available prior to the
evaluation of the base component do not have to be further investigated
unless it is apparent to the evaluator that the attack potential required by an
attacker to exploit the potential vulnerability has been significantly reduced.
This may be through the introduction of some new technology since the base
component evaluation that means the exploitation of the potential
vulnerability has been simplified.
ACO_VUL.3-6
The evaluator shall examine the sources of information publicly available to
support the identification of possible security vulnerabilities in the dependent
component that have become known since completion of the dependent
component evaluation.
1800
The evaluator will use the information in the public domain as described in
AVA_VAN.1-2 to search for vulnerabilities in the dependent component.
1801
Those potential vulnerabilities that were publicly available prior to the
evaluation of the dependent component do not have to be further investigated
unless it is apparent to the evaluator that the attack potential required by an
attacker to exploit the potential vulnerability has been significantly reduced.
This may be through the introduction of some new technology since
evaluation of the dependent component that means the exploitation of the
potential vulnerability has been simplified.
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Class ACO: Composition
ACO_VUL.3-7
The evaluator shall record in the ETR the identified potential security
vulnerabilities that are candidates for testing and applicable to the composed
TOE in its operational environment.
1802
The ST, guidance documentation and functional specification are used to
determine whether the vulnerabilities are relevant to the composed TOE in
its operational environment.
1803
The evaluator records any reasons for exclusion of vulnerabilities from
further consideration if the evaluator determines that the vulnerability is not
applicable in the operational environment. Otherwise the evaluator records
the potential vulnerability for further consideration.
1804
A list of potential vulnerabilities applicable to the composed TOE in its
operational environment, which can be used as an input into penetration
testing activities (ACO_VUL.3.5E), shall be reported in the ETR by the
evaluators.
16.7.3.7
Action ACO_VUL.3.4E
ACO_VUL.3-8
The evaluator shall conduct a search of the composed TOE ST, guidance
documentation, reliance information and composition rationale to identify
possible security vulnerabilities in the composed TOE.
1805
The consideration of the components in the independent evaluator
vulnerability analysis will take a slightly different form to that documented
in AVA_VAN.3.3E for a component evaluation, as it will not necessarily
consider all layers of design abstraction relevant to the assurance package.
These will have already been considered during the evaluation of the base
component, but the evidence may not be available for the composed TOE
evaluation. However, the general approach described in the work units
associated with AVA_VAN.3.3E is applicable and should form the basis of
the evaluator's search for potential vulnerabilities in the composed TOE.
1806
A vulnerability analysis of the individual components used in the composed
TOE will have already been performed during evaluation of the components.
The focus of the vulnerability analysis during the composed TOE evaluation
is to identify any vulnerabilities introduced as a result of the integration of
the components or due to any changes in the use of the components between
the configuration of the component determined during the component
evaluation and the composed TOE configuration.
1807
The evaluator will use the understanding of the component's construction as
detailed in the reliance information for the dependent component, and the
composition rationale and development information for the base component,
together with the dependent component design information. This information
will allow the evaluator to gain an understanding of how the base component
and dependent component interact.
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1808
The evaluator will consider any new guidance provided for the installation,
start-up and operation of the composed TOE to identify any potential
vulnerabilities introduced through this revised guidance.
1809
If any of the individual components have been through assurance continuity
activities since the completion of the component evaluation, the evaluator
will consider the patch in the independent vulnerability analysis. Information
related to the change provided in a public report of the assurance continuity
activities (e.g. Maintenance Report). This will be supplemented by any
updates to the guidance documentation resulting from the change and any
information regarding the change available in the public domain, e.g. vendor
website.
1810
Any risks identified due to the lack of evidence to establish the full impact of
any patches or deviations in the configuration of a component from the
evaluated configuration are to be documented in the evaluator's vulnerability
analysis.
16.7.3.8
Action ACO_VUL.3.5E
ACO_VUL.3-9
The evaluator shall
AVA_VAN.3.4E.
1811
The evaluator will apply all work units necessary for the satisfaction of
evaluator action AVA_VAN.3.4E, reporting in the ETR for the composed
TOE all analysis and verdicts as dictated by the work units.
1812
The evaluator will also apply the work units for the evaluator action
AVA_VAN.3.1E to determine that the composed TOE provided by the
developer is suitable for testing.
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testing
as
detailed
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A
General evaluation guidance
(normative)
A.1
Objectives
1813
The objective of this chapter is to cover general guidance used to provide
technical evidence of evaluation results. The use of such general guidance
helps in achieving objectivity, repeatability and reproducibility of the work
performed by the evaluator.
A.2
Sampling
1814
This Section provides general guidance on sampling. Specific and detailed
information is given in those work units under the specific evaluator action
elements where sampling has to be performed.
1815
Sampling is a defined procedure of an evaluator whereby some subset of a
required set of evaluation evidence is examined and assumed to be
representative for the entire set. It allows the evaluator to gain enough
confidence in the correctness of particular evaluation evidence without
analysing the whole evidence. The reason for sampling is to conserve
resources while maintaining an adequate level of assurance. Sampling of the
evidence can provide two possible outcomes:
a)
The subset reveals no errors, allowing the evaluator to have some
confidence that the entire set is correct.
b)
The subset reveals errors and therefore the validity of the entire set is
called into question. Even the resolution of all errors that were found
may be insufficient to provide the evaluator the necessary confidence
and as a result the evaluator may have to increase the size of the
subset, or stop using sampling for this particular evidence.
1816
Sampling is a technique which can be used to reach a reliable conclusion if a
set of evidence is relatively homogeneous in nature, e.g. if the evidence has
been produced during a well defined process.
1817
Sampling in the cases identified in the CC, and in cases specifically covered
in CEM work items, is recognised as a cost-effective approach to performing
evaluator actions. Sampling in other areas is permitted only in exceptional
cases, where performance of a particular activity in its entirety would require
effort disproportionate to the other evaluation activities, and where this
would not add correspondingly to assurance. In such cases a rationale for the
use of sampling in that area will need to be made. Neither the fact that the
TOE is large and complex, nor that it has many security functional
requirements, is sufficient justification, since evaluations of large, complex
TOEs can be expected to require more effort. Rather it is intended that this
exception be limited to cases such as that where the TOE development
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approach yields large quantities of material for a particular CC requirement
that would normally all need to be checked or examined, and where such an
action would not be expected to raise assurance correspondingly.
1818
Sampling needs to be justified taking into account the possible impact on the
security objectives and threats of the TOE. The impact depends on what
might be missed as a result of sampling. Consideration also needs to be given
to the nature of the evidence to be sampled, and the requirement not to
diminish or ignore any security functions.
1819
It should be recognised that sampling of evidence directly related to the
implementation of the TOE (e.g. developer test results) requires a different
approach to sampling, then sampling related to the determination of whether
a process is being followed. In many cases the evaluator is required to
determine that a process is being followed, and a sampling strategy is
recommended. The approach for sampling a developer's test results will
differ. This is because the former case is concerned with ensuring that a
process is in place, and the latter deals with determining correct
implementation of the TOE. Typically, larger sample sizes should be
analysed in cases related to the correct implementation of the TOE than
would be necessary to ensure that a process is in place.
1820
In certain cases it may be appropriate for the evaluator to give greater
emphasis to the repetition of developer testing. For example if the
independent tests left for the evaluator to perform would be only
superficially different from those included in an extensive developer test set
(possibly because the developer has performed more testing than necessary
to satisfy the Coverage (ATE_COV) and Depth (ATE_DPT) criteria) then it
would be appropriate for the evaluator to give greater focus to the repetition
of developer tests. Note that this does not necessarily imply a requirement for
a high percentage sample for repetition of developer tests; indeed, given an
extensive developer test set, the evaluator may be able to justify a low
percentage sample.
1821
Where the developer has used an automated test suite to perform functional
testing, it will usually be easier for the evaluator to re-run the entire test suite
rather than repeat only a sample of developer tests. However the evaluator
does have an obligation to check that the automatic testing does not give
misrepresentative results. The implication is thus that this check must be
performed for a sample of the automatic test suite, with the principles for
selecting some tests in preference to others and ensuring a sufficient sample
size applying equally in this case.
1822
The following principles should be followed whenever sampling is
performed:
a)
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it is representative of all of the evidence. The sample size and
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b)
When sampling relates to the correct implementation of the TOE, the
sample should be representative of all aspects relevant to the areas
that are sampled. In particular, the selection should cover a variety of
components, interfaces, developer and operational sites (if more than
one is involved) and hardware platform types (if more than one is
involved). The sample size should be commensurate with the cost
effectiveness of the evaluation and will depend on a number of TOE
dependent factors (e.g. the size and complexity of the TOE, the
amount of documentation).
c)
Also, when sampling relates to specifically gaining evidence that the
developer testing is repeatable and reproducible the sample used must
be sufficient to represent all distinct aspects of developer testing, such
as different test regimes. The sample used must be sufficient to detect
any systematic problem in the developer's functional testing process.
The evaluator contribution resulting from the combination of
repeating developer tests and performing independent tests must be
sufficient to address the major points of concern for the TOE.
d)
Where sampling relates to gaining evidence that a process (e.g.
visitor control or design review) the evaluator should sample
sufficient information to gain reasonable confidence that the
procedure is being followed.
e)
The sponsor and developer should not be informed in advance of the
exact composition of the sample, subject to ensuring timely delivery
of the sample and supporting deliverable, e.g. test harnesses and
equipment to the evaluator in accordance with the evaluation
schedule.
f)
The choice of the sample should be free from bias to the degree
possible (one should not always choose the first or last item). Ideally
the sample selection should be done by someone other than the
evaluator.
