Version 1-0
© 2018 Citrix Systems, Inc. All rights reserved
Common Criteria Security Target
for
Citrix XenDesktop 7.15 LTSR Platinum
Edition and Citrix XenApp 7.15 LTSR
Platinum Edition
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0. Preface
0.1 Objectives of Document
This document presents the Common Criteria (CC) Security Target (ST) to express the
security and evaluation requirements for the Citrix XenDesktop 7.15 LTSR Platinum Edition
and Citrix XenApp 7.15 LTSR Platinum Edition products.
The products are designed and manufactured by Citrix Systems, Inc.
(http://www.citrix.com/).
The Sponsor and Developer for the evaluation is Citrix Systems, Inc.
0.2 Scope of Document
The scope of the Security Target within the development and evaluation process is described
in the Common Criteria for Information Technology Security Evaluation [CC]. In particular,
a Security Target defines the IT security requirements of an identified TOE and specifies the
functional and assurance security measures offered by that TOE to meet stated requirements
[CC1, Section C.1].
Security Functional Requirements (SFRs), as defined in [CC2], are the basis for the TOE IT
security functional requirements expressed in this Security Target. These requirements
describe the desired security behaviour expected of a TOE and are intended to meet the
security objectives as stated in this Security Target. Security Functional Requirements
express security requirements intended to counter threats in the assumed operating
environment of the TOE, and cover any identified organisational security policies and
assumptions.
0.3 Intended Readership
The target audience of this ST are consumers, developers, certifiers and evaluators of the
TOE, additional information can be found in [CC1, Section 6.2].
0.4 Related Documents
Common Criteria1
[CC1] Common Criteria for Information Technology Security Evaluation,
Part 1: Introduction and General Model,
CCMB-2012-09-001, Version 3.1 Revision 5, April 2017.
[CC2] Common Criteria for Information Technology Security Evaluation,
Part 2: Security Functional Components,
1
For details see http://www.commoncriteriaportal.org/
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CCMB-2012-09-002, Version 3.1 Revision 5, April 2017.
[CC3] Common Criteria for Information Technology Security Evaluation,
Part 3: Security Assurance Components,
CCMB-2012-09-003, Version 3.1 Revision 5, April 2017.
[CEM] Common Methodology for Information Technology Security Evaluation,
Evaluation Methodology,
CCMB-2012-09-004, Version 3.1, Revision 5, April 2017.
Note: The 3 separate parts of Common Criteria are also referred to collectively as “[CC]”.
0.5 Significant Assumptions
None
0.6 Abbreviations
Acronym Meaning
AES Advanced Encryption Standard
DDC Delivery Controller (the leading ‘D’ is
present for historical reasons and to avoid
potential confusion with ‘Domain
Controller’)
EAL Evaluation Assurance Level
ICA Independent Computing Architecture
LAN Local Area Network
OSP Organisational Security Policy
PP Protection Profile
SAR Security Assurance Requirement
SFP Security Function Policy
SFR Security Functional Requirement
ST Security Target
TLS Transport Layer Security
TOE Target of Evaluation
TSF TOE Security Functionality
VDA Virtual Delivery Agent
WCF Windows Communication Foundation
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0.7 Glossary
Term Meaning
Access permissions for virtual desktops configuration data within the TOE which determines which
virtual desktops each user is permitted to access.
Access permissions for (published)
applications
configuration data within the TOE which determines which
published applications each user is permitted to access (cf.
Permitted Published Applications (q.v.)).
Assurance grounds for confidence that a TOE meets the SFRs [CC1]
Catalog a collection of machines of the same Machine Type. Catalogs
are managed as a single entity. Desktops or servers from more
than one catalog can be allocated to a delivery group.
Citrix Receiver installed on user devices, this is a client that provides direct
ICA connections to server or desktop Virtual Delivery Agents.
Citrix Studio provides the administration interface to the Delivery Controller
for managing access permissions for virtual desktops, virtual
desktop configuration data, published applications, published
application configuration data (permitted published
applications for each application user) and Endpoint data
access control policy.
Configdata configuration data within the TOE; which includes access
permissions for virtual desktops and published applcations,
Virtual Desktop configuration data and Endpoint data access
control policy. See section 3.1.
Controller Delivery Controller (q.v.)
Delivery Controller authenticates administrators and users, manages the assembly
of users’ virtual desktop and application environments and
brokers connections between users and their virtual desktops
and applications. In Citrix documentation often identified
simply as the Controller.
Delivery Group an administrative grouping of machines to supply desktops
and/or applications that are allocated to users or groups of
users. Machines from one or more catalogs are used to create
the delivery group. Users can be given permissions to access
one or more delivery groups, but in the evaluated configuration
each user is given access to only a single desktop delivery
group and a single application delivery group.
Domain pass-through a means of authentication in which single sign-on is provided
using the domain credentials used to log on to a domain-joined
client running Citrix Receiver.
Endpoint data access control policy a set of rules, configured within the TOE, which determine
whether or not a user can access User Device resources from
within a virtual desktop or published application: specifically
clipboard, local drives, USB devices; used in conjunction with
input evidence values to determine specific settings for any
particular virtual desktop.
Evaluation Assurance Level an assurance package, consisting of assurance requirements
drawn from CC Part 3, representing a point on the CC
predefined assurance scale. [CC1]
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Term Meaning
ICA File a file used with the Independent Computing Architecture,
which contains configuration information enabling a client to
connect to a server.
Independent Computing Architecture a presentation services protocol, used to present input
(keystrokes, mouse clicks etc.) to the virtual desktop and
published applications for processing and to return output
(display, audio etc.) to the Citrix Receiver running on the
client.
License Server a server that issues licenses for Citrix products.
Machine Type defines the machine type (desktop or server OS) as well as a
number of other properties relating to how machines in a
catalog are provisioned, allocated and managed.
In the evaluated configuration only manually provisioned
machine types will be used. The manually provisioned machine
type enables the use of XenDesktop and XenApp to manage
and deliver user desktops and applications that have already
been migrated to VMs in the data centre.
In the evaluated configuration, only static pre-assigned desktop
machines are used, which means that each user is assigned a
specific virtual desktop by an administrator, and the user
receives this virtual desktop at each logon.
Object a passive entity in the TOE, that contains or receives
information, and upon which subjects perform operations.
[CC1]
Operational Environment the environment in which the TOE is operated. [CC1]
Organisational Security Policy a set of security rules, procedures, or guidelines imposed (or
presumed to be imposed) now and/or in the future by an actual
or hypothetical organisation in the operational environment.
[CC1]
Permitted Published Applications The set of published applications to which an authorised User
has been granted access.
(See also Published Applications)
Protection Profile an implementation-independent statement of security needs for
a TOE type. [CC1]
Provisioning act of creating new virtual desktops and/or published
applications, including the operating system image for the
desktops and related configuration.
Published Applications The applications that administrators can configure to be
accessible by authorised Users. The definition also includes
data and resources associated with a given application (e.g.
data defining the initial configuration or appearance of an
application). Different authorised Users may have access to
different sets of applications (see Permitted Published
Applications).
Security Assurance Requirement a description of how assurance is to be gained that the TOE
meets the SFRs. [CC1]
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Term Meaning
Security Attribute a property of subjects, users (including external IT products),
objects, information, sessions and/or resources that is used in
defining the SFRs and whose values are used in enforcing the
SFRs. [CC1]
Security Function Policy a set of rules describing specific security behaviour enforced
by the TSF and expressible as a set of SFRs. [CC1]
Security Functional Requirement a translation of the security objectives for the TOE into a
standardised language[CC1], describing the desired security
behaviour expected of a Target of Evaluation (TOE) [CC2].
Security Objective a statement of intent to counter identified threats and/or satisfy
identified organisation security policies and/or assumptions.
[CC1]
Security Target an implementation-dependent statement of security needs for a
specific identified TOE. [CC1]
Site a collection of Catalogs, Delivery Groups, Published
Applications, virtual desktops and Configdata that are defined,
managed and accessed via the same Delivery Controller, and
which are stored within a common, shared database. In the
evaluated configuration, there will only be a single application
delivery group and a single desktop delivery group defined in
the site.
StoreFront a server that provides a user with an interface to an self-service
store which allows them to subscribe to and launch their
chosen apps and desktops following authentication.
Subject an active entity in the TOE that performs operations on objects.
[CC1]
Target of Evaluation a set of software, firmware and/or hardware possibly
accompanied by guidance. [CC1]
TOE Security Functionality a set consisting of all hardware, software, and firmware of the
TOE that must be relied upon for the correct enforcement of
the SFRs. [CC1]
Transport Layer Security an open, non-proprietary, standardised protocol providing
server authentication, data stream encryption and message
integrity checks for a TCP/IP connection.
TSF Data data created by and for the TOE, that might affect the operation
of the TOE. [CC1]
User Data data created by and for the user, that does not affect the
operation of the TSF. [CC1]
User Device a device (in the evaluated configuration this will be a PC
running Windows) used by a user to gain access to their virtual
desktops or published applications.
Userdata user data within the TOE. See section 3.1.
