iOS Hardening Configuration Guide

iOS Hardening Configuration Guide
March 2012
iOS Hardening Configuration Guide
For iPod Touch, iPhone and iPad devices running iOS 5.1 or higher.
March 2012 (minor update)
About this Guide
This guide provides instructions and techniques for Australian government agencies to
harden the security of iOS 5 devices.
Implementing the techniques and settings found in this document can affect system
functionality, and may not be appropriate for every user or environment.
However agencies wishing to differ from the mandatory controls specified in this guide must
note that the product will no longer fall under the evaluated configuration. In these cases,
agencies should seek approval for non-compliance from their agency head and/or
accreditation authority to allow for the formal acceptance of the risks involved.
iOS Evaluation
As per the Evaluated Product List, the Defence Signals Directorate (DSD) has found Apple
iOS data protection classes A and B to be suitable for downgrading the handling of
PROTECTED information to that of Unclassified. This document provides guidance on policy
that either must be enforced or is at the agency’s discretion.
iOS and the Australian Government Information Security Manual
This guide reflects policy specified in the ISM. Not all ISM requirements can currently be
implemented on iOS 5 devices. In these cases, risk mitigation measures are provided (see
Appendix E).
Chapter Six provides recommended passcode settings for iOS devices. This advice has
been developed based on an assessment of security risks related specifically to iOS 5, and
takes precedence over the non-platform specific advice in the ISM.
About the Defence Signals Directorate
As the Commonwealth authority on the security of information, the Defence Signals
Directorate provides guidance and other assistance to Australian federal and state agencies
on matters relating to the security and integrity of information.
For more information, go to
1|Defence Signals Directorate
This guide is for users and administrators of iOS 5 or later devices. These devices
include the iPod Touch, iPhone and iPad.
To use this guide, readers should be:
familiar with basic networking concepts
an experienced Mac OS X or Windows administrator
familiar with the Mac OS X or Windows interface.
Parts of this guide refer to features that require the engagement of the technical
resources of agency telecommunications carriers, firewall vendors, or Mobile Device
Management (MDM) vendors. While every effort has been made to ensure content
involving these third party products is correct at the time of writing, agencies should
always check with these vendors when planning an implementation.
Additionally, mention of third party products is not a specific endorsement of that
vendor over another; they are mentioned as illustrative examples only.
Some instructions in this guide are complex, and if implemented incorrectly could
cause serious effects to the device, the network and the agency’s security posture.
These instructions should only be used by experienced administrators, and should
be used in conjunction with thorough testing.
Finally, for further clarification or assistance, Australian Government IT Security
Advisors can consult the Defence Signals Directorate by emailing or calling the DSD Cyber Hotline on 1300 CYBER1
(1300 292 371).
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What is in this Guide
This guide aims to assist in securing iOS 5 devices. It does not attempt to provide
comprehensive information about securing computers and servers.
This guide includes the following chapters:
Chapter One
Introduction to Mobile Device Security Architecture ____________ 7
Chapter Two
Encryption in iOS______________________________________ 17
Chapter Three Security Features and Capabilities ________________________ 23
Chapter Four
Deploying iOS Devices _________________________________ 29
Chapter Five
Suggested Policies ____________________________________ 38
Chapter Six
Recommended Device Profile Settings_____________________ 42
Chapter Seven Mobile Device Management______________________________ 52
Appendix A
Security Checklist _____________________________________ 54
Appendix B
Configuration Profiles Format ____________________________ 58
Appendix C
Sample Scripts _______________________________________ 60
Appendix D
Example Scenarios ____________________________________ 63
Appendix E
Risk Management Guide ________________________________ 65
Appendix F
Firewall Rules ________________________________________ 69
Note: Because Apple periodically releases new versions and updates to its software,
images shown in this document may vary from what appears on the screen.
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Using this Guide
The following list contains suggestions for using this guide:
Read the guide in its entirety. Subsequent sections build on information and
recommendations discussed in prior sections.
The instructions in this guide should always be tested in a non-operational
environment before deployment. This non-operational environment should
simulate, as far as possible, the environment where the device will be
This information is intended for mobile devices running iOS 5. Before
securely configuring a device, determine what functions that device needs to
perform, and apply security configurations to the device or supporting
infrastructure where applicable.
A security checklist is provided in the Appendix to track and record the
chosen settings for each security task and note which settings are changed to
secure the iOS device. This information can be helpful when developing an
agency security standard.
Important: Any deviation from this guide should be evaluated to determine security
risks and take measures to monitor or mitigate those risks.
Note: Documentation and advice is periodically updated by both DSD and relevant
vendors. DSD recommends that agencies review revised help pages and new
editions of guides.
Getting Additional Information
For security-specific information, consult the following:
Australian Government Information Security Manual —DSD provides information on
securely configuring proprietary and open source software to Australian
Government standards. Additional information for Australian government
agencies, contractors and IRAP assessors, is available from DSD’s
“OnSecure” portal
Apple iOS Security
( —
Apple have released a good high level overview of iOS Security features.
NSA security configuration recommendations
( —The
US National Security Agency (NSA) has also published a list of security
recommendations for iOS 5.
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NIST Security Configuration Checklists Repository
( — is the US National Institute of
Standards and Technology (NIST) repository for security configuration
DISA Security Technical Implementation Guide
(— is the US Defense Information Systems Agency
(DISA) guide for implementing secure government networks. A US
Department of Defense (DoD) PKI Certificate is required to access this
CIS Benchmark and Scoring Tool
Center for Internet Security benchmark and scoring tool is used to establish
CIS benchmarks.
For further information consult the following resources:
Apple Product Security website
(—access to security information and
resources, including security updates and notifications.
Developer documentation
( Registered developers get access to WWDC
session videos and PDF documents. Free registration allowing access to
documentation and developer SDK is available.
Apple Product Security Mailing Lists website
(—mailing lists for
communicating by email with other administrators about security notifications
and announcements.
iPhone, iPad and iPod Touch manuals
( —PDF versions of all product
iPhone, iPad and iPod Touch user guides
(,, — available as HTML5 web applications that
work offline on the devices
iPhone in Business website
(—reference point for all
enterprise related documentation for iOS integration.
Apple Developer Website
( registration required, contains extensive
information on enterprise deployment of iOS devices, developer
documentation on APIs and programming techniques for both web based and
native iOS applications.
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iOS Enterprise Deployment Articles
( – provides a detailed reference on a
variety of enterprise deployment themes. These can be found in the iOS
Developer Library under the “Networking & Internet” – “Enterprise
Deployment” topic.
Apple Discussions website
(—a way to share questions, knowledge, and
advice with other administrators.
Apple Mailing Lists website
( — subscribe to mailing lists so agencies can
communicate with other administrators using email.
Open Source website
(—access to Darwin open source
code, developer information and FAQs.
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Chapter One
Introduction to Mobile Device Security
Mobile devices face the same security challenges as traditional desktop computers,
but their mobility means they are also exposed to a set of risks quite different to
those of a computer in a fixed location.
This chapter provides the planning steps and architecture considerations necessary
to set up a secure environment for mobile devices. Much of the content in this
chapter is platform agnostic, but some detail is written to specific features available in
iOS 5. Not all of these options discussed will be applicable to all environments.
Agencies need to take into account their own environment and consider their
acceptable level of residual risk.
This chapter makes some basic assumptions regarding the pervasive threat
at some point, there will be no network connection present
all radiated communication from the device has the potential to be monitored
all conventional location, voice and SMS/MMS communications are on an
insecure channel 1
1 Although GSM for example is encrypted on some carrier networks, it is not encrypted on all, and some of the GSM encryption algorithms such
as A5/1 on 2G networks are vulnerable to attack with rainbow tables. With moderate resources, it is also feasible to execute a MITM attack
against GSM voice and have the MITM tell client devices to drop any GSM encryption.
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certain infrastructure supporting mobile devices can be trusted
carrier infrastructure cannot always be trusted as secure in all countries.
Device Security off the Network
Once a device is off the data network, then protection of data on the device is
determined by how the device implements data protection locally. There can be no
referral to a server for policy, or any remote wipe command, if there is no network
When off the network, the security of the device is determined by:
what policy has been cached locally from Exchange ActiveSync (EAS) or
Configuration Profiles
what the security settings set locally on the device are
the device’s cryptographic capabilities
the correct use of file protection classes and keychain by Apps
the strength of the device passcode.
Device Security on the Network
The general principle that applies for all data when the device is on a network is that
wherever possible, all network traffic should be encrypted, noting that all classified
network traffic must be encrypted as per the Cryptographic Fundamentals section of
the ISM. This is not merely achieved by turning on a Virtual Private Network (VPN)
for all traffic. Typically this involves using a mixture of:
SSL to encrypt connections to specific hosts such as mail servers or
management servers that need to be highly reachable
SSL for any traffic that has sensitive data on it
a VPN for more general intranet access
WPA2 with EAP-TLS as a minimum for Wi-Fi security
802.1X authentication on Wi-Fi networks combined with Network Access
Controls to compartmentalise Wi-Fi access to defined security domains
a custom, authenticated APN 2 in conjunction with carriers to
compartmentalise mobile data traffic to defined security domains
data at rest encryption on mobile devices and transport security.
Apple Push Notification Service
Many Apps and services associated with iOS devices take advantage of the Apple
Push Notification Service (APNS). APNS allows Apps to be sent small notifications,
such as updating the badge on an icon, playing an alert tone, or displaying a short
text message.
Examples of Apps that may use APNS include push email notification, Mobile Device
Management (MDM) servers, and iOS client/server applications that are able to
execute in the background (e.g. VoIP Apps, streaming audio Apps, or Apps that need
2 Access Point Name (APN) See the agency telecommunications carrier for more detail.
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to be location aware). MDM servers send a request to the MDM agent on the device
to “phone home” using APNS. The device and MDM server then exchange XML
queries and responses inside an SSL tunnel.
Figure 1: Apple Push Notification Service
It will be necessary to set appropriate firewall rules to enable APNS. Refer to
Appendix F for information on ports and services.
Data Roaming
Data roaming generally refers to a process by which a device from a specific carrier’s
network can take advantage of the data service on a different carrier. For example a
device with a SIM from an Australian carrier, being used in the US on a US carrier’s
network takes advantage of the carrier’s data infrastructure. Note that roaming need
not be international; in some countries carriers with different coverage areas may
allow some data roaming to avoid infrastructure duplication.
