PP-Module for Virtual Private Network (VPN) Clients
Version: 2.4 2022-03-31 National Information Assurance Partnership
Foreword
This is a Supporting Document (SD), intended to complement the Common Criteria version 3
and the associated Common Evaluation Methodology for
Information Technology Security Evaluation.
SDs may be “Guidance Documents”, that highlight specific approaches
and application of the standard to areas where no mutual recognition of
its application is required, and as such, are not of normative nature,
or “Mandatory Technical Documents”, whose application is mandatory for evaluations
whose scope is covered by that of the SD.
The usage of the latter class is not only mandatory, but certificates
issued as a result of their application are recognized under the CCRA.
Technical Editor:
National Information Assurance Partnership (NIAP)
Document history:
Version
Date
Comment
2.4
2022-03-31
Incorporation of TC feedback
2.3
2021-08-10
Support for MDF, Bluetooth updates
2.2
2021-01-05
Update release
2.1
2019-11-14
Initial Release
General Purpose:
The purpose of this SD is to define evaluation methods for the functional behavior of
Virtual Private Network (VPN) Clients products.
Acknowledgments:
This SD was developed with support from NIAP
Virtual Private Network (VPN) Clients Technical Community members, with representatives from industry, government
agencies, Common Criteria Test Laboratories, and members of academia.
1.1 Technology Area and Scope of Supporting Document
The scope of the
PP-Module for Virtual Private Network (VPN) Clients is
to describe the security functionality of
Virtual Private Network (VPN) Clients products in terms of
[CC] and to define functional and assurance requirements for them.
The PP-Module is intended for use with the following Base-PPs:
This SD is mandatory for evaluations of TOEs that claim conformance to a PP-Configuration that includes the PP-Module for :
Virtual Private Network (VPN) Clients, Version 2.4
As such it defines Evaluation Activities for the functionality described in the PP-Module as well as any impacts to the Evaluation Activities to the Base-PP(s) it modifies.
Although Evaluation Activities are defined mainly for the evaluators to follow, in general they also help developers to prepare for evaluation by identifying specific requirements for their TOE.
The specific requirements in Evaluation Activities may in some cases clarify the meaning of Security
Functional Requirements (SFR), and may identify particular requirements for the content of Security
Targets (ST) (especially the TOE Summary Specification), user guidance documentation, and possibly
supplementary information (e.g. for entropy analysis or cryptographic key management architecture).
1.2 Structure of the Document
Evaluation Activities can be defined for both SFRs and Security Assurance Requirements (SAR),
which are themselves defined in separate sections of the SD.
If any Evaluation Activity cannot be successfully completed in an evaluation, then
the overall verdict for the evaluation is a 'fail'.
In rare cases there may be acceptable reasons why an Evaluation Activity
may be modified or deemed not applicable for a particular TOE,
but this must be approved by the Certification Body for the evaluation.
In general, if all Evaluation Activities (for both SFRs and SARs) are successfully
completed in an evaluation then it would be expected that the overall verdict for
the evaluation is a ‘pass’.
To reach a ‘fail’ verdict when the Evaluation Activities have been successfully
completed would require a specific justification from the evaluator as to why the
Evaluation Activities were not sufficient for that TOE.
Similarly, at the more granular level of assurance components, if the Evaluation
Activities for an assurance component and all of its related SFR Evaluation
Activities are successfully completed in an evaluation then it would be expected
that the verdict for the assurance component is a ‘pass’.
To reach a ‘fail’ verdict for the assurance component when these Evaluation
Activities have been successfully completed would require a specific justification
from the evaluator as to why the Evaluation Activities were not sufficient for that TOE.
1.3 Terms
The following sections list Common Criteria and technology terms used in this document.
1.3.1 Common Criteria Terms
Assurance
Grounds for confidence that a TOE meets the SFRs [CC].
Base Protection Profile (Base-PP)
Protection Profile used as a basis to build a PP-Configuration.
Collaborative Protection Profile (cPP)
A Protection Profile developed by
international technical communities and approved by multiple schemes.
Common Criteria (CC)
Common Criteria for Information Technology Security Evaluation (International Standard ISO/IEC 15408).
Common Criteria Testing Laboratory
Within the context of the Common Criteria Evaluation and Validation Scheme (CCEVS), an IT security evaluation facility
accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) and approved by the NIAP Validation Body to conduct Common Criteria-based evaluations.
Common Evaluation Methodology (CEM)
Common Evaluation Methodology for Information Technology Security Evaluation.
Distributed TOE
A TOE composed of multiple components operating as a logical whole.
Extended Package (EP)
A deprecated document form for collecting SFRs that implement a particular protocol, technology,
or functionality. See Functional Packages.
Functional Package (FP)
A document that collects SFRs for a particular protocol, technology,
or functionality.
Operational Environment (OE)
Hardware and software that are outside the TOE boundary that support the TOE functionality and security policy.
Protection Profile (PP)
An implementation-independent set of security requirements for a category of products.
A comprehensive set of security requirements for a product type that consists of at least one Base-PP and at least one PP-Module.
Protection Profile Module (PP-Module)
An implementation-independent statement of security needs for a TOE type complementary to one or more Base-PPs.
Security Assurance Requirement (SAR)
A requirement to assure the security of the TOE.
Security Functional Requirement (SFR)
A requirement for security enforcement by the TOE.
Security Target (ST)
A set of implementation-dependent security requirements for a specific product.
Target of Evaluation (TOE)
The product under evaluation.
TOE Security Functionality (TSF)
The security functionality of the product under evaluation.