Virtual Delivery Agent installed on virtual desktops and servers running Microsoft
Remote Desktop Services, this enables direct ICA connections
between the virtual desktop or published applications running
on the server and users’ User Devices.
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Term Meaning
Virtual Desktop a desktop operating system running on a virtual machine on a
virtualised server, personalised for a desktop user.
Virtual Desktop configuration data configuration data within the TOE which determines the
configuration and characteristics of each virtual desktop.
VM Host a server providing the virtual machines on which the virtual
desktops and virtual applications are running.
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Contents
1. ST Introduction............................................................................................................................................... 10
1.1 ST and TOE Reference Identification ....................................................................................................... 10
1.2 TOE Overview .......................................................................................................................................... 10
1.2.1 Usage and major features of the TOE.................................................................................................. 10
1.2.2 TOE Type ............................................................................................................................................ 11
1.2.3 Required non-TOE hardware/software/firmware ................................................................................ 12
1.3 TOE Description ....................................................................................................................................... 13
1.4 TOE Boundaries........................................................................................................................................ 15
1.4.1 Physical Boundary............................................................................................................................... 15
1.4.2 Logical Boundary ................................................................................................................................ 16
1.4.3 Features and functions not evaluated................................................................................................... 17
2. CC Conformance ............................................................................................................................................ 20
3. Security Problem Definition ........................................................................................................................... 21
3.1 Assets ........................................................................................................................................................ 21
3.2 Users and Subjects..................................................................................................................................... 21
3.3 Threats....................................................................................................................................................... 22
3.3.1 Attacks on the TOE ............................................................................................................................. 22
3.4 Organisational Security Policies................................................................................................................ 22
3.5 Assumptions.............................................................................................................................................. 23
4. Security Objectives ......................................................................................................................................... 24
4.1 Security Objectives for the TOE ............................................................................................................... 24
4.2 Security Objectives for the Environment .................................................................................................. 25
4.2.1 Security Objectives for the Technical Environment............................................................................ 25
4.2.2 Security Objectives for the Procedural Environment .......................................................................... 26
4.3 SPD/Objectives Rationale ......................................................................................................................... 27
4.3.1 T.Attack_DesktopOrApp..................................................................................................................... 28
4.3.2 T.Attack_Userdata............................................................................................................................... 28
4.3.3 T.Access_DesktopOrApp .................................................................................................................... 28
4.3.4 T.Access_Userdata .............................................................................................................................. 29
4.3.5 T.Intercept............................................................................................................................................ 30
4.3.6 T.Spoof................................................................................................................................................ 30
4.3.7 T.Attack_Configdata ........................................................................................................................... 30
4.3.8 P.Restrictions....................................................................................................................................... 31
4.3.9 A.Physical............................................................................................................................................ 31
4.3.10 A.Config_Endpoint.............................................................................................................................. 31
4.3.11 A.Operations_Security......................................................................................................................... 31
4.3.12 A.VM_Host ......................................................................................................................................... 31
4.3.13 A.Third_Party_SW .............................................................................................................................. 31
5. IT Security Requirements ............................................................................................................................... 32
5.1 Conventions............................................................................................................................................... 32
5.2 Security Functional Requirements ............................................................................................................ 32
5.2.1 Authentication ..................................................................................................................................... 32
5.2.1.1 FIA_ATD.1/User User attribute definition .................................................................................... 32
5.2.1.2 FIA_UID.2/User User identification before any action ................................................................. 32
5.2.2 Authorisation ....................................................................................................................................... 33
5.2.2.1 FMT_SMR.1/Authorise Security management roles..................................................................... 33
5.2.2.2 FMT_SMF.1/Authorise Specification of management functions .................................................. 33
5.2.2.3 FDP_ACC.1/Application Subset access control ........................................................................... 34
5.2.2.4 FDP_ACF.1/Application Security attribute based access control................................................. 34
5.2.2.5 FMT_MSA.1/Application Management of Security Attributes.................................................... 34
5.2.2.6 FMT_MSA.3/Application Static attribute initialisation................................................................ 35
5.2.2.7 FDP_ACC.1/Desktop Subset access control.................................................................................. 35
5.2.2.8 FDP_ACF.1/Desktop Security attribute based access control ....................................................... 35
5.2.2.9 FMT_MSA.1/Desktop Management of security attributes ............................................................ 35
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5.2.2.10 FMT_MSA.3/Desktop Static attribute initialisation ...................................................................... 36
5.2.2.11 FDP_ACC.1/Resources Subset access control............................................................................... 36
5.2.2.12 FDP_ACF.1/Resources Security attribute based access control .................................................... 36
5.2.2.13 FMT_MSA.1/Resources Management of security attributes......................................................... 37
5.2.2.14 FMT_MSA.3/Resources Static attribute initialisation ................................................................... 37
5.2.3 Communications.................................................................................................................................. 38
5.2.3.1 FPT_ITT.1 Basic Internal TSF Data Transfer Protection .............................................................. 38
5.3 Security Assurance Requirements............................................................................................................. 38
5.4 Objectives/SFRs Rationale........................................................................................................................ 40
5.4.1 O.Auth_User........................................................................................................................................ 40
5.4.2 O.Auth_Server..................................................................................................................................... 40
5.4.3 O.Desktop............................................................................................................................................ 40
5.4.4 O.Application ...................................................................................................................................... 41
5.4.5 O.Secure_Setup_Data.......................................................................................................................... 41
5.4.6 O.Secure_User_Data ........................................................................................................................... 41
5.4.7 O.Config_Access................................................................................................................................. 41
5.4.8 O.Endpoint_Resource.......................................................................................................................... 42
5.5 SFR Dependencies Analysis...................................................................................................................... 42
6. TOE Summary Specification .......................................................................................................................... 44
6.1 Administrator access control..................................................................................................................... 44
6.2 Administration of virtual desktop and published application authorisation .............................................. 44
6.3 Desktop user and Application user access control .................................................................................... 45
6.4 User Device resource access control ......................................................................................................... 46
6.5 Secure communications............................................................................................................................. 46
Figures / Tables
Figure 1: XenDesktop and XenApp Components .........................................................................................13
Figure 2: TOE Physical boundary .................................................................................................................15
Figure 3: Logical boundaries.........................................................................................................................17
Table 1: Threats/OSP/Assumptions addressed by Security Objectives........................................................27
Table 2: Security Assurance Requirements..................................................................................................38
Table 3: Summary of Objectives/SFRs Rationale........................................................................................40
Table 4: Analysis of SFR Dependencies......................................................................................................43
Table 5: Summary of SFRs satisfied by TOE Functions..............................................................................44
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1. ST Introduction
In this section, the introduction to the ST is provided.
1.1 ST and TOE Reference Identification
TOE Reference: Citrix XenDesktop 7.15 LTSR Platinum Edition and Citrix
XenApp 7.15 LTSR Platinum Edition
ST Reference: Citrix XenDesktop 7.15 LTSR Platinum Edition and Citrix
XenApp 7.15 LTSR Platinum Edition Security Target
ST Version: 1-0
ST Date: 15 January 2018
Assurance Level: EAL2 augmented by ALC_FLR.2 Flaw Reporting Procedures
1.2 TOE Overview
1.2.1 Usage and major features of the TOE
Citrix XenDesktop 7.15 LTSR Platinum Edition and Citrix XenApp 7.15 LTSR Platinum
Edition (hereinafter referred to as “XenDesktop” and “XenApp” respectively) are
virtualisation products that centralise and deliver Microsoft Windows virtual desktops and/or
applications as a service to users anywhere. Applications hosted on Microsoft Windows
Server 2016 and personalised virtual desktops hosted on Microsoft Windows 102
can be run
on demand each time they log on. This ensures that performance never degrades, while the
high speed delivery protocol provides unparalleled responsiveness over any network.
XenDesktop and XenApp deliver a high definition user experience over any connection,
including high latency wide area networks.
When used in the full XenDesktop configuration, the TOE gives access to both virtual
desktops and published applications. When used in the XenApp configuration, the TOE gives
access only to published applications. Note that the evaluated configuration of the product is
defined in [CCECG], and specific limitations to the scope of the TOE are listed in section
1.4.3, Features and functions not evaluated.
The open architecture of XenDesktop and XenApp offers choice and flexibility of
virtualisation platform and user devices. XenDesktop and XenApp integrate with various
server virtualisation products. XenDesktop works out-of-the-box with desktop appliances
from every major thin client vendor. Users can also access their virtual desktops and
published applications from most common client devices. This means that there is no vendor
2
Note that only virtual desktops running on desktop Virtual Delivery Agents are included in the scope of the
evaluation; desktops running on server Virtual Delivery Agents are excluded.
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lock-in for virtualisation or user devices3
. (See sections 1.2.3, 1.4.3, and [CCECG] for
details of the evaluated configuration)
XenDesktop simplifies desktop lifecycle management by enabling administrators to manage
service levels with built-in desktop performance monitoring, and to deliver applications
separately to the underlying desktop image using virtualisation. The entire desktop and
application lifecycle is managed in one location, simplifying desktop provisioning, patching,
security, and updates.
Although the desktops and applications are virtual, running on remote servers, the user
experience is equivalent to that of a local Windows desktop. From the user’s perspective,
logging on to a virtual desktop is the same as logging on to a local desktop. Users enter their
credentials once and are connected to their desktops and applications.