There are two main risks associated with data roaming.
When roaming internationally, there are both implied and actual lower levels
of trust with the level of eavesdropping and traffic analysis occurring on the
foreign network. As soon as traffic goes international, it is no longer subject to
the privacy and consumer protection requirements that apply to purely
domestic communications in the host country. It is incorrect to assume that
the rights protecting individual’s privacy are uniform internationally.
If data roaming is switched off for cost management, then the device is “off
the grid” for management and monitoring consoles such as EAS, MDM, or
iCloud’s “Find My iPhone”. In some cases, private APN data can be
preserved across international boundaries because of commercial
arrangements between carriers. Note that data costs can still be high.
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One of the major attractions of the iOS platform is the availability of a wide range of
Apps and ease of App development. As outlined in DSD’s Strategies to Mitigate
Targeted Cyber Intrusions, DSD recommends that only applications that are required
should be installed. There are a number of ways to procure and load applications
onto an iOS device.
App Store
The App Store is hosted and curated by Apple, and is focused on mass-market
distribution of paid and free applications. These Apps are loaded to a device either
over-the-air (OTA) from the App Store itself, or via the iTunes application on the host
computer for the iOS device.
Apple maintains discretionary control of curating App Store content, and can remove
applications for a variety of reasons. DSD recommends that Apps are tested and
approved prior to use within an agency.
Although App Store applications come from a curated environment and the runtime
environment the Apps execute in is a relatively hardened one, agencies should
assess the risks associated with allowing unrestricted user-initiated installation of
Apps. Some risks that need to be considered are:
the inappropriate use of data protection
the inappropriate use of transport security
the inappropriate access of contact list, photos and location information
registration of URL handlers.
Agencies can manage these risks through discussions with the App developer or
through conducting professional penetration testing.
Through the use of an Ad-hoc provisioning profile, up to 100 instances of a signed
application binary can be installed via iTunes, iPhone Configuration Utility or Apple
Ad-hoc applications are locked to a specific set of devices by the provisioning profile.
These are most commonly used for beta testing of applications, or where very
restricted distribution of a small number of instances of a bespoke application is
Enterprise In-House Apps
Agencies with a Dun and Bradstreet Data Universal Numbering System (DUNS) 3
number can apply to become Enterprise developers. This allows the creation and
distribution of custom applications and provisioning profiles within an agency for its
DUNS is a unique nine digit number assigned to business by Dun and Bradstreet. See for more information.
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own use, of which the distribution is limited to their employees and contractors (i.e.
not to the general public).
Enterprise In-House Apps can be installed using:
iPhone Configuration Utility
Apple Configurator
OTA via a web site
managed Apps using a MDM server.
Volume Purchase Program (VPP)
The VPP allows businesses to buy app store apps in bulk using a corporate
purchasing card. VPP is not available in Australia. For more information on VPP go
Managed Apps
App Store and Enterprise In-house Applications installations can be triggered via an
MDM server; these Apps are called “Managed Apps”. Managed Apps can be
uninstalled by the MDM server along with any associated data or can be set to
uninstall when the MDM profile is removed. Paid App Store Apps can be installed but
require VPP which is currently unavailable in Australia.
Web Apps
Safari Mobile has extensive support for HTML5, CSS3 and JavaScript features for
Web Apps, including Apps that run full screen and offline. The Product Guides for
iPod Touch, iPhone and iPad are all examples of these.
Web Apps are often a useful mechanism to deploy informational applications quickly
from a central intranet point; however Mobile Safari on iOS is still subject to the same
threats as other browsers.
GSM Voice and SMS/MMS Communication
As noted previously, GSM voice and SMS networks have a number of security
weaknesses, where the confidentiality or authenticity of a voice or SMS
communication cannot always be ensured, due to both ‘Man-in-the-Middle’ attacks
and the variation in the security features implemented by carriers. As such, voice and
SMS communication should generally be considered less secure than methods that
implement a chain of trust back into a user’s own agency such as SSL tunnelled
iMessage in iOS 5 has not currently been evaluated by DSD and should be treated in
the same way as MMS.
Since the release of iOS 5, iTunes is no longer a requirement for device
management. If agencies decide to use iTunes as part of their device management
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workflow it can be locked down for use on agency Standard Operating Environments
(SOE) via registry keys or XML property lists as detailed here:
Apple IDs
One of the organisational risks that some users express concern about is a
perceived need to associate a credit card with every Apple ID. This is actually a
misconception, and no association with a credit card is required. The following
approaches are recommended at the policy and procedural level.
For a Bring Your Own Device (BYOD) model, there is generally implied trust
that users can continue to install Apps on their own device. Therefore, users
may register their existing Apple ID as part of the process of submitting to the
agency Acceptable Use Policy (AUP). If users then purchase approved Apps,
using their own credit card, they can be reimbursed. This provides one
method to control expenditure of agency funds. An MDM console can be
used to monitor what applications have been installed.
For an agency device model, where users are not allowed to install their own
Apps, per device Apple IDs are created that are not linked to a credit card.
The process for doing this is described here:
Individual App redemption codes, or store credit can then be gifted to those
accounts and installed on the devices from an agency owned computer using
iTunes. Note: The end user requires the Apple ID password in order to enable
application updates.
Apple IDs can be optionally used to create free iCloud accounts to facilitate
user initiated device location and remote wipe.
The most restrictive approach is to not reveal the Apple ID password to the
end users, and install App Store Apps prior to issue of the device to the end
user. However, to update these devices, there is an additional support load,
as updates must be completed by IT staff. This approach is recommended for
small controlled deployments only.
Enterprise In-House Apps can be deployed either by iTunes, or OTA to
devices, using a secure web site. In all the above cases, an MDM console
allows monitoring of which App versions are installed on a device, allowing a
management decision as to when updates are required. An MDM console
can push a webclip to allow downloading of Enterprise In-House Apps to a
fleet of devices.
Siri provides voice to text services using servers around the world rather than the
device. Any dictation performed using Siri must be considered Unclassified. By
default Siri can be used from a locked screen to perform actions such as opening
emails and reading calendar entries. This behaviour can be disabled via
configuration profile while still allowing Siri when unlocked.
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Planning Questions
The following questions offer a guide for considerations in implementing policy on the
How sensitive is the data I am
intending to view or store on a mobile
In all cases a strong passcode should be
set on the device in order to enable data
protection. If the data is coming over a
network, then it should be secured by
some combination of encryption, typically
SSL or VPN. If the data is classified refer
to the ISM Controls Manual Cryptographic
Fundamentals section.
Is it appropriate that data gets to the
device over a mobile data or wireless
Using Apple Configurator on a trusted
computer may be an acceptable
alternative to transport security.
Do I want users to collaborate using
that data in a networked fashion?
If users need to share data over a
network, then a secure connection should
be in place between the users
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Does my agency want to allow
employee owned devices to access
some agency data?
Allowing employee owned devices usually
has a significant reduction in costs in both
procurement and management of mobile
device fleets, but introduces a different
set of expectations about the level of
control an agency can exert over the
devices. The balance point between
control and flexibility is usually different,
and is more consultative in process, than
for agency owned devices.
An important point to remember is that
agencies will need to consider their
legislated privacy obligations when
determining policy for accessing/wiping
employee owned devices.
Does my agency want to allow a
mixture of employee and agency
owned devices?
If mixed device ownership is allowed, then
consideration needs to be given to which,
if any, differences in access to information
and services are appropriate. In some
cases this could involve the use of
managed container applications to
separate agency data from personal data.
Does my agency need different
policies applied to a device
depending on whether it is employee
or agency owned?
This is a complex issue that requires a
mixture of user initiated opt-in
Configuration Profiles, MDM managed
profiles and pre-installed profiles on a per
device basis, appropriate to its context. In
some cases this could involve use of
managed container applications to risk
manage the separation of agency data
from personal data.
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What balance does my agency need
to set between the advantages of
users being able to install App Store
Apps themselves, versus the
overhead of managing this centrally?
The more sensitive the data being
accessed by a device is, the greater the
risks are. Typically a combination of an
approved whitelist and monitoring via
MDM will mitigate the risks. At high levels
of sensitivity, applications may need to be
pre-screened, and pre-loaded by IT staff
before device issue, or developed inhouse and deployed to devices.
Do my agency’s acceptable usage
policies require explicit education
and enforcement?
AUP compliance prior to devices being
deployed is critical. AUP education
content can be provided as a Web App
and Web Clip on the devices for user
reference. Other policy controls via EAS,
MDM and Configuration profile may be
Are all of my devices with one carrier,
and agency owned?
If agencies have a single billing
arrangement with a carrier, then use of a
custom secured APN with a proxy, can
assist in enforcing tighter policy controls
for devices on the mobile data network. In
many cases, a custom APN with EAS and
an authenticated, SSL encrypted reverse
proxy may be sufficient security for lowlevel sensitivity data.
Do I need to support devices from
multiple carriers and a mix of
personal and agency ownership?
A VPN solution may be more appropriate
than a custom APN.
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How can an agency remote wipe
devices or secure containers
whenever they are reachable on the
Remote wipe is usually best managed by
a combination of EAS or an MDM
console. If agencies do not have a 24/7
service desk capability, then use of
Outlook Web Access (OWA) or iCloud
can allow user-initiated remote wipes.
To what level does the agency care
about its data being monitored and
recorded by a third party?
Use of SSL, Wi-Fi encryption, and VPN
needs to be considered as per ISM
How does an agency develop
applications that are customised to
its environment?
In-house application development needs
to be done in either
HTML5/CSS3/Javascript, or native
applications code signed with an
Enterprise Development Certificate.
Native Apps and Web Clips to web
applications can be pushed OTA to
devices that are under the control of an
MDM server.
Does access to my agency
information need to be pervasive?
If access to agency data is primarily
appropriate on a site or campus, then
potentially, focus on Wi-Fi security and
limit agency data access, such as EAS
PIM, or limited web site access via a
reverse SSL proxy.
Do I need to be able to locate devices
Use of iCloud or an MDM can provide this
Do I need to digitally sign email (e.g.
iOS 5 supports S/MIME, it does not
natively support the use of PGP.