1823
Errors found in the sample can be categorised as being either systematic or
sporadic. If the error is systematic, the problem should be corrected and a
complete new sample taken. If properly explained, sporadic errors might be
solved without the need for a new sample, although the explanation should
be confirmed. The evaluator should use judgement in determining whether to
increase the sample size or use a different sample.
A.3
Dependencies
1824
In general it is possible to perform the required evaluation activities, subactivities, and actions in any order or in parallel. However, there are different
kinds of dependencies which have to be considered by the evaluator. This
Section provides general guidance on dependencies between different
activities, sub-activities, and actions.
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A.3.1
Dependencies between activities
1825
For some cases the different assurance classes may recommend or even
require a sequence for the related activities. A specific instance is the ST
activity. The ST evaluation activity is started prior to any TOE evaluation
activities since the ST provides the basis and context to perform them.
However, a final verdict on the ST evaluation may not be possible until the
TOE evaluation is complete, since changes to the ST may result from activity
findings during the TOE evaluation.
A.3.2
Dependencies between sub-activities
1826
Dependencies identified between components in CC Part 3 have to be
considered by the evaluator. Most dependencies are one way, e.g. Evaluation
of sub-activity (AVA_VAN.1) claims a dependency on Evaluation of subactivity (ADV_FSP.1) and Evaluation of sub-activity (AGD_OPE.1). There
are also instances of mutual dependencies, where both components depend
on each other. An example of this is Evaluation of sub-activity
(ATE_FUN.1) and Evaluation of sub-activity (ATE_COV.1).
1827
A sub-activity can be assigned a pass verdict normally only if all those subactivities are successfully completed on which it has a one-way dependency.
For example, a pass verdict on Evaluation of sub-activity (AVA_VAN.1) can
normally only be assigned if the sub-activities related to Evaluation of subactivity (ADV_FSP.1) and Evaluation of sub-activity (AGD_OPE.1) are
assigned a pass verdict too. In the case of mutual dependency the ordering of
these components is down to the evaluator deciding which sub-activity to
perform first. Note this indicates that pass verdicts can normally only be
assigned once both sub-activities have been successful.
1828
So when determining whether a sub-activity will impact another sub-activity,
the evaluator should consider whether this activity depends on potential
evaluation results from any dependent sub-activities. Indeed, it may be the
case that a dependent sub-activity will impact this sub-activity, requiring
previously completed evaluator actions to be performed again.
1829
A significant dependency effect occurs in the case of evaluator-detected
flaws. If a flaw is identified as a result of conducting one sub-activity, the
assignment of a pass verdict to a dependent sub-activity may not be possible
until all flaws related to the sub-activity upon which it depends are resolved.
A.3.3
Dependencies between actions
1830
It may be the case, that results which are generated by the evaluator during
one action are used for performing another action. For example, actions for
completeness and consistency cannot be completed until the checks for
content and presentation have been completed. This means for example that
the evaluator is recommended to evaluate the PP/ST rationale after
evaluating the constituent parts of the PP/ST.
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A.4
Site Visits
A.4.1
Introduction
1831
The assurance class ALC includes requirements for
a)
the application of configuration management, ensuring that the
integrity of the TOE is preserved;
b)
measures, procedures, and standards concerned with secure delivery
of the TOE, ensuring that the security protection offered by the TOE
is not compromised during the transfer to the user,
c)
security measures, used to protect the development environment.
1832
A development site visit is a useful means whereby the evaluator determines
whether procedures are being followed in a manner consistent with that
described in the documentation.
1833
Reasons for visiting sites include:
1834
a)
to observe the use of the CM system as described in the CM plan;
b)
to observe the practical application of delivery procedures as
described in the delivery documentation;
c)
to observe the application of security measures during development
and maintenance of the TOE as described in the development security
documentation.
Specific and detailed information is given in work units for those activities
where site visits are performed:
a)
CM capabilities (ALC_CMC).n with n>=3 (especially work unit
ALC_CMC.3-10 = ALC_CMC.4-13 = ALC_CMC.5-19);
b)
Delivery (ALC_DEL) (especially work unit ALC_DEL.1-2);
c)
Development security (ALC_DVS)
ALC_DVS.1-3 = ALC_DVS.2-4).
(especially
work
unit
A.4.2
General Approach
1835
During an evaluation it is often necessary that the evaluator will meet the
developer more than once and it is a question of good planning to combine
the site visit with another meeting to reduce costs. For example one might
combine the site visits for configuration management, for the developer's
security and for delivery. It may also be necessary to perform more than one
site visit to the same site to allow the checking of all development phases. It
should be considered that development could occur at multiple facilities
within a single building, multiple buildings at the same site, or at multiple
sites.
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1836
The first site visit should be scheduled early during the evaluation. In the
case of an evaluation which starts during the development phase of the TOE,
this will allow corrective actions to be taken, if necessary. In the case of an
evaluation which starts after the development of the TOE, an early site visit
could allow corrective measures to be put in place if serious deficiencies in
the applied procedures emerge. This avoids unnecessary evaluation effort.
1837
Interviews are also a useful means of determining whether the written
procedures reflect what is done. In conducting such interviews, the evaluator
should aim to gain a deeper understanding of the analysed procedures at the
development site, how they are used in practise and whether they are being
applied as described in the provided evaluation evidence. Such interviews
complement but do not replace the examination of evaluation evidence.
1838
As a first step preparing the site visits the evaluators should perform the
evaluator work units concerning the assurance class ALC excluding the
aspects describing the results of the site visit. Based on the information
provided by the relevant developer documentation and the remaining open
questions which were not answered by the documentation the evaluators
compile a check list of the questions which are to be resolved by the site
visits.
1839
The first version of the evaluation report concerning the ALC class and the
check list serves as input for the consultation with the evaluation authority
concerning the site visits.
1840
The check list serve as a guide line for the site visits, which questions are to
be answered by inspection of the relevant measures, their application and
results, and by interviews. Where appropriate, sampling is used for gaining
the required level of confidence (see Section A.2).
1841
The results of the site visits are recorded and serve as input for the final
version of the evaluation report concerning the assurance class ALC.
1842
Other approaches to gain confidence should be considered that provide an
equivalent level of assurance (e.g. to analyse evaluation evidence). Any
decision not to make a visit should be determined in consultation with the
evaluation authority. Appropriate security criteria and a methodology should
be based on other standards of the Information Security Management
Systems area.
A.4.3
Orientation Guide for the Preparation of the Check List
1843
In the following some keywords are provided, which topics should be
checked during an audit.
A.4.3.1
Aspects of configuration management
1844
Basic
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1845
−
Items of the configuration list, including TOE, source code, run time
libraries, design documentation, development tools (ALC_CMC.3-8).
−
Tracking of design documentation, source code, user guidance to
different versions of the TOE.
−
Integration of the configuration system in the design and
development process, test planning, test analysis and quality
management procedures.
Test analysis
−
1846
1847
Tracking of test plans and results to specific configurations and
versions of the TOE.
Access control to development systems
−
Policies for access control and logging.
−
Policies for project specific assignment and changing of access rights.
Clearance
−
Policies for clearance of the TOE and user guidance to the customer.
−
Policies for testing and approving of components and the TOE before
deployment.
A.4.3.2
Aspects of development security
1848
Infrastructure
−
1849
1850
1851
Security measures for physical access control to the development site
and rationale for the effectiveness of these measures.
Organisational measures
−
Organisational structure of the company in respect of the security of
the development environment.
−
Organisational separation between development, production, testing
and quality assurance.
Personal measures
−
Measures for education of the personnel in respect of development
security.
−
Measures and legal agreements of non disclosure of internal
information.
Access control
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1852
1853
1854
−
Assignment of secured objects (for instance TOE, source code, run
time libraries, design documentation, development tools, user
guidance) and security policies.
−
Policies and responsibilities concerning the access control and the
handling of authentication information.
−
Policies for logging of any kind access to the development site and
protection of the logging data.
Input, processing and output of data
−
Security measures for protection of output and output devices
(printer, plotter and displays).
−
Securing of local networks and communication connections.
Storage, transfer and destruction of documents and data media.
−
Policies for handling of documents and data media.
−
Policies and responsibilities for destruction of sorted out documents
and logging of these events.
Data protection
−
1855
Policies and responsibilities for data and information protection (e.g.
for performing backups).
Contingency plan
−
Practises in case of emergency and responsibilities.
−
Documentation of the contingency measures concerning access
control.
−
Information of the personnel about applicable practises in extreme
cases. protection (e.g. for performing backups).
A.4.4
Example of a checklist
1856
The examples of checklists for site visits consist in tables for the preparation
of an audit and for the presentation of the results of an audit.
1857
The checklist structure given in the following is preliminary. Dependent on
the concrete contents of the new guideline, changes might become necessary.
1858
The checklist is divided into three sections according to the subjects
indicated in the introduction (Section A.4.1).
a)
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Configuration management system.
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b)
Delivery procedures.
c)
Security measures during development.
1859
These sections correspond to the actual CC class ALC, especially the
families CM capabilities (ALC_CMC).n with n>=3, Delivery (ALC_DEL)
and Development security (ALC_DVS).
1860
The sections are subdivided further into rows corresponding to the relevant
work units of the CEM.
1861
The columns of the checklist contain in turn
1862
−
a consecutive number,
−
the referenced work unit,
−
the references to the corresponding developer documentation,
−
the explicit reproduction of the developer measures,
−
special remarks and questions to be clarified on the visit (beyond the
standard evaluator task to verify the application of the indicated
measures),
−
the result of the examinations during the visit.
If it is decided to have separate checklists for preparation and reporting of the
audit, the result column is omitted in the preparation list and the remarks and
questions column is omitted in the reporting list. The remaining columns
should be identical in both lists.