TOE Summary Specification (TSS)
A description of how a TOE satisfies the SFRs in an ST.
1.3.2 Technical Terms
Administrator
A user that has administrative privilege to configure the TOE in privileged
mode.
Authorized
An entity granted access privileges to an object, system or system entity.
Critical Security Parameter (CSP)
Security related information, e.g. secret and private cryptographic keys, and
authentication data such as passwords and PINs, whose disclosure or
modification can compromise the security of a cryptographic module.
Entropy Source
This cryptographic function provides a seed for a random number generator
by accumulating the outputs from one or more noise sources. The
functionality includes a measure of the minimum work required to guess a
given output and tests to ensure that the noise sources are operating
properly.
IT Environment
Hardware and software that are outside the TOE boundary that support the
TOE functionality and security policy.
Private Network
A network that is protected from access by unauthorized users or entities.
Privileged Mode
A TOE operational mode that allows a user to perform functions that require
IT Environment administrator privileges.
Public Network
A network that is visible to all users and entities and does not protect against
unauthorized access (e.g. internet).
Threat Agent
An entity that tries to harm an information system through destruction,
disclosure, modification of data, or denial of service.
Unauthorized User
An entity (device or user) who has not been authorized by an authorized
administrator to access the TOE or private network.
Unprivileged Mode
A TOE operational mode that only provides VPN client functions for the VPN
Client user.
VPN Client
The TOE; allows remote users to use client computers to establish an
encrypted IPsec tunnel across an unprotected public network to a private
network.
VPN Client User
A user operating the TOE in unprivileged mode.
VPN Gateway
A component that performs encryption and decryption of IP packets as they
cross the boundary between a private network and a public network.
2 Evaluation Activities for SFRs
The EAs presented in this section capture the actions the evaluator performs
to address technology specific aspects covering specific SARs (e.g. ASE_TSS.1,
ADV_FSP.1, AGD_OPE.1, and ATE_IND.1) – this is in addition to the CEM workunits
that are performed in Section 3 Evaluation Activities for SARs.
Regarding design descriptions (designated by the subsections labeled TSS, as
well as any required supplementary material that may be treated as proprietary),
the evaluator must ensure there is specific information that satisfies the EA.
For findings regarding the TSS section, the evaluator’s verdicts will be
associated with the CEM workunit ASE_TSS.1-1.
Evaluator verdicts associated with the supplementary evidence will also be
associated with ASE_TSS.1-1,
since the requirement to provide such evidence is specified in ASE in the PP.
For ensuring the guidance documentation provides sufficient information for
the administrators/users as it pertains to SFRs, the evaluator’s verdicts will
be associated with CEM workunits ADV_FSP.1-7, AGD_OPE.1-4, and AGD_OPE.1-5.
Finally, the subsection labeled Tests is where the authors have determined
that testing of the product in the context of the associated SFR is necessary.
While the evaluator is expected to develop tests, there may be instances where
it is more practical for the developer to construct tests, or where the
developer may have existing tests.
Therefore, it is acceptable for the evaluator to witness developer-generated
tests in lieu of executing the tests.
In this case, the evaluator must ensure the developer’s tests are executing both
in the manner declared by the developer and as mandated by the EA.
The CEM workunits that are associated with the EAs specified in this section
are: ATE_IND.1-3, ATE_IND.1-4, ATE_IND.1-5, ATE_IND.1-6, and ATE_IND.1-7.
2.1
Protection Profile for General Purpose Operating Systems
The EAs defined in this section are only applicable in cases where the TOE claims conformance
to a PP-Configuration that includes the General Purpose Operating Systems PP.
2.1.1 Modified SFRs
2.1.1.1 Cryptographic Support (FCS)
FCS_CKM.1 Cryptographic Key Generation
FCS_CKM.1
Refer to the evaluation activity for FCS_CKM.1 in the GPOS PP for evaluating this SFR.
FCS_CKM.2 Cryptographic Key Establishment
FCS_CKM.2
Refer to the Assurance Activity for FCS_CKM.2.1 in the GPOS PP for evaluating this SFR. Note that
because a TOE that conforms to this PP-Module must implement IPsec, the tested protocols shall
include IPsec at minimum.
FCS_COP.1/1 Cryptographic Operation (Encryption and Decryption)
FCS_COP.1/1
Refer to the EA for FCS_COP.1(1) in the GPOS PP for evaluating this SFR.
2.1.2 Additional SFRs
2.1.2.1 Cryptographic Support (FCS)
FCS_CKM_EXT.2 Cryptographic Key Storage
FCS_CKM_EXT.2
TSS
Regardless of whether this requirement is met by the VPN client or the OS, the evaluator will check the
TSS to ensure that it lists each persistent secret (credential, secret key) and private key needed to meet
the requirements in the ST. For each of these items, the evaluator will confirm that the TSS lists for what
purpose it is used, and how it is stored.
The evaluator shall review the TSS for to determine that it makes a case that, for each item listed as being
manipulated, it is not written unencrypted to persistent memory, and that the item is
stored by the OS.
Guidance
There are no guidance EAs for this requirement.
Tests
There are no test EAs for this component.
2.1.2.2 Identification and Authentication (FIA)
FIA_X509_EXT.3 X.509 Certificate Use and Management
FIA_X509_EXT.3
The EAs below apply to FIA_X509_EXT.3.2. FIA_X509_EXT.3.1 is evaluated as part of FCS_IPSEC_EXT.1 (and
conditionally as part of FPT_TUD_EXT.1 or FPT_TST_EXT.1) and FIA_X509_EXT.3.3 is evaluated as part
of FCS_IPSEC_EXT.1.11.