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Chapter Two
Encryption in iOS
This chapter is provided to help agencies understand the underlying encryption
architecture employed in iOS 5 to help make an informed assessment of the risks to
Australian government information.
Data Protection
Apple has explained that one of the goals of iOS is to 'keep data safe even when the
device is compromised'. However, as will be explained in this chapter, the onus
remains largely on the developer as to how much or how little data protection is
For this reason, it is important that an agency wishing to use a particular application
understands security features of iOS 5 in order to make a more informed decision as
to whether the application meets the security needs of the agency.
This is particularly important, as at the time of this publication, the only native
application making full use of data protection within iOS 5 is Mail. It is important for
administrators to note that users can still move attachments out of Mail to other Apps
that use lower data protection classes. This can happen if installed Apps have
registered URL handlers for file types. For PROTECTED devices, agencies should
not allow user installation of Apps.
Secrets and Data
Within iOS 5, information stored by Apps can be broadly categorised as either a
secret or as data. The term secret can be understood to mean information by which
one may get access to data; this can include system credentials, keys and
passwords. Data on the other hand, refers to user/application data such as text,
pictures, documents and alike.
Accordingly there are two data stores where a developer may choose to store
information: the File System and the Key Chain. Developers are encouraged to store
secrets within the Key Chain and place more general application data within the File
Information stored within either of these stores can be customised to different levels
of security, accessibility and portability. Note that it is entirely up to the developer to
determine the level of protection applied. This choice is made by the App developer
through API calls and the choice of availability as detailed in Table 1.
It is important to note that the default file system protection class on files is ‘None’
(accessible always), while key chain items are set to '...WhenUnlocked' (accessible
only when unlocked).
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Note: Agencies developing or making use of applications handling sensitive data
should take care to investigate how data is handled within their application. They
must ensure the appropriate data stores and availability flags (outlined in Table 1)
are used to achieve the secure handling of Australian government information.
Classes of Protection
In version 4 of iOS, Apple introduced the concept of protection classes for stored
data. This has continued in iOS 5 with some important enhancements.
An application developer has the option of setting the following availability flags with
any File System Element or Key Chain entry they create.
File System Element
Key Chain Entry
When unlocked
While locked
After first unlock
Table 1: Assignable File System and Key Chain Properties
From Table 1, it is possible to abstract these settings into four standard classes of
containers with the following behaviour:
Class A: Files and credentials within this class can only be read or written when
the device is unlocked.
Class B: Through the use of public key cryptography, files within this class can be
written after the device is initially unlocked, and can be read only when unlocked.
Class C: Files and credentials within this class can be read or written only after
the device is initially unlocked.
Class D: The lowest protection class, files and credentials within this class can be
read or written to in all conditions.
iOS 5 Encryption Architecture
Figure 2 illustrates an example where four files exist, each assigned a different class:
File 1 is of type Class A: accessible only when unlocked.
File 2 is of type Class B: can be written to after first unlock, but can only be read
when unlocked.
File 3 is of type Class C: accessible after first unlock.
File 4 is of type Class D: accessible always.
Note that while files were used for the purposes of this example, with the exception
of Class B, Key Chain entries could just as easily be used in their place.
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Similar to the File System, an application's credentials stored within the Key Chain
are encrypted using the appropriate Class Key found within the System Keybag
(please see the Keybag Section for more information).
However, as illustrated in Table 1, the protection offered by Class B is only available
to File System Elements.
Figure 2: File System Architecture
As can be seen in Figure 2, irrespective of class, each file is encrypted with both a
unique File Key and a File System Key.
The File System Key is used to encrypt all data within the device. As it is stored
openly its use does not add to the cryptographic security of data, but is instead used
to facilitate a remote wipe. Please see the Remote Wipe section for more information
regarding this function.
The File Key is stored within the file’s metadata, which is itself encrypted by the file’s
corresponding Class Key. The System Keybag stores all Class Keys within the
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device. Please refer to the Keybag section for more information on different types of
Keybags used throughout the system.
Upon turning on the device, the Class A, Class B (public and private) and Class C
keys are initially inaccessible as they rely on the Passcode Key to be unencrypted.
When the device is first unlocked by the user, through the use of their Passcode,
these keys are unencrypted, stored for use and the derived Passcode Key promptly
The Device Key is stored within, and never divulged from, the Hardware Security
Module (HSM). This acts to encrypt and decrypt files at will using the Device Key.
Please refer to the Hardware Security Module Section for more information on this
As can be observed, the Class D Key is encrypted using the Device Key. As this
decryption process is always available, irrespective of the state of the device, files
protected by this Class Key are accessible always.
Finally, when the device re-enters a locked state, the Class A Key and Class B
Private Key are forgotten, protecting that data, leaving the Class C Key and Class B
Public Key accessible.
Remote Wipe
Remote Wipe is the ability for a network connected iOS device to have the data
within the device made inaccessible (enacted by received system command). This is
achieved in iOS by erasing the File System Key, which is used by the device to
encrypt all user data (as shown in Figure 2). For this reason, once this key is
removed, no user data within the device is retrievable.
Hardware Security Module (HSM)
Internal to the device, the HSM is the only means by which iOS can make use of the
Device Key. This Device Key is unique to the device and is not exportable using any
non-invasive technique.
For this reason (as files encrypted with the Device Key can only be decrypted on the
device), the iOS architecture makes itself resistant to off-line attacks. The most
significant being a brute-force to exhaust and thus discover the user's Passcode Key.
There are three types of Keybags used in iOS: System, Backup and Escrow.
All Keybags are responsible for storing the systems Class Keys, which are in turn
used to gain access to individual files or Key Chain entries (as shown in Figure 2).
The System Keybag, shown in Figure 2, is used internally within the device to
facilitate the user’s access to the File System and Key Chain.
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The Backup Keybag is designed to facilitate backups in a secure manner. This is
done by transferring the encrypted contents of the File System, and Key Chain to a
remote system along with the Backup Keybag.
The user then has the option to password protect this Keybag; this decision has
implications concerning the portability of the Keybag. If the user specifies a
password, the Backup Keybag is then encrypted with this password.
Given the password, this data can then be restored to an iOS device (note however
that if a developer has specified data 'ThisDeviceOnly', such data will not be made
portable). If, however, the user does not set a password, then the Backup Keybag is
protected using the Device Key which never leaves the device. Consequently, the
Backup Keybag can only be restored to the original device.
The Escrow Keybag is designed to enable a paired device (normally a computer) to
gain full access to the device's file system when the device is in a locked state.
Pairing in this context refers to connecting the iOS device in an unlocked state (or
within 10 seconds of being in an unlocked state) to the other device in question.
An exchange then occurs, where the paired device receives a copy of the iOS
device’s Escrow Keybag. This Keybag is encrypted using the iOS device's Device
Key, thus restricting access when disconnected from the iOS device.
Questions to ask App Developers
1. What is the flow of data throughout the application; source, storage,
processing and transmission?
2. Of the data stored on the device, what class of container is it stored in?
Note: Application data should always use Class A for storage where
possible. If the application needs the ability to write to data in the
background, Class B should be considered.
3. Of the data transmitted or received, is it done through a secure means?
Agencies can refer developers to the Apple WWDC 2011 presentation,
Session 208 on Securing iOS Applications.
4. What system or user credentials are being stored? Are they stored using
the Key Chain Class A? If not why not?
References and Further Reading
For more information on the encryption used in iOS, please refer to the following:
"iPhone data protection in depth" by Jean-Baptiste Bedrune and Jean
Sigwald from SOGETI
"Apple iOS 4 Security Evaluation" by Dino A. Dai Zovi
"Session 208 Securing iOS Applications", Apple Developer WWDC 2011
21 | D e f e n c e S i g n a l s D i r e c t o r a t e
Additionally Sessions 204 and 209 from the Developer WWDC 2010 Presentation
provide relevant background information on iOS 4.
Verifying Data Protection is Enabled
There are two main methods of verifying that the file system of a device has been
configured to support data protection. An MDM console can query the data protection
status and report centrally. The user of a device can also validate if data protection is
enabled by navigating to Settings Æ General Æ Passcode Lock and scrolling to the
bottom of the screen. If data protection is enabled, “Data protection is enabled” will
be displayed at the bottom of the screen.
Figure 3: iOS device with data protection enabled
Setting a Passcode
The last step in activating data protection is to set a passcode. In most environments
enabling a passcode will form part of agency policy, and this will be enforced either
over EAS, or via a configuration profile installed on the device. For password policies
see chapter six.
22 | D e f e n c e S i g n a l s D i r e c t o r a t e
Chapter Three
Security Features and Capabilities
This chapter covers mobile device security features, and the enabling technologies
for implementing those features under iOS and related infrastructure.
Mobile Device Security Toolbox
When setting up a secure system that uses mobile devices, the security tools and
solutions are not on a linear scale, where a solution to a higher security environment
is provided by one product alone. Rather, the security posture of the devices can be
progressively improved by combinations of capabilities shown below.
Figure 4: Security Features and Capabilities
23 | D e f e n c e S i g n a l s D i r e c t o r a t e
Security features in iOS
iOS provides a number of features that include:
management of credentials and passwords with Key Chain
encryption of data in transit (using DACA 4 and DACP 5 )
encryption of data at rest and in transit (using DACA and DACP)
digital signatures, certificates and trust services
randomisation services
code signed applications.
Enterprise In-House Applications developed for an agency should generally take
advantage of these services, rather than re-inventing the same capabilities. More
information is available in detail from the Apple Developer web site:
Figure 5: Security Services in iOS
iOS 4.2.1 introduced no-cost “Find My iPhone” functionality for iOS devices using a
MobileMe account. In iOS 5 this same functionality is accessible with an iCloud
account. The link below contains user level information on how to use the service.
Typically this would only be for employee owned devices.
DSD Approved Cryptographic Algorithm
DSD Approved Cryptographic Protocol
24 | D e f e n c e S i g n a l s D i r e c t o r a t e
Find My iPhone user interface
Generally, when agency devices are used, the iCloud account would be the same as
the Apple ID used to install agency owned Apps, and set up prior to issuing the
device. Note that this requires a network connection, location services to be active,
and the device to have opted in to the “Find My iPhone” service.
Agencies may opt to present some agency applications to iOS devices over a
network via a Virtual Desktop Infrastructure (VDI).