XenDesktop and XenApp provide the following key security features:
• Authentication of desktop and application users. The TOE requires users to be
authenticated before granting them access to virtual desktops and/or applications. Once
authenticated, users are provided with a reliable connection to a virtual desktop that
incorporates their personal settings (for XenDesktop only), and access to their
permitted published applications, regardless of the User Device or location.
• Authenticated administrators. Only authenticated administrators can use the access
management facilities.
• Access Management. Administrators can assign users to virtual desktops and
published applications, and manage the connections to the virtual desktops and
published applications. Provisioning new users is simply a matter of creating an Active
Directory user account and associating the account with a dedicated desktop image
and/or set of permitted published applications.
• Control over use of User Device resources. Centralised control policies, set by
administrators, determine whether users can access local User Device resources such as
the clipboard, local drives, or USB devices, from their virtual desktop and applications.
• Secure communications. High performance, standards-based encrypted transmissions
are used for communications between server components, and between User Device
and server components.
1.2.2 TOE Type
Desktop and Application Virtualisation.
3
Although XenDesktop supports many different user devices only Microsoft Windows user devices are included
in the evaluated configuration
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1.2.3 Required non-TOE hardware/software/firmware
For Citrix StoreFront including the StoreFront Management Console, a server is required
with the following software:
• Microsoft Windows Server 2016, Standard Edition
• Microsoft .NET Framework 4.6
• Microsoft Internet Information Server (IIS) 10.0
• Microsoft ASP.NET 4.6
Citrix License Server 11.14.
For the Delivery Controller including Citrix Studio, a server is required with the following
software:
• Microsoft Windows Server 2016, Standard Edition
• Microsoft .NET Framework 4.6
The Delivery Controller requires a Database with the following software:
• Microsoft SQL Server 2016
• Microsoft Windows Server 2016, Standard Edition.
A User Device will be a PC with the following software:
• Microsoft Windows 10 Enterprise, 64-bit.
• Microsoft Internet Explorer version 11.
Each Desktop Virtual Delivery Agent for the virtual desktop will require the following
software (used in XenDesktop only):
• Microsoft Windows 10 Enterprise, 64-bit.
• Microsoft Internet Explorer version 11.
Each Server Virtual Delivery Agent for the virtual applications will require the following
software:
• Microsoft Windows Server 2016, Standard Edition.
Access to the domain controller is required, which will be a Microsoft server in the
environment running:
• Microsoft Active Directory Server in Windows Server 2016 native mode.
If multi-factor authentication (MFA), such as smart cards, is required, appropriate readers and
drivers are required on endpoints, and appropirate middleware is required to integrate the
multi-factor authentication with the domain controller. The TOE relies on the operational
environment to provide user authentication. This may take the form of passwords or
supported multi-factor authentication, including smart cards, depending on the customer’s
environment and requirements.
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The TOE also requires the use of a hypervisor on the Delivery Controller, creating and
maintaining a virtual machine for each virtual desktop. The only requirement placed on the
hypervisor by this Security Target is that the selected hypervisor should meet A.VM_Host
(see section 3.5) and OE.Config_VM_Host (see section 4.2.1).
Testing was performed using the Citrix XenServer 7.1 Long Term Service Release (LTSR)
hypervisor. Other hypervisors are supported but were not included in Common Criteria
testing. A list of hypervisor versions supported for XenApp 7.15 LTSR and XenDesktop 7.15
LTSR is included in the System requirements article in the XenApp and XenDesktop 7.15
LTSR product documentation available at https://docs.citrix.com.
1.3 TOE Description
XenDesktop and XenApp provide a complete virtual desktop and/or application delivery
system by integrating several distributed components with advanced configuration tools that
simplify the creation and real-time management of the virtual desktop infrastructure and
published applications hosted on servers running Remote Desktop Services.
Figure 1: XenDesktop and XenApp Components
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The core components of XenDesktop and XenApp (illustrated in Figure 1) are:
• Delivery Controller. Installed on servers in the data centre, the controller requires that
users are authenticated, manages the assembly of virtual desktop environments and
servers hosting published applications, and brokers connections between users and their
virtual desktops and applications.
• Virtual Delivery Agent. Installed on virtual desktops and servers hosting published
applications, the agent enables direct ICA (Independent Computing Architecture)
connections between the virtual desktop and servers hosting published applications and
the end user’s User Device.
• Citrix Receiver. Installed on user devices, the Citrix Receiver enables direct ICA
connections from user devices to virtual desktops and published applications.
• StoreFront. Installed on a server in the data centre, StoreFront is used to give
authorised users access through the Web or intranet to the virtual desktops and
applications that they are authorised to use. Users log on to StoreFront using an
Internet browser and are given the ICA file that the Citrix Receiver needs to connect to
the Virtual Delivery Agent for access to an authorised virtual desktop or application.
StoreFront is also accessed from an Internet browser running within the virtual desktop
to launch virtual applications the user is authorised to access.
• StoreFront Management Console. This provides an administration interface to
StoreFront, making use of Windows authentication for administrators. It provides
administrators with functions to manage the configuration of StoreFront, including
setting the user authentication method. This is installed on the StoreFront server.
• Citrix Studio. This provides an administration interface to the Delivery Controller,
making use of Windows authentication for administrators. It provides administrators
with a number of functions, to manage the configuration of virtual desktops and
applications, manage users’ access permissions for virtual desktops and applications
and to manage the Endpoint data access control policy. This is installed on the
Delivery Controller.
• Database. This stores the Configdata managed by the administrators with the Citrix
Studio, including the Endpoint data access control policy, configuration of virtual
desktops, desktop users’ access permissions for virtual desktops, lists of permitted
published applications, and access permissions for administrators, as well as data used
by the Delivery Controller to manage virtual desktops, users and sessions.
The product configuration in this ST is an internal deployment with no external access: the
clients and servers are expected to be running within a LAN.
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1.4 TOE Boundaries
1.4.1 Physical Boundary
The physical boundary of the TOE encompasses the TOE Server components and the TOE
Client component, as illustrated in Figure 2. The TOE Server components comprise the
Delivery Controller (including Citrix Studio), StoreFront (including StoreFront Management
Console), the Database and the Virtual Delivery Agents. The TOE Client component is the
Citrix Receiver running on a User Device or Desktop Virtual Delivery Agent.
Figure 2: TOE Physical boundary
Developer documentation
• Common Criteria Evaluated Configuration Guide for Citrix XenDesktop 7.15 LTSR
Platinum Edition and Citrix XenApp 7.15 LTSR Platinum Edition, 11 January 2018
[CCECG]
• Common Critera-specific documentation is provided at https://www.citrix.com/security in
the Common Criteria section.
• Citrix product documentation is provided at https://docs.citrix.com/.
Version 1-0 Page 16 of 46
While administrators are expected to make use of the online documentation as a whole, the
following sections of the online documentation are specifically relevant to the evaluated
configuration:
For documentation about: From the left menu on docs.citrix.com, navigate to:
Licensing XenApp and XenDesktop > Licensing > Licensing 11.14
Citrix Receiver for
Windows
Citrix Receiver > Receiver for Windows > Citrix Receiver for
Windows 4.9 LTSR
StoreFront XenApp and XenDesktop > StoreFront > StoreFront 3.12
XenApp and XenDesktop
Version 7.15 LTSR
XenApp and XenDesktop > XenApp and XenDesktop 7.15
Long Term Service Release
1.4.2 Logical Boundary
XenDesktop and XenApp are offered in various editions that provide different features. The
evaluated TOE consists of Citrix XenDesktop 7.15 LTSR Platinum Edition and Citrix
XenApp 7.15 LTSR Platinum Edition, including:
• Delivery Controller 7.15.0.15097
• Citrix Studio 7.15.0.93
• StoreFront (including StoreFront Management Console) 3.12.0.17
• Virtual Delivery Agent 7.15.0.15097
• Citrix Receiver 4.9.0.2539 with Online Plug-in 14.9.0.2539
Customers download all components from the Citrix web site (https://www.citrix.com) in
accordance with the detailed delivery information provided in [CCECG] section “Download
and Verify the Installation Media.”
These are all required to belong to the same Active Directory domain, as are all users and
administrators.
The Citrix Receiver runs on the User Device and virtual desktops4
, while the other
components run on servers (in a variety of possible configurations). The logical boundaries
4
Note that when making a double hop connection to start a published application session then the Citrix
Receiver is run on the User Device to start the virtual desktop session in the first hop, and another instance of
(This footnote continues on the next page)
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of the TOE are illustrated below in Figure 3, where elements shown shaded are components
of the TOE.
Figure 3: Logical boundaries
1.4.3 Features and functions not evaluated
The Citrix XenServer hypervisor was used in the environment for testing, but is not part of
the TOE and is therefore not included in this evaluation. (Various other hypervisors are
supported, please see section 1.2.3 for additional information.)