TSS
The evaluator shall check the TSS to ensure that it describes whether the VPN client or the OS implements
the certificate validation functionality, how the VPN client/OS chooses which certificates to use, and any
necessary instructions in the administrative guidance for configuring the OS so that desired certificates
can be used.
The evaluator shall examine the TSS to confirm that it describes the behavior of the client/OS when a
connection cannot be established during the validity check of a certificate used in establishing a trusted
channel.
Guidance
If the requirement indicates that the administrator is able to specify the default action, then the evaluator
shall ensure that the operational guidance contains instructions on how this configuration action is
performed.
Tests
The evaluator shall perform the following test regardless of whether the certificate validation functionality
is implemented by the VPN client or by the OS:
Test 1: The evaluator shall demonstrate that using a valid certificate that requires certificate validation
checking to be performed in at least some part by communicating with a non-TOE IT entity. The evaluator
shall then manipulate the environment so that the TOE is unable to verify the validity of the certificate,
and observe that the action selected in FIA_X509_EXT.3.2 is performed. If the selected action is
administrator-configurable, then the evaluator shall follow the operational guidance to determine that all
supported administrator-configurable options behave in their documented manner.
2.1.2.3 Trusted Path/Channels (FTP)
FTP_ITC.1 Inter-TSF Trusted Channel
FTP_ITC.1
TSS
The evaluator shall examine the TSS to determine that it describes the details of the TOE connecting to a
VPN gateway, VPN client, or IPsec-capable network device in terms of the cryptographic
protocols specified in the requirement, along with TOE-specific options or procedures that might not be
reflected in the specification. The evaluator shall also confirm that all protocols listed in the TSS are
specified and included in the requirements in the ST.
Guidance
The evaluator shall confirm that the operational guidance contains instructions for establishing the
connection to a VPN gateway, VPN client, or IPsec-capable network device, and that it contains
recovery instructions should a connection be unintentionally broken.
Tests
The evaluator shall perform the following tests:
Test 1: The evaluator shall ensure that the TOE is able to initiate communications with a VPN gateway,
VPN client, IPsec-capable network device using the protocols specified in the requirement,
setting up the connections as described in the operational guidance and ensuring that communication is
successful.
Test 2: The evaluator shall ensure, for each communication channel with an IPsec peer, the channel data
is not sent in plaintext.
Test 3: The evaluator shall ensure, for each communication channel with an IPsec peer, modification of
the channel data is detected by the TOE.
Test 4: The evaluator shall physically interrupt the connection from the TOE to the IPsec peer. The
evaluators shall ensure that subsequent communications are appropriately protected, at a minimum in
the case of any attempts to automatically resume the connection or connect to a new access point.
Further EAs are associated with requirements for FCS_IPSEC_EXT.1.
2.2
Protection Profile for Mobile Devices
The EAs defined in this section are only applicable in cases where the TOE claims conformance
to a PP-Configuration that includes the Mobile Devices PP.
2.2.1 Modified SFRs
2.2.1.1 Cryptographic Support (FCS)
FCS_CKM.1 Cryptographic Key Generation
FCS_CKM.1
Refer to the EAs for FCS_CKM.1 in the MDF PP. The only change to this SFR is that some selections are
mandated, therefore the corresponding testing is mandatory. The actual testing for those selections is not
changed.
Refer to the EAs for FCS_CKM.2/UNLOCKED in the MDF PP. The only change to this SFR is that some
selections are mandated, therefore the corresponding testing is mandatory. The actual testing for those
selections is not changed.
FCS_COP.1/ENCRYPT Cryptographic Operation
FCS_COP.1/ENCRYPT
Refer to the EAs for FCS_COP.1/ENCRYPT in the MDF PP. The only change to this SFR is that some
selections are mandated, therefore the corresponding testing is mandatory. The actual testing for those
selections is not changed.
2.2.1.2 User Data Protection (FDP)
FDP_IFC_EXT.1 Subset Information Flow Control
FDP_IFC_EXT.1
Refer to the EAs for FDP_IFC_EXT.1 in the MDF PP. The only change to this SFR is that some selections are
mandated, therefore the corresponding testing is mandatory. The actual testing for those selections is not
changed.
2.2.1.3 Identification and Authentication (FIA)
FIA_X509_EXT.2 X.509 Certificate Authentication
FIA_X509_EXT.2
Refer to the EAs for FIA_X509_EXT.2 in the MDF PP. The only change to this SFR is that some selections
are mandated, therefore the corresponding testing is mandatory. The actual testing for those selections
is not changed.
2.2.1.4 Security Management (FMT)
FMT_SMF_EXT.1 Specification of Management Functions
FMT_SMF_EXT.1
Refer to the EAs for FMT_SMF_EXT.1 in the MDF PP. The only change to this SFR is the change to management function 45.
Testing of all other functions is not affected.
2.2.1.5 Trusted Path/Channels (FTP)
FTP_ITC_EXT.1 Trusted Channel Communication
FTP_ITC_EXT.1
Refer to the EAs for FTP_ITC_EXT.1 in the MDF PP. The only change to this SFR is that some selections are
mandated, therefore the corresponding testing is mandatory. The actual testing for those selections is not
changed.
2.3
Protection Profile for Application Software
The EAs defined in this section are only applicable in cases where the TOE claims conformance
to a PP-Configuration that includes the Application Software PP.