This works particularly well for users who are “micromobile” i.e. they move about a
building or a campus during their work day, and able to take advantage of the
relatively high bandwidth of a secure Wi-Fi network, but are not strictly away from the
office location. Solutions in this space provide an ability to tune the application UI for
a small screen suitable for presenting to mobile devices, rather than merely
presenting a remote session to the standard agency desktop resolution. Due to
dependency on network performance and differences in screen sizes and input
device sizes, VDI based solutions should be thoroughly tested from a usability
perspective. This approach also has the advantage that minimal agency data is
stored on the device.
Note: Most major authentication token vendors have a soft token available for iOS.
Note: In some cases use of VDI is a classic usability/productivity trade off against
security, as the absence of locally cached data means users are not able to be
productive when the device is off the network and there is no integration with
native applications running locally on the end point device.
Sandboxing ensures that applications that run on iOS devices are restricted in terms
of the resources that they can access. This is enforced by the kernel. For detailed
information on the iOS/OS X sandbox see Dion Blazikis’s paper “The Apple
Sandbox” 6 or Vincenzo Iozzo’s presentation “A Sandbox Odyssey” 7 .
25 | D e f e n c e S i g n a l s D i r e c t o r a t e
Managed Container Applications
For employee owned devices, or in cases where the agency requires greater
protection of their contact and calendar information a third party solution may be
required. A number of solutions can be used to provide additional levels of
separation and policy enforcement for email, calendar and contact data managed by
dedicated servers.
There is usually a usability/security trade off in the configuration, with custom
solutions having a lower level of integration with other Apps on the device (e.g. it may
not be possible to take a photo with the device’s camera, and then send via email
using the third party email client).
Note: Currently no third party managed container applications have been evaluated
by DSD.
Content Filtering
Access to intranet sites and some mail, contact or calendar data can be achieved via
reverse proxies and content filters. There are multiple solutions in this space.
EAS filtering products can be used to ensure email sent to Exchange ActiveSync
devices have appropriate privacy markings for the classification the device is
approved to by an agency. This approach can allow for an asymmetric strategy mobile devices only receive email content at a classification appropriate to the
device, as well as having policy and controls applied to the email content.
In this scenario, the agency’s Wide Area Network (WAN) security domain is not
extended out to the mobile device, and there is no need to lower the classification of
the agency WAN. Such solutions can be used to redact specific content patterns
from emails sent via EAS, for example, to scrub credit card numbers from all emails
synced to mobile devices. This class of tools can also facilitate correct protective
marking of email coming from mobile devices without direct on-device support for
Australian government marking standards. For further information see the ISM
section on Content Filtering.
26 | D e f e n c e S i g n a l s D i r e c t o r a t e
Remote Wipe
MDM, EAS, Apple Push
Notification Service
(APNS), Find My iPhone
Custom APN, VPN
iOS 5 does not implement a
global proxy setting. A proxy
can be set on a custom APN
and a VPN session.
Firewall on custom APN,
Firewall on Wireless
iOS 5 does not implement a
local firewall. This is
significantly mitigated by the
runtime environment.
Force Device Settings
iPCU, Apple Configurator
and MDM
Enterprise Deployment
Guide lists an XML schema,
this can be used to generate
and sign profiles from
custom scripts. iPCU is an
easy to use GUI tool to
generate the XML, but CA
integration requires signing
with OpenSSL tools.
SSL CA infrastructure,
DNS, RSA or CryptoCard
(VPN Only), Smartcard
(Requires third party
Depending on the agency’s
security posture, device
certificates or soft tokens
may be considered as a
second factor of
OTA Configuration
Profile (pull)
SSL CA infrastructure,
DNS, Web Service,
Directory Service
Externally sign and encrypt
profiles, do not sign with
27 | D e f e n c e S i g n a l s D i r e c t o r a t e
OTA Configuration and
Provisioning Profiles
Enterprise Developer
Agreement, 3rd Party
MDM appliance, Apple
Configurator, SSL CA
infrastructure, DNS,
Directory Services, APNS
MDM should be tied into CA
and Directory Services.
Mobile Device
Enterprise Developer
Agreement, 3rd Party
MDM appliance, CA
infrastructure, DNS,
Directory Services, APNS
MDM should be tied into CA
and Directory Services.
Mobile Device
Enterprise Developer
Agreement, 3rd Party
MDM appliance, CA
infrastructure, DNS,
Directory Services, APNS
MDM should be tied into CA
and Directory Services.
Remote Application
Enterprise Developer
Agreement, Web Server,
3rd Party MDM appliance
(optional), APNS (optional)
Only Enterprise In-House
Apps can be deployed OTA.
Home screen
Set Home screen to “If
found return to PO BOX
XXXX”. This could also be
done with a Picture Frame
28 | D e f e n c e S i g n a l s D i r e c t o r a t e
Chapter Four
Deploying iOS Devices
There are a number of options open to administrators when deploying iOS devices.
iOS has a number of features that are aimed at helping administrators deploy iOS
devices in agencies. Apple distributes two important tools to help administrators
manage enterprise deployment: iPhone Configuration Utility (iPCU) and Apple
Configurator. These tools each have important specialised uses and it is important
for administrators to understand their function when planning an enterprise
iPCU + iTunes
Apple Configurator
Profile creation
Mac / Windows
Mac only
Can create configuration profiles
Install profiles
One device at a time
One device at a time
Can create configuration
Many devices at a time
Many devices at a time
Name device
Update iOS
Install Apps
One device at a time
One device at a time
One device at a time
One device at a time
Many devices at a time
Many devices at a time
Many devices at a time
Many devices at a time
Table 2: Deployment Options
There are also many circumstances that require administrators to sanitise devices for
deployment or when returning an employee owned device.
This chapter provides an overview of the tools used to manage iOS deployments and
advice on device sanitisation procedures.
Configuration Profiles
Both iPCU and Apple Configurator use configuration profiles for iOS deployment.
Configuration profiles are XML formatted plist files that contain device settings,
security policies and restrictions. An administrator may use a configuration profile to:
set passcode policy on a device
set restrictions (such as disabling use of YouTube or Siri)
configure wireless networks
configure VPN
configure email
install X.509 certificates
set a Mobile Device Management (MDM) server
29 | D e f e n c e S i g n a l s D i r e c t o r a t e
These are only a few examples of possible configuration options; please see the iOS
Configuration Profile Reference
/iPhoneConfigurationProfileRef.pdf) for more information.
Note: Configuration profiles are not encrypted. Credentials that are stored in
configuration profiles are available to anyone who has access to the files. Passwords
may be in clear text or base64 encoded. Some of the credentials that could be in a
configuration profile include:
Wi-Fi passwords
VPN Shared secrets
email usernames/passwords
ActiveSync usernames/passwords
LDAP usernames/passwords
CalDAV usernames/passwords
CardDav usernames/password
Subscribed Calendars usernames/passwords
SCEP pre-shared secrets.
Care must be taken to make sure that these files are stored appropriately and not
improperly accessed.
Provisioning Profiles
Provisioning profiles allow custom applications to be run on iOS devices. They are
often used in the following ways:
to allow developers to test applications on their devices
to allow organisations to distribute applications directly to their employees.
To obtain an enterprise distribution provisioning profile, an agency must join the
Apple Developer Enterprise Program. More information about the iOS Developer
Enterprise Program can be found at:
If the enterprise program login is compromised an adversary could install malicious
applications on users’ iOS devices.
iPhone Configuration Utility
iPhone Configuration Utility (iPCU) allows administrators to create and install
configuration profiles, install provisioning profiles and examine device information.
While iPCU can be used to install configuration profiles on devices, it may only do so
on one device at a time. If administrators are planning a small deployment, they may
find it simpler to deploy devices one at a time using iPCU.
30 | D e f e n c e S i g n a l s D i r e c t o r a t e
Installing iOS prior to deployment
iPCU cannot install iOS on devices. There are three ways to install iOS on devices:
using iTunes
using iOS 5 OTA update
using Xcode Organizer.
Activating devices
In a small deployment using iPCU, devices must first be manually activated. If an
Internet connection is available to the device, then activation can take place on the
device itself. For iPhones or iPads with a mobile data connection, activation can take
place using the device’s mobile carrier. For iPod and Wi-Fi only iPad, an internet
connected wireless network must be available to perform activation from the device.
If no internet connection is available to the device, activation must be performed by
connecting the iOS device to an internet connected host running iTunes.
If changes must be made to firewall rules, refer to Appendix F for information
concerning hostnames and ports of activation servers.
Installing Configuration and Provisioning Profiles
After an unlocked iOS device has been connected to a host computer running iPCU,
it is possible to both install and inspect profiles on a device. Configuration profiles
that were created using iPCU will be signed by iPhone Configuration Utility.
In the same way, provisioning profiles can be both viewed and installed using iPCU.
iOS Updates
Device users may perform an iOS update by either accepting an OTA update from
Apple, or by performing an update using iTunes.
For an update to be delivered via a corporate Wi-Fi network, it may be necessary to
adjust firewall rules. Please refer to Appendix F for details.
References and Further Reading
Please refer to the following publication for additional information on iPCU:
Apple Configurator
Apple Configurator allows administrators to set up and deploy groups of similarly
configured iOS devices. Administrators may use Apple Configurator to:
activate and name groups of new devices
update iOS on groups of devices
install Apps and Configuration Profiles on groups of devices
31 | D e f e n c e S i g n a l s D i r e c t o r a t e
backup/restore devices
retrieve documents
It is suggested that administrators use Apple Configurator with an MDM for large
deployments of iOS devices.
A key feature of Apple Configurator is the ability to place devices into what is called
“Supervised” mode, which changes the way devices are able to pair with hosts. A
user with a Supervised device will not be able to pair their iOS device with iTunes on
their PC. Some of the effects on users will include:
being unable to sync music or media from their computer running iTunes to
their iOS device
being unable to install Apps on their device using iTunes
being unable to backup their device using iTunes
increased difficulty in jailbreaking their device
not being notified when changes are made to their devices’ configuration
finding their administrator has placed a message on their device locked
Though it may not be appropriate to use Supervised mode in a BYOD model, there
are reasons why Supervised mode is desirable for agency owned devices.
Sensitive data on each device is better protected. Users cannot sync or
backup their device contents to their home computer. iOS forensic recovery
utilities may not be able to recover data from the device without a jailbreak.