The following Citrix components should not be installed and are therefore not evaluated:
• Citrix NetScaler Gateway – offers secure remote access, not used in the evaluated
configuration;
• Citrix Provisioning Services – optimises provisioning of virtual desktops, not used in
the evaluated configuration;
the Citrix Receiver is then run from within the virtual desktop in the Virtual Delivery Agent on the second hop.
To avoid excessive complexity in the diagram, this second instance of the Citrix Receiver is not shown in Figure
3.
Version 1-0 Page 18 of 46
• Citrix Profile Management – high performance user personalisation method, not used in
the evaluated configuration;
• Citrix NetScaler SD-WAN – accelerator for improved performance on wide area
networks, not used in the evaluated configuration;
• Citrix Desktop Director – provides the help desk with a single console to monitor,
troubleshoot and fix virtual desktops, not used in the evaluated configuration;
• Citrix XenMobile – a comprehensive solution to manage mobile devices, apps and data,
and allowing users to access all of their mobile, SaaS and Windows apps from a unified
corporate app store, not used in the evaluated configuration;
• Citrix AppDNA - reduces the time, cost and risk for OS migration and virtualization
technology adoptions by automating application compatibility and overall application
migration, not used in the evaluated configuration.
The following features of XenDesktop and XenApp are disallowed in the evaluated
configuration and are therefore not evaluated:
• Application delivery methods other than XenApp published apps, also known as server-
based hosted applications;
• Desktop delivery methods other than VDI desktops;
• Desktop delivery groups of the random type;
• The capability for users to belong to multiple desktop delivery groups;
• The capability for desktop users to be assigned multiple desktops in a desktop delivery
group;
• The capability for users to belong to multiple application delivery groups;
• Delegated administrator roles other than full administrators;
• Control of local peripheral support using individual and group policy (only global
policy is used);
• The ability for administrators to automatically create virtual desktops and servers using
Machine Creation Services;
• Power management of virtual machines via the Delivery Controller;
• The use of multiple Delivery Controllers;
• Connection leasing and use of Zones with Local Host Cache;
• Disconnected sessions;
• Non-brokered sessions;
• Streaming applications using AppV;
• The ability for administrators to deploy Personal vDisks for users and deliver
applications using AppV and AppDisks;
• The ability for users to access their personal office PC remotely from Citrix Receiver
using the Remote PC Access feature;
Version 1-0 Page 19 of 46
• The recording, archiving and playback of the on-screen activity of a user session hosted
on a Server or Desktop VDA using the Session Recording feature; and,
• Use of the Federated Authentication Service to support SAML-based logon to
StoreFront, and the use of unauthenticated (anonymous) delivery groups and StoreFront
stores.
Any VM Host used to provide virtual desktops or published applications is outside the scope
of the TOE (see OE.Config_VM_Host in section 4.2.1).
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2. CC Conformance
This ST supports the following conformance claims:
• CC Version 3.1 Revision 5,
• CC Part 2 conformant,
• CC Part 3 conformant, and,
• Evaluation Assurance Level (EAL) 2 augmented by ALC_FLR.2 Flaw Reporting
Procedures.
This ST does not claim conformance to any PPs.
Version 1-0 Page 21 of 46
3. Security Problem Definition
3.1 Assets
The assets to be protected by the TOE are as follows:
Desktop A virtual desktop. Protection requirements are for
confidentiality and integrity.
Published Applications The published applications made available by the TOE.
Protection requirements are for confidentiality and integrity.
Userdata User data in transit across a network between the User Device
and servers, and between servers. Protection requirements are
for confidentiality and integrity.
The following asset is introduced as a result of using the TOE:
Configdata Data generated by an administrator during configuration and
management of the TOE. This includes desktop users’ access
permissions for virtual desktops; virtual desktop configuration
data; lists of permitted published applications; and setup data
exchanged between server components and with the client
component during the establishment of a virtual desktop for
provision to a desktop user. Protection requirements are for
confidentiality and integrity.
3.2 Users and Subjects
The following define the users and IT systems. The subjects are interpreted as those
processes representing the defined users and external systems.
Application User A user who has been granted access to published applications
via the TOE. An Application User accesses virtual applications
through a client known as an Endpoint.
Desktop User A user who has been granted access to virtual desktops via the
TOE. The user accesses their virtual desktop through a client
known as an Endpoint.
Administrator An administrator manages users’ access to virtual desktops and
published applications. An administrator is responsible for the
configuration of the components of the TOE and the operational
environment, and is likely to have physical access to the TOE
server components.
Version 1-0 Page 22 of 46
Endpoint A client used to gain access to a virtual desktop or published
application. It consists of either a User Device running on a PC
or a virtual machine running a Desktop Virtual Delivery Agent.
To enable access, the Endpoint will be running the Client
component of the TOE.
3.3 Threats
3.3.1 Attacks on the TOE
The following items detail threats which the TOE (in some cases with the support of the
operational environment) is intended to address:
T.Attack_DesktopOrApp An attacker may gain unauthorised access to a virtual desktop
or published application.
T.Attack_Userdata An attacker may gain unauthorised access to Userdata.
T.Access_DesktopOrApp A desktop user or application user may gain unauthorised
access to a virtual desktop or published application (i.e. to a
virtual desktop that is not their own or to a published
application that they have not been given permission to access).
T.Access_Userdata A desktop user or application user may gain unauthorised
access to another user’s Userdata.
T.Intercept An attacker may intercept communication channels. This may
lead to compromise of users’ authentication credentials, other
Userdata, or Configdata in transit.
T.Spoof An attacker may cause communications between a User Device
and a server to be redirected, such that users of the TOE may
incorrectly believe they are accessing the TOE when they are
not. This may lead to compromise of Userdata or users’
authentication credentials.
T.Attack_Configdata An attacker, application user or desktop user may modify
Configdata.
3.4 Organisational Security Policies
P.Restrictions The TOE shall prevent the following actions by users when
configured to do so by an administrator in order to meet the
TOE customer’s security requirements:
• Cut and paste between a client clipboard and the
clipboard in a published application or virtual desktop;
Version 1-0 Page 23 of 46
• Client drive mapping in a published application or
virtual desktop; and,
• Access to User Device USB devices from virtual
desktops.
3.5 Assumptions
A.Physical It is assumed that TOE servers are installed in a physically
secure location that can only be accessed by authorised
administrators.
A.Config_Endpoint The Endpoint operating system is securely configured,
including appropriate file protection. In particular, a non-
administrative user should not have access to facilities to edit
the User Device registry.
A.Operations_Security Data (including keys) generated, processed, and stored outside
the TOE is managed in accordance with the level of risk. This
includes the application of appropriate controls to prevent the
use of cameras and smart phones to photograph screens, and
disabling screen capture and print screen functions on endpoints
if required by the TOE customer.
A.VM_Host The VM Host software provides virtual machine isolation and is
operating correctly and securely.
A.Third_Party_SW Trusted third-party software is operating correctly and securely.
This shall include administrators ensuring that applications are
published and configured such that it is not possible for users to
gain access to the underlying operating system or hardware on
which the Virtual Delivery Agent is running, other than in the
context of an unprivileged user account, or other applications.
The security state of the published applications should also be
maintained according to the user’s risk environment (e.g. by
applying relevant patches).
Version 1-0 Page 24 of 46
4. Security Objectives
4.1 Security Objectives for the TOE
O.Auth_User Users and administrators must be successfully identified and
authenticated before being granted access to the TOE.
O.Auth_Server TOE server components must authenticate themselves to User
Devices and other servers before communication of Userdata or
Configdata.
O.Desktop Each application user and desktop user must be granted access
only to the virtual desktop for which they have been authorised.
O.Application Each application user and desktop user must be granted access
only to applications for which they have been authorised.
O.Secure_Setup_Data The confidentiality and integrity of data required for setup and
assignment of a virtual desktop or published application must
be maintained during processing and transmission between
servers.
O.Secure_User_Data The confidentiality and integrity of Userdata being processed on
the virtual desktop or in a published application must be
maintained.
O.Config_Access The virtual desktops and published applications must only be
configurable by trusted administrators.
Application note Virtual Desktops and published applications must be configured
by administrators such that it is not possible for users to gain
access to the underlying operating system or hardware on which
the Virtual Delivery Agent is running, other than in the context
of an unprivileged user account.
O.Endpoint_Resource An administrator must be able to control the use of client-side
resources by authorised application and desktop users. This
includes the ability to cut, copy and paste information between
a client operating system clipboard and a published application
or virtual desktop; access, from a published application or
virtual desktop, to local drives on the client; access, from a
virtual desktop, to local USB devices on the User Device.
Version 1-0 Page 25 of 46
4.2 Security Objectives for the Environment
4.2.1 Security Objectives for the Technical Environment
The following technical objectives relate to the server components of the TOE:
OE.Config_Server The operating systems of the server components must be
securely configured according to [CCECG], including
appropriate file protection.
This includes ensuring that the contents of the memory used by
the Virtual Delivery Agent to run the virtual desktop during a
user’s session are not available to other processes when that
user’s session has ended (this is achieved in the evaluated
configuration by maintaining the assignment between each
virtual desktop and its user, so that the user is always connected
to the same persistent desktop).