For all key establishment schemes refer to the EA for FCS_CKM.2 in the App PP.
FCS_CKM.1 Cryptographic Key Generation Services
FCS_CKM.1
This SFR is evaluated in conjunction with FCS_CKM.1/AK in the App PP.
FCS_COP.1/SKC Cryptographic Operation
FCS_COP.1/SKC
TSS
If the TSF implements AES cryptography in support of both credential encryption (per FCS_STO_EXT.1)
and IPsec, the evaluator shall examine the TSS to ensure that it clearly identifies the modes and key sizes
that are supported for each usage of AES.
Guidance
There are no operational beyond what is required by the EA for FCS_COP.1/SKC in the App PP.
Tests
There are no test EAs beyond what is required by the EA for FCS_COP.1/SKC in the App PP.
2.3.1.2 Identification and Authentication (FIA)
FIA_X509_EXT.2 X.509 Certificate Authentication
FIA_X509_EXT.2
Refer to the EA for FIA_X509_EXT.2 in the App PP.
2.3.1.3 Trusted Path/Channels (FTP)
FTP_DIT_EXT.1 Protection of Data in Transit
FTP_DIT_EXT.1
For IPsec, refer to the EA for FCS_IPSEC_EXT.1. If other protocols are selected
for FTP_DIT_EXT.1, refer to the EA for FTP_DIT_EXT.1 in the App PP.
2.3.2 Additional SFRs
2.3.2.1 Cryptographic Support (FCS)
FCS_CKM_EXT.2 Cryptographic Key Storage
FCS_CKM_EXT.2
TSS
Regardless of whether this requirement is met by the TOE or the TOE platform, the evaluator will check
the TSS to ensure that it lists each persistent secret (credential, secret key) and private key needed to
meet the requirements in the ST. For each of these items, the evaluator will confirm that the TSS lists for
what purpose it is used, and how it is stored. The evaluator then performs the following actions:
Persistent secrets and private keys manipulated by the platform:
For each platform listed in the ST, the evaluator shall examine the ST of the platform to ensure that the
persistent secrets and private keys listed as being stored by the platform in the VPN client ST are identified
as being protected in that platform's ST
Persistent secrets and private keys manipulated by the TOE:
The evaluator reviews the TSS for to determine that it makes a case that, for each item listed as being
manipulated by the TOE, it is not written unencrypted to persistent memory, and that the item is stored
by the platform.
Guidance
There are no guidance EAs for this requirement.
Tests
There are no test EAs for this requirement.
FCS_CKM_EXT.4 Cryptographic Key Destruction
FCS_CKM_EXT.4
TSS
The evaluator shall ensure that all plaintext secret and private cryptographic keys and CSPs (whether
manipulated by the TOE or exclusively by the platform) are identified in the VPN Client ST's TSS, and that
they are accounted for by the EAs in this section.
Requirement met by the platform:
The evaluator shall check to ensure the TSS describes each of the secret keys (keys used for
symmetric encryption), private keys, and CSPs used to generate key that are not otherwise covered
by the FCS_CKM_EXT.4 requirement levied on the TOE.
For each platform listed in the ST, the evaluator shall examine the TSS of the ST of the platform to
ensure that each of the secret keys, private keys, and CSPs used to generate key listed above are
covered.
Requirement met by the TOE:
The evaluator shall check to ensure the TSS describes when each of the plaintext keys are cleared (e.g.,
system power off, disconnection of an IPsec connection, when no longer needed by the VPN channel per
the protocol); and the type of clearing procedure that is performed (cryptographic erase, overwrite with
zeros, overwrite three or more times by a different alternating pattern, overwrite with random pattern,
or block erase). If different types of memory are used to store the materials to be protected, the evaluator
shall check to ensure that the TSS describes the clearing procedure in terms of the memory in which the
data are stored (for example, "secret keys stored on flash are cleared by overwriting once with zeros,
while secret keys stored on the internal persistent storage device are cleared by overwriting three times
with a random pattern that is changed before each write").
Guidance
There are no guidance EAs for this requirement.
Tests
For each key clearing situation described in the TSS, the evaluator shall repeat the following test.
Test 1: The evaluator shall use appropriate combinations of specialized OE and
development tools (debuggers, simulators, etc.) for the TOE and instrumented TOE builds to test that keys
are cleared correctly, including all intermediate copies of the key that may have been created internally
by the TOE during normal cryptographic processing with that key.
Cryptographic TOE implementations in software shall be loaded and exercised under a debugger to
perform such tests. The evaluator shall perform the following test for each key subject to clearing,
including intermediate copies of keys that are persisted encrypted by the TOE:
Load the instrumented TOE build in a debugger.
Record the value of the key in the TOE subject to clearing.
Cause the TOE to perform a normal cryptographic processing with the key from #1.
Cause the TOE to clear the key.
Cause the TOE to stop the execution but not exit.
Cause the TOE to dump the entire memory footprint of the TOE into a binary file.
Search the content of the binary file created in #4 for instances of the known key value from
#1.
The test succeeds if no copies of the key from #1 are found in step #7 above and fails otherwise.
The evaluator shall perform this test on all keys, including those persisted in encrypted form, to ensure
intermediate copies are cleared.
2.4
Protection Profile for MDMs
The EAs defined in this section are only applicable in cases where the TOE claims conformance
to a PP-Configuration that includes the MDM PP.
2.4.1 Modified SFRs
2.4.1.1 Cryptographic Support (FCS)
FCS_CKM.1 Cryptographic Key Generation
FCS_CKM.1
Refer to the EA for FCS_CKM.1 in the MDM PP.