Users cannot easily sidestep restrictions. The only viable way to bypass
restrictions is to erase the device.
Devices not configured as Supervised Devices are referred to as Unsupervised
Note: PROTECTED devices must use Supervised mode.
Supervisory Host Identity Certificate
Normally, an unlocked iOS device is able to pair with any host running iTunes (or
supporting the lockdown protocol). When an iOS device is set to Supervised mode,
it authenticates with a host using the “Supervisory Host Identity Certificate”. The
supervised device will then only pair with a host running Apple Configurator with the
correct Supervisory Host Identity Certificate. Ordinary pairing with iTunes is not
possible with any other hosts. On a Mac host running Apple Configurator, the
Supervisory Host Identity Certificate is stored in the login keychain.
While supervised devices are unable to establish new trust relationships with iTunes
hosts, a trust relationship will be formed between devices and the Apple Configurator
host. A record of this trust relationship is stored in Escrow Keybag files, which on
Mac OS X are located at /var/db/lockdown.
32 | D e f e n c e S i g n a l s D i r e c t o r a t e
Note: Escrow Keybag files in this directory should be protected in a similar
manner to private keys.
Installing iOS
A key feature of Apple Configurator is its ability to install iOS on many devices
concurrently. Additionally, varied device platforms (iPhone, iPad, iPod) can all be
simultaneously connected. Apple Configurator will seamlessly download iOS for all
supported device platforms when there is an internet connection available. A
maximum of 30 devices can be connected concurrently for installation.
Activating devices
Apple Configurator will attempt to automatically activate all connected devices after
operating system installation. It is important for administrators to note that iPhones
and iPads require a SIM for activation. If the SIM has a passcode lock, automatic
activation will be unsuccessful.
Installing Configuration Profiles
Apple Configurator may be used both to install configuration profiles and to create
new configuration profiles. These profiles can be installed on devices in bulk when
initially preparing devices for deployment. As an example, this may be used to
initially roll out a trust profile for an agency MDM server.
Figure 6: Configuration Profiles Settings
iOS Updates
There are two methods for Apple Configurator deployed devices to receive iOS
updates. Devices with an internet connection will prompt users to install OTA
33 | D e f e n c e S i g n a l s D i r e c t o r a t e
updates. Alternatively, users can return their devices to have them updated using
Apple Configurator.
References and Further Reading
Please refer to the following publication for additional information on Apple
Apple Configurator User Guide:
Device Sanitisation
Administrators should clean and re-provision devices for the following reasons:
to sanitise a returned iOS device for re-issue
to sanitise an employee owned iOS device before provisioning
to sanitise a deployed employee-owned iOS device prior to the employee
to break all device-to-host trust relationships and invalidate old Escrow
Keybag files.
Breaking the device-to-host trust relationship
When an iOS device pairs with a host, a trust relationship is formed. In many cases
an administrator may want to erase an iOS device and break all the established host
trust relationships that a device has previously created. The most reliable method to
break all established relationships is to restore the iOS device firmware using what is
commonly known as “Device Firmware Upgrade” mode (DFU mode).
Please note that restoring a device in this way will also erase all data and settings on
the device. The DFU mode restoration can be performed from a host that has no
established trust relationship with the device, and the device passcode is not
DFU Mode Restoration
To perform an iOS firmware restoration follow this procedure:
1. Connect the iOS device to the host PC running iTunes
2. If iTunes is unable to pair with the iOS device, please clear any error dialog
3. Press and hold both the Sleep/Wake and Home buttons on the iOS device for
ten seconds
4. Release the Sleep/Wake button, and continue to hold the home button
5. Release the home button after iTunes generates the following dialog box:
34 | D e f e n c e S i g n a l s D i r e c t o r a t e
6. After clicking OK, click the “Restore” button to begin installing iOS.
Sanitising an iOS device for re-issue
If an agency-owned device is returned for re-issue to another employee, it should be
cleaned by performing a DFU mode restoration. One reason that this is important is
so that the previous iOS device owner cannot take advantage of any old device-host
trust relationships to retrieve data from the device. By performing the DFU mode
restoration the old trust relationships are broken.
Before an iOS device is re-provisioned for enterprise use, it is recommended to
perform a DFU mode restoration. This will ensure that the device is in a known state.
Sanitising employee owned iOS devices
Employee owned iOS devices are making their way into government agencies,
creating a new set of challenges for administrators. Some of the challenges being
faced include:
jailbroken devices running untrusted code
jailbroken devices being able to bypass all security protection (including 3rd
party managed containers)
unpatched iOS devices that are vulnerable to exploitation
devices previously configured with conflicting settings and/or configuration
Older versions of iOS
Each revision of iOS includes many security related fixes. If left unpatched, iOS
devices could be exploited remotely, risking both employee’s personal information
and the security of the corporate network.
The agency acceptable use policy should require users to install iOS updates as they
become available.
Jailbroken employee owned devices
Jailbroken devices allow users to install applications on their iOS devices from
outside of Apple’s App Store. Jailbreaking carries with it a number of negative side
effects that impact the security of the corporate network and the confidentiality of
data stored on a device.
Jailbreaking disables application code signing checks. The iOS code signing
check helps to prevent malware executing on a device. Removing this check
makes exploitation easier and more likely.
Jailbreaking may disable or break important security features such as
Address Space Layout Randomisation (ASLR) and application sandboxing.
ASLR increases the difficulty of successful exploitation of vulnerability.
Malware on a Jailbroken device would not be constrained by the application
35 | D e f e n c e S i g n a l s D i r e c t o r a t e
Jailbreaking relies upon serious unpatched operating system vulnerabilities.
Jailbroken devices should be assumed to be untrusted.
Administrators should not allow employee owned jailbroken iOS devices to be
provisioned on the corporate network.
For these reasons it is important to ensure that devices are sanitised prior to
Sanitisation prior to deployment
When considering how to sanitise employee-owned iOS devices for enterprise
deployment, it is important to take into account the data that employees already have
on their devices. Employees may have expectations about how they will be able to
use their devices and the effect of enterprise deployment on their device. As an
example, an employee might expect their iPhone’s contact list to be preserved after
deployment. If the device is erased using DFU mode this will not be the case.
If an employee’s personal data is to be preserved, the following procedure may be
performed prior to enterprise deployment:
Take a backup of device
Perform DFU mode restore
Restore a backup to device
Delete backup from host
Provision and deploy the device as per MDM instructions
This will clear the existing host trust relationships on the device, but will preserve the
employee’s data. When following this procedure agencies must consider their legal
responsibilities to protect the privacy of their users’ data.
If there is no need to preserve an employee’s personal data on a device, agencies
should simply perform a DFU mode restore.
Sanitisation for departing Employees
When an employee departs an agency or no longer requires iOS device connection
to the agency network, it is important to remove existing host trust relationships from
the employee’s iOS device. On return, agency owned devices should be sanitised by
performing a DFU mode restore as described previously. Employees should be
made aware that agency-owned devices will be sanitised upon return.
In a BYOD model, the following procedure is suggested for departing employees:
1. Remove MDM profile from iOS device, which will:
• remove the corporate mail account installed by the MDM
• remove any Apps which have been installed by the MDM which will
also remove any associated data
2. Take backup of device
3. Perform DFU mode restore
4. Restore backup to device
36 | D e f e n c e S i g n a l s D i r e c t o r a t e
5. Erase backup files from host
This will remove any trust relationships established between the iOS device and any
agency computers. If the employee does not return their iOS device prior to
departing, it may be necessary to use the MDM remote wipe function. Employees
should be made aware of this fact in an agency acceptable use policy.
37 | D e f e n c e S i g n a l s D i r e c t o r a t e
Chapter Five
Suggested Policies
This chapter lists suggested policies in graduated levels of response, applied to iOS
devices at varying security classifications. The agency’s Information Technology
Security Advisor should be consulted for the specific usage scenarios for a
If iOS devices are being considered for use at classifications above PROTECTED,
agencies must undertake a risk assessment following the guidance in the ISM as
well as their own agency security policies and determine mitigation procedures and
policy. Agencies must also obtain appropriate approval for any non-compliance in
accordance with the ISM.
(DLM 8 )
Hardware Crypto
iOS Devices
Agency’s decision
BYOD (Bring
Your Own Device)
Agency’s decision
May be possible
(MDM opt-in for
AUP agreement
and enforcement
See ISM section on
Mobile Devices
May be possible
(MDM opt-in for
AUP agreement
and enforcement
See ISM section on
Mobile Devices
iTunes Account
Personal or
Personal or
Personal or Agency
DLM: Dissemination Limiting Marker
38 | D e f e n c e S i g n a l s D i r e c t o r a t e
(DLM 8 )
Sync to
Content/Sync to
iTunes Account.
Yes, if Personal
Generally no
Generally no
Stated in agency
usage policy
Stated in agency
usage policy
Stated in agency
usage policy
Agencies need to
assess the risk in
their own situation.
Agencies need to
assess the risk in
their own situation.
No syncing
documents and
data, No Backup.
iTunes Purchases
and iTunes Match
at Agency
User ability to
Agencies need to
assess the risk in
their own situation.
Agency approved
applications only.
agency Apple Id.
Consider MDM
enforced Agency
Store Apps
Agency approved
applications only.
agency Apple Id.
MDM enforced
Agency Store Apps
Recommended if
Exchange or Lotus
is used for agency
Recommended if
Exchange or Lotus
is used for agency
email. Second
factor of
using a certificate
is preferred.
Possible, with
authentication. For
some agencies a
dedicated mail
container or VDI for
email access may
be preferable.
Home Computer
39 | D e f e n c e S i g n a l s D i r e c t o r a t e
(DLM 8 )
EAS Filtering
Should be used if
mobile device
security domain is
lower classification
than intranet
security domain.
Should be used if
mobile device
security domain is
lower classification
than intranet
security domain.
Should be used if
mobile device
security domain is
lower classification
than intranet
security domain.
Email secured
independently of
device passcode
Use a dedicated
third party mail
Use a dedicated
third party mail
Use a dedicated
third party mail
depending on role
of device/scale of
Optional depending
on role of device or
scale of
Recommended if
BYOD model used.