OE.Config_VM_Host VM Host software must be securely configured. The
deployment must provision a VM Host that provides suitable
virtual machine isolation since this is relied upon to effect
separation of user's virtual desktops in the XenDesktop security
architecture. The VM Host should therefore be a hypervisor
certified against a security target that includes the separation of
virtual machines (including virtual memory, virtual disk and
networking).
OE.Config_TP_SW Trusted third-party software must be securely configured
according to [CCECG].
Published applications must be configured by administrators
such that it is not possible for users to gain access to the
underlying operating system or hardware on which the Virtual
Delivery Agent is running, other than in the context of an
unprivileged user account, or other applications.
OE.Authenticate Users and administrators must be authenticated by the
underlying operating system on the relevant platform.
Authentication requirements in the operating system shall be
configured according to the risks in the operational
environment. This includes authentication using the domain
controller in the environment and any two-factor authentication
used by the TOE customer such as smart cards.
OE.TLS All communication between the TOE Servers, between Virtual
Delivery Agents and User Device Citrix Receivers, and
between StoreFront and the User Device (web browser), uses
the configured TLS protocol. This is provided by the Windows
operating system cryptograhic modules.
Version 1-0 Page 26 of 46
OE.Encryption Communications between the DDC and VDA are not protected
by TLS, but by WCF message-level security. This is provided
by the Windows operating system cryptographic module. It uses
XML-based WS-Security mechanisms to provide HMAC and
encryption for the message contents together with Kerberos-
based authentication.
The following technical objectives relate to the User Devices:
OE.Config_Endpoint The Endpoint operating system must be securely configured
according to [CCECG], including appropriate file protection
and other security best practices.
Application note Endpoints must be configured such that user authentication
credentials and user data are not available after the user has
logged out from their virtual desktop. Users should also log out
of their Windows session on the User Device after logging out
from their virtual desktop. If required, endpoint functionality
such as screen capture and screen print must be disabled so that
users can not bypass controls on data movement between
published desktops/applications and their local endpoint.
The following technical objectives relate to connectivity between components of the TOE:
OE.Operations_Security Any keys and other secret data that are generated and stored
outside the TOE must be managed in accordance with the level
of risk.
4.2.2 Security Objectives for the Procedural Environment
OE.Server_Physical The operational environment shall provide physical protection
to the TOE servers to ensure only administrators are able to
gain physical access to the servers.
OE.Endpoint_TP_SW Endpoints must have only trusted third-party software installed.
This software must be configured securely according to the
risks in the operational environment.
OE.Admin_Users Configdata stored outside the TOE, such as in the database,
must be accessible only by administrators.
Version 1-0 Page 27 of 46
4.3 SPD/Objectives Rationale
The following table provides a summary of the relationship between the security objectives
and the security problem definition. The rationale is provided in the sections that follow.
Threat/
OSP/
Assumption
T.Attack_DesktopOrApp
T.Attack_Userdata
T.Access_DesktopOrApp
T.Access_Userdata
T.Intercept
T.Spoof
T.Attack_Configdata
P.Restrictions
A.Physical
A.Config_Endpoint
A.Operations_Security
A.VM_Host
A.Third_Party_SW
Security Objectives
O.Auth_User X X X
O.Auth_Server X X
O.Desktop X X
O.Application X X
O.Secure_Setup_Data X X X
O.Secure_User_Data X X
O.Config_Access X X X X
O.Endpoint_Resource X X
OE.Config_Server X X X X X X
OE.Config_VM_Host X X X X X X
OE.Config_TP_SW X X X X X X X
OE.Authenticate X X X X
OE.TLS X X X X X
OE.Config_Endpoint X X X X X X
OE.Encryption X X X X
OE.Operations_Security X
OE.Server_Physical X
OE.Endpoint_TP_SW X X
OE.Admin_Users X X
Table 1: Threats/OSP/Assumptions addressed by Security Objectives
Version 1-0 Page 28 of 46
4.3.1 T.Attack_DesktopOrApp
Attackers are prevented from gaining access to a virtual desktop or published application by a
combination of TOE and environment objectives to apply identification and authentication.
O.Auth_User and OE.Authenticate ensure that only identified and authenticated desktop
users, application users and administrators are granted access to the TOE.
OE.Config_Server ensures that the servers have been set up properly, while
OE.Config_VM_Host and OE.Config_TP_SW ensure that potentially privileged programs do
not undermine security.
OE.Config_Endpoint ensures that the Endpoints have been set up properly and that
authentication credentials are not left in the Endpoint memory to be retrieved by an attacker.
4.3.2 T.Attack_Userdata
Attackers are prevented from gaining access to Userdata by a combination of TOE and
environment objectives to apply authentication, authorisation, confidentiality and integrity.
O.Auth_User and OE.Authenticate ensure that only identified and authenticated desktop
users, application users and administrators are granted access to the TOE.
OE.TLS and OE.Encryption ensure the confidentiality of Userdata, including authentication
credentials, during login and establishment of a virtual desktop and published application
session.
O.Secure_User_Data ensures the confidentiality and integrity of Userdata being processed on
a virtual desktop or published application.
O.Config_Access ensures that the virtual desktops and published applications have been set
up properly, while OE.Config_Server ensures that any content of the virtual desktop memory
is reserved for that user after the user has logged out of the virtual desktop.
OE.Config_Server also ensures that the servers have been set up properly, while
OE.Config_VM_Host and OE.Config_TP_SW ensure that potentially privileged programs do
not undermine security.
OE.Config_Endpoint ensures that the Endpoints have been set up properly and that
authentication credentials and other Userdata are not left in the Endpoint memory to be
retrieved by an attacker.
4.3.3 T.Access_DesktopOrApp
Users are prevented from gaining unauthorised access to a virtual desktop or published
application by a combination of TOE and environment objectives to apply authorisation,
confidentiality and integrity.
Version 1-0 Page 29 of 46
O.Desktop ensures that a virtual desktop is only available to an desktop user who has been
specifially authorised for access to the relevant desktop. O.Application similarly ensures that
a published application is only available to an application user who has been specifically
authorised for access to the relevant application (as recorded in the Configdata).
OE.Admin_Users ensures that only administrators have access to Configdata and thus the
ability to authorise users’ access to a virtual desktop or published application.
O.Secure_Setup_Data ensures the confidentiality and integrity of the setup and assignment
data for virtual desktops and published applications on the servers.
O.Config_Access ensures that the virtual desktops and published applications have been set
up properly.
OE.Config_Server also ensures that the servers have been set up properly, while
OE.Config_VM_Host and OE.Config_TP_SW ensure that potentially privileged programs do
not undermine security.
4.3.4 T.Access_Userdata
Desktop users and application users are prevented from gaining unauthorised access to
another user’s Userdata by a combination of TOE and environment objectives to apply
authentication, authorisation, confidentiality and integrity.
O.Desktop ensures that a virtual desktop is only available to a desktop user authorised to
have access. O.Application similarly ensures that a published application is only available to
an application user who has been specifically authorised for access to the relevant application
(as recorded in the Configdata). OE.Authenticate ensures that the underlying operating
system performs the required authenticaiton on which to base access decisions.
OE.TLS and OE.Encryption ensure the confidentiality of Userdata, including authentication
credentials, during login and establishment of a virtual desktop or access to a published
application.
O.Secure_User_Data, ensures the confidentiality and integrity of Userdata being processed
on a virtual desktop or in a published application.
O.Config_Access ensures that the virtual desktops and published applications have been set
up properly, while OE.Config_Server ensures that any content of the virtual desktop memory
is reserved for that user after the user has logged out of the virtual desktop.
OE.Config_Server also ensures that the servers have been set up properly, while
OE.Config_VM_Host and OE.Config_TP_SW ensure that potentially privileged programs do
not undermine security.
O.Endpoint_Resource ensures that users can only use the clipboard and devices attached to
the Endpoint when authorised.
OE.Config_Endpoint ensures that the Endpoints have been set up properly and that
authentication credentials and other Userdata are not available to be used by an attacker.
Version 1-0 Page 30 of 46
4.3.5 T.Intercept
Attackers are prevented from intercepting communications channels by a combination of
TOE and environment objectives to apply authentication, confidentiality and integrity.
O.Auth_Server ensures that servers authenticate themselves to clients and other servers
before communicating Userdata or Configdata. O.Secure_Setup_Data ensures the
confidentiality and integrity of the setup and assignment data for the virtual desktop and
published applications during transmission between servers.
OE.TLS and OE.Encryption ensure the confidentiality and integrity of communications
between the User Device browser and StoreFront during login and establishment of the
virtual desktop or access to a published application, and also ensures the confidentiality and
integrity of communications between the User Device and the virtual desktop.
4.3.6 T.Spoof
Attackers are prevented from redirecting communications between a User Device and a
server to a spoof server by a combination of TOE and environment objectives to apply
authentication, confidentiality and integrity.
O.Auth_Server and OE.TLS ensure that servers authenticate themselves to clients before
communicating Userdata such as authentication credentials.
OE.Config_Server ensures that the servers have been set up properly, while
OE.Config_VM_Host and OE.Config_TP_SW ensure that potentially privileged programs do
not undermine security.
OE.Config_Endpoint and OE.Endpoint_TP_SW ensure that the Endpoints have been set up
properly.
4.3.7 T.Attack_Configdata
Attackers, application users and desktop users are prevented from modifying Configdata by a
combination of TOE and environment objectives to apply authentication, authorisation,
confidentiality and integrity.
O.Auth_User and OE.Authenticate ensure that only identified and authenticated desktop
users, application users and administrators are granted access to the TOE.
OE.Admin_Users ensures that only administrators have access to Configdata.
O.Secure_Setup_Data, OE.TLS and OE.Encryption ensure the confidentiality and integrity of
the Configdata on the servers and when transmitted between servers.
OE.Config_Server ensures that the servers have been set up properly, while
OE.Config_TP_SW ensures that potentially privileged programs do not undermine security.
Version 1-0 Page 31 of 46
4.3.8 P.Restrictions
Restrictions are in place to control whether TOE facilitates moving data between published
applications and virtual desktops and the user’s endpoint.
O.Endpoint_Resource ensures that users can only use the clipboard and devices attached to
the Endpoint when authorised. This controls cut and paste and moving files between the
published desktop or application and the endpoint.
O.Config_Access ensures that the virtual desktops and published applications have been set
up properly.
OE.Config_Endpoint ensures that the security of TOE will not be compromised by the
security of the endpoint.
4.3.9 A.Physical
The assumption that TOE servers are installed in physically secure locations is addressed by
the environment objective OE.Server_Physical which ensures that servers are physically
protected and only accessible by administrators.
4.3.10 A.Config_Endpoint
The assumption that User Device operating systems are securely configured with appropriate
access permissions is met by the environment objective OE.Config_Endpoint which ensures
that the Endpoint is securely configured including the file protection.
4.3.11 A.Operations_Security
The assumption that secret data outside the TOE is managed appropriately, is met by
environment objective OE.Operations_Security which ensures that keys and other secret data
generated and stored outside the TOE are managed in accordance with the level of risk.
4.3.12 A.VM_Host
The assumption that VM Host software is operating correctly and securely, and uses a
hypervisor to provide VM separation, is met by the environment objective
OE.Config_VM_Host, which ensures that these requirements are met.
4.3.13 A.Third_Party_SW
The assumption that third-party software is operating correctly and securely is met by the
environment objectives OE.Config_TP_SW which ensures that trusted third-party software is
securely configured, and OE.Endpoint_TP_SW which ensures that only securely configured
trusted third-party software is installed on the User Devices.
Version 1-0 Page 32 of 46
5. IT Security Requirements
5.1 Conventions
The following conventions are used for the completion of operations:
• Strikethrough indicates text removed as a refinement and underlined text indicates
additional text provided as a refinement.
• [Bold text within square brackets] indicates the completion of an assignment.
• [Italicised text within square brackets] indicates the completion of a selection.
5.2 Security Functional Requirements
The operation of the TOE is considered under four functional groupings for the purposes of
the specification of the security functional requirements. These are:
• Authentication
• Authorisation
• Communications
The individual security functional requirements are specified in the sections below. Unless
stated otherwise, the term ‘user’ should be understood to relate to desktop users, published
application users and administrators.
5.2.1 Authentication
The SFRs in this section are concerned with enforcing access control to ensure that only
authenticated users are granted access to the TOE and virtual desktops/published
applications.
5.2.1.1 FIA_ATD.1/User User attribute definition
FIA_ATD.1.1/User The TSF shall maintain the following list of security attributes
belonging to individual users: [id, group membership].
5.2.1.2 FIA_UID.2/User User identification before any action
FIA_UID.2.1/User The TSF shall require each user to be successfully identified
before allowing any other TSF-mediated actions on behalf of
that user.
Application note The user identification requirement applies to administrators, as
well as to application users and desktop users.
Version 1-0 Page 33 of 46
5.2.2 Authorisation
The SFRs in this section are concerned with providing the administrator with the means to
authorise desktop users for access to virtual desktops and application users for access to
published applications, and to limit the operations that the desktop users are able to perform.
5.2.2.1 FMT_SMR.1/Authorise Security management roles
FMT_SMR.1.1/Authorise The TSF shall maintain the roles [desktop user, application
user, administrator].
FMT_SMR.1.2/Authorise The TSF shall be able to associate users with roles.
5.2.2.2 FMT_SMF.1/Authorise Specification of management functions
FMT_SMF.1.1/Authorise The TSF shall be capable of performing the following
management functions: [
• Definition of published applications
• Administration of access permissions for published
applications
• Allocation of administrator role to users
• Administration of access permissions for virtual
desktops
• Administration of virtual desktop configuration data
• Administration of Endpoint data access control policy.]
Application note Adminstration of virtual desktop configuration data includes
assigning each desktop machine to a single desktop user.
Administration of the Endpoint data access control policy
consists of enabling or disabling the following functions for
published applications and virtual desktops:
• cut and paste between a client clipboard and the clipboard in
a published application or virtual desktop;
• client drive mapping in a published application or virtual
desktop;
• access to User Device USB devices from virtual desktops.
Version 1-0 Page 34 of 46
5.2.2.3 FDP_ACC.1/Application Subset access control
FDP_ACC.1.1/Application The TSF shall enforce the [Application Access Policy] on
[application users attempting access to a published
application].
5.2.2.4 FDP_ACF.1/Application Security attribute based access control
FDP_ACF.1.1/Application The TSF shall enforce the [Application Access Policy] to
objects based on the following: [
subject (user) security attribute: id, group membership
object (application) security attributes: security
permissions].
FDP_ACF.1.2/Application The TSF shall enforce the following rules to determine if an
operation among controlled subjects and controlled objects is
allowed: [An application shall be accessible by a user only if
security permissions for the delivery group to which the
application is assigned explicitly grant the user id or the
user group the access required.]
FDP_ACF.1.3/Application The TSF shall explicitly authorise access of subjects to objects
based on the following additional rules: [None].
FDP_ACF.1.4/Application The TSF shall explicitly deny access of subjects to objects
based on the following additional rules: [None].
5.2.2.5 FMT_MSA.1/Application Management of Security Attributes
FMT_MSA.1.1/Application The TSF shall enforce the [Application Access Policy] to
restrict the ability to [modify] the security attributes: [
a) User id
b) User group,
c) Security permissions]
to [administrators].
Version 1-0 Page 35 of 46
5.2.2.6 FMT_MSA.3/Application Static attribute initialisation
FMT_MSA.3.1/Application The TSF shall enforce the [Application Access Policy] to
provide [restrictive] default values for security attributes that
are used to enforce the SFP.
Application note Administrators are instructed by [CCECG] to always select the
correct options to establish a restrictive configuration.
FMT_MSA.3.2/Application The TSF shall allow the [administrator] to specify alternative
initial values to override the default values when an object or
information is created.
5.2.2.7 FDP_ACC.1/Desktop Subset access control
FDP_ACC.1.1/Desktop The TSF shall enforce the [Desktop access policy] on [desktop
users’ access to virtual desktops].
5.2.2.8 FDP_ACF.1/Desktop Security attribute based access control
FDP_ACF.1.1/Desktop The TSF shall enforce the [Desktop Access Policy] to objects
based on the following: [
subject (user) security attribute: id
object (desktop) security attribute: security permissions].
FDP_ACF.1.2/Desktop The TSF shall enforce the following rules to determine if an
operation among controlled subjects and objects is allowed:
[Security permissions explicitly grant the user id the access
required.]
FDP_ACF.1.3/Desktop The TSF shall explicitly authorise access of subjects to objects
based on the following additional rules: [none].
FDP_ACF.1.4/Desktop The TSF shall explicitly deny access of subjects to objects
based on the following additional rules: [none].
5.2.2.9 FMT_MSA.1/Desktop Management of security attributes
FMT_MSA.1.1/Desktop The TSF shall enforce the [Desktop access policy] to restrict
the ability to [modify] the security attributes: [
• User id
• Security permissions]
to [administrators].
Version 1-0 Page 36 of 46
5.2.2.10 FMT_MSA.3/Desktop Static attribute initialisation
FMT_MSA.3.1/Desktop The TSF shall enforce the [Desktop access policy] to provide
[restrictive] default values for security attributes that are used to
enforce the policy.
Application note Administrators are instructed by [CCECG] to always select the
correct options to establish a restrictive configuration.
FMT_MSA.3.2/Desktop The TSF shall allow the [administrator] to specify alternative
initial values to override the default values when an object or
information is created.
Application note The administrator is required (see [CCECG]) to set the virtual
desktop configuration data to assign each virtual desktop to a
single user.
5.2.2.11 FDP_ACC.1/Resources Subset access control
FDP_ACC.1.1/Resources The TSF shall enforce the [Resource access policy] on [use by
application users and desktop users of the following
operations
• transfer of user data between the endpoint clipboard and
a published application or virtual desktop clipboard;
• access to mapped client drives from a published
application or virtual desktop; and,
• access to endpoint-attached USB devices from a virtual
desktop].
Application note A USB storage device may be accessed through client drive
mapping or through general USB device access (subject to
configuration). General USB device access is available from
virtual desktops but not from within published applications.
Hence within a published application a USB storage device can
only be made available using client drive mapping: there is no
general USB device access available from within published
applications.