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Table 1 Example of a checklist at EAL 4 (extract)
A. Examination of the CM system (ALC_CMC.4 and ALC_CMS.4)
Developer
No
Questions
Documentati Measures
Work Unit
Result
.
and Remarks
on
The system
automaticall
If a user
y managing
has not
the source
the right
code files is
Does reading to access
capable of
or updating
a
“Configurati administerin
ALC_CMC.
of a source
confidenti
on
g user
A. 4-11,
code file
al
Management profiles and
1
ALC_CMC.
require a
document,
System”, ch. graded
4-12
user
it is not
...
access
authenticatio even
rights, and
n?
displayed
of checking
to him in
identificatio
the file
n and
list.
authenticati
on of users.
... ...
...
...
...
...
B. Examination of the Delivery Procedures (ALC_DEL.1)
Questions
Developer
No. Work Unit
Measures
and
Result
Documentation
Remarks
The
evaluators
The
have
software is
checked the
ALC_DEL.1transmitted
“Delivery of
process and
1,
PGPB.1
the TOE”, ch.
--found it as
ALC_DEL.1signed and
...
described,
2
encrypted
additionally
to the
a checksum
customer.
is
transmitted.
...
...
...
...
...
...
C. Examination of the organisational and infrastructural developer security
(ALC_DVS.1, ALC_LCD.1, ALC_TAT.1)
Developer
Questions
No
Work Unit
Documentatio Measures
and
Result
.
n
Remarks
ALC_DVS.1 “Security of
The
Is the
The
C.
-1,
the
premises
fencing
evaluators
1
ALC_DVS.1 development
are
sufficientl considered
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C. Examination of the organisational and infrastructural developer security
(ALC_DVS.1, ALC_LCD.1, ALC_TAT.1)
Developer
Questions
No
Work Unit
Documentatio Measures
and
Result
.
n
Remarks
-2
environment”, protected
y strong
the fencing
ch. ...
by security and high to to be
(Premises)
fencing.
prevent an sufficiently
easy
strong and
intrusion
high.
into the
premises?
The
building
has the
following
Beyond the
access
indicated
possibilitie
access
s: The main
possibilitie
entrance
s, there is
which is
an
surveyed
emergency
by the
“Security of
Is the
exit that
reception
ALC_DVS.1 the
listing of
cannot be
and is
C. -1,
development
the access
opened
2
ALC_DVS.1 environment”, closed if
possibilitie
from the
the
-2
ch. ...
s
outside.
reception is complete?
(Building)
The roller
not
shutters
manned.
mentioned
And an
before can
access in
be operated
the goods
only from
reception
inside.
which is
secured by
two roller
shutters.
...
...
...
...
...
...
A.5
Scheme Responsibilities
1863
This CEM describes the minimum technical work that evaluations conducted
under oversight (scheme) bodies must perform. However, it also recognises
(both explicitly and implicitly) that there are activities or methods upon
which mutual recognition of evaluation results do not rely. For the purposes
of thoroughness and clarity, and to better delineate where the CEM ends and
an individual scheme's methodology begins, the following matters are left up
to the discretion of the schemes. Schemes may choose to provide the
following, although they may choose to leave some unspecified. (Every
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effort has been made to ensure this list is complete; evaluators encountering
a subject neither listed here nor addressed in the CEM should consult with
their evaluation schemes to determine under whose auspices the subject
falls.)
1864
The matters that schemes may choose to specify include:
a)
what is required in ensuring that an evaluation was done sufficiently every scheme has a means of verifying the technical competence,
understanding of work and the work of its evaluators, whether by
requiring the evaluators to present their findings to the oversight
body, by requiring the oversight body to redo the evaluator's work, or
by some other means that assures the scheme that all evaluation
bodies are adequate and comparable;
b)
process for disposing of evaluation evidence upon completion of an
evaluation;
c)
any requirements for confidentiality (on the part of the evaluator and
the non-disclosure of information obtained during evaluation);
d)
the course of action to be taken if a problem is encountered during the
evaluation (whether the evaluation continues once the problem is
remedied, or the evaluation ends immediately and the remedied
product must be re-submitted for evaluation);
e)
any specific (natural) language in which documentation must be
provided;
f)
any recorded evidence that must be submitted in the ETR - this CEM
specifies the minimum to be reported in an ETR; however, individual
schemes may require additional information to be included;
g)
any additional reports (other than the ETR) required from the
evaluators -for example, testing reports;
h)
any specific ORs that may be required by the scheme, including the
structure, recipients, etc. of any such ORs;
i)
any specific content structure of any written report as a result from an
ST evaluation - a scheme may have a specific format for all of its
reports detailing results of an evaluation, be it the evaluation of a
TOE or of an ST;
j)
any additional PP/ST identification information required;
k)
any activities to determine the suitability of explicitly-stated
requirements in an ST;
l)
any requirements for provision of evaluator evidence to support reevaluation and re-use of evidence;
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m)
any specific handling of scheme identifiers, logos, trademarks, etc.;
n)
any specific guidance in dealing with cryptography;
o)
handling and application of scheme, national and international
interpretations;
p)
a list or characterisations of suitable alternative approaches to testing
where testing is infeasible;
q)
the mechanism by which an overseer can determine what steps an
evaluator took while testing;
r)
preferred test approach (if any): at internal interface or at external
interface;
s)
a list or characterisation of acceptable means of conducting the
evaluator's vulnerability analysis (e.g. flaw hypothesis methodology);
t)
information regarding any vulnerabilities and weaknesses to be
considered.
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B
Vulnerability Assessment (AVA)
(normative)
1865
This annex provides an explanation of the AVA_VAN criteria and examples
of their application. This annex does not define the AVA criteria; this
definition can be found in CC Part 3 Section Class AVA: Vulnerability
assessment.
1866
This annex consists of 2 major parts:
a)
Guidance for completing an independent vulnerability analysis. This
is summarised in section B.1, and described in more detail in section
B.2 . These sections describe how an evaluator should approach the
construction of an independent Vulnerability Analysis.
b)
How to characterise and use assumed Attack Potential of an attacker.
This is described in sections B.3 to B.5. These sections provide an
example of describe how an attack potential can be characterised and
should be used, and provide examples.
B.1
What is Vulnerability Analysis
1867
The purpose of the vulnerability assessment activity is to determine the
existence and exploitability of flaws or weaknesses in the TOE in the
operational environment. This determination is based upon analysis
performed by the evaluator, and is supported by evaluator testing.
1868
At the lowest levels of Vulnerability analysis (AVA_VAN) the evaluator
simply performs a search of publicly available information to identify any
known weaknesses in the TOE, while at the higher levels the evaluator
performs a structured analysis of the TOE evaluation evidence.
1869
There are two main factors in performing a vulnerability analysis, namely;
a)
the identification of potential vulnerabilities;
b)
penetration testing to determine whether the potential vulnerabilities
are exploitable in the operational environment of the TOE.
1870
The identification of vulnerabilities can be further decomposed into the
evidence to be searched and how hard to search that evidence to identify
potential vulnerabilities. In a similar manner, the penetration testing can be
further decomposed into analysis of the potential vulnerability to identify
attack methods and the demonstration of the attack methods.
1871
These main factors are iterative in nature, i.e. penetration testing of potential
vulnerabilities may lead to the identification of further potential
vulnerabilities. Hence, these are performed as a single vulnerability analysis
activity.
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B.2
Evaluator construction of a Vulnerability Analysis
1872
The evaluator vulnerability analysis is to determine that the TOE is resistant
to penetration attacks performed by an attacker possessing a Basic (for
AVA_VAN.1 and AVA_VAN.2), Enhanced-Basic (for AVA_VAN.3),
Moderate (for AVA_VAN.4) or High (for AVA_VAN.5) attack potential.
The evaluator first assesses the exploitability of all identified potential
vulnerabilities. This is accomplished by conducting penetration testing. The
evaluator should assume the role of an attacker with a Basic (for
AVA_VAN.1 and AVA_VAN.2), Enhanced-Basic (for AVA_VAN.3),
Moderate (for AVA_VAN.4) or High (for AVA_VAN.5) attack potential
when attempting to penetrate the TOE.
1873
The evaluator considers potential vulnerabilities encountered by the
evaluator during the conduct of other evaluation activities. The evaluator
penetration testing determining TOE resistance to these potential
vulnerabilities should be performed assuming the role of an attacker with a
Basic (for AVA_VAN.1 and AVA_VAN.2), Enhanced-Basic (for
AVA_VAN.3), Moderate (for AVA_VAN.4) or High (for AVA_VAN.5)
attack potential.
1874
However, vulnerability analysis should not be performed as an isolated
activity. It is closely linked with ADV and AGD. The evaluator performs
these other evaluation activities with a focus on identifying potential
vulnerabilities or “areas of concern”. Therefore, evaluator familiarity with
the generic vulnerability guidance (provided in Section B.2.1) is required.
B.2.1
Generic vulnerability guidance
1875
The following five categories provide discussion of generic vulnerabilities.
B.2.1.1
Bypassing
1876
Bypassing includes any means by which an attacker could avoid security
enforcement, by:
1877
a)
exploiting the capabilities of interfaces to the TOE, or of utilities
which can interact with the TOE;
b)
inheriting privileges or other capabilities that should otherwise be
denied;
c)
(where confidentiality is a concern) reading sensitive data stored or
copied to inadequately protected areas.