Custom APN for
3G data
depending on role
SSL Reverse
depending on role
Optional depending
on role of device/
scale of
40 | D e f e n c e S i g n a l s D i r e c t o r a t e
(DLM 8 )
CA Infrastructure
depending on role
41 | D e f e n c e S i g n a l s D i r e c t o r a t e
Chapter Six
Recommended Device Profile Settings
This chapter lists the profile settings that should typically be used when an iOS
device is used on an Australian government network.
Note: If profiles are not being pushed by an MDM solution, the correct technique with
Configuration Profiles is bundling the payloads in a way that:
Profiles pulled to the device, bundle restrictions with authentication, so if the
profile is removed, all access to agency resources is removed.
If an MDM is used, the MDM master profile is always removable, but if it is
removed all managed profiles are lost as well.
Pre-loaded Configuration Profiles and MDM managed profiles can be mixed on
devices, but the MDM server cannot remove the profiles manually installed on the
The following settings are a baseline for use on PROTECTED networks. Agency
discretion can be varied to be more restrictive if required by local requirements, or
lowered at lower classifications in accordance with ISM policy. Where a profile
setting is not discussed below, agencies should examine their own particular
technical and policy needs. iPhone Configuration Utility and Apple Configurator can
be used to view the full range of profile setting that can be deployed.
42 | D e f e n c e S i g n a l s D i r e c t o r a t e
General (non-Managed Profiles only):
Figure 7: General Settings
Profile Security should be “Remove Always” if setting is for convenience for
users that does not contain any sensitive data (e.g. a subscribed calendar of
Australian public holidays). Opt-In MDM profiles would usually fit into this
category as well.
Profile security would usually be “Remove with Passcode” for profiles that IT
staff can remove temporarily. Generally users would not receive the
passcode to such profiles.
Most profiles that are not MDM managed would be set to “Never”. The
Passcode policy profile, if used, should be set to “Never”.
43 | D e f e n c e S i g n a l s D i r e c t o r a t e
Passcode (can be set via EAS depending on version, OR Configuration
Figure 8: Passcode Payload
a maximum passcode length of 90 days
do not allow simple value
require alphanumeric passcode
minimum of eight characters
auto-lock of five minutes (Note: Current maximum allowed time on iOS)
history of eight passwords
immediate device lock
auto-wipe on five failed attempts.
Depending on the EAS version, only some of the above may be set by the EAS
Server and a configuration profile would be required.
44 | D e f e n c e S i g n a l s D i r e c t o r a t e
Figure 9: Restrictions Payload
allow use of Camera: up to agency
allow use of FaceTime: up to agency
allow screen capture: up to agency
allow voice dialling: on
allow Siri (Siri utilises servers in various locations and all uses of Siri dictation
must be treated as Unclassified.)
allow Siri while device is locked: off
require iTunes Store password for all purchases
allow multiplayer gaming: up to agency
allow adding Game Center friends: up to agency
allow installing Apps: Recommend off at PROTECTED. Potentially on as an
exception at lower levels, as per discussion and mitigation measure noted
allow in-App purchase: off if App installation off, potentially on if user-installed
Apps allowed
allow automatic sync while roaming: usually off
force encrypted backups
allow Location Services
do not allow users to accept untrusted TLS certificates.
45 | D e f e n c e S i g n a l s D i r e c t o r a t e
Figure 10: Restrictions Payload
allow use of YouTube: as per agency policy
allow use of iTunes Music Store: as per agency policy
allow use of Safari: enable autofill, force fraud warning, enable JavaScript,
block popups.
46 | D e f e n c e S i g n a l s D i r e c t o r a t e
Figure 11: Restrictions Payload
allow use of explicit music and podcasts: usually off, as per agency policy
ratings Region: Australia
allowed content ratings: up to agency policy.
47 | D e f e n c e S i g n a l s D i r e c t o r a t e
Figure 12: Wi-Fi Payload
SSID of network as appropriate
hidden SSID as per agency policy
WPA2 Authentication with EAP-TLS and a pre-shared key as a minimum, but
per user RADIUS or 802.1X is recommended
protocols, authentication and trust to match network requirements. 802.1X
with device identity certificate and username/password is the preferred
authentication mechanism for Unclassified (DLM) and higher.
48 | D e f e n c e S i g n a l s D i r e c t o r a t e
Figure 13: VPN Payload
IPSec and SSL are DSD Approved Cryptographic Protocols, please refer to
the Evaluated Products List (EPL) for more information –
“VPN Server Configuration for iOS Devices” on should be consulted for server side
settings that iOS supports.
certificate based Machine Authentication. Full trust chain needs to be
split tunnel VPN should be off (set VPN concentrator side)
VPN on Demand should be enabled with a whitelist of agency URLs or
domains that device is allowed to access
proxy should be configured, ideally a PAC file.
49 | D e f e n c e S i g n a l s D i r e c t o r a t e
• Not typically needed if EAS (e.g. Exchange ActiveSync Gateway, Lotus Notes
Traveller) is in use. Otherwise appropriate to IMAP server, and can co-exist
with Exchange.
• If set, SSL only, with authentication.
Exchange ActiveSync
• Settings as per EAS server details, SSL authentication credentials required to
control both which device and which users have access to EAS.
• Note if a profile with an EAS payload is removed, all EAS synced email and
attachments are deleted from the device.
• As per agency requirements if desired. Not typically needed if Exchange GAL
is used, but can co-exist.
• SSL recommended.
• As per agency requirements if required. May not be needed if Exchange
used, but can co-exist.
• SSL recommended.
• As per agency requirements if required. May not be needed if Exchange is
used, but can co-exist.
• SSL recommended.
Subscribed Calendars
• As per agency requirements.
• SSL should be used if there is any sensitivity to the calendar data.
Web Clips
• As per agency requirements. These are “aliases” or links to URLs with a
custom icon on the home screen.
• Typical use would include links to pages for AUP, helpdesk contact details,
telephone URLs, and SCEP re-enrolment pages. Note that these web pages
could use preference manifest settings in their HTML to work when the site is
offline or the device is off the network.
• Web clips can also be used to install Enterprise In-House Applications.
• Include SSL chain of trust back to the root CA certificate, including
• Used when pre-configuring SCEP enrolment prior to device issue - rather
than OTA opt-in. OTA opt-in is the normal method used.
• Used when pre-configuring MDM enrolment prior to device issue - rather than
OTA opt-in. OTA opt-in is the normal method used.
• Usually, credentials should be added, all messages signed, and all access
rights enabled for remote administrators.
50 | D e f e n c e S i g n a l s D i r e c t o r a t e
The Development APNS should generally not be used for production
Advanced (Used when a custom APN for Mobile data is used)
• Authentication should be set.
• Proxy should be set appropriately.
All details here are worked out with the telecommunications carrier.
Other Settings not managed by Configuration Profile:
GSM Voice and SMS/MMS
• GSM Voice and SMS/MMS should only be used for Unclassified data at this
• Whilst a secure VOIP solution is technically possible, no Sectera compatible
solutions are available on iOS at time of writing.
Mobile Data
• A SIM PIN should be set prior to issue.
• Data Roaming should generally be set to off.
• Generally, Bluetooth should be set to off, unless there is a specific business
reason for its use (e.g. Bluetooth headset with a phone, or Bluetooth
Keyboard). See ISM section Mobile Devices for further information.
Picture Frame (iPad Only)
• This feature is a similar to a screen saver on the login screen.
• It should either be set to point to a specific Photo Album that contains data of
no sensitivity (under Settings Æ Picture Frame), or Picture Frame can be
turned off in Settings Æ General Æ Passcode.
• “Ask to join networks” should be set to off. This requires the user to explicitly
choose to join a network. iOS auto-joins previously known networks only.
Dock Connector
Whilst unlocked, iOS could establish a trust relationship through the dock connector
with devices or host computers. This behaviour can be managed in Supervised
devices provisioned using Apple Configurator. It is recommended that users be
instructed to only connect their iOS device to their agency-issued charger or
51 | D e f e n c e S i g n a l s D i r e c t o r a t e
Chapter Seven
Mobile Device Management
iOS 5 devices can use web and SCEP servers to establish trust relationships, and
pull policy to devices. Devices establish initial trust via SCEP and then can be
monitored and managed by servers, services or appliances using Apple’s MDM
Protocol, and APNS.
Management without MDM
Policy on iOS devices and information security can be managed by a combination of:
Configuration Profiles loaded on a device
Exchange ActiveSync policy
Network security features (e.g. SCEP, 802.1X, firewalls, Proxies, custom
APNs )
Application specific behaviour (Configuration Profiles can be loaded via the
iPhone Configuration Utility over USB, pulled OTA from a web site, or
included in piggybacked on an SCEP enrolment transaction). In addition, they
can be emailed to a device, but this can present a “chicken-and-egg”
problem. Sending an SMS containing a website URL is possible, but as SMS
can be easily spoofed, it is generally not recommended. For small scale or
limited scope deployments, a full iOS 5 MDM solution may not be needed, but
it usually has significant advantages with larger fleets, or more complex
usage scenarios.
MDM Vendors
At the time of writing this guide there were a number of vendors shipping MDM
solutions that have full support for Apple’s MDM protocol and APNS integration.
Some of these MDM solutions focus purely on device policy and monitoring. Others
enhance this functionality, providing additional features via an App and event triggers
for business rules that integrate with Exchange ActiveSync, Certificate Authorities
and Directory Services. Many vendors can manage multi-platform clients. In this
chapter the discussion will be restricted to iOS features.
MDM functions
Once an iOS 5 device is enrolled with an MDM Server, an Apple MDM agent is
activated on the client device. It can then perform a number of tasks without user
interaction, including querying status of the device, and installing or removing
Managed Profiles. The interaction between an MDM server and a device can occur
in two or three main ways:
The MDM server can send an APNS notification to a device.
A device, typically on receipt of a push notification, contacts the MDM server
in an SSL encrypted session and exchanges information using XML. This
52 | D e f e n c e S i g n a l s D i r e c t o r a t e
may be a simple query/response transaction or it may lead to the device
pulling content down from a location the MDM server told it to, such as a
configuration profile or provisioning profiles.
The MDM vendor may also have a client App that can interact with the MDM
server. Such Apps can interact in proprietary ways beyond the functionality
that the MDM protocol allows for. Such Apps do not operate at any elevated
level of privilege, and if available on the App store, are subject to normal App
Store approval processes, but can enhance the functionality and the user
Note that an MDM server cannot install native Apps remotely without some user
intervention. Web apps can be deployed without user intervention by pushing a web
clip to the device. Remote App installation occurs a number of ways:
The MDM server can silently install or remove provisioning profiles to enable
or disable an application from running on a device. The application binary still
needs to be downloaded to the device by some means. Enterprise Apps can
either have a provisioning profile external to the App so it can be
installed/removed, typically via MDM, or have the provisioning profile
embedded within the App itself, which means downloading the App bundle is
sufficient for it to run (if present, the Provisioning Profile is copied from the
App bundle, by the installer, and installed when the App is installed).
The MDM server can silently install or remove a configuration profile that
contains a web clip. If the web clip points to an appropriately constructed web
site, touching on it will download an Enterprise iOS application to the device.
The Web clip can also be the URL for a Web app, in which case it is usable
The MDM solution may also, either via a native app or a web app, provide a
list of approved or recommended App Store Apps, and Enterprise In-House
Apps. When touched by a user, this will open the App Store or web server on
the device for the user to download or purchase.
The MDM can install “Managed Apps” remotely, the user is still required to
accept the install but doesn’t need to authenticate. However, in Australia only
free App Store Apps and enterprise in-house Apps can be installed as
Managed Apps.
53 | D e f e n c e S i g n a l s D i r e c t o r a t e
Appendix A
Security Checklist
The following checklist will assist an agency in ensuring that all key tasks in securely
deploying iOS devices have been completed.
Before Deploying iOS Devices
Develop agency policy and
procedures, including any
restrictions, for the use of iOS devices
that align with Australian government
legislation, policies and standards,
and that adhere to Australian
government requirements.
Effective policies and procedures help to
ensure that an agency considers relevant
issues and operates in accordance with
legislation and whole-of-government
guidelines. Documenting and making
these available to users will help ensure
that users are aware of an agency’s
expectations of them when using mobile
devices. On iOS devices, placing a policy
Web Clip on the device makes it highly
accessible to the user.
Implement processes to security
classify, protectively mark, and
control the flow of information that
may be transmitted to/from the iOS
Filtering solutions at the EAS server can
both filter and mark email based on
header metadata and shorthand notation
in the subject line. Agencies must
security classify and protectively mark all
email and controls must be implemented
at email servers and gateways to restrict
delivery of inappropriately classified
information to and from an agency,
including to mobile devices.
54 | D e f e n c e S i g n a l s D i r e c t o r a t e
Undertake an iOS device preimplementation review.
Agencies deploying iOS devices may
consider undertaking a preimplementation review. This review
would assess the planned deployment
strategy, mitigation controls, policies and
procedures against the requirements
defined in the relevant policy and
guidance documents. DSD can assist in
ensuring the necessary steps have been
Manage Use of iOS Devices
Provide users with training on the use
of iOS devices and security
In many areas of administration, failure to
follow policies and procedures is not a
result of deliberate actions, but a lack of
awareness of requirements. Training in
the appropriate use of devices can assist
users to implement policies and
procedures. The existence of training can
also help distinguish deliberate misuse
from incompetent usage. As part of this
training agencies should also inform
users that these devices are likely to be
an attractive target for thieves, and that
the implications of the information
contained in them being accessed by
others could be detrimental to the
Australian government.
Ensure that users formally
acknowledge their agreement to
adhere to agency specific Acceptable
Usage Policy and procedures.
Users using a mobile device are
responsible for its use. Users must be
aware of and agree in accordance with
the agency’s policy and procedures. The
ramifications of failing to apply those
policies and procedures must also be
clear to users.
55 | D e f e n c e S i g n a l s D i r e c t o r a t e
Ensure that users classify and
protectively mark all email with the
highest classification of the content or
attachment, in accordance with
Australian government standards.
Users must be conscious of the security
classification of information that they are
sending to or from mobile devices.
Agencies must ensure that users classify
and protectively mark all agencyoriginated email or attachments in
accordance with the highest classification
of the content.
Infrastructure Issues
Server infrastructure for EAS, MDM,
CA and Web that supports an iOS
deployment must be controlled, either
directly or under contract, by the
Australian government.
Use of EAS, MDM and CA infrastructure
allows many risks to be mitigated. These
servers should be situated in a controlled
environment, and will permit the
implementation of consistent policy and
device settings. Software as a Service
(SaaS) solutions may not be acceptable
for production deployments.
Agencies must ensure that content is
transferred between an iOS Device
and an agency’s ICT systems in
accordance with Australian
government policy.
Email protective marking filtering
mechanisms must be implemented to
provide a higher level of security by
automatically preventing information of
an inappropriate classification being sent
to a mobile device. These mechanisms
are described in the Implementation
Guide for Email Protective Markings for
Australian government Agencies.
56 | D e f e n c e S i g n a l s D i r e c t o r a t e
Ensure that email originating outside
the agency is not sent to the iOS
device unless it is classified and
labelled appropriately.
Communications originating outside the
agency may also include classified
information. The policies and standards
applied to external communications must
also be applied to internally generated
information. Emails that do not have
protective markings should not be
transmitted to mobile devices. Agency
policy may define a subset, e.g. an
agency may only permit Unclassified
information to be forwarded to a mobile
device. These mechanisms are
described in the Implementation Guide
for Email Protective Markings for
Australian government Agencies.
Review and Audit
Undertake an iOS post
implementation review.
Agencies that deploy iOS devices must
undertake a post implementation review.
This may assist in identifying policy and
implementation inconsistencies and
assess the mitigation controls for
completeness against the Risk
Management Plan (RMP), The System
Security Plan (SSP), Standard Operating
Procedures (SOP) and the
implementation of email protective
marking controls. This review must be
completed within twelve months of the
live production deployment.
Audit compliance with policies and
standards for the use of iOS devices.
Setting out policy without monitoring
compliance is unsound practice. There
should be appropriate internal and – from
time to time – external checks of
compliance with policies regarding the
use of mobile devices. There should also
be regular reviews of internal policies, to
test their currency and adequacy.
57 | D e f e n c e S i g n a l s D i r e c t o r a t e
Appendix B
Configuration Profiles Format
This Appendix provides the references for the format of mobileconfig files for
agencies wishing to create their own tools or custom configurations without deploying
a commercial MDM solution.
Configuration Profiles use the Apple XML DTD and the general property list (plist)
format. A general description of the Apple plist format is available at
To get started with Configuration Profiles, iPhone Configuration Utility (iPCU) can be
used to create a skeleton file that can be modified using the information in this
appendix, or use the examples at
iPhone Configuration Utility is documented in detail here:
lity/ Introduction/Introduction.html
A screen shot of the iPhone Configuration Utility is on the following page, showing
the range of different profile payloads. This document uses the terms payload and
profile. A profile is the whole file that configures certain (single or multiple) settings
on iPhone, iPod touch, or iPad. A payload is an individual component of the profile
58 | D e f e n c e S i g n a l s D i r e c t o r a t e
iPhone Configuration Utility
For further information on configuration profile format, full documentation is
available from:
• featuredarticles/iPhoneConfigurationProfileRef/Introduction/Introduction.html
For further information on configuration profiles, including scripting of iPCU
and sample Ruby code for building a SCEP server that generates profiles on
demand, see: documentation/NetworkingInternet/Conceptual/iPhoneOTAConfiguration/Introduction
59 | D e f e n c e S i g n a l s D i r e c t o r a t e
Appendix C
Sample Scripts
This Appendix provides sample scripts for iOS deployment tasks. The scripts in this
section should be modified to fit agency needs and configurations. featuredarticles/FA_iPhone_Configuration_Utility/Introduction/Introduction.html
Sample C# Script for iPhone Configuration Utility
This sample script demonstrates creating configuration files using iPhone.
Configuration Utility for Windows.
using System;
using Com.Apple.iPCUScripting;
public class TestScript : IScript
private IApplication _host;
public TestScript()
public void main (IApplication inHost)
{ _host = inHost;
string msg = string.Format("# of config profiles : {0}",
IConfigurationProfile profile = _host.AddConfigurationProfile();
profile.Name = "Profile Via Script";
profile.Identifier = "com.example.configviascript";
profile.Organization = "Example Org";
profile.Description = "This is a configuration profile created via the new scripting
feature in iPCU";
// passcode
IPasscodePayload passcodePayload = profile.AddPasscodePayload();
passcodePayload.PasscodeRequired = true;
passcodePayload.AllowSimple = true;
// restrictions
IRestrictionsPayload restrictionsPayload = profile.AddRestrictionsPayload();
restrictionsPayload.AllowYouTube = false;
// wi-fi IWiFiPayload
wifiPayload = profile.AddWiFiPayload();
wifiPayload.ServiceSetIdentifier = "Example Wi-Fi";
wifiPayload.EncryptionType = WirelessEncryptionType.WPA;
wifiPayload.Password = "password";
60 | D e f e n c e S i g n a l s D i r e c t o r a t e
wifiPayload = profile.AddWiFiPayload();
// vpn
IVPNPayload vpnPayload = profile.AddVPNPayload();
vpnPayload.ConnectionName = "Example VPN Connection";
vpnPayload = profile.AddVPNPayload();
// email
IEmailPayload emailPayload = profile.AddEmailPayload();
emailPayload.AccountDescription = "Email Account 1 Via Scripting";
emailPayload = profile.AddEmailPayload();
emailPayload.AccountDescription = "Email Account 2 Via Scripting";
// exchange
IExchangePayload exchangePayload = profile.AddExchangePayload();
exchangePayload.AccountName = "ExchangePayloadAccount";
// ldap
ILDAPPayload ldapPayload = profile.AddLDAPPayload();
ldapPayload.Description = "LDAP Account 1 Via Scripting";
ldapPayload = profile.AddLDAPPayload();
ldapPayload.Description = "LDAP Account 2 Via Scripting";
// webclip
IWebClipPayload wcPayload = profile.AddWebClipPayload();
wcPayload.Label = "Web Clip 1 Via Scripting";
wcPayload = profile.AddWebClipPayload();
wcPayload.Label = "Web Clip 2 Via Scripting";
Sample AppleScript for iPhone Configuration Utility
This sample script demonstrates creating configuration files using iPhone
Configuration Utility for Mac OS X.