5.2.2.12 FDP_ACF.1/Resources Security attribute based access control
FDP_ACF.1.1/Resources The TSF shall enforce the [Resource access policy] to objects
based on the following: [
subject (user) security attribute: none
Version 1-0 Page 37 of 46
object (application or virtual desktop) security attribute:
endpoint data access permissions].
FDP_ACF.1.2/Resources The TSF shall enforce the following rules to determine if an
operation among controlled subjects and objects is allowed: [
1) Users shall be permitted to cut and paste data between a
published application or a virtual desktop and an
endpoint operating system clipboard if the cut and paste
function is enabled in the endpoint data access
permissions.
2) Endpoint drives shall be accessible to a published
application or a virtual desktop only if the client drive
mapping function is enabled in the endpoint data access
permissions.
3) USB devices on an endpoint shall be accessible to a
virtual desktop only if the USB device access function is
enabled in the endpiont data access permissions.]
Application note Note that that endpoint data access permissions allowed in the
evaluated configuration are global and therefore apply to all
users. Individual and group permissions are disallowed in the
evaluated configuration.
FDP_ACF.1.3/Resources The TSF shall explicitly authorise access of subjects to objects
based on the following additional rules: [none].
FDP_ACF.1.4/Resources The TSF shall explicitly deny access of subjects to objects
based on the following additional rules: [none].
5.2.2.13 FMT_MSA.1/Resources Management of security attributes
FMT_MSA.1.1/Desktop The TSF shall enforce the [Resource access policy] to restrict
the ability to [modify] the security attributes: [
• endpoint data access permissions]
to [administrators].
5.2.2.14 FMT_MSA.3/Resources Static attribute initialisation
FMT_MSA.3.1/Resources The TSF shall enforce the [Resource access policy] to provide
[restrictive] default values for security attributes that are used to
enforce the policy.
Application note The default values are restrictive in that, although the defaults
may be configured differently during installation, the cut and
paste, client drive mapping and USB device access functions
Version 1-0 Page 38 of 46
will default to disabled following installation of the evaluation
configuration.
FMT_MSA.3.2/Resources The TSF shall allow the [administrator] to specify alternative
initial values to override the default values when an object or
information is created.
5.2.3 Communications
The SFR in this section is concerned with protecting data that is being communicated
between separate components of the TOE.
5.2.3.1 FPT_ITT.1 Basic Internal TSF Data Transfer Protection
FPT_ITT.1.1 The TSF shall protect TSF data from [disclosure and
modification] when it is transmitted between separate parts of
the TOE.
5.3 Security Assurance Requirements
The security assurance requirements are drawn from [CC3] and represent EAL2, with the
addition of ALC_FLR.2 Flaw Reporting Procedures. The assurance components are
identified in the table below.
Assurance Class Assurance Components
Development (ADV) Security architecture description (ADV_ARC.1)
Security-enforcing functional specification (ADV_FSP.2)
Basic design (ADV_TDS.1)
Guidance documents (AGD) Operational user guidance (AGD_OPE.1)
Preparative procedures (AGD_PRE.1)
Life cycle support (ALC) Use of a CM System (ALC_CMC.2)
Parts of the TOE CM coverage (ALC_CMS.2)
Delivery procedures (ALC_DEL.1)
Flaw reporting procedures (ALC_FLR.2)
Tests (ATE) Evidence of coverage (ATE_COV.1)
Functional testing (ATE_FUN.1)
Independent testing – sample (ATE_IND.2)
Vulnerability assessment (AVA) Vulnerability analysis (AVA_VAN.2)
Table 2: Security Assurance Requirements
The selection of EAL2 is consistent with the assurance levels commonly used for commercial
products of this sort, and the augmentation with ALC_FLR.2 provides additional confidence
for users that there is a process for reporting and addressing any vulnerabilities that might be
Version 1-0 Page 39 of 46
subsequently discovered in the product, and hence that its security will be maintained over
time.
Version 1-0 Page 40 of 46
5.4 Objectives/SFRs Rationale
The following table provides a summary of the relationship between the security objectives
and the security functional requirements. The rationale is in the sections that follow.
SFRs FIA_ATD.1/User
FIA_UID.2/User
FMT_SMR.1/Authorise
FMT_SMF.1/Authorise
FDP_ACC.1/Desktop
FDP_ACF.1/Desktop
FMT_MSA.1/Desktop
FMT_MSA.3/Desktop
FDP_ACC.1/Resources
FDP_ACF.1/Resources
FDP_ACC.1/Application
FDP_ACF.1/Application
FMT_MSA.1/Application
FMT_MSA.3/Application
FMT_MSA.1/Resources
FMT_MSA.3/Resources
FPT_ITT.1
Security Objectives
O.Auth_User X
O.Auth_Server X
O.Desktop X X X X X X X
O.Application X X X X X X X
O.Secure_Setup_Data X X X X X X X
O.Secure_User_Data X
O.Config_Access X X X X X X X X X X X X
O.Endpoint_Resource X X X X X X
Table 3: Summary of Objectives/SFRs Rationale
5.4.1 O.Auth_User
This objective is addressed by FIA_UID.2/User which ensures that desktop users and
administrators are successfully identified and authenticated before they can use the TOE
functionality. (Authentication is provided in the OE by a domain controller.)
5.4.2 O.Auth_Server
This objective is addressed by FPT_ITT.1. This ensures the confidentiality, integrity and
authenticity of TOE components for all communications between TOE servers, and between
User Devices and TOE servers.
5.4.3 O.Desktop
This objective is addressed by FIA_ATD.1/User, in conjunction with the security
management functions (FMT_SMR.1/Authorise, FMT_SMF.1/Authorise,
FMT_MSA.1/Desktop, FMT_MSA.3/Desktop) and the Desktop access policy
(FDP_ACC.1/Desktop, FDP_ACF.1/Desktop).
Version 1-0 Page 41 of 46
FIA_ATD.1/User ensures that individual desktop users can be granted access permissions for
virtual desktops, while FMT_SMR.1/Authorise, FMT_SMF.1/Authorise,
FMT_MSA.1/Desktop and FMT_MSA.3/Desktop ensure that only administrators can
manage the desktop users’ access permissions.
The Desktop access policy (FDP_ACC.1/Desktop and FDP_ACF.1/Desktop) ensures that
only desktop users with the correct access permissions can gain access to a virtual desktop.
5.4.4 O.Application
This objective is addressed by FIA_ATD.1/User, in conjunction with the security
management functions (FMT_SMR.1/Authorise, FMT_SMF.1/Authorise,
FMT_MSA.1/Application, FMT_MSA.3/Application) and the application access policy
(FDP_ACC.1/Application, FDP_ACF.1/Application).
FIA_ATD.1/User ensures that application users can be granted access permissions for
published applications, while FMT_SMR.1/Authorise, FMT_SMF.1/Authorise,
FMT_MSA.1/Application and FMT_MSA.3/Application ensure that only administrators can
manage the application users’ access permissions.
The application access policy (FDP_ACC.1/Application and FDP_ACF.1/Application)
ensures that only application users with the correct access permissions can gain access to a
published application.
5.4.5 O.Secure_Setup_Data
This objective is addressed by FPT_ITT.1 in conjunction with the security management
functions (FMT_SMR.1/Authorise, FMT_SMF.1/Authorise, FMT_MSA.1/Desktop,
FMT_MSA.3/Desktop, FMT_MSA.1/Application, FMT_MSA.3/Application).
FPT_ITT.1 ensures the confidentiality and integrity of communications between separate
TOE servers to protect Configdata, while FMT_SMR.1/Authorise, FMT_SMF.1/Authorise,
FMT_MSA.1/Desktop, FMT_MSA.3/Desktop, FMT_MSA.1/Application, and
FMT_MSA.3/Application ensure that only administrators can manage Configdata.
5.4.6 O.Secure_User_Data
This objective is addressed by FPT_ITT.1 which ensures the confidentiality and integrity of
communications between Citrix Receiver and the Virtual Delivery Agent, and the
confidentiality and integrity of communications between TOE servers.
5.4.7 O.Config_Access
This objective is addressed by the security management functions (FMT_SMR.1/Authorise,
FMT_SMF.1/Authorise, FMT_MSA.1/Desktop, FMT_MSA.3/Desktop
(FMT_MSA.1/Application, FMT_MSA.3/Application), the Desktop access policy
(FDP_ACC.1/Desktop, FDP_ACF.1/Desktop), the Application access policy
(FDP_ACC.1/Application, FDP_ACF.1/Application), and the Resource access policy
(FMT_MSA.1/Resources, FMT_MSA.3/Resources).
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FMT_SMR.1/Authorise, FMT_SMF.1/Authorise, FMT_MSA.1/Desktop,
FMT_MSA.3/Desktop, FMT_MSA.1/Application, FMT_MSA.3/Application,
FMT_MSA.1/Resources, and FMT_MSA.3/Resources ensure that only administrators can
modify or delete virtual desktop and published application configuration data.
5.4.8 O.Endpoint_Resource
This objective is addressed by security management functions (FMT_SMR.1/Authorise,
FMT_SMF.1/Authorise, FMT_MSA.1/Resources, FMT_MSA.1/Resources, and
FMT_MSA.3/Resources) and the Resource access policy (FDP_ACC.1/Resources,
FDP_ACF.1/Resources).
FMT_SMR.1/Authorise, FMT_SMF.1/Authorise, and FMT_MSA.3/Resources ensure that
only authorised administrators can enable or disable cut and paste, client drive mapping, and
USB device access functions.
The Resource access policy (FDP_ACC.1/Resources and FDP_ACF.1/Resources) ensures
that desktop users can only cut and paste data between a virtual desktop and the User Device
operating system clipboard if the cut and paste function has been enabled by an administrator.
The Resource access policy (FDP_ACC.1/Resources and FDP_ACF.1/Resources) ensures
that desktop users can only access User Device client drives from the virtual desktop if the
client drive mapping function has been enabled by an administrator and the user has
permitted the access.
The Resource access policy (FDP_ACC.1/Resources and FDP_ACF.1/Resources) ensures
that desktop users can only access USB devices on a User Device from the virtual desktop if
the USB device access function has been enabled by an administrator and the user has
permitted the access.
5.5 SFR Dependencies Analysis
The dependencies between SFRs implemented by the TOE are detailed in the table below.
SFR Dependencies Rationale
FIA_ATD.1/User None
FIA_UID.2/User None
FMT_SMR.1/Authorise FIA_UID.1 Met by FIA_UID.2/User
FMT_SMF.1/Authorise None
FDP_ACC.1/Desktop FDP_ACF.1 Met by FDP_ACF.1/Desktop
FDP_ACF.1/Desktop FDP_ACC.1 Met by FDP_ACC.1/Desktop
FMT_MSA.3 Met by FMT_MSA.3/Desktop
FMT_MSA.1/Desktop FDP_ACC.1 or FDP_IFC.1 Met by FDP_ACC.1/Desktop
FMT_SMR.1 Met by FMT_SMR.1/Authorise
FMT_MSA.3/Desktop FMT_MSA.1 Met by FMT_MSA.1/Desktop
Version 1-0 Page 43 of 46
SFR Dependencies Rationale
FMT_SMR.1 Met by FMT_SMR.1/Authorise
FMT_SMF.1 Met by FMT_SMF.1/Authorise
FDP_ACC.1/Application FDP_ACF.1 Met by FDP_ACF.1/Application
FDP_ACF.1/Application FDP_ACC.1 Met by FDP_ACC.1/Application
FMT_MSA.3 Met by FMT_MSA.3/Application
FMT_MSA.1/Application FDP_ACC.1 or FDP_IFC.1 Met by FDP_ACC.1/Application
FMT_SMR.1 Met by FMT_SMR.1/Authorise
FMT_MSA.3/Application FMT_MSA.1 Met by FMT_MSA.1/Application
FMT_SMR.1 Met by FMT_SMR.1/Authorise
FMT_SMF.1 Met by FMT_SMF.1/Authorise
FDP_ACC.1/Resources FDP_ACF.1 Met by FDP_ACF.1/Resources
FDP_ACF.1/Resources FDP_ACC.1 Met by FDP_ACC.1/Resources
FMT_MSA.3 Met by FMT_MSA.3/ Resources
FMT_MSA.3/Resources FMT_MSA.1 Met by FMT_MSA.1/Resources
FMT_SMR.1 Met by FMT_SMR.1/Authorise
FMT_SMF.1 Met by FMT_SMF.1/Authorise
FPT_ITT.1 None
Table 4: Analysis of SFR Dependencies
Version 1-0 Page 44 of 46
6. TOE Summary Specification
The table below provides a summary of the TOE functions that satisfy the security functional
requirements described in section 5.2 above. The following sections describe how the TOE
functions satisfy the security functional requirements.
SFRs
FIA_ATD.1/User
FIA_UID.2/User
FMT_SMR.1/Authorise
FMT_SMF.1/Authorise
FDP_ACC.1/Desktop
FDP_ACF.1/Desktop
FMT_MSA.1/Desktop
FMT_MSA.3/Desktop
FDP_ACC.1/Resources
FDP_ACF.1/Resources
FDP_ACC.1/Application
FDP_ACF.1/Application
FMT_MSA.1/Application
FMT_MSA.3/Application
FMT_MSA.1/Resources
FMT_MSA.3/Resources
FPT_ITT.1
TOE Functions
Administrator
access control
X
Administration of
virtual desktop and
published application
authorisation
X X X X X X X X X
Desktop user and
Application user
access control
X X X X X
User Device resource
access control
X X
Secure
communications
X
Table 5: Summary of SFRs satisfied by TOE Functions
6.1 Administrator access control
Administrators are authenticated as part of their Windows login via the operating system and
domain controller (see OE.Authentication). The authenticated identity is used by the Delivery
Controller for authorisation before access is provided for administrators to Configdata.
These administrator access control mechanisms satisfy the FIA_UID.2/User requirement for
administrators.
6.2 Administration of virtual desktop and published application
authorisation
The management of Configdata is performed by an administrator using Citrix Studio, in
conjunction with the Delivery Controller which controls access, and the database wherein the
Configdata is stored.
Version 1-0 Page 45 of 46
Only administrators are able to modify Configdata. Configdata includes:
• Access permissions for administrators, determining whether administrative users can
access configdata;
• Access permissions for virtual desktops, determining which virtual desktops each user
can access;
• The list of published applications and access permissions for users to those applications
(i.e. the list of permitted published applications);
• Virtual Desktop configuration data, determining the configuration and characteristics of
each virtual desktop;
• Endpoint data access policy, defining a central control policy that determines whether
or not the user of a virtual desktop can cut and paste data between virtual desktop and
User Device clipboards, whether the user is permitted to access local drives from the
virtual desktop, and whether the user is permitted to access User Device USB devices
from the virtual desktop.
These administration mechanisms satisfy the FMT_SMR.1/Authorise,
FMT_SMF.1/Authorise, FMT_MSA.1/Desktop, FMT_MSA.1/Application,
FMT_MSA.3/Desktop, FMT_MSA.3/Application, FMT_MSA.1/Resources, and
FMT_MSA.3/Resources security management requirements as well as the
FIA_ATD.1/User attribute requirement.
6.3 Desktop user and Application user access control
StoreFront provides the means for a user to log in to the TOE using a web browser or Citrix
Receiver, in order to gain access to their virtual desktops and permitted published
applications. StoreFront receives the user’s credentials, which may be username/password or
multifactor authentication using a smart card. It forwards the credentials to the Delivery
Controller for authentication by the domain controller. Users must be registered with the
domain controller and are identified and authenticated as part of their Windows login.
The authenticated identity is used by the Delivery Controller for authorisation to ensure that
users are only granted access to virtual desktops and published applications for which they
have the appropriate permission. Once a user’s access permission has been verified, the
Delivery Controller assembles the user’s virtual desktop or published application
environment using the virtual desktop configuration data or access permissions for published
applications. The Delivery Controller starts the virtual desktop and generates a ticket which
is passed to the Virtual Delivery Agent and, via StoreFront, to the user’s Citrix Receiver.
The Citrix Receiver in the user’s User Device uses the ticket to establish a session with the
appropriate Virtual Delivery Agent. The Virtual Delivery Agent provides access to the
virtual desktop and permitted published applications for the user. It authenticates the user
before establishing the session, by confirming that the same ticket has been presented by the
Citrix Receiver as that supplied by the Delivery Controller. (See also section 1.3 for
additional description of the steps, interactions and data items involved.)
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Once a user has logged out of a virtual desktop, the virtual desktop and its virtual machine
are preserved and available only for that user.
These user access control mechanisms satisfy the FIA_UID.2/User requirement for users, as
well as the desktop and published application access policy requirements
(FDP_ACC.1/Desktop, FDP_ACF.1/Desktop, FDP_ACC.1/Application and
FDP_ACF.1/Application).
6.4 User Device resource access control
Desktop users and application users can use User Device resources if an administrator has
enabled the appropriate functions in the Endpoint data access control policy. This is enforced
by the Citrix Receiver and the Virtual Delivery Agent. Only global enabling of the functions
(i.e. applicable to the entire Site) is included in the scope of the evaluation.
The User Device resource access control mechanisms satisfy the resource access policy
requirements (FDP_ACC.1/Resources and FDP_ACF.1/Resources).
6.5 Secure communications
Communication between StoreFront and the User Device web browser is protected by TLS.
Communication between the Virtual Delivery Agent and the Citrix Receiver in the user’s
User Device is protected by Windows secure communications mechanisms, which are
configured to use TLS for authentication, confidentiality and integrity.
Communication between the TOE servers is protected by Windows secure communications
mechanisms, which are configured to use either TLS or Windows message-level security (as
shown in Figure 1) for authentication, confidentiality and integrity.
The TOE ensures that communications are protected by leveraging two Windows
cryptographic modules in the environment. Server-side components of communication
channels leverage the kernel mode cryptographic module. Client applications, including the
web browser, use the user-mode DLL module.
These secure communications mechanisms satisfy the FPT_ITT.1 requirements for integrity-
protected and encrypted communication channels.
***End of Document***