Each of the following should be considered (where relevant) in the
evaluator's independent vulnerability analysis.
a)
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Attacks based on exploiting the capabilities of interfaces or utilities
generally take advantage of the absence of the required security
enforcement on those interfaces. For example, gaining access to
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functionality that is implemented at a lower level than that at which
access control is enforced. Relevant items include:
1)
changing the predefined sequence of invocation of TSFI;
2)
invoking an additional TSFI;
3)
using a component in an unexpected context or for an
unexpected purpose;
4)
using implementation detail introduced in less abstract
representations;
5)
using the delay between time of access check and time of use.
b)
Changing the predefined sequence of invocation of components
should be considered where there is an expected order in which
interfaces to the TOE (e.g. user commands) are called to invoke a
TSFI (e.g. opening a file for access and then reading data from it). If
a TSFI is invoked through one of the TOE interfaces (e.g. an access
control check), the evaluator should consider whether it is possible to
bypass the control by performing the call at a later point in the
sequence or by missing it out altogether.
c)
Executing an additional component (in the predefined sequence) is a
similar form of attack to the one described above, but involves the
calling of some other TOE interface at some point in the sequence. It
can also involve attacks based on interception of sensitive data passed
over a network by use of network traffic analysers (the additional
component here being the network traffic analyser).
d)
Using a component in an unexpected context or for an unexpected
purpose includes using an unrelated TOE interface to bypass the TSF
by using it to achieve a purpose that it was not designed or intended
to achieve. Covert channels are an example of this type of attack (see
B.2.1.4 for further discussion of covert channels). The use of
undocumented interfaces, which may be insecure, also falls into this
category. Such interfaces may include undocumented support and
help facilities.
e)
Using implementation detail introduced in lower representations may
allow an attacker to take advantage of additional functions, resources
or attributes that are introduced to the TOE as a consequence of the
refinement process. Additional functionality may include test harness
code contained in software modules and back-doors introduced
during the implementation process.
f)
Using the delay between time of check and time of use includes
scenarios where an access control check is made and access granted,
and an attacker is subsequently able to create conditions in which,
had they applied at the time the access check was made, would have
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caused the check to fail. An example would be a user creating a
background process to read and send highly sensitive data to the
user's terminal, and then logging out and logging back in again at a
lower sensitivity level. If the background process is not terminated
when the user logs off, the MAC checks would have been effectively
bypassed.
g)
Attacks based on inheriting privileges are generally based on illicitly
acquiring the privileges or capabilities of some privileged component,
usually by exiting from it in an uncontrolled or unexpected manner.
Relevant items include:
1)
executing data not intended to be executable, or making it
executable;
2)
generating unexpected input for a component;
3)
invalidating assumptions and properties on which lower-level
components rely.
h)
Executing data not intended to be executable, or making it executable
includes attacks involving viruses (e.g. putting executable code or
commands in a file which are automatically executed when the file is
edited or accessed, thus inheriting any privileges the owner of the file
has).
i)
Generating unexpected input for a component can have unexpected
effects which an attacker could take advantage of. For example, if the
TSF could be bypassed if a user gains access to the underlying
operating system, it may be possible to gain such access following
the login sequence by exploring the effect of hitting various control
or escape sequences whilst a password is being authenticated.
j)
Invalidating assumptions and properties on which lower level
components rely includes attacks based on breaking out of the
constraints of an application to gain access to an underlying operating
system in order to bypass the TSF of an application. In this case the
assumption being invalidated is that it is not possible for a user of the
application to gain such access. A similar attack can be envisaged
against an application on an underlying database management
system: again the TSF could be bypassed if an attacker can break out
of the constraints of the application.
k)
Attacks based on reading sensitive data stored in inadequately
protected areas (applicable where confidentiality is a concern)
include the following issues which should be considered as possible
means of gaining access to sensitive data:
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1)
disk scavenging;
2)
access to unprotected memory;
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3)
exploiting access to shared writable files or other shared
resources (e.g. swap files);
4)
Activating error recovery to determine what access users can
obtain. For example, after a crash an automatic file recovery
system may employ a lost and found directory for headerless
files, which are on disk without labels. If the TOE implements
mandatory access controls, it is important to investigate at
what security level this directory is kept (e.g. at system high),
and who has access to this directory.
1878
There are a number of different methods through which an evaluator may
identify a back-door, including two main techniques. Firstly, by the evaluator
inadvertently identifying during testing an interface that can be misused.
Secondly, through testing each external interface of the TSF in a debugging
mode to identify any modules that are not called as a part of testing the
documented interfaces and then inspecting the code that is not called to
consider whether it is a back-door.
1879
For a software TOE where Evaluation of sub-activity (ADV_IMP.2) and
ALC_TAT.2 or higher components are included in the assurance package,
the evaluator may consider during their analysis of the tools the libraries and
packages that are linked by the compiler at compilation stage to determine
that back-doors are not introduced at this stage.
B.2.1.2
Tampering
1880
Tampering includes any attack based on an attacker attempting to influence
the behaviour of the TSF (i.e. corruption or de-activation), for example by:
1881
a)
accessing data on whose confidentiality or integrity the TSF relies;
b)
forcing the TOE to cope with unusual or unexpected circumstances;
c)
disabling or delaying security enforcement;
d)
physical modification the TOE.
Each of the following should be considered (where relevant) in the
evaluator's independent vulnerability analysis.
a)
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Attacks based on accessing data, whose confidentiality or integrity
are protected, include:
1)
reading, writing or modifying internal data directly or
indirectly;
2)
using a component in an unexpected context or for an
unexpected purpose;
3)
using interfaces between components that are not visible at a
higher level of abstraction.
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b)
Reading, writing or modifying internal data directly or indirectly
includes the following types of attack which should be considered:
1)
reading “secrets” stored internally, such as user passwords;
2)
spoofing internal data that security enforcing mechanisms rely
upon;
3)
modifying environment variables (e.g. logical names), or data
in configuration files or temporary files.
c)
It may be possible to deceive a trusted process into modifying a
protected file that it wouldn't normally access.
d)
The evaluator should also consider the following “dangerous
features”:
1)
source code resident on the TOE along with a compiler (for
instance, it may be possible to modify the login source code);
2)
an interactive debugger and patch facility (for instance, it may
be possible to modify the executable image);
3)
the possibility of making changes at device controller level,
where file protection does not exist;
4)
diagnostic code which exists in the source code and that may
be optionally included;
5)
developer's tools left in the TOE.
e)
Using a component in an unexpected context or for an unexpected
purpose includes (for example), where the TOE is an application built
upon an operating system, users exploiting knowledge of a word
processor package or other editor to modify their own command file
(e.g. to acquire greater privileges).
f)
Using interfaces between components which are not visible at a
higher level of abstraction includes attacks exploiting shared access
to resources, where modification of a resource by one component can
influence the behaviour of another (trusted) component, e.g. at source
code level, through the use of global data or indirect mechanisms
such as shared memory or semaphores.
g)
Attacks based on forcing the TOE to cope with unusual or
unexpected circumstances should always be considered. Relevant
items include:
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1)
generating unexpected input for a component;
2)
invalidating assumptions and properties on which lower-level
components rely.
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h)
Generating unexpected input for a component includes investigating
the behaviour of the TOE when:
1)
command input buffers overflow (possibly “crashing the
stack” or overwriting other storage, which an attacker may be
able to take advantage of, or forcing a crash dump that may
contain sensitive information such as clear-text passwords);
2)
invalid commands or parameters are entered (including
supplying a read-only parameter to an interface which expects
to return data via that parameter and supplying improperly
formatted input that should fail parsing such as SQLinjection, format strings);
3)
an end-of-file marker (e.g. CTRL-Z or CTRL-D) or null
character is inserted in an audit trail.
i)
Invalidating assumptions and properties on which lower-level
components rely includes attacks taking advantage of errors in the
source code where the code assumes (explicitly or implicitly) that
security relevant data is in a particular format or has a particular
range of values. In these cases the evaluator should determine
whether they can invalidate such assumptions by causing the data to
be in a different format or to have different values, and if so whether
this could confer advantage to an attacker.
j)
The correct behaviour of the TSF may be dependent on assumptions
that are invalidated under extreme circumstances where resource
limits are reached or parameters reach their maximum value. The
evaluator should consider (where practical) the behaviour of the TOE
when these limits are reached, for example:
k)
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1)
changing dates (e.g. examining how the TOE behaves when a
critical date threshold is passed);
2)
filling disks;
3)
exceeding the maximum number of users;
4)
filling the audit log;
5)
saturating security alarm queues at a console;
6)
overloading various parts of a multi-user TOE which relies
heavily upon communications components;
7)
swamping a network, or individual hosts, with traffic;
8)
filling buffers or fields.
Attacks based on disabling or delaying security enforcement include
the following items:
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l)
1)
using interrupts or scheduling functions to disrupt sequencing;
2)
disrupting concurrence;
3)
using interfaces between components which are not visible at
a higher level of abstraction.
Using interrupts or scheduling functions to disrupt sequencing
includes investigating the behaviour of the TOE when:
1)
a command is interrupted (with CTRL-C, CTRL-Y, etc.);
2)
a second interrupt is issued before the first is acknowledged.
m)
The effects of terminating security critical processes (e.g. an audit
daemon) should be explored. Similarly, it may be possible to delay
the logging of audit records or the issuing or receipt of alarms such
that it is of no use to an administrator (since the attack may already
have succeeded).
n)
Disrupting concurrence includes investigating the behaviour of the
TOE when two or more subjects attempt simultaneous access. It may
be that the TOE can cope with the interlocking required when two
subjects attempt simultaneous access, but that the behaviour becomes
less well defined in the presence of further subjects. For example, a
critical security process could be put into a resource-wait state if two
other processes are accessing a resource which it requires.
o)
Using interfaces between components which are not visible at a
higher level of abstraction may provide a means of delaying a timecritical trusted process.
p)
Physical attacks can be categorised into physical probing, physical
manipulation, physical modification, and substitution.
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1)
Physical probing by penetrating the TOE targeting internals of
the TOE, e.g. reading at internal communication interfaces,
lines or memories.
2)
Physical manipulation can be with the TOE internals aiming
at internal modifications of the TOE (e.g. by using optical
fault induction as an interaction process), at the external
interfaces of the TOE (e.g. by power or clock glitches) and at
the TOE environment (e.g. by modifying temperature).
3)
Physical modification of TOE internal security enforcing
attributes to inherit privileges or other capabilities that should
be denied in regular operation. Such modifications can be
caused, e.g., by optical fault induction. Attacks based on
physical modification may also yield a modification of the
TSF itself, e.g. by causing faults at TOE internal program data
transfers before execution. Note, that such kind of bypassing
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by modifying the TSF itself can jeopardise every TSF unless
there are other measures (possibly environmental measures)
that prevent an attacker from gaining physical access to the
TOE.
4)
Physical substitution to replace the TOE with another IT
entity, during delivery or operation of the TOE. Substitution
during delivery of the TOE from the development
environment to the user should be prevented through
application of secure delivery procedures (such as those
considered under Development security (ALC_DVS)).
Substitution of the TOE during operation may be considered
through a combination of user guidance and the operational
environment, such that the user is able to be confident that
they are interacting with the TOE.
B.2.1.3
Direct attacks
1882
Direct attack includes the identification of any penetration tests necessary to
test the strength of permutational or probabilistic mechanism and other
mechanisms to ensure they withstand direct attack.
1883
For example, it may be a flawed assumption that a particular implementation
of a pseudo-random number generator will possess the required entropy
necessary to seed the security mechanism.
1884
Where a probabilistic or permutational mechanism relies on selection of
security attribute value (e.g. selection of password length) or entry of data by
a human user (e.g. choice of password), the assumptions made should reflect
the worst case.
1885
Probabilistic or permutational mechanisms should be identified during
examination of evaluation evidence required as input to this sub-activity
(security target, functional specification, TOE design and implementation
representation subset) and any other TOE (e.g. guidance) documentation may
identify additional probabilistic or permutational mechanisms.
1886
Where the design evidence or guidance includes assertions or assumptions
(e.g. about how many authentication attempts are possible per minute), the
evaluator should independently confirm that these are correct. This may be
achieved through testing or through independent analysis.
1887
Direct attacks reliant upon a weakness in a cryptographic algorithm should
not be considered under Vulnerability analysis (AVA_VAN), as this is
outside the scope of the CC. Correctness of the implementation of the
cryptographic algorithm is considered during the ADV and ATE activities.
B.2.1.4
Monitoring
1888
Information is an abstract view on relation between the properties of entities,
i.e. a signal contains information for a system, if the TOE is able to react to
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this signal. The TOE resources processes and stores information represented
by user data. Therefore:
a)
information may flow with the user data between subjects by internal
TOE transfer or export from the TOE;
b)
information may be generated and passed to other user data;
c)
information may be gained through monitoring the operations on data
representing the information.
1889
The information represented by user data may be characterised by security
attributes like “classification level” having values, for example unclassified,
confidential, secret, top secret, to control operations to the data. This
information and therefore the security attributes may be changed by
operations e.g. FDP_ACC.2 may describe decrease of the level by
“sanitarisation” or increase of level by combination of data. This is one
aspects of an information flow analysis focused on controlled operations of
controlled subjects on controlled objects.
1890
The other aspect is the analysis of illicit information flow. This aspect is
more general than the direct access to objects containing user data addressed
by the FDP_ACC family. An unenforced signalling channel carrying
information under control of the information flow control policy can also be
caused by monitoring of the processing of any object containing or related to
this information (e.g. side channels). An enforced signalling channels may
be identified in terms of the subjects manipulating resources and the subject
or user that observe such manipulation. Classically, covert channels have
been identified as timing or storage channels, according to the resource being
modified or modulated. As for other monitoring attacks, the use of the TOE
is in accordance with the SFRs.
1891
Covert channels are normally applicable in the case when the TOE has
unobservability AND multi-level separation policy requirements. Covert
channels may be routinely spotted during vulnerability analysis and design
activities, and should therefore be tested. However, generally such
monitoring attacks are only identified through specialised analysis
techniques commonly referred to as “covert channel analysis”. These
techniques have been the subject of much research and there are many papers
published on this subject. Guidance for the conduct of covert channel
analysis should be sought from the evaluation authority.
1892
Unenforced information flow monitoring attacks include passive analysis
techniques aiming at disclosure of sensitive internal data of the TOE by
operating the TOE in the way that corresponds to the guidance documents.
1893
Side Channel Analysis includes crypt analytical techniques based on physical
leakage of the TOE. Physical leakage can occur by timing information,
power consumption or power emanation during computation of a TSF.
Timing information can be collected also by a remote-attacker (having
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network access to the TOE), power based information channels requires that
the attacker is in the near-by environment of the TOE.
1894
Eavesdropping techniques include interception of all forms of energy, e.g.,
electromagnetic or optical emanation of computer displays, not necessarily in
the near-field of the TOE.
1895
Monitoring also includes exploits of protocol flaws, e.g., an attack on SSL
implementation.
B.2.1.5
Misuse
1896
Misuse may arise from:
a)
incomplete guidance documentation;
b)
unreasonable guidance;
c)
unintended misconfiguration of the TOE;
d)
forced exception behaviour of the TOE.
1897
If the guidance documentation is incomplete the user may not know how to
operate the TOE in accordance with the SFRs. The evaluator should apply
familiarity with the TOE gained from performing other evaluation activities
to determine that the guidance is complete. In particular, the evaluator should
consider the functional specification. The TSF described in this document
should be described in the guidance as required to permit secure
administration and use through the TSFI available to human users. In
addition, the different modes of operation should be considered to ensure that
guidance is provided for all modes of operation.
1898
The evaluator may, as an aid, prepare an informal mapping between the
guidance and these documents. Any omissions in this mapping may indicate
incompleteness.
1899
The guidance is considered to be unreasonable if it makes demands on the
TOE's usage or operational environment that are inconsistent with the ST or
unduly onerous to maintain security.
1900
A TOE may use a variety of ways to assist the consumer in effectively using
that TOE in accordance with the SFRs and prevent unintentional
misconfiguration. A TOE may employ functionality (features) to alert the
consumer when the TOE is in a state that is inconsistent with the SFRs,
whilst other TOEs may be delivered with enhanced guidance containing
suggestions, hints, procedures, etc. on using the existing security features
most effectively; for instance, guidance on using the audit feature as an aid
for detecting when the SFRs are being compromised; namely insecure.
1901
The evaluator considers the TOE's functionality, its purpose and security
objectives for the operational environment to arrive at a conclusion of
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whether or not there is reasonable expectation that use of the guidance would
permit transition into an insecure state to be detected in a timely manner.
1902
The potential for the TOE to enter into insecure states may be determined
using the evaluation deliverables, such as the ST, the functional specification
and any other design representations provided as evidence for components
included in the assurance package for the TOE (e.g. the TOE/TSF design
specification if a component from TOE design (ADV_TDS) is included).
1903
Instances of forced exception behaviour of the TSF could include, but are not
limited to, the following:
a)
behaviour of the TOE when start-up, close-down or error recovery is
activated;
b)
behaviour of the TOE under extreme circumstances (sometimes
termed overload or asymptotic behaviour), particularly where this
could lead to the de-activation or disabling of parts of the TSF;
c)
any potential for unintentional misconfiguration or insecure use
arising from attacks noted in the section on tampering above.
B.2.2
Identification of Potential Vulnerabilities
1904
Potential vulnerabilities may be identified by the evaluator during different
activities. They may become apparent during an evaluation activity or they
may be identified as a result of analysis of evidence to search for
vulnerabilities.
B.2.2.1
Encountered
1905
The encountered identification of vulnerabilities is where potential
vulnerabilities are identified by the evaluator during the conduct of
evaluation activities, i.e. the evidence are not being analysed with the express
aim of identifying potential vulnerabilities.
1906
The encountered method of identification is dependent on the evaluator's
experience and knowledge; which is monitored and controlled by the
Certification Authority. It is not reproducible in approach, but will be
documented to ensure repeatability of the conclusions from the reported
potential vulnerabilities.
1907
There are no formal analysis criteria required for this method. Potential
vulnerabilities are identified from the evidence provided as a result of
knowledge and experience. However, this method of identification is not
constrained to any particular subset of evidence.
1908
Evaluator is assumed to have knowledge of the TOE-type technology and
known security flaws as documented in the public domain. The level of
knowledge assumed is that which can be gained from a security e-mail list
relevant to the TOE type, the regular bulletins (bug, vulnerability and
security flaw lists) published by those organisations researching security
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issues in products and technologies in widespread use. This knowledge is not
expected to extend to specific conference proceedings or detailed theses
produced by university research for AVA_VAN.1 or AVA_VAN.2.
However, to ensure the knowledge applied is up to date, the evaluator may
need to perform a search of public domain material.
1909
For AVA_VAN.3 to AVA_VAN.5 the search of publicly available
information is expected to include conference proceeding and theses
produced during research activities by universities and other relevant
organisations.
1910
Examples of how these may arise (how the evaluator may encounter
potential vulnerabilities):
a)
while the evaluator is examining some evidence, it sparks a memory
of a potential vulnerability identified in a similar product type, that
the evaluator believes to also be present in the TOE under evaluation;
b)
while examining some evidence, the evaluator spots a flaw in the
specification of an interface, that reflects a potential vulnerability.
1911
This may include becoming aware of a potential vulnerability in a TOE
through reading about generic vulnerabilities in a particular product type in
an IT security publication or on a security e-mail list to which the evaluator
is subscribed.
1912
Attack methods can be developed directly from these potential
vulnerabilities. Therefore, the encountered potential vulnerabilities are
collated at the time of producing penetration tests based on the evaluator's
vulnerability analysis. There is no explicit action for the evaluator to
encounter potential vulnerabilities. Therefore, the evaluator is directed
through an implicit action specified in AVA_VAN.1.2E and
AVA_VAN.*.4E.
1913
Current information regarding public domain vulnerabilities and attacks may
be provided to the evaluator by, for example, an evaluation authority. This
information is to be taken into account by the evaluator when collating
encountered vulnerabilities and attack methods when developing penetration
tests.
B.2.2.2
Analysis
1914
The following types of analysis are presented in terms of the evaluator
actions.
B.2.2.2.1
Unstructured Analysis
1915
The unstructured analysis to be performed by the evaluator (for Evaluation of
sub-activity (AVA_VAN.2)) permits the evaluator to consider the generic
vulnerabilities (as discussed in B.2.1). The evaluator will also apply their
experience and knowledge of flaws in similar technology types.
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B.2.2.2.2
Focused
1916
During the conduct of evaluation activities the evaluator may also identify
areas of concern. These are specific portions of the TOE evidence that the
evaluator has some reservation about, although the evidence meets the
requirements for the activity with which the evidence is associated. For
example, a particular interface specification looks particularly complex, and
therefore may be prone to error either in the development of the TOE or in
the operation of the TOE. There is no potential vulnerability apparent at this
stage, further investigation is required. This is beyond the bounds of
encountered, as further investigation is required.
1917
Difference between potential vulnerability and area of concern:
a)
Potential vulnerability - The evaluator knows a method of attack that
can be used to exploit the weakness or the evaluator knows of
vulnerability information that is relevant to the TOE.
b)
Area of concern - The evaluator may be able to discount concern as a
potential vulnerability based on information provided elsewhere.
While reading interface specification, the evaluator identifies that due
to the extreme (unnecessary) complexity of an interface a potential
vulnerability may lay within that area, although it is not apparent
through this initial examination.
1918
The focused approach to the identification of vulnerabilities is an analysis of
the evidence with the aim of identifying any potential vulnerabilities evident
through the contained information. It is an unstructured analysis, as the
approach is not predetermined. This approach to the identification of
potential vulnerabilities can be used during the independent vulnerability
analysis required by Evaluation of sub-activity (AVA_VAN.3).
1919
This analysis can be achieved through different approaches, that will lead to
commensurate levels of confidence. None of the approaches have a rigid
format for the examination of evidence to be performed.
1920
The approach taken is directed by the results of the evaluator's assessment of
the evidence to determine it meets the requirements of the AVA/AGD subactivities. Therefore, the investigation of the evidence for the existence of
potential vulnerabilities may be directed by any of the following:
a)
areas of concern identified during examination of the evidence during
the conduct of evaluation activities;
b)
reliance on particular functionality to provide separation, identified
during the analysis of the architectural design (as in Evaluation of
sub-activity (ADV_ARC.1)), requiring further analysis to determine
it cannot be bypassed;
c)
representative examination of the evidence to hypothesise potential
vulnerabilities in the TOE.
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1921
The evaluator will report what actions were taken to identify potential
vulnerabilities in the evidence. However, the evaluator may not be able to
describe the steps in identifying potential vulnerabilities before the outset of
the examination. The approach will evolve as a result of the outcome of
evaluation activities.
1922
The areas of concern may arise from examination of any of the evidence
provided to satisfy the SARs specified for the TOE evaluation. The
information publicly accessible is also considered.
1923
The activities performed by the evaluator can be repeated and the same
conclusions, in terms of the level of assurance in the TOE, can be reached
although the steps taken to achieve those conclusions may vary. As the
evaluator is documenting the form the analysis took, the actual steps taken to
achieve those conclusions are also reproducible.
B.2.2.2.3
Methodical
1924
The methodical analysis approach takes the form of a structured examination
of the evidence. This method requires the evaluator to specify the structure
and form the analysis will take (i.e. the manner in which the analysis is
performed is predetermined, unlike the focused identification method). The
method is specified in terms of the information that will be considered and
how/why it will be considered. This approach to the identification of
potential vulnerabilities can be used during the independent vulnerability
analysis required by Evaluation of sub-activity (AVA_VAN.4) and
Evaluation of sub-activity (AVA_VAN.5).
1925
This analysis of the evidence is deliberate and pre-planned in approach,
considering all evidence identified as an input into the analysis.
1926
All evidence provided to satisfy the (ADV) assurance requirements specified
in the assurance package are used as input to the potential vulnerability
identification activity.
1927
The “methodical” descriptor for this analysis has been used in an attempt to
capture the characterisation that this identification of potential vulnerabilities
is to take an ordered and planned approach. A “method” or “system” is to be
applied in the examination. The evaluator is to describe the method to be
used in terms of what evidence will be considered, the information within the
evidence that is to be examined, the manner in which this information is to
be considered; and the hypothesis that is to be generated.
1928
The following provide some examples that a hypothesis may take:
a)
consideration of malformed input for interfaces available to an
attacker at the external interfaces;
b)
examination of a security mechanism, such as domain separation,
hypothesising internal buffer overflows leading to degradation of
separation;
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c)
analysis to identify any objects created in the TOE implementation
representation that are then not fully controlled by the TSF, and could
be used by an attacker to undermine the SFRs.
1929
For example, the evaluator may identify that interfaces are a potential area of
weakness in the TOE and specify an approach to the analysis that “all
interface specifications provided in the functional specification and TOE
design will be analysed to hypothesise potential vulnerabilities” and go on to
explain the methods used in the hypothesis.
1930
This identification method will provide a plan of attack of the TOE, that
would be performed by an evaluator completing penetration testing of
potential vulnerabilities in the TOE. The rationale for the method of
identification would provide the evidence for the coverage and depth of
exploitation determination that would be performed on the TOE.
B.3
When attack potential is used
B.3.1
Developer
1931
Attack potential is used by a PP/ST author during the development of the
PP/ST, in consideration of the threat environment and the selection of
assurance components. This may simply be a determination that the attack
potential possessed by the assumed attackers of the TOE is generically
characterised as Basic, Enhanced-Basic, Moderate or High. Alternatively, the
PP/ST may wish to specify particular levels of individual factors assumed to
be possessed by attackers. (e.g. the attackers are assumed to be experts in the
TOE technology type, with access to specialised equipment.)
1932
The PP/ST author considers the threat profile developed during a risk
assessment (outside the scope of the CC, but used as an input into the
development of the PP/ST in terms of the Security Problem Definition or in
the case of low assurance STs, the objectives statement). Consideration of
this threat profile in terms of one of the approaches discussed in the
following sections will permit the specification of the attack potential the
TOE is to resist.
B.3.2
Evaluator
1933
Attack potential is especially considered by the evaluator in two distinct
ways during the ST evaluation and the vulnerability assessment activities.
1934
Attack potential is used by an evaluator during the conduct of the
vulnerability analysis sub-activity to determine whether or not the TOE is
resistant to attacks assuming a specific attack potential of an attacker. If the
evaluator determines that a potential vulnerability is exploitable in the TOE,
they have to confirm that it is exploitable considering all aspects of the
intended environment, including the attack potential assumed by an attacker.
1935
Therefore, using the information provided in the threat statement of the
Security Target, the evaluator determines the minimum attack potential
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required by an attacker to effect an attack, and arrives at some conclusion
about the TOE's resistance to attacks. Table 2 demonstrates the relationship
between this analysis and attack potential.
Vulnerability
Component
VAN.5
VAN.4
VAN.3
VAN.2
VAN.1
TOE resistant to
attacker with attack
potential of:
High
Moderate
Enhanced-Basic
Basic
Basic
Residual vulnerabilities only
exploitable by attacker with
attack potential of:
Beyond High
High
Moderate
Enhanced-Basic
Enhanced-Basic
Table 2 Vulnerability testing and attack potential
1936
The “beyond high” entry in the residual vulnerabilities column of the above
table represents those potential vulnerabilities that would require an attacker
to have an attack potential greater than that of “high” in order to exploit the
potential vulnerability. A vulnerability classified as residual in this instance
reflects the fact that a known weakness exists in the TOE, but in the current
operational environment, with the assumed attack potential, the weakness
cannot be exploited.
1937
At any level of attack potential a potential vulnerability may be deemed
“infeasible” due to a countermeasure in the operational environment that
prevents the vulnerability from being exploited.
1938
A vulnerability analysis applies to all TSFI, including ones that access
probabilistic or permutational mechanisms. No assumptions are made
regarding the correctness of the design and implementation of the TSFI; nor
are constraints placed on the attack method or the attacker's interaction with
the TOE - if an attack is possible, then it is to be considered during the
vulnerability analysis. As shown in Table 2, successful evaluation against a
vulnerability assurance component reflects that the TSF is designed and
implemented to protect against the required level of threat.
1939
It is not necessary for an evaluator to perform an attack potential calculation
for each potential vulnerability. In some cases it is apparent when developing
the attack method whether or not the attack potential required to develop and
run the attack method is commensurate with that assumed of the attacker in
the operational environment. For any vulnerabilities for which an
exploitation is determined, the evaluator performs an attack potential
calculation to determine that the exploitation is appropriate to the level of
attack potential assumed for the attacker.
1940
The approach described below is to be applied whenever it is necessary to
calculate attack potential, unless the evaluation authority provides mandatory
guidance that an alternative approach is to be applied. The values given in
Tables 3 and 4 below are not mathematically proven. Therefore, the values
given in these example tables may need to be adjusted according to the
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technology type and specific environments. Guidance from the evaluation
authority should be sought.
B.4
Calculating attack potential
B.4.1
Application of attack potential
1941
Attack potential is a function of expertise, resources and motivation. There
are multiple methods of representing and quantifying these factors. Also,
there may be other factors that are applicable for particular TOE types.
B.4.1.1
Treatment of motivation
1942
Motivation is an attack potential factor that can be used to describe several
aspects related to the attacker and the assets the attacker desires. Firstly,
motivation can imply the likelihood of an attack - one can infer from a threat
described as highly motivated that an attack is imminent, or that no attack is
anticipated from an un-motivated threat. However, except for the two
extreme levels of motivation, it is difficult to derive a probability of an attack
occurring from motivation.
1943
Secondly, motivation can imply the value of the asset, monetarily or
otherwise, to either the attacker or the asset holder. An asset of very high
value is more likely to motivate an attack compared to an asset of little value.
However, other than in a very general way, it is difficult to relate asset value
to motivation because the value of an asset is subjective - it depends largely
upon the value an asset holder places on it.
1944
Thirdly, motivation can imply the expertise and resources with which an
attacker is willing to effect an attack. One can infer that a highly motivated
attacker is likely to acquire sufficient expertise and resources to defeat the
measures protecting an asset. Conversely, one can infer that an attacker with
significant expertise and resources is not willing to effect an attack using
them if the attacker's motivation is low.
1945
During the course of preparing for and conducting an evaluation, all three
aspects of motivation are at some point considered. The first aspect,
likelihood of attack, is what may inspire a developer to pursue an evaluation.
If the developer believes that the attackers are sufficiently motivated to
mount an attack, then an evaluation can provide assurance of the ability of
the TOE to thwart the attacker's efforts. Where the operational environment
is well defined, for example in a system evaluation, the level of motivation
for an attack may be known, and will influence the selection of
countermeasures.
1946
Considering the second aspect, an asset holder may believe that the value of
the assets (however measured) is sufficient to motivate attack against them.
Once an evaluation is deemed necessary, the attacker's motivation is
considered to determine the methods of attack that may be attempted, as well
as the expertise and resources used in those attacks. Once examined, the
developer is able to choose the appropriate assurance level, in particular the
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AVA requirement components, commensurate with the attack potential for
the threats. During the course of the evaluation, and in particular as a result
of completing the vulnerability assessment activity, the evaluator determines
whether or not the TOE, operating in its operational environment, is
sufficient to thwart attackers with the identified expertise and resources.
1947
It may be possible for a PP author to quantify the motivation of an attacker,
as the PP author has greater knowledge of the operational environment in
which the TOE (conforming to the requirements of the PP) is to be placed.
Therefore, the motivation could form an explicit part of the expression of the
attack potential in the PP, along with the necessary methods and measures to
quantify the motivation.
B.4.2
Characterising attack potential
1948
This section examines the factors that determine attack potential, and
provides some guidelines to help remove some of the subjectivity from this
aspect of the evaluation process.
B.4.2.1
Determining the attack potential
1949
The determination of the attack potential for an attack corresponds to the
identification of the effort required to create the attack, and to demonstrate
that it can be successfully applied to the TOE (including setting up or
building any necessary test equipment), thereby exploiting the vulnerability
in the TOE. The demonstration that the attack can be successfully applied
needs to consider any difficulties in expanding a result shown in the
laboratory to create a useful attack. For example, where an experiment
reveals some bits or bytes of a confidential data item (such as a key), it is
necessary to consider how the remainder of the data item would be obtained
(in this example some bits might be measured directly by further
experiments, while others might be found by a different technique such as
exhaustive search). It may not be necessary to carry out all of the
experiments to identify the full attack, provided it is clear that the attack
actually proves that access has been gained to a TOE asset, and that the
complete attack could realistically be carried out in exploitation according to
the AVA_VAN component targeted. In some cases the only way to prove
that an attack can realistically be carried out in exploitation according to the
AVA_VAN component targeted is to perform completely the attack and this
shall be rated. One of the outputs from the identification of a potential
vulnerability is assumed to be a script that gives a step-by-step description of
how to carry out the attack that can be used in the exploitation of the
vulnerability on another instance of the TOE.
1950
In many cases, the evaluators will estimate the parameters for exploitation,
rather than carry out the full exploitation. The estimates and their rationale
will be documented in the ETR.
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B.4.2.2
Factors to be considered
1951
The following factors should be considered during analysis of the attack
potential required to exploit a vulnerability:
a)
Time taken to identify and exploit (Elapsed Time);
b)
Specialist technical expertise required (Specialist Expertise);
c)
Knowledge of the TOE design and operation (Knowledge of the
TOE);
d)
Window of opportunity;
e)
IT hardware/software or other equipment required for exploitation.
1952
In many cases these factors are not independent, but may be substituted for
each other in varying degrees. For example, expertise or hardware/software
may be a substitute for time. A discussion of these factors follows. (The
levels of each factor are discussed in increasing order of magnitude.) When it
is the case, the less “expensive” combination shall be considered in
exploitation phase.
1953
Elapsed time is the total amount of time taken by an attacker to identify that
a particular potential vulnerability may exist in the TOE, to develop an attack
method and to sustain effort required to mount the attack against the TOE.
When considering this factor, the worst case scenario should be used to
estimate the amount of time required. The identified amount of time is as
follows:
1954
a)
less than one day;
b)
between one day and one week;
c)
between one week and two weeks;
d)
between two weeks and one month;
e)
each additional month up to 6 months leads to an increased value;
f)
more than 6 months.
Specialist expertise refers to the level of generic knowledge of the
underlying principles, product type or attack methods (e.g. Internet protocols,
Unix operating systems, buffer overflows). The identified levels are as
follows:
a)
Laymen are unknowledgeable compared to experts or proficient
persons, with no particular expertise;
b)
Proficient persons are knowledgeable in that they are familiar with
the security behaviour of the product or system type;
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c)
Experts are familiar with the underlying algorithms, protocols,
hardware, structures, security behaviour, principles and concepts of
security employed, techniques and tools for the definition of new
attacks, cryptography, classical attacks for the product type, attack
methods, etc. implemented in the product or system type.
d)
The level “Multiple Expert” is introduced to allow for a situation,
where different fields of expertise are required at an Expert level for
distinct steps of an attack.
1955
It may occur that several types of expertise are required. By default, the
higher of the different expertises factors is chosen. In very specific cases, the
“multiple expert” level could be used but it should be noted that the expertise
must concern fields that are strictly different like for example HW
manipulation and cryptography.
1956
Knowledge of the TOE refers to specific expertise in relation to the TOE.
This is distinct from generic expertise, but not unrelated to it. Identified
levels are as follows:
a)
Public information concerning the TOE (e.g. as gained from the
Internet);
b)
Restricted information concerning the TOE (e.g. knowledge that is
controlled within the developer organisation and shared with other
organisations under a non-disclosure agreement)
c)
Sensitive information about the TOE (e.g. knowledge that is shared
between discreet teams within the developer organisation, access to
which is constrained only to members of the specified teams);
d)
Critical information about the TOE (e.g. knowledge that is known by
only a few individuals, access to which is very tightly controlled on a
strict need to know basis and individual undertaking).
1957
The knowledge of the TOE may graduate according to design abstraction,
although this can only be done on a TOE by TOE basis. Some TOE designs
may be public source (or heavily based on public source) and therefore even
the design representation would be classified as public or at most restricted,
while the implementation representation for other TOEs is very closely
controlled as it would give an attacker information that would aid an attack
and is therefore considered to be sensitive or even critical.
1958
It may occur that several types of knowledge are required. In such cases, the
higher of the different knowledge factors is chosen.
1959
Window of opportunity (Opportunity) is also an important consideration, and
has a relationship to the Elapsed Time factor. Identification or exploitation
of a vulnerability may require considerable amounts of access to a TOE that
may increase the likelihood of detection. Some attack methods may require
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considerable effort off-line, and only brief access to the TOE to exploit.
Access may also need to be continuous, or over a number of sessions.
1960
For some TOEs the Window of opportunity may equate to the number of
samples of the TOE that the attacker can obtain. This is particularly relevant
where attempts to penetrate the TOE and undermine the SFRs may result in
the destruction of the TOE preventing use of that TOE sample for further
testing, e.g. hardware devices. Often in these cases distribution of the TOE is
controlled and so the attacker must apply effort to obtain further samples of
the TOE.
1961
For the purposes of this discussion:
a)
unnecessary/unlimited access means that the attack doesn't need any
kind of opportunity to be realised because there is no risk of being
detected during access to the TOE and it is no problem to access the
number of TOE samples for the attack;
b)
easy means that access is required for less than a day and that the
number of TOE samples required to perform the attack is less than
ten;
c)
moderate means that access is required for less than a month and that
the number of TOE samples required to perform the attack is less
than one hundred;
d)
difficult means that access is required for at least a month or that the
number of TOE samples required to perform the attack is at least one
hundred;
e)
none means that the opportunity window is not sufficient to perform
the attack (the length for which the asset to be exploited is available
or is sensitive is less than the opportunity length needed to perform
the attack - for example, if the asset key is changed each week and
the attack needs two weeks); another case is, that a sufficient number
of TOE samples needed to perform the attack is not accessible to the
attacker - for example if the TOE is a hardware and the probability to
destroy the TOE during the attack instead of being successful is very
high and the attacker has only access to one sample of the TOE.
1962
Consideration of this factor may result in determining that it is not possible
to complete the exploit, due to requirements for time availability that are
greater than the opportunity time.
1963
IT hardware/software or other equipment refers to the equipment required
to identify or exploit a vulnerability.
a)
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Standard equipment is readily available to the attacker, either for the
identification of a vulnerability or for an attack. This equipment may
be a part of the TOE itself (e.g. a debugger in an operating system),
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or can be readily obtained (e.g. Internet downloads, protocol analyser
or simple attack scripts).
b)
Specialised equipment is not readily available to the attacker, but
could be acquired without undue effort. This could include purchase
of moderate amounts of equipment (e.g. power analysis tools, use of
hundreds of PCs linked across the Internet would fall into this
category), or development of more extensive attack scripts or
programs. If clearly different test benches consisting of specialised
equipment are required for distinct steps of an attack this shall be
rated as bespoke.
c)
Bespoke equipment is not readily available to the public as it may
need to be specially produced (e.g. very sophisticated software), or
because the equipment is so specialised that its distribution is
controlled, possibly even restricted. Alternatively, the equipment may
be very expensive.
d)
The level “Multiple Bespoke” is introduced to allow for a situation,
where different types of bespoke equipment are required for distinct
steps of an attack.
1964
Specialist expertise and Knowledge of the TOE are concerned with the
information required for persons to be able to attack a TOE. There is an
implicit relationship between an attacker's expertise (where the attacker may
be one or more persons with complementary areas of knowledge) and the
ability to effectively make use of equipment in an attack. The weaker the
attacker's expertise, the lower the potential to use equipment (IT
hardware/software or other equipment). Likewise, the greater the expertise,
the greater the potential for equipment to be used in the attack. Although
implicit, this relationship between expertise and the use of equipment does
not always apply, for instance, when environmental measures prevent an
expert attacker's use of equipment, or when, through the efforts of others,
attack tools requiring little expertise to be effectively used are created and
freely distributed (e.g. via the Internet).
B.4.2.3
Calculation of attack potential
1965
Table 3 identifies the factors discussed in the previous section and associates
numeric values with the total value of each factor.
1966
Where a factor falls close to the boundary of a range the evaluator should
consider use of an intermediate value to those in the table. For example, if
twenty samples are required to perform the attack then a value between one
and four may be selected for that factor, or if the design is based on a
publicly available design but the developer has made some alterations then a
value between zero and four should be selected according to the evaluator's
view of the impact of those design changes. The table is intended as a guide.
1967
The “**” specification in the table in considering Window of Opportunity is
not to be seen as a natural progression from the timescales specified in the
preceding ranges associated with this factor. This specification identifies that
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for a particular reason the potential vulnerability cannot be exploited in the
TOE in its intended operational environment. For example, access to the
TOE may be detected after a certain amount of time in a TOE with a known
environment (i.e. in the case of a system) where regular patrols are
completed, and the attacker could not gain access to the TOE for the required
two weeks undetected. However, this would not be applicable to a TOE
connected to the network where remote access is possible, or where the
physical environment of the TOE is unknown.
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Factor
Value
Elapsed Time
<= one day
<= one week
<= two weeks
<= one month
<= two months
<= three months
<= four months
<= five months
<= six months
> six months
Expertise
Layman
Proficient
Expert
Multiple experts
Knowledge of TOE
Public
Restricted
Sensitive
Critical
Window of Opportunity
Unnecessary / unlimited access
Easy
Moderate
Difficult
None
Equipment
Standard
Specialised
Bespoke
Multiple bespoke
0
1
2
4
7
10
13
15
17
19
0
3*(1)
6
8
0
3
7
11
0
1
4
10
**(2)
0
4(3)
7
9
(1)
When several proficient persons are required to complete the attack path, the resulting
level of expertise still remains “proficient” (which leads to a 3 rating).
(2)
Indicates that the attack path is not exploitable due to other measures in the intended
operational environment of the TOE.
(3)
If clearly different test benches consisting of specialised equipment are required for
distinct steps of an attack, this should be rated as bespoke.
Table 3 Calculation of attack potential
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1968
1969
To determine the resistance of the TOE to the potential vulnerabilities
identified the following steps should be applied:
a)
Define the possible attack scenarios {AS1, AS2, ..., ASn} for the
TOE in the operational environment.
b)
For each attack scenario, perform a theoretical analysis and calculate
the relevant attack potential using Table 3.
c)
For each attack scenario, if necessary, perform penetration tests in
order to confirm or to disprove the theoretical analysis.
d)
Divide all attack scenarios {AS1, AS2, ..., ASn} into two groups:
1)
the attack scenarios having been successful (i.e. those that
have been used to successfully undermine the SFRs), and
2)
the attack scenarios that have been demonstrated to be
unsuccessful.
e)
For each successful attack scenario, apply Table 4 and determine,
whether there is a contradiction between the resistance of the TOE
and the chosen AVA_VAN assurance component, see the last column
of Table 4.
f)
Should one contradiction be found, the vulnerability assessment will
fail, e.g. the author of the ST chose the component AVA_VAN.5 and
an attack scenario with an attack potential of 21 points (high) has
broken the security of the TOE. In this case the TOE is resistant to
attacker with attack potential 'Moderate', this contradicts to
AVA_VAN.5, hence, the vulnerability assessment fails.
The “Values” column of Table 3 indicates the range of attack potential
values (calculated using Table 4) of an attack scenario that results in the
SFRs being undermined.
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Attack
potential
Values required to
exploit
scenario:
TOE
resistant to
attackers
with attack
potential
of:
Meets assurance
components::
0-9
Basic
No rating
-
10-13
EnhancedBasic
Basic
AVA_VAN.1,
AVA_VAN.2
14-19
Moderate
EnhancedBasic
20-24
High
Moderate
=>25
Beyond
High
High
AVA_VAN.1,
AVA_VAN.2,
AVA_VAN.3
AVA_VAN.1,
AVA_VAN.2,
AVA_VAN.3,
AVA_VAN.4
AVA_VAN.1,
AVA_VAN.2,
AVA_VAN.3,
AVA_VAN.4,
AVA_VAN.5
Failure of
components:
AVA_VAN.1,
AVA_VAN.2,
AVA_VAN.3,
AVA_VAN.4,
AVA_VAN.5
AVA_VAN.3,
AVA_VAN.4,
AVA_VAN.5
AVA_VAN.4,
AVA_VAN.5
AVA_VAN.5
-
Table 4 Rating of vulnerabilities and TOE resistance
1970
An approach such as this cannot take account of every circumstance or
factor, but should give a better indication of the level of resistance to attack
required to achieve the standard ratings. Other factors, such as the reliance
on unlikely chance occurrences are not included in the basic model, but can
be used by an evaluator as justification for a rating other than those that the
basic model might indicate.
1971
It should be noted that whereas a number of vulnerabilities rated individually
may indicate high resistance to attack, collectively the combination of
vulnerabilities may indicate that overall a lower rating is applicable. The
presence of one vulnerability may make another easier to exploit.
1972
If a PP/ST author wants to use the attack potential table for the determination
of the level of attack the TOE should withstand (selection of Vulnerability
analysis (AVA_VAN) component), he should proceed as follows: For
different types of attacker and/or different types of attack the author has in
mind, several passes through Table 3 should be made to determine the
different values of attack potential understood for each type of attacker. The
PP/ST author then considers the highest value obtained in order to determine
the claimed level of resistance from Table 4.
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B.5
Example calculation for direct attack
1973
Mechanisms subject to direct attack are often vital for system security and
developers often strengthen these mechanisms. As an example, a TOE might
use a simple pass number authentication mechanism that can be overcome by
an attacker who has the opportunity to repeatedly guess another user's pass
number. The system can strengthen this mechanism by restricting pass
numbers and their use in various ways. During the course of the evaluation
an analysis of this direct attack could proceed as follows:
1974
Information gleaned from the ST and design evidence reveals that
identification and authentication provides the basis upon which to control
access to network resources from widely distributed terminals. Physical
access to the terminals is not controlled by any effective means. The duration
of access to a terminal is not controlled by any effective means. Authorised
users of the system choose their own pass numbers when initially authorised
to use the system, and thereafter upon user request. The system places the
following restrictions on the pass numbers selected by the user:
a)
the pass number must be at least four and no greater than six digits
long;
b)
consecutive numerical sequences are disallowed (such as 7,6,5,4,3);
c)
repeating digits is disallowed (each digit must be unique).
1975
Guidance provided to the users at the time of pass number selection is that
pass numbers should be as random as possible and should not be affiliated
with the user in some way - a date of birth, for instance.
1976
The pass number space is calculated as follows:
1977
a)
Patterns of human usage are important considerations that can
influence the approach to searching a password space. Assuming the
worst case scenario and the user chooses a number comprising only
four digits, the number of pass number permutations assuming that
each digit must be unique is:
b)
The number of possible increasing sequences is seven, as is the
number of decreasing sequences. The pass number space after
disallowing sequences is:
Based on further information gleaned from the design evidence, the pass
number mechanism is designed with a terminal locking feature. Upon the
sixth failed authentication attempt the terminal is locked for one hour. The
failed authentication count is reset after five minutes so that an attacker can
Page 404 of 405
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Vulnerability Assessment (AVA)
at best attempt five pass number entries every five minutes, or 60 pass
number entries every hour.
1978
On average, an attacker would have to enter 2513 pass numbers, over 2513
minutes, before entering the correct pass number. The average successful
attack would, as a result, occur in slightly less than:
1979
Using either of the approaches to calculate attack potential described above,
it is possible that a layman can defeat the mechanism within days (given easy
access to the TOE), with the use of standard equipment, and with no
knowledge of the TOE, giving a value of 1. Given the resulting sum, 1, the
attack potential required to effect a successful attack is not rated, as it falls
below that considered to be Basic.
September 2006
Version 3.1
Page 405 of 405
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