tell application "iPhone Configuration Utility"
log (count of every configuration profile)
set the Profile to make new configuration profile with properties{displayed
name: “Profile Via Script", profile identifier:"com.example.configviascript",
organization:"Example Org.", account description:"This is a configuration profile
created via AppleScript"} with properties {label:"Web Clip Account 1 with properties
{label:"Web Clip Account 2”}
tell theProfile
make new passcode payload with properties {passcode required:true,
simple value allowed:true}
make new restrictions payload with properties {YouTube
make new WiFi payload with properties {service set
identifier:"Example Wi-Fi", security type:WPA, password:"password"}
61 | D e f e n c e S i g n a l s D i r e c t o r a t e
set theWiFiPayload to make new WiFi payload
delete theWiFiPayload
make new VPN payload with properties {connection name:"Example
VPN Connection"}
set theVPNPayload to make new VPN payload
delete theVPNPayload
make new email payload with properties {account description:"Email
Account 1 Via Scripting"}
make new email payload with properties {account description:"Email
Account 2 Via Scripting"}
make new Exchange ActiveSync payload with properties {account
make new LDAP payload with properties {account description:"LDAP
Account 1 Via Scripting"}
make new LDAP payload with properties {account description:"LDAP
Account 2 Via Scripting"}
make new web clip payload Via Scripting"}
make new web clip payload Via Scripting"}
end tell
end tell
62 | D e f e n c e S i g n a l s D i r e c t o r a t e
Appendix D
Example Scenarios
This Appendix describes hypothetical scenarios showing how the various techniques
can be combined.
Unclassified Example
An art gallery wishes to use iPod touches as an interactive tour guide for Unclassified
information at a specific site. The tour guide information is largely contained within a
single App.
The Gallery purchased an Enterprise Developer Agreement, and uses this to codesign the App they have had developed by a contractor.
They set up a Wi-Fi network for the site, and use a Kiosk with a locked down
instance of iTunes, and OTA App and profile provisioning from a secured web server
to deploy, manage and reset devices during use with minimal effort.
Unclassified (DLM) Example
An agency wants to use iPads as a field-based information gathering tool for its
users. Information will come from a mix of existing web sites and with some data
entry fed into an existing system with an XML interface using an Enterprise In-House
App the agency has developed. The devices will also allow users to send and
receive email in the field. The agency’s primary WAN is classified “PROTECTED”.
In this case the agency uses a combination of an MDM server, Exchange
ActiveSync, and a 3rd party gateway filter. These enable the agency to control policy
on the devices, control email that is sent to the devices and implement protective
markings on email sent from the devices. Access to the limited intranet sites with
Unclassified (DLM) data is controlled by a reverse proxy. The custom App and its
supporting server infrastructure undergo a separate TRA (Threat Risk Assessment).
A Wi-Fi network configured according to relevant ISM government system (G)
controls is provided at selected locations to support OTA provisioning and updating
of devices.
An agency has decided to issue iPhones for their mobile fleet. Their users require
access to their PROTECTED email and attachments, as well as access to a
PROTECTED intranet.
The IT team will use Apple Configurator to configure the iPhones before they are
issued to users. The iPhones will be configured as Supervised devices and will be
pre-enrolled with the agency’s MDM server.
63 | D e f e n c e S i g n a l s D i r e c t o r a t e
The iPhones will connect to the agency’s exchange server using a client certificate
for authentication. The VPN will be configured as “On-Demand” with certificate
authentication and the whitelist will be a regular expression that matches all top level
domains – this forces all traffic over the VPN. The agency has a custom APN for their
mobile data traffic and the VPN proxy is set to the agency’s proxy so that all internet
traffic flows through the agencies certified gateway.
The agency will require all users to sign an acceptable use policy that requires them
to install OTA updates when they are available, compliance will be monitored by the
IT team using the MDM.
64 | D e f e n c e S i g n a l s D i r e c t o r a t e
Appendix E
Risk Management Guide
This Appendix provides a guide to typical risks associated with mobile devices and
recommended mitigation measures.
Australian Government Information Security Manual (ISM)
This appendix should be read in conjunction with the ISM, available from the DSD
iOS devices do not completely comply with all requirements described within the
Mobile Device Risks
Typical risks, the recommended mitigation measures and the pre-conditions for those
mitigation measures are covered in the table below. There are several residual risks
in ISM policy that cannot be completely mitigated by technical controls. Agencies will
need to assess, accept and manage any residual risks and develop appropriate
policy guidance.
iOS 5 does not have a local firewall. This is partially mitigated by firewalling at
the network layer, and significantly mitigated by the sandboxed runtime
environment in iOS.
iOS 5 allows the user to deliberately connect to an untrusted Wi-Fi network.
Note that iOS devices will not autoconnect to any unknown Wi-Fi network.
The only mitigations available at this time are pre-configured settings, user
education and AUP.
iOS 5 allows the user to deliberately enable or disable the radios in the device
- there is no method for a configuration profile to force a radio off. The only
mitigations available at this time are user education, AUP or hardware
modification (the latter being permanent and will void the warranty).
iOS 5 has no “always-on” setting for VPN. It is either manually initiated, or ondemand based on a whitelist. Options to mitigate this for PIM data (if EAS
and/or VPN on demand are assessed as insufficient mitigations) include
using a 3rd party PIM solution, filtering at the EAS, or using approved VDI
solution to access sensitive data. For web site access, an SSL reverse proxy
may be more suitable than VPN in some scenarios.
65 | D e f e n c e S i g n a l s D i r e c t o r a t e
Device lost, still on
Strong passcode, data protection
enabled, remote wipe, Find My
Configuration Profiles,
EAS or MDM Server
in a network reachable
location or iCloud
Device lost, off
Strong passcode, local wipe, data
protection enabled.
Configuration Profiles,
Device restored to iOS
5 prior to use in field.
Device lost, casual
access attempt
Strong passcode, local Wipe, data
protection enabled.
Configuration Profiles,
Device restored to iOS
5 prior to use in field.
Device lost, forensic
access attempt
without passcode
Strong passcode, local wipe, use of
Supervised mode, data protection
enabled, App usage of appropriate
data protection class9.
Configuration Profiles,
Device restored to iOS
5 prior to use in field.
Device in Supervised
Strong passcode, data protection
enabled, use of devices with
hardware cryptographic module,
use of MDM console, use of VDI
infrastructure. Use of Supervised
mode, MDM App or enterprise
Apps with “canary” code to detect
and report jailbreaking, AUP should
prohibit jailbreaking.
Jailbreaking from host
computer when device
passcode is known is
still likely to be
feasible, unless
supervised mode is
Information for developers implementing data protection classes is available from:
66 | D e f e n c e S i g n a l s D i r e c t o r a t e
Malicious runtime
Code signing, memory and
filesystem sandboxing, use of VDI
infrastructure, no-execute heap,
disable user-added applications, do
not jailbreak operational devices.
In-house application
capability, CA
infrastructure. May
mitigate on lower
security levels by
“approved” lists and
MDM monitoring as
Users cut and paste
agency data into a
public email
account (e.g. Yahoo
or Gmail ) and sent
it from the device.
On iOS 5 disable the creation of
separate email accounts, and
restrict access to webmail via
custom APN and agency proxy,
disable screen shots on device via
Configuration Profile, filter sensitive
mail or attachments at the EAS
gateway, use of VDI for sensitive
email, containing agency email to a
third party email App container.
Configuration Profiles,
use of agency proxy.
Network trust
Use of 802.1X NAC, IPSEC or SSL
VPN, encrypted VDI.
Use of 802.1X with CA
& NAC on Wireless,
VPN on Demand with
client certificates for
agency network
access, use of SSL
reverse proxy for low
security data.
Note that any data
that is displayed on
the screen of any
device can be
photographed or video
recorded by a camera,
and sent via other
means. This kind of
leakage by deliberate
action generally
cannot be mitigated
against for a mobile
67 | D e f e n c e S i g n a l s D i r e c t o r a t e
Use of Custom APN on 3G,
802.1X, SSL VPN.
A custom APN is an
arrangement with the
agency telephone
carrier. This allows
devices on 3G data to
have a deterministic
IP range that can be
more easily firewalled
or proxied.
Data compromise
via host computer
Force encrypted profile onto device, SSL CA infrastructure
user education, physical security of to sign and encrypt
backup host, iTunes in host SOE.
profiles into agency
chain of trust.
Potentially allow use
of locked down iTunes
configuration on
agency computers so
backup resides on
agency assets.
Data compromise
via Bluetooth
OS 5 only includes four or six of the
26 Bluetooth profiles, depending on
device, and specifically does not
include file transfer related
Bluetooth profiles. Included profiles
are for microphone, speakers, and
human input devices, as well as
Apps that use a Bluetooth PAN.
Apps that share
information via
Bluetooth PAN not
approved for use on
devices where this
vector is a concern.
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Appendix F
Firewall Rules
Several firewall rules may need to be implemented to allow correct functionality.
Depending on what functionality is required from iOS devices, MDM servers and
iTunes several firewall rules may need to be implemented.
Firewall ports
iTunes and iOS devices may need firewall rules adjusted, depending on the
functionality required, or allowed, on an intranet. The main knowledge base articles
describing ports required by Apple devices are given below, with a summary around
iOS and iTunes in the following table below:
DNS name
Online Certificate Status for code
signing certificates, checked
periodically while online and after
device reboot.
Certificate Revocation List for
codesigning certificates, checked
periodically while online and after
device reboot.
2195 (outbound
push e.g. MDM)
2196 (for devices
to receive)
Apple Push Notification Service
(for a development environment
is used instead).
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2195 (outbound
push - e.g. MDM)
2196 (for devices
to receive)
Apple Push Notification Service
(for a development environment
is used instead).
80, 443
iTunes Store, Device Activation.
80, 443
iTunes Store, Device Activation.
80, 443
iTunes U.
80, 443
iTunes Music Store and album
cover media servers.
80, 443
iTunes Store, Device Activation.
80, 443
iTunes Store, Device Activation.
80, 443
iTunes Store, Device Activation.
80, 443
Device Activation.
80, 443
Verification of digital signatures of
iTunes purchased content.
80, 443
Verification of digital signatures of
iTunes purchased content.
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80, 443
iTunes Music Store and album
cover media servers.
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