FCS_CKM.2 Cryptographic Key Establishment
FCS_CKM.2
Refer to the EA for FCS_CKM.2 in the MDM PP.
FCS_COP.1/1 Cryptographic Operation
FCS_COP.1/1
Refer to the EA for FCS_COP.1(1) in the MDM PP.
2.4.1.2 Identification and Authentication (FIA)
FIA_X509_EXT.2 X.509 Certificate Authentication
FIA_X509_EXT.2
Refer to the EA for FIA_X509_EXT.2 in the MDM PP.
2.4.1.3 Protection of the TSF (FPT)
FPT_ITT.1/1 Basic Internal TSF Data Transfer Protection
FPT_ITT.1/1
Refer to the EA for FPT_ITT.1(1) in the MDM PP. Note that the PP-Module does not require any separate
testing for this if IPsec is not used to implement this function.
2.4.1.4 Trusted Path/Channels (FTP)
FTP_ITC.1/1 Inter-TSF Trusted Channel (Authorized IT Entities)
FTP_ITC.1/1
Refer to the EA for FTP_ITC.1(1) in the MDM PP. Note that the PP-Module does not require any separate
testing for this if IPsec is not used to implement this function.
Refer to the EA for FTP_TRP.1(1) in the MDM PP. Note that the PP-Module does not require any
separate testing for this if IPsec is not used to implement this function.
The evaluator shall examine the TSS to verify that it describes how the key generation functionality is
invoked.
Guidance
There are no guidance EAs for this requirement.
Tests
If this functionality is implemented by the TSF, refer to the following EAs, depending on the TOE’s
claimed Base-PP:
GPOS PP: FCS_CKM.1
MDF PP: FCS_CKM.1
App PP: FCS_CKM.1/AK
MDM PP: FCS_CKM.1
FCS_IPSEC_EXT.1 IPsec
FCS_IPSEC_EXT.1
TSS
In addition to the TSS EAs for the individual FCS_IPSEC_EXT.1 elements below, the evaluator shall perform
the following:
If the TOE boundary includes a general-purpose OS or mobile device, the evaluator shall
examine the TSS to ensure that it describes whether the VPN client capability is architecturally integrated
with the platform itself or whether it is a separate executable that is bundled with the platform.
Guidance
In addition to the Operational for the individual FCS_IPSEC_EXT.1 elements below, the
evaluator shall perform the following:
If the configuration of the IPsec behavior is from an environmental source, most notably a VPN gateway
(e.g through receipt of required connection parameters from a VPN gateway), the evaluator shall ensure
that the operational guidance contains any appropriate information for ensuring that this configuration
can be properly applied.
Note in this case that the implementation of the IPsec protocol must be enforced entirely within the TOE
boundary; i.e. it is not permissible for a software application TOE to be a graphical front-end for IPsec
functionality implemented totally or in part by the underlying OS platform. The behavior referenced here
is for the possibility that the configuration of the IPsec connection is initiated from outside the TOE, which
is permissible so long as the TSF is solely responsible for enforcing the configured behavior. However, it is
allowable for the TSF to rely on low-level platform-provided networking functions to implement the SPD
from the client (e.g., enforcement of packet routing decisions).
Tests
As a prerequisite for performing the Test EAs for the individual FCS_IPSEC_EXT.1 elements below, the
evaluator shall do the following:
The evaluator shall minimally create a test environment equivalent to the test environment illustrated
below. It is expected that the traffic generator is used to construct network packets and will provide the
evaluator with the ability manipulate fields in the ICMP, IPv4, IPv6, UDP, and TCP packet headers. The
evaluator shall provide justification for any differences in the test environment.
Note that the evaluator shall perform all tests using the VPN client and a representative sample of
platforms listed in the ST (for TOEs that claim to support multiple platforms).
FCS_IPSEC_EXT.1.1
TSS
The evaluator shall examine the TSS and determine that it describes how the IPsec capabilities are
implemented.
If the TOE is a standalone software application, the evaluator shall ensure that the TSS asserts that all
IPsec functionality is implemented by the TSF. The evaluator shall also ensure that the TSS identifies what
platform functionality the TSF relies upon to support its IPsec implementation, if any (e.g. does it invoke
cryptographic primitive functions from the platform’s cryptographic library, enforcement of packet
routing decisions by low-level network drivers).
If the TOE is part of a general-purpose desktop or mobile OS, the evaluator shall ensure
that the TSS describes at a high level the architectural relationship between the VPN client portion of the
TOE and the rest of the TOE (e.g. is the VPN client an integrated part of the OS or is it a standalone
executable that is bundled into the OS package). If the SPD is implemented by the underlying platform in
this case, then the TSS describes how the client interacts with the platform to establish and populate the
SPD, including the identification of the platform's interfaces that are used by the client.
In all cases, the evaluator shall also ensure that the TSS describes how the client interacts with the network
stack of the platforms on which it can run (e.g., does the client insert itself within the stack via kernel
mods, does the client simply invoke APIs to gain access to network services).
The evaluator shall ensure that the TSS describes how the SPD is implemented and the rules for processing
both inbound and outbound packets in terms of the IPsec policy. The TSS describes the rules that are
available and the resulting actions available after matching a rule. The TSS describes how the available
rules and actions form the SPD using terms defined in RFC 4301 such as BYPASS (e.g., no encryption),
DISCARD (e.g., drop the packet), and PROTECT (e.g., encrypt the packet) actions defined in RFC 4301.
As noted in section 4.4.1 of RFC 4301, the processing of entries in the SPD is non-trivial and the evaluator
shall determine that the description in the TSS is sufficient to determine which rules will be applied given
the rule structure implemented by the TOE. For example, if the TOE allows specification of ranges,
conditional rules, etc., the evaluator shall determine that the description of rule processing (for both
inbound and outbound packets) is sufficient to determine the action that will be applied, especially in the
case where two different rules may apply. This description shall cover both the initial packets (that is, no
SA is established on the interface or for that particular packet) as well as packets that are part of an
established SA.
Guidance
The evaluator shall examine the operational guidance to verify it describes how the SPD is created and
configured. If there is an administrative interface to the client, then the guidance describes how the
administrator specifies rules for processing a packet. The description includes all three cases - a rule that
ensures packets are encrypted/decrypted, dropped, and allowing a packet to flow in plaintext. The
evaluator shall determine that the description in the operational guidance is consistent with the
description in the TSS, and that the level of detail in the operational guidance is sufficient to allow the
administrator to set up the SPD in an unambiguous fashion. This includes a discussion of how ordering of
rules impacts the processing of an IP packet.
If the client is configured by an external application, such as the VPN gateway, then the operational
guidance should indicate this and provide a description of how the client is configured by the external
application. The description should contain information as to how the SPD is established and set up in an
unambiguous fashion. The description should also include what is configurable via the external
application, how ordering of entries may be expressed, as well as the impacts that ordering of entries may
have on the packet processing.
In either case, the evaluator ensures the description provided In the TSS is consistent with the capabilities
and description provided in the operational guidance.
Tests
Depending on the implementation, the evaluator may be required to use a VPN gateway or some form of
application to configure the client. For Test 2, the evaluator is required to choose an application that
allows for the configuration of the full set of capabilities of the VPN client (in conjunction with the
platform). For example, if the client provides a robust interface that allows for specification of wildcards,
subnets, etc., it is unacceptable for the evaluator to choose a VPN Gateway that only allows for specifying
a single fully qualified IP addresses in the rule.
The evaluator shall perform the following tests:
Test 1: The evaluator shall configure an SPD on the client that is capable of the following: dropping a
packet, encrypting a packet, and allowing a packet to flow in plaintext. The selectors used in the
construction of the rule shall be different such that the evaluator can generate a packet and send packets
to the client with the appropriate fields (fields that are used by the rule - e.g., the IP addresses, TCP/UDP
ports) in the packet header. The evaluator performs both positive and negative test cases for each type
of rule. The evaluator observes via the audit trail, and packet captures that the TOE exhibited the expected
behavior: appropriate packets were dropped, allowed through without modification, was encrypted by
the IPsec implementation.
Test 2: The evaluator shall devise several tests that cover a variety of scenarios for packet processing.
These scenarios must exercise the range of possibilities for SPD entries and processing modes as outlined
in the TSS and operational guidance. Potential areas to cover include rules with overlapping ranges and
conflicting entries, inbound and outbound packets, and packets that establish SAs as well as packets that
belong to established SAs. The evaluator shall verify, via the audit trail and packet captures, for each
scenario that the expected behavior is exhibited, and is consistent with both the TSS and the operational
guidance.
FCS_IPSEC_EXT.1.2
TSS
The evaluator shall check the TSS to ensure it states that the VPN can be established to operate in tunnel
mode, transport mode, or either mode (as selected).
Guidance
The evaluator shall confirm that the operational guidance contains instructions on how to configure the
connection in each mode selected.
If both transport mode and tunnel mode are implemented, the evaluator shall review the operational
guidance to determine how the use of a given mode is specified.
Tests
The evaluator shall perform the following tests based on the selections chosen:
Test 1: [conditional]: If tunnel mode is selected, the evaluator uses the operational guidance to configure
the TOE to operate in tunnel mode and also configures a VPN gateway to operate in tunnel mode. The
evaluator configures the TOE and the VPN gateway to use any of the allowable cryptographic algorithms,
authentication methods, etc. to ensure an allowable SA can be negotiated. The evaluator shall then
initiate a connection from the client to connect to the VPN GW peer. The evaluator observes (for example,
in the audit trail and the captured packets) that a successful connection was established using the tunnel
mode.
Test 2: [conditional]: If transport mode is selected, the evaluator uses the operational guidance to
configure the TOE to operate in transport mode and also configures an IPsec peer to accept IPsec
connections using transport mode. The evaluator configures the TOE and the endpoint device to use any
of the allowed cryptographic algorithms, authentication methods, etc. to ensure an allowable SA can be
negotiated. The evaluator then initiates a connection from the TOE to connect to the remote endpoint.
The evaluator observes (for example, in the audit trail and the captured packets) that a successful
connection was established using the transport mode.
Test 3: [conditional]: If both tunnel mode and transport mode are selected, the evaluator shall perform
both Test 1 and Test 2 above, demonstrating that the TOE can be configured to support both modes.
Test 4: [conditional]: If both tunnel mode and transport mode are selected, the evaluator shall modify the
testing for FCS_IPSEC_EXT.1 to include the supported mode for SPD PROTECT entries to show that they
only apply to traffic that is transmitted or received using the indicated mode.
FCS_IPSEC_EXT.1.3
TSS
The evaluator shall examine the TSS to verify that the TSS provides a description of how a packet is
processed against the SPD and that if no “rules” are found to match, that a final rule exists, either implicitly
or explicitly, that causes the network packet to be discarded.
Guidance
The evaluator shall check that the operational guidance provides instructions on how to construct or
acquire the SPD and uses the guidance to configure the TOE for the following test.
Tests
The evaluator shall perform the following test:
Test 1:
The evaluator shall configure the SPD such that it has entries that contain operations that DISCARD,
PROTECT, and (if applicable) BYPASS network packets. The evaluator may use the SPD that was created
for verification of FCS_IPSEC_EXT.1.1. The evaluator shall construct a network packet that matches a
BYPASS entry and send that packet. The evaluator should observe that the network packet is passed to
the proper destination interface with no modification. The evaluator shall then modify a field in the packet
header; such that it no longer matches the evaluator-created entries (there may be a “TOE-created” final
entry that discards packets that do not match any previous entries). The evaluator sends the packet, and
observes that the packet was not permitted to flow to any of the TOE’s interfaces.
FCS_IPSEC_EXT.1.4
TSS
The evaluator shall examine the TSS to verify that the algorithms AES-GCM-128 and AES-GCM-256 are
implemented. If the ST author has selected either AES-CBC-128 or AES-CBC-256 in the requirement, then
the evaluator verifies the TSS describes these as well. In addition, the evaluator ensures that the SHA-
based HMAC algorithm conforms to the algorithms specified in the relevant iteration of FCS_COP.1 from
the Base-PP that applies to keyed-hash message authentication.
Guidance
The evaluator checks the operational guidance to ensure it provides instructions on how the TOE is
configured to use the algorithms selected in this component and whether this is performed through direct
configuration, defined during initial installation, or defined by acquiring configuration settings from an
environmental component.
Tests
Test 1:
The evaluator shall configure the TOE as indicated in the operational guidance configuring the TOE
to using each of the AES-GCM-128, and AES-GCM-256 algorithms, and attempt to establish a connection
using ESP. If the ST Author has selected either AES-CBC-128 or AES-CBC-256, the TOE is configured to use
those algorithms and the evaluator attempts to establish a connection using ESP for those algorithms
selected.
FCS_IPSEC_EXT.1.5
TSS
The evaluator shall examine the TSS to verify that IKEv1, IKEv2, or both IKEv1 and IKEv2 are implemented. If IKEv1 is
implemented, the evaluator shall verify that the TSS indicates whether or not XAUTH is supported, and
that aggressive mode is not used for IKEv1 Phase 1 exchanges (i.e. only main mode is used). It may be that
these are configurable options.
Guidance
The evaluator shall check the operational guidance to ensure it instructs the administrator how to
configure the TOE to use IKEv1, IKEv2, or both (as selected), and uses the guidance to configure the TOE to
perform NAT traversal for the test below. If XAUTH is implemented, the evaluator shall verify that the
operational guidance provides instructions on how it is enabled or disabled.
If the TOE supports IKEv1, the evaluator shall verify that the operational guidance either asserts that only
main mode is used for Phase 1 exchanges, or provides instructions for disabling aggressive mode.
Tests
Test 1: The evaluator shall configure the TOE so that it will perform NAT traversal processing as described
in the TSS and RFC 7296, section 2.23. The evaluator shall initiate an IPsec connection and determine that
the NAT is successfully traversed. If the TOE supports IKEv1 with or without XAUTH, the evaluator shall
verify that this test can be successfully repeated with XAUTH enabled and disabled in the manner specified
by the operational guidance. If the TOE only supports IKEv1 with XAUTH, the evaluator shall verify that
connections not using XAUTH are unsuccessful. If the TOE only supports IKEv1 without XAUTH, the
evaluator shall verify that connections using XAUTH are unsuccessful.
Test 2: [conditional]: If the TOE supports IKEv1, the evaluator shall perform any applicable operational
guidance steps to disable the use of aggressive mode and then attempt to establish a connection using an
IKEv1 Phase 1 connection in aggressive mode. This attempt should fail. The evaluator shall show that the
TOE will reject a VPN gateway from initiating an IKEv1 Phase 1 connection in aggressive mode. The
evaluator should then show that main mode exchanges are supported.
FCS_IPSEC_EXT.1.6
TSS
The evaluator shall ensure the TSS identifies the algorithms used for encrypting the IKE
payload for each supported IKE version, and that the algorithms AES-CBC-128, AES-CBC-256 are specified, and if others are chosen in the
selection of the requirement, those are included in the TSS discussion.
Guidance
The evaluator checks the operational guidance to ensure it provides instructions on how the TOE is
configured to use the algorithms selected in this component and whether this is performed through direct
configuration, defined during initial installation, or defined by acquiring configuration settings from an
environmental component.
Tests
The evaluator shall use the operational guidance to configure the TOE (or to configure the OE
to have the TOE receive configuration) to perform the following test for each ciphersuite
selected:
Test 1:
The evaluator shall configure the TOE to use the ciphersuite under test to encrypt the IKE payload for each
supported IKE version and establish a connection with a peer device, which is configured to only accept the
payload encrypted using the indicated ciphersuite. The evaluator will confirm the algorithm was that used
in the negotiation. The evaluator will confirm that the connection is successful by confirming that data
can be passed through the connection once it is established. For example, the evaluator may connect to
a webpage on the remote network and verify that it can be reached.
FCS_IPSEC_EXT.1.7
TSS
There are no TSS EAs for this requirement.
Guidance
The evaluator shall check the operational guidance to ensure it provides instructions on how the TOE
configures the values for SA lifetimes. In addition, the evaluator shall check that the guidance has the
option for either the Administrator or VPN Gateway to configure Phase 1 SAs if time-based limits are
supported. Currently there are no values mandated for the number of packets or number of bytes, the
evaluator shall simply check the operational guidance to ensure that this can be configured if selected in
the requirement.
Tests
When testing this functionality, the evaluator needs to ensure that both sides are configured
appropriately. From the RFC “A difference between IKEv1 and IKEv2 is that in IKEv1 SA lifetimes were
negotiated. In IKEv2, each end of the SA is responsible for enforcing its own lifetime policy on the SA and
rekeying the SA when necessary. If the two ends have different lifetime policies, the end with the shorter
lifetime will end up always being the one to request the rekeying. If the two ends have the same lifetime
policies, it is possible that both will initiate a rekeying at the same time (which will result in redundant
SAs). To reduce the probability of this happening, the timing of rekeying requests SHOULD be jittered.”
Each of the following tests shall be performed for each version of IKE selected in the
FCS_IPSEC_EXT.1.5 protocol selection:
Test 1: [conditional]: The evaluator shall configure a maximum lifetime in terms of the # of packets (or
bytes) allowed following the operational guidance. The evaluator shall establish an SA and determine that
once the allowed # of packets (or bytes) through this SA is exceeded, the connection is closed.
Test 2: [conditional]: The evaluator shall construct a test where a Phase 1 SA is established and attempted
to be maintained for more than 24 hours before it is renegotiated. The evaluator shall observe that this
SA is closed or renegotiated in 24 hours or less. If such an action requires that the TOE be configured in a
specific way, the evaluator shall implement tests demonstrating that the configuration capability of the
TOE works as documented in the operational guidance.
Test 3: [conditional]: The evaluator shall perform a test similar to Test 2 for Phase 2 SAs, except that the
lifetime will be 8 hours or less instead of 24 hours or less.
Test 4: [conditional]: If a fixed limit for IKEv1 SAs is supported, the evaluator shall establish an SA and
observe that the connection is closed after the fixed traffic or time value is reached.
FCS_IPSEC_EXT.1.8
TSS
The evaluator shall check to ensure that the DH groups specified in the requirement are listed as being
supported in the TSS. If there is more than one DH group supported, the evaluator checks to ensure the
TSS describes how a particular DH group is specified/negotiated with a peer.
Guidance
There are no guidance EAs for this requirement.
Tests
The evaluator shall perform the following test:
Test 1: For each supported DH group, the evaluator shall test to ensure that all supported IKE
protocols can be successfully completed using that particular DH group.
FCS_IPSEC_EXT.1.9
TSS
The evaluator shall check to ensure that, for each DH group supported, the TSS describes the process for
generating "x" (as defined in FCS_IPSEC_EXT.1.9) and each nonce. The evaluator shall verify that the TSS
indicates that the random number generated that meets the requirements in this EP is used, and that the
length of "x" and the nonces meet the stipulations in the requirement.
Guidance
There are no guidance EAs for this requirement.
Tests
There are no test EAs for this requirement.
FCS_IPSEC_EXT.1.10
EAs for this element are tested through EAs for FCS_IPSEC_EXT.1.9.
FCS_IPSEC_EXT.1.11
TSS
The evaluator shall ensures that the TSS whether peer authentication is performed using RSA, ECDSA, or both.
If any selection with pre-shared keys is chosen in the selection, the evaluator shall check to ensure that the TSS describes
how those selections work in conjunction with authentication of IPsec connections.
The evaluator shall ensure that the TSS describes how the TOE compares the peer’s presented identifier
to the reference identifier. This description shall include whether the certificate presented identifier is
compared to the ID payload presented identifier, which fields of the certificate are used as the presented
identifier (DN, Common Name, or SAN) and, if multiple fields are supported, the logical order comparison.
If the ST author assigned an additional identifier type, the TSS description shall also include a description
of that type and the method by which that type is compared to the peer’s presented certificate.
Guidance
If any selection with “Pre-shared Keys” is selected, the evaluator shall check that the operational guidance
describes any configuration necessary to enable any selected authentication mechanisms.
If any method other than no other method is selected, the evaluator shall check that the operational guidance describes any
configuration necessary to enable any selected authentication mechanisms.
The evaluator ensures the operational guidance describes how to set up the TOE to use the cryptographic
algorithms RSA, ECDSA, or either, depending which is claimed in the ST.
In order to construct the environment and configure the TOE for the following tests, the evaluator will
ensure that the operational guidance also describes how to configure the TOE to connect to a trusted CA,
and ensure a valid certificate for that CA is loaded into the TOE as a trusted CA.
The evaluator shall also ensure that the operational guidance includes the configuration of the reference
identifiers for the peer.
Tests
For efficiency’s sake, the testing that is performed here has been combined with the testing for
FIA_X509_EXT.2 and FIA_X509_EXT.3 (for IPsec connections and depending on the Base-PP),
FCS_IPSEC_EXT.1.12, and FCS_IPSEC_EXT.1.13. The following tests shall be repeated for each peer
authentication protocol selected in the FCS_IPSEC_EXT.1.11 selection above:
Test 1: The evaluator shall have the TOE generate a public-private key pair, and submit a CSR (Certificate
Signing Request) to a CA (trusted by both the TOE and the peer VPN used to establish a connection) for
its signature. The values for the DN (Common Name, Organization, Organizational Unit, and Country) will
also be passed in the request. Alternatively, the evaluator may import to the TOE a previously generated
private key and corresponding certificate.
Test 2: The evaluator shall configure the TOