Research Report on the security of MFPs v2.0(2013-03)

Research Report on the security of MFPs v2.0(2013-03)
Research Report on the Security of MFPs
V2.0
March 2013
English translation V1.0
September 2013
JISEC, IT Security Center,
Technology Headquarters, IPA
Notice:
This document is an English translation of the original report in Japanese,
published by the Japan Information Technology Security Evaluation and
Certification Scheme under IPA. Please note that URLs contained in this report
were effective when the Japanese version was published, but some links may no
longer work.
The product names in this report are generally registered trademarks, trademarks, or
brand names of companies.
TM, ©, and ® are omitted in this report.
1
Table of Contents
Table of Contents
Table of Contents .................................................................................................................. 2
List of Figures ....................................................................................................................... 5
List of Tables ......................................................................................................................... 5
1.
2.
Introduction....................................................................................................................... 8
1.1
What is MFP? ......................................................................................................... 8
1.2
Background of this report ...................................................................................... 8
1.3
Purpose of this report............................................................................................. 9
1.4
Target readers ........................................................................................................ 9
1.5
Assumptions of this report .................................................................................... 9
1.6
Definitions of main terms .................................................................................... 10
Research and Analysis Methods ........................................................................................ 12
2.1
Arrangement of the usage and functions of the MFP ....................................... 13
2.2
Arrangement of the functional blocks ................................................................ 13
2.3
Specifying the data exchanged between functional blocks as assets to be
protected ....................................................................................................................... 13
3.
4.
2.4
Listing threats and vulnerabilities by each asset.............................................. 14
2.5
Detailed explanations of notable vulnerabilities ............................................... 14
Usage and Functions of the MFP....................................................................................... 15
3.1
Development history of the MFP ........................................................................ 15
3.2
Security required for the MFP ............................................................................ 16
3.3
Life-cycle in an environment of MFP use ........................................................... 17
3.4
MFP from the viewpoint of information systems............................................... 19
3.5
MFP system configuration examples .................................................................. 20
3.6
Hardware inside the MFP ................................................................................... 22
3.7
Software inside the MFP ..................................................................................... 27
Data Flow when Using the MFP ....................................................................................... 33
4.1
Printing ................................................................................................................. 34
4.2
Load distribution printing ................................................................................... 35
4.3
Scanning to X, faxing ........................................................................................... 36
4.4
Receiving fax......................................................................................................... 38
4.5
Copying ................................................................................................................. 39
4.6
Setting the configuration management information and acquisition (console)40
2
Table of Contents
4.7
Setting the configuration management information and acquisition via remote
communication ............................................................................................................. 41
4.8
5.
6.
Maintenance, parts replacement, billing, and diagnosis .................................. 42
Assets to be protected by the MFP .................................................................................... 43
5.1
Primary assets in an environment of MFP use.................................................. 43
5.2
Secondary assets as targets to be protected to use the MFP ............................ 43
5.3
Main unit of the MFP .......................................................................................... 44
5.4
Run-time data ....................................................................................................... 45
5.5
Other systems ....................................................................................................... 46
5.6
Activation results information ............................................................................ 48
Vulnerabilities assumed from threats ................................................................................. 49
6.1
Extractions of the threats .................................................................................... 49
6.2
Those who should take measures against threats ............................................. 49
6.3
Main unit (Hardware) .......................................................................................... 51
6.4
Software inside the MFP ..................................................................................... 54
6.5
Usage license, maintenance license .................................................................... 58
6.6
Removable media (for users, for administrators) .............................................. 60
6.7
Job data (Image, destination, control) ................................................................ 62
6.8
Management/configuration information............................................................. 67
6.9
Digital certificate, ID, password, session information ...................................... 70
6.10 Accurate time........................................................................................................ 76
6.11 Original papers, prints ........................................................................................ 80
6.12 Shared files inside the MFP ................................................................................ 82
6.13 Usage history, audit records ................................................................................ 86
6.14 Billing information for MFP use ......................................................................... 89
6.15 Communication system (including Switch, DHCP, DNS, NTP) ....................... 92
6.16 Remote management system............................................................................... 96
6.17 User terminal ..................................................................................................... 101
6.18 Accumulation and external processing (Spooler, shared folders, emails, other
business systems) ...................................................................................................... 104
7.
Detailed description of vulnerabilities ..................................................................... 108
7.1
Assumptions about attacks ............................................................................... 108
7.2
Seriousness and attack potential evaluation ................................................... 108
7.3
Problems with data protection of the storage media ........................................110
7.4
Information leakage caused by equipped SSD ..................................................115
7.5
Problems of access to local maintenance interfaces .........................................119
3
Table of Contents
7.6
Problems of resetting to the factory settings ................................................... 123
7.7
Problems from exploiting the firmware update function ................................ 127
7.8
Problems due to vulnerabilities of the embedded OS ...................................... 132
7.9
Vulnerability related to SDK (Software Development Kit)............................. 136
7.10 Problems due to vulnerabilities of applications introduced to the user
terminals .................................................................................................................... 140
7.11 Problems due to vulnerabilities of many protocols .......................................... 144
7.12 Concerning vulnerabilities of proprietary MFP protocols ............................... 156
7.13 Problems of intrusion via driver protocol ......................................................... 161
7.14 Problems due to vulnerabilities of page description language ....................... 168
7.15 Problems due to vulnerabilities of the web management console .................. 173
7.16 Problems from the misuse of web-based maintenance functions ................... 180
7.17 Problems of using external authentication ...................................................... 185
7 18 Problems of malware infected files mixing into the MFP ........................................... 189
8.
Other security measures ........................................................................................... 194
8.1
Problems of manufacture by developers and the time of delivery.................. 194
8.2
Information provision to users through guidance ........................................... 194
8.3
Outbound measures on the MFP ...................................................................... 194
9.
Discussion of the vulnerabilities related to new functions ..................................... 196
9.1
10.
Problems of the implementation deficiencies of SAML ............................................. 196
Conclusion ............................................................................................................... 200
4
List of Figures
List of Figures
Figure 2-1 Overview of the research and analysis method ........................................................ 12
Figure 3-1 Development history of the MFP ........................................................................... 15
Figure 3-2 Functions and security required for the MFP ........................................................... 16
Figure 3-3 Life-cycle in the usage environment of the MFP ..................................................... 18
Figure 3-4 MFP from the viewpoint of an information system .................................................. 19
Figure 3-5 MFP system configuration examples ...................................................................... 21
Figure 3-6 Hardware inside the MFP ...................................................................................... 22
Figure 3-7 Hardware inside the MFP - Substrate and main interface.......................................... 24
Figure 3-8 Hardware inside the MFP - Connection between units or modules ............................ 25
Figure 3-9 Software inside the MFP ....................................................................................... 27
Figure 4-1 Configuration diagram of data flow when using the MFP......................................... 33
Figure 4-2 Data flow for printing ........................................................................................... 34
Figure 4-3 Data flow for load distribution printing................................................................... 35
Figure 4-4 Scanning to X, faxing data flow ............................................................................. 36
Figure 4-5 Data flow for receiving fax .................................................................................... 38
Figure 4-6 Data flow for copying ........................................................................................... 39
Figure 4-7 Data flow for setting the configuration management information and acquisition ....... 40
Figure 4-8 Data flow for setting the configuration management information and........................ 41
Figure 4-9 Data flow for maintenance, parts replacement, billing, and diagnosis ........................ 42
Figure 5-1 Data flow when using MFP ................................................................................... 43
Figure 6-1 Requirements for information security - Seven types ............................................... 49
Figure 7-1 Attack potential diagram...................................................................................... 109
Figure 7-2 Relationship between logical blocks and physical blocks ........................................115
Figure 7-3 Publicly available operations for entering maintenance mode ................................. 120
Figure 7-4 Published procedures for putting back the factory settings (overseas MFPs) ............ 124
Figure 7-5 Excerpt from the firmware update by using the LPR command .............................. 127
Figure 7-6 Public information of the firmware verification methods........................................ 128
Figure 7-7 Unauthorized application installation using SDK................................................... 137
Figure 7-8 Examples of files that are installed to attack user terminals .................................... 140
Figure 7-9 A list of communications protocols that are commonly used on the MFP ................. 144
Figure 7-10 Example of source code that performs vulnerable protocol processing .................. 157
Figure 7-11 Improved source code that performs protocol processing ..................................... 158
Figure 7-12 Example of intrusion via driver protocol LPR ..................................................... 162
5
List of Figures
Figure 7-13 Example of a sequence of intrusion by driver protocol LPR command .................. 163
Figure 7-14 Attack using a PJL command (Directory traversal) .............................................. 169
Figure 7-15 Example of attack by CSRF............................................................................... 177
Figure 7-16 Example of method for accessing the maintenance interfaces (http) ...................... 181
Figure 7-17 Example of a sequence for exploiting a maintenance interface using CSRF ........... 182
Figure 7-18 Kerberos authentication image ........................................................................... 186
Figure 7-19 Image of malware propagation to the user terminals from the MFP....................... 190
Figure 7-20 Example of security concepts of MFP vendors .................................................... 191
Figure 9-1 Image of authentication cooperation between Active Directory and cloud businesses 197
Figure 9-2 Image of unauthorized authentication by MiM ...................................................... 198
6
List of Tables
List of Tables
Table 5-1 Secondary assets as targets to be protected to use the MFP......................................... 44
Table 7-1 Examples of vulnerabilities of the embedded Linux................................................. 132
Table 7-2 Major driver protocols used on the MFP ................................................................. 161
Table 7-3 PJL commands related to file system operations ...................................................... 168
7
Research Report on the Security of MFPs
1. Introduction
1. Introduction
1.1
What is MFP?
MFP stands for Multi-Function Peripheral, Multi-Function Printer, or Multi-Function
Product.
MFPs in this report refer to peripherals with the integrated functions, such as copy, print,
scan, and fax.
The research targets of this report are the MFPs that require a high degree of information
security functionality in such office environments as businesses and government agencies.
Such MFPs are categorized in the Japanese product catalogs as “digital multifunction
device,” “color multifunction device” or “monochrome multifunction device,” by their
functions, but some are simply called “multifunction device.” In this report, it is referred
to as “MFP,” which is an English abbreviation.
1.2
Background of this report
MFPs are IT products with security functions that represent Japan, and Japan has multiple
vendors who are suppliers of MFPs to the world.
The MFP as a simple general office machine has been developed to have a role as a hub of
information distribution in the office by providing connections to the LAN and
information storage, etc., in recent years. Correspondingly, in response to the increasing
demand for information security for the MFP, MFP vendors focus on the quality
improvement of the information security functions, and have a number of certifications
under the “Japan Information Technology Security Evaluation and Certification Scheme”
operated by IPA.1
On the other hand, the MFP is becoming a more frequent target of attacks. The
vulnerability that causes unauthorized operation of the MFP by exploiting the MFP’s
remote control function was published in November 2011.2 Due to the multiple
functionality and sophistication associated with such improved conveniences as usage in
the Internet environment, including the cloud computing environment, and support for
smart devices, etc., more opportunities for attacking MFPs have been increasing in recent
years. In this situation, even for the information security aspects, MFP vendors shall
consider comprehensive countermeasures from the design stage against a wide variety of
threats, including the risks of using a platform with the impact of known vulnerabilities as
well as threats due to the network connection.
In general, the MFP is not recognized as an IT device whose security is important. There
are cases where potential problems, such as an oversight at the design stage and problems
with usage that the developers had not expected, are recognized later as vulnerabilities, or
where configurations appropriate to the installation conditions and management of
confidential information are not implemented (e.g., access methods to maintenance
interfaces that no user could know, and administrator interface with access control have
been published on the Internet).
1
http://www.ipa.go.jp/security/jisec/index.html
2
http://redtape.nbcnews.com/_news/2011/11/29/9076395-exclusive-millions-of-printers-open-to-devast
ating-hack-attack-researchers-say
8
Research Report on the Security of MFPs
1.3
1. Introduction
Purpose of this report
The last research report (V1.0) comprehensively identified the vulnerabilities of the MFP
regarding its security requirements, and described in detail the kinds of threats, the extent
of attack potentials, the kinds of possible damages, and effective countermeasures for
those, with respect to some notable items.
In this report, the viewpoints regarding the vulnerabilities that shall be noted in order to
operate or develop the MFP are explained comprehensively and in detail. Specifically, the
focus is on the vulnerabilities that create many opportunities for attacks, and the
vulnerabilities that have existed for a long time but have been neglected, as they were not
recognized by the parties involved. This report also researches from various perspectives
and explains the vulnerabilities, which shall be considered initially for the MFP.
For the attack methods against these vulnerabilities explained in Chapter 7 and subsequent
chapters, actual verification was conducted in the course of this research, and it includes
successful attacks against some MFPs. Therefore, this report explains inspection methods,
which are needed by parties involved to confirm the presence of vulnerabilities to the
specific MFP, as well.
By recognizing the vulnerabilities described in this report, guidelines shall be provided for
efforts to ensure security during the development process for vendors, countermeasures
against problems in the operating environment as well as misuse by users, and measures to
take for the suspected vulnerabilities in general functions of the MFP. Therefore, the
purpose of this report is to improve the inspection standards of security inspection by
utilizing this report.
1.4
Target readers
Target readers for this report are mainly developers who plan, design, and develop MFPs,
as well as MFP users and evaluators who examine the MFP security functions.
1.5
Assumptions of this report
In this report, we assume an environment where information assets that can lead to a
disadvantage to users (organizations) are stored when they are leaked, so that malicious
users (attackers) can gain access to the information assets through contacts with the MFP
on a scope that is not suspicious, or through the operation panel of the network or the MFP,
assuming such MFP is connected to the intranet. In such an environment, MFPs that
combine functions such as web server or file server are consequently required to ensure
the security equivalent to the web server or file server.
The assumption of this report is to use high-end models among MFPs with a variety of
authentication functions and the SDK. Some MFPs are not originally equipped with the
functions that lead to the vulnerabilities described in this report. In addition, in case of
securely using the certified products under the “Japan Information Technology Security
Evaluation and Certification Scheme,” for example, some MFPs can be used by turning
off some functions that lead to vulnerabilities before operation begins.
Because vulnerabilities are comprehensively identified in this report, readers should be
aware that some items may not be relevant, depending on the MFP to be installed, the
usage environment, or the security policy of the office.
9
Research Report on the Security of MFPs
1.6
1. Introduction
Definitions of main terms
Definitions of main terms in this report are as follows. The meanings of terms other than
those described here are supplemented in the footnotes, etc., when they appear:
Term
MFP
Japan Information
Technology Security
Evaluation and
Certification Scheme
Japan Cryptographic
Module Validation
Program
CVSS
CEM
SSD
SLC chip
MLC chip
Maintenance interface
Definition
Abbreviation for Multi-Function Peripheral, Multi-Function Printer, or
Multi-Function Product. It may also be called SPC (Scan Print Copy), AIO
(All In One), or MFD (Multi-Function Device). MFPs in this report refer to
peripherals with the integrated functions, such as copy, print, scan, and fax.
A Scheme in Japan: in the procurement of IT products by the government,
etc., a third party (Evaluation Facility) evaluates appropriateness and
reliability of the security functions of the IT products, based on ISO/IEC
15408, which is the international standard for security evaluation criteria,
and the Certification Body certifies the evaluation results.
Abbr.: JISEC (Japan Information Technology Security Evaluation and
Certification Scheme)
A Scheme in Japan: a third party conducts tests and certifies a cryptographic
module, which is composed of hardware or software, etc., that is
implemented with security functions, such as encryption functions, hash
functions, and authorized signature functions, etc., listed as e-Government
recommended ciphers, for appropriate protection of important information,
such as security functions, cryptographic keys, and passwords, etc., that are
stored inside.
Abbr.: JCMVP (Japan Cryptographic Module Validation Program)
Abbreviation for Common Vulnerability Scoring System. It is an open,
comprehensive, and versatile evaluation method for the vulnerabilities of
information systems, and provides common evaluation methods without
relying on MFP vendors.
The standard that discloses the methodology used in the evaluation based on
ISO/IEC 15408. Abbreviation for Common Evaluation Methodology. The
formal name is Common Methodology for Information Technology Security
Evaluation, and it is issued as ISO standard (ISO/IEC 18045).
A storage device using a flash memory as a storage medium. It is equipped
with the same connection interface as that of a hard disk drive (HDD), and
can be used as an alternative to a hard disk.
Abbreviation for Solid State Drive.
One of the data recording systems in NAND-type flash memory. It stores 1
bit of data consisting of binary value of storage elements (memory cells).
SLC is an abbreviation for Single Level Cell.
One of the data recording systems in NAND-type flash memory. It stores
multi-bits of data consisting of three or more storage elements (memory
cells).
MLC is an abbreviation for Multiple Level Cell.
An interface used for maintenance of the MFP, such as setting and
initialization of the MFP, and setting the administrator password, etc. It is
broadly classified into two; a local maintenance interface with which
maintenance personnel directly operate the MFP, and a remote maintenance
interface with which maintenance personnel remotely operate the MFP.
10
Research Report on the Security of MFPs
LPR
Page description
language
Reverse-Engineering
Cross compiler
Backdoor
Buffer overflow
Directory traversal
Remote shell
Port scan
Black-box testing
1. Introduction
A printing protocol via a TCP/IP network. LPR protocol is used to carry out
printing using the printer or the MFP that is connected to a print server on
the network, and it is specified in RFC 1179.
A language which instructs the printer or the MFP by describing the output
image when printing images or documents from a user terminal such as a
personal computer.
To disclose the mechanism, specification, purpose, components, and
elements of the technology, etc., of hardware or software, etc., by
decomposing or analyzing.
A compiler to generate an executable program on a different platform from
a development platform.
Intrusion pathway from the back, which is created on a server or personal
computer, etc. Some are created at the time of development, and some are
created by malware or unauthorized access by an attacker, etc.
A vulnerability in which the data, whose size is greater than what is
ensured, is written into the buffer when writing to the memory area
allocated statically or dynamically. There is a possibility that privilege
escalation or unauthorized access is performed due to this vulnerability.
The attack method which accesses files in the directory that the
administrator does not assume (authorize) by specifying relative path, etc.
CUI (Character User Interface) program that executes shell commands on
another computer via network.
To examine service availability externally via network, etc.
To examine the functionality, etc., externally without peering into its
internal structures. The antonym is white-box testing.
11
Research Report on the Security of MFPs
2. Research and Analysis Methods
2. Research and Analysis Methods
In order to comprehensively extract vulnerabilities related to the MFP, this material
introduces a research and analysis method as in the following Figure 2-1. From the left,
“1. Functions and usage” is identified, and “2. Division of functions,” and “3. Protected
items” are identified. From “4. Threat and vulnerability analysis,” “5. Assumed
vulnerability list” and “6. Details of vulnerabilities unique to the MFP” on the right-hand
side of the figure are produced as achievements. Details of vulnerabilities unique to the
MFP explain the details of some vulnerabilities extracted from the assumed vulnerability
list in regard to the configuration diagram, background, and causes.
Figure 2-1 Overview of the research and analysis method
The procedure for this research specifies a list of threats to the information system in the
usage environment of the MFP. A list of threats shall be sorted out according to the
procedure of “threat modeling,”3 which has been introduced as a “threat exposure
procedure” in the IPA “Secure Programming Course.” Threat modeling specifies the data
flow from the system configuration diagram, and identifies the threats while tracing the
boundaries of interfaces.
In this research, in order to specify the system configuration diagram, usage and functions
of the MFP are shown in “1. Functions and usage” on the left in the figure. Next, shared
functions on the systems of internal and external MFPs are identified in “2. Division of
functions.” The data flow is organized according to the usage of the MFP for specifying
the information assets in order, which are primary assets to secondary assets, in the “3.
Protected items.” In “4. Threat and vulnerability analysis,” as requirements for information
3
Threat modeling – IPA “Secure Programming Course” threat modeling
http://www.ipa.go.jp/security/awareness/vendor/programmingv2/contents/c101.html
“Threat Modeling - Application security architecture” Frank Swiderski and others, translation by
Yoko Watabe, Nikkei Business Publications, Inc. 2005
12
Research Report on the Security of MFPs
2. Research and Analysis Methods
security in general, confidentiality, integrity and availability of ISO/IEC 27001, which are
the standards of information security management, and four requirements (authenticity,
accountability, non-repudiation, reliability) defined as optional, are applied. Anything
identified as breaking these requirements is considered a threat.4
The purpose of this research is to comprehensively extract the vulnerabilities, in particular,
while assuming examples of attack methods from a list of the threats in “4. Threat and
vulnerability analysis.” In such case, the CWE common vulnerability type list5 is used to
check the completeness.6
With respect to the 21 items including vulnerabilities which should be re-recognized by
developers and users of the MFP, as well as vulnerabilities that became topics of the MFP
in recent years among other vulnerabilities, detailed descriptions of attack methods against
such vulnerabilities are presented. There are also some interviews of the parties related to
MFP vendors, and verification experiments were conducted to ensure the concreteness of
some items described in this report.
2.1
Arrangement of the usage and functions of the MFP
Among the publicly available MFPs provided by five major MFP vendors in Japan, the
usages and functions of the models that are certified under the Japan Information
Technology Security Evaluation and Certification Scheme are specified by using news
sites and published materials.7 The results from the interviews of some MFP vendors and
from verification experiments, which were conducted for confirmation, are sorted out in
Chapter 3.
2.2
Arrangement of the functional blocks
Functional blocks, which are considered to have been used for the MFP, were identified
using publicly available information under the Japan Information Technology Security
Evaluation and Certification Scheme. Functional blocks are organized in the range from
“3.5 MFP system configuration examples” to “3.7 Software inside the MFP.”
2.3
Specifying the data exchanged between functional blocks as assets to be protected
In order to specify the assets to be protected in the usage environment of the MFP, the data
exchanged between functional blocks of hardware as well as main blocks of software are
specified. Among them, the primary assets of the assets handled by the MFP users directly,
and the secondary assets such as security control information, processing data related
secondarily to use of the information system called the MFP, and the state in which a
primary asset is recorded in a specific medium, shall be separated.
Arrangement of the primary assets and secondary assets is carried out in “5. Assets to be
protected by the MFP.”
27001 ISO / IEC - the equivalent Japanese industrial standard is JIS Q 27001:2006
http://www.isms.jipdec.or.jp/doc/JIP-ISMS111-21_2.pdf
5 CWE common vulnerability type list (http://www.ipa.go.jp/security/vuln/CWE.html)
6 The listed vulnerabilities in Chapter 6 and Web interface in Section 7.15 are confirmed to cover the
CWE common vulnerability type list.
7 Public product documentation, such as security target descriptions, catalogs, and white papers
published by MFP vendors.
4
13
Research Report on the Security of MFPs
2.4
2. Research and Analysis Methods
Listing threats and vulnerabilities by each asset
For all of the secondary assets in the state of specific information and medium of the
primary assets, the threats are listed with completeness by applying the common seven
security requirements to them. Vulnerabilities, which are possible causes, are listed as
assumed vulnerability examples while citing instances of how the threats listed take shape
in incidents or attacks.
A list of these threats, attack examples and assumed vulnerabilities are shown in the table
in “6. Vulnerabilities assumed from threats.”
2.5
Detailed explanations of notable vulnerabilities
From the perspective of the vulnerabilities listed, explanations given for vulnerabilities of
the MFP that have been published in the vulnerability database,8 news sites,9 and
international conferences such as Black Hat are studied, with respect to results of some
actual verifications, attack methods and countermeasures to be taken by developers and
users. The scoring for attack potentials on each item is described as a standard for the
feasibility of the illustrated attack methods. For the items with more detailed explanations,
it is confirmed that this report covers the perspectives of publicly known vulnerabilities
that are actually reported, and verifies the vulnerability database as well as CVE as of July
2012.
8
9
CVE (http://cve.mitre.org/cve/index.html)
These are not general news sites, but news sites that are output as results of search using “MFP”
and “vulnerabilities” as keywords in Google.
14
Research Report on the Security of MFPs
3. Usage and Functions of the MFP
3. Usage and Functions of the MFP
3.1
Development history of the MFP
The MFP has been developing over time, while a variety of usages have been found.
Figure 3-1 below shows the development history of the MFP as well as potential usages in
the future from left to right in order.
Originally, MFP was a device that performed an “imaging” process mainly for copying,
but fax is integrated into this, and the transferring function of digitized image data, as well
as the network function, was added later so that its functions have been greatly increased.
Then, more functions, such as “remote sharing,” by which multiple users can share the
MFP via network, and “application extension” to work in cooperation with existing
business systems, were added. This has increased reliability as well as demand for the
security of the MFP.
Figure 3-1 Development history of the MFP
The frame with the dotted black line in the upper-right corner of Figure 3-1 shows
assumed examples of the possibility of function enhancement of the MFP in the future.
This includes a role as a part of the social infrastructure and as an aspect of life kit
functions. “Internet applications” has a way to utilize for more variety of usages by
connecting the MFP with cloud services and services on the Internet. In the office
environment of companies that is the assumption of this report, further development is
expected in the future such as printing in a seamless environment across the offices in each
location of the company.
The research targets of this report are MFPs used in the office environment with common
functions, so functions that are only implemented on the MFP by a few vendors, as well as
future functionality, are not discussed.
15
Research Report on the Security of MFPs
3.2
3. Usage and Functions of the MFP
Security required for the MFP
Figure 3-2 below shows examples of types of security required for the MFP that are
considered to be developing. However, vulnerabilities need to be comprehensively
specified, because the MFP is implemented with a number of functions. Threats and
vulnerabilities in the usage environment of the MFP are identified in the order of the
usages and functions that are initially required for the MFP in this report.
Figure 3-2 Functions and security required for the MFP
“Internet applications” in Figure 3-2 shows applications not only of the functions built into
the MFP, but also of a variety of functions on the Internet and network. One instance is
collaboration with the services that provide indexes for fast searching of sharable
documents stored inside the MFP. There are also other functions, such as extracting
characters from the scanned images for an easy search, and detecting a face from the
photographic images to classify them automatically. Besides, some MFPs have a content
sales function in coordination with settlement functions of digital money and cash, as well
as print functions for certifications such as resident cards in coordination with Basic
Resident Register cards. Not only are they available for the sales and services, but for
insurance application services, for example.
For Internet applications, the leakage of documents that are temporarily stored on the
external storage media in conjunction with cloud services, and the leakage of index
information that is necessary to search documents, are considered indirect threats in the
usage environment of the MFP. Internet applications are not necessarily protected by the
functions or operations of the MFP itself, because it is difficult to generalize, so they are
not listed in the vulnerabilities in Chapter 6, but discussed in Chapter 9.
For “Application extension,” using extended application software developed by third
parties other than MFP vendors, it has a feature to use a variety of functions. For example,
there are linkage functions with external authentication functions and specialized file
16
Research Report on the Security of MFPs
3. Usage and Functions of the MFP
processing. For authentication, some authentication procedures target a single existing
function, but there are also open authentication procedures available in multiple functions.
Such open authentication procedures require measures against threats, such as the
maintenance of session information and the reuse of session information by impersonation,
but the management tends to be too complicated due to its openness. Therefore, measures
such as the adoption of the development framework that provides the integrated
management of the session information are needed.
In “Remote sharing,” a faster network makes high-speed file sharing and function sharing
with remote areas easy to use. Some functions also have the ability to share a printing
function on USB devices in remote areas in addition to file sharing. The network that
supports remote sharing has been used on a regional basis and a national basis using
TCP/IP. Currently, a protocol called IPv4 is mainly used for TCP/IP, but most MFPs
implement a protocol called IPv6, with a wider address range than that of IPv4 and a
strong possibility for more use in the future.
“Imaging” provides basic functions of the MFP, such as image processing for copying,
printing, scanning and faxing, as well as resolution-enhancement and higher speed for
printing and reading. Increases in the number of pixels and color depth, faster print speed,
and faster paper feed are progressing as a unit. In response to this higher-speed
development, security measures such as encryption processing have been becoming
considerably faster.
3.3
Life-cycle in an environment of MFP use
Figure 3-3 below shows the life-cycle from the MFP utilization plan to disposal from the
user’s point of view. Within the general life-cycle of products, this research covers only
the “Introduction,” “Use,” and “After use” phases. The left side of the figure shows work
mainly done by users, and the right side of the figure shows work mostly outsourced to
MFP vendors and professional suppliers.
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Figure 3-3 Life-cycle in the usage environment of the MFP
3.3.1 Plan
“Planning” refers to a stage to consider the purposes and desired effectiveness of using the
MFP by users. The purposes for using the MFP include “the use of the MFP provides an
easy step for document retrieving,” “the safety of document exchanges increases while
reducing the operating procedures,” and “ensuring efficiency and reliability by automating
the recording of necessary work and operations,” etc. Specifying usage and the mechanism
to achieve desired effectiveness according to the goal is to perform “Design.”
In addition, assets to be protected, safety standards to be ensured, and other specific
objectives are also examined in the planning and design stages. Safety standards and
objectives can be specified as security policies, and in general, as the entire information
system of the users including the MFP. Some parts of the security policies may be added
or revised for the usage environment of the MFP.
3.3.2 Introduction
“Introduction” refers to education for MFP users and the installation of MFP device.
Education for MFP users, informs general users about how to handle documents on the
MFP and authentication methods, and provides contact information when users do not
know how to operate, etc. For maintenance personnel and operators, trainings on the
configuration and setup methods for some specific MFP models, monitoring and
verification methods of MFP operations, and how to deal with breakdowns, are provided
as well.
When installing MFP device, such device is properly positioned at specific places, and
installation and initialization of the specific software are performed. Additionally, the
relevant performance should be conducted by installing wiring with the related systems.
3.3.3 Use
In the “Use” phase, work performed mainly on the site where the MFP is used is
categorized as “Operation and monitoring” and “Audit,” while work performed by
maintenance professionals is categorized as “Maintenance.”
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In addition to the work of changing the MFP configuration by administrators, “Operation”
includes the use of MFP by general users. It is assumed that the MFP is operated on the
closed network within the user’s site in general, so the monitoring of the MFP is
considered to be the responsibility of users.
In “Audit,” it is considered whether an appropriate operation has been conducted from the
records of incidents that have occurred during operations and from operating capacity
information, as well as what measures should be taken from the results.
“Maintenance” includes work, such as repairing the main unit of the MFP as well as
adding and replacing parts or software.
3.3.4 After use
“After use” involves the work of “Deletion” and “Disposal.” Users perform “Deletion” of
the data and the configuration information before disposal. “Disposal” includes what
should be done when waste disposers or secondhand goods dealers collect the MFP that is
not used any more.
3.4
MFP from the viewpoint of information systems
Figure 3-4 below shows the usage environment of the MFP from the viewpoint of an
information system. The MFP in the upper right of the figure operates in cooperation with
other services, such as user terminals in the upper left or the accumulation and external
processing in the upper middle of the figure, via the communication system in the middle.
The remote management system on the bottom of Figure 3-4 enables the setup of the MFP
from the other servers or terminals, instead of the console panel of the MFP. The remote
management system also has the functions of authentication and authorization of users, of
the main unit of the MFP, and of the accumulation and external processing services,
respectively.
Figure 3-4 MFP from the viewpoint of an information system
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3.4.1 User terminal
“User terminal” refers to a terminal that provides an input/output interface that uses the
MFP via the network or communication system. MFP users include general users who
print and fax as well as administrators who are responsible for the user management and
configuration of the main unit of the MFP. The meaning of “terminal” is focused on the
point that people conduct operations and displaying.
3.4.2 Accumulation and external processing
“Accumulation and external processing” mainly refers to the machine automation
processing without manual operations by people among the external MFP systems. In the
usage environment of the MFP in particular, providing long-term storage of documents,
temporary storage of job data, and spool processing, is called “accumulation,” whereas a
variety of processing, such as the cooperation of image processing or character extraction
with business systems, and the search processing of documents, are called “external
processing.”
3.4.3 Communication system
“Communication system” refers to the communication systems external to the MFP used
to communicate with external systems. Some of the communication systems are equipped
with Ethernet switches, IP routers and their wiring, as well as wireless LAN access points.
When connecting to the MFP via a USB hub, the USB cable and the USB hub are also
included.
“Communication system” in the usage of the MFP for general office is limited to the
closed networks within a company, such as VPN or LAN in the company using the MFP.
The MFP, user terminals, and accumulation and external processing, are all connected in a
closed network within the company. Sometimes, a closed network within the company is
commonly referred to as “internal network.”
Exceptionally, there are cases for going through networks outside of the company or
Internet, such as remote maintenance interfaces used by maintenance personnel outside of
the company.
3.4.4 Remote management system
“Remote management system” refers to external MFP systems for performing
authentication of users, etc., authority management, monitoring of operations and
functions, and configuration management, etc., when MFP functions are used. Dedicated
software provided by MFP vendors to perform configuration tasks, configuration changes,
and maintenance, as well as browsers used for configuration changes in the MFP are
considered as a part of the remote management system as well. The remote management
system includes remote management, monitoring, and maintenance functions through the
communication system.
3.5
MFP system configuration examples
Figure 3-5 below shows MFP system configuration examples. Blue “MFP” in the middle
of the figure indicates the MFP. The MFP may be connected to portable media such as
USB memory (hereinafter, removable media) and IC card reader for authentication. Some
models may have them built into the main unit of the MFP.
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The lower right corner of the MFP is the “Maintenance terminal” for maintenance
personnel to conduct failure diagnosis of the MFP as well as backup. In the upper-left
corner in the figure, there are a “User terminal” and an “Administrator terminal.” MFP
service is used by installing the MFP driver (printer scanner driver) inside the user
terminal and communicating with the MFP. The administrator terminal is used to remotely
configure the MFP.
The bottom right is a fax function. PSTN fax10 performs an image transmission by an
analog fax modem using the existing telephone network. IP faxing can be performed as a
mail fax through the email servers, and IP fax makes an SMTP connection to the MFP of
the other party directly with IP addresses as well as SIP11 fax to perform the image
transmission of fax using SIP.
Some existing PSTN fax may be used with IP using a device called TA (Terminal Adapter)
that can be converted to SIP or H.323 procedure. There is a benefit of using the TA, such
as reduction of the fax communication fee generated when using the existing PSTN,
because the communication between the PSTN faxes in remote locations can be relayed
via IP network or Internet. TA at the bottom right of Figure 3-5 shows an example of an
IP-PSTN port of the MFP.
Figure 3-5 MFP system configuration examples
“Shared disk and Shared folder” to the left of the MFP are often used to store images
received by fax and images scanned by the MFP. On the left of those, there is “Mail server,”
which is also the destination of the images sent from the MFP when such scanned images
and the received fax images are received by mail. Administrators and users may receive
notifications of processing errors or failures inside the MFP via mail server in some cases.
“Web server” to the left of “Mail server” is used to make use of external images of the
MFP by using a web browser built into the MFP, or is used to collaborate with the business
systems outside of the MFP.
10
11
Abbreviation for Public Switched Telephone Networks
Abbreviation for Session Initiation Protocol (http://www.ietf.org/rfc/rfc3261.txt)
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“Authentication,” of the leftmost yellow square, is the authentication server outside of the
MFP connected to the network, and is a staff authentication server of an in-house system
installed in offices, for example. It may provide a single sign-on function. “Automatic
configuration settings” to the right of “Authentication” has functions, such as
automatically allocating IP addresses, synchronizing to the accurate time, and monitoring
the operation of the MFP in the network including the MFP. “Remote maintenance” in the
upper right corner of the figure is a maintenance service of the MFP by MFP vendors or
maintenance businesses from a remote location. In the remote maintenance, the
monitoring of the lives of the drums and toners as well as the number of papers used is
conducted.
In this example, a server used for spooling the MFP, a monitoring server of the user's site
and a proxy server used by the MFP are not mentioned, but they may be used depending
on the environment of the users.
3.6
Hardware inside the MFP
Figure 3-6 Hardware inside the MFP
The MFP is equipped with multiple functions, such as printing, scanning and networking,
which work together. It is configured by combining several hardware devices, such as
printers, scanners and a substrate, etc.
3.6.1 Hardware inside the MFP - Imaging
The printer is equipped with a paper feed mechanism to retrieve the papers from the paper
tray, a paper sending mechanism from the inside to the outside, and a fixing mechanism
for transferring the images. There is also a finishing mechanism as an additional function
of the print function. The finishing mechanism is called “Finisher,” etc. The finishing
mechanism includes functions of sorting the prints per unit, stapling, and folding them.
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The scanner is a device that highlights the document and reads the reflected light as digital
data. It is equipped with a scanning table such as a glass plate to read one side of a
document at a time. ADF (Auto Document Feeder) is mounted to continuously read
multiple-page stacked documents. The scanning table has a moving scanner module to
read a document placed on the scanning table. Some ADFs are equipped with a different
scanner module other than a scanning table to load information at once when papers are
fed into the scanner. Many MFP models have a scanner module built into the ADF of the
MFP for realizing the fast scanning process.
3.6.2 Hardware inside the MFP – Storage
“Storage” is used for storing documents, temporary job data, and the settings values, etc.,
inside the MFP. Data in storage is rewritable with any manipulation by the users.
3.6.3 Hardware inside the MFP - Unit input/output
“Unit input/output” is a collective name that is uniquely given in this report for the
selected interfaces which communicate face-to-face to the main unit of the MFP. Typically,
there is a USB card interface, which can be mounted on multiple removable media, such
as an SD memory card, a USB memory, or a CF card. Bluetooth and infrared (IrDA)
interfaces are also considered to be connected to the MFP. The parallel interface is an
interface that has been mostly used for older printers, and it used to be equipped with a
terminal that connected to a printer.
“Unit input/output” also includes authentication interfaces, and maintenance/debug
interfaces.
There is an IC card recognition device that authorizes users who operate the MFP console
for authentication, and a biometrics interface.
The maintenance interface has a function to perform failure diagnosis of the MFP at the
time of maintenance of the MFP. The debug interfaces are considered to be no longer
available, but they are interfaces to check, change, or rewrite the state of the software
running on a substrate when developing the MFPs. The debug interfaces control the CPU
at the privileged level, so that it operates without any limitation or authority set inside the
MFP.
3.6.4 Hardware inside the MFP - Remote communication
“Remote communication” is a collective name that is uniquely given in this report for the
selected interfaces which communicate via multiple-stages of communication devices
from the MFP. They are Ethernet, wireless LAN, and PSTN public networks (including
PHS). These communication interfaces enable communications globally through routers,
switches, and exchange devices. While remote communication is considered as a global
interface, unit input/output is considered as a local interface of the MFPs.
3.6.5 Hardware inside the MFP - User interface
The “User interface” of the MFP has a liquid crystal display for displaying the MFP and a
console panel (console, for short) that includes the keyboard. In addition to the MFP with a
console built into the main unit, some models have an external console, and some of them
are large.
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3.6.6 Hardware inside the MFP – Substrate
Figure 3-7 Hardware inside the MFP - Substrate and main interface
Figure 3-7 shows a substrate which is the hardware inside the MFP, and main interface.
Temporary memory (for execution) refers to the volatile memory provided by DRAM
(Dynamic Random Access Memory) etc., when executing the software. The “CPU”
performs the arithmetic processing for executing the software. “Nonvolatile memory” is
used to store software for execution and the set values for execution. “Secure IC (TPM)” is
an IC capable of encryption processing which has a private key to the encryption
processing inside. Secure IC (TPM: Trusted Platform Module) can store the private key
securely without taking the key outside of the secure IC when performing cryptographic
processing.
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3.6.7 Hardware inside the MFP – Connection between modules
Figure 3-8 Hardware inside the MFP - Connection between units or modules
Figure 3-8 above shows the configuration of a connection between a substrate and other
hardware inside the MFP. The figure also indicates how each hardware component is
connected using interfaces from a substrate, but it does not indicate the connection
between hardware components. For example, the Ethernet module is not necessarily
connected to the substrate through the HDD encryption.
IDE/SCSI/SATA/SAS/USB to the left in the figure are among those that are the standard
interfaces for hard disks. IDE (Integrated Drive Electronics) is an inexpensive interface for
personal computers with a long history, but there is a disadvantage in that the connector
tends to be larger due to the number of wires of cable. SCSI (Small Computer System
Interface) has an advantage in that it can be connected to multiple devices such as scanners
and is not limited to hard disks, but it needs as many wires of cable as IDE. While
significantly reducing the number of wires of cable, SATA (Serial Advanced Technology
Attachment) has been provided with higher speeds of transmission than IDE at low cost.
Among hard disk interfaces, SAS (Serial Attached SCSI) is also standardized, but is
generally expensive. A USB is also used as an interface to a hard disk, but it sometimes is
difficult to secure a transfer speed.
HDD encryption in the second row on the left in Figure 3-8 shows the
encryption/decryption functions for the data to be read from/written to the hard disk. Some
“Ethernet” and “Wireless LANs” may be provided on the substrates, but some may be
provided by adding other modules than the substrates. These HDD encryption modules
and Ethernet modules are provided through a PCI (Peripheral Components Interconnect)
bus, a USB bus, or an MFP vendor-specific dedicated interface, because a high-speed data
transfer is needed, and the module itself can be smaller.
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The print unit and scan unit play the core roles of the image processing of the MFP, and
the MFP vendor-specific dedicated interfaces are used as well as high-speed interfaces,
such as the PCI bus, for the usage between the substrates. Image processing functions,
such as deployment of printed images and the processing of the scanned images, may be
included on the side of the print unit and the scan unit.
Modules in the column to the right of the fax unit are slower interfaces. The primary usage
of the fax unit is for monochrome faxing, but the real-time transmission of fax images is
not considered so important for color image transmission. As the fax function is often
treated as an optional function, it may be connected with general-purpose interfaces such
as USB.
“Removable media,” located to the right of the fax unit in the figure, refers to the modules
for removable media, such as USB memory and SD card. Images from a digital camera
can be input to the MFP by inserting or removing the media. “Bluetooth” and “Infrared”
are the wireless interfaces that can input the print images to the MFP, and communicate
with mobile phones or digital cameras at a close range. The difference with the wireless
LAN is that infrared and Bluetooth do not connect with other networks in a wide area, but
can limit the connection only to the surroundings of the MFP. The maximum radius of
Bluetooth is about 10m, and that of infrared is about 10 cm in the absence of things that
block the light.
“Display” and “Keyboard” at the bottom right of the figure refer to a console panel for
display that is equipped with the main unit of the MFP, and a keyboard for operation.
Some models have an independent display device and a keyboard external to the MFP.
“Fee collection” at the top right of the figure is a device that is used by inserting money as
a fee to publicly available MFPs, etc. “IC card authentication, Biometrics” is a module for
authenticating MFP users by using biometric information, such as fingerprints or a
non-contact IC card. IC card authentication and biometrics are connected with the MFP
substrate by USB or RS232C. “Maintenance/analysis/development” is used in order to
examine the cause of the failure of the MFP in detail, and to update some settings as well
as software. Because there is no usage of the development interface for the users in general,
it is either deleted or disabled in the products.
“Fee collection” device is not discussed in this report, because using the MFP in an office
environment is assumed in this report.
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3.7
3. Usage and Functions of the MFP
Software inside the MFP
Figure 3-9 Software inside the MFP
The function blocks of the software, which are executed on the hardware of the MFP, are
organized. Details of the function blocks are as follows:
3.7.1 User interface – Input, retrieve
“Input, retrieve” of the user interface refers to inputting and retrieving of original papers
and prints.
“Network service provision” under the “Communication/network” indicates inputting and
retrieving of job data via networks.
3.7.2 User interface – Operation, display
“Operation, display” of “User interface” refers to the operations and display using the
console panel of the main unit of MFP and the keyboard. Operation guide and marks
indicated by stickers, etc., on the main unit can be included if necessary.
3.7.3 User interface – Documents
“Documents” under the “User interface” refers to the operational materials which explain
how to use the MFP, including user guides and manuals. All the uses of functions operated
on the MFP are described in the materials.
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3.7.4 Application extension – Built-in browser
“Built-in browser” under the “Application extension” refers to the web browsers built into
the MFP. The built-in browser makes a request to the web services or web servers outside
of the MFP in accordance with a prescribed process, and conducts interpretation of the
HTML files received from the web servers as responses, and the execution of JavaScript to
get necessary information. Some may have functions similar to the general web browsers,
and a PDF reader, etc., may be added on.
Examples of the usage of built-in browsers include the operation of other MFPs and a data
request for printing to a web server running on external business systems.
3.7.5 Application extension - DB, search index
“DB” refers to a database used in the MFP. It can be used to manage a large number of
addresses, files stored as shared documents in the boxes in the MFP, and long-range job
data. In some cases, a database with a general-use SQL language interface is used. The use
of the SQL language interface in the MFP requires consideration, because a number of
attacks against the DB and websites using SQL injection in the system have been reported.
“Search index” is an index of information used to search full-texts of the documents stored
in the MFP.
The full-text search is performed based on one or more words throughout a large number
of files at high speed, and the search index is prepared as organized data that indicates the
document files shall be prepared word by word beforehand. Therefore, the search index
contains words that are extracted from a large number of documents and its frequency, as
well as document file names.
As the data of the search index tends to be larger than or equivalent to the size of the
original papers, sharing between multiple users is common. Some documents require
access control, for example, to permit writing and reading only for specific users, so that it
is necessary to pay attention to handling the search index.
3.7.6 Application extension – Extended application execution
“Extended application execution” refers to the function that makes it possible to execute
software, developed by third-party users or developers other than MFP vendors, on the
MFP. In the “Extended application execution,” applications developed in Java12 can be
executed, or specific instructions developed for the MFP can be executed in the browser
inside the MFP.13
MFP vendors distribute a development environment called “SDK (Software Development
Kit)” as an environment for developing extended applications for each MFP. In SDK, in
general, API (Application Programming Interface) is provided with libraries and
12
13
RICOH Developers Challenge
http://www.ricoh.co.jp/javachallenge/outline/
Canon MEAP - “The OS-independent by Java technology”
http://www.canon.us/technology/canon_tech/explanation/meap.html
FujiXerox Apeos IntegrationPlus
http://www.fujixerox.co.jp/solution/dsp/product/integrationplus/index.html
KonicaMinolta OpenAPI
http://en.wikipedia.org/wiki/Konica_Minolta_OpenAPI
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specifications to call services on the MFP and functions of drivers for the MFP, provided
by the specific MFP vendors and specific models, from other software.
By using the SDK, third parties who are not MFP vendors can develop new software,
enhance MFP functions, and operate in cooperation with other systems. Some SDKs
operate with assumptions that software runs outside of the MFP or that software is
installed into the MFP.
3.7.7 Content processing - Image format/compression
To print on paper, the MFP receives the images in a format determined in advance for each
MFP, processes them, and then transcribes them onto paper. Therefore, the MFP has a
function to process data of specific image formats at high speed. It can also directly import
specific image formats, such as JPEG, TIFF, and PDF, or files using image compression
format to decompress them.
3.7.8 Content processing - Character entity format
The MFP in general performs print processing based on the image data bitmapped. There
are cases, however, as in PDF or PostScript, to independently decompress fonts built-in to
the MFP and create print images when character code is received. On this occasion,
support for the corresponding character entity format (character code) is required. In
Japanese, there are multiple character codes, such as JIS, SJIS, EUC, and Unicode. They
are called multi-byte character codes with a length of two or more bytes per character.
3.7.9 Content processing - Font format
Data called “Font” that defines the shape of the character is required to decompress an
image of characters from the character code in the MFP as in PDF or PostScript. The MFP
requires a process corresponding to the specific font format in order to decompress fonts.
PostScript font is provided by MFP vendors for PDF or PostScript.
3.7.10 Content processing - Image identification/recognition
Some MFP models have a function to identify and recognize characters in the images
received via fax or scanned inside the MFP. This function, however, is outside the scope of
this report since it is not built-into the MFP generally.
3.7.11 Content processing - Digital certificate
Some MFP models produce a digital signature using a digital certificate for the digital files
registered in the MFP or images scanned inside the MFP, and provide evidence that may
be needed in business.
There is a method of encryption and digital signature of the content of email called
S/MIME for mail faxing, and a digital certificate can be used.
This is not for processing the documents, but an encryption communication function of the
SSL/TLS provides an authentication of a server/client using a digital certificate, as well as
an exchange of the key.
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3.7.12 Basic software (OS) - Input/output driver, serial, parallel, USB, disk
Generally, basic software (OS) includes control of all hardware and resource management
functions, but the common functions of the MFPs on the market are identified in this
report.
There are general-purpose OS’s that are available for multiple embedded products for
general use, and limited purpose-built OS’s that are dedicated to the specific models or
MFP vendors. A purpose-built OS has less visibility to attackers due to the exclusiveness
of its source code, and the API of the OS is even undisclosed. On the other hand,
general-purpose OS’s are more recognized by attackers, because they are widely
distributed as such systems as Windows, Linux, and VxWorks. However, they provide an
advantage of acquisition of source code if necessary and verify them using a standard API.
It is common for both types of OS to have a possibility of getting involved with a variety
of vulnerabilities in connection with its high functionality and high performance.
Basic software (OS) of the MFP includes an input/output driver. As an external interface of
the MFP, it controls the input and output of serial, parallel, USB, and hard disk.
3.7.13 Basic software (OS) - File system, database
Temporary job data and shared documents to be saved in the long term are stored inside
the MFP. Some configuration information, usage history, and the audit records are stored
either in the file systems or in the database inside the MFP.
3.7.14 Basic software (OS) - Job control
The multiple requests of printing, scanning, faxing, and copying, are directed to the MFP,
and the MFP should process them in order as instructed. Some processing may take more
than a few minutes, and other requests are held in the memory or on the hard disk inside
the MFP in the form of a “Job.”
Job control executes jobs by controlling the receiving jobs, running jobs, holding jobs, and
completing jobs to produce some results.
3.7.15 Basic software (OS) - Time
In cases of the office MFP, the time shall be always synchronized in the system for the log
that records operation history, encryption, authentication servers, and digital certificates. In
the MFP, a component called the real-time clock keeps beating the time even when the
power is off, and it operates at approximately the right time when the power is turned back
on. Sometimes, the time server on the network is used to synchronize the time.
3.7.16 Basic software (OS) - Code, random digits
A process of calculating a hash value as well as processing for encryption is included in
the “Encryption.” When using an encryption in general, “Random digits” play an
important role in order to generate a value hardly expected as an encryption key.
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3.7.17 Management - Setting, configuration
There are many items in the “Setting, configuration” under the operation management of
the MFP, and there can be several hundred or more items. Because each configuration item
depends on the models of the MFP, the configuration per functional block is discussed
without consideration for the details of individual configuration items.
3.7.18 Operation management - Stop, start
There is a power-saving function in the MFP to turn on the power-saving mode
automatically. The power of the fax-installed machine is always turned on, but some
models without fax may be turned off during non-business hours.
3.7.19 Operation management - Activation records
It records the number of copies or prints of the MFP per user, and records the history of
operation management, such as adding or removing software and configuration changes.
3.7.20 Operation management - Maintenance, exchange, repair
Operation management includes functions that correspond to the failure of the MFP, and
which perform replacement of software and hardware components. It contains license
management functions as well.
3.7.21 Operation management - Self-diagnosis
Internal software checks the status of the hardware and software inside the MFP at the
time of MFP failure, and reports defects or failure locations.
3.7.22 Authentication/approval/billing - Authentication, user, administrator
MFP authenticates users and administrators. Maintenance personnel are authenticated as
well.
3.7.23 Authentication/approval/billing - Limitation/permission
Usage limitation and permission imposed by the MFP to all users and user groups.
3.7.24 Authentication/approval/billing - Counting/billing
Summary value of the number of times services are used, and the number of papers used
for printing, copying, or scanning in a specific MFP. It is counted per MFP, in which
maintenance businesses can use it as rationale to charge based upon its uses.
3.7.25 Authentication/approval/billing - Audit records
When using the security functions of the MFP, in particular, processing using a security
function, or its success or failure from the results of the security processing, etc., is
recorded. It can be referred to or summarized at the time of the regular audit of the
operations regarding the security functions of the MFP.
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3.7.26 Communication/network - Network service provision
The MFP stands by for requests from the network to provide services to the user terminals
and other systems. When a request arrives from the external user terminal or another
system, the MFP responds by performing some processing for this request. Such responses,
processing, and responding to the other systems, are referred to as network services.
Because network services are provided by the server running on the MFP, they are also
referred to as server functions. The server functions of the MFP include the SMB server
and HTTP server that provide shared service functions of the MFP, the FTP server that
provides file sharing services, and the SMTP server that provides transfer and delivery of
the scanned or faxed image data.
In addition, there are some network service functions available for maintenance and
management inside the MFP. For administration usage, the SNMP server responds and
changes the running status inside the MFP.
3.7.27 Communication/network - Remote management/control
It is a function that allows administrators to configure the settings and perform
configuration management of the MFP remotely. Maintenance pages or management pages
provided on the web server in the MFP are used by opening from the administrator
terminal.
3.7.28 Communication/network - Communications control
It is a function that allows control of communications over an IP network and procedural
control of receiving and sending of faxes. IP network rather controls Ethernet and
IPv4/IPv6 in comparison to “Network service.”
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4. Data Flow when Using the MFP
4. Data Flow when Using the MFP
The data flow when using the MFP is specified as the following configuration diagram.
Data is categorized as content data such as documents and images, and control data such
as instructions and controls. Content data is indicated by solid lines, and control data by
dotted lines in the diagrams.
Since it is a common process to record all the operations regarding activation records, only
data flow for reading is identified for the writing processing of activation records:
Figure 4-1 Configuration diagram of data flow when using the MFP
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4.1
4. Data Flow when Using the MFP
Printing
Figure 4-2 Data flow for printing instructions such as how to print and the images for
printing are sent to the MFP from the user terminal. The print reception function within the
communication and network module accepts the connection on the MFP. Upon receipt of
the connection, a protected communications path is established, and it saves the job
accepted in the file system after the authentication of users. For authentication, either the
authentication data inside the MFP or the external authentication server of the remote
management system is used.
After informing the job control of the stored job data, the job control sends a print
instruction to the imaging unit while making adjustments with the other jobs, and prints
them out.
When the MFP creates the session information of the user terminal after the authentication
of the user terminal, the session information of the user terminal shall be deleted upon
receiving the job:
Figure 4-2 Data flow for printing
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4.2
4. Data Flow when Using the MFP
Load distribution printing
Figure 4-3 below shows the data flow for load distribution printing. The figure shows the
data flow from immediately after receiving the job data.
The job control reviews the configuration management information from the instructions
included in the job data, and specifies the MFP to give instruction for printing among
external MFPs. The job control gives printing instructions to the print client function of
the browser in the application extension with new instruction data, such as the number of
copies and address of the client that have been specified.
The print client function establishes a protected communications path with another MFP
using a communication and network function. At this time, it uses certificate, password,
secure IC, and time inside the MFP. After the protected communications path has been
established, the print client forwards the stored job data with the specified number of
copies to the other MFP.
Figure 4-3 Data flow for load distribution printing
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4.3
4. Data Flow when Using the MFP
Scanning to X, faxing
Figure 4-4 below is a diagram showing the data flow for “scanning to X” to deliver scan
results to something. “X” here refers to files (storage on the MFP), FTP, and email, etc.,
which are destinations and delivery methods of the scan results. Faxing is also included.
In front of the MFP, a user gives a job instruction to the MFP using the console. Then, the
user scans from the console and gives an instruction as to where to deliver the scan results.
If authentication is required to use the scanner, the user interface uses either the console or
the IC card authentication device and the biometrics device, which is connected to the
serial interface of the MFP, to authenticate as a user.
The user specifies the destination and the scanning method. The destination can be
selected from the address book of the MFP. In some cases, shared address book on the
remote management server may be used via remote communication. The user puts the
original paper on the scanner table by this time.
As specified above, the identification information of the user, the destination, and the scan
method, are all delivered to the job control as an instruction. The job control provides a
control instruction to the imaging, and scan processing is performed in the scanning unit.
As the result of the scan processing, the created file is passed from the imaging to the
storage.
Figure 4-4 Scanning to X, faxing data flow
The file is delivered to the specified destination from the storage in accordance with an
instruction given by the job control. The following is a list of the destinations:
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Research Report on the Security of MFPs
1)
2)
3)
4)
4. Data Flow when Using the MFP
Delivery to the other MFP and the fax: upper left in the figure
Server-delivery to the accumulation and external processing: the second from the upper left
in the figure
Server-delivery to the user terminal: the third from the upper left in the figure
Delivery to the removable media: upper right in the figure
Among the above-mentioned destinations except for the removable media, mutual
authentication, use of certificates, ID, and password, is conducted in order to establish a
communications path protected by using secure IC and time.
Among the above-mentioned destinations, the accumulation and external processing may
mostly require some sort of authentication processing. In such cases, either the
authentication data inside the MFP or the external authentication server of the remote
management system can be used.
The processing is completed when the delivery is completed for all the specified
destinations.
The MFP automatically deletes the session information that was created for the “certificate,
ID, password” when logout is executed by the user after the specified job is completed, or
when a certain time has passed without any operations on the MFP.
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4.4
4. Data Flow when Using the MFP
Receiving fax
Figure 4-5 below shows the data flow for receiving fax. This flow refers to a procedure
from the point of receiving a fax to the point where the information is stored in the storage.
The authentication printing with a user authentication is specified in the printing
procedure.
Either the original papers are read or fax images are sent to another MFP or fax from a
computer at the “other MFP, fax” on the top left of the figure, and then from the “other
MFP, fax,” the fax images are received using the fax reception function of the
“communication and network.” The fax reception function includes PSTN fax, mail fax,
and the SIP fax. In case of mail fax, certificates, secure IC/TPM, and time, being used to
establish a protected communications path. In case of SIP fax, it does not dynamically
establish a protected communications path in general, but ensures security by isolating or
closing the “communication system.”
Received fax images are then stored in the storage, and the reception result is passed on to
the job control. The job control verifies the box distribution conditions by the fax numbers
or the destination numbers, and specifies new destinations either to deliver to the
confidential boxes or servers, or to print on the paper.
The print processing after this is the same as the data flow in “Printing,” and the
processing other than printing after this is the same as the data flow in “Scanning to X,”
after storing the images in the storage.
Figure 4-5 Data flow for receiving fax
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4.5
4. Data Flow when Using the MFP
Copying
Figure 4-6 below is the data flow for copying. A user gives a copying instruction from the
console. A user authentication is performed as necessary. Either the authentication data
inside the MFP or the external authentication server of the remote management system is
used for authentication using password, IC card, or biometrics. When performing a user
authentication with the authentication server external to the MFP, the authentication
request for the user who wants to copy shall be made via “communication and network” to
the authentication server on the “remote management system.”
The user specifies the processing condition for copying using the console. When
specifying settings values established beforehand or load distribution of the printing, the
information that users or administrators have set up among the settings configuration
information shall be used as a reference.
By this time, the user has placed the original papers on the scanner table or ADF.
When an instruction for copying by the user is given, the instruction is forwarded to the
job control, and the copying will begin. The job control sends the instruction for copying
to the imaging. The original papers are scanned and stored in the storage. Stored images
then are forwarded to the printer to print. Images can be stored by creating files on the
hard disk or in memory (temporary memory, DRAM).
User logs out from the console upon completion of the specified job, or the MFP
automatically logs out after a certain time has passed without any operation, and the
session information in the “certificate, ID, password” of the MFP is deleted.
Figure 4-6 Data flow for copying
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4.6
4. Data Flow when Using the MFP
Setting the configuration management information and acquisition (console)
Figure 4-7 below shows the data flow when setting the configuration management
information and acquisition of the MFP. The configuration management information of the
main unit of the MFP includes “certificate, ID, password,” and the operations of “secure
IC/TPM” as well as changes to “time.” The procedure for giving instructions from the
MFP console is shown in this figure.
MFP administrators give instructions for changing the configuration management
information from the console. Therefore, an authentication procedure for administrators
shall be performed. The user interface gives an instruction to the “authentication/
approval/billing” for authentication processing for administrators. IC card and biometrics
shall be performed as necessary. In some cases, IC card and biometrics may require
authentication by the authentication server in the “remote management system.”
When an administrator authentication is acquired, the setup menu of the configuration
management information is displayed on the user interface, and the change, overwriting,
addition, and deletion of the contents of “configuration management information,”
“certificate, ID, password,” “secure IC/TPM,” and “time,” are displayed and retrieved. For
secure IC/TPM, important and confidential information, such as private key, cannot be
retrieved, but the names and identification names of the private key are displayed.
Administrators perform the logout procedure upon completion of the job, and the session
information created in the “certificate, ID, password” of the MFP is deleted.
Administrators do not operate software or licensing, since maintenance personnel change
them.
Figure 4-7 Data flow for setting the configuration management information and acquisition
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4.7
4. Data Flow when Using the MFP
Setting the configuration management information and acquisition via remote
communication
Figure 4-8 below shows the data flow when setting the configuration management
information and acquisition of the MFP via remote communication.
Administrators establish a communications path protected by SSL or SSH in the
management servers of “communication and network” of the MFP from administrator
terminals in the remote management system, and then log in. “Certificate, ID, password”
is used for establishing a protected communications path, and for some cases, “secure
IC/TPM” and “time” are additionally used. Then, an authentication of administrators who
have a connection request from a distance shall be performed from the MFP to the
authentication server of the remote management system.
After a protected communications path is established between the MFP and the
administrator terminal, administrators can change multiple data inside the MFP by
manipulating the setup page or a command line provided by the user interface upon
completion of the authentication of administrators. For the “configuration management
information,” settings values are added, changed, or deleted. The “certificate, ID,
password” are also added, changed or deleted. For the “Secure IC/TPM,” private key and
its attribute information are added or deleted. For the “time,” it is only changed. Common
operations include reading of the data or values, although the private key of the “secure
IC/TPM” cannot be read.
Administrators perform the logout procedure upon completion of the job, and the session
information created in the “certificate, ID, password” of the MFP is deleted.
Administrators do not operate software or licensing, since maintenance personnel change
them.
Figure 4-8 Data flow for setting the configuration management information and
acquisition via remote communication
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4.8
4. Data Flow when Using the MFP
Maintenance, parts replacement, billing, and diagnosis
Figure 4-9 below shows the data flow for maintenance, parts replacement, billing, and
diagnosis.
Maintenance personnel of the MFP perform an authentication for maintenance personnel
using the console. An authentication procedure outside of the MFP is omitted because it is
the same as other data flows. It shows only the data flow of the authentication for
maintenance personnel carried out inside the MFP. Maintenance personnel perform the
authentication by entering ID and password from the keyboard, using the console of the
MFP. For some cases, the maintenance terminal is connected to the maintenance interface
to operate from the command line or simple menu on the maintenance terminal. For the
maintenance interface, its existence is sometimes unknown, or even if it exists, it may not
require authentication.
After the authentication for maintenance personnel is completed, the menu for the
maintenance personnel is displayed to select necessary processing from the console.
A diagnostic process is performed usually at times of maintenance work, such as
inspection, and parts replacement. During the diagnostic process, individual diagnostic
functions of hardware in the figure are performed, and results are retrieved, and there is
also a consistency inspection for data and files. The diagnostic functions inside the MFP
are described in the operation manual for maintenance. Although it is not confirmed
because it is not open to the public, it is believed that diagnosable items and targets vary
depending on the models and MFP vendors.
Maintenance personnel perform the logout from the console upon completion of the job,
and the session information created in the “certificate, ID, password” of the MFP is
deleted.
Figure 4-9 Data flow for maintenance, parts replacement, billing, and diagnosis
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5. Assets to be protected by the MFP
5. Assets to be protected by the MFP
5.1
Primary assets in an environment of MFP use
Figure 5-1 Data flow when using MFP
As seen from users, the direct purpose of using the MFP is the storage and distribution of
documents. When users perform the storage and distribution of documents, information
assets to be protected directly are positioned as “primary assets.” Figure 5-1 above shows
the concept of the MFP processing addresses and documents, which are the primary assets.
Documents are the information to be distributed and saved. Addresses are the information
that represents the destinations to distribute to.
Primary assets are insubstantial because they are information assets. Substantial
information assets vary case by case in concrete terms. In this manner, when the MFP is
used as one of the information systems, concrete information assets that are necessary to
protect the primary assets are positioned as “secondary assets.” For example, documents in
a paper medium mean original papers or prints. Data describing the digitized images and
image contents on the pages is handled as bit strings in memory and files called job data
on the MFP. Addresses and the destination addresses are stored as part of the control
instructions. Information for authentication and security is also considered a secondary
asset that is necessary to protect the primary assets.
Primary assets and secondary assets are defined as “protected assets” in Chapter 7 and
subsequent chapters.
5.2
Secondary assets as targets to be protected to use the MFP
Table 5-1 below shows secondary assets associated with the usage environment of the
MFP. They are divided into four categories.
“Main unit of the MFP” refers to devices and software inside the MFP. Removable media
such as USB memory and SD card are not in the main unit of the MFP, but are categorized
as the “Main unit of the MFP” because it is used closely with the MFP. The MFP can be
operated with these devices and software together.
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5. Assets to be protected by the MFP
“Run-time data” refers to information assets to be exchanged during the copying and
printing processes.
“Other systems” refers to external hosts and devices that provide services such as
management and authentication from the outside of the MFP for the MFP to be operated.
Because the vulnerability of the main unit of the MFP is the major subject in this research,
details of the other systems are not studied, but only the external interfaces of other
systems are focused on and analyzed.
“Activation results information” refers to original papers, prints, files, and records
obtained after processing.
Table 5-1 Secondary assets as targets to be protected to use the MFP
Management/configuration
information
The next chapter describes detailed analysis of threats to these secondary assets. An
overview of each secondary asset and main points that are required from security
perspectives, are summarized as a reference as follows:
5.3
Main unit of the MFP
5.3.1 Main unit (Hardware)
It refers to the main device of the MFP. It is divided into several units as described in “3.6
Hardware inside the MFP.” It is necessary that the correct main device is mounted and is
wired correctly.
5.3.2 Software inside the MFP
The software to operate the MFP. It is mounted by dividing it into several applications and
modules as described in “3.7 Software inside the MFP.”
Software can be added or updated relatively easily, but the correct software is required
inside the MFP. Unauthorized software shall be eliminated.
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5. Assets to be protected by the MFP
5.3.3 Usage license, maintenance license
While users are using the MFP, the user rights of the installed software and the user rights
of maintenance services are issued by MFP vendors, distributors, or maintenance
businesses, as usage license and maintenance license, and are registered on the MFP,
respectively.
There is a variety of terms and conditions of license, but the analysis is performed on the
assumption that the agreement period of license is usually limited, and the license becomes
invalid when the agreement period expires, and the appropriate functions with the license
will be terminated. On the other hand, unscheduled functions or services may operate if a
non-contracted license is registered.
5.3.4 Removable media
It refers to media that can be easily inserted and removed, such as SD memory cards and
USB flash memory. They are not the main unit of the MFP, but are considered as main unit
of the MFP, because they are hardware that can be mounted on the main unit of the MFP.
Some removable media are used to exchange documents by users, and some are used to
perform configuration of the management information and software of the MFP by
maintenance personnel. Although the slots of removable media for users and the slots of
removable media for maintenance personnel are distinguished with different usages, it is
pointed out in the list of threats and vulnerabilities in each case when they have to be
handled differently.
5.4
Run-time data
5.4.1 Job data (spool, image, destination, control)
The job data is a record of image data, such as printing, faxing, copying, and delivery, as
well as control information.
Image data includes digitized images and drawing instructions to reproduce the images of
the display area of prints and original papers.
The control information includes forwarding addresses or destinations, its forwarding
procedure, output destinations of prints, and finish conditions. Finish conditions include
image processing methods such as positioning of the images in prints, number of copies,
and output tray. The processing in accordance with the finish conditions is performed with
a device called a finisher.
The control information may include authentication information. For example, in the case
of a simple authentication printing using only the user ID set on the MFP without using an
authentication server when printing with a user authentication, user IDs that are input from
general user terminals are written in the job data, and the job data may be stored in the
spool of each user on the MFP.
5.4.2 Management/configuration information
Information for setting and registering on the MFP to operate the MFP under the
prescribed conditions, or configuration information stored on the MFP.
For example, there are strings of necessary addresses, path names, numbers, and call
names to cooperate with other systems, while the MFP operates the security functions,
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5. Assets to be protected by the MFP
such as authentication, to provide the prescribed services and to ensure the necessary
security.
The management/configuration information includes information for the MFP to terminate
a certain function, as well as information for usage restrictions of specific functions by
specific users, etc.
5.4.3 Digital certificate, ID, password, session information
It is digital information used to respond to a request for authentication. A digital certificate
has a public key that can validate a private key. The private key is stored in the storage
device, such as secure IC and TPM, to match it with the secure IC to perform the
calculation process during authentication. There is no need for the public key to be kept
confidential. ID and password shall be stored in the non-volatile memory that can be
referred to at the MFP startup, or in the storage inside the MFP, for the matching process
during the authentication process.
The session information is like a token for giving permission per usage session of other
systems or for users who use services. It includes the cookie information of the web
browser, session ID in the URLs, and session ID in the request data in the HTTP POST
requests.
5.4.4 Accurate time
Accurate time is needed to record the history of sending and receiving fax. When
recording the history of operations, the time at that time is also recorded as a record. The
time in the history information of operations shall be accurate to check the records of other
MFPs or other systems.
The time also is the basic information used to perform cryptographic communication,
signature, and verification. It is important for the time of self-signed certificates as well.
For the functions of authentication, approval, and billing, in order to manage the
authenticated time and the duration that can continue the authorization, synchronized
accurate time is needed between the MFP and the authentication server as well as the
server that provides the single sign-on function.
For the software licensing, accurate time is also needed to compare when the license terms
are specified.
5.5
Other systems
5.5.1 Communication system (Switch, DHCP, DNS, NTP)
A server that provides basic information for the network and communication devices to
connect to the other systems that perform remote communication with the main unit of the
MFP.
Communication devices include Ethernet switches, IP routers, and wireless LAN access
points, as well as the wiring for such devices.
Servers that provide basic information about the network include DHCP server, DNS
server, and NTP server. DHCP server performs automatic assignment of IP addresses, as
well as the distribution of IP addresses of router and DNS. The DNS server responds to
search requests for IP addresses among host names, and the search reverse to that. In order
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5. Assets to be protected by the MFP
to synchronize the time between the hosts in the systems and multiple MFPs, the NTP
server responds with the accurate current time.
5.5.2 Remote management system (Authentication, configuration management,
monitoring, maintenance)
Remote management system includes authentication server, configuration management
server, monitoring server, and maintenance terminal, etc. Management applications on the
terminal for administrators used to change settings of the MFP and the web server on the
MFP are part of the remote management system.
The authentication server holds user IDs, passwords, or certificate information to respond
to requests for authentication of users from other hosts including the MFP. The
configuration management server has functions by which administrators can configure
multiple MFPs collectively, etc. The monitoring server has a function to report
abnormalities to administrators or to other systems by reviewing the operating status of
one or more MFPs on a regular basis.
The maintenance terminal performs diagnosis of the MFP and installation of additional
software or licensing when the maintenance of the MFP is required. For such maintenance
work, the maintenance server may perform processing regularly instead of terminals.
5.5.3 General user terminal
A terminal that is used for services for MFP users, such as printing, faxing, scanning, and
retrieving files stored temporarily or for a long time on the MFP. The user terminal
receives faxes by retrieving files from the MFP. Copying is not performed from the user
terminal.
These services for MFP users are never used by maintenance personnel. It is intended to
run as a user terminal when used for testing. The remote management system includes
MFP configuration as well as change of the configuration management information, such
as address book, from the user terminal.
On user terminals, in general, driver software compatible with a specific model of the
MFP is additionally installed. For some driver software, ID and password that are required
to instruct the MFP to print and retrieve scanned images may be set up. When using mail
fax, email address and client certificate of the user may be specified.
5.5.4 Accumulation and external processing (Spooler, shared folder, email, other
business systems)
Being located outside the MFP, it stores and delivers documents. It usually operates as a
server without direct manipulation by people. It is a part of the information system needed
to use the MFP, and includes spool server for jobs, shared folder, mail server, and web
server for business systems. The spool server is a server to temporarily keep a print job on
the MFP, and has an authentication function for users, a distribution function of job data
for the MFP, and the load distribution processing function. Shared folder is a service used
by multiple users to share information on the network disks in which digital files are
stored. The mail server is used to deliver mail fax and email, and consists of a server
sending and receiving emails (SMTP), an email forwarding server (SMTP), and a mailbox
server that provides email messages to the mail box (POP3, IMAP4).
Sometimes, email forwarding servers and mailbox servers may be located outside of the
organizations that use the MFP. MFPs that are the destinations of fax may be located in
other organizations. It is assumed that non-disclosure agreements shall be concluded
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5. Assets to be protected by the MFP
between those organizations to protect the confidentiality exchanged with each other. As
for vulnerabilities of the MFP, it is regarded that vulnerabilities can be found in either
organization, regardless of differences in MFP vendors or MFP models to be used.
5.6
Activation results information
5.6.1 Original papers, prints
Original papers refer to papers to be read when copying or scanning. Prints refer to papers
output by the MFP when copying, printing, or faxing. Contents in the documents are
included.
5.6.2 Shared files in the MFP
Shared files inside the MFP are digital files that are shared in the MFP, including the
images of documents. Some may contain additional control information, such as
destinations, PDF, and job data. Shared files can be viewed and updated by users of the
external terminals of the MFP.
5.6.3 Usage history, audit records
Information on an MFP; for example, which user has done what and when, what request is
made by whom, and what is the result. It may include addresses of the hosts or servers, as
well as authentication ID when processing was performed.
The usage history and audit records are sometimes recorded inside the MFP, and other
times recorded outside the MFP. In general, the access control is set so that the audit
records can be accessed only by administrators. Administrators periodically review audit
records to make sure that there are no security breaches or unauthorized access, and
perform early detection of incidents.
5.6.4 Billing information for MFP use
It includes information about the number of prints and copies made using the MFP. This
information is given to the MFP vendors, etc., automatically or manually by the users, and
it is used for billing.
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6. Vulnerabilities assumed from threats
6. Vulnerabilities assumed from threats
In this chapter, vulnerabilities that are considered to be the causes of the threats in the
usage environment for the MFP are listed, respectively.
6.1
Extractions of the threats
In this chapter, the requirements for information security are categorized into the following
seven types in Figure 6-1 to identify the threats comprehensively.
Figure 6-1 Requirements for information security - Seven types
In this chapter, threats are identified by considering the hypothetical breach of security
against 16 types of secondary assets specified in Chapter 5. These identified threats are
listed in the column, “T. Threat to these secondary assets,” of the table in “6.3 Main unit
(Hardware).” These threats are further illustrated in “M. Examples of attack methods or
incidents that realize these threats” that the feasibility of the attack methods or operation
errors can be expected on a certain level at this point. The vulnerabilities to be considered
as causes of the incidents are listed in “V. vulnerabilities that may cause the examples of
attack methods or incidents.”
The vulnerabilities listed in this chapter do not distinguish between the necessary attack
potentials for attacks and opportunities for attacks. Users should examine the items to
consider in accordance with the security policy of the office where the MFP is used, or
with protected assets handled by the MFP, and make a decision if measures must be taken
or not.
6.2
Those who should take measures against threats
The vulnerabilities listed in this chapter point out those who should take measures against
such threats. They fall into two categories: users and developers. “Users” refers to
companies that purchase and actually use the MFP, which include persons responsible for
the companies, administrators of the information assets and personal information, regular
staff, and temporary staff. On the other hand, “developers” are in a position to incorporate
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6. Vulnerabilities assumed from threats
functional security measures, and “developers” is a collective term for those who have
responsibilities in design, development, functional testing related to security, and delivery,
including management, in MFP vendors, and for those who are maintenance personnel,
etc., of the maintenance side after products are delivered.
Those who should take measures against such threats are checked per vulnerability listed.
If the security function that the developer should implement is not implemented, users will
take measures for vulnerabilities they encounter during operations. On the other hand, the
prevention of defect and termination of the MFP due to its operation by users in a poor
environment may be supported by developers with such functions as a power-off
protection function. However, those who should take measures are selected in a general
sense in this chapter. Items with diagonal lines in the column of those who should take
measures mean items as reactions by the normal functions of the MFP or related
applications, which neither users nor developers can deal with in general.
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6. Vulnerabilities assumed from threats
6.3. Main unit (Hardware)
6.3
Main unit (Hardware)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that
realize these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Assets are wiretapped by direct
connection to the terminals on the
main unit of the MFP or during
wiring. Or, they are wiretapped by
giving the electrical impact on the
main unit of the MFP.
- Bus on the substrates, debug terminals, module bus
terminals, and connection terminals on the main unit of the
MFP, are electrically connected to wiretap the
communication data on the terminals or on the bus.
- Vulnerability that the MFP is in a state of being physically
operable by attackers
Developers

- Vulnerability that connection methods or communication
methods can be easily predicted because the interfaces between
the main unit of the MFP are standard interfaces

- Vulnerability that the communication data on the interfaces
between the units of the main unit of the MFP is not protected

- Immediately after turning on or off the power switch, an
attacker operates the MFP in a privileged state without
authentication, and turns off the protection function of the
MFP by manipulating a specific keyboard or sending a break
signal from a serial port.
- Vulnerability that the function module stops or defects from
the electrical effects

- Vulnerability that the MFP can be operated in a privileged
state if a hardware interrupt is invoked or specified keys are
manipulated during startup after turning on the power or
shutting down the processing after the shutdown command is
given

- An attacker impersonates maintenance personnel to retrieve
the board, including the DRAM, on the substrate of the MFP,
quickly cool it down, and read the data inside the DRAM, so
that a cryptographic key that remains on the DRAM is
leaked.
- Vulnerability that the MFP is in a state of being physically
operable by attackers
- An attacker easily obtains a copy of the software on the
MFP by retrieving the non-volatile memory (FlashROM,
etc.) of the substrate or a HDD.
- Vulnerability that the MFP is in a state of being physically
operable by attackers

- Vulnerability that the cryptographic key on the DRAM is not
protected
- Vulnerability that the stored software on the substrate is not
protected
51



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.3. Main unit (Hardware)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that
realize these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
2. Integrity
- Part or all of the main unit of the
MFP, or wiring, is changed.
3. Availability
- Part or all of the main unit is
stolen or destroyed, and the MFP
is disabled.
- Either power cable or
communication wire is pulled off
or removed, and the MFP is
disabled.
- The MFP does not start because
of the great fluctuation of the
power voltage, or the MFP stops in
the middle of the operations.
4. Authenticity
- Addition or removal of the
devices is unknown because it is
unable to verify whether the
devices mounted on the main unit
of the MFP is correct.
- An attacker changes the HDD of the main unit of the MFP
to obtain unprotected confidential documents, unprotected
address books, unprotected certificates, IDs, and passwords,
in the HDD. [Changing the main unit]
- An attacker installs an additional scanner in the paper
discharge port of the printer or inside the ADF, to obtain
confidential documents and print results by changing with an
additional scanner or flash memory. [Changing the main unit]
- Vulnerability that the MFP is in a state of being physically
operable by attackers (Vulnerability that a third party can
directly access the devices and the terminals in the main unit of
the MFP to add or change devices and parts of the main MFP)
- An attacker rewrites the setup and configuration
management information for the MFP by changing
non-volatile memory on the substrate (EEPROM and
NVRAM, etc.). [Changing devices]
- Vulnerability that the MFP is in a state of being physically
operable by attackers
- The MFP is disabled due to theft or destruction of the
hardware module for encryption or temporary memory for
execution inside the main unit of the MFP.
- Either power cable for the main unit of the MFP or the
scanner is stolen, and the MFP is disabled.
- The operation of the MFP is stopped because of the
electrical load by directly connecting or using
electromagnetic waves, to the power system or signal
switching system of some devices in the main unit of the
MFP.
- An attacker obtains confidential documents and some
addresses by installing a fake HDD unit on the main unit of
the MFP, allowing it to record the job data or the files of
confidential documents.
52


- Vulnerability that the stored data in the storage is not
protected
- Vulnerability that the non-volatile memory can be easily
identified and changed
- Vulnerability that the MFP is in a state of being physically
operable by attackers (Vulnerability that a third party can
directly access the devices and the terminals in the main unit of
the MFP to take out some devices or parts in the MFP)
- Vulnerability that the MFP is in a state of being physically
operable, or in a condition that the unauthorized devices can be
installed nearby, by attackers
Developers




- Vulnerability that the function module stops or defects from
the electrical effects

- Vulnerability in which there is a defect of the hardware
module due to electromagnetic waves from the outside

- Vulnerability in which it cannot be verified whether the
device is correct, such as the HDD being directly connected to
the main MFP or mounted on the main MFP

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.3. Main unit (Hardware)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that
realize these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
Developers
5. Accountability
- Even if part or all of the main
unit is added or removed, the
details and causes cannot be
verified.
- HDD in the main unit of the MFP is changed by an attacker,
but no measures can be taken because when it was done or
who did it is unknown.
- Vulnerability in which the addition or removal of an HDD,
which is directly connected to the main MFP or mounted on the
main unit of the MFP, are not recorded

6. Non-repudiation
- Part or all of the main unit is
added or removed by some
maintenance personnel, but who
specifically did it cannot be
proved.
- HDD in the main unit of the MFP is changed by an attacker,
but no measures can be taken because a fake ID of the
impersonated maintenance personnel is entered into audit
records of the maintenance recorded by the MFP.
- Vulnerability that the names, IDs, passwords, and session
information of other users are reused in the history, allowing
impersonation (unverifiable vulnerability)

- Vulnerability in which arbitrary time or arbitrary user IDs can
be recorded when recording in the history

7. Reliability
- Appropriate processing cannot be
done due to the mistakes of some
devices of the main unit of the
MFP or its wiring, lack of parts, or
insufficient parts.
- Because the wiring of the main MFP is wrong, encryption
module is bypassed, and the data is recorded without
cryptographic processing for the HDD, resulting in the
leakage of confidential documents that remain in the MFP at
the time of its disposal.
- Mistakes of installation location or wiring in the main unit

- Vulnerability in which it cannot be verified or it is not verified
whether the configuration of wiring and devices of the main
unit of the MFP (resource capacity, processing capacity, and
presence of the functions, etc.) is correct or not, when realizing
the specific usages, such as “basic operation" or “security
mode.”

- Temporary memory shortage can cause incomplete delivery
and output for part of the processing, and a problem of the
defect would never be recognized.
- When digital certificates are created on the MFP, a private
key of a digital certificate is saved to an unprotected file on
the hard disk in case the secure IC/TPM is not inside the
MFP. The private key can be leaked to an attacker who has
accessed inside the MFP.
53
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.4. Software inside the MFP
6.4
Software inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Software inside the MFP is
leaked.
- Information in the running
software inside the MFP is leaked.
- Software that is stored on the MFP is wiretapped in the
communication system while it is added or upgraded through
the remote administrative system, resulted in the leakage of
the software.
- An attacker connects to the debug interface inside the MFP,
controls the debug interface without authentication, and
downloads the software by giving instructions to the file
system inside the MFP.
- Arbitrary code is entered by taking advantage of any
vulnerabilities of the software running on the MFP (by
obtaining the privileged mode) to retrieve the software by
giving instructions to the file systems inside the MFP.
Developers
- Vulnerability due to unprotected communication between the
remote administrative systems and the MFP, or that the
protection is imperfect

- Vulnerability that debug interfaces with standard command
systems, such as GDB and JTAG, are easily guessed

- Vulnerability that interfaces, which are used to retrieve MFP,
operate to make the MFP available without authentication
- Vulnerability that arbitrary code is allowed to run on the MFP

- Vulnerability that the control by the privileged mode inside
the MFP (the administrator mode or an authorization-free state
inside the MFP) is taken over.


- An attacker obtains the symbol names, the run-time
addresses, and the machine language instructions of the
software running on the MFP, to develop and sell the attack
code for the MFP, by connecting to the debugger interface of
the MFP that should not originally remain.
- Vulnerability that the debug interface inside the MFP remains
while operating (Vulnerability that the execution state of the
software at the machine language level of the MFP is easily
controlled or taken over)

- An attacker easily obtains a copy of the software on the
MFP by accessing the non-volatile memory (FlashROM, etc.)
of the substrate, and develops and sells the attack code by
easily analyzing the contents and behavior of the software to
identify vulnerabilities.
- Vulnerability that allows the software on the MFP to be
retrieved, and easily analyzed or reverse-engineered

- By the extension application developed by a third party
using the SDK for the MFP, a function to respond to anything
without authentications about the contents of the address
books inside the MFP is exploited and the contents of the
address books are leaked.
- Vulnerability that allows the specific confidential data to be
published without authentication, when the extension
application developed by a third party using the SDK is
performed with the privileged mode inside the MFP

54
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.4. Software inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
2. Integrity
- Some or all of the MFP are
changed or added with
unauthorized software, and
appropriate processing cannot be
performed due to the removal or
deletion of some software (before
and during execution).
- The extension application execution service that should not be used
on the MFP operates, and an attacker executes arbitrary commands to
obtain confidential documents.
- Vulnerability of the security policy leakage or insufficient awareness
on security policy among administrators (in cases of the services that
have not been operated are performed by mistake)
Developers

- Vulnerability that the services inside the MFP that should not be
performed are performed, or that the ports that should not be opened
are open
- Vulnerability of the software inside the MFP that is located where
non-maintenance personnel can rewrite it

- Unauthorized software is injected by tampering with
communication data in the communication systems, when the
software inside the MFP is added or upgraded through the remote
administrative systems.
- An attacker connects to the internal or external debug interfaces
inside the MFP or to the software exchange interfaces, controls
interfaces without authentication, and gives instructions to the
internal file systems or software upgrade functions inside the MFP to
add or upgrade the unauthorized software.
- Vulnerability due to unprotected communication between the remote
administrative systems and the MFP, or that the protection is imperfect

- Vulnerability that the interfaces for adding or rewriting software
inside the MFP operate to make the MFP available without
authentication

- An attacker stopped the audit record function of the MFP by
injecting the unauthorized code to take advantage of the input
vulnerability of the LPR. As a result, the operations continued to run
without history records, being damaged from the attack without
knowing the contents of operation by the attacker since then.
- Vulnerability of the arbitrary code that is allowed to be performed on
the MFP using the data entered

- Vulnerability that the control of the privileged mode inside the MFP is
taken over

- Vulnerability of the specific software functions that are executed on
the MFP while they are bypassed or stopped

- An attacker adds arbitrary code to obtain confidential documents
during the processing of the MFP, because some software inside the
MFP are located where even a third party or users can rewrite it.
- An attacker inserts a hook into the running software so that only the
authentication function in the specific service ports is accepted by the
MFP by taking advantage of the input vulnerability of the MFP. Then,
the attacker can access the MFP to attack by impersonating another
system without authentication, so the business data of the other
systems is leaked.
- An attacker uses the input vulnerability of the MFP and tampers
with the random number generation function of the MFP to return the
same random number all the time. The attacker decrypts the
encrypted SSL/TLS communication that is processed by the
cryptographic processing using the random number generation
function, so passwords and confidential documents of the other
systems are leaked.
55

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.4. Software inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
3. Availability
- Some or all of the software
inside the MFP is deleted or
destroyed, or its operation is
stopped by exploiting the
vulnerabilities of the software, so
the MFP is disabled (before and
during execution).
4. Authenticity
- Changing of the software cannot
be detected because the software
on the MFP or software to be
introduced by downloading or by
memory, cannot be verified its
appropriateness.
5. Accountability
- Even if there is an alteration to
the software on the MFP, its cause
cannot be specified.
- Broken software is injected by tampering with the
communication data in the communication system, when the
software inside the MFP is upgraded through the remote
administrative system.
- An attacker connects to the internal or external debug
interfaces of the MFP, or to the software upgrade interfaces,
controls interfaces without authentication, and gives
instructions to the internal file systems or the software
upgrade function of the MFP to delete the software or rewrite
it with the destroyed software.
- Arbitrary code is entered by taking advantage of any
vulnerabilities of the software running on the MFP (by
obtaining the privileged mode) to delete or rewrite the
software by giving instructions to the file systems inside the
MFP.
- Some extension applications using the SDK consume a large
amount of memory, and the server function of the main unit
of the MFP stops.
- Maintenance personnel mistakenly introduce an older
version of the software that disables some functions.
- A third-party developer, who has no authority to distribute
software as an extension application for the MFP, creates
extension applications that can be installed on the MFP, and
installs into a specific MFP.
- Maintenance personnel mistakenly introduce an older
version of the software and disabled some functions, but
which maintenance personnel has performed via which
interface is not specified.
56
Developers
- Vulnerability due to unprotected communication between the
remote administrative systems and the MFP, or that the
protection is imperfect

- Vulnerability that the interfaces for deleting or rewriting
software inside the MFP operate to make the MFP available
without authentication

- Vulnerability that arbitrary code is allowed to run on the MFP

- Vulnerability that the control of the privileged mode inside the
MFP is taken over

- Vulnerability that some extension applications using the SDK
consume a large amount of resources, such as CPU and
memory, and the functions of the main unit of the MFP or
extension application stop working
- Vulnerability that the software to be added or upgraded to the
MFP cannot be verified as authorized software

- Vulnerability that several maintenance personnel share
maintenance authority, and an attacker cannot be identified

- Vulnerability of user authentication that is not performed
during maintenance

- Vulnerability that the maintenance history is not recorded

- Vulnerability that the required information, such as the time,
user IDs, and operation names of the maintenance, is missing
from the maintenance history


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.4. Software inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
Those who should take
measures
Users
6.Non-repudiation
- Some or all of the software on
the MFP are changed by some
maintenance personnel, but who
specifically did it cannot be
proved.
- There is a record that the specific maintenance personnel
mistakenly introduced an older version of the software, but
he/she denies it, and there is no proof.
7. Reliability
- The MFP is disabled when
software to be upgraded or added
to the MFP is not located in the
right place, wrong code or
unauthorized code is mixed, or
part of software is missing.
- During the remote upgrading procedure of the software by
maintenance personnel, an incomplete form of software is
installed by either injecting a packet that indicates the
communication ends, or injecting software upgrade
completion message to skip the procedure.
- An attacker performs an intrusion test or a fuzzing test
against the specific MFP to discover vulnerabilities, and
attacks the vulnerabilities of the MFP to execute arbitrary
code on the MFP.
- If multiple extension applications using the SDK are
introduced on the MFP, in which multiple large job data are
input, job data is lost due to the race conditions in the
acquisition of the memory.
- A third party of goodwill discovered vulnerabilities and
reported to the MFP vendor, but they neither responded nor
were any actions taken, so the person who reported disclosed
the vulnerabilities. Then, a malicious attacker developed and
sold software for attacks, which causes damages on a large
scale, and the compensation for damage has been claimed.
- An attacker tampers with messages that have the S/MIME
signatures on the fax mail by using the vulnerability that the
MD5 hash function is prone to collision, and the messages
look like having a properly signed digital signature when they
are received.
- MFP cannot connect to the server with a 1024 bit RSA key
of the SSL server certificate with the SSL/TLS protection,
because the key processing of 512 bit length RSA
cryptography is not supported.
- MFP does not support either SSL 3.0 or TLS 1.0.
- Vulnerability of the software
inside the MFP is discovered, and
it is actually exploited.
57
Developers
- Vulnerability that the names, IDs, passwords, and session
information of other users are reused, allowing impersonation
(unverifiable vulnerability)

- Vulnerability that arbitrary time or arbitrary user ID can be
recorded when recording in the history and audit information
- Vulnerability that whether the software to be added or
upgraded is installed correctly cannot be verified

- Vulnerability that the processing of verifying whether the
software is installed correctly can be bypassed or interrupted
- Vulnerability that the planning and implementation of the
software testing on the MFP are not sufficient (including OS,
library and middleware, introduced from outside, or in-house
development)
- Vulnerability created by race conditions in the multiple
extension applications using the SDK

- Artificial vulnerability that there are no plans or measures
available after vulnerabilities of the MFP are found

- Vulnerability that the encryption strength of the encryption and
hash function is less than required




Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.5. Usage license, maintenance license
6.5
Usage license, maintenance license
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Usage license permission
information of the MFP in the user
environment is leaked or exposed.
The usage license fee and the
maintenance license fee used by a
third party are imposed.
2. Integrity
- Part or all of the usage licenses are
changed, which causes either the
software of the MFP of the licensed
users do not operate, or the MFP of
the non-licensed users operates.
3. Availability
- Usage license becomes invalid
changing the time, etc., which
disables the MFP
by
Developers

- On the console on the MFP, an attacker displays the license
information registered with the MFP, takes a note of such
license code string, and uses it by entering as license
information to other MFP.
- Vulnerability that the license information of the MFP for
administrators is viewed by attackers
- An attacker accesses the public folders on the MFP via USB
or networks, retrieves digital files to be licensed, and uses
another MFP by entering and registering.
- Vulnerability that the digital files to be licensed for the
MFP are published by mistake on the MFP

- An attacker retrieves the license information that is registered
in the hard disk of the MFP by scanning the HDD directly. In
case of being encrypted, the cryptographic key is retrieved by
scanning.
- Vulnerability caused by lack of encryption or hashed
protection of the license information in the storage of the
MFP

- Vulnerability that the cryptographic key is not sufficiently
protected when license information is encrypted
- Vulnerability that users do not delete the license
information at the time of disposal

- A used MFP is sold with another user’s license input, and
non-licensed users can use the MFP.
- While the MFP that already obtains the correct license
information entered is operating, it stops operating because the
incorrect license information is re-entered. (operational mistake
or attack)
- While the MFP that already obtains the correct license
information entered is operating, it stops operating one year
before the contract period is over, because the time of the MFP
is set a year earlier. (operational mistake or attack)
58

- Vulnerability of no validity period of the license
information

- Vulnerability that the specific unique information of the
license information, such as model names, serial numbers,
and the names of the software, are not verified
- Vulnerability that invalid license data is input to the
MFP, which disables the MFP

- Vulnerability that the wrong time is set up for the MFP,
which disables the MFP


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.5. Usage license, maintenance license
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
4. Authenticity
- Because it is unknown whether the
usage license is correct, non- licensed
users can use the MFP using the
forged usage licenses.
Developers
- Vulnerability that the license information issued can be
used not only for specific models, but other models

- Vulnerability that the license information issued is not
sufficiently validated inside the MFP, so that the MFP can
be operated with the license information created by a third
party

- Because the license information consists of several digits, it is
identified by trial and error by adding the numbers one at a time
to find out the license information that can be registered to
exploit it.
- Vulnerability that the character string that should be input
to the MFP as a license for the MFP, is easily guessed, or
created by characters in order

- A used MFP with the license information of another company
is sold, because the changing of such license information is not
recorded.
- Vulnerability that the history of changing license is not
recorded

- Vulnerability that the history logs of the operation for
changing license do not include enough information (date,
user IDs, access tracks, contents of operations, and results).

- An attacker, such as a secondhand goods dealer or reseller,
inputs the license information of another company, or inputs
forged license information, in order to use the MFP.
5. Accountability
- Even if the usage license is invalid
or forged, its cause cannot be
specified.
6. Non-repudiation
- Deletion or changing of usage
license/maintenance license is
conducted by maintenance personnel,
but who specifically did it cannot be
proved.
- Since the license information changing is recorded when it is
done within the organization, either the user ID is rewritten, or
the service is terminated by inputting a license that causes the
MFP not to operate, by adding the record which indicates
operations by other users.
- Vulnerability that the record of the operation for changing
license, in which the user IDs are recorded, can be
tampered by a third party [vulnerability that logs can be
tampered]

7. Reliability
- Depending on the specific license
data or specific environment
conditions, it is not determined either
invalid license data to be valid, or
valid license data to be valid.
- An attacker creates license information that causes defect of
the validation function for the license information, and inputs it
into the MFP, and then non-licensed users can use the MFP, or
the attacker can implement arbitrary code.
- Vulnerability that the license validation function is
bypassed because of the termination of the license
validation function, if there is an unexpected value in the
license information

- Vulnerability of the license parameters that causes a
buffer overflow

59
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.6. Removable media (for users, for administrators)
6.6
Removable media (for users, for administrators)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Information that has been recorded
without protection to the removable
media is leaked by the theft of the
removable media.
- The information that is transferred
at the connection point of the slots
and the media in the slots of
removable media is wiretapped.

- An attacker removes to obtain the media that is left in the slot
of removable media. Or, a different user collects it by mistake,
which causes the leakage of confidential documents.
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators
- SD card with backed up management/configuration
information, including passwords on the MFP, is removed by a
person other than administrators because they forgot to remove
it, and confidential documents are copied and leaked.
- Vulnerability that the removal of the removable media
cannot be easily detected visually or aurally

- Vulnerability that the secondary assets, such as
management/configuration information or confidential
documents that were recorded on the removable media,
are not protected by encryption, etc.
- Vulnerability that digital files in the removable media
have been encrypted, but the cryptographic key is easily
guessed or is one of the common character strings of the
medium

- Digital files in the removable media have been encrypted, but
confidential documents are leaked to attackers because the
cryptographic key is one of the common character strings of the
medium.
- An attacker obtains the removable media that is left in the
MFP, and obtains confidential documents remained on the
removable media by using a default common password that is
used in the encryption function of the removable media.
- A probe is mounted on the device of the slot side or contact
point between the media and the slot, and is sent from the
wiretapping device attached to it, and confidential documents
or management/configuration information, including
passwords, are leaked to an attacker.
2. Integrity
- Unprotected information in the
removable media is tampered.
Developers
- After the media is inserted into the slot of the removable
media, an attacker rewrites the original confidential documents
in the media, which have no other copies, by removing the
removable media that is left in the slot.
- Vulnerability that the MFP is physically operable by
attackers
- Vulnerability that transfer data between the media slot
and the removable media is not encrypted or is
insufficiently protected
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators
- Vulnerability that there are no functions to protect the
document data in a removable media
60





Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.6. Removable media (for users, for administrators)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- Unprotected information in the
removable media is tampered.
- After the media is inserted into the slot of the removable media, an
attacker rewrites the configuration information in the media in order to
input it into the other MFP by removing the removable media that is
left in the slot, and then the attacker inputs it into twenty other MFPs.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
Developers

- Vulnerability of the configuration information read without
authorization

- Vulnerability that there are no functions to protect the document
data in a removable media

- Digital files in the removable media were encrypted, but an attacker
rewrote the configuration information because the cryptographic key
was one of the common character strings on the medium.
- Vulnerability that digital files in the removable media have been
encrypted, but the cryptographic key is easily guessed or is one of
the common character strings of the medium

- An interventional device is inserted into the device of the slot side or
contact point between the media and the slot, and confidential
documents and management/configuration information are rewritten.
- Vulnerability that the MFP is physically operable by attackers

- After the removable media is left with the original data saved on it, it
was collected by an attacker or somebody else, which disables the use
of the original data.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- Vulnerability that transfer data between the media slot and the
removable media is not encrypted or is insufficiently protected.
3. Availability
- The slot of the removable media is destroyed to disable the removable
media.
- Vulnerability that the MFP is physically operable by attackers
4. Authenticity
- Whether the specific removable media is
approved by administrators of the
organization cannot be confirmed.
- An attacker prepares an SD card to create defects inside the MFP, and
intrudes the MFP, causing the leakage of confidential documents.
- Vulnerability that the removable media has neither
identification functions nor authentication functions

5. Accountability

- The removable media is either stolen or
destroyed to block the use of reading and
writing, which disables the removable
media.
- Users cannot be identified from the
read/write history of the specific
removable media.
- Large quantities of confidential documents are transferred from inside
the MFP to the removable media, which may be leaked to an attacker,
but which user performed cannot be identified.
- Vulnerability that the usage history of the operation of the
removable media is not recorded


- Vulnerability that the removal of the removable media cannot
be easily detected visually or aurally
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.7. Job data (Image, destination, control)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
6. Non-repudiation
- There are no grounds to prove the
record of user ID or the time for
users in the read/write history of the
specific removable media.
7. Reliability
- For a removable media that is
attached to the MFP, part of the
directory or the contents of digital
files in the media are not readable, or
the file names are no longer
displayed as the job names.
6.7
Developers
- A large number of photo printings had been performed from
the SD card, but which user performed could not be identified
by the user ID in the record.
- Vulnerability that the user ID is recorded for the
operations, but such user ID can be entered with arbitrary
character strings by users [vulnerability that logs accept
arbitrary user ID]

- Unauthorized configuration information was entered from a
SD card, but which card was entered could not be identified.
- Vulnerability that the user ID is recorded for the
operation, but its record can be tampered by a third party
[vulnerability that logs may be tampered]

- Huge files are stored on the SD card, but when reading them
onto the MFP, other files cannot be read.
- Vulnerability of abnormal end in the middle of the
processing if there is a file larger than a specific size in
the removable media

- If Unicode characters are used for a specific language for the
file names of the SD card, they are not displayed as file names,
but the operation menu goes back to the initial state.
- Vulnerability that arbitrary code is executed if
unexpected characters for file names are written on the
removal media

Job data (Image, destination, control)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Job data that is exchanged inside the
main unit of the MFP, or between the
MFP and other systems, is leaked,
and documents and addresses are also
leaked.
- An attacker interferes in the USB memory port for general
users with another USB hub, and wiretaps the job data to be
entered into the MFP.
62
- Vulnerability that the job data or communications paths
sent/received to/on the interfaces between the units inside
the MFP are either not protected, or the protection is
imperfect
Developers

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.7. Job data (Image, destination, control)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Job data that is exchanged inside the
main unit of the MFP, or between the
MFP and the other systems, is leaked, and
documents and addresses are also leaked.
- Job data that is exchanged by the MFP on one of the following routes
is wiretapped: bus and terminal inside the MFP, between the MFP and
the external USB devices, between the MFP and the external Bluetooth
or infrared communication device, between the MFP and devices that
communicate over IP/AppleTalk/IPX; or
by job transmission routes as follows: IP, TCP, raw9100, LPR, HTTP,
FTP, SMB, IPP, SOAP, WebDAV, SMTP, POP3, IMAP4, SSL/TLS,
IPsec, Ethernet, wireless LAN, USB, Bluetooth, infrared/IrDA,
AppleTalk, IPX, and Parallel Interface.
- Since the mail header of the email fax is not encrypted with S/MIME,
an attacker can collect the senders’ addresses and destination addresses
by wiretapping on the unprotected communications paths with SMTP,
POP3, or IMAP4.
- Job data is obtained by unauthorized persons on the following devices:
HDD inside the MFP, user terminals, accumulation and external
processing servers that spool job data, proxy servers, and removable
media.

- Vulnerability that the secondary assets, such as
management/configuration information or confidential documents
that are recorded on the HDD inside the MFP, are not protected by
encryption, etc.

- An attacker steals the hard disk that was used for the MFP with partial
defects due to a replacement for maintenance, and obtains confidential
documents from the unprotected job data that remains in the hard disk.
- Vulnerability that the job data processed on the other systems is
either not protected, or the protection is imperfect

- By sending a large number of requests to the MFP, an attacker makes
the MFP overloaded to prevent it from overwriting or deleting job data.
Then, the attacker takes out a spool file inside the MFP by using another
vulnerability, which resulted in the leakage of confidential documents.
- Vulnerability of the job data that is neither deleted nor
overwritten at the end of the processing of the job data

- Job data that is exchanged by the MFP on one of the following
unprotected routes is wiretapped: bus and terminal inside the MFP,
between the MFP and the external USB devices, between the MFP and
the external Bluetooth or infrared communication device, between the
MFP and devices that communicate over IP/AppleTalk/IPX.
- Vulnerability that the job data sent/received to/on the interfaces
between the units inside the MFP is either not protected, or the
protection is imperfect.

- Vulnerability that the job data sent/received between an
input/output device and the MFP is either not protected, or the
protection is imperfect.

- An attacker intrudes general user terminals to obtain unprotected job
data that remained inside, causing the leakage of confidential
documents.
2. Integrity
- Job data that is exchanged inside the
main unit of the MFP, or between other
systems, is tampered to cause the leakage
of the document destinations, the names
of the boxes to save, and the addresses are
tampered.

- Vulnerability that the job data or channels sent/received between
the MFP and user terminals, other systems, or remote management
systems, are either not protected, or the protection is imperfect
- Vulnerability that the job data processed on the other systems is
either not protected, or the protection is imperfect
Developers
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.7. Job data (Image, destination, control)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- Job data that is exchanged inside the
main unit of the MFP, or between other
systems, is tampered to cause the leakage
of the document destinations, the names
of the boxes to save, and the addresses are
tampered.
3. Availability
-The transmission and processing of job
data are disabled, and
copying/printing/faxing/delivery functions
of the MFP are no longer available.
- An attacker interferes in the communications paths between the MFP
and other systems to insert box names and destination addresses by
tampering with job data, and confidential documents are leaked to the
attacker by sending the copy of the job data.
The target of interference is one of the following routes of the job
transmission procedure: IP, TCP, raw9100, LPR, HTTP, FTP, SMB, IPP,
SOAP, WebDAV, SMTP, SMTP, POP3, IMAP4, SSL/TLS, IPsec,
Ethernet, wireless LAN, USB, Bluetooth, infrared/IrDA, AppleTalk,
IPX, and Parallel interface.

- Vulnerability that the job data sent/received between remote
communication devices and the MFP is either not protected, or the
protection is imperfect
- Vulnerability that the communication system used for the MFP is
in a state of being physically operable by attackers
Developers

- Using one of the following devices, job data is tampered by persons
with no authorization for the job data: HDD inside the MFP, user
terminals, accumulation and external process servers that spool the job
data, and proxy servers.
- Vulnerability that the job data processed on the other systems is
either not protected, or the protection is imperfect

- It continuously creates job data to the MFP, including unexpected
values in the processing of the MFP, and repeatedly stops the jobs to
find the job data that causes defects and termination (fuzzing).
- Vulnerability resulting in receiving unexpected job data, or
defect in the processing

It causes the processing functions for the following job transmission
process to defect or overloaded that stop the processing: IP, TCP,
raw9100, LPR, HTTP, FTP, SMB, IPP, SOAP, WebDAV, SMTP, SMTP,
POP3, IMAP4, SSL/TLS, IPsec, Ethernet, wireless LAN, USB,
Bluetooth, infrared/IrDA, AppleTalk, IPX, Parallel interface, and
ITU-TT.30.
- An attacker injects a termination or interruption message in each
transmission process (TCP FIN, etc.), or key exchange failure message
to lose the session, against the specific session between specific MFP
and other systems (user terminals, accumulation and external
processing, and remote management), and abnormally terminates the
session.
- Vulnerability that the communication system used for the MFP is
in a state of being physically operable by attackers
- It causes VLAN authentication functions, communication functions,
remote management functions, and the external authentication functions
other than the following job transmission of the MFP, to defect or
overloaded that stop the job transmission: 802.1x, EAP, DHCP, DNS,
NTP, SNMP, SSH, TELNET, LDAP, Kerberos, X.509, and OCSP.
- Vulnerability that cannot restrict the processing demand to its
acceptable capacity
64

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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.7. Job data (Image, destination, control)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
3. Availability
- The transmission and processing of job
data are disabled, and
copying/printing/faxing/delivery functions
of the MFP are no longer available.
4. Authenticity
- Users to input job data or names of the
other systems for some processing
requests cannot be confirmed or verified.
Developers
- The transmission of job data is interrupted by destroying,
disconnecting, or electromagnetically interfering with the
communications paths between the MFP and other systems.
- Vulnerability that the communication system used for the MFP
has the potential for being interfered physically by attackers

- The transmission of job data is interrupted by disconnecting, or
electromagnetically or optically interfering with the wires in the
communications paths between the MFP and input/output devices.
- Vulnerability that the communication system used for the MFP
has the potential for being interfered physically,
electromagnetically, and optically by attackers

- The transmission of job data is interrupted by disconnecting, or
electromagnetically interfered with the wires between the bus inside the
MFP or between units.
- Vulnerability that the MFP is in a state of being physically
operable, or in a condition that the unauthorized devices can be
installed nearby, by attackers

- A non-user prints with the MFP by inputting the job data to the MFP,
using a job data transmission procedure without authentication (LPR or
raw9100, etc.).
- Vulnerability that there is no authentication function for the job
data transmission procedure

- An attacker who impersonates the other MFP inputs job data to a
specific MFP and performs printing by using a fake machine that has the
IP address of the other MFP.
- Vulnerability of connection authentication being not performed
during transmission of job data

- Because the communication of the authentication procedure that is
exchanged with other systems is not protected when the MFP
establishes connections to accept job data, user IDs and passwords are
leaked to an attacker, which allows impersonation.
- Vulnerability of connection authentication communication that is
unprotected during transmission of job data

- If a job data contains the information to identify users, user
identification information in the job data is tampered to make it look as
if another user is outputting the job.
- Vulnerability of connection authentication communication that is
unprotected during transmission of job data

An attacker emails to arbitrary email addresses on the specific MFP to
exploit the MFP as a spam server, by inputting an arbitrary job control
command for the job data to be sent to the MFP.
- Vulnerability that execution permissions, for the job control
command of each job data received by the MFP, are not examined
(per MFP, host, or system, etc.)

- An attacker can attack repeatedly without authentication to find
vulnerabilities and to make the next attack successful, because there is
no authentication procedure when establishing a connection for
accepting job data in the LPR and raw9100 servers running on the MFP.
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.7. Job data (Image, destination, control)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
5. Accountability
- In the course of transfer,
transmission, or disposal of the job
data, the modules, the systems, and
which user gave instructions to each
process, are not identified to
determine the cause of the specific
processing.
6. Non-repudiation 7. Reliability
- Vulnerability that servers operated by other organizations
with different operational policies interfere with the route
of the job data transmission
- Some processes are interrupted and fail when the job data with
the specified multiple destinations are input into the MFP, but
which processes failed and were disposed are unknown.
- Vulnerability that multiple processing results for the job
data, or the exceptional processing results, such as failure
and disposal, are not recorded

- Vulnerability of recording with insufficient information,
such as time, users, and processing details, when
exceptional processing results are recorded
- Vulnerability that the user IDs, passwords, and the
session information of other users can be reused, allowing
impersonation (unverifiable vulnerability)

- Vulnerability of having no information to identify an
attacker, or information can be tampered when the history
and audit information are recorded
- Vulnerability of insufficient implementation on exclusive
control of the job data destinations, or multiplexing control
of the job

- While the attacker or other system is processing the
acceptance, against the MFP performing acceptance processing
of a user job data, an attacker implements exclusive job data or
controls, such as data from outside the job control, or data that
ignores the transfer data length of the TCP RESET and HTTP,
and makes the MFP either save the wrong job data or execute
arbitrary codes.
- Vulnerability of insufficient implementation of parameter
check of the job data

- In the processing while the MFP is making inquiries to other
systems, an attacker gives a heavy load to the other systems
from the specific MFP by giving a large volume of unauthorized
job data, and stops or defects the other systems by making the
specific MFP make unauthorized inquiries.
- Vulnerability of insufficient implementation of parameter
check of the job data

- Vulnerability that cannot limit the processing demand to
its acceptable capacity

- Because anyone can input jobs data in the LPR, when an
attacker stops the MFP services by inputting a large volume of
job data with identification information of arbitrary users to the
specific MFP, there is no information in the job data to identify
the attacker.
- Job data is confused with another
job, and the image data and the
destinations are changed.
- When an attacker continues to send the job for the specific
address to the MFP at the same time during/before/after the job
data transmission to outside the MFP, another job data
destination is replaced, and the attacker receives a copy of the
job data, causing the leakage of confidential documents.
- Job transfer process is exploited and
is used to attack the other systems.

- In the fax transmission process of the mail transfer type, an
attacker changes the job data transmission and injects other fax
images using arbitrary SMTP server in the middle of the
transmission, but which server is used for rewriting is unknown.
- For a specific process in the course
of job data processing, modules,
systems, and which user gave the
instruction are recorded, but cannot
be proved.
- Image data is destroyed, and the
appropriate image is not output.
Developers
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
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.8. Management/configuration information
6.8
Management/configuration information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Important information, such as hosts on
which asset information is concentrated, is
identified by the leakage of configuration
information of the main unit of the MFP,
or the configuration information to
communicate with other systems.
- A maintenance personnel exploits his/her authority to take out the
management/configuration information inside the MFP by copying.
- Vulnerability of insufficient education and inadequate contracts
with maintenance personnel

- An administrator copied the configuration information into the SD
memory, and lost it, so the management/configuration information is
leaked to a third party.
- Vulnerability that the configuration information of the MFP is
saved outside the MFP without any protection

- An attacker exploits the MFP console or administrator terminal, which
are left logged in after an administrator is authenticated with the
administrator mode on the MFP, and retrieves the
management/configuration information by impersonating the
administrator to cause the leakage.
- An attacker creates a key logger to attack the USB cable between the
substrate and the console keyboard, to wiretap the
management/configuration information.
- An attacker attacks vulnerabilities of services running on the MFP, to
execute arbitrary code inside the MFP, and copies the
management/configuration information by using a privileged operation,
causing the leakage of the management/configuration information.
2. Integrity
- In the management/configuration
information, the security functions are
disabled to make it impossible to
configure the prescribed security policy.
Developers
- An attacker exploits the MFP console or administrator terminal, which
are left logged in after an administrator is authenticated with the
administrator mode on the MFP, and changes the configuration
information by impersonating the administrator.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- Vulnerability that the MFP console website or the administrators’
management website on the MFP are not automatically closed
after a few minutes of inactivity

- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- Vulnerability that the job data communicated on the interface
between the units inside the MFP is either not protected, or the
protection is imperfect

- Vulnerability that the MFP is in a state of being physically
operable by attackers
- Vulnerability that the privileged operations are performed by
intruding into the MFP from the external interfaces

67



- Vulnerability that the MFP console website or the administrators’
management website on the MFP are not automatically closed
after a few minutes of inactivity
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- There are so many displayed items that
they easily cause mistakes. Because the
settings values consistency is not verified
between the items of the
management/configuration information, it
is not possible to achieve the target
service conditions.


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.8. Management/configuration information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
2. Integrity
- Administrators introduced the MFP settings to achieve the prescribed
security policy, but the communication data was not protected because
some items among several hundred others were wrong. They continued
to be used, because there was no warning message.
- Vulnerability of difficulty to determine if the MFP configuration
is designed to conform to the specific security policy or go against

- There are so many displayed items that
they easily cause mistakes. Because the
settings values consistency is not verified
between the items of the
management/configuration information, it
is not possible to achieve the target
service conditions.
- An administrator stopped the unnecessary services of the MFP as
instructed in the operation manual, and operated only the services that
are used. However, an attacker discovered the service ports that are not
listed in the operation manual by examining the service ports of the
MFP, and attacks the service ports by performing a vulnerability
research to intrude the MFP.
- Vulnerability of the services, for which the privileged operations
are performed by intruding into the MFP

- Vulnerability that the services inside the MFP that should not be
performed are performed, or that the ports that should not be
opened are open

- An attacker impersonates an administrator to login to the MFP
management console to delete the configuration information.
- Vulnerability due to insufficient authentication strength (e.g.,
administrator passwords are too simple or have not been changed
for a long time, etc.)

- Vulnerability due to a lack of implementation that can maintain
sufficient authentication strength

- The overload, due to a large volume of requests by an attacker, caused
the management console not to be able to open, and all remote controls
were no longer functioning while dozens of MFPs continue to print.
- Vulnerability of the communications control functions not being
properly implemented

- Whether the configuration information
of the main unit of the MFP and other
configuration information used to
communicate with other systems have
correct values are not verified.
- The MFP setups that were supposed to be the same as the other MFPs
were in violation of the company security policy (e.g. HDD encryption
functions were not turned on, or S/MIME use was off.).
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- Because port numbers or addresses of other systems connected to the
MFP are wrong, the services are not provided, or wrong information is
distributed.
- Vulnerability that there is no way to verify port numbers and
addresses set in the MFP, for other systems that the MFP
communicates with

5. Accountability
- The configuration information of the
main unit of the MFP and other
configuration information used to
communicate with other systems are
either destroyed or deleted, so the setting
configuration information registered in
advance is disabled.
4. Authenticity
3. Availability
- In the management/configuration
information, the security functions are
disabled to make it impossible to
configure the prescribed security policy.
- Which user changed or deleted the
configuration information of the main unit
of the MFP and other configuration
information used to communicate with
other systems, cannot be verified in the
history.
- In a few months after the operation, dozens of MFPs were set a little
differently from one after another, but there is no way of knowing which
of the administrators made those setups and when such setups were
performed. No safety measures of configuration management can be
taken.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators (A record for
the operation of management/configuration information)

- The configuration information cannot be
input or upgraded.
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.8. Management/configuration information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
6. Non-repudiation
- Information associated with a user,
who changed or deleted the
configuration information of the main
unit of the MFP and the other
configuration information used to
communicate with other systems, is
recorded, but there are no definite
grounds to prove it.
- When an attacker changes the management/configuration
information by impersonating an administrator, he/she adds the
name of another administrator to leave another user ID in the
operation record in order to disrupt the recorded contents.
- Vulnerability of accepting the rewriting of logs by
administrators, etc.

- Multiple users can login with the same user ID, so which user
had performed an attack is unknown.
- Vulnerability that the same user ID can have multiple,
simultaneous setups

7. Reliability
- Information that was entered as the
management/configuration
information is neither displayed nor
saved properly.
- The administrator password is left blank, but it is left as it was
because there was no warning. Multiple users without
authorization can change the configuration information of the
MFP by impersonating administrators, resulting in the leakage
of confidential documents.
- Vulnerability of the accepted management/configuration
information, which has no way to confirm mistakes, such
as contradicted setups or out of its scope, or which is not
confirmed

- The MFP stops when the configuration information is about to
be changed while multiple MFP processes are converged. Then,
it does not start up, or there is something wrong with behaviors
of some functions after start-ups.
- Vulnerability that the configuration information in the
MFP are replaced with unexpected data after processing or
at the time of interruption of processing, when accepting
the updated processing of management/configuration
information, including software upgrades, and even if the
processing resources are not sufficient, the processing
continues

- The MFP never starts up when it tries to start again, when the
software on the MFP is to be added or upgraded while multiple
MFP processes are converged.
- Vulnerability that the running processing inside the MFP
is interrupted or moved to an abnormal state without
considering the load on the processing running on the MFP,
when the accepted management/configuration information
is processed

- An administrator attempted to change the settings by using the
administrative page on the web server of the MFP, but part of
the security functions could not be activated, because a part of
the settings values hide in the web browser that was being used.
Therefore, confidential documents were wiretapped by an
attacker.
- Vulnerability of the MFP management pages, depending
on the difference in versions or in browsers; some of the
setups, descriptions, the menu, and input values, are not
displayed, displayed incorrectly, or are hard to identify

- Some of the
management/configuration
information entered are neither saved
nor displayed.
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.9. Digital certificate, ID, password, session information
6.9
Digital certificate, ID, password, session information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Private keys of the digital
certificates for the main unit of the
MFP, as well as IDs and passwords of
users or other systems are leaked, and
they are exploited for impersonation
of servers and documents.
- Administrators’ IDs and passwords are wiretapped and leaked
via any of the following routes: on the bus between units,
network/remote communication, input/output units, such as
USB, SD memory, and Bluetooth.
- Vulnerability that the communication data on the
interfaces between the main units of the MFP is not
protected
- An attacker impersonates an administrator to use the MFP
administrator mode, causing the leakage of shared documents in
the MFP to the attacker.
- Vulnerability of the default administrator passwords being
used because the MFP is not set up accurately when being
installed
- An attacker impersonates an administrator to login, and
continuously leaks confidential documents by adding the
attacker’s address to the delivery route of documents.
- An attacker wiretaps the unprotected communications between
the MFP and the business systems, and connects to the business
systems by impersonating an MFP to exploit the passwords,
IDs, and session information, which are obtained by
wiretapping. The information handled by the business systems
is retrieved or rewritten by the attacker.
- Digital certificates, IDs, and passwords that are left inside the
MFP after the disposal of the MFP are leaked to a third party.
- The administrator terminal is hijacked by malware injected by
an attacker, and all of the certificates, IDs, passwords, and
session information inside the MFP are leaked to the attacker.
70
- Vulnerability of the absence of administrator passwords
- Vulnerability that IDs, passwords, and session
information are easily predicted (e.g., using a character
string in the dictionary, enumeration of the same character,
IP address, time, etc., or a bias in the random number
generated)





- Vulnerability that the configuration information,
including IDs, passwords, and session information, is
transferred or saved outside of the MFP without any
protection (the leakage in the communications paths
between other systems, histories of the URLs or paths are
handed over, or there are no authentication procedures to
protect passwords)
- Vulnerability that the configuration information,
including IDs, passwords, and session information, is
transferred or saved outside of the MFP without any
protection (the leakage from the storage, non-volatile
memory, history, or records)
- Vulnerability that digital certificates, IDs, and passwords
are not totally deleted from inside the MFP
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
Developers



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.9. Digital certificate, ID, password, session information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
1.Confidentiality
- Private keys of the digital certificates for
the main unit of the MFP, as well as IDs
and passwords of users or other systems
are leaked, and they are exploited for
impersonation of servers and documents.
- Private keys of the digital certificates inside the MFP are retrieved
from the MFP, and an attacker sends faxes to other companies by
impersonating an MFP to make it look like the other organization has
placed an order.
- Vulnerability that private keys of digital certificates are retrieved
from inside the MFP without permission

- Vulnerability that private keys of the digital certificates are not
stored securely

2. Integrity
- User IDs and passwords are tampered,
and the users cannot use the services
provided by the MFP.
[Digital certificates]
- An attacker impersonates an administrator to login, and replaces the
private key for digital certificates of the main unit of the MFP with the
other private key that is made by the attacker, and continuously wiretaps
the ongoing SSL/TLS communication on the server of the MFP.
- Vulnerability that private keys of the digital certificates are not
stored securely

- An attacker exploits the SQL injection to tamper with the
management/configuration information inside the MFP, so the other
side cannot read the mail fax sent to them, or cannot verify the contents
of the mail fax received from other companies. In some cases, it may
lead to misunderstandings that the mail faxes sent by attackers are
recognized as documents from the other specific company.
- Vulnerability of the authentications that are bypassed at the time
of accessing the management/configuration information

- Vulnerability that there are no functions to verify the credibility
of certificates

[IDs, passwords]
- An attacker impersonates an administrator using the ID and password
of the administrator that is often used, to login to the MFP and change
or delete the ID or password of the user to disable the MFP.
- Vulnerability that IDs, passwords, and session information are
easily predicted (e.g., using a character string in the dictionary,
enumeration of the same character, IP address, time, etc., or a bias
in the random number generated)
- An attacker wiretaps unprotected communications between the
administrator terminal and the MFP, to retrieve the administrator's ID
and password, and impersonates an administrator to create another
administrator ID. Then, the attacker continuously collects documents
and addresses that are exchanged on the MFP.
- Vulnerability that configuration information, including IDs,
passwords, and session information, is transferred or saved outside
of the MFP without any protection (tampering in the
communications paths between other systems, there are no
authentication procedures to protect passwords or selected)

- Vulnerability that all the digital certificates, IDs, and passwords
can be added and changed with all the authority needed, if there is
an administrator’ ID and password available

- Vulnerability that the configuration information, including IDs,
passwords, and session information, is transferred or saved outside
of the MFP without any protection (tampering on the storage, or
tampering in the non-volatile memory)

- Private keys of the digital certificates for
the main unit of the MFP are changed and
tampered, and security functions using the
digital certificates either stop working or
are disabled.
- Digital certificates of their own or of
another company have been tampered, and
documents provided by an impersonated
sender are accepted.
- An attacker retrieves the HDD from the MFP, creates a copy of the
HDD, and retrieves administrator's ID and password by extracting.
71

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.9. Digital certificate, ID, password, session information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- User IDs and passwords are tampered,
and the users cannot use the services
provided by the MFP.
- Private keys of the digital certificates for
the main unit of the MFP are changed and
tampered, and security functions using the
digital certificates either stop working or
are disabled.
- Digital certificates of their own or of
another company have been tampered, and
documents provided by an impersonated
sender are accepted.
3. Availability
- Private keys or digital certificates created
or registered in the MFP are deleted, and
the verification of digital signatures, file
encryption, or server certificates, is no
longer available.
- CA certificates are deleted or tampered,
and the server certificates, signing on the
documents, and the code signing, are not
verified hierarchically.
- Because there are no corresponding CA
certificates in the MFP, the MFP cannot
verify the digital certificates obtained by
users.
- IDs and passwords of users and other
systems are either deleted or tampered,
and the MFP is disabled or other systems
are no longer available from the MFP.
Developers
[Session information]
- If “POP before SMTP Authentication” is established on the MFP, and
if the IP address of the MFP within some minutes after the
authentication on POP3 or IMAP4 impersonates a source IP address,
SMTP mail transmission service can be used without authentication, so
an attacker impersonates an MFP to send mail faxes or spam mails.
- Vulnerability of easily being impersonated, because IP address is
used for session information

- An attacker impersonates as if another user terminal is making a
request to a confidential box being used, and retrieves the contents of
the confidential box by specifying arbitrary session information or
without session information.
- Vulnerability that the authorized session information with valid
authentication has not been checked, or the checks are insufficient,
at the time of a request being made

- An attacker makes a request to the MFP scanner box by using the
session information of the user who logged out, and confidential
documents in the scanner box are leaked.
- Vulnerability of the session information that can be used even
after a user is logged out without being deleted

[Digital certificates]
- An attacker impersonates an administrator, changes the MFP time
setting one year ahead, and disables the main unit of the MFP, email
addresses, and digital certificates for other systems stored in the MFP.
The MFP continues to operate while communications paths and the
contents are left unprotected, and the attacker easily wiretaps on the
network, causing the leakage of documents.
- Vulnerability that the enabled/disabled state of the certificates
inside the MFP is difficult to understand

- Although the host name of the main unit of the MFP was changed, the
server certificates inside the MFP stopped working, because the
certificates inside the MFP were not replaced.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- An attacker destroys secure IC/TPM parts inside the MFP or the data
in the parts by an electromagnetic attack, etc., and stops the security
functions using the MFP server certificates and the MFP client
certificates.
72

- Vulnerability that the enabled/disabled state of the certificates
inside the MFP is difficult to understand

- Vulnerability that whether the MFP operates according to the site
security policy is difficult to understand

- Vulnerability that the MFP is in a state of being physically
operable, or in a condition that the unauthorized devices can be
installed nearby, by attackers

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.9. Digital certificate, ID, password, session information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
3. Availability
- Private keys or digital certificates
created or registered in the MFP are
deleted, and the verification of digital
signatures, file encryption or server
certificates is no longer available.
- CA certificates are deleted or
tampered, and the server certificates,
signing on the documents, and the
code signing, are not verified
hierarchically.
- Because there are no corresponding
CA certificates in the MFP, the MFP
cannot verify the digital certificates
obtained by users.
- IDs and passwords of users and
other systems are either deleted or
tampered, and the MFP is disabled or
other systems are no longer available
from the MFP.
Developers

- The digital certificates for the main unit of the MFP inside an
MFP are intruded due to mistakes of operation or the
vulnerability of communication and network modules, and the
digital certificates for the main unit of the MFP are either
tampered or recreated. Thus, users cannot use the SSL/TLS
server function and the S/MIME protection function.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
(operation mistakes)
- Vulnerability of the services, for which the privileged
operations are performed by intruding into the MFP

[IDs, passwords]
- When the authentication continues to fail repeatedly, it
disables the IDs or passwords for a few minutes to a few hours
or longer, so an attacker continues to cause authentication
failures using the victim’s ID repeatedly to make it disabled.
- Vulnerability of the access permission that an attacker can
attempt authentication repeatedly

- An attacker sets the MFP time one year ahead to disable the
passwords inside the MFP that have an expiration period, and
stops the communication with other systems that do not have
automatic updating functions.
- Vulnerability that the services are no longer available due
to the expiration of passwords

[Session information]
- An attacker sends logout requests of the other authorized users
to the MFP, and makes it log out without the consents of the
users. Then, the attacker makes the MFP conduct the
authentication procedure again to attack for interference or
wiretapping IDs and passwords.
- Vulnerability that the authorized session information can
be deleted by any third party

- An attacker impersonates a user without specifying the secret
value provided by the MFP in the previous operation for the
session of the other authorized user, and the session of the user
is disabled.
73
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.9. Digital certificate, ID, password, session information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
4. Authenticity
- IDs and passwords of the specific
users or other systems cannot be
verified as to whether they are
provided by authorized
administrators.
- The specific digital certificates
cannot be verified as to whether they
are issued by a specific, authentic
certificate authority.
5. Accountability
- Who created and registered the
digital certificates in the MFP cannot
be specified.
- IDs and passwords of users and
other systems cannot be verified in
the changed operational history as to
whether they are configured as new.
Developers

- Because some MFPs mistook some user IDs as other users’
IDs due to mistakes by administrators, some users’ print jobs
were input into spool boxes of other users’ to cause the leakage
of confidential documents to unauthorized personnel.
- Artificial vulnerability that ID and password string could
be assigned to different users by mistake when they are set
up in multiple MFPs
- An MFP is set up to make requests to the external
authentication servers by accepting the ID and password strings
from the MFP users, using the external authentication servers.
By exploiting this, an attacker made requests to the MFP on the
password for a specific ID with brute-force attack, made the
MFP confirm with the authentication server by inquiries, and
exploited the MFP with password cracking.
- Vulnerability that the MFP responds to the user terminals
that do not need to be responded for the authentication
(Incorrect setup for the range of the connection permission
to the MFP, opening up unnecessary service ports)

- Vulnerability that the MFP itself or the authentication
servers respond to the authentication requests without delay
or lock regardless of the consecutive authentication failures
of a specific ID

- An attacker passes fake certificates of Company A to
Company B, and Company B sends a fax addressed to
Company A, which is received by the attacker.
- Vulnerability that the digital certificates have not been
correctly implemented on the MFP (Mistakes of certificate
issuance procedure, expiration, differences in the owner
identifier [DN] strings, improper CAs, insufficient
protection of private keys, no confirmation of the names
[CN], vulnerable cryptographic methods or use of
vulnerable cryptographic keys)

- An attacker impersonates an administrator to login to the MFP,
registers other certificates by rewriting the digital certificates
inside the MFP, and stops the security functions that use
certificates inside the MFP. When and who did this is unknown,
because there is no record.
- An attacker impersonates an administrator to login to the MFP,
and adds an ID for the attacker to use. When and who did this is
unknown, because there is no record.
74
- Vulnerability that the improper CA certificates are mixed
with the certificates issued by the Certification Authority
(CA) inside the MFP (root CA certificates and intermediate
CA certificates)
- Vulnerability of no record of digital certificate requests
created inside the MFP
- Vulnerability that the operational history, for such items
as IDs and passwords that are deleted, added, or changed
inside the MFP, is not recorded



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.9. Digital certificate, ID, password, session information
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
6. Non-repudiation
- For a record of the name of a specific
administrator who registered digital
certificates in the MFP, it cannot be
proved that the administrator actually
performed the specific operation.
7. Reliability
- For IDs and passwords of users or other
systems, the length or type of characters is
neither properly entered, displayed, nor
saved. Sometimes, character strings are
shortened, or are inserted or added when
they are not displayed.
Developers
- An attacker impersonated an administrator and temporarily deleted the
digital certificates of the MFP. The attacker pretended as if another
administrator had operated it by adding fake information to the working
record, or pretended as if another administrator had operated it by
deleting the operation record.
- Vulnerability of accepting the rewriting of logs by administrators,
etc.

- Because IDs and passwords sent by MFP users or other systems to the
MFP were unexpected values, the operations to list the information
inside the MFP were performed; for example, arbitrary code was
executed inside the MFP, or an instruction was injected into another
module inside the MFP.
- Vulnerability of the accepted digital certificates, IDs, passwords,
or session information, which have no way to confirm mistakes,
such as contradicted setups or out of its scope, or which is not
confirmed

- Vulnerability that the software inside the MFP defects if digital
certificates, IDs, passwords, or session information are
sent/received from/by the MFP without memory protection

- During the specific processing or when there is a large amount of load,
the verification of the public key certificates attached to the S/MIME
emails or server certificates received are interrupted and bypassed
specific.
- Vulnerability that the configuration information in the MFP are
replaced with unexpected data after processing or at the time of
interruption of processing, when accepting the updated processing
of digital certificates, IDs, passwords, or session information, and
even if the processing resources are not sufficient, the processing
continues

- If there is a large amount of processing or a specific processing,
SSL/TLS communication cannot be performed correctly, or the correct
S/MIME processing cannot be performed by mail fax.
- Vulnerability that the running processing inside the MFP is
interrupted or moved to an abnormal state without considering the
load on the processing running on the MFP, when digital
certificates, IDs, passwords or session information are processed

- Fake CA certificates (root, middle) or validation authority (OCSP, etc.)
are registered, and server certificates of the fake servers of other
systems are wrongly validated, so information assets are leaked to
attackers by using the fake servers.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- Even if there is a record of a user who
newly registered, changed or deleted the
IDs and passwords of users or other
systems, it cannot be proved because there
are no grounds for it.
- Some digital certificates cannot be
verified, because the corresponding
private keys for the specific digital
certificates are not correctly assigned.
75

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.10. Accurate time
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
7. Reliability
- For IDs and passwords of users or
other systems, the length or type of
characters that is neither properly
entered, displayed, nor saved.
Sometimes, character strings are
shortened, or are inserted or added
when they are not displayed.
- Some digital certificates cannot be
verified, because the corresponding
private keys for the specific digital
certificates are not correctly assigned.
6.10
Developers

- Because there is no function to update a digital certificate that
another user used before, or update a password that is leaked
and needs to be disabled, the former user who used the old
certificate, ID, or password, or an attacker who obtained such
information, intrudes the MFP.
- Vulnerability that there are no functions to update digital
certificates, IDs, and passwords
- Vulnerability that there is no periodical password
updating

- If the same user IDs as privileged users on the external file
sharing servers, are registered with blank passwords using the
MFP console, external file sharing servers can be accessed
without passwords of the privileged users, by just logging in
with blank passwords using the MFP console. Thus,
confidential documents are leaked to unauthorized third parties
or users.
- Vulnerability that the different user names that are used in
the different authentication procedures are associated
incorrectly at the time of user authentication or
authorizations for services

Accurate time
T. Threats to these secondary assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
(There is no confidentiality for the
standard time due to its global
consistency.)
(Even if the offset value that indicates
the discrepancy of seconds in the main
unit of the MFP compared to the world
standard time is leaked, the risk is low,
and there is no direct threat: time zone,
daylight savings time)
- When an attacker makes an inquiry to the built-in web server
of the MFP, the time inside the MFP is obtained without
authentication. When it is found that the time inside the MFP is
significantly deviated, the attacker can wiretap by specifying
the communications path where security functions that depend
on the time are stopped.
76
- Vulnerability that the maintenance of the internal time
inside the MFP is not performed when using security
functions that depend on the time

Developers
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.10. Accurate time
T. Threats to these secondary assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- It becomes difficult to audit and
monitor when the time of history data
deviates significantly.
Developers

3. Availability
- Vulnerability due to insufficient authentication strength
(e.g., administrator passwords are too simple or have not
been changed for a long time, etc.)
- The accurate time is disabled because
of the significant deviation.
- An attacker impersonates an administrator to change the MFP
time setting to a month ahead to stop the communications path
protection function using the SSL/TLS and the content
protection function for email forwarding documents using
S/MIME. The attacker wiretaps and tampers with the
documents on the communications paths.
- The time inside the MFP is
significantly staggered, and most of the
digital certificates inside the MFP are
not available, to perform signature
verifications, decryptions, and
non-repudiation by signature.
- While the license information was being used during the
effective period, an attacker interfered with the NTP
communication and responded to the MFP with the tampered
messages so as not to synchronize the clocks inside the MFP.
As a result, part or all the functions that require license,
including the security functions of the MFP, stopped.
- Vulnerability that the communication destinations of the
NTP (multicast, etc.) are not specified

- The ARP of the NTP server was forged by attackers, and the
MFP performed time synchronization with the time which was
significantly delayed using fake NTP servers.
- Vulnerability that the mutual authentication is not
conducted with the communication destinations of the
NTP

- An attacker had made the MFP time significantly deviated at
the time of the attack, so the time of the attack was not
properly recorded. Although it was recorded, it was deleted
during the periodic processing on the next day, as the record
was out of the storage period, and the records were not left.
- Vulnerability that the time synchronization of the NTP is
not confirmed, or warnings of time synchronization failure
are difficult to understand

- The time response function of the MFP stops when it receives
an unauthorized accurate time zone value by mail fax. Then,
the security functions, operational history records, and the
recording function of audit log stop, or a function of the
software module whose license period is examined stops.
- Vulnerability that the MFP time response function stops
working when an unauthorized accurate time zone value is
received

- The accurate time is no longer
available or displayed.
77

- Vulnerability due to a lack of implementation that can
maintain sufficient authentication strength
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.10. Accurate time
T. Threats to these secondary assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers

4. Authenticity
- Which time source is synchronized with
the time inside the MFP cannot be
confirmed.
- An administrator specified the right host name of the NTP server for
the MFP, but an attacker responded back to the MFP with fake DNS
data to connect to the fake NTP. The MFP displays the name of the
NTP server host that is connected, but the MFP time remains deviated
because the IP address of the NTP server that is connected is unknown,
and it is unknown as to whether it is performing as it was setup.
- Vulnerability that the time synchronization source for the NTP
is neither managed nor displayed

- Vulnerability due to unprotected communication between the
NTP servers and the MFP for the time synchronization, or that the
protection is imperfect

5. Accountability
- The host name of the time source and the
time device names, described in the record
when the time inside the MFP is
synchronized, are not confirmed.
- A part of NTP servers in use on the specific MFP fails to cause
synchronization with the abnormal time, but no measures can be taken,
because which NTP server shall be stopped is unknown due to no
history recorded.
- Vulnerability of insufficient history records, such as the time
synchronization processing of the NTP, or synchronization
sources used are not recorded even if there are records

6. Non-repudiation
- It cannot be proved that the other systems
provided the wrong time to synchronize the
time inside the MFP.
- An attacker impersonated one of the NTP servers that an MFP is
using, and the MFP synchronized the wrong time when the attacker
responded to time synchronization. This record was left on the MFP,
but this MFP did not protect the NTP communication, so there is no
proof that the specific NTP server responded with an incorrect time.
- Vulnerability due to unprotected communication between the
NTP servers and the MFP for the time synchronization, or that the
protection is imperfect

- A history of the time synchronization has been recorded, but it is
disabled for verification, because there is a possibility that the record is
tampered.
- Vulnerability of accepting the rewriting of logs by
administrators, etc.

3. Availability
- Vulnerability that a stop or failure of the real-time clock
hardware is not detected
- The accurate time is no longer available or
displayed.
- Since the time inside the MFP was not correct, web pages on the MFP
that use cookies stopped performing because the session information
was determined to be always invalid.
- Kerberos authentication always failed, because the time inside the
MFP was not correct. Because the single sign-on function of the
centralized authentication servers was not used, the authentication by
password input was performed on the unprotected communications
paths, resulting in the leakage of passwords to attackers.
- The MFP have been used without security functions being operated,
because the time inside the MFP remains as an initial value (1970)
after starting up the MFP while the battery of the real-time clock inside
the MFP runs out. Documents and passwords are wiretapped on the
communications paths.
- Whether the NTP time source is the
specified time source cannot be identified,
and a fake source can be referred.
78
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.10. Accurate time
T. Threats to these secondary assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
7. Reliability
- The start-up time is significantly
deviated.
- The time is synchronized with the
standard time, but the time offset of the
region is not output.
- The time fluctuates without
synchronizing the standard time when
the time passes.
- It is impossible to arrange output
documents in order of time.
Developers
- The dates of job data, emails, and files, sent to other systems,
are significantly deviated because the clock battery in the used
MFP has run out. As a result, since job execution records are
sorted and displayed by dates from the latest, job records
copied and forwarded illegally by an attacker are unnoticed,
because such job records are sorted out as old records.
- Vulnerability that a stop or failure (loss of battery, etc.)
of real-time clock hardware is not detected

- A used MFP has been used without the time settings since its
purchase, but the time is disabled for the history record when
referring to the operation records of other systems, because the
time information of operational history for auditing or
management, and error records, deviate significantly.
- Vulnerability that can be migrated to the operating state
without setting the time at the initial MFP setting

- An administrator set up the time inside the MFP using the
MFP console, but it caused a one year deviation because the
administrator mistook the digit in the year. Therefore, digital
certificates with a correct expiration period were determined as
expired and were not used in the MFP.
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators
- The time inside the MFP is deviated because the time cannot
be synchronized with the time of the specified NTP server.
- Vulnerability of the NTP procedure that cannot be
properly processed

- The MFP time becomes an abnormal value after one year of
operations without turning off the power. The usage right of the
MFP is determined to be invalid in comparison with the license
period of the MFP, resulting in part or all of the MFP functions
no longer being available.
- Vulnerability that the clock inside the MFP generates
several numeric overflows (16 bit signed/unsigned, 32 bit
signed/unsigned, second/ms/us)

- Digital certificates with 30 years validation are created as of
2010, and were installed on the MFP, but the validity of the
digital certificates cannot be verified because the comparison
of the date and time inside the MFP is not properly processed.
- When setting the time zone that is advanced by 5 hours and
30 minutes from the Greenwich Mean Time and the daylight
saving time that is advanced by 1 hour, only an offset of 5
hours and 0 minutes is reflected for the time of fax documents.
- Vulnerability of having a year 2038 problem in the time
processing of the MFP (32 bit overflow)

- Vulnerability that does not support minutes for the time
zone and daylight saving time
- Vulnerability that the MFP does not maintain the
Greenwich Mean Time (GMT)
- Vulnerability of incomplete processing for the time zone
and daylight saving time

79
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators




Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.11. Original papers, prints
6.11
Original papers, prints
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Original papers or prints
containing confidential information
are leaked to a third party.
2. Integrity
- Original papers or prints are either
replaced or changed.
- A third party reads original papers or prints that are left on the
copying table or output tray, or takes out a copy by copying or
scanning.
- Vulnerability that the MFP is in a state of being
physically operable by attackers

- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators


- Vulnerability of unconditional paper outputs by remote
printing or receiving of faxes
3. Availability
- Original papers cannot be read
automatically.
- Prints cannot be output to the
appropriate print tray.
- A third party replaces original papers or prints that are left on
the copying table or output tray, with fake documents.
Developers
- Vulnerability that the MFP is in a state of being
physically operable by attackers

- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- Vulnerability of unconditional paper outputs by remote
printing or receiving of faxes

- About 10 pages were copied simultaneously while Mr. A was
copying a large volume, but part of Mr. A’s prints were mixed
with the others because of the processing errors, due to a large
volume of processing accepted by the network concurrently.
- Vulnerability of a resource shortage due to interruption by
the multi-stage processing or race conditions that cause
errors on execution control of the finisher

- Original papers cannot be automatically read because a foreign
matter that is inserted into the ADF by an attacker.
- Vulnerability that the MFP is in a state of being
physically operable by attackers

- Vulnerability that unauthorized devices are installed
nearby, by attackers

- Vulnerability that the MFP is in a state of being
physically operable by attackers

- An attacker removes a cable to the ADF of the MFP and a
cable to the finisher in order to disable the ADF and the finisher.
- The ADF and the finisher do not work properly due to the
generation source of a strong electromagnetic wave near the
MFP, so they are disabled.
- Papers and toner cartridges that were loaded in the MFP are
stolen, which disables copying/printing/fax reception.
80
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.11. Original papers, prints
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
3. Availability 4. Authenticity
- Original papers cannot be read
automatically.
5. Accountability
- For some scan data and fax data,
the user who input the original
papers cannot be identified.
Developers

- Papers and toner cartridges that were loaded in the MFP are
run out, which disables copying/printing/fax reception.
- Vulnerability of unconditional paper outputs by remote
printing or receiving of faxes
- A third party collects original papers output by the ADF,
causing the leakage of confidential documents.
- Vulnerability that the MFP is in a state of being
physically operable by attackers
- A third party collects the prints in the output tray, causing the
leakage of confidential documents.
- Vulnerability of unconditional paper outputs by remote
printing or receiving of faxes

- A fake order instruction arrives at a company via fax with the
name of the company as a sender, but the individual sender
cannot be identified.
- The user authentication function is not provided when
using the MFP

- Vulnerability that the authentication results of MFP users
are not recorded along with the operational history

- The user authentication function is not provided when
using the MFP

- Vulnerability that the authentication results of MFP users
are not recorded along with the operational history

- Prints cannot be output to the
appropriate print tray.
- Whether original papers are
collected by the authorized users is
unknown.
- Whether prints are collected by the
authorized users is unknown.
- For some prints, the user who
copied cannot be identified.
- A large number of prints are output from an MFP, but the
individual who performed the output cannot be identified.

6. Non-repudiation
- For some scan data and fax data,
the user ID of an individual who
input the original papers is recorded,
but there are no grounds to prove it.
- An attacker scans the fictitious receipts/invoices, stores and
circulates them. However, when it is pointed out after the audit,
the attacker claims that the data is scanned by someone else, and
it cannot be proved.
- Vulnerability of accepting the rewriting of logs by
administrators, etc.

- For some prints, user ID of an
individual who output is recorded,
but there are no grounds to prove it.
- For a large amount of color prints, the individual whose user
ID was in the output record denies the performance and it
cannot be proved.
- Vulnerability of accepting the rewriting of logs by
administrators, etc.

81
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.12. Shared files inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
7. Reliability
- A large volume of original papers and
prints cannot be output in the correct
order.
- Incorrect output and storage are
conducted if the interrupt processing is
performed in multiple stages.
- Prints can neither be printed as images
nor finished as specified: i.e., positioning
and images of the output are different; it
cannot be discharged into the
appropriate tray; prints are not output by
specified number as instructed; collating
does not work; stapler does not work;
punching does not work; it
staples/punches on the wrong spots; and
folding does not work or is wrong.
6.12

- Thousands of pages have begun printing, but image positioning, page
order, or binding of some prints become failure by accepting a large
number of requests from an attacker. They became a waste disposal, and
caused damages due to delay in the specified delivery date.
- Vulnerability that the resources inside the MFP are not sufficient
when the MFP receives a large amount of processing, and the
processing as instructed cannot be performed because part or all of
the job data are destroyed or mixed
- Thousands of pages have begun printing, but the binding of all prints
became failure because of the electromagnetic interference from an
attacker, causing a waste disposal. A large amount of toners and
hundreds of thousands of papers are wasted.
- Vulnerability that unauthorized devices are installed nearby by
attackers

- Piling up of punching wastes, failure of a large volume of printing by
wrong staples for replacement
- Vulnerability that piling up of punching wastes and wrong
staples for replacement are not noticeable (the security policy
leakage or insufficient awareness on security policy among
administrators)
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- Paper jams or several papers were drawn in at the same time in the
middle of a large volume of printing, because several sheets of different
thickness papers were mixed in the paper tray, causing printing failure.
Developers

Shared files inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Files containing confidential
information are leaked to a third party
from the shared folders in the main unit
of the MFP.
- An attacker changes the request argument to find out the path names of
the configuration management files that contain passwords inside the
MFP.
- An attacker tricks the SQL injection to the request argument, and
retrieves confidential files, regardless of any restrictions.
- Confidential files were leaked to a third party, because such
confidential files were in the public folder in the shared folder in the
MFP.
- Confidential files were in the confidential folder, but such
information could be leaked to the wrong authority, because attackers
could get the files with the privileges of general users or guests.
82

- Vulnerability that the names of the undisclosed shared folders
and files can be read due to insufficient examinations of the
requests to the shared folders inside the MFP
- Vulnerability that confidential documents are placed in the public
folder by mistake (Vulnerability of the security policy leakage or
insufficient awareness on security policy among administrators)
- Vulnerability that proper usage authorization has not been
implemented
- Vulnerability that proper users cannot be authorized, and the
allocation processing of proper usage authorization cannot be
performed
Developers



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.12. Shared files inside the MFP
1. Confidentiality
T. Threats to these secondary assets
M. Examples of attack methods or incidents that realize these
threats
V. Vulnerabilities that may cause the examples of attack
methods or incidents
- Files containing confidential
information are leaked to a third party
from the shared folders in the main unit
of the MFP.
- By using a search function for shared folders inside the MFP,
confidential document names can be disclosed to anyone. In some cases,
such documents can be leaked to a third party by downloading them as
they are.
- Vulnerability that undisclosed file names are leaked when a
search is performed

- Vulnerability that allows bypassing of security functions by
opening files through searching

- Confidential information is leaked to unauthorized users by taking
advantage of the absence of authorization when displaying files in
shared folders in the MFP using the console, outputting them to SD
memory, printing them on paper, faxing them, delivering them to
inboxes, delivering them to folders in other systems such as PCs,
delivering them via emails, or sending them to URLs in other systems.
- Vulnerability that allows bypassing of security functions
depending on the types of the output destinations

- An attacker impersonates an administrator to create and obtain
backups including shared folders inside the MFP, which results in the
leakage of confidential documents in shared folders.
- Vulnerability due to insufficient authentication strength (e.g.,
administrator passwords are too simple or have not been changed
for a long time, etc.)
2. Integrity
- Files in the shared folders in the main
unit of the MFP are either replaced or
changed.
Those who should take
measures
Users
Developers

- Vulnerability due to a lack of implementation that can maintain
sufficient authentication strength

- Maintenance personnel collect and bring back defective HDDs when
they replace storage devices. They can retrieve files in the shared folders
which contain confidential documents.
- An attacker uses SQL injection or command injection against a DB
engine inside the MFP to rewrite files.
- Vulnerability caused by a lack of encryption protection of data in
the storage, etc., or the protection is imperfect

- Insufficient examinations of the contents of the requests, such as
folder names, path names, ID numbers, and attributes, etc., in
shared folders in the MFP

- Some data are changed when certain documents are input while
generating requests that create a resource overflow or a race condition
inside the MFP.
- Vulnerability that causes data change due to a resource shortage
or race conditions during the massive processing on the MFP

- An attacker successfully bypasses the authentication procedure, either
by sending an "Authentication completed" message during the
procedure, or by sending a request during the authentication process,
against the authentication procedure of the shared file server in the MFP.
- Vulnerability that allows bypassing of authentication for shared
files inside the MFP

- An attacker wiretaps unprotected communication between
administrator terminals and the shared file servers in the MFP,
impersonates an administrator against the shared file servers by
exploiting the retrieved session information, and changed the shared
files inside the MFP with other files using the administrator privilege.
- Vulnerability due to unprotected communication between the
shared files inside the MFP and other systems

- Due to overload, some or all of the search indexes or databases for
document management are destroyed.
83
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.12. Shared files inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- Files in shared folders in the main
unit of the MFP are either replaced
or changed.
3. Availability
- Services of shared folders in the
main unit of the MFP are disabled,
or it takes a very long time to
respond (for retrieving, writing,
updating, and listing files).
- An attacker impersonates an administrator to retrieve backups,
tampers with them, and rewrites them (restore) to tamper with
the shared files inside the MFP.
- An attacker removes storage parts, rewrites the sector in the
storage parts, and puts them back in the MFP to tamper with the
shared files in the MFP.
- An attacker uses SQL injection or command injection against a
DB engine inside the MFP to delete files inside the MFP or
document information in the DB.
- An attacker sends a large number of requests that fail
authentication for the MFP, and the MFP locks out
authentication for most users for a while.
- A request that generates an infinite loop of processing in the
shared folders in the MFP is injected, and it makes the MFP
responses slow, or causes it to stop.
- The MFP receives a large volume of requests, and the shared
file services in the MFP stop.
- The storage device inside the MFP is either removed or
defects, and it disables all the shared files inside the MFP.
4. Authenticity
- Which user created part or all of
the files in shared folders in the
main unit of the MFP is unknown.
- User attributes are not recorded when the files are created in
the shared files in the MFP, and an attacker can create files of
unknown users any time.
- An attacker sends the specified job files with an unusually long
user ID to the MFP, and the shared file management software
inside the MFP saves the files without recording the user
attribute information.
84
- Vulnerability due to insufficient authentication strength
(e.g., administrator passwords are too simple or have not
been changed for a long time, etc.)
Developers

- Vulnerability due to a lack of implementation that can
maintain sufficient authentication strength
- Vulnerability caused by a lack of encryption protection of
data in the storage, etc., or the protection is imperfect

- Vulnerability that a resource shortage, or stop or delay of
processing, due to insufficient examinations of the requests
to shared folders inside the MFP
- Vulnerability that a function to reject authorized users is
exploited when authentication failure continued by the
requests of attackers

- Vulnerability that services on the shared folders become
unavailable due to the accumulation of a large volume of
requests and processing (pressure from the processing
memory, CPU processing volume, and bus bandwidth;
pressure of disks from temporary files, document files, and
the log files)
- Vulnerability that the MFP is in a state of being
physically operable by attackers



- Vulnerability that the digital signature of the author of the
shared folders inside the MFP is not used

- Vulnerability that user attributes of the shared folders
inside the MFP do not indicate the author of the documents
- Vulnerability that the recording process of the user
identification function and identification information is
bypassed when shared files are created on the MFP

- Vulnerability of the shared folders inside the MFP that the
input value is not examined sufficiently at the time of
storage


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.12. Shared files inside the MFP
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
5. Accountability
- Who created or viewed the
specific files in shared folders of the
main unit of the MFP cannot be
traced back in the history.
- An attacker conducts a directory traversal to view all of the
MFP shared folders, identifies the names and divisions of the
authors who create important documents to conduct more
attacks. Activities of the attacker cannot be detected through
monitoring and auditing by the MFP operators, so attacks
cannot be prevented.
- Vulnerability that the operational history of the shared
files inside the MFP is not recorded

6. Non-repudiation
- The IDs of the users who created,
updated, and viewed the specific
files in shared folders of the main
unit of the MFP were recorded, but
it cannot be proved even if the users
deny such performances.
- An operator confirmed the record of a user viewing a large
number of files, but the viewing record of the user was not
his/hers, because it could be easily tampered or injected.
- Vulnerability of accepting the rewriting of logs by
administrators, etc.

7. Reliability
- Document files that are input, or
part of the contents of the document
files retrieved, are changed with the
other jobs or other files.
- While an attacker is generating requests to create a resource
overflow or a race condition inside the MFP, some data are
changed when specific documents are input.
- Vulnerability of a resource shortage due to a large volume
of processing or processing errors due to a race condition

- Document files that are input
disappear when they are retrieved.
- While an attacker is generating requests to create a resource
overflow or a race condition inside the MFP, the processing of
saving some documents becomes imperfect. It appears that the
documents are saved from general users, but they cannot be
retrieved because they are not saved.
- Vulnerability of a resource shortage due to interruption by
the multi-stage processing or processing errors due to a
race conditions

- An attacker injects a command to specify unauthorized file
attribute values, and generates an overflow in the shared file
management software inside the MFP, to execute arbitrary
commands.
- Vulnerability that arbitrary code is executed due to a lack
of examination of input shared file attribute valuesinside
the MFP (path names, IDs, attribute values, and file data)

- Arbitrary code is executed.
85
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.13. Usage history, audit records
6.13
Usage history, audit records
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- One or more destination addresses,
senders’ numbers, server addresses in the
usage history or audit records are leaked.
Developers
- An attacker tricked the SQL injection to the request argument, and
took out the usage history regardless of any restrictions.
- Vulnerability that the names of the undisclosed shared folders
and files can be read due to insufficient examinations of the
requests to the MFP, and vulnerability that the examination of the
authentication and authorization is bypassed by injecting the
command (command injection)

- The usage history was in the confidential folder, but it was leaked to
the wrong authority, because attackers could get the files using the
privileges of general users or guests.
- Vulnerability that the authentication and authorization of the
users of the usage history and audit records are not properly set up,
or the allocation processing cannot be performed properly

- The usage history is leaked to a third party because the information is
in the public folder in the MFP.
- Vulnerability of the usage history published in the folder that
does not require authorization

- If the usage history is accessed via a search function, it is leaked to a
third party due to unauthorized downloading.
- Vulnerability that allows bypassing of security functions by
opening files through searching

- The usage history is leaked to unauthorized users by taking advantage
of the absence of authorization, when displaying the usage history using
the MFP console, outputting it to SD memory, printing it on paper,
faxing it, delivering it to inboxes, delivering it to folders in other
systems such as PCs, delivering it via emails, or sending it to URLs in
other systems.
- Vulnerability that allows bypassing of security functions
depending on the types of the output destinations

- An attacker impersonates an administrator to create and obtain
backups including the usage history, which results in the leakage of the
usage history.
- Vulnerability due to insufficient authentication strength (e.g.,
administrator passwords are too simple or have not been changed
for a long time, etc.)
- Maintenance personnel collect and bring back defective HDDs when
they replace storage devices. They can retrieve the usage history,
resulted in the leakage.
86

- Vulnerability due to a lack of implementation that can maintain
sufficient authentication strength

- Vulnerability caused by a lack of encryption protection of data in
the storage, etc., or the protection is imperfect

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.13. Usage history, audit records
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- A part of the usage history or audit
records that are recorded are
tampered.
- An attacker tampers with the time, user ID, or processing of
the specific records of the usage history and audit records by
SQL injection or command injection.
- In order to disrupt the usage history, an attacker injected the
records into the usage history record modules inside the MFP as
if the other user had done it.
- An attacker updated the usage history without authentication.
- An attacker updated the usage history by being authenticated
as a general user.
- An attacker tampered with the usage history that was placed in
a writable folder.
- An attacker either sent unauthorized forms of usage history
requests to the MFP, or requested to complete the authentication
before the authentication was completed. The MFP updated the
usage history without any authentication.
- An attacker impersonates an administrator to update the usage
history inside the MFP.
3. Availability
- Display, confirmation, and
examination of the usage history or
audit records are no longer available.
- An attacker retrieves backups, tampers with the usage history,
and returns after writing.
- An attacker removes the storage, tampers with the usage
history, and returns the storage to the original location.
- An attacker deletes all the usage history and audit records by
SQL injection.
- An attacker can force quit the history recording process inside
the MFP by a command injection.
- An attacker sends a large volume of requests to the MFP, and
disables the usage history recording on the MFP to conduct
attacks.
87
Developers
- Vulnerability that the usage history and audit records are
tampered due to a lack of examinations of the requests

- Vulnerability that the authentication and authorization of
the users for addition or deletion of the usage history and
audit records are not properly set up, or the allocation
processing cannot be performed properly

- Vulnerability of the usage history published in the folder
that does not require authorization
- Vulnerability that the internal data can be deleted, added,
or updated, due to insufficient examinations of the requests
to the MFP

- Vulnerability that allows bypassing of security functions
by the interfaces which accept requests
- Vulnerability due to insufficient authentication strength
(e.g., administrator passwords are too simple or have not
been changed for a long time, etc.)
- Vulnerability due to a lack of implementation that can
maintain sufficient authentication strength
- Vulnerability caused by a lack of encryption protection of
data in the storage, etc., or the protection is imperfect





- Vulnerability that the files and the processing can be
accessed, due to insufficient examinations of the requests
to the MFP

- Vulnerability that the usage history become unavailable
due to the accumulation of a large volume of requests and
processing (pressure from the processing memory, CPU
processing volume, and bus bandwidth; pressure from
temporary files, document files, and log files)

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.13. Usage history, audit records
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
- Vulnerability that the software functions which record the
usage history can be disabled or are being bypassed

- An attacker deleted the usage history without authentication.
- Vulnerability that the usage history can be deleted
without sufficient authorization

- An attacker deleted the usage history that was placed in a
writable folder.
- Vulnerability that the usage history is recorded at
deletable or rewritable locations

- An attacker removed the storage, accesses the storage from
another computer to delete the usage history, and returned the
storage to the original location.
- Vulnerability that the usage history data on the storage is
not protected

4. Authenticity
- Regarding the deletion of the usage
history or audit records, there is no
proof of who did it, and the recorded
time is not even reliable.
- Because the user attributes are not recorded even if the usage
history inside the MFP is deleted, an attacker can delete the
usage history any time after attacks
- Vulnerability that users are not identified during the usage
history operations

- An attacker adds records to the usage history operation records
inside the MFP by specifying an arbitrary user ID, to make it
impossible to identify the administrator who deleted it.
- Vulnerability that user IDs added during the usage history
operations can be changed to arbitrary value

5. Accountability 6. Non-repudiation
- Regarding the deletion of the usage
history or audit records, the records
of who performed the processing
cannot be specified.
- Although the usage history that was there the day before was
deleted, the individual administrator who did it is unknown.
- Vulnerability that deleting operation of the usage history
is not recorded

- Even if there is a record that a
specific user deleted the usage history
or audit records, it cannot be proved,
because there are no grounds for it.
- The user ID of an administrator was recorded as a user who
deleted the usage history, but the individual who deleted it is
unknown, because an attacker could tamper to an arbitrary
character string.
- Vulnerability that the existing usage history records of the
MFP can be modified

3. Availability
- An attacker impersonates an administrator to stop the usage
history from being recorded, or takes advantage of the input
vulnerability of the MFP to stop the operation of the usage
history, or rewrites the executable code to conduct the normal
terminations without the recording process.
- Display, confirmation, and
examination of the usage history or
audit records are no longer available.
- An attacker deleted the usage history by being authenticated as
a general user.
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.14. Billing information for MFP use
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
7. Reliability
- The usage history or audit records
are not recorded with accurate time,
authentic user IDs, and correct
processing names.
- Some or all of the history of actual
activities are not recorded.
6.14
- The time inside an MFP becomes 1970 when it starts until an
administrator adjusts the time manually. An attacker sends an
unauthorized packet to restart the MFP before the attack, and
attacks the MFP leaving the record of attack as an old record.
When the administrator adjusts the time, the old record of attack
is automatically deleted, and the administrator will not be able
to confirm attacks.
- Because there is a function on the MFP that allows the usage
history and the audit information to be modified later, an
attacker deleted the records immediately after the attack against
the MFP.
- User IDs in the audit records of an MFP are always the same,
so the records of confidential documents retrieved by an
attacker after attacking the MFP cannot be specified.
- Incorrectly processed names or only part of the messages are
recorded due to abnormality of the numerical data range and the
message length for some usage history inside the MFP, so the
attack methods by an attacker cannot be analyzed.
- An attacker sends an unusually long user ID to the MFP so that
a function to record the history will not record the user attribute
information.
Developers
- Vulnerability that the MFP cannot maintain the accurate
time

- Vulnerability that the existing usage history records of the
MFP can be modified

- Vulnerability that the MFP does not record user
information of identified users and authorized users when
recording the usage history
- Vulnerability that the incorrectly-processed names and
value are recorded for some usage history of the MFP

- Vulnerability that user IDs which are recorded in the
usage history or audit records do not reflect the results of
user authentication (always a fixed or undefined value)


Billing information for MFP use
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Billing information and usage
information are leaked to
unauthorized persons.
- An attacker tricks the SQL injection to the request argument,
and retrieves the billing information without proper
authorization.
89
- Vulnerability that the authentications can be bypassed due
to insufficient examinations of the requests to the MFP
Developers

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.14. Billing information for MFP use
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Billing information and usage
information are leaked to unauthorized
persons.
2. Integrity
- Some or all of the billing information for
MFP use is tampered, and appropriate
billing information of users is not
collected or appropriate billing is not
made to users.
Developers
- Billing information is leaked to a third party, because such information
is in the MFP public folder.
- Billing information is leaked to the wrong authority, because attackers
can get the files with the privileges of general users or guests.
- Vulnerability of billing information that is published in
the folder that does not require authorization

- If billing information is accessed via a search function, it is leaked to a
third party due to unauthorized downloading.
- Billing information is leaked to unauthorized users by taking
advantage of the absence of authorization when displaying the billing
information using the console, outputting it to SD memory, printing it
on paper, faxing it, delivering it to inboxes, delivering it to folders in
other systems such as PCs, delivering it via emails, or sending it to
URLs in other systems.
- Vulnerability that allows bypassing of security functions
by opening files through searching
- Vulnerability that allows bypassing of security functions
depending on the types of the output destinations

- An attacker exploits the administrator terminals that are left logged in,
and creates and obtains backups including the billing information inside
the MFP, which results in the leakage of confidential documents, IDs,
passwords, and the session information of the spooled job data.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- An attacker rewrote the usage billing information with the value of
30% less by exploiting an SQL injection, and reduced monthly payment
to the maintenance businesses by 30%.
- Vulnerability that the usage billing information can be
rewritten by a command injection due to insufficient
examinations of the requests to the MFP.
- An attacker impersonated an administrator to rewrite the usage billing
information of the MFP to zero.
- An attacker impersonated maintenance personnel to rewrite the usage
billing information of the MFP as doubled values.
- Vulnerability due to insufficient authentication strength
(e.g., administrator passwords are too simple or have not
been changed for a long time, etc.)
- An attacker specified the usage billing summary API for the remote
maintenance of the MFP to rewrite the usage billing information of the
MFP to zero.
- An attacker inserts an additional process on the http proxy for the
remote maintenance of the MFP, in a manner that the billing number of
the accounting report message is rewritten to zero, and the monthly
pay-per-use to the maintenance businesses becomes zero.
90




- Vulnerability due to a lack of implementation that can
maintain sufficient authentication strength
- Vulnerability of the interfaces that are not open to users
(e.g. remote maintenance interfaces)

- Vulnerability of the external interfaces that are not
authenticated
- Vulnerability that the communication data of the remote
maintenance interfaces are either not protected, or the
protection is imperfect



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.14. Billing information for MFP use
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- Some or all of the billing
information for MFP use is tampered,
and appropriate billing information of
users is not collected or appropriate
billing is not made to users.
3. Availability
- Usage accounting information is not
added even if the MFP is used.
- Billing information cannot be
retrieved because the maintenance
function or the remote maintenance
function becomes disabled or
inaccessible.
4. Authenticity
- Whether the billing information for
MFP use is correct or not is
unknown, so it is unknown even if
the billing information for the MFP is
tampered.
5. Accountability
- It is not possible to determine the
cause even if the billing information
for MFP use is initialized or tampered
to an unexpected number.
- An attacker changed the EEPROM parts inside the MFP, and
wrote the usage billing information to charge excessive fees.
- An attacker removed or destroyed the storage parts that were
to write the usage billing information inside the MFP, and the
MFP continued to be used without recording any billing
information.
- An attacker injected a code inside the MFP to reduce 60% of
the billing to the maintenance personnel by bypassing the
process to add the usage billing only during the time period of
frequent usage of the MFP.
- Vulnerability that the MFP is in a state of being
physically operable by attackers
- Vulnerability that the processing which adds usage billing
is disabled or is bypassed
Developers


- An attacker continuously conducted the wrong maintenance
personnel authentication, so that the maintenance businesses
were not able to login.
- Vulnerability that a function to lock the maintenance
personnel mode for a certain period of time is exploited if
incorrect passwords in the maintenance personnel
authentication are entered a few times in a row (along with
console authentication and remote authentication)
- An attacker impersonated an administrator to delete the usage
billing information.
- Vulnerability that allows administrators to delete the
billing information

- An attacker specified the usage billing summary API of the
MFP, and injected the negative value to change the usage billing
information to reduce the charge.
- Vulnerability that interfaces, which are not open to users,
operate

- An attacker exploited the usage billing summary API of the
MFP, and injected excessive usage value to increase the bill by
60% more than the actual usage billing information to increase
the charge.
- The software inside the MFP did not install a function to
record the operational history of the usage billing information
that was an option.
- The software inside the MFP that records the operational
history of the usage billing information did not have functions
to record user IDs.
91
- Vulnerability that external interfaces which exchange the
usage billing information are not authenticated
- Vulnerability that the source information which adds the
usage billing information is not identified or specified

- Vulnerability that there are no functions to record the
operational history of the usage billing information

- Vulnerability that the operational history of the usage
billing information does not record any of the times, user
IDs or operation types

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.15. Communication system (including Switch, DHCP, DNS, NTP)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
6.Non-repudiation
- Some or all of the usage billing
information for MFP use is deleted or
tampered by some maintenance personnel,
but who specifically did it cannot be
proved.
- After an attacker deleted the usage billing information, the attacker
injected an operational history via API as if a remote maintenance
business deleted it, to make it difficult to determine the user who deleted
it.
- Vulnerability that user IDs are recorded in the record of
operations, but such user IDs can be tampered by users

7. Reliability
- The billing information for MFP use is
no longer an appropriate value under
certain conditions, such as many and big
job data is concentrated, which causes
incorrect billing.
- An attacker continued to input the jobs that took a long time to be
executed to avoid the usage billing information being added, by creating
a certain race condition inside the MFP, and kept executing a large
volume of other jobs.
- Vulnerability related to race conditions and resource
management

- An attacker had made the MFP time significantly deviated at the time
of the attack, so the time of the attack was not properly recorded.
Although it was recorded, it was deleted during the periodic processing
on the next day, as the record was out of the storage period, and the
records were not left. (It is also described in “Accurate time.”)
- Vulnerability that the MFP cannot maintain the accurate time

- As a result of distributed processing of 1,000 copies into four MFPs,
excessive usage was charged for 4,000 copies of work.
- Vulnerability of charging double for the print job data that is
shared with another MFP (bug)

6.15
Communication system (including Switch, DHCP, DNS, NTP)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Wiring or connectors for the MFP to
communicate are exposed, and they are
easily wiretapped by inserting another
device. Radio waves are easily
wiretapped.
- A switching hub or VLAN can be easily
connected without physical restrictions or
authentication, so wiretapping and
third-party mail relay are easily
conducted.
(Communication devices include DNS,
DHCP, and NTP.)
- An attacker inserts a device between the communication system cables
to wiretap unprotected communications as follows, and collects and
records IDs and passwords the mail server.
Unprotected communications: IPv4, IPv6, DHCP, ARP, ICMP, ICMPv6,
LLMNR, Rendezvous, TCP, UDP, UPnP, DNS, TELNET, SNMP,
SMTP, POP3, IMAP4, SIP, FTP, HTTP, SMB, LPR, raw9100, IPP, etc.
92
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect
Developers

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.15. Communication system (including Switch, DHCP, DNS, NTP)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Wiring or connectors for the MFP to
communicate are exposed, and they are
easily wiretapped by inserting another
device. Radio waves are easily
wiretapped.
- A switching hub or VLAN can be easily
connected without physical restrictions or
authentication, so wiretapping and
third-party mail relay are easily
conducted.
(Communication devices include DNS,
DHCP, and NTP.)
2. Integrity
- Unprotected communications of the
MFP is tampered.
- A third-party mail relay is conducted
using a general-purpose interface, such as
USB/SCSI, to tamper with image data and
addresses of the print, scan, and fax.
(Communication devices include DNS,
DHCP, and NTP.)
- USB printer ports of the MFP, USB memory ports, and USB
authentication unit ports, are transmitted via TCP/IP, and extended to
remote locations. However, because the communications are not
protected, confidential documents and card numbers for authentication
are wiretapped and leaked to attackers.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect
- An attacker decrypts the WEP key of the wireless LAN used by the
MFP to retrieve IDs and passwords from the FTP protocol for the
external shared file servers that MFP communicates. The attacker
impersonates an MFP to retrieve documents in the shared file server.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators (policy related
to encryption strength)
- An attacker uses the VLAN distribution protocol on a remote
switching hub to create an Ethernet port that belongs to a VLAN
dedicated to the MFP, and connects to the same VLAN as the MFP.
Then, the attacker impersonates a default gateway of the MFP to
perform a third-party relay attack.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect
- The MFP was not isolated on the network because either the MFP was
connected to the wrong VLAN, or IPsec configuration was wrong. It
was connected to the same network as that of general users, resulting in
the wiretapping of unprotected communications.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators (network cable
connection or incorrect settings)
- An attacker tampers with the host name resolution responses from the
DNS server, because they are not protected, so the requests from the
MFP since then are directed to the host prepared by the attacker.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect
- An attacker inserts a device between the communication system cables
to interfere with unprotected communications, and tampers with IDs and
passwords for the mail servers.
Other unprotected communications: IPv4/IPv6, DHCP, ARP, ICMP,
ICMPv6, LLMNR, Rendezvous, TCP, UDP, UPnP, DNS, TELNET,
SNMP, SMTP, POP3, IMAP4, SIP, FTP, HTTP, SMB, LPR, raw9100,
IPP, etc.
93
Developers





Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.15. Communication system (including Switch, DHCP, DNS, NTP)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
2. Integrity
- Because the response messages from the DHCP/DHCPv6 server were
not protected, the MFP that has received the tampered DHCP response
messages begins to always use the attacker-supplied default gateway
since then.
- Vulnerability that the mutual authentication is not conducted for
the communications between other systems and the MFP

- USB printer ports of the MFP, USB memory ports, and USB
authentication unit ports are transmitted via TCP/IP, and extended to the
remote locations. However, because the communications are not
protected, an attacker interferes to tamper with the job data and the
number of prints that always print one extra copy, so confidential
documents are leaked.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect

- An attacker decrypts the WEP key of the wireless LAN used by the
MFP, and interferes with the MFP communications of the external
shared address servers that are not protected. Then, the attacker adds
him/herself to the group addresses to receive the copies of the files that
are sent to the specific group by the MFP, so confidential documents are
leaked.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators (insufficient
awareness on the encryption strength)

- The MFP was not isolated on the network because either the MFP was
connected to the wrong VLAN, or IPsec configuration was wrong. It
was connected to the same network as that of general users, resulting in
the tampering with unprotected communications.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators (network cable
connection or incorrect settings)

- The MFP becomes disabled due to the
theft of communication device, wire cuts
or theft, or terminal disconnection.
- As a result of disconnecting the Ethernet cable that was connected to
the MFP, an attacker stopped the MFP services which do not require
communication.
- Vulnerability that the MFP is disabled without the
communication system
- The MFP is no longer available, because
the communication devices stop working.
- The MFP services, which do not require communication, stopped, due
to the defect of the switching hub or wireless LAN access point.
- Communication with the MFP or
communication between the MFP and
other systems is not available due to the
incorrect configuration of the
communication systems.
- The MFP cannot provide services due to wrong configuration of the
VLAN, IPsec, or VPN, or the MFP is not connected to the specific
VLAN ports or specific Ethernet ports.
- Unprotected communications of the
MFP is tampered.
- A third-party mail relay is conducted
using a general-purpose interface, such as
USB/SCSI, to tamper with image data and
addresses of the print, scan, and fax.
(Communication devices include DNS,
DHCP, and NTP.)
3. Availability
(Communication devices include DNS,
DHCP, and NTP.)
94
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators (network cable
connection or incorrect settings)


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.15. Communication system (including Switch, DHCP, DNS, NTP)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
4. Authenticity
- The device of the communication
partner cannot be verified as to
whether it is specified by the
prescribed security requirements or
not.
5. Accountability
- The devices used for
communication with the fake source
addresses cannot be specified.
6. Non-repudiation
- Even if there is a record of an
address that specifies the
communication partner, it cannot be
proved when an administrator of the
other side of the system denies it.
7. Reliability
- Proper operation cannot be
implemented, because data sent
through the communication system is
confused with other data, or a portion
of the data received is missing.
(Communication devices include
DNS, DHCP, and NTP.)
(Communication devices include
DNS, DHCP, and NTP.)
(Communication devices include
DNS, DHCP, and NTP.)
- Communication with the NTP servers used by the dozens of
MFPs is not authenticated, which allows accesses by fake NTP
servers.
- Fake host name information is mixed in the responses from the
DNS servers, which leads to fake hosts when files are written in
the external shared folders of the MFP.
- IP addresses of fake DNS servers are injected from the fake
DHCP.
- There is a phenomenon that the time of the MFP varies greatly,
but whether it is a defect of the NTP server is unknown because
there is no record.
- Fake IP addresses are injected into the MFP, but from which
DHCP server cannot be identified to take a countermeasure.
Developers
- Vulnerability that the mutual authentication is not
conducted for the communications between other systems
and the MFP

- Vulnerability that the MFP does not record IP address
configuration, which is set up on the communication
system, as a history on the MFP

- Vulnerability that user IDs are recorded in the
communication record, but such user IDs can be tampered

- It contains data to attack vulnerabilities in the DNS responses,
but which host injected or responded cannot be identified,
because there is no record.
- Although the communication record contains user IDs, it is
disabled as a proof, because arbitrary user IDs can be input.
- Because the communication record is injectable from any
hosts, records by attackers are mixed, and the cause of the
defect cannot be specified.
- Because it is possible to impersonate other hosts using the
group key that is used between the communication partners
connected by IPsec, the user terminal assumed to be attacked
from the connection record cannot be identified.
- If the loading of the communication systems exceeds the
capacity, IP packet loss generates. Consequently, the MFP
performs the retransmission processing, but a race condition or
a resource shortage occurs because the processing load
increases in the MFP. The process can be interrupted or remain
incomplete while still processing.
(Communication devices include
DNS, DHCP, and NTP.)
95
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
- Vulnerability due to race conditions or a resource
shortage


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.16. Remote management system
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
7. Reliability
- Proper operation cannot be
implemented, because data sent
through the communication system is
confused with other data, or a portion
of the data received is missing.
- An attacker sends complex multi-type requests to the DNS,
DHCP, and NTP servers. However, the MFP cannot receive
appropriate responses because some packets or response
messages are either missing or changed due to race conditions
in the servers.
(Communication devices include
DNS, DHCP, and NTP.)
- An attacker intrudes any of the DNS, DHCP or NTP servers by
taking advantages of known vulnerabilities to execute arbitrary
codes. The MFP either cannot receive appropriate responses, or
the above-mentioned servers attack the other related systems,
such as the MFP.
6.16
- Vulnerability on other systems
Developers

Remote management system
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
[During the use of remote management
functions]
- The use of the unauthorized remote
management functions.
- Shared files with confidential
information and multiple addresses stored
inside the MFP are leaked via remote
management functions.
[Remote management system itself]
- External address book and the backup
data are leaked to attackers by attacking
the management systems.
- An attacker wiretaps the unprotected communication among
communications that send and receive address books of the MFP, and
the contents of the address books are leaked to the attacker: registration
and update of the address books; backups of the address books; address
book synchronization for defining single fax delivery, mail delivery, and
server delivery; address book synchronization for defining multiple
delivery processing; and references of address books for control from
other systems.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect
- An attacker intrudes using vulnerabilities on the configuration
management servers or imposes on requests, and obtains the same data
as the address book used on the MFP or the backup data of the MFP that
are stored on other systems
- Vulnerability of the other systems
- An attacker intrudes any of the management servers, authentication
servers, or audit servers by taking advantages of known vulnerabilities to
execute arbitrary codes. The MFP either cannot receive appropriate
responses or the above-mentioned servers attack the other related
systems, such as the MFP.
96
Developers


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.16. Remote management system
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
2. Integrity
[During the use of remote management
functions]
- Addresses that are input or retrieved
to/from the MFP, and the configuration
information, are tampered.
- An attacker interferes with the communications between the MFP and
the maintenance terminals or administrator terminals by using the ARP
impersonation on the communications paths. The attacker then tampers
with the addresses that are input into the MFP to add attacker’s own
address, and continues to wiretap confidential documents.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect

[Remote management system itself]
- Configuration information of the
external management systems is
tampered, and the MFP behaves
unexpectedly.
- Interface ports to perform remote maintenance of the MFP should be
closed by default, but are open. An attacker connects to the ports to
exploit the remote maintenance function.
- Vulnerability that the API or parts of the remote service
interfaces of the MFP still have the API running, which can be
executed by the commands with administrator privilege.

- By exploiting the CSRF vulnerability of the remote backup functions
of the MFP, an attacker causes the web browser of administrators or
maintenance personnel to open the specific URL, and performs arbitrary
administrative functions.
- Vulnerability that the CSRF attacks against the terminal
browsers of administrators and maintenance personnel are
successful

- An attacker tampers with the messages of the configuration change
instructions to the MFP from the unprotected configuration systems, and
the destroyed configuration data is registered with the MFP, which
causes either the MFP to stop or certain function to become unavailable.
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect

- An attacker impersonates a user terminal to access the remote
management interfaces of the MFP, and attempts authentication many
times using IDs and passwords. Then, the authentication server for the
MFP detects the consecutive login failures, and prohibits the
administrator login for a while (a few minutes). By performing this task
continuously, other management functions of the MFP are disabled.
- Vulnerability that a function to reject login by administrators is
exploited when the authentications continue to fail
- An attacker prevents the collection of the operational information of
the MFP by taking advantage of the vulnerability of the monitoring
server to stop the monitoring server.
- Vulnerability of the remote management systems (in cases of the
remote management system prepared by developers)
- Parts of the authentication servers are
changed, or parts of the authentication
data are tampered to disable services.
3. Availability
[During the use of remote management
functions]
- Destroyed settings are input into the
MFP by an attacker, and either the MFP
becomes unavailable or defects.
[Remote management system itself]
- Responses of the authentication servers
stop, and the MFP becomes unavailable.
- Responses of the audit servers stop, and
the operational information becomes
unavailable.
- Responses of the configuration
management servers stop, and the new
addresses are no longer added. Address
book research becomes unavailable.
- An attacker prevents the address selection on the MFP by taking
advantage of the vulnerability of the configuration management server,
and by deleting the shared address books to synchronize the MFP with
empty address books.
97

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.16. Remote management system
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
4. Authenticity
[During the use of remote
management functions]
- The authentication request
responses, address book responses,
configuration setting change
requests, and maintenance requests
from remote management systems
are not from the authorized remote
management systems.
[Remote management system itself]
- Whether some management servers
and authentication servers handle the
requests to the specific MFP
correctly cannot be confirmed.
Developers
- Either using the authentication servers that are correct or the
systems that are not verified by the MFP, an attacker prepares a
fake authentication server to communicate with the MFP to
exploit the MFP by making another malicious terminal
impersonate a user.
- Vulnerability that the mutual authentication is not
conducted between remote management systems and the
MFP

- An attacker impersonates a monitoring server of the MFP, and
sends a large number of monitoring request messages to the
MFP to overload the MFP.
- Vulnerability due to unprotected communication between
the remote administrative systems and the MFP

- Vulnerability that the mutual authentication is not
conducted between remote management systems and the
MFP

- An attacker makes an administrator open the specific URL,
conducts CSRF attacks against usage terminals of the
administrator to make the administrator obtain backup data of
the MFP and forward to the attacker-supplied folders that can be
obtained by fraud, and the attacker obtains the backup data of
the MFP.
- Vulnerability that the CSRF attacks against the terminal
browsers of administrators and maintenance personnel are
successful
(It is not examined that requests for important operations
and functions have associations with the information
specific to the previous operation in the stateless
communication (HTTP, etc.) after the authentication
between the MFP and other systems.)

- An attacker tampers with response messages to the MFP from
the address book server on the communications paths, and
changes the address with the attacker's address to obtain
confidential documents.
- Vulnerability due to unprotected communication between
remote administrative system and the MFP, or that the
protection is imperfect

- An attacker hijacks the control of the authentication server to
execute arbitrary codes by taking advantage of the known
vulnerabilities, and makes it response that the authentication of
the remote management system required by the MFP is all
correct. As a result, the MFP accepts the connections from the
fake management servers.
- Vulnerability of the authentication servers (in cases of the
remote management system prepared by developers)

98
Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.16. Remote management system
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
5.Accountability
[During the use of remote
management functions]
- Requested processes by the MFP
from remote management systems or
responses from remote management
systems, are supposed to be recorded
inside the MFP, but are not.
[Remote management system itself]
- Investigation cannot be conducted
when there is a defect, because the
history that remote management
systems requested, as to which MFP,
and the results as well as failure
reasons, are not recorded with the
remote management systems.
6. Non-repudiation
[During the use of remote
management functions]
- When requests are made from
remote management systems, it
cannot be proved that the names of
the authentication servers,
monitoring servers, and management
servers are not tampered or
impersonated.
[Remote management system itself]
- When requests made by some
MFPs to other MFPs from the remote
management system are recorded, it
cannot be proved that the names of
the hosts and the user IDs are not
tampered or impersonated.
Developers
- Because the history of communications to the address book
was neither recorded in the MFP nor in the address book server,
it was unknown that an attacker searched for and requested the
address book data externally to retrieve it, and sold it to outside
contractors. .
- Vulnerability that the communication history is not
recorded between remote administrative systems and the
MFP

- There is a missing piece in the monitoring server records, but
there was no time described in the communication history with
the remote management system. Because the type of processing
that was conducted by the MFP during the period without
monitoring records cannot be specified, no measures are taken.
- Vulnerability that the communication history with remote
management systems does not record any of the times,
user IDs, or operation types

- A request is made to the MFP from the configuration server,
which performs configuration changes with the administrator
privilege, but the request is not found in the MFP. When and
what requests are sent by the configuration server cannot be
confirmed, because there is no history in the configuration
server, so no measures can be taken.
- Vulnerability that the communication history is not
recorded in remote administrative systems

- There was a record of using the management functions of the
MFP via remote management system that an administrator
illegally takes out the backup data inside the MFP. However, an
attacker cannot be identified, because arbitrary value can be
injected into the operational history inside the MFP, or there is a
vulnerability of possible tampering.
- Vulnerability that the IP addresses of the remote
management systems are recorded in the record of
operations, but such IP addresses can be tampered

- There was a record in the remote monitoring system for the
MFP that a specific MFP was performing normally. Because the
state notification sent by an attacker is fake, the anomaly
detection cannot send an alarm when it is attacked by the
attacker (SNMP).
- Vulnerability that the remote administrative systems do
not verify the validity of the MFP to be monitored

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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.16. Remote management system
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
Developers
7. Reliability
[During the use of remote management
functions]
- The MFP cannot perform processing
with remote management systems.
- When a URL that is in the email text sent by an attacker is opened on
the browser of the administrator terminal, an unauthorized JavaScript
code is executed. Then, the attacker copies all the address contents of the
shared address book server that the administrator is logged in.
- Vulnerability that the CSRF attacks against the terminal
browsers of administrators and maintenance personnel are
successful

- MFP cannot process the multiple
requests from remote management
systems in the order in which they are
received, or by priorities, causing
irregularity.
- When requests to the MFP become more than a certain number, the
authentication responses from the authentication server to the MFP no
longer can be properly handled, which give an unintentional privilege to
a third party. An attacker takes advantage of this to obtain administrator
privileges.
- Vulnerability that the configuration information is destroyed by
changing settings of the same MFP by multiple users at the same
time

- Not all the requests accepted are
processed, and a part of them is not
processed. Parts of the requests are
replaced with other requests, or parts of
the processing are redundantly processed.
- When a certain type of pending job data increases, the address to be
deleted remains, because the instructions to be processed in the order of
deletion and addition is reversed for making changes to the address book
inside the MFP from the management server. Then, an attacker takes
advantage of this to send fake messages to the other MFP users, because
remaining addresses become outside of its control.
- Vulnerability related to race conditions and resource
management

- Some requests that are accepted are
processed repeatedly, and never stop.
- During the processing of a large volume of job data, updating of the
address book is interrupted due to a resource shortage in the MFP.
[Remote management system itself]
- The MFP cannot perform processing due
to defects in the remote management
system itself.
- Because the times inside the several MFPs are all different, it takes a
few extra hours to confirm the completion of the distributed processing
on multiple MFPs by the monitoring server.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- Because an attacker intrudes the remote management systems by taking
advantage of the vulnerability of the remote management system, the
remote management system can no longer handle certain responses in
the correct order, and the MFP does not work properly.
- Vulnerability of the remote management systems

- An ID and password of a general user is leaked, while this general user
has administrator privilege and uses the same ID and password as an
administrator. An attacker connects remotely to the MFP as an
administrator to retrieve all the configuration information, IDs, and
passwords, and sells confidential documents and addresses while using
them to attack other hosts.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- Although the SNMP has monitored a certain MFP, the monitoring is no
longer available because it became undefined value after the byte
counter of job data is flooded with 32 bits, or because the comparison is
not possible due to packet data volume that is also counted with the job
data volume.
- Vulnerability that the state value of the MFP that responds with
SNMP is wrong (wrong measurement methods, measuring object
and the response target value are changed, improper numeric
conversions and type conversion)
- Either the authentication servers accept
user IDs mistakenly, or the MFP stops
working, because parts of the passwords
being processed are missing.
- The results are unexpected, because
monitoring servers monitor the wrong
MFPs.
- Appropriate addresses cannot be
retrieved because of the missing address
data in the shared server of address book,
due to mishandling.
100

Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.17. User terminal
6.17
User terminal
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- IDs and passwords for the
authentication that are stored in the driver
software executed on the user terminals
are leaked.
- Because spool files stored in the user
terminals are not protected, the
documents and addresses in the spool
files are leaked.
- The MFP model and addresses are
identified through the regular state
confirmation query to the MFP from the
user terminals.
- By the cross-site request forgery attack against user terminals, it makes
users print, fax, or deliver the documents with the transmission history
of the users to arbitrary addresses, and those documents are leaked to
attackers.
- Vulnerability that it is not examined that requests for important
operations and functions have associations with the information
specific to the previous operation in the stateless communication
(HTTP, etc.) after the authentication between the MFP and other
systems)

- An attacker takes advantage of the vulnerabilities of the driver API for
the MFP or SDK API for the MFP on the user terminal to execute
arbitrary codes, and send copies of confidential documents to arbitrary
addresses.
- Vulnerability of the driver software for the MFP provided by
MFP vendors or the MFP SDK library (numerical processing,
information leakage, input confirmation, security functions, race
conditions, resource management) (print driver, fax driver, scan
driver)

- An attacker manipulates the malware that is already running on the user
terminals to obtain the addresses and passwords that are set up for the
drivers for the MFP, or spool files that contain confidential documents.
- Vulnerability that digital certificates, IDs, and passwords are
stored without any protection on the driver for the MFP of the
user terminals

- An attacker wiretaps unprotected communications between the user
terminals and the MFP, and retrieves the IP addresses, model, user IDs,
and passwords of the MFP to prepare for attacks.
- Vulnerability due to unprotected communication between the
MFP and other systems (other MFPs, user terminals,
accumulation and external processing, remote management
systems)
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- The malware exploiting the vulnerability of the applications other than
the MFP was running in the user terminals, and the copies of the files
that were exchanged with the MFP, including the input and output of the
scan and print, were transferred to the attacker.
2. Integrity
- The driver software that runs on the user
terminals or the condition of the running
software is tampered by attackers to
execute arbitrary code.
- Configuration information setup for the
driver software that is stored in the user
terminals and the authentication
information are tampered.
- Messages between the MFP and user
terminals are tampered.
Developers
- An attacker takes advantage of the vulnerabilities of the driver API for
the MFP or SDK API for the MFP on the user terminal to execute a code
that attacks a certain vulnerability, takes control of user terminals, and
tampers with the job data.
- Vulnerability of the driver software for the MFP provided by
MFP vendors or the MFP SDK library (numerical processing,
information leakage, input confirmation, security functions, race
conditions, resource management) (print driver, fax driver, scan
driver)
- An attacker infects user terminals with malware, rewrites the
configuration information, IDs, and passwords of the driver for the MFP
on the user terminals, and makes users send confidential documents to
the attacker as well, which were supposed to be sent only to the MFP.
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators
101



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.17. User terminal
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
3. Availability
- The MFP is disabled because the
driver software that is executed in the
user terminals is either deleted or
destroyed.
- The MFP is disabled because
configuration information setup for
the driver software that is stored in
the user terminals or authentication
information is either deleted or
tampered.
Developers

- Due to interference by fake ARP on the communications paths
of the user terminals and the MFP, interference by fake wireless
LAN, and interference by fake proxy server, an attacker tampers
with the job data between the user terminals and the MFP, and
sends copies of confidential documents to him/herself.
- Vulnerability due to unprotected communications
between other systems and the MFP, or that the protection
is imperfect
- The malware exploiting the vulnerability of the applications
other than the MFP was running in the user terminals, and the
copies of the print images were delivered to the attacker as well
because the spool files at the time of printing have been
tampered.
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators

- The MFP is disabled because the driver for the MFP installed
on the user terminal is already destroyed.
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators
- Vulnerability of the driver software for the MFP provided
by MFP vendors or the MFP SDK library (numerical
processing, information leakage, input confirmation,
security functions, race conditions, resource management)
(print driver, fax driver, scan driver)

- The MFP is disabled because the user terminal has been
intruded, and the setup information of the driver for the MFP is
either deleted or destroyed.
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators

- An attacker inserts the session completion messages to the
sessions communicating between the MFP and the general user
terminals to force quit the session (wireless LAN, TCP,
SSL/TLS).
- An attacker sends a large number of requests to the service
ports on the user terminals or service ports on the MFP, to stop
the services.
- The malware exploiting the vulnerability of the applications
other than the MFP was running on the user terminals, and when
a certain MFP was used to print, the copies were transferred to
an attacker because the printing was performed only for the
specified MFP.
- Vulnerability due to unprotected communications
between other systems and the MFP, or that the protection
is imperfect

- Vulnerability of race conditions or a resource shortage on
the service ports for user terminals

- An attacker takes advantage of the vulnerabilities of the driver
API for the MFP or SDK API for the MFP on the user terminal
to terminate or go out of control of the user terminal, and
disables the MFP.
- The MFP is disabled because the user terminal has been
intruded, and the driver for the MFP is deleted.
102
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.17. User terminal
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
- The driver software to be installed on
the user terminals cannot be verified as to
whether it is the right software for the
MFP.
- The driver software for the MFP installed on a user terminal comes
with malware. Because there was no warning, the user continued to use
it, and it caused the leakage of confidential documents.
- The user terminal that the driver
software for the MFP to be installed on
cannot be verified as to whether it is the
right terminal to use the MFP.
- A user terminal uses an unmodified OS with known vulnerabilities, and
it was already infected with malware. The driver for the MFP was
installed to allow the attack to stop services to the MFP.
5. Accountability

4. Authenticity
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators
Developers
- Whether the software in the user
terminals is used by authorized users with
the right procedure cannot be confirmed
retroactively.
- A fake order instruction arrives at a company via fax with the name of
the company as a sender, but the individual sender cannot be identified.
- Vulnerability that the user authentication is not conducted to use
the MFP for faxing

- A large number of prints are output from the MFP, but the individual
who performed the output cannot be identified.
- Vulnerability that there is no functions to record the
authentication results of MFP users along with the operational
history

- Vulnerability that a function to record the authentication results
of MFP users along with the operational history is not used
6.Non-repudiation
- It cannot be proved by showing
evidence, regarding impossible tampering
with the operational records recorded by
the driver software and the processing
records.
7. Reliability
- Applications related to the driver
software of the user terminals either
mistakes the data or causes data to go
missing.
- When the driver processes the operation record every time the driver
software is used on the OS of the user terminals, the information in the
usage history is disabled because the operation record can be tampered,
such as inputting an arbitrary character string to the operation record.

- Vulnerability that the host names of the user terminals are
recorded for its operations, but such host names can be tampered

- Vulnerability of the driver software provided by MFP vendors
(numerical processing, information leakage, input confirmation,
security functions, race conditions, resource management) (printer
driver, fax driver, scan driver)

- The usage history recorded on the user terminals was not available
because it was tampered by the malware infecting the user terminals.
- The control of the driver software is
hijacked, and jobs are replaced as jobs of
the different data and the different users.
- When the printing is executed that contains the specific data, the prints
do not come out as expected, or confidential documents are leaked
because other job data or printing files’ contents are mixed in the
printing results.
- By taking advantage of the vulnerability of the printer driver, an
attacker hijacks the control of the printer driver to rewrite the printer
driver settings, and sends duplicates of the print to the attacker as well
when the printing is executed, so confidential documents are
continuously leaked.
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.18. Accumulation and external processing (Spooler, shared folders, emails, other business systems)
6.18
Accumulation and external processing (Spooler, shared folders, emails, other business systems)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
1. Confidentiality
- Documents are leaked by wiretapping
on the communications paths, because the
communication conducted by the
accumulation and external processing
servers is not protected.
- Confidential documents that are
retrieved from other systems by the MFP
for the specific processing are leaked on
the MFP.
- Confidential documents are leaked on
the accumulation and external processing
servers (servers for accumulating
documents, proxy servers, or content
converting servers).
- An attacker wiretaps the unprotected communications between the
MFP and accumulation and external processing servers to obtain the job
data that contains confidential documents. The attacker sells the obtained
data, and the confidential information is leaked.

- Vulnerability due to unprotected communication between other
systems and the MFP, or that the protection is imperfect
- When documents are delivered to multiple destinations at the same
time, part of the communication to deliver to some MFPs is not
protected, because multiple MFP models and multiple MFP vendors are
used. An attacker wiretaps only unprotected communications and
confidential documents are leaked.
- Some general users are able to view unauthorized files in a shared
folder outside of the MFP if they make delivery requests on the MFP,
causing the leakage of confidential documents to outsiders.
- Vulnerability that there is a difference in attributes of authors
or privileges of files between the MFP and other systems

- On a website, image data scanned on the MFP is always stored in the
specific public folders of the external shared folder, so someone may
mistakenly replaces them with materials that have similar document
names to cause the leakage of confidential documents to unauthorized
persons.
- Vulnerability of the security policy leakage or insufficient
awareness on security policy among administrators

- When documents are delivered to multiple destinations at the same
time, functions are misused, such as delivery, confidential, box, send,
print, mail, server transmission, and URL transmission, because the
terminology varies depending on MFP vendors while MFPs of multiple
MFP vendors are used. It causes unnecessary printing, or copying of
documents to the improper servers, so confidential documents are leaked
to outsiders.
- An attacker intrudes in the spool servers where the job data to the MFP
is accumulated, and copies such job data for him/herself to obtain
confidential information that is contained in the job data.
2. Integrity
- Documents or addresses are leaked on
the accumulation and external processing
servers (servers for accumulating
documents, proxy servers, or content
converting servers).
Developers
- An attacker interferes with the unprotected communications between
the MFP and the accumulation and external processing servers, tampers
with the job data that contains confidential documents, and makes the
support center send new passwords to users to obtain confidential
documents.
104

- Vulnerability of complex setting conditions which lead to
erroneous operations, as well as confusing results
- Vulnerability of the other systems
- Vulnerability due to unprotected communications between other
systems and the MFP, or that the protection is imperfect


Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.18. Accumulation and external processing (Spooler, shared folders, emails, other business systems)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
2. Integrity
- Documents or addresses are leaked
on the accumulation and external
processing servers (servers for
accumulating documents, proxy
servers, or content converting
servers).
3. Availability
- Accumulation and external
processing servers either stop or
defect by termination, defect, or
hijacking of the MFP.
- Accumulation and external
processing servers stop, causing the
MFP is disabled to the users.
- An attacker impersonates an accumulation and external
processing server, which returns fake temporary responses to the
MFP. The MFP redirects and connects to the fake accumulation
and external processing server that is prepared by the attacker.
- On the spool servers or file servers that store scan results, the
job data or scan result files are stored in the rewritable public
folders without authentication, so the attacker can delete all of
them.
- An attacker intrudes in the spool servers by exploiting the
vulnerability of the spool servers that the job data is intensively
input to the MFP, and tampers with the job data that contains
confidential information.
- An attacker performs fuzzing test against the ports that the
MFP communicates with accumulation and external processing
servers, and creates messages that intrude against the specific
vulnerability to send it to the specific MFP using malware
infected with general PCs. The MFP that received such
messages either stops or defects, so it is disabled.
- An attacker inserts messages, such as “communication
completed” or “message ends,” by impersonating against the
specific sessions between the MFP and the accumulation and
external processing server to abnormally terminate the sessions.
- An attacker inputs a large volume of job data that permits load
distribution processing to the MFP that has a load distribution
configuration. It disables multiple MFPs at the same time,
including the MFP to be load distributed.
- An attacker stops the shared file servers by taking advantage of
the vulnerability of the shared file servers, and disables the MFP
scanner function as well as the fax delivery function for the file
forwarding via the shared file servers.
105
Developers

- Vulnerability due to unprotected communications
between other systems and the MFP, or that the protection
is imperfect
- Vulnerability of the security policy leakage or
insufficient awareness on security policy among
administrators

- Vulnerability of the other systems

- Vulnerability that the MFP specifies the hosts or servers
that connect to the ports to communicate with
accumulation and external processing servers, but no
restrictions apply

- Vulnerability of unprotected communication between the
MFP and the accumulation and external processing servers

- Vulnerability that the mutual authentication is not
conducted between the MFP and the accumulation and
external processing servers

- Vulnerability of the MFP that stops or defects if it
receives unexpected data through the communication ports
of other systems
- Vulnerability that cannot restrict the processing demand
to its acceptable capacity

- Vulnerability that no restrictions set on the processing
demand to its acceptable capacity
- Vulnerability of the accumulation and external
processing servers



Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.18. Accumulation and external processing (Spooler, shared folders, emails, other business systems)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
4. Authenticity
- Documents and addresses are
sent/received between the MFP and
fake accumulation and external
processing servers.
5.Accountability
- A server that transfers the data
processed by the specific
accumulation and external
processing servers cannot be
confirmed. The cause of the defects
cannot be identified.
- Whether the correct route is used
for communication cannot be
confirmed.
6. Non-repudiation
- The certainty of the information
that identifies the server cannot be
proved by showing evidence,
regarding the processing records of a
specific accumulation and external
processing server.
- Confidential documents are leaked to attackers because digital
files are stored in the fake shared file server that the attacker has
operated.
- Vulnerability that the mutual authentication is not
conducted between the MFP and the accumulation and
external processing servers
- A fax mail was sent to the MFP via the fake mail server that an
attacker has operated, and a user sent money to the wrong
account after receiving a fake billing fax impersonating an
sender.
- There is no record in the MFP when an attacker sends fake
delivery requests to the MFP by taking advantage of a
vulnerability of a certain mail server, so no measures are taken
because the mail server used for the attack is not identified.
- Vulnerability that there is no mutual authentication
configuration between the MFP and the accumulation and
external processing servers
- For communication between the accumulation and external
processing servers and the MFP, there was a large number of
communication history of authentication failures recorded.
Because the host name of the communication partner was forged
on the DNS server, the server could not be identified from the
host name.
- IP addresses are recorded at the time of authentication in the
transfer records with the accumulation and external processing
servers. However, an attacker can use non-recorded IP addresses
to make attacks using the session information, because services
can be used from other IP addresses.



- Vulnerability that the communication history with the
accumulation and external processing servers is not
recorded.
- Vulnerability of the accumulation and external
processing servers
- Vulnerability that the host names that are reversed can be
forged in the DNS, among those obtained from the
communication history recorded on the MFP with user
terminals
Developers


- Vulnerability that the IP addresses of accumulation and
external processing servers are recorded for the operational
history, but such IP addresses can be tampered

- Vulnerability that the communication history with the
accumulation and external processing servers is not
recorded.

- Vulnerability that the communication history with the
accumulation and external processing servers does not
contain enough records

- The data in the transfer records between the accumulation and
external processing servers and the MFP is found to be tampered
by SQL injection, so it is disabled to investigate causes.
- During the multi-stage delivery using the fax relay function, it
shall be ensured that the unauthorized fax is not relaying in the
middle of the transmission , but some items in the
communication record that show from where the incoming fax
calls came are missing in the second stage of mail faxing, so its
route cannot be confirmed.
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Research Report on the Security of MFPs
6. Vulnerabilities assumed from threats
6.18. Accumulation and external processing (Spooler, shared folders, emails, other business systems)
T. Threats to these secondary
assets
M. Examples of attack methods or incidents that realize
these threats
V. Vulnerabilities that may cause the examples of
attack methods or incidents
Those who should take
measures
Users
7. Reliability
- Job data that the MFP received
from accumulation and external
processing servers is corrupted.
- Job data that is sent from the MFP
to accumulation and external
processing servers is neither
correctly saved nor processed.
Developers
- An attacker impersonates the specific operation server to the
MFP, and returns fake response messages. An SQL injection is
used to the fake HTTP response messages, and it destroys the
database inside the MFP.
- Vulnerability that the SQL command can be entered due
to insufficient examinations of the requests to the MFP

- Vulnerability of unprotected communication between the
MFP and the accumulation and external processing servers

- When the specific data acquisition requests to the specific
business systems are sent from the MFP, either failure responses
are returned, or session time-outs occur. However, the software
inside the MFP repeats the processes until a success response is
returned, which causes a resource shortage because multiple
processes start up since then.
- Vulnerability of insufficient race conditions and resource
management

- An attacker inputs processing requests to another MFP that are
sent from the MFP for the load distribution, makes the spool
server redirect again to input, and indefinitely makes the job
data to be cyclically processed.
- Vulnerability that identification information is not
confirmed, such as the destinations of job data

- Vulnerability of unprotected communication between the
MFP and the accumulation and external processing servers

- Fax images and scanned image files sent from the MFP are not
saved properly and become unavailable, because external file
servers are intruded by taking advantage of their vulnerabilities.
- Vulnerability of the accumulation and external
processing servers
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Research Report on the Security of MFPs 7. Detailed description of vulnerabilities
7. Detailed description of vulnerabilities
In this chapter, items that should be noted in particular are discussed in detail among the
vulnerabilities related to the MFP listed in the previous chapter. Specifically, well-known
attack methods that are open to the public and became topics in recent years, as well as the
vulnerabilities that have been reported as actual cases, are described comprehensively.14
Each description shows an overview, explanation, and measures for vulnerabilities.
Specific attack methods related to the vulnerabilities are presented in the description.
Measures are listed by users (mainly administrators), developers, and evaluators, and are
intended to be the references for the vulnerabilities of the MFP from their own
perspectives. “Evaluators,” who are concerned parties seen in this chapter for the first time,
are those who are in a position to confirm vulnerabilities of the MFPs, such as third parties
to conduct vulnerability testing services of the MFPs and the persons in charge of the
development vendors who conduct their own inspection of the security functions.
7.1
Assumptions about attacks
As mentioned in Section 1.5, the vulnerabilities related to the MFP described in this
chapter are not necessarily applied to all the MFPs, but it is assumed that the MFP should
have the functions concerned, and those functions should be available to operate.
The attacks in this report mean the acts for the purpose of tampering with or viewing by
unauthorized users or unauthorized third parties to access protected assets defined in
Chapter 5. For example, the following acts are considered to be attacks:
1)
2)
3)
Third parties or users access to protected assets of other users.
Third parties or users access to unauthorized protected assets by using
administrator functions or maintenance functions.
Third parties or users access to unauthorized protected assets by putting the MFP
into an abnormal state.
On the other hand, accessing users’ protected assets by maintenance personnel or
administrators of the companies that introduced the MFP is possible by using privileges
such as, for example, functions to initialize (change) passwords. However, the restrictions
on these functions shall be addressed in the policies and provisions of the companies that
have introduced the MFP or MFP vendors themselves. Therefore, for the operating
conditions of the MFP, it is assumed in this report that the concerned parties who have
privileges, such as administrators and maintenance personnel, perform appropriately. The
security in the manufacturing and delivery of the MFP is also assumed to be assured.
Manufacturing and delivery processes are discussed in Chapter 8.
7.2
Seriousness and attack potential evaluation
The values of the seriousness and attack potential evaluation that are described in the
detailed description items refer to the results of the calculations using the CVSS
calculation tool15 for the accessibilities to the vulnerabilities described, and the attack
potential required, respectively.
Vulnerabilities related to the MFP listed on CVE (Common Vulnerabilities and Exposures Number)
from January 2010 to July 2012 are all categorized in the items described in this report.
15 http://jvndb.jvn.jp/cvss/ScoreCalc2.swf?lang=ja&g=1
14
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In the CVSS 2.0 Base, chances of being attacked increase as the color becomes redder.
CVSS 2.0 Base: Caution →
Warning → Danger
High possibilities of being
attacked
Figure 7-1 Attack potential diagram
Regarding the vulnerabilities in the following description, some vulnerabilities are not
easily prevented in reality with measures only focusing on the MFP functions; such as the
attacks described in “1. Confidentiality” in Section 6.3, which require advanced technique
with limited chances; i.e., the operating MFP in a company is opened without anybody
noticing it, and the RAM (volatile memory) is quickly cooled and is taken to a place with
facilities that enable it to be used for attacks within a short time while the data is still
available to analyze. Such vulnerabilities do not even appear on CVE, etc. This chapter,
therefore, comprehensively describes the items that users, developers, and evaluators shall
recognize and take measures for, and the items most likely to be attacked as real problems
at the present time.
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7.3
Problems with data protection of the storage media
The typical storage media that has been built into the MFP in recent years is the HDD. The
MFP that is assumed to handle protected assets shall protect assets, such as temporarily stored
confidential document data on the HDD, configuration information, and passwords of users and
administrators that are permanently stored. On the other hand, an HDD that is built into an MFP
is easy to view, and it usually can be removed or replaced. Therefore, even if an HDD falls into
the hands of attackers, a mechanism that does not allow the leakage of data (protected assets)
on the HDD is needed.
It is basic, but the full-spectrum encryption of the HDD is considered to be as secure as security
measures for the protected assets stored on the HDD. The encryption of some data on the HDD
and the lock using HDD passwords are known to be vulnerable. In recent years, however, there
are no MFPs that are security-conscious, for example HDDs are protected only by locking
passwords, among products of the Japanese MFP vendors.
7.3.1 [HDD encryption]
The first attack that shall be kept in mind is performed as an attacker removes the HDD from
the MFP that has no full-spectrum encryption on the HDD to read the stored protected assets by
connecting to PCs or other MFPs. This attack is easy for users who can access the MFP directly
in the local environment. The risk of such attack is high, and the necessary attack potentials are
low. In addition to the removal of the storage medium, such as an unencrypted HDD, etc.,
which is also scored in this section, the attacking procedures are discussed with the assumption
that the HDD is implemented with encryption, since most MFPs are implemented with
encrypted HDDs nowadays.
The measures for HDD encryption are also effective for the MFP that is implemented with the
hibernation function (to hibernate). Because the protected assets in the volatile memory are
temporarily deployed on the HDD, there is a possibility that such protected assets in the volatile
memory (basically, attack on such assets is difficult) are leaked by removing the HDD in a
hibernation state.
7.3.2 [Full-spectrum deletion at the time of disposal]
In cases when users return leased MFPs or dispose MFPs, it is desirable to bring back the
conditions in which the data on the HDD cannot be recovered by performing the full-spectrum
overwrite deletion of the contents of the HDD, which is built into the MFP. There are some
overwrite deletion methods, such as Pentagon (DoD5220.22-M)16 and The Gutmann overwrite
method17 that are said to make data recovery impossible. These methods have been actually
introduced in the current MFPs. If an attacker obtains the MFP after its disposal, he/she would
have to spend a very long time performing an attack. Even if it is encrypted by a
computationally secure algorithm, it is desirable to perform a full-spectrum overwrite deletion
of the storage medium in consideration of the leakage of keys and passwords to create keys.18
http://www.usaid.gov/policy/ads/500/d522022m.pdf
http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
18 In cases when the keys are created from the passwords entered by the users, such keys may be leaked by
a dictionary attack, etc., performed over a long time.
16
17
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7.3.3 [Attack methods and measures]
An attack in which a user (an attacker) removes a full-spectrum encrypted HDD from the MFP
and replaces it with the HDD encrypted with his/her own key, is discussed in this section. Using
this method, the protected assets recorded on the HDD of the MFP are stored in a format that
the attacker can read which results in the loss of confidentiality of the protected assets.
To make this attack successful requires some conditions. A key to decrypt the existing HDD is
not needed, but the attacker needs to set a key to decrypt the replaced HDD to the MFP. In cases
when the decrypted data are exchanged between the MFP and the HDD, equipped with an
encryption chip, an attacker can copy the MFP configuration information without anybody
noticing that the HDD was replaced.19 It is appropriate to establish the same settings as for an
operating MFP, because it is impossible to read such configuration information on the
encrypted HDD that is removed, when the configuration information is on the HDD. In such
case, however, the attacker may need to have the same type of MFP. In cases of the MFPs that
store the configuration information in the nonvolatile RAM instead of on the HDD, this
preparation may not be necessary.
For measures against such attacks of replacing the HDD, functional measures, specifically,
functions that uniquely identify and validate the HDD are effective. The information that can
uniquely identify the HDD that has been used (the hash value of the unique identifier for the
individual HDD) shall be kept on the HDD, and it is desirable to have an error but not to
operate when the HDD is replaced. As long as the function for entering keys for the HDD
decryption is not available to the users who will be the attackers (unless they are entered using
the management or maintenance functions, etc.), the replaced HDD is no use.20
Supplement: Implementation of the right cryptographic algorithm
There are two matters that shall be considered for the encryption of an HDD. One is the
encryption strength, specifically, the strength of the algorithms to be encrypted, key lengths,
and keys. The other is the mechanism of the key management.
There are schemes to confirm the encryption strength, such as to confirm whether the
cryptographic algorithm is correctly implemented or not. A cryptographic algorithm can be
confirmed with CMVP based on FIPS140-2 by NIST (National Institute of Standards and
Technology), and with “Japan Cryptographic Module Validation Program” by IPA. For example,
users can check with the evaluation criteria to confirm whether the encryption mechanisms for
the protected assets are validated under these schemes, or whether the implementation of the
cryptographic algorithm is reliable or not. The strength of the keys when generating them can
be verified using these schemes.
Supplement: Key management
For key management, keys would be stored eventually in plain text somewhere in the MFP,
even in cases when the keys are managed by encryption using another key. Where the plain text
key is stored, and how it is protected, become important. When the plain text key is stored in
the RAM, etc., the possibility of the leakage of protected assets still remains. An effective
means to store the key that should be kept confidential is believed to be the installation of a
19
20
For example, DriveTrust, etc. of Seagate has an encryption chip on its HDD.
http://www.seagate.com/docs/pdf/whitepaper/TP564_DriveTrust_Oct06.pdf
Later-mentioned vulnerabilities shall be considered related to the maintenance functions.
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TPM.21 The TPM has tamper-resistance, such as deleting the contents of the memory, when
someone is trying to gain unauthorized access to the internal memory of the TPM.
Supplement: Storage of protected assets on removable media such as USB memory
In cases when the protected assets are stored on a removable medium, such as USB memory, it
is desirable for users to ensure the security of the removable medium using the encryption
function that is similar to that of the HDD. For example, in the case of USB memory, protected
assets saved in USB memory when it is running are limited to the owner’s USB memory. There
is only a small chance of access by other users, but there is a strong possibility of losing the
USB memory. It is required for users, who perform the operations to store the protected assets
in the USB memory, to select the USB memory certified by CMVP or the “Japan Cryptographic
Module Validation Program” and to have the operational policies as described above.
7.3.4 [Causes and discussion]
The use of generic products causes the removal of storage media, such as HDDs, because it is
easy for attackers to visually recognize them. However, the removal of the products from the
MFP is performed the same way as for appliances and server products, and is not limited to the
MFP. Users shall take measures with such matters in their operations. Developers are required
to implement the protection using encryption so that the existing protected assets are
computationally secure and will not be read, and also to implement a proper management of the
information for decryption of the encrypted data. On that basis, it is important to implement the
necessary functions in response to the security level for the products by confirming measures
against changing of HDD as described above, or reading the key information from the RAM.
21
http://www.trustedcomputinggroup.org/developers/trusted_platform_module/
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7.3.5 Measures
[Operation guide]
1)
Enable the encryption function, or select the MFP that is implemented with the
function.
Execute the full-spectrum deletion function on disposal/return. (Select the MFP that is
implemented with the full-spectrum deletion function.)
Confirm the safety assurance of the keys and cryptographic algorithm used for
encryption.
The PIN code22 shall be appropriately managed in cases when the private keys are
protected by the TPM, etc.
In cases when USB memory is used for protected assets storage, for example, select the
certified products under CMVP or “Japan Cryptographic Module Validation
Program.”23
2)
3)
4)
5)
[Development guide]
6)
7)
Implement the full-spectrum encryption function on the HDD.
Implement with the full-spectrum overwrite deletion function for the storage area with
protected assets in the MFP.
Implement (select) the mechanism of encryption that ensures safety.
Implement the validation function to detect unauthorized replacement for replaceable
parts, such as HDDs, etc.
8)
9)
[Verification guide]
10)
11)
In cases when the HDD encrypted protection is evaluated, confirm the strength of the
cryptographic algorithm and private keys, methods to generate keys, and the safety of
the storage location.
If there is no verification on the HDD, confirm the input of code, etc. to decrypt the
decryption keys of the HDD or their strength.
7.3.6 References
Date of publication
March 2009
Source
Unlocking of HDD passwords
http://homepage3.nifty.com/3gatudo/hddlock.htm#hdd
Article about HDD locking passwords can be reset with the DOS tool that is published
July 2008
Defeating Encrypted and Deniable File Systems: TrueCrypt v5.1a and the Case of the Tattling OS and
Applications
http://www.cs.washington.edu/research/security/truecrypt.pdf
Examples of the existence of vulnerabilities in the encryption for only some limited area of the HDD
CRYPTOGRAPHIC MODULE VALIDATION PROGRAM (CMVP)
http://csrc.nist.gov/groups/STM/cmvp/index.html
Description of CMVP based on FIPS140-2 in North America
Japan Cryptographic Module Validation Program (JCMVP®)
http://www.ipa.go.jp/security/jcmvp/index.html
Description of “Japan Cryptographic Module Validation Program,” by IPA
May 2012
August 2012
April 2009
Risk of hibernation
http://www.st.rim.or.jp/~shio/winsec/hibernation/
Description of the risk related to handling data that is deployed on the HDD during hibernation
A personal identification number that consists of several digits. PIN refers to Personal Identification
Number.
23 The certified products are listed in MODULE VALIDATION LISTS
(http://csrc.nist.gov/groups/STM/cmvp/validation.html), and in Cryptographic Module Validation List
(http://www.ipa.go.jp/security/jcmvp/val.html), respectively.
22
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7.3.7 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
As a worst case scenario, MFPs that are stored on the HDD, where the protected assets
containing configuration information are not encrypted, will be discussed. A removed HDD can
be mounted easily on a PC equipped with a general-purpose OS in some cases, but the
following is assumed for scoring:
- An attacker has the same type of MFP that he/she is attacking.
- Protected assets on the HDD are not deleted.
- The MFP is physically accessible.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
6.6 (Warning)
Exploitable locally only
Low
No authentication operation required
Overall impact
No impact
Overall impact
[Attack assumptions]
The attack discussed next is the leakage of protected assets that are stored on the HDD; as
described above in the attack methods. It is caused by changing the encrypted HDD and
collecting data from it after a certain period of time. In this case, again, an attacker possesses
the same type of MFP that shall be used with the following assumptions:
- The MFP is physically accessible.
- Protected assets on the HDD are not deleted.
- The input of decryption keys of the HDD is open to users.
- The identification verification function of the HDD is not implemented on the MFP.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
4.4 (Warning)
Exploitable locally only
Moderate
No authentication operation required
Partial impact
Partial impact
Partial impact
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7.4
Information leakage caused by equipped SSD
Traditionally, the MFP has a built-in HDD as a large capacity storage medium to store protected
assets. Most MFPs take measures against the leakage of protected assets in such ways as by
overwrite deletion of data and encryption, as described in Section 7.3, because of the risks of
removal of HDDs by third parties or users, and the property that the deleted data is easily
recovered.7.3
In recent years, the HDD has been replaced by the SSD for the higher-speed data access and the
reduction of failure rate. Some MFPs have both a built-in HDD and SSD, and only the data that
requires high-speed access is stored on the SSD. In either case, measures, such as SSD
encryption or data deletion, are required as long as protected assets are stored on the SSD.
7.4.1 [Special features of SSD]
For the purpose of description, the SSD is defined in this report as shown in Figure 7-2,
“Relationship between logical blocks and physical blocks.”
SSD
Physical page
Physical blocks
Logical blocks
Users
:
Controller
・・・
Physical ⇔ Logical
Mapping
Figure 7-2 Relationship between logical blocks and physical blocks
The storage area of the SSD is divided into block/page unit. While the logic blocks are for users
to access, the physical blocks are supported by the controller. Therefore, users cannot be aware
of the physical area so that it is impossible to access any physical area. The supports vary
depending on circumstances of the physical area. This is done in order to prevent only part of
the blocks/pages from reaching the upper limit of the number of rewrites, which is a defect of
the SSD, and is referred to as wear leveling function. In fact, the upper limit is a hundred
thousand rewrites on the SLC chip, and ten thousand rewrites on the MLC chip of the SSD.
Taking into account the possibility that the SSD may be removed, the temporary saved data can
be deleted in a manner similar to that used for HDDs by overwriting 3 times using the Pentagon
method (DoD5220.22-M), or 35 times using the Gutmann method. In addition, it is extremely
difficult to implement the overwrite deletion function of any physical area by block/page unit
due to the wear leveling function as mentioned above.
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7.4.2 [Attack methods and measures]
The removal of the SSD from the operating MFP, and the removal of the SSD from the
disposed MFP or returned MFP are considered as attacks, as with the case of HDD.
As described above, it is difficult to implement the overwrite deletion function of any physical
block/page unit due to the properties of the SSD. There is a strong possibility that the overwrite
deletion function for temporary stored data is not implemented. On the other hand, the SSD
built into the MFP is visually identifiable, and it can be confirmed that some MFPs are
connected with standard connectors. In this case, it is possible to remove the SSD if the main
unit of the MFP is accessible. Data encryption of the SSD is effective as a preventive measure
against information leakage due to the SSD removal.
It is also effective to implement a full-spectrum overwrite deletion function in addition to the
encryption against the leakage of protected assets at the time of disposal or return of the MFP.
The physical area of an SSD cannot be accessed, but the SSD controller may be implemented
with the full-spectrum deletion without being affected by the wear leveling function, because
the SSD controller is implemented with the function to release (reset) the charge of all the
physical areas and to reset it to the factory settings.
However, it has been reported that the function to release (reset) the charge to the controller is
implemented by mistake in some SSDs.24 If MFP vendors implement the full-spectrum
deletion function, the selection of an appropriate SSD shall be considered as well.
As a feasible implementation of the MFP functions, encrypting of the SSD and resetting of the
physical area at the time of MFP disposal or return are considered to be effective.
Supplement: Attackers’ viewpoints
The property that any SSD physical blocks/pages are not accessible makes it difficult even for
attackers to attack the data stored on the SSD. High technology is required to recover from the
excess blocks some data that is logically deleted without using the overwrite deletion method,
etc. (i.e., data on the excess blocks not visible via controller, even if it remains on the page
physically), by accessing the physical pages/blocks bypassing the controller.
7.4.3 [Discussion]
One of the purposes for equipping the MFP with an SSD is to improve the access speed to the
data, including protected assets. If this purpose is thought to be of great importance, the
encryption that is an effective means of countermeasure may not be implemented in some cases.
For the data on the excess blocks that remains due to the removal of logical data, it is said that
high technology is needed to attack, so that no problems may occur. However, the data on the
block that is supported logically and the data on the SSD that is not deleted can be accessed, as
with the case of the data on the HDD. In cases when protected assets are stored on the SSD, the
developers of the MFP vendors are required to use the encryption function when storing the
data on the SSD.
24
A team from the University of California, San Diego, reported at the 9th USENIX Conference on File and
Storage Technologies in February 2011.
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7.4.4 Measures
[Operation guide]
1)
In cases when protected assets are stored on the SSD, enable the encryption function,
or select the MFP that is implemented with the function.
In cases when protected assets are stored on the SSD, enable the full-spectrum deletion
function on disposal/return, or select the MFP that is implemented with the function.
Confirm the safety assurance of the keys and cryptographic algorithm used for
encryption.
2)
3)
[Development guide]
4)
5)
6)
7)
8)
If the SSD and the HDD are used together, confidential information is assumed not to
be stored on the SSD.
Implement the encryption function on the SSD.
Implement the full-spectrum deletion function on the SSD.
Select an SSD on which a full-spectrum encryption function is implemented correctly.
Implement (select) the mechanism of encryption that ensures safety.
* If the measure 4) is taken, other measures are not necessary.
[Verification guide]
9)
By understanding the properties of the SSD, the verification shall be performed in
accordance with the properties of the SSD. Attack potentials against excess blocks are
always rated based on the latest information. In cases when attacks are possible, it is
verified that the functions that the MFP is implemented with can be countered.
7.4.5 References
Date of publication
February 2011
Source
Reliably Erasing Data From Flash-Based Solid State Drives
http://static.usenix.org/events/fast11/tech/full_papers/Wei.pdf
Report of the SSD that is inappropriately implemented with the reset function
2011
NPO Institute of Digital Forensics Research Column
http://www.digitalforensic.jp/expanel/diarypro/diary.cgi? no=399&continue=on
Article on flash memory forensics
Article on ITmedia Enterprise
http://www.itmedia.co.jp/enterprise/articles/1107/16/news001.html
Article on the means of data protection on the SSD
Intel SSD optimizer website
http://www.intel.com/jp/consumer/Shop/diy/features/ssd/optimizer/p1.htm
Article of special features of the SSD
July 2011
N/A
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7.4.6 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
Attacks by accessing the protected assets on the SSD built into the operating MFP are discussed
here. It is assumed that the SSD is removed from the MFP in the same way as in the attack to
the HDD. However, the scoring greatly differs between the protected assets that are in the
excess block and are not logically supported, and other protected assets, due to the properties of
the SSD (while the scoring for both types of protected assets is the same for the HDD). In this
section, considering the properties of the SSD, the impact on confidentiality is assumed to be
partial.
- An attacker has the same type of MFP that he/she is attacking.
- The MFP is physically accessible.
- The encryption function is not implemented on the SSD.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
5.4 (Warning)
Exploitable locally only
Low
No authentication operation required
Partial impact
No impact
Overall impact
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7.5
Problems of access to local maintenance interfaces
There are maintenance interfaces in the MFP other than interfaces that can be accessed by users
(general users and administrators, etc.). Maintenance interfaces are also categorized by local
maintenance interfaces that are directly operated by the maintenance personnel at the main unit
of the MFP, and the remote maintenance interfaces that are operated remotely by using http and
other protocols. Vulnerabilities on the local maintenance interfaces are discussed in this section,
in the light of information that has been published in recent years.25
7.5.1 [Functions of the local maintenance interfaces]
Main functions that are operable from the local maintenance interfaces are as follows:
- Checking toner and checking/resetting counter
- Settings (restrictions)/initialization of the MFP functions
- Settings/initialization of the administrator passwords
- Fine adjustments of the MFP functions and operations
If an attacker exploits the functions that can be manipulated from the maintenance interfaces, it
is possible even for non-maintenance personnel to initialize the settings of the administrators,
change users’ authentication data as an administrator, and view and manipulate the protected
assets. If the MFP is leased/rented and charges a fee, the billing information can be modified by
changing the counter. In many MFPs, therefore, local maintenance interfaces are protected by
means of special confidential operations and authentication with strong passwords, or by one of
those.
7.5.2 [Attack methods and the impacts]
Some MFPs have special confidential operations as the means of protection for the local
maintenance interfaces. Considering the costs of maintenance personnel, it is less likely that the
operating procedures would vary by each MFP, and the same specific procedure may be applied
by the product type or model number of vendors in some cases. In this case, the major
assumption is that there will be no leakage of the operating procedures.
However, in fact, the special operating procedures used to access the maintenance interfaces of
some MFPs (key operations by the operation panel of the MFP) have been published on some
Q&A sites overseas, etc., and the actual MFP maintenance interfaces may be accessible by
following the procedures published. That is to say, protections by the specific operation
procedures will be lost at the point that those procedures were published. Besides, if an attacker
uses such public information to contact the MFP, the attack would be extremely easy.
25
Attacks by exploiting the firmware update function of the maintenance interfaces are described in
Section 7.7, and web-based maintenance interfaces using the http protocol are described in Section 7.16.
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1. The "TECH MODE" of the model name / model name
According to official sources from vender name, the brother of model name, the in the same way
constructed model name, has a so-called “Tech Mode”, where a service technician (or you!) can do
some tests or adjust some additional settings.
1.1. Entering and leaving the "TECH MODE"
To enter the TECH MODE (or to leave it) ...
1.
2.
Press the
key
on the keypad quickly enter
If the menu / display is configured to use a language different from English (e.g. German, French...)
the display will change to the English language (Ready instead of Bereit etc.). There will also be a
clock displayed instead of the zoom percentage values. In the end the display will look similar to this:
Ready
14: 32
TECH
To leave the TECH MODE just repeat the above mentioned procedure or just wait a moment, as the
model name will leave TECH MODE automatically after some time. You will recognise this by the
absence of TECH MODE in the display. If you normally use a different language for the display, the
display will revert to the configured language after leaving TECH MODE.
Figure 7-3 Publicly available operations for entering maintenance mode
7.5.3 [Causes and discussion]
The direct cause of the attacks discussed in this section is that the procedures for access to the
maintenance interfaces have been published. However, a fundamental problem lies in the
implementation in that the means of protection of the maintenance interface relies on the “fixed
key operation” that can be operated with administrator privileges as well. Maintenance
interfaces require the same protection of passwords that are equivalent to the user interfaces as
well as administrator interfaces.
It is unlikely, in a general sense, that multiple MFPs controlled by one maintenance person are
managed with all different passwords. If a certain number of MFPs are managed by the same
password, and the password is not updated, it is extremely vulnerable if such password is
published as well as the above-mentioned specific operation procedures. It is confirmed from
research that the input information considered to be passwords has actually been published in
some cases.
To counter these vulnerabilities, the ideal operations are to use different passwords to access
maintenance interfaces of each MFP. In addition, it is desirable to protect the MFP with
stronger passwords than users’ and administrators’. In cases when the same passwords or
regular passwords are used for a certain number of MFPs, persons who know the special
operating procedures and passwords (such as maintenance personnel) shall be specified. For
perfect management, non-disclosure agreements, which would be effective on a permanent
basis, and educational activities, etc., would be necessary. In addition, to limit the persons who
have physical accessibility to the MFP to only personnel who can control could be a general
measure against the leakage and tampering of the protected assets by external attackers. Even in
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the case of having access restrictions, it is impossible to prevent attacks by authorized users
who have physical access to the MFP.
Supplement: Examination of initial passwords
The vulnerabilities due to putting back factory settings that are similar to the attack technique
against vulnerabilities described in this section are described in Section 7.6. The passwords of
the maintenance interfaces may be reset to the fixed initial passwords by taking advantage of
these vulnerabilities, even if the passwords are protected.
Supplement: Hidden interface
There may be other confidential “hidden interfaces” than the maintenance interfaces described
in this section. For example, there would be interfaces that provide functions to confirm the
contents of the memory and the specific access methods to the embedded OS which is installed
for failure handling and debugging. It may require special handling that even maintenance
personnel are not aware of, or connection to a special connector installed inside the MFP. In
comparison to the maintenance interfaces that are described in this section, the risk that its
existence and access procedures of the special interfaces only known to some developers are
published, may be low. Developers shall still protect these interfaces assuming threats,
including leakage, similar to those of the maintenance interfaces.26
7.5.4 Measures
[Operation guide]
1)
The MFP that handles protected assets shall be checked with the protection mechanism
of the maintenance interfaces at the time of selecting the MFP.
[Development guide]
2)
3)
4)
The authentication strength of the maintenance interfaces shall be stronger than the one
for users or administrators.
Hidden interfaces shall also be protected against the assumed threats.
For the maintenance interfaces and the hidden interfaces, a mechanism that does not
use the same operations and passwords among multiple products shall be
implemented.
[Verification guide]
5)
6)
The presence of interfaces and the fact that the operation procedures are confidential
shall not be the security grounds.
Verify that the authentication strength of the maintenance interfaces is sufficient. In
such case, the uniqueness and predictability of passwords shall be considered.
7.5.5 References
* Information is omitted in this section in consideration of the exploitation.
26
An implementation, such that the debug screen is displayed on the user interfaces when an exception
occurs, shall not be performed for security reasons.
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7.5.6 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
The cases when a user attacks by using the access procedure to the local maintenance interfaces
are assumed (obtaining protected assets of other users and administrators, or tampering with the
counters related to billing, etc.).
- It shall be the model that does not take the above measures in the Development guide.
- The procedure for accessing the maintenance interfaces has been published.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
Requirement
Confidentiality
Integrity
Availability
7.2 (Danger)
Exploitable locally only
Low
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.6
Problems of resetting to the factory settings
Even for MFPs that handle protected assets, such as those based on the assumptions described
in this report, there is a tendency in a factory default condition for convenience to be given
priority, so the security of the protected assets is not considered in some cases. The convenience
here refers to the conditions, namely, the use of the communications protocol described in
Section 7.11 not being limited to the minimum, or strong passwords for users or administrators,
etc., not being set up. Password settings of the factory settings may be also initialized to access
the maintenance interfaces.
7.6.1 [Attack methods and the impacts]
Attack by tampering with the settings of the MFP by resetting to the factory default settings is
discussed. The following scenario can be considered as attacks against the integrity and
confidentiality of the protected assets:
1)
2)
3)
4)
Figure out the basic configuration information of the MFP and the registered user IDs,
etc.
Reset the MFP to the factory settings.
An attacker resets the basic configuration information to create a user account by
impersonating an administrator.
Then, the attacker obtains the protected assets of each user stored in the MFP.
The basic configuration information of the above procedure 1) is the information that users
usually know, such as IP addresses assigned to the MFP, etc. User IDs, etc., are the information
that users, who can be attackers, can guess by checking the user IDs of others registered with
the MFP. In addition to the integrity and the confidentiality of those assets, the availability of
the protected assets will be lost at the time the configuration is reset to the factory settings.
Taking those into consideration, it is required that users cannot reset to the factory settings by
themselves for the MFPs whose factory settings are not secure. In other words, a mechanism to
protect the procedures to reset to the factory settings should be equivalent to, or stronger than,
the authentication for users and administrators, or a mechanism to access the maintenance
interfaces.
However, in reality, there are cases when users can reset to the factory settings using the special
operation procedures in some MFPs. For example, information as shown in Figure 7-4 has been
published.
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You can also reset the NVRAM. Resetting the NVRAM will clear the page count and reset the
service mode settings to factory defaults. On printers with a display panel you need to enter
service mode to manually change the information stored in NVRAM. On printers that don't have
a display panel, such as a model name there is a different procedure outlined below.
"Older" printers with a display panel. (e.g.model name, etc.)
Cold resetting the printer is simply a matter of
, holding down the
O
while turning the printer on.
Resetting NVRAM settings should be done manually in service mode. See entering service mode.
"Newer" printers with a display panel. (e.g. model nameetc.)
Turn the printer off and then on. When the printer begins its memory count, press and hold down
the
and
. Then
release the
, and use the
to find the Cold Reset option,
then press the
to choose that option.
Figure 7-4 Published procedures for putting back the factory settings (overseas MFPs)
7.6.2 [Causes and discussion]
In such cases, even if the procedures that should be confidential have been published, they are
not regarded as an attack method leading to information leakage, because the function to reset
to the factory settings is considered to be one of the maintenance functions with the impact of
clearing the settings and protected assets. However, in reality, once the attack is performed as
described above, the risks are no longer overlooked, as the protected assets stored in the MFP
afterwards would be exposed to attackers.
The general measure to this vulnerability is to disable the functions for users and for third
parties to reset to the factory settings by making the authentication and usage restrictions more
robust as with the case of the maintenance interfaces. For example, this measure could be easily
realized only from the menu after connecting from the maintenance interfaces, by installing the
function to reset to the factory settings. The assumption is that the maintenance interfaces are
strongly protected.
As a countermeasure to reduce the impact when it is reset to the factory settings is to make the
settings secure. This security by default performs only minimum services in the initial state, and
such services shall be limited to the secure range of usage. The risk management of the
operational side is given weight to expand the settings such that services are operated as
necessary. This idea has an advantage in case things will turn out to be secure even if there is a
configuration information leakage during the MFP installation.
Supplement: Status display
For the MFP that is assumed to be used in a secure environment, it is desirable to be secure by
default. There may be some MFPs that are shipped with the general services activated for the
convenience of users, in addition to usage in a secure environment. It is desirable that such
MFPs be implemented with functions that enable users to identify the security status at a glance.
It is also desirable that such MFPs are implemented with functions that can identify the settings
status, such as the time of resetting to the factory settings, regardless of being secure by default.
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7.6.3 Measures
[Operation guide]
1)
2)
An MFP that handles protected assets shall be checked with the function to reset to the
factory settings at the time of selecting the MFP.
Make sure that the MFP is set to a secure state when using it.
[Development guide]
3)
4)
5)
6)
Place the function to reset to the factory settings in the menu of the maintenance
function, to establish a strong proprietary authentication mechanism.
When implementing a proprietary authentication mechanism, the mechanism that does
not use the same operations and passwords for multiple products shall be implemented.
If the MFP can be in a non-secure state by its settings, a mechanism by which users can
identify the current security status shall be implemented.
Apply the concept of security by default for the MFPs that are assumed to be used in
security-conscious environments.
[Verification guide]
7)
8)
Confirm that the authentication strength is sufficient until a function to reset to the
factory settings is performed. In such case, the uniqueness and predictability of
passwords shall also be considered.
Operate and examine all settings items that have an impact on security status by
checking the indicator to determine if the security status and the actual MFP status do
not differ from each other.
7.6.4 References
* Information is omitted in this section in consideration of the exploitation.
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7.6.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
As described in the attack methods of this section, the attacks by unauthorized access against
the protected assets that are stored after the attackers reset the MFP in accordance with the user
environment, after resetting the factory settings from the operation panel of the MFP, are
discussed here.
- It shall be the model that does not take the above measures in the development guide.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
5.9 (Warning)
Exploitable locally only
Moderate
No authentication operation required
Partial impact
Partial impact
Overall impact
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7.7
Problems from exploiting the firmware update function
The MFP with the maintenance interfaces that provide maintenance functions via the intranet or
external networks has a firmware update function in many cases as part of the maintenance
functions. By using the firmware update function to update the unauthorized firmware and to
operate the firmware, it is possible to induce unauthorized operations of the MFP and access to
the protected assets.
In the article published in November 2011, the professors from Columbia University
demonstrated that, it is possible to overheat the fixing roller of the MFP by exploiting the
firmware update function and operating the unauthorized programs. Details of the attack
methods presented in the article are described as follows:
7.7.1 [Attack methods and the impacts]
Step 1. Confirmation of the firmware updates
The procedures for firmware update vary depending on MFP models and vendors, but some
MFP firmware updates have been published. Therefore, firmware updates are performed easily
by following these procedures. For example, if keywords such as “remote firmware update LPR
command” are used for search, the procedures for firmware update using the LPR can be found.
Remote firmware update by using the LPR command
NOTE:
This remote firmware update method is for use in Windows 2000 Service Pack 3, Windows XP,
Windows Server 2003, and Windows Server 2008.
Complete the following steps to update the firmware by using the LPR command.
1. From a command window, type the following:
lpr -P -S -o l
OR
lpr -S -Pbinps
where IPADDRESS can be either the TCP/IP address or the hostname of the product, and where FILENAME
is the filename of the .RFU file.
NOTE:
The parameter (-o l) consists of a lowercase “O”, not a zero, and a lowercase “L”, not the
numeral 1. This parameter sets the transport protocol to binary mode.
2. Press Enter on the keyboard. The messages described in the section Printer messages during the firmware
update appear on the control panel.
3. The download process begins and the firmware is updated on the product. This can take several minutes.
Figure 7-5 Excerpt from the firmware update by using the LPR command
Step 2. Confirmation of the official firmware updates
First of all, official firmware should be prepared. Try to obtain the official firmware, suitable
for the devices that can be attacked, from the links on the pages that are found above, or with
the keywords such as “[vendor name] [model name] firmware download.”
Once the firmware is obtained, binary data of the firmware can be modified to create
unauthorized firmware.
For example, the later-mentioned “7.7.4 References: PRINT ME IF YOU DARE - Firmware
update attack and the rise of printer malware -” introduces the binary information of the
firmware, and they are the lists of the PJL commands in which their meaning can be read.
Firmware is found out to be the 7M data according to the description of “@PJL UPGRADE
SIZE=792990,” and there is a description of the actual firmware data at the end of the “@PJL
ENTER LANGUAGE=ACL <CR> <LF>.” ACL stands for Advanced control language, and is
a language used for the MFP firmware description. The important thing here is that the
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firmware part has not been encrypted and is only being compressed. This indicates that
firmware can be created as long as the syntax is figured out.
Step 3. Confirmation of the verification function of the MFP firmware
Most of the current MFPs have a function to verify the validity of files, using the encryption
technology called electronic signature. The verification using an electronic signature creates
private keys and signatures from the hash value of the firmware to confirm that the hash value
uploaded to the MFP and the hash value created from the signatures are the same. Therefore,
when an attacker who does not know the private keys tries to create unauthorized firmware,
electronic signatures that can pass validation cannot be created due to the property that the hash
values of the digital signature do not collide.
Some MFPs do not use the encryption technology, but perform only verification by the CRC
check, etc. In fact, the following information was published as a guidance as of May 2012. In
this model, firmware files can be uploaded once the CRC check is cleared because there is no
other description of firmware errors found.
Control panel message
CODE CRC ERROR
Description
An error has occurred during a firmware
upgrade.
Recommended action
1. Reinstall the firmware.
2. If the problem persists, contact
Vendor name Support.
Figure 7-6 Public information of the firmware verification methods
Step 4. Confirmation of the unauthorized firmware
Up to Step 3, the method for uploading arbitrary firmware impersonating official firmware to
the MFP is confirmed. After that step, if the firmware with arbitrary code embedded is created,
it is possible to induce unauthorized behavior on the MFP and access to the protected assets by
using some maintenance interfaces of the MFP. In the article, the reverse-engineering of the
binary assembly was performed to understand the syntax by building different hardware, and
the attack was successful. In addition to the costs for building hardware and debugging
environments to analyze the MFP as a target of attack, several technologies, such as
reverse-engineering or electrical circuits, may be required. If someone publishes the specific
unauthorized MFP firmware, attacks can be conducted by using it.
The article claims that the fixing roller of the MFP can continue to be heated up using the
unauthorized firmware.
Supplement: Developers’ viewpoints
The MFP vendors who have pointed out the above problems have published on their websites
about their thermal breakers designed to prevent overheating of the fixing roller, so they claim
that there would be no problem. However, they do not deny possible unauthorized firmware
rewriting, and commented that there would be no problem as long as the MFP is not connected
to an external network without a firewall. This does not deny the possibility of findings that the
vulnerabilities have an impact on the attacks from the internal networks where attackers are
present.
All of the necessary ports for rewriting the firmware are not necessarily open, but many MFP
web interfaces are published and can be found by searching in SHODAN or Google as of May
2012, which confirms that external access is possible.
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7.7.2 [Causes and discussion]
The problem for the MFP is that the unauthorized firmware can be uploaded. The reasons are
that the firmware upload function using the maintenance interface function only performs
integrity checking of firmware data by CRC, and the binary of firmware to be updated is not
encrypted. As described in the comments by the vendors in the supplement, the
implementations that are described here may be sufficient if it is assumed that the maintenance
interfaces that access from the internal networks cannot connect from the outside and all the
users on the internal networks are reliable. For usage in real situations, however, it is desirable
that the maintenance interfaces are robust enough against attacks from outside, because they are
connected externally (via telephone line and WebDAV servers other than Ethernet). In cases
when the encryption of the firmware to be updated is applied, it is necessary to consider the key
management and cryptographic algorithms, as described in Section 7.3.3.
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7.7.3 Measures
[Operation guide]
1)
2)
3)
Terminate the maintenance interface via network, if it is not needed.
Use the MFP equipped with a strong verification function (electronic signature, etc.)
for the firmware binary data that is updated.
Use the MFP equipped with an encryption function that uses secure algorithms for the
firmware binary data that is updated.
* It is effective to terminate the maintenance interfaces via networks as a solution, but it
would lose the convenience which is the original purpose of using the MFP. The selection
of the devices that are implemented with the validation function by electronic signatures or
encryption of firmware binary data, etc., could be the realistic measures. It is desirable to
make it a condition to select MFPs that are implemented either with encryption or strong
correctness verification.
[Development guide]
4)
5)
Provide a strong verification function (electronic signature, etc.) for the firmware
binary data that is updated.
Provide an encryption function with secure algorithms for the firmware binary data to
be updated. (Private keys used for encryption shall be securely managed).
* It is desirable to implement strong correctness verification in consideration of the
availability of the MFP.
[Verification guide]
6)
7)
Confirm that the correctness verification function of the firmware binary data is not
exploited by assumed attackers.
Confirm that the encryption function of the firmware binary data is appropriately
implemented with a secure specification, and that the operation of the encryption
function is a secure procedure, from the security perspectives in specifications, designs,
development environments, and delivery/installation (including updating procedures).
(It is also necessary to confirm that private keys are not leaked.)
7.7.4 References
Date of publication
November 2011
December 2011
December 2011
Source
Exclusive: Millions of printers open to devastating hack attack, researchers say
http://redtape.msnbc.msn.com/_news/2011/11/29/9076395-exclusive-millions-of-printers-open-to-dev
astating-hack-attack-researchers-say
Article about the vulnerabilities using the maintenance interfaces of the MFP, published by the
professors from Columbia University
CVE-2011-4161
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2011-4161
The vulnerability information on the firmware update function of some MFPs of HP
PRINT ME IF YOU DARE - Firmware update attack and the rise of printer malware http://ids.cs.columbia.edu/sites/default/files/CuiPrintMeIfYouDare.pdf
Materials describing the attack procedures published by the professors from Columbia University
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7.7.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
This section limits attacks to those from neighboring networks as an attack category. In cases of
security-conscious environments, update functions using the fax line are assumed to be
dysfunctional, and the communications is controlled externally, such by a firewall. The
following are assumptions:
- The firmware update function can be accessed without authentication.
- It shall be the model that does not take the above measures in the Development guide.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
* It will be 8.3 (Danger) when unauthorized firmware is
published.
7.9 (Danger)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.8
Problems due to vulnerabilities of the embedded OS
Conveniently, quite a lot of MFP vendors have chosen the open-source embedded Linux
(MontaVista, Wind River, Timesys, Denx etc.) in recent years because of the OS price and the
convenience of development by open-source and the convenience of being able to add some
functions. On the other hand, such introductions of multi-function built-in OS’s can cause the
security defects embedded in the MFP in some cases. Specifically the following: Risks of
vulnerabilities of the development language functions such as buffer overflow that may be
inherited from the results of development by the cross compiler on the PC, abuse of the services
for remote operations by default (NFS, Tftpboot, Gdbserver, etc.), the possibility of leakage of,
and tampering with, protected assets by taking advantage of the vulnerabilities of the embedded
Linux or various installed applications and the possibility that the MFP will not work properly
due to denial-of-service attack.
In this section, risks from the vulnerabilities of the embedded Linux or various applications that
are installed, and the problems of usage under the default settings are pointed out.
7.8.1 [Attack methods and the impacts]
MontaVista has published widely the vulnerability information of their products on the website
shown in the references. According to this vulnerability information, four vulnerabilities of
MontaVista Linux (except for the Carrier Grade Edition) have been reported as of October 2012
as follows:
Table 7-1 Examples of vulnerabilities of the embedded Linux
Explanation27
CVE
CVE-2012-1165
(JVNDB-2012-001801)
CVE-2012-0884
(JVNDB-2012-001735)
CVE-2012-0814
(JVNDB-2012-001739)
CVE-2012-0021
(JVNDB-2011-003659)
The mime_param_cmpfunction in crypto/asn1/asn_mime.c of
OpenSSL has vulnerabilities of becoming denial-of-service
(NULL pointer dereference and application crash).
Vulnerability that the data to be decrypted readily exists,
because the implementation of the PKCS #7 and Cryptographic
Message Syntax (CMS) of OpenSSL does not properly restrict
specific operations.
Vulnerability exists that the important information is obtained,
because the auth_parse_options function of auth-options.c in the
sshd of OpenSSH outputs debug messages, containing
authorized_keys command options.
When the threaded MPM is used, vulnerability to be denial-ofservice (daemon crash) exists because log_cookie function in
mod_log_config.c located in the mod_log_config module of the
Apache HTTP Server does not properly handle the character
strings of %{}C format.
Above-mentioned CVE-2012-1165 and CVE-2012-0884 are the vulnerabilities related to the
implementations of OpenSSL that are provided (supported) together with the embedded Linux
(MontaVista Linux). In cases when the MFP introduced the embedded Linux has been used
with the above-mentioned vulnerabilities left untouched, possible denial-of-service attacks as
well as wiretapping of the communications data, etc., between the MFP and the client terminals,
etc., may be performed.
In Wind River Linux, five vulnerabilities in version 3.1 and four vulnerabilities in version 3.0
are found in SecurityFocus due to the vulnerabilities of mainly Linux kernel. (Details are
27
Excerpts of the vulnerability information from JVN iPedia (http://jvndb.jvn.jp)
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described in the reference information.). By exploiting these vulnerabilities, there are
possibilities that unauthorized access to the protected assets may be performed or that the MFP
will not operate properly by the denial-of-service attacks.
In addition to the risks due to the vulnerabilities of the embedded Linux as described above,
there may be possibilities that unnecessary network services are running on the MFP when the
embedded Linux has been used by default settings without using the security settings, etc. In
cases when there are vulnerabilities in the implementation of unnecessary network services, or
appropriate security settings for the encryption and identity authentication, etc., are not
performed, there are possibilities that the various risks on the information security, such as the
leakage or tampering by unauthorized access to the protected assets, may occur.
Additionally, when the MFP starts up, it is confirmed that some models display the information
about the OS, etc., on the panel. In cases such information (banner information) is exploited,
there are possibilities that unauthorized access to the protected assets and information leaks, etc.,
may occur due to the attacks against vulnerabilities of the OS, etc.
7.8.2 [Causes and discussion]
In recent years, the embedded Linux has been introduced in a number of MFPs, because of low
costs and its convenience of development that is the benefits of open source. While it has these
benefits, there are possibilities that various risks to information security may occur, such as the
leakage and tampering of the protected assets stored in the MFP by unauthorized access by
attackers who exploit unnecessary services and the vulnerabilities of the applications that run
on the MFP or on the embedded Linux.
To respond to the above-mentioned risks, developers need to take measures, such as applying
security patches (or providing notifications and distributions to the users) as necessary
according to the vulnerability information about the embedded OS (Linux) that has been
introduced. In addition, because unnecessary services are possibly running, it is desirable to
check the operation status and the vulnerabilities of the implementation using port scanners or
vulnerability scanner, etc., before the product is released, as with the case of general Linux
servers, etc.
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7.8.3 Measures
[Operation guide]
1)
The methods of applying security patches, etc., and the vulnerability information of the
embedded OSs and applications that have been introduced to the MFP shall be
confirmed with the MFP vendors.
[Development guide]
2)
3)
4)
5)
6)
Thorough observations on the coding provisions that do not bring language
vulnerabilities (buffer overflow, etc.) in the cross-compile environment shall be made.
Vulnerabilities of an embedded OS and the applications that run on it shall be
confirmed, and if necessary, security patches shall be applied, or the function to
counter vulnerability shall be implemented.
Check that unnecessary services, or the services whose vulnerabilities have been
published, are not running, by using the system configuration information, the port
scanners, or vulnerability scanners, etc., and terminate or delete such services as
necessary.
Implement in such a manner that banner information of the OS or application (module)
version that is running will only be presented when necessary.
Explain specifically the vulnerability information and applications of the security
patches, etc., to users in the guidelines, etc.
[Verification guide]
7)
8)
9)
Examine the presence or absence of vulnerabilities of the embedded OS and the
applications that run on it, and whether they are executable or not.
Verify that unnecessary services, or the services whose vulnerabilities have been
published, are not running, by using the system configuration information, the port
scanners, or vulnerability scanners, etc.
Ensure that the means of notification of vulnerability information and applications of
the security patches, etc., are clearly described in the users’ guidelines, etc.
7.8.4 References
Date of publication
Frequently updated
Frequently updated
Source
CVE Vulnerabilities List (MontaVista)
http://www.mvista.com/cve_vulnerabilities.php
Vulnerability information (CVE: Common Vulnerabilities and Exposures) of the products provided by
MontaVista has been widely published
SecurityFocus
http://www.securityfocus.com/
Website of vulnerability information on products provided by various vendors
December 2009
Linux e1000 Driver 'Jumbo Frame' Handling Remote Security Bypass Vulnerability
http://www.securityfocus.com/bid/37519
Examples of vulnerabilities related to Wind River Linux (circumvention of security functions)
March 2010
Linux Kernel Bluetooth Sysfs File Local Privilege Escalation Vulnerability
http://www.securityfocus.com/bid/38898
Examples of vulnerabilities related to Wind River Linux (privilege escalation, denial-of-service attack)
January 2010
Linux Kernel 'ipv6_hop_jumbo()' Remote Denial-of-Service Vulnerability
http://www.securityfocus.com/bid/37810
Examples of vulnerabilities related to Wind River Linux (denial-of-service attack)
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7.8.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
A case is assumed that there are vulnerabilities that allow the embedded Linux to execute
arbitrary code remotely (internal LAN), and the attack tools have been published, which invoke
the shell that can take advantage of an OS administrator command of the MFP by using the
vulnerability.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
Requirement
Confidentiality
Integrity
Availability
8.3 (Danger)
Possible attacks from neighboring
networks
Low
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.9
Vulnerability related to SDK (Software Development Kit)
The SDK, described in this section, refers to the development environment of the applications
that can be installed on the main unit of the MFP for enhancement of the MFP functions. For
example, it is intended to customize user interfaces of the MFP operation panel that are attached
to the MFP for the users’ ease-of-use suitable for the usage environment. In addition to the user
interfaces, the SDK has the following functions:
- Copying, printing and scanning
- Device configuration management and job management
- Network settings
- File and folder (box) operations, etc.
As mentioned above, functions equivalent to the built-in functions for users by default on the
MFP can be used from the applications developed with the SDK. This indicates that the
protected assets can be accessed by using the applications developed with the SDK. Therefore,
among the applications developed by users using the SDK, only those applications, which are
determined by the developers of the MFP vendors that they do not reduce the security functions
of the main unit of MFP, can be added with the electronic signature by encrypting. Users install
the files that are signed and encrypted by the developers of the MFP vendor onto the MFP. At
that time, the main unit of the MFP verifies the signatures, and decrypts them.
7.9.1 [Attack methods and the impacts]
The “standard loader” requires signatures by MFP vendors on the files as described above,
when the applications developed by users are uploaded to the MFP. Therefore, malicious
application files are not uploaded.
However, the loaders published by a vendor in 2002 had a function that allows application
upload without signature verification. It was considered not to be a problem if users do not
introduce the “loader without signature verification,” because the unauthorized applications
would not be uploaded as long as there was no “loader without signature verification”
introduced. However, attacks can succeed.
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With signature
verification
Upload the “loader without
signature verification”
Application
Protected
assets
Upload applications for
attacks
Users
(Attackers)
No signature
verification
Figure 7-7 Unauthorized application installation using SDK
1)
2)
3)
Upload the “loader without signature verification” using the “standard loader (loader
with signature verification).”
Upload applications for attacks using the function of the “loader without signature
verification.”
Attack the protected assets using the function of applications for attacks.
7.9.2 [Causes and discussion]
The cause of the successful attacks is a fact that the “loader without signature verification” was
officially published by the vendor. In other words, it was an application signed by the vendor.
The “loader without signature verification” can be uploaded without any problem to the MFP
that is not introduced with the “loader without signature verification,” because the application is
signed. Then, a maliciously created application was just uploaded according to the
specifications of the SDK that provides file operation command, etc., using the function of the
“loader without signature verification.”
The “loader without signature verification” was considered to be an application published for
the MFPs that do not handle protected assets. However, as a result of exploiting the application,
the protection function that “applications that are not signed are not uploaded” was disabled.
When the developers of the MFP vendors provide protection functions of the SDK, applications
that are provided for those environments, where protected assets are not handled, should be
managed in an integrated manner to prevent them from becoming a backdoor.
Supplement: Memory area protection breakthrough
In addition, the SDK protects the protected assets and the MFP with restriction to the memory
area that can be accessed by the applications uploaded by using the SDK, such as Sandbox of
Java. If one of the SDK libraries or functions has the parameters that cause buffer overflow,
there is a possibility that the memory area is broken through, and the MFP operations and the
protected assets can be attacked. In fact, the JRE has a report about the vulnerabilities caused
by defects of the functions of the SDK.
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Supplement: Protection of the applications developed by the users
It is necessary to consider the encryption that makes the applications created by users
confidential. It is difficult to assume that different keys are used for each different MFP for
encryption (decryption), considering the environment of the MFP. If the created applications are
considered to be assets, users may want to check the encryption mechanism provided by the
developers.
7.9.3 Measures
[Operation guide]
1)
Confirm with the developers that protection functions, such as encryption and
signatures provided by the SDK, meet the security policies of the users.
Operate the SDK by enabling the signature verification function. (The debug mode is
used only in an environment where the SDK is developed).
2)
[Development guide]
3)
The assessment criteria for the applications to be signed shall be standardized,
including applications for products whose security is not their concern.
Conduct a test of buffer overflow, etc., against all the libraries and functions provided
for the SDK.
4)
[Verification guide]
5)
6)
Verify that unauthorized application uploads cannot be made using the SDK.
Verify that vulnerabilities, such as buffer overflow, do not exist in the memory
protection functions of the SDK.
Ensure that the functions that are provided by the SDK do not lower the security level
of any of the original MFP functions.
7)
7.9.4 References
Date of publication
2003
Source
MEAP technical description
http://gijutsu.jbmia.or.jp/03kaisetu-canon.pdf
MEAP functional overview and the description of the protection mechanism
July 2002
Vulnerability in ChaiVM EZloader
http://en.securitylab.ru/notification/235126.php
Article about EZloader that does not perform signature verification
January 2012
CVE-2012-0507
http://cve.mitre.org/cgi-bin/cvename.cgi? name=CVE-2012-0507
Vulnerability report on BOF of JVM that can exceed Sandbox limitations
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7.9.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
When uploading the application, which can upload any other application described in this
section, onto the MFP, it is assumed that the use of the upload function of the applications using
the SDK generally is restricted to administrators. However, the cases when attackers break
through the administrator authentication, are assumed here. The following statement is also an
assumption:
- An attacker can use the development environment of the SDK.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
7.9 (Danger)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.10 Problems due to vulnerabilities of applications introduced to the user terminals
Applications28 that are provided by MFP vendors and introduced to the user terminals have
possible accessibility to the protected assets in the MFP. Even if the MFP is secure, it is
considered that the protected assets are leaked from the vulnerabilities of the software provided
for the user terminals. Developers shall provide to users the latest vulnerability information
about the applications that are introduced into the user terminals, and users need to regularly
check the vulnerability information such as CVN, etc., and conduct careful operations such as
temporarily halting the application introduced to the user terminals when the vulnerability is
published.
7.10.1 [Attack methods and the impacts]
For applications that are provided by MFP developers and introduced to the user terminals,
there have been lots of vulnerabilities reported in recent years as shown in the references. Most
of these vulnerabilities are not used to attack the main unit of the MFP directly, but allow the
attacks on the user terminals where the applications are to be installed. In simple logic,
protected assets on the user terminals (scan data or fax) before being sent to or after having
been received from the MFP can be exposed to the threats of tampering and leakage, and
protected assets in the MFP may be affected indirectly, if the administrator terminals are
hijacked. Many of them may be caused by buffer overflow, but some applications with
vulnerabilities to simpler attacks have been reported as well.
For example, by using a vulnerability of an application introduced into the user terminal, which
was reported in August 2011 as described in the references below, an attacker can attack the
user terminal with the application installed by taking the following steps:
Vulnerabilities used for the attacks are directory traversal with the SaveXML function of the
application. Install the vbs and mof files in the system directory under Windows and use the
mof file to execute the vbs file as follows: In order to install them, the following command
should be executed to open the unauthorized web pages and files in the user terminals to be
attacked.
- hoge.SaveXML(“../../../../../WINDOWS/system32/hoge.vbs”,”UTF-8”);
- hoge.SaveXML(“../../../../../WINDOWS/system32/wbem/mof/hoge.mof”,”UTF-8”);
Figure 7-8 Examples of files that are installed to attack user terminals
Execute any vbs file, which is set up by using the Windows Management Instrumentation
service, using the mof file. Then, protected assets on the user terminals can be emailed, or a
remote shell can be provided using the vbs file. Inspection codes have been published in the
Exploit Database29 of Metasploit that can be a reference for creating attack codes.
As a next step, attackers obtain information for accessing the main unit of the MFP by
analyzing the applications on the hijacked user terminals, or by collecting the data.30 Then, the
attackers access the MFP as administrators or users to obtain protected assets on the MFP
illegally, etc.
Software products provided by MFP vendors that come with the MFPs, such as printer drivers, etc., or
that can be downloaded from the Internet.
29http://dev.metasploit.com/redmine/projects/framework/repository/entry/modules/exploits/windows/browser
/hp_easy_printer_care_xmlsimpleaccessor.rb
30 For example, setting up packet analyzer or key loggers
28
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7.10.2 [Causes and discussion]
For applications that are assumed to be used on the MFP which handle protected assets and that
are intended to be introduced to the user terminals provided by the MFP vendors, it is required
to ensure the security level of the applications so that the security level of the application will
not be lowered by vulnerabilities. It is important to use the source code inspection tool31 or
review the source code manually, as is done for typical applications as measures, to prevent
vulnerabilities from being mounted. Unlike the examination of the applications built into the
MFP, the vulnerability testing of the printer driver is relatively easy for evaluators, because a
debugger, such as gdb or Ollydbg, suitable for the execution environment can be used.
Supplement: Vulnerabilities of OS and applications for the user terminals developed by third
parties
The above-mentioned attack methods can be used against the OS and applications developed by
third parties. There is a possibility that the MFP and the applications provided by MFP vendors
on the user terminals may be indirectly attacked by using the vulnerabilities of these
applications. For example, even if there is no vulnerability caused by the application that was
provided by a MFP vendor, and in cases when an attacker has acquired OS administrator
privileges on the user terminal using the vulnerability of the OS, the user passwords to access
the MFP may be leaked by performing debugging of the applications provided by the MFP
vendor or embedding by keylogger, etc., as described earlier. What users should not confuse is
that such vulnerabilities caused by the OS on the user terminals, other applications, and MFP
management software created by third parties shall be dealt with by users during operations. In
reality, more than 12 vulnerabilities32 of iPrint Client33 provided by Novell were published on
CVE since 2011. Some of the vulnerabilities are high-risk, which causes arbitrary code
executions.
Source code review “Secure Programming Course C/C++” by IPA
http://www.ipa.go.jp/security/awareness/vendor/programmingv2/contents/c103.html
32 CVE-2011-4186 CVE-2011-4185 CVE-2011-1708 CVE-2011-1707 CVE-2011-1706 CVE-2011-1705
CVE-2011-1704 CVE-2011-1703 CVE-2011-1702 CVE-2011-1701 CVE-2011-1700 CVE-2011-1699, etc.
33 http://www.novell.com/ja-jp/documentation/nw6p/pdfdoc/iprntenu/iprntenu.pdf
31
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7.10.3 Measures
[Operation guide]
1)
When considering the applications that are introduced to terminals as interfaces to the
protected assets, confirm that the applications provided by MFP vendors meet the policies
of users.
* It should be noted that other software on the user terminals, in addition to the applications
that are provided by MFP vendors, also need to be managed.
[Development guide]
2)
When providing applications for user terminals, they have to be manageable with a
security level equivalent to what is provided for the MFP.
[Verification guide]
3)
Regarding applications that are provided by MFP vendors, it needs to be examined for
their impact on the protected assets and examined as necessary.
7.10.4 References
Date of publication
October 2011
Source
Vulnerability of the MFP vendors’ applications to be introduced to user terminals
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-3163
Vulnerabilities of the HP software from which the workflow-metadata information can be obtained
March 2011
Vulnerability of the MFP vendors’ applications to be introduced to user terminals
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-0279
Vulnerability of the HP software that does not properly configure authentication settings of device
templates
Vulnerability of the MFP vendors’ applications to be introduced to user terminals
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2010-1558
Vulnerability of the HP software that protected assets can be obtained by exploiting the e-mail
function
Vulnerability of the MFP vendors’ applications to be introduced to user terminals
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-2404
Vulnerability of the HP software that protected assets can be obtained by exploiting the directory
traversal
Vulnerability of the MFP vendors’ applications to be introduced to user terminals
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2010-3920
Vulnerability of Seiko Epson printer driver by the temporary unauthorized privilege
May 2010
August 2011
December 2010
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7.10.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
The case of the user terminal being hijacked using the vulnerability described in the attack
methods is discussed in this section. The following are assumptions: In general, attacks on the
MFP are conducted by exploiting the hijacked user terminals. In such a case, confidentiality,
integrity and availability are all impacted overall. However, the procedure used until the user
terminal is hijacked is discussed here.
- Protected assets shall be on the user terminal.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
4.3 (Warning)
Possible attacks from networks
Moderate
No authentication operation required
Partial impact
No impact
No impact
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7.11 Problems due to vulnerabilities of many protocols
This section presents a comprehensive outline of a standardized protocol. MFP is one of the
devices among the embedded devices to operate and implement many protocols at the same
time. Because each protocol has its own respective vulnerability, the MFP that is implemented
with a number of protocols needs constant monitoring of vulnerability of the protocols
implemented by vendors. Maintenance systems are needed to perform such tasks as notification
to the users and application of patches, etc., when the vulnerability is determined to have an
impact on the implementation of the MFP.
7.11.1 Details
Figure 7-9 A list of communications protocols that are commonly used on the MFP
Figure 7-9 shows a list of communications protocols commonly used on the MFP.
“General-purpose networks” on the upper left are physical communications protocols, such as
Ethernet and wireless LAN. “Quarantine networks” are used for such purposes as to isolate
important hosts, such as MFPs, on the independent networks to automatically isolate the
terminals on the networks where important software has not been updated. “IP networks” are
procedures for transmitting application protocols, such as HTTP, by interconnecting multiple
networks to support the Internet. “Network storage” is a procedure that handles storage devices
such as a hard disk on the network. There is no such device for the current major MFPs.
“Network automatic configuration/control” is a procedure by which IP addresses can be
automatically distributed, host names can be converted to IP addresses, and service names can
be publicized to other machines. “Network authentication” is a procedure for the user terminals
or administrator terminals that are connected over the network to the MFP to verify users using
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user IDs between terminals and the MFP. “Network transferring/sharing” is a procedure for
performing the storage and exchange of document data via the MFP.
Dotted lines in the right half of Figure 7-9 shows the relationship between the transfer protocols
and the authentication protocols related to or corresponding to them. For example, a file sharing
protocol, called SMB, uses LDAP, Kerberos, and NTLM as authentication protocols. HTTP
uses HTTP Basic authentication and the HTTP Digest authentication. Because the IPP is
HTTP-based, it uses similar authentication protocols. The SIP is a type of protocol similar to
HTTP, and uses the same procedure as HTTP Digest authentication. There is a certification
procedure called SMTP AUTH and POP before SMTP to transfer emails. POP3, a procedure to
access the mail boxes, uses authentication protocol dedicated to POP3 (POP3 AUTH), and POP
before SMTP uses this. More sophisticated IMAP4 uses an authentication protocol dedicated to
the IMAP4 (IMAP4 AUTHENTICATION) to access the email boxes.
PDF password in the upper right corner of Figure 7-9 is a function to encrypt PDF files using
passwords. This is not a communications protocol, but is one of the protection functions of the
contents that are available for MFP users. S/MIME of the middle right in Figure 7-9 protects
email contents as well, and it also encrypts image data in the emails, and detects the tampering
of image data using electronic signatures.
Multiple protocols exist for each category above. Thereby, users can select the protocol suitable
for their environment.
For example, “network transferring/sharing” performs writing to and reading from the SMB
servers using SMB as a file transfer protocol. The FTP is a procedure for writing to and reading
from the FTP servers. Web services using the SOAP that are more enhanced on the HTTP
protocol are provided; in addition to writing and reading, publishing services are also available
for the HTTP.
Not all protocols are needed for the environment of specific users. However, vendors who ship
products globally have reasons to equip them with multiple protocols.
Products with these functions implemented had their respective vulnerabilities in the past. It is
believed that current MFPs do not contain these vulnerabilities, but that is not necessarily
always the case, because MFP functions are large even for software.
7.11.2 [Attack methods and the impacts]
There are multiple ways to attack multiple protocols implemented in the MFP, from simple
methods to advanced methods that require multiple steps, depending on the respective protocol.
The details about individual methods are omitted in this report, but various vulnerabilities have
been discovered in recent years for the main protocols of the MFP that are based on TCP/IP.
1)
Vulnerabilities of the Ethernet (IEEE 802.3)
Ethernet (IEEE 802.3) is a protocol to replace the Ethernet frame on the wire, and does not have
a function to protect the communications data. Ethernet is a simpler protocol than IP without
the routing function, but the network configurations have to be carefully performed, because
they are connected with the same Ethernet segment spreading to an unexpected scope with the
world wide Ethernet connection services.
A recent example of a vulnerability related to Ethernet is that some Ethernet device drivers did
not check the size of the Ethernet frame (CVE-2009-4537). Vulnerabilities are discovered as the
“Broadcom NetXtreme management firmware vulnerability to a buffer overflow (JVNVU
#512705)” in some cases, because remote management software has been added to the Ethernet
card (or module).
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Ethernet continues to change in such ways as achieving high-speed communications exceeding
10gbit/sec, and enhancing operation management functions to increase reliability while getting
more popular as an inexpensive standard communications interface.
2)
Vulnerabilities of wireless LAN
Wireless LAN has the ad hoc mode that connects terminals directly and the infrastructure mode
by which terminals communicate via access points, and the authentication in ad-hoc mode is
difficult. Originally, the access points that relay communications of other terminals should be
operated in well-controlled conditions, but a third party can easily navigate the fake access
points to connect wirelessly and invisibly, and easily connect to the fake access points to the
wireless LAN terminals.
Currently, it has not been used in security-conscious environments, but there is a problem that
the encrypting key can be decrypted in a matter of a few minutes in the WEP.
Regarding the security of wireless LAN, there are measures such as those used by the
protection system called WPA/WPA2 communications. The usage of secure wireless LAN is
introduced on the website, such as “Risks in the wireless LAN, Ministry of Internal Affairs and
Communications,”34etc.
3)
Vulnerabilities of Bluetooth
Bluetooth is a wireless communications standard that is used at a relatively short distance using
a frequency band of 2.4GHz. It uses the encryption by the stream cipher “E0” corresponding to
keys up to 128bit long, and the authentication challenge-response method by the pre-shared
PIN. General usages are the wireless connection between devices that are connected at all times,
such as PC keyboards and audio speakers, etc. They are also used for the data transmission and
reception between the tablet terminals and on the smart phones. Some MFPs have printing
functions, etc., that receive data from the terminals via Bluetooth. Bluetooth has a profile35
with a possibility of a backdoor such as SPP and DUN due to its specifications. It is said that
there is a high risk of vulnerability embedded, such as buffer overflow, etc., when the profile is
implemented.36
4)
Vulnerabilities of TCP/IP
The vulnerabilities of TCP/IP are summarized in the “Revised Research Report on Known
Vulnerabilities of TCP/IP, 5th Edition” by IPA. It contains vulnerabilities of ARP, IPv4, ICMP,
TCP, and UDP, and the software to verify these vulnerabilities, “TCP/IP Related Known
Vulnerability Assessment Tool V5.0,” is also distributed.
As TCP/IP operates in the OS kernel in general, the impact is great if vulnerabilities are
attacked, causing such events as the OS stopping.
5)
Vulnerabilities of IPv6
With the depletion of the 32-bit address of IPv4, IPv6 was standardized by the United States
Department of Defense in 1982 and has become available for most MFPs. The “Security impact
by IPv6 introduction and the measures”37 presented at the 13th Information Security
34
35
36
37
Risks in the wireless LAN
http://www.soumu.go.jp/main_sosiki/joho_tsusin/security/enduser/ippan12.htm
The unique communication procedure implemented for each type of devices
http://www.net-security.org/secworld.php?id=11663
http://www.imes.boj.or.jp/citecs/13symp/ref2.pdf
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Symposium, regarding possible vulnerabilities on the networks due to the protocol
specifications. 36 vulnerabilities related to IPv6 on the implementation leakage of OS’s and
applications are reported from January 2011 to July 2012 on the CVE public information. Those
service interruptions by DOS attacks due to OS implementation leakage and those bypassing
the access control lists have been confirmed.
6)
Vulnerabilities of DNS
DNS is a protocol used to convert host names, such as www.example.jp, into IP addresses. In
cases when only IP addresses are used without using the host names, DNS is not required.
However, DNS is often required in case of using the mail fax via the Internet.
The typical vulnerability of DNS is the “DNS cache poisoning” that injects fake IP addressed to
the hosts that are attempting name resolution in DNS by exploiting the lack of protection of
DNS messages. A method, DKA (Dan Kaminsky Attack), was discovered in 2008, and it was
pointed out that it has a great impact. Since then, a protection method called DNSSEC has
being introduced gradually to handle the vulnerabilities of DNS.
7)
Vulnerabilities of SNMP and SNMPv3
SNMP is a protocol for monitoring the operations mainly of the communications devices and
network devices. SNMP performs MIB (Management Information Base), a process that
responds with type values from the hierarchical name labels to access the information
indicating the operation state in the communications devices. On the SNMP protocol, message
data of both requests and responses are encoded in a binary format called ASN.1 (Abstract
Syntax Notation One), but a number of vulnerabilities are found in SNMP mainly of the
implementations of its interpretation of ASN.1.38
There was a vulnerability that the administrator passwords can be obtained when entering OID
such as “.iso.3.6.1.4.1.11.2.3.9.4.2.1.3.9.1.1.0” to the HP printers in 2002.39 The users need to
be limited in cases when the protected assets are in the information viewable on SNMP.
Therefore, the identification and authentication function has been added to SNMPv3, but the
vulnerabilities have also been discovered in the implementation of the authentication
procedures.40
Since then, SNMP provides easy selection of the transmission method to protect
communications by separating the specification that defines the SNMP message type from the
specification that defines the transmission of SNMP messages (RFC5590).
SNMP has a feature of query processing that traces hierarchical MIB information in a tree.
Therefore, some problems may occur in the operations of devices with many inquiries of MIB
information recursively, if there are wrong settings or no limit to the processing volume.
In addition, there are implementations that can define specific actions, such as “action” based
on the monitoring results via SNMP. Such implementations may allow executions of the
arbitrary commands, if actions are performed without examinations of the fake SNMP
responses.
38
39
40
http://www.ipa.go.jp/security/ciadr/20020213snmp.html
http://securitytracker.com/id/1004860
http://jvn.jp/cert/JVNVU878044/
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8)
Vulnerabilities of FTP
The FTP (File Transfer Protocol) has been very popular, because it has been the standard
protocol for file transfer over the Internet earlier than HTTP.
However, the FTP does not have procedures to protect communications over a long period of
time. Protective settings using IPsec were also difficult due to the complex structure of the
control TCP ports and the data transfer TCP ports that were separated. Improvements have been
made such that the FTP is used on the SSL/TLS, and that the control TCP ports and the data
transfer TCP ports are the same. However, there is no description in the products catalogs
whether they are introduced to the MFPs, so it could not be confirmed.
There is already a case that some FTP commands were exploited. The FTP port command is an
instruction that connects the TCP ports of any host’s port number to the other the FTP servers.
An example of exploiting the port command is the “FTP bounce attack.” The FTP site
command is a function to execute arbitrary commands on the connected FTP server, and it is
very dangerous to operate the FTP servers having this function. The FTP cwd command is a
command to move the current directory on the connected FTP servers. The cwd command is
used in combination with the FTP put command that writes files or the FTP get command that
reads files. However, it generally limits the accessible directories as some sub-directories on the
FTP servers to prevent the operations to the directories and files that require privilege.
As a usage of the FTP server, there is an anonymous FTP server that does not require
authentication. Anybody can use FTP servers by sending “ftp” or “anonymous” as user IDs
when logging in with the FTP protocol, and sending any password string. The implementations
of some FTP servers need attention to be paid to the FTP server operations, because normally
they may operate as anonymous FTP servers.
From the above circumstances, it is considered that considerable care for FTP use is required in
an environment that uses the MFP.
9)
Vulnerabilities of HTTP and HTTPS
The HTTP-based deletion services are installed into most MFPs because of their efficient
functions by utilizing the graphical user interfaces of the web browsers, and used quite
extensively. In addition, services that have specialized applications are HTTP-based, as well,
such as “IPP (Internet Printing Protocol)” that provides printing functions, “Web Services” that
provides automated processing between web servers, and “WebDAV” that provides access to
the shared files. HTTP communications are described in detail in Section 7.15 because there are
many vulnerability viewpoints.
The vulnerabilities of HTTPS have great impact, as well, because HTTPS (HTTP over
SSL/TLS) that protects HTTP communications path is also extremely popular. Vulnerabilities
of the renegotiation (it re-establishes a connection during SSL/TLS communication) function of
SSL/TLS have been reported in recent cases.
10)
Vulnerabilities of LDAP and Kerberos
LDAP and Kerberos are typical protocols to perform authentication and authorization
intensively on the networks. If LDAP and Kerberos are efficiently used, authentication can be
done without user registrations for every single MFP, which enables centralized management of
the password updates. However, the impact is great since authentication information and
authorization information are converged.
LDAP shall be used in conjunction with SSL/TLS, because it does not have a function to
protect communications. For Kerberos, version 4 and consecutive versions have the encryptions
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embedded into protocols. The LDAP servers may contain requests to execute LDAP injection
when searches are requested, such as for email addresses and IDs.
Recent vulnerabilities of LDAP include “Vulnerability of the denial of LDAP services (DoS) in
JVNDB-2009-001779 - Active Directory.”41 For Kerberos, “Vulnerability of the denial of
kadmind services (DoS) in JVNDB-2010-001344 - MIT Kerberos” should be referred.42
11)
Vulnerabilities of SMB
SMB (Server Message Block) is a protocol that provides file sharing services. Some
higher-level protocols called CIFS are also available, but they are referred to as SMB, including
CIFS in general.
SMB file sharing services are used to transfer files that were scanned from the MFP, or to
retrieve scanned images stored in the MFP from the user terminals, etc. Fax images that are
received via fax may be transferred directly from the MFP to the user terminals. It also may be
used for requesting the MFP to print.
The authentication procedure called NTLM has been used in SMB, but it has an improved
NTLMv2 because there is a problem of the easy cracking of passwords when passwords are
exchanged in NTLM. The NetBIOS protocol used in the SMB can be easily deceived by an
arbitrary fake response of resolving the SMB server names to the IP addresses using the
broadcast. SMB file sharing servers that ran on Windows earlier than Windows XP SP1 have
vulnerabilities that the file sharing function operates without passwords.43
The “vulnerability that arbitrary code is executed in the RPC code generator of
JVNDB-2011-005032-Samba” is about serious vulnerabilities and has been published in recent
years.44
12)
Vulnerabilities of SIP
SIP (Session Initiation Protocol) is a protocol to perform session control between two terminals.
SIP and RTP (Real-time Transport Protocol) are used for fax transmission on the MFP.
SIP has several specifications to protect communications, but the communications protection
function is not used in general, because SIP communications is supposed to be performed
between the communications carriers. On the other hand, the implementation of such products
using the SIP have vulnerabilities that can communicate with SIP servers and SIP terminals on
the Internet if IP address is specified, without protective functions for the communication. For
SIP, there is also a problem of unwanted incoming calls that are called “SPIM,” which are like
spam mails of e-mail.
The vulnerabilities of SIP are described in the “Revised Research Report on Known
Vulnerabilities of SIP, 3rd Edition” by IPA.45 “Evaluation tool on Known Vulnerabilities of SIP
V2.0” by IPA is distributed as well.46
Vulnerability of the denial of LDAP services (DoS) in JVNDB-2009-001779 - Active Directory”
-http://jvndb.jvn.jp/ja/contents/2009/JVNDB-2009-001779.html
42 Vulnerability of the denial of kadmind services (DoS) in JVNDB-2010-001344 - MIT Kerberos
-http://jvndb.jvn.jp/ja/contents/2010/JVNDB-2010-001344.html
43 http://itpro.nikkeibp.co.jp/members/NBY/techsquare/20021129/3/
44 http://jvndb.jvn.jp/ja/contents/2011/JVNDB-2011-005032.html
45 Revised Research Report on Known Vulnerabilities of SIP 3rd Edition
http://www.ipa.go.jp/security/vuln/vuln_SIP.html
46 Evaluation tool on Known Vulnerabilities of SIP V2.0
http://www.ipa.go.jp/security/vuln/vuln_SIP_Check.html
41
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13)
Vulnerabilities of SMTP, POP3, and IMAP4
SMTP is a protocol that transfers emails, and POP3 and IMAP4 are protocols that provide
access to email boxes. These have existed earlier than HTTP, and have been popular.
SMTP had various problems, because there were no authentication procedures or protection
procedures for communications in the specifications. Currently, there are still problems such as
receiving advertisements and a large volume of “spam mails” that computer viruses are
attached to.
A variety of vulnerabilities have been discovered in the implementations of these email
protocols. SMTP command has vulnerabilities on SMTP expn commands that deploy alias
addresses and member names on the mailing lists, as well as on SMTP vrfy commands that
verify the presence of email addresses without authentication. SMTP auth commands are
procedures for user authentication by the SMTP protocol, but it has a high possibility of the
password being cracked if the SMTP auth procedures are wiretapped to change hashed
password strings. In addition, it is necessary to protect the SMTP communications path with
SSL/TLS or IPsec to use SMTP securely, because there is no function to protect messages on
the SMTP communications path.
The recent SMTP information leakage vulnerabilities are described in “Information leakage
vulnerabilities in the SMTP component of Microsoft Windows.”47 Vulnerabilities of
authentication password exchange procedure of POP3 are described in “Vulnerabilities of
password leakage on APOP.”48 Vulnerabilities of response processing in both cases of IMAP4
and POP3 in recent years are reported in “Vulnerabilities of integer overflow in inetcomm.dll of
multiple Microsoft products.”49
S/MIME is a protection specification of messages and contents for the secure exchange of
emails and messages. Digital certificates need to be operated properly to ensure S/MIME
protection. It is also necessary to understand the cautions, such as the headers indicating
sources and destinations of the emails in the S/MIME not being protected. For more detailed
S/MIME usage, “Email security - encryption and electronic signature using S/MIME” should
be referred.50
JVNDB-2010-001391 - Information leakage vulnerabilities in the SMTP component of Microsoft
Windows - http://jvndb.jvn.jp/ja/contents/2010/JVNDB-2010-001391.html
48 JVNDB-2007-000295 - Vulnerabilities of password leakage on APOP
http://jvndb.jvn.jp/ja/contents/2007/JVNDB-2007-000295.html
49 JVNDB-2010-001471 - Vulnerabilities of integer overflow in inetcomm.dll of multiple
Microsoft products - http://jvndb.jvn.jp/ja/contents/2010/JVNDB-2010-001471.html
50 Refer to “Email security - encryption and electronic signature using S/MIME” by IPA
http://www.ipa.go.jp/security/fy12/contents/smime/email_sec.html
47
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7.11.3 [Causes and discussion]
1)
Many protocols
The MFP has various levels of protocols. As BMLinkS51 distributed by an industry association
of the MFP JBMIA, there are activities to develop a common driver compatible with multiple
models of MFPs of multi vendors. However, the existing protocols have dependencies on one
after another, such as user terminals’ conditions or constraints with other systems, and it is not
easy to put them into one protocol to aggregate.
It is effective for the fundamental countermeasures by developers that unnecessary services are
not implemented, and that the information, which can be accessed from the necessary services
to operate, should be narrowed down to its minimum. As users, it is effective not to start up the
non-used services for operation.
In real attacks, attackers conduct port scans for the MFP to verify that these services are
running. The MFP may be excluded from the target of attacks during the early stages of attacks
by suppressing the port scan and concealing the services. There are two major ways to control
the port scan. One is to modify the kernel so as not to respond to scanning to some extent, and
the other is to modify the kernel for all 65,535 ports to respond to scanning. Both methods are
effective in terms of available ports (services) not being identified. However, port scans need to
be handled on the assurance of no impact on the services and functions that are implemented on
the MFP and on the linkage function with external devices.
2)
Measures including ex-post facto measures against the vulnerabilities that are still
being discovered
As mentioned above, many services are running on the MFP along with rich functions of the
main unit of the MFP. Therefore, the vulnerabilities of the MFP cannot be totally eliminated.
Vulnerabilities of the software, as listed in “7.11.2 [Attack methods and the impacts],” are
reported on some implementation of any protocols. In fact, vulnerabilities of SMB implemented
onto many MFPs were reported and published in April 2012.
Assuming that the vulnerabilities of the MFP cannot be totally eliminated, MFP users and
developers of the MFP vendors need to prepare ex-post facto measures respectively. Users can
take ex-post facto measures for the vulnerabilities, including gathering vulnerability
information about the products being used and measures from the vendors, establishing the
systems to support software updates and the usage procedure changes, and discussing response
procedures for damages with personnel in charge, etc.
Examples of ex-post facto measures for the vulnerabilities that the providers of the products can
take would be identifying the vulnerabilities and the report procedures, discussing the methods
of reduction of damages and threats, discussing how to reflect that to products, and prioritizing
measures.
51
BMLinkS-JBMIA: Japan Business Machine and Information System Industries Association,
The BMLinkS Project Committee http://bmlinks-committee.jbmia.or.jp/
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3)
Measures for the vulnerabilities of multiple protocol implementation
In circumstances in which there is no choice but to implement many protocols at the same time,
designs to minimize the vulnerabilities of the MFPs and measures for developers can be
referred to the widely disseminated “Security Engineering,”52 “Secure Programming
Course,”53 and “Approaches for embedded system information security,”54 etc., by IPA.
It is difficult that there are too many matters to discuss and too many testing items in the
existing methods for these vulnerability measures to be implemented. Therefore, more
examinations of some automated test tools and inspection methods may be necessary.
Test tools include tools to discover the vulnerabilities by examining source code,55 fuzzing
tools to comprehensively check by rewriting HTTP communications of the products, and the
tools to discover the vulnerabilities by testing from outside in a black box manner, etc. IPA
published materials that cover description of fuzzing and specific usage of the fuzzing tools.56
Codenomicon, AppScan and Nessus, etc., are well-known products to examine vulnerabilities
in a black box manner. For the evaluation procedures, including tests for these vulnerabilities,
the product certification system, including vulnerability tests, which were performed at
Windows Logo of Microsoft, can be referred.57
However, these tools can only apply to the standardized protocols for HTTP communications,
and it should be noted that the manufacturing vulnerabilities that can be detected by manual
checking cannot be detected on HTTP communications.
52
53
54
55
56
57
“Security Engineering” by IPA – http://www.ipa.go.jp/security/awareness/vendor/software.html
“Secure Programming Course” by IPA
http://www.ipa.go.jp/security/awareness/vendor/programming/
“Approaches for embedded system information security”
http://www.ipa.go.jp/security/fy20/reports/emb_app/
“Secure Programming Course C/C++Language” source code review by IPA
http://www.ipa.go.jp/security/awareness/vendor/programmingv2/contents/c103.html
http://www.ipa.go.jp/security/vuln/fuzzing.html
Windows Logo - http://www.microsoft.com/japan/whdc/winlogo/hwrequirements.mspx
Product certification examination system that is provided for Windows device driver
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7.11.4 Measures
[Operation guide]
1)
Disable all the functions that are not used while minimizing the functions used on the
MFP.
Subscribe to the vulnerability measures information of the vendors or prepare to obtain
it any time.
Regularly understand trends and security breaches obtained by the audit records, and
take measures.
Have plans to take measures in cases that the vulnerabilities of the MFPs are found.
Have plans to take measures in cases of damage caused by the vulnerabilities.
2)
3)
4)
5)
[Development guide]
6)
Manage the services that are implemented, but do not implement services no longer
being used.
Clearly define and specify the communications that allow access to the protected assets.
In some cases, implement the measures against attacks at the kernel level.
Measures against the vulnerabilities of the products should be addressed through
product planning and development processes.
Consider tools likely to easily reflect the security policy for the MFP that can be
applied in a usage environment of the MFP.
Consider using static analysis tools for source code, fuzzing tools and intrusion testing
tools as vulnerability testing tools.
Have handling procedure plans ready to deal with situations in cases that
vulnerabilities are found.
7)
8)
9)
10)
11)
[Verification guide]
12)
13)
When examining a communications protocol that can access the protected assets, all
parameters should be targets for inspection regardless of input availability for users.
Perform comprehensive inspections by understanding what can be examined and how
much it can be examined by use of vulnerability assessment tools, and by using the
source code review or manually to check the parts that cannot be examined.
7.11.5 References
Date of publication
February 2002
Source
IPA: Widespread vulnerabilities of SNMP
http://www.ipa.go.jp/security/ciadr/20020213snmp.html
Vulnerability information related to SNMPv1
2008
Information security measures for SE - vulnerability of HTTP
http://www.chuu-information.com/security/fragile_6.html
Points of vulnerabilities in the HTTP protocol are summarized
June 2008
JVNVU#878044
Vulnerabilities of authentication bypass due to improper HMAC processing under SNMPv3
implementation
http://jvn.jp/cert/JVNVU878044/
Vulnerabilities that authentication is bypassed in SNMPv3 due to specific messages
An Illustrated Guide to the Kaminsky DNS Vulnerability
http://unixwiz.net/techtips/iguide-kaminsky-dns-vuln.html
Overview and handling of CACHE Poisoning by DKA
July 2008
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November 2010
IPA: Research Report on Known Vulnerabilities of TCP/IP Revised 5th Edition http://www.ipa.go.jp/security/vuln/vuln_TCPIP.html
Vulnerability materials of detailed descriptions of TCP, ICMP, IPv4, and ARPs protocol
November 2010
IPA: Evaluation tool on Known Vulnerabilities of TCP/IP V5.0
http://www.ipa.go.jp/security/vuln/vuln_TCPIP_Check.html
Compatible with TCP, ICMP, IPv4, ARP and some IPv6
November 2009
JVNVU#120541
Vulnerabilities of SSL and TLS protocols
http://jvn.jp/cert/JVNVU120541/
Vulnerabilities of functions used to re-connect during the SSL/TLS communications
CVE-2009-4537: r8169: straighten out overlength frame detection
http://cve.mitre.org/cgi-bin/cvename.cgi? name=CVE-2009-4537
Failure of the frame length test that was included in the driver of Realtek Ethernet chip
December 2009
July 2011
CVE-2011-1265
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-1265
Vulnerability that the Microsoft products execute codes due to unauthorized Bluetooth packets
April 2012
CVE-2012-0475
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2012-0475
Vulnerability that the access control list of IPv6 literals of Mozilla products is bypassed
May 2012
CVE-2011-2699
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2011-2699
Vulnerability of the impact of a DOS attack in an IPv6 implementation of Linux OS
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7.11.6 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
Multiple protocols are introduced in this section, but it is assumed that the MFP services are
stopped due to DOS attacks on the HTTP server inside the MFP using attack tools.
- It has to be the model that does not take the above measures in the operation guide.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
Requirement
Confidentiality
Integrity
Availability
5.8 (Warning)
Possible attacks from neighboring
networks
Low
No authentication operation required
No impact
No impact
Overall impact
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7.12 Concerning vulnerabilities of proprietary MFP protocols
This section explains proprietary protocols that are not included in the standardized protocols
described in Section 7.11. Proprietary protocols refer to communications protocols developed
or modified by vendors independently to provide communications services with other devices
than the MFP. Vulnerabilities are not found by use of the inspection tools described in Section
7.11, unlike the standardized protocols. On the other hand, starting from the design and
development stage, there may be bugs in the implementation leading to vulnerabilities, such as
buffer overflow, etc., at unexpected locations. In this section, examples of the source code in the
communications control are presented to show locations where leakage and bugs are likely to
occur. These source code examples are for reference only, and are not the services implemented
on the MFP.
7.12.1 [Attack methods and the impacts]
It is confirmed that some MFP vendors implement services that are assigned to ports other than
general ports. Some only offer communications services with the standardized communications
protocols via proprietary port numbers as listed in Section 7.11. However, some vendors
implement their own proprietary services to provide additional services and cooperation devices
provided by the vendors. In cases of the proprietary services by vendors, the specifications,
such as the standardized communications protocols of well-known ports in RFC, etc., will not
be published. In addition, unlike the services known to the general public, vulnerabilities are
not identified. To put it better, they are unlikely to become targets of the attacks, and their
vulnerabilities and attack methods are rarely published. On the other hand, it is possible that the
vulnerabilities covered in well-known services may still exist.
Examples of the vulnerabilities of the protocols whose implementations have not been
confirmed on the MFP are presented here, to describe the vulnerabilities that may occur at the
time of implementation or in the specifications of proprietary protocols.
Vulnerabilities were published on July 7th, 2012, in the CVE of the references. Figure 7-10 is
the source code of communications control for the well-known message exchange tool. This
vulnerability is that the arbitrary code can be executed with buffer overflow triggered in the
stack area by exploiting the regular inline images attached to the messages, in other words, the
area of the size-defined icon (similar to pictogram used in the cell-phones).
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void mxit_show_message( struct RXMsgData* mx )
{
char*
pos;
int
start;
unsigned int
end;
int
emo_ofs;
char
ii[128];
char
tag[64];
int*
img_id;
if ( mx->got_img ) {
while ( ( pos = strstr( mx->msg->str, MXIT_II_TAG ) ) ! = NULL ) {
start = pos - mx->msg->str;
emo_ofs = start + strlen( MXIT_II_TAG );
end = emo_ofs + 1;
while ( ( end < mx->msg->len ) && ( mx->msg->str[end] ! = '>' ) )
end++;
if ( end == mx->msg->len )
break;
/* end of emoticon tag not found */
memset( ii, 0x00, sizeof( ii ) );
memcpy( ii, &mx->msg->str[emo_ofs], end - emo_ofs );
/* remove inline image tag */
g_string_erase( mx->msg, start, ( end - start ) + 1 );
/* find the image entry */
img_id = (int*) g_hash_table_lookup( mx->session->iimages, ii );
if ( ! img_id ) {
/* inline image not found, so we will just skip it */
purple_debug_error( MXIT_PLUGIN_ID, "inline image NOT found (%s)\n", ii );
}
else {
/* insert img tag */
g_snprintf( tag, sizeof( tag ), "<img id=\"%i\">", *img_id );
g_string_insert( mx->msg, start, tag );
}
}
}
Figure 7-10 Example of source code that performs vulnerable protocol processing
Lines in red are where problems reside. Large character strings of str [mem_ofs] can be input to
the variable ii, which is ensured by a fixed 128 Bytes, so that it allows the overflow of the stack
area to rewrite the return addresses. As a result, it makes it possible to run a shell with
administrative privilege and arbitrary code. It is said that the seizure of the shell is difficult for
some OS’s that are installed on the MFP. There are some examples, however, that the OS
vulnerabilities are actually applied to the MFP with a general-purpose OS installed, as
described in Section 7.8.
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Buffer overflow mechanisms and the attack code to run the shell using an implementation that
can write any value to the stack area, as described above, are published on the IPA website.58
7.12.2 [Causes and discussion]
The cause of this vulnerability is that the function that triggers a buffer overflow has left
unnoticed during development, and has been implemented. Inspections by the fuzzing tool after
implementation may be effective if it is a general protocol port.59 However, in the case of
proprietary protocols, it is necessary to consider the design and inspection methods based on the
property of the protocols being used.
Vulnerabilities at the implementation level, as described in Section 7.12.1, occur mainly for the
reasons that coding rules are not coordinated in the development environment, or that a
checking mechanism is not established as to whether the development is following the rules, etc.
Deficiencies may be found at the time of the design or inspection, assuming the possibility that
unauthorized values are input in the texts input by users or in the pull-down items to select. In
this case, they may be missed from the targets of inspection, because they are processed inside
the programs to handle the areas where the fixed images or the icons, etc., prepared by the
vendors should be entered.
When it is programed with the fixed coding rules, design and inspection of the variable area and
its manipulations should be carefully paid attention to. It is confirmed that the program listed as
an example has been improved as follows when the current source code is downloaded:
:
int
char*
char
int*
:
emo_ofs;
ii;
tag[64];
img_id;
if ( end == mx->msg->len )
break;
/* end of emoticon tag not found */
ii = g_strndup(&mx->msg->str[emo_ofs], end - emo_ofs);
/* remove inline image tag */
g_string_erase( mx->msg, start, ( end - start ) + 1 );
:
g_snprintf( tag, sizeof( tag ), "<img id=\"%i\">", *img_id );
g_string_insert( mx->msg, start, tag );
}
g_free(ii);
:
Figure 7-11 Improved source code that performs protocol processing
Using static analysis tools for source code is effective during development for the
manipulations of variable area that is easily overlooked visually otherwise. In addition,
measures of port scanning at the kernel level as described in Section 7.11 may be effective as a
measure to interrupt with the presence detection of proprietary protocols that are breakthroughs
of attacks.
58
59
http://www.ipa.go.jp/security/awareness/vendor/programmingv1/b06_01.html
The vulnerability created by session maintenance management, etc., cannot be detected in many cases, if
inspections combined with a manual method are not conducted.
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On the other hand, vulnerabilities cannot be found in many cases using the vulnerability
inspection tools as described above, when evaluators conduct black-box testing of services
using proprietary protocols that have been implemented on the MFP. Proprietary protocols are
not examined using the inspection tools based on the databases of known vulnerabilities, such
as Nessus, and automatic inspection tools for proprietary protocols do not exist. Some may be
examined with fuzzing tools, if proprietary protocols have been extended from some
standardized protocols, but the extended parts may not be examined in many cases. Therefore,
when proprietary protocols are examined at the implementation level, it is necessary for the
persons performing manual intrusion testing to search the parameter parts and to verify
comprehensively that no overflow occurs by entering unauthorized values for the parameter.
In cases that the proprietary protocols are examined, it is realistic for the evaluators to ask
developers to disclose the source code to review and confirm by using static analysis tools to
perform analysis. In cases when the source code cannot be obtained, it is very difficult to debug,
so attack code shall be created while checking the responses by entering unauthorized values
into the parameter parts, after hearing the communications protocol specifications. Many
examples of attack code that insert unauthorized code into the parameter parts are published in
the Exploit Database of Metasploit.
7.12.3 Measures
[Operation guide]
1)
2)
Disable all the functions that are not used while minimizing the functions used on the
MFP.
Subscribe to the vulnerability measures information of the vendors or prepare to obtain
it any time.
[Development guide]
3)
4)
5)
6)
7)
Manage the services that are implemented, but do not implement services no longer
being used.
In cases when there is no impact on the other functions, consider the implementation of
measures for the port scan.
Ensure that the source code is compliant with coding rules for all parameters of the
protocol implemented.
Consider using static analysis tools of source code as vulnerability testing tools during
development.
Have handling procedure plans ready to deal with situations in cases that
vulnerabilities are found.
[Verification guide]
8)
9)
10)
When examining a communications protocol that can access the protected assets, all
parameters should be targets for inspection regardless of input availability for users.
Research if the vulnerability at the implementation level cannot indirectly access the
protected assets.
Manually examine after checking the specifications of the proprietary protocol (using
fuzzing tools, etc., if available). Examine by using static analysis tools and the source
code review if the source code review is possible.
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7.12.4 References
Date of publication
July 2012
September 2012
(Frequently updated)
March 2012
Source
CVE-2012-3374
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2012-3374
Vulnerability information of implementation leakage of message exchange software
called Pidgin
Exploit Database of Metasploit
http://www.metasploit.com/modules/
Code collection that will be helpful in creating such code associated with the overflow of
proprietary protocols, etc.
Guide for fuzzing usage
http://www.ipa.go.jp/security/vuln/documents/fuzzing-guide.pdf
Detailed description of fuzzing
7.12.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
The vulnerability described in this section is a bug that contains parameters, which can cause a
buffer overflow in the proprietary protocol that the MFP has implemented. It is intended to
obtain the authority to perform an OS command on the MFP by providing a backdoor by
exploiting the parameters to execute arbitrary code. The scope of the impact is assumed to be
that the protected assets can be manipulated completely from the OS command.
- It has to be the model that does not take the above measures in the development guide and
verification guide.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
7.9 (Danger)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.13 Problems of intrusion via driver protocol
As shown in Table 7-2, many driver protocols are supported in the standards of the recent MFP
to select and use freely in accordance with the usage.
Table 7-2 Major driver protocols used on the MFP
Driver protocols
LPR
raw9100
IPP
SMB
TWAIN
FTP
WebDAV
SMTP
POP3
IMAP4
WSD (Web Service
Discovery)
BMLinkS
Usage
Printing
Printing
Printing
Printing and scanning
Scanning
Scanning
Scanning
Faxing
Faxing
Faxing
Printing, scanning, and
faxing
Printing, scanning, and
faxing
Authentication
procedure










Encryption
procedure










There are a number of vulnerabilities reported from clients in the implementation of the driver
protocols to operate the MFP. By exploiting these vulnerabilities, various attacks are possible,
such as unauthorized operations of the MFP (display screen spoofing and requests for
unintended print processing, etc.), information leakage and data damage by unauthorized access
to the stored protected assets, and instability on the MFP operations from system file damage,
etc.
It is important for both developers and users to be aware of the vulnerabilities of the driver
protocols and their impacts and to take necessary measures, because of the possible
implementation (version) with remaining vulnerabilities to ensure compatibility with the
devices connected to the MFP.
LPR as an example of vulnerability of driver protocols is discussed here.
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7.13.1 [Attack methods and the impacts]
Figure 7-12 Example of intrusion via driver protocol LPR
First of all, an attacker establishes a TCP connection to TCP 515 port of the LPR server
executed on the MFP. The attacker then sends an LPR command unconditionally to the LPR
server on the MFP, because there is no procedure for user authentication of the LPR protocol.
Against the LPR server on the MFP, the attacker causes a buffer overflow by giving an
unexpectedly long character string as a file name of the control file for printing. Followed by
this very long character string, the attacker sends arbitrary executable code to the LPR server
and sends the line feed code (LF: 0x0a) as an end-of-command to the LPR, and then, buffer
overflow occurs in the LPR server so that the executable code sent by the attacker takes control.
Figure 7-13 below shows an example of a sequence of intrusion by the LPR command.
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Figure 7-13 Example of a sequence of intrusion by driver protocol LPR command
As a result, arbitrary code is executed by the attacker in the execution environment where the
LPR server is executed on the MFP. Once the attacker executes arbitrary code on the MFP, it is
possible to execute another program on the MFP by introducing it, copy documents and job
data handled by the MFP to the attacker’s host, and attack another host from the MFP. Even if
the attacker is unable to execute arbitrary code on the MFP, and if buffer overflow occurs on the
LPR server on the MFP, that may stop the operations of the LPR server, or the LPR server or
the MFP may re-start. As a result, the LPR server of the MFP or the MFP becomes temporarily
unavailable.
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7.13.2 [Causes and discussion]
In the LPR protocol, some commands are standardized to control the printing. However, there
is no argument that indicates the length of the command string, and the character strings, which
become arguments, are only separated by LF (Line Feed) code in the LPR protocol command.
Besides, there is a command to specify the names of the job data files and job control files that
are transferred, and arbitrary character string can be specified as a file name, but there is no
argument to specify the character string length of the file name. In addition, both job control
files and job data files have arguments that represent the length of the files in bytes, but they are
specified by a number in text format with no limitation to the maximum length or number of
digits indicating the length of the files.
In RFC 1179 where the LPR protocol specifications are standardized, the string length of the
job data file names and the job control file names are about six characters. However, an
unlimited number of characters can be sent, because there is no limit on the length of the string
in the LPR protocol.
In addition, a heap memory overrun may occur when the unexpected scope is being specified in
handling the numbers presented in the texts.
The “relaxed” protocol specifications by textual representation are common in procedures, such
as HTTP, SMTP, and SIP. On the contrary, the receivers need detailed inspection due to the high
flexibility instead of strict formats. Such inspection processing of the data received from the
outside is called “verification of input values,” “sanitization of input data,” or “sanitization.”
Refer to the “Secure Programming Course, C/C++ Language, Conspicuous vulnerability
measures” by IPA for the vulnerabilities and measures for development, presented with image
on the web.
The assumption for making this attack more successful is that the LPR server execution
environment on the MFP should be a well-known OS, such as Linux, Windows, or VxWorks,
and that the CPU or machine language used should also be well-known to operate the
executable code injected as attackers intended. An environment to execute the machine
language located on the stack memory or heap memory is also required.
Many protocols are supported for the MFP driver protocols, and there is a possibility that
vulnerability, such as LPR, remains in other driver protocols as well. Developers of the MFPs
need to confirm vulnerabilities for each driver protocol used on the MFP as shown in Table 7-2.
In particular, lots of vulnerabilities are reported in the implementation of the driver protocols
(LPR, IPP, or raw9100, etc.) operated on the MFP, as shown in the references. It is desirable to
check the latest vulnerability information in the implementation of driver protocols used in the
MFPs that are being developed, and it is also desirable either to publish patches and notify users
on the product information sites, or to replace the firmware with a patch applied against the
vulnerability on the basis of the maintenance contract, because the driver protocols may be used
unintentionally with vulnerabilities remaining in the implementations for the purpose of
assuring compatibility, etc., with the devices connected to the MFP. On the other hand, when
MFP users are intended to ensure security, it is effective to close the unnecessary ports with the
MFP settings by limiting the driver printer ports that are needed for use in the operational
environment.
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7.13.3 Measures
[Operation guide]
1)
2)
Specify servers used on the MFP, such as LPR, raw9100, IPP, SMB, SOAP, or
WebDAV, to stop the listen ports for the services that are not used on the MFP. On that
basis, check the vulnerability information of the MFP vendors to consider
implementation of necessary measures, if necessary.
Use only specific print spool servers or gateway servers for scanning and faxing, as the
host that can input job data for the MFP.
[Development guide]
3)
Always check the latest vulnerability information for driver protocols implemented on
the MFP, and notify users. In the case of vulnerabilities having an impact on the
proprietary MFP, provide patches or firmware that correspond to the vulnerabilities, in
addition to giving notice about them.
[Verification guide]
4)
5)
Check all driver protocols that are introduced on the MFP as to whether the known
vulnerabilities of each protocol apply.
Check all driver protocols that are introduced on the MFP as to whether they are
implemented correctly according to specifications, when vulnerabilities are handled by
implementation.
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7.13.4 References
Date of publication
August 1990
July 1998
October 2000
November 2001
October 2006
October 2007
December 2007
April 2010
Source
RFC 1179 Line Printer Daemon Protocol
http://tools.ietf.org/html/rfc1179
Protocol specifications of LPR by IETF
What is LPR?
http://support.apple.com/kb/TA21876? viewlocale=ja JP&locale=ja JP
Support information from Apple Computer. The difference between the LPR and the PAP (Printer
Access Protocol), a print job transmission procedure used on AppleTalk by Apple, is described.
LPD Vulnerability Issues
http://lpd.brooksnet.com/lpd-security.html
Points and example measures on the print server are as follows:
(1) Arbitrary file can be created on the print server via LPR.
(2) Arbitrary file can be deleted on the print server via LPR.
(3) Arbitrary command can be executed on the print server via LPR.
CERT® Advisory CA-2001-30 Multiple Vulnerabilities in lpd
http://www.cert.org/advisories/CA-2001-30.html
Multiple vulnerabilities on the print server of the LPR (lpd)
(1) Arbitrary code is executed by buffer overflow
(2) Arbitrary options can be specified to the sendmail on the print server.
The difference between LPR protocol and the standard TCP/IP port monitor
http://www.atmarkit.co.jp/fwin2k/win2ktips/809stdprnprt/stdprnprt.html
The difference between raw9100 and the LPR that are used on Microsoft Corporation’s TCP/IP port
monitor.
US-Cert: Cisco IOS LPD buffer overflow vulnerability: VU#230505
https://www.kb.cert.org/vuls/id/230505
Buffer overflow occurs after the call of sprintf() on the LPD of Cisco IOS, if a host name that exceeds
99 characters is entered.
US-Cert: CUPS buffer overflow vulnerability: VU#446897
http://www.kb.cert.org/vuls/id/446897
It has been reported that arbitrary code may be executed due to the vulnerability of buffer overflow in
the “Common UNIX Printing System (CUPS),” the printing system of the UNIX OS.
Mocha W32 LPD Remote Buffer Overflow Vulnerability
http://www.securityfocus.com/bid/39498/info
Vulnerability that arbitrary code is executed due to buffer overflow of the control file name character
string by the control file incoming command of the LPR on the Mocha’s LPR print server software for
Windows. There is an exploit code for the procedure by Python script.
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7.13.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
As an example of buffer overflow vulnerability of LPR protocol (arbitrary code is executed on
the LPR server.), a backdoor is established by executing arbitrary code by exploiting the
vulnerability, to obtain the authority to execute the OS command on the MFP. The scope of
impact is assumed to be a case that the protected assets can be manipulated completely from the
OS command.
- It has to be an environment that does not take the above measures.
- The LPR communications from the Internet are blocked by a firewall, etc.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
Requirement
Confidentiality
Integrity
Availability
7.9 (Danger)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.14 Problems due to vulnerabilities of page description language
Page description language is a language used to give instructions for output images, etc., when
documents and images created on the client PC are printed by the MFP, etc., and to set up
environments, and so on, and it includes PJL (Print Job Language), PCL (Printer Control
Language), and PostScript. In general, it is possible to input a print job or deletion queue, etc.,
using page description language on the MFP. On the other hand, there may be exposure or data
damage by unauthorized access to the data (protected assets) registered with printing jobs by
attackers, or obtaining passwords by unauthorized access to the file system, etc. As an example
of the page description language, PJL is discussed here.
7.14.1 [Attack methods and the impacts]
PJL specifications make it possible to perform MFP environment settings, job management
preferences, or file system operations, etc., using the PJL command. The following show PJL
commands related to file system operations:
Table 7-3 PJL commands related to file system operations
PJL commands
FSAPPEND
FSDIRLIST
FSDELETE
FSDOWNLOAD
FSINIT
FSMKDIR
FSQUERY
FSUPLOAD
Details
A command to add data to files or to create a new file
A command to display files and directories
A command to delete files or empty directories
A command to download files
A command to initialize file systems
A command to create directories
A command to inquire about the entry
A command to upload files
By exploiting PJL commands as shown above, there are possibilities of information leakage,
data damage, or unauthorized access to the file system, etc., by obtaining the data (protected
assets) registered by someone else.
The following example shows unauthorized access to the file system on the actual MFP by the
directory traversal method, using the command (FSDIRLIST command) related to file system
operations described above:
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%[email protected] INFO FILESYS
VOLUME
TOTAL SIZE
0:
2929683456
FREE SPACE
2922577920
LOCATION LABEL
HDD
STATUS
READ-WRITE
%[email protected] FSDIRLIST NAME="0: ..\..\..\..\\" ENTRY=1 COUNT=128
ENTRY=1
pjl TYPE=DIR
plwform TYPE=DIR
artform TYPE=DIR
seal TYPE=DIR
smb TYPE=DIR
jtpool TYPE=DIR
del TYPE=DIR
%[email protected] FSDIRLIST NAME="0: ..\..\..\..\smb\\" ENTRY=1 COUNT=128
ENTRY=1
passwd.txt TYPE=FILE SIZE=243
share.txt TYPE=FILE SIZE=67
Figure 7-14 Attack using a PJL command (Directory traversal)
The above example shows attackers can obtain file system information by accessing raw9100
(9100/tcp) of the MFP, and access the directory configuration information or protected assets
(passwd.txt, here), using the directory traversal methods based on the information obtained. It is
possible to obtain, or tamper with, files using the PJL commands, if the protected assets are
within the reach of access. It was actually confirmed that passwd.txt was obtained and tampered
within this attack.
In the case that the page description language is exploited, it is sometimes possible to tamper
with the MFP display (using RDYMSG commands) or with settings information, in addition to
unauthorized access to the protected assets as described above. In addition, there is an attack
reported that arbitrary code may be executed by triggering a buffer overflow using the
INQUIRE command. Exposures or damage of the protected assets stored in the MFP, or
destruction of the MFP itself, may be possible in some cases, using these attack methods.
Developers should develop while keeping the vulnerabilities of the page description language
in mind, because PostScript, as shown in the references besides PJL, also has been reported to
have vulnerabilities.
7.14.2 [Causes and discussion]
The causes for making unauthorized access to the file system on the MFP possible are the lack
of support of developers for a directory traversal and the implementation of unnecessary PJL
commands.
For the measures against the directory traversal, it is important to implement with limitations on
access to files or directories that can be accessed using the PJL commands, assuming that
attackers exist on the network that is accessible to the MFP. Additionally, it is effective to limit
the PJL commands available on the MFP (or keep it unavailable) as a measure against
vulnerabilities, such as the leakage of protected assets and settings information, as well as
buffer overflow, etc.
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7.14.3 Measures
[Operation guide]
1)
2)
Limit the host that can input job data for the MFP, such as to specific print spool
servers or gateway servers for scanning and faxing, etc.
Confirm the lists of PJL commands that are available on the MFP with the developers,
and contact them if there are any unnecessary commands.
[Development guide]
3)
4)
5)
Limit access to files and directories accessible by PJL commands.
Limit PJL commands available on MFPs. (Limit the necessary functions for users)
Execute all available PJL commands, including information confirmation commands,
to ensure that the behavior of the MFP or information that can be obtained do not have
any problems.
[Verification guide]
6)
Create valid attack code for inspection of the MFP to be examined, to confirm that
there are no problems in the behavior or information that can be obtained, using the
published references of attack codes by PJL commands, such as directory traversal and
buffer overflow, etc.
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7.14.4 References
Date of publication
Source
June 2003
HP PCL/PJL Reference
(Printer Job Language Technical Reference Manual)
http://h20000.www2.hp.com/bc/docs/support/SupportManual/bpl13208/bpl13208.pdf
PCL/PJL specifications of HP
March 2010
CVE-2010-0619
http://cve.mitre.org/cgi-bin/cvename.cgi? name=CVE-2010-0619
Report of buffer overflow using PJL INQUIRE command
November 2010
HP LaserJet Directory Traversal on the PJL Interface
http://www.exploit-db.com/exploits/15631/
Report on directory traversal using PJL commands
January 2012
Hacking MFPs PostScript(um–you’ve been hacked)
http://andreicostin.com/papers/Conf%20-%2028C3%20-%20Hacking%20MFPs%20(part2)%20-%20
PostScript_um%20you_ve%20been%20hacked%20-%20SRLabs%20-%20v2.pdf
Report on the vulnerabilities of PostScript
February 2012
MULTIFUNCTION PRINTER VULNERABILITIES
http://msisac.cisecurity.org/resources/reports/documents/A-0012-NCCIC-130020120223MFPVulnera
bility.pdf
Vulnerabilities of MFPs are referred to extensively
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7.14.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
An attack method to obtain protected assets using PJL commands by accessing the protected
assets using directory traversal is discussed here. The following is an assumption:
- The MFP cannot be accessed directly from the networks outside of the companies
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
Requirement
Confidentiality
Integrity
Availability
5.8 (Warning)
Possible attacks from neighboring
networks
Low
No authentication operation required
Partial impact
Partial impact
Partial impact
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7.15 Problems due to vulnerabilities of the web management console
It is common for MFPs in recent years that all types of security settings, etc., including MFP
network and printer settings, status management of the print function, jobs and devices, as well
as the backup function, have been performed using the web management console. Typically, the
web management console provides functions corresponding to the user category, such as MFP
administrators, general users, or maintenance personnel, etc. These functions are used by user
category by performing user identity authentication and access control. Therefore, the web
management console provided by the MFP is also required to take measures against common
vulnerabilities as a general web application that includes web servers inside.
7.15.1 [Attack methods and the impacts]
Unlike websites on the Internet, the MFP is connected to the in-house LAN and is mainly set up
and configured for the usage that is closed in the LAN. Therefore, it is usually difficult for
attackers on the Internet to access the MFP web management console and attack by exploiting
vulnerabilities. However, vulnerability measures on the MFP web management console are very
important, in consideration of misuses of web applications and unauthorized accesses to the
protected assets by insiders or attackers who intrude on internal networks, etc.
“How to Secure Your Web Site (5th Edition),” provided by IPA, categorizes issues
(vulnerabilities) to be considered when constructing web applications as follows, and presents
the measures.60 These measures against the vulnerabilities of web applications are essential
even for MFPs, and the development considering each vulnerability and to inform users of the
appropriate usages required.
1)
SQL injection
In the case that the MFP has a database server inside and manages the protected assets, the web
applications on the MFP in collaboration with the database prepares SQL statements based on
the input information. In the case that there is a problem with the preparations of the SQL
statements, there is a possibility that unauthorized uses of the database are caused by attackers
(e.g., unauthorized viewing of data, tampering and deletion of data, and unauthorized login by
authentication bypass, etc.).
Measures against such attacks are as follows:
Prepare all SQL statements by implementing placeholder.
In the case that the SQL statement is prepared by character string consolidation, correctly
configure the literals in the SQL statement using the API61 of the database engine for
escape processing, etc.
Error message should not be returned as it is.
Appropriate authority should be given to database accounts.62
2)
OS command injection
While OS commands may be unique on the MFP in some cases, there is a possibility that
unauthorized data viewing, tampering, deletion, or unauthorized system operations, etc., are
performed by unauthorized executions of OS commands of the web server from outside,
Vulnerabilities of mail header injection will not be mentioned, because they have less chance of being
used on the web management console of the MFP.
61 The same applies to the API provided by the framework and language being used in the applications.
62 Sharing only one database account that has a universal type of authority used to update or delete all
objects shall be avoided.
60
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depending on languages that have developed web applications, if input parameter checks of
web application are insufficient.
Measures against such attacks are as follows:
Avoid using the language function that can start the shell.
In the case that the language function that can start the shell is used, check all variables
that compose the argument, and execute only the processing that was previously
permitted.
3)
Uncheck of path name parameter/directory traversal
It may be a part of the OS command injection, but in the case when there are web applications
that directly specify the file name inside the web servers in the external parameters, there is a
possibility that attackers can specify arbitrary files when there is a problem in the
implementation of specifying the file names, and unintended processing may be performed by
web applications.
Measures against such attacks are as follows:
Avoid implementations that directly specify the file name inside the web servers in the
external parameter.
When a file is opened, specify a fixed directory, but the directory name should not be
included in the file names.
Appropriately manage the settings for access authority to the files on the web servers.
Check file names.
4)
Defects of session management
In the case when there are defects in the management and issuance of session IDs used for
maintaining login status of administrators and users on web applications of the MFP, there is a
possibility that attackers can illegally obtain session IDs of the administrators and users, who
are logged in, to gain access by impersonating the users.
Measures against such attacks are as follows:
Make session IDs difficult to predict.
Do not store session IDs in the URL parameters.
Add the secure attribute to the Cookie that is used for HTTPS communications.
After a successful login, start a new session.
After a successful login, issue the confidential information in addition to the existing
session IDs to check its value for each page.
Do not use the fixed values for session IDs.
In the case when session IDs are set to Cookie, be careful with the setting of the
expiration dates.
5)
Cross-site scripting
If there is a problem with the output processing to a web page, there is a possibility that the
website may be tampered with by embedding the script, etc., or that a Cookie stored by the user
browser may be obtained, etc. As a result of this, for example, session information may be
leaked.
Measures against such attacks are as follows:
Perform the escape processing to all elements being output to web pages.
When outputting the URL, permit only URLs that start with “http://” or “https://.”
Do not dynamically generate the contents of the <script> ... </ script> elements.
Make sure the style sheet is not captured from an arbitrary site.
Check the contents of input values.
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-
6)
Create a parse tree from the HTML text input, and extract only the necessary elements
that do not include scripts.
Eliminate the character strings that correspond to the scripts from the HTML text input.
Specify the character encoding (charset) in the Content-Type field in the HTTP response
header.
Add the HttpOnly attribute to the Cookie being issued to disable the TRACE method as
the prevention measures of Cookie information leakage.
CSRF (Cross site request forgeries)
In the case that there is no mechanism in the applications on the MFP web server to identify
whether or not the requests from the users logged in are intended requests by the users, there is
a possibility that malicious requests may be accepted via external sites. Having this structure of
web applications, the users who logged in may perform unexpected processing (such as the
execution of functions available only by the users logged in, or tampering with, and deletion of,
the protected assets) by the traps prepared by attackers.
Measures against such attacks are as follows:
Make the pages that execute processing accessible by the POST method, and
automatically generate the previous page to insert the confidential information into the
“hidden parameters,” and execute processing only if the value is correct on the execution
page.
Ask for entering the password again on the page immediately before executing the
processing, and execute the processing only if the password entered again is correct on
the execution page.
Check the Referer if the source link is correct, and execute the processing only when it is
correct.
When any important operation has been performed, automatically send to the email
addresses that are registered.
7)
HTTP header injection
In the web applications that dynamically generate the field values of the HTTP response header
of output responses to requests, by using parameter values passed from the outside, there is a
possibility that attackers will add an arbitrary header field to the responses, or create an
arbitrary body, and conduct attacks that may create multiple responses, if there is a problem in
output processing of the HTTP response headers.
Measures against such attacks are as follows:
Do not directly output headers, but use the header output API that is provided in the
language or execution environment of the web applications.
In the case that the header output API that properly processes the line feed cannot be
used, developers should implement the appropriate processing by themselves not to
permit the use of the line feed.
Delete the line feed for all the inputs from the outside.
8)
Lack of access control and authorization control
In the case that there is a defect in access control and authorization control of the web pages
that can only be accessed while users or administrators are logged in, for the applications on the
MFP web servers, there is a possibility that attackers can impersonate users or make
unauthorized accesses, etc., to the functions that are not permitted.
Measures against such attacks are as follows:
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The web pages that require defensive measures by the access control function should be
provided with the authentication function that requires confidential information input,
such as a password, etc.
Implement the processing of authorization control in addition to the authentication
function, and make logged-in users inaccessible by impersonating other users.
In addition to the above viewpoints, it is necessary to develop the web applications that have
taken basic measures; for example, measures to avoid malfunctions caused by the input of
unexpected values for parameters, such as unauthorized input of a value that is not in the radio
button or list box; or measures to avoid including the information in the messages that respond
to the errors that favor attackers, or to avoid outputting the trace information, etc.
As described in the references, the vulnerability that administrator authority can be obtained by
authentication bypass was published on the web management screen of a domestic MFP vendor
in 2012. The vulnerability of authentication CSRF is presented here as an example of the
vulnerability that existed on the web management console:
<Overview of web management console>
In this web management console, user identity authentication (including administrators, etc.)
and session management after login are appropriately performed at the top page, to provide
various functions according to the user authority. It is possible to encrypt accesses to the web
management console by SSL/TLS. However, it is difficult in general to obtain communications
contents by wiretapping in this case.
<Main functions provided by the web management console>
- Users
User information management function, inbox management function, etc.
- Administrators
Network settings function, HDD encryption function, HDD bulk deletion function,
backup and restore function, security mode settings function, etc.
- Maintenance personnel
Firmware update function, HDD format function, password initialization function. etc.
As described above, identity authentication, session management, and encryption of
communications have been properly performed for this web management console. However,
there was a possibility that the various functions, which only administrators with identity
authentication or authorized administrators could execute, may have been invoked and executed
by attackers, because no measure was taken against vulnerabilities of CSRF as shown in Figure
7-15. In this case, instead of the CSRF method to create another website to make administrators
conduct unauthorized acts, the attackers sent PDF files to administrators to make them perform
arbitrary operations by exploiting the function of PDF viewer software, for which JavaScript is
automatically executed when administrators view the PDF files.
By this attack, there was a possibility that all functions provided for the MFP in the web
applications would have been executed by the attackers if certain conditions were met; for
example, the leakage of user information, exposure or damage of registration data, unauthorized
execution of administrator functions such as HDD bulk deletion, etc., security mode resetting,
rewriting of unauthorized firmware, etc.
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Successful
execution of
security
functions
Figure 7-15 Example of attack by CSRF
7.15.2 [Causes and discussion]
The cause that makes the attack on the vulnerabilities of CSRF possible is that the measure
against cross-site request forgery as described earlier is not performed (e.g.: verifying on the
MFP using other identification ID than the session ID, such as Token, etc.). In the case when
various functions, which only the users who are authorized or have identity authentication can
execute, are provided, measures against vulnerabilities of CSRF are required.
The vulnerabilities, such as CSRF in the web applications that are described in this section, may
be confirmed to some extent by vulnerability inspection tools for the general websites that are
covered in Section 7.11.3. Since the session management mostly is not confirmed by the tools,
it is necessary to ensure that the session value is actually checked by manual inspection and
used, or that the implementation is not predictable or reusable with the session value, etc.
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7.15.3 Measures
[Operation guide]
1)
2)
3)
In the case that vulnerability information about the web management console is
provided by vendors, etc., apply patches to the MFP provided or change the browser
settings, etc., in consideration of the scope of the impact.
Access the web management console by encrypted communications, such as SSL/TLS,
etc.
Follow the security guidelines of the MFP to setup the MFP on the network where the
security can be ensured (in case there is a guideline).
[Development guide]
4)
5)
Develop web applications of the MFP, referring to the documents, etc., in the
references.
Always check the latest vulnerability information related to the relevant applications,
such as languages that are used in the web applications or on the web servers
implemented on the MFP, and notify users. In the case of vulnerabilities having an
impact on the proprietary MFP, provide patches or firmware that correspond to the
vulnerabilities, in addition to giving notice about them.
[Verification guide]
6)
7)
Check with the web servers that are implemented on the MFP and script languages that
are used in the web applications as to whether the known vulnerabilities apply.
Make sure there is no vulnerability in the web applications using the vulnerability
inspection tools and manual inspections together.
7.15.4 References
Date of publication
March 2012
Source
IPA: How to Secure Your Web Site (Revised 5th Edition)
http://www.ipa.go.jp/security/vuln/websecurity.html
Notes for creating a secure web site and checklist for measures are summarized.
Frequently updated
OWASP (The Open Web Application Security Project)
https://www.owasp.org/index.php/Category:OWASP Guide Project
Guidelines with notes etc., for developing web applications. In addition to the above, more useful
information, such as test guides, etc., is provided on this site.
The Common Attack Pattern Enumeration and Classification (CAPEC)
http://capec.mitre.org/index.html
Various attack patterns are simply categorized and summarized.
Frequently updated
April 2011
CVE-2011-1531
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-1531
Vulnerabilities of EWS are reported.
April 2011
CVE-2011-1533
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-1533
Vulnerabilities of Cross-Site scripting are reported.
April 2012
CVE-2012-1239
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-1239
Vulnerabilities of possible authentication bypassing are reported.
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7.15.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
Assuming that there is a vulnerability of CSRF in the session management of the management
web applications, an attack in which attackers make administrators execute unauthorized
instructions by using CSRF is discussed here. It is assumed that the confidentiality, integrity,
and availability are impacted overall by making the administrators execute the backup and
restore function on the MFP, including the protected assets.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
7.9 (Danger)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.16 Problems from the misuse of web-based maintenance functions
Attackers can illegally obtain the information inside the MFP and information of other systems
related to the MFP, by exploiting these maintenance interfaces on some MFPs that provide
web-based maintenance functions.
7.16.1 [Attack methods and the impacts]
The maintenance functions of the MFP include diagnosis of the remaining amount of toner and
number of copies, diagnosis of failures, or replacement and repair of defective parts, in general.
Among these functions, the following functions are used to replace a failed hard disk:63
1)
2)
3)
The function to back up document files and address books in bulk inside of the MFP.
The function to overwrite document files and address books in bulk inside the MFP
from certain files.
The function to delete and perform overwrite deletion of documents and address books
in bulk inside the MFP.
The function to back up document files, described in 1), can retrieve documents in bulk that are
stored on the hard disk inside the MFP to outside the MFP. This function is needed to replace
with a new HDD when the HDD inside the MFP has failed.
The function that overwrites document files inside the MFP with certain files, described in 2),
recovers the contents of the HDD using the backup data of the HDD saved in 1), and is called
“restore.”
The function to delete and perform overwrite deletion of documents and address books in bulk
inside the MFP, described in 3), is used to delete the contents of the hard disk that needs to be
replaced and disposed of. It is also used to prevent the information inside the MFP from leaking
to third parties at the time of disposal of the MFP.
The interfaces inside the MFP as described above provide functions to perform maintenance
remotely via networks, because they should be transferred to where the MFP is set up in order
to perform the maintenance of the MFP.
In general, maintenance functions are executed from a terminal on the network in the
organization as on a maintenance terminal shown at the top left in Figure 7-16. In the case of
using the external maintenance services provided by developers or maintenance personnel,
communications for remote maintenance through a network outside of the organization, such as
in the upper-right corner of Figure 7-16 are performed. Maintenance interfaces directly
connected to the main unit of the MFP may also be used in some cases.
63
These functions are provided to users as administrator functions on some MFPs. However, it is assumed
that these functions are implemented on the MFP as maintenance functions in this section.
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Figure 7-16 Example of method for accessing the maintenance interfaces (http)
As shown in the figure, there are multiple paths for the maintenance functions. Among these, it
is assumed that the maintenance personnel use the web-based maintenance functions of the
MFP in the users’ intranet from a web browser on the maintenance terminal.
Figure 7-17 below shows an example of an attacker, who is a user, exploiting a maintenance
person’s session without authentication by performing CSRF against the web browser of the
administrators, who uses the web-based maintenance functions, and making the maintenance
person delete the data in the MFP.
The maintenance person opens a page of the maintenance functions after obtaining
authentication on the maintenance website. Maintenance functions, such as data backups inside
the MFP, can be executed without following the authentication procedure by injecting
JavaScript code to open a specific URL on the administrators' browser as indicated in red lines,
while the browser’s maintenance function page is opened.
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Figure 7-17 Example of a sequence for exploiting a maintenance interface using CSRF
The success of this attack method requires some conditions. A major assumption is that the
session management function that can counter CSRF is not built into the maintenance website.
Then, the page should remain open for use by maintenance personnel for maintenance functions,
or there should be an insufficiency of the maintenance website, such as not managing logoffs,
etc., to leave the session information on the maintenance terminal. On that basis, it is necessary
to induce a browser on the maintenance terminal to a specific site to download the attack code.
In addition, it is needed that the attacker is able to guess the command system of the
maintenance website.
In terms of attack opportunities, it is even less than the CSRF to the users or administrators as
described in Section 7.15. However, it cannot be said that there is no possibility that the
conditions, behaviors or works of the maintenance personnel are visible.
In the maintenance works from a remote location, there are methods for the MFP to access the
maintenance site to set up a dedicated connection, such as VPN, in a simple way. They are
readily available on the user networks with IP address converting or firewall established.
7.16.2 [Causes and discussion]
When a defective part of the main unit of the MFP is replaced, maintenance interfaces of the
main unit of the MFP perform important functions, such as backing up the internal information.
Maintenance personnel of the MFP vendors or contractors perform maintenance works in
general, but some maintenance functions may be disclosed to users for the convenience of users.
In some cases, some dedicated maintenance software is disclosed to some users.
Although these maintenance functions are convenient, the functions for HDD replacement and
disposal of the MFP are sometimes not clearly stated in the operation manuals of the MFP.
Maintenance personnel of the MFP are responsible for parts replacement, but users need to
back up the HDD contents when the HDD is replaced, because the users have responsibility
over the HDD contents, including protected assets, etc. It is assumed, however, that the
maintenance personnel may backup and restore the HDD contents upon replacement in this
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research. In many cases, users do not have knowledge about the replacement of the HDD, or the
methods or cautions for backup and restore, in general. It is a great benefit for users to have
maintenance personnel take care of them.
In order to meet the needs of users who want high availability of the MFP, it is assumed that the
maintenance functions may be opened outside via the networks. However, if the maintenance
functions are exposed to the internal networks or to the outside, they would become targets for
attackers. If they are the maintenance functions of the web applications as described in this
section, they should be provided with a strong defense against much vulnerability that is
described in Section 7.15.
If the convenience of the MFP increases in this way, threats also increase at the same time. The
possibility to be intruded increases if the maintenance interfaces, in particular, are opened not
only to the dedicated interfaces of the main unit of the MFP but also on the network. When
third parties, such as maintenance personnel, take care of the HDD contents, the kinds of
protection or measures that should be taken may become issues.
Not all MFP vendors are necessarily providing the backup function at this point. However,
some measures to be taken are considered to use the backup function in order to continuously
use the advanced MFP functions by shortening the service downtime for MFP users. The main
measures include specifying the scope of access by function as of local maintenance functions,
backup data protection by encryption, etc., for the important maintenance functions, such as
backup and deletion.
7.16.3 Measures
[Operation guide]
1)
2)
Disable the maintenance functions from outside if they are not necessary, depending on
the operating environment.
In cases when there are multiple maintenance functions, which are operable outside the
maintenance functions using the web applications, disable the maintenance functions
that are using the web applications.
[Development guide]
3)
4)
Dissemination of information to users of the risks due to enabling the maintenance
functions externally.
Implementation of secure maintenance functions and the security default settings.
[Verification guide]
5)
In case the maintenance interfaces are implemented by web servers, examine whether
the measures against the vulnerabilities are implemented as described in Section 7.15,
as with the case of the normal web console.
7.16.4 Reference
Date of
publication
June 2009
Source
CWE-352 Cross site request forgeries
http://jvndb.jvn.jp/ja/cwe/CWE-352.html
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7.16.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
As assumed in this section, when the maintenance personnel use the web-based maintenance
functions from the intranet, it is assumed that an attacker accesses all the protected assets on the
MFP by executing functions, such as backup and restore by CSRF, together with the
maintenance personnel.
- It should be the environment where the measures in the operation guide as above are not
taken.
- It should be the environment where attackers can check the behaviors of the maintenance
personnel.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
7.9 (Danger)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Overall impact
Overall impact
Overall impact
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7.17 Problems of using external authentication
In order to perform the appropriate access control for the protected assets inside the MFP, the
MFP has a user identity authentication function. Some MFPs are implemented with the
“external authentication” function to perform access control based on the results of the
authentication function undertaken by the external authentication servers. In the case that the
user identity authentication system is already configured in the office where the MFP is
introduced, this external authentication function is considered to be used quite often from the
viewpoint of convenience by the centralized user management. In this case, users are required
to take measures, such as applying appropriate patches in accordance with the operational
environment, etc., against several vulnerabilities64 that exist in the external authentication
servers. However, that is not the only viewpoint in terms of vulnerability. Vulnerability that
exists inside the MFP mechanism itself, which uses the external authentication, should also be
concerned.
7.17.1 [Attack methods and the impacts]
In this section, the mechanism using Microsoft Active Directory, which is implemented as
many cooperation destinations of the external authentication of the MFP, is explained. Other
than Active Directory, there are some external authentications of the MFP that can work with
the NTLM,65 which was used by Windows NT4.0 or earlier. However, the NTLM has old
specifications, and they have been known to be vulnerable to man-in-the-middle attacks. This
vulnerability can also be applied in the case that the NTLM is used for user authentication of
the MFP. Therefore, an attack method in the case of using the authentication mechanism of the
Active Directory, which have no problems in general use, is discussed in this section.
Supplement: Overview of Kerberos authentication
A mechanism called Kerberos is used for user authentication of Active Directory. As shown in
Figure 7-18 “Kerberos authentication image,” Kerberos consists of user terminals, servers that
the users want to access, and KDC (Key Distribution Center). The KDC holds private keys to
the user terminals (calculated from the password) and all private keys to the servers. Kerberos
authentication using the KDC is applied as a means to share a session key for users to perform
secure communications with the target servers. An overview of Kerberos authentication is
described as follows:
For example, vulnerability in the backdoor to Microsoft Active Directory is known. Directory server
information is not necessarily reliable.
65 Windows NT LAN Manager authentication
64
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KDC key management
User identity
authentication
(I) Request for connection
OK
(II) Ticket
Servers
OK
(III) Access permission request
Permit access
User terminals
(IV) Encrypted communications by session key
Protected
assets
Figure 7-18 Kerberos authentication image
1)
2)
3)
4)
When a user wants to access the server from the user terminal, procedures give
authentication to the user to ensure that the private key is recognized by both the KDC
and the user terminal. The private key can be obtained by the calculation of the user’s
password at this time.
The KDC sends a ticket to interact with the server to the user terminal of the user who
is authenticated. Encrypted information by the server key is added to the ticket.
The user terminal verifies and sends the ticket to the server. The server checks the
ticket, determines that the user is given permission by the KDC by decrypting it with
its own private key, and gives the user “access permission.”
Then, encrypted communications between the user terminal and the server are
performed by the session key, which was contained by encrypting in the ticket.
Unauthorized access to the protected assets of the MFP
In this mechanism, the attack on the authentication for MFP users is examined. As a result, the
verification experiments confirmed that attackers can access the protected assets of the users,
whom they are impersonating without knowing their passwords, if environments have access to
the networks connected to the MFP.
This attack method is not publicly available at the moment. It is not really an unrealistic
approach, and requires no special high attack potential.
Therefore, the details of the attack methods and their causes are omitted in this report due to the
concerns of creating more opportunities for attacks by publishing such attack method details, in
cases that there are vendors or models that do not take measures.
7.17.2 Measures
Although the details of the attack methods are omitted, the verification experiments confirmed
that the attack would successfully gain unauthorized access to the protected assets if the
“external authentication” mechanism on the MFP is used. When using the external
authentication function, measures that should be considered to prevent such attacks are
presented.
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[Operation guide]
1)
The MFP should be operated in an environment where monitoring of the existence of
services running on the servers and monitoring of unauthorized ARP packets, etc., are
available.
By checking the vulnerability information of the OS and services provided by the
servers related to the external authentication, take measures as necessary, such as
applying patches, etc.
2)
[Development guide]
3)
Security functions when accessing protected assets via the external authentication shall
be added to ensure the security equivalent to the main unit authentication, even in case
of using the external authentication.
[Verification guide]
4)
Conduct intrusion tests if there is a possibility of attacks by comprehensively
identifying attacks inside the MFP using an external environment to the MFP.
7.17.3 References
Date of publication
January 2012
May 2004
December 2011
June 2011
February 2011
Source
A Backdoor in the Next Generation Active Directory
http://www.exploit-db.com/wp-content/themes/exploit/docs/18415.pdf
The commentary article on the vulnerability of the backdoor hidden in Microsoft Active
Directory
NTLM authentication and the man-in-the-middle attack
http://www.st.rim.or.jp/~shio/csm/ntlm/
Descriptions of the authentication servers by NTLM that can be easily impersonated
CVE-2011-3406 Active Directory Buffer Overflow Vulnerability
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-3406
Vulnerability that authenticated users can execute arbitrary commands due to buffer
overflow
CVE-2011-1264 Active Directory Certificate Services Vulnerability
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-1264
Vulnerability related to XSS of Active Directory Certificate Services website
CVE-2011-0040 Active Directory SPN Validation Vulnerability.
http://web.nvd.nist.gov/view/vuln/detail? vulnId=CVE-2011-0040
Vulnerability of DOS by unauthorized requests
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7.17.4 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
It is assumed that it is an environment where the details of the attack methods that are omitted
are successfully conducted.
- It should be the environment where the measures in the operation guide as above are not
taken.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
5.4 (Warning)
Possible attacks from neighboring
networks
Moderate
No authentication operation required
Partial impact
Partial impact
Partial impact
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7.18 Problems of malware infected files mixing into the MFP
Malware is a general term for a program, etc., that runs in a target device, and is created with
the intention of producing actions that are unauthorized or that will cause harm. Malware,
mentioned in this report, is a program that causes the unauthorized leakage and tampering of
the protected assets against the infected MFPs and user terminals. A typical example of attack
by malware against the MFP is uploading of unauthorized firmware with malware built-in,
using the firmware update function as described in Section 7.7. Additionally, the propagation of
malware to the user terminal connected to the running MFP that is infected is also assumed. The
possibility of the malware stored in the MFP being propagated to the user terminals is discussed
in this section.
7.18.1 [Attack methods and the impacts]
Possible methods of mixing the malware into the MFP are as follows:
-
Upload firmware with malware built-in, using the firmware update function illegally.
(Section 7.7)
-
Upload programs with malware built-in, using the file update function by PJL described in
Section 7.14.
-
Upload any unauthorized programs using the maintenance interface function that is
obtained by the methods described in Section 7.5.
-
Save the malware inside the MFP by taking advantage of the vulnerable SDK described in
Section 7.9.
It is assumed that the document files attached with malware are stored in the email queue to be
sent to users by illegally operating the MFP by means of any of the above.
The method to propagate the malware stored in the queue to the user terminals uses general
MFP functions. Recent MFPs have a function to attach images received via fax or scanned by
the MFP to emails automatically, and to deliver to the user terminals.66 Such functions can be
executed as any users, or instructions can be executed directly using unauthorized methods.
Buffer overflow, etc., can be used by the PJL of Section 7.14 for executing the instruction. In
addition, instructions may be executed by the auto-run function using a USB that is modified
illegally.
In order to guide users to execute the malware attached to emails, an attacker finds “Subject” or
“Sender” trusted by the users, and adds them to create fake emails. If users are
security-conscious, they can suspect fake emails from the subjects or the senders, and it is
unlikely that they execute unauthorized attached files. However, in the case of receiving emails
with familiar subjects and with file attachments from the normally-used MFP as a sender, users
may open (execute) the attachment with relatively little suspicion.
66
The MFPs of domestic vendors have deployed a function to distribute document data as email
attachments, called Scan to Mail or Scan to E-Mail.
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(I) Store emails
with malware
attached in the
email queue
User terminals
(II) Scan to Mail
Sending to registered
users
(III) Infection by opening
the attached files
Figure 7-19 Image of malware propagation to the user terminals from the MFP
Supplement: Malware from which the MFP is impacted by attacks
While it is considered that there are attacks of malware propagation in the offices of the users
having the MFP as a medium of infections as described in this section, there was a report that
the MFP is impacted by unauthorized operations of user terminals, because the user terminals
are infected with malware. In 2011, the American Chamber of Commerce became a target for
targeted attack. In addition, a printer virus that prints a large volume on the MFP from the
infected user terminal became well-known in the summer of 2012. It is generally difficult for
the MFP functions to prevent such a case of impacts in the normal scope of operations of the
MFP that is connected to the infected user terminal, by receiving a command for a large print
job.
Supplement: Malware the main unit of the MFP is infected with
Next, there is also a possibility that MFPs themselves may be infected with malware that are
mixed into the MFP (OS and firmware on the MFP are impacted). The MFPs may sometimes
be infected with scripts that are attached to the documents, in addition to rewriting to the
unauthorized firmware. In 2003, an MFP using a Windows-based embedded OS was infected
with malware. In other words, the assumption that the MFPs are invisible from the external
networks and that administrators do not perform unauthorized actions no longer holds, just for
malware existing in one user terminal in the office.
Some public documents of MFP vendors that can be confirmed as of 2012, describe that the OS
that is installed on the MFP is too minor to be infected with malware, as is shown in Figure
7-20 “Example of security concepts of MFP vendors” by some MFP vendors67
However, for example, in the case that a document attached with a script in which malware is
embedded, is saved on the MFP, and the document is opened from the browser of the MFP
panel, there is a possibility that the firmware or OS on the MFP may be impacted by malware if
there is a vulnerability in the applications on the browser. Some MFPs are also confirmed to
have had general-purpose embedded Linux as their OS in recent years. It may be desirable for
developers to implement functional measures, such as script deletion from the document files,
or not enabling it on the MFP, etc.
67
A public document on the security concept of the MFP vendors is presented in the references.
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…since the majority of viruses and worms exploit vulnerabilities in Windows-based
computers. vendor name MFPs use non-standard operating systems other than
Windows. Consequently, they are immune to these viruses and worms.…
Figure 7-20 Example of security concepts of MFP vendors
7.18.2 [Causes and discussion]
Some MFPs have a function to save the data received as fax or scanned as PDF files, Microsoft
Word, or Microsoft Excel formats, and to send them to users. By exploiting this function, it may
be possible to send the documents with malware built-in in the form of attachments to emails to
the user terminals. However, it is impossible to embed the script in the data converted into a
PDF file, etc., to be saved, by using faxing or paper for inputting data in normal usage. In order
to make this attack successful, it is assumed that the MFP should be already in an unauthorized
condition; for example, a user who becomes an attacker should take procedures, such as saving
the document data with a script directly into the email queue by using an unauthorized
procedure that is prepared beforehand.
Measures that users should take are to maintain a policy that emails from the MFP which have
unfamiliar files attached shall not be opened, and to make the policy known to everybody. As a
measure in case the attached files have been opened, it is required to maintain applications,
such as PDF reader, on the user terminal as versions without vulnerabilities all the time.
7.18.3 Measures
The function to send document files on the MFP automatically to a user terminal, etc., has the
purpose of user convenience. This vulnerability does not depend on functional vulnerability of
the MFP, but on the security policies and their operations in the offices of the users. Measures
that users should take against the described attacks are explained here.
[Operation guide]
1)
2)
3)
Operate a policy that emails even from reliable senders shall not be opened, if there is
an unexpected attachment.
Maintain applications used in the offices of the users all the time as versions that do
not have any problem using a reference to vulnerability information of the
applications.
The formats that are not used to save the scanned or faxed images should be OFF in
the MFP settings.
The development guide can suggest the implementation of the functions that the scripts
embedded in the document data are automatically deleted, when sending the document data to
the user terminals from the email queue on the MFP, but such functions could be disabled by
rewriting the unauthorized firmware in some cases. As a supplement, the following measures
can be taken against impacts on the MFP by malware. However, it is necessary to respond by
taking functional measures described in each section, against malware mixing into the MFP
through unauthorized procedures using the maintenance functions.
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[Development guide]
4)
5)
6)
Confirm that there are no vulnerabilities that have impacts from malware in the
firmware or software that control communications of the MFP, using source code
analysis tools, etc.
Make sure of the implementation that the scripts attached to the documents are not
executed when verifying documents, etc., on the MFP operation panel.
Verify if the remodeling of published attack code has no impact on the OS that the
MFP is implemented.
[Verification guide]
7)
8)
Examine the applications running on the MFP. For example, if the MFP has a browser
installed on the panel, the browser or applications which operate by linking should be
examined if they have no impact on the protected assets of the MFP by exploiting
them.
Ecamine whether there is any impact on the MFP using the published attack code for
the OS of the same systems.
7.18.4 References
Date of publication
February 2012
June 2012
May 2012
February 2011
December 2011
June 2012
Source
MULTIFUNCTION PRINTER VULNERABILITIES
http://msisac.cisecurity.org/resources/reports/documents/A-0012-NCCIC-130020120223MFPVulne
rability.pdf
Vulnerability report including malware mixing related to MFP
Malware attack spread as email from your office's HP scanner
http://nakedsecurity.sophos.com/2012/07/24/malware-hp-scanner/
Topic that malware is sent from the scanner to users
PostScript: Danger Ahead? !
http://hackinparis.com/slides/hip2k12/Andrei-PostScript%20Danger%20Ahead.pdf
Overview of methods to store malware on the MFP and propagate it
Article about the attack via USB, which is published in BlackHat in 2005
http://news.mynavi.jp/articles/2005/08/03/blackhat4/index.html
Methods which cause the USB to be mistaken as a device that automatically performs
China Hackers Hit U.S. Chamber
http://online.wsj.com/article/SB10001424052970204058404577110541568535300.html
Article about the incident that U.S. Chamber of Commerce was attacked from China conducting
unauthorized printing
Printer virus
http://blog.trendmicro.co.jp/archives/5415
Article about the printer virus that was epidemic in 2012
October 2007
Likewise, a “PDF virus” arose to a said vulnerability of Adobe
http://itpro.nikkeibp.co.jp/article/NEWS/20071024/285333/
The file infection by attached files by taking advantage of the vulnerability of PDF
July 2010
The SHARP Security Suite
http://files.sharpusa.com/Downloads/ForBusiness/DocumentSystems/MFPsPrinters/Security/cop
dow securitybro.pdf
A claim that MFP OS is less likely to be susceptible to malware
Comment on security by HP
http://h20424.www2.hp.com/program/wdyhts/enterpriseprint/sg/en/pdfs/whitepaper/HP security
solutions.pdf
A claim that MFP OS is less likely to be susceptible to malware
Lexmark technical white paper (Security)
http://www.lexmark.com/vgn/images/portal/Security%20Features%20of%20Lexmark%20MFPs%2
0v1 1.pdf
A claim that MFP OS is less likely to be susceptible to malware
July 2006
February 2006
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April 2009
October 2003
Samsung “MFP Security Overview”
http://www.samsung.com/us/it_solutions/healthcare/_pdf/5_MFP%20Security%20Overview%20Re
v0A.pdf
A claim that MFP OS is less likely to be susceptible to malware
Handling of vulnerabilities and computer viruses in Windows
http://www.fujixerox.co.jp/company/news/release/2003/0919 msblast.html
Example of the installed OS on the MFP that has been affected by malware
7.18.5 Seriousness and attack potential evaluation (reference value)
[Attack assumptions]
An attack on an MFP infected by malware described in the supplement is discussed here. It is
assumed that the MFP is infected by putting malware on the office network, taking advantage
of the vulnerability of any code that is executable on the embedded OS of the MFP, in the same
manner as malware, in which the MFP with embedded Windows OS generated in 2003 has
been affected. It is assumed that the malware that has a function to set up a backdoor using the
vulnerability is published.
- It has to be an environment that does not take the above measures.
[Scoring]
CVSS 2.0 Base value:
Attack source category
Complexity of attack criteria
Pre-attack authentication
requirement
Confidentiality
Integrity
Availability
8.3 (Danger)
Possible attacks from neighboring
networks
Low
No authentication operation required
Overall impact
Overall impact
Overall impact
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8. Other security measures
8.1
Problems of manufacture by developers and the time of delivery
For the attack methods against each vulnerability described in Chapter 7, the attacks on the
MFP design assets or on the manufacturing and delivery process are based on the assumption
that “the security in the manufacturing and delivery process are ensured by developers.”
Aspects of the attacks for these processes that should be ensured by the developers are
explained here. If there is no sufficient security ensured in the manufacturing and delivery
process by the developers, the attacks would succeed by an easier means without the attack
procedures as described in Chapter 7. For example, for an attack that uploads unauthorized
firmware from the maintenance interfaces of Section 7.7, reverse-engineering needs to be
performed by using special hardware from the binary that is open to the public, because there is
no source code of the firmware in the hands of an attacker. However, the attack will become
much easier without reverse-engineering, if the attacker has directly obtained the source code
by applying social engineering methods to the developers, removing design assets taking
advantage of insufficient management, or exploiting the management system holes during the
manufacturing and delivery process, etc. In addition to those, the leakage of internal documents
with procedures for access to the confidential interfaces described in Section 7.5, may be
possible during manufacturing and delivery process by the developers. In order to ensure
security at the development sites as well as during the manufacturing and delivery process until
MFPs are provided to users, the developers should be fully aware of the possibilities of the
attacks during such procedures, and should ensure security by designing appropriate operation
methods for each process.
8.2
Information provision to users through guidance
It is assumed that users may handle the vulnerabilities described in this section by the MFP
settings, security policies, or a combination of both. In such case, developers shall provide
precautions to users of more reliable ways, such as specifying in the guidance about the settings
and operations in order to maintain the MFP in a secure condition; for example, cases when
users should set up for the log records, or what users should observe to operate the MFP in
secure conditions.
8.3
Outbound measures on the MFP
The outbound measures discussed in this section are measures against malware infection of
client PCs and servers connected to the networks in the offices. Moreover, they are intended to
prevent the malware infection from spreading from the office to the outside in case they are
infected. As outbound measures, in addition to the malware expansion to the outside, the
leakage of the protected assets to the outside, which is the ultimate goal of using malware,
should be considered.
The ‘Design and Operational Guide to Protect against “Advanced Persistent Threats,” Revised
2nd Edition,’68 by IPA suggests the measures and implementation methods for each point
classified by performing the outbound measures mentioned above, from the viewpoint of
detecting the backdoor and preventing malware from spreading as follows:
68
http://www.ipa.go.jp/security/vuln/documents/newattack.pdf
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1)
Design of service communications path
- Setup the cutoff rules for outward communications of the firewall.
- Monitor the cutoff logs of the firewall.
2)
Design an http communications detection function that imitates the communications
patterns of browsers
- Cut off the http method for usage of backdoor communications.
3)
4)
5)
6)
7)
8)
Design of sensor cutoff for the internal proxy communications (CONNECT
connection) of RAT69
Monitor by the internal proxy log using the features of the establishment of the
CONNECT communications of RAT.
Design of physical separation of direct internet connection at the most important points
Design VLAN, etc., so as not to directly connect to the internet at the most important
points.
Protection of critical attack target servers
Protect the management segment to manage AD.
Apply patches for the AD services that are visible from users.
Design of VLAN network physical separation using switches, etc.
- Design the user segment and the management segment separately.
Detection of infection activities due to capacitive load monitoring
- Perform anomaly detection in log capacity or load on switches, etc., to cooperate with
the security department.
Limited design of attainment scope of P2P
- In addition to measures in 3) and 4), design the network for the purpose of eliminating
unnecessary RPC70 communications.
As described in Section 7.18, the MFP has a possibility of becoming a source of malware
infection, and shall be managed by outbound measures as much as the other servers and client
PCs in the offices. It also depends on the setup environments of the MFP, but some paths are
directly connected to the external lines without a firewall, such as via fax line. The MFP that is
infected with malware may transmit the protected assets to the outside by using those lines. In
the case of performing outbound measures, such measures need to be taken to the lines that
cannot be managed by a firewall, etc.
Remote Access Trojan/Remote Administration Tool. It is a tool to remotely manipulate the systems that
are intruded upon and used for incubation activities and theft activities, such as Poison ivy and Gh0st
RAT, etc.
70 Remote Procedure Call. It is a function to call the services that are running on a remote computer
connected to the networks, to request processing. It has a function to assign a new port dynamically upon
connecting to use it.
69
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9. Discussion of the vulnerabilities
related to new functions
Research Report on the Security of MFPs
9. Discussion of the vulnerabilities related to new
functions
In recent years, MFP vendors have developed new services, such as implementation of
applications to smartphones and tablets, which were deployed initially to client terminal PCs,
and seamless document management in conjunction with the cloud environment, etc. These
services are intended to improve convenience for users, but are not intended to add new data
workflows for the MFP usage described in Chapter 4. Smartphones and tablets are one of the
user terminals, and the cloud computing is an extension of the communications system.
However, for example, in addition to the external authentication in the cloud computing,
authentication cooperation of the cloud service using the authentication information is
performed. Therefore, the viewpoints regarding a new vulnerability in authentication
cooperation are the focus in this chapter and are discussed, including the impacts of the
deployment of the cloud environment. More specifically, the targets are the services that are
developed for the corporations, and the services that securely store data in the cloud in
coordination with authentication by Active Directory that is used in the external authentication
described in Section 7.17, and output from the MFP at the company branches or other hubs, are
the subject matter.
There is no vulnerability that the MFP can handle functionally, because this chapter is not a
description of the attack procedures for the MFP provided by the vendors or the related client
software. Attack procedures related to the authentication cooperation of Active Directory and
the cloud services that are generated by the published implementation deficiencies of SAML
are described as a reference when users consider the use of the MFP in coordination with the
cloud environment.
9.1
Problems of the implementation deficiencies of SAML
There are two main technical points of view to ensure security in the cloud environment. One is
to ensure the confidentiality and integrity of the protected assets stored in the storage on the
cloud, and the other is the appropriate user authentication.
For the protected assets that are stored in the storage, it is common to use a method to realize
the confidentiality and integrity well-balanced in such ways as ensuring the confidentiality by
encryption, ensuring the integrity by redundant use of parity disks, and ensuring quantitative
security using a secret distributing method. Actually, many cloud businesses accommodate
services with such technical methods built-in.
For authentication, SAML71 is well known as a technique to achieve cooperation with user
authentication (single sign-on) by Active Directory that is operated in companies. In 2002,
SAML 1.0 version was approved as an authentication cooperation technology, and is currently
introduced in cloud businesses such as Google, etc.72 Standard procedures of the authentication
cooperation of SAML 2.0 are shown in Figure 9-1.
71
72
Security Assertion Markup Language
There are technologies, such as WS-Federation and OpenID for consumers as well, but they are not
mentioned in this report.
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9. Discussion of the vulnerabilities
related to new functions
Research Report on the Security of MFPs
(III) User
authentication
Authentication servers
of the companies (idP)
(II)
(IV) Assertion
(I) Connection request
Cloud businesses
(II) Authentication redirect
User terminals
(V) Assertion
Access to storage
Figure 9-1 Image of authentication cooperation between Active Directory and cloud businesses
When a user accesses the protected assets on the cloud from a user terminal, the authentication
request is redirected to the in-house authentication server (an authentication server called idP in
coordination with Active Directory) during the access (from (I) to (II) in Figure 9-1). The
authentication server issues the Assertion for the user (from (III) to (IV) in Figure 9-1). The
user accesses the services on the cloud using the Assertion, which enables access to the
protected assets as an authenticated user on the cloud through the verification of the Assertion
((V) in Figure 9-1).
9.1.1 [Attack methods and the impacts]
In this section, an explanation is given for an attack by an attacker who takes advantage of the
vulnerability73 of implementation deficiencies of SAML to access the protected assets of a user
on the cloud by impersonating the user who performs authentication cooperation as described
above. This attack uses the man-in-the-middle (MiM) attack at the network level. The attacker
manipulates the packets, pretends to be a cloud to the user terminal, and obtains authentication
as a user on the cloud by pretending to be the user towards communications from the cloud, so
that he/she can access the protected assets of that user. Originally, SAML was a set of protocol
specifications that can prevent MiM because an Assertion received from the idP and sent to the
cloud in (IV) and (V) of Figure 9-2 includes identification information of the users and access
points. Figure 9-2 However, this attack would be successful using SAML, which is
implemented in the cloud services, because the measure taken against the MiM is incomplete as
a result of the simplification. Because it is required to perform the MiM when arbitrary user is
performing authentication works to access the protected assets on the cloud, there may be a
small chance for attacks, but this attack itself is not difficult if scripts, etc., are prepared.
73
http://cve.mitre.org/cgi-bin/cvename.cgi?name=2008-3891
197
9. Discussion of the vulnerabilities
related to new functions
Research Report on the Security of MFPs
(III) User
authentication
Authentication servers
of the companies (idP)
(II)
(IV) Assertion
User terminals
(I)
(I)´
(II)
(II)´
(V)
(V)´
Cloud businesses
Access
Figure 9-2 Image of unauthorized authentication by MiM
9.1.2 Measures
Measures that users should take against attacks described in this chapter are explained.
[Operation guide]
1)
2)
3)
Confirm that the protected assets that are stored in the storage of cloud services are
stored in a secure manner, such as with encryption and secret sharing.
Confirm that the data stored in the storage of cloud service is dispersion-managed, and
is assured safety even at the time of failure.
Confirm that the cloud services are not providing an implementation that is vulnerable
to attacks, such as MiM, in authentication cooperation between users and the cloud
services.
Items that should be considered when using the cloud services are, for example, listed on the
Open Government Cloud consortium website. When using the cloud services regardless of the
cooperation with the MFP, it is desirable to read it in advance in order to understand the various
risks due to the use of the cloud services.
9.1.3 References
Date of publication
January 2012
April 2012
January 2011
Source
SHARP CLOUD SOLUTION
http://www.sharp.co.jp/print/solution/cloud/
List of services that provide printing on the MFP in the convenience stores, etc., from a
variety of user terminals
Article from PageScope Mobile of Konica Minolta
http://www.konicaminolta.jp/about/release/2012/0403_02_01.html
Article on the MFP driver and client software for smartphones and tablets
Learning the authentication cooperation and account management technology required
for the era of cloud computing
http://enterprisezine.jp/iti/detail/2754
Article describing account management and single sign-on
198
9. Discussion of the vulnerabilities
related to new functions
Research Report on the Security of MFPs
November 2011
How to choose the cloud by learning from the security incidents of Dropbox and Google
and cloud security guidelines
http://web-tan.forum.impressrd.jp/e/2011/11/09/11249
Appropriately
Updated
OASIS Security Services (SAML) TC
https://www.oasis-open.org/committees/tc_home.php? wg_abbrev=security
Website of SAML technical committee
October 2008
Formal Analysis of SAML 2.0 Web Browser Single Sign-On: Breaking the SAML-based
Single Sign-On for Google Apps
http://www.ai-lab.it/armando/pub/fmse9-armando.pdf
199
10. Conclusion
Research Report on the Security of MFPs
10. Conclusion
The MFP is one of the products that shall be considered of the numerous vulnerabilities in the
usage in the offices where protected assets are handled. Protected assets stored on the HDD or
SSD of the MFP should have the same level of security as file servers in the offices. Moreover,
interfaces, including the websites that are provided to administrators and users, shall eliminate
the possibility of attacks, such as buffer overflow and injection, etc. In that sense, the MFP is
required to have security-conscious operations as much as the file servers and web servers in
the offices, and should be installed with the appropriate functions to ensure the security that
enables such operations.
This Research Report V2.0 explained specifically about the vulnerabilities that the MFP users,
developers and evaluators, who evaluate security functions, should be aware of. This report
covers aspects of all vulnerabilities since fiscal 2010 and later, that have been reported in the
CVE with respect to printers and MFPs. This research found out that lots of vulnerabilities
among these are discovered on the MFPs overseas, and MFPs in Japan which are used in a
security-conscious environment as an assumption have reported almost no vulnerabilities.
However, some of the attack procedures described in this report have been used to make
successful attacks against the MFPs of Japanese MFP vendors using the verification
experiments, and it is confirmed that there are some vulnerabilities in the Japanese MFPs as
well. These vulnerabilities may not be conspicuous in some forms of usage. When the users
purchase the security-conscious MFPs, it is desirable to check with developers that there are no
problems with vulnerabilities in view of the usage environment and security policies in the
offices.
Due to new additional functions and cooperation with external services in the future, it is
considered that new vulnerabilities of the MFP will be discovered, and that simple attack
methods that seem to be unrealistic at this point will be published as well. In order for MFPs as
security products representing Japan to continue to be used throughout the world, both users
and the developers should continue to check vulnerability information and take measures
respectively.
200
Research Report on the Security of MFPs V2.0
IT Security Center, Technology Headquarters, Information-technology Promotion Agency, Japan
March 2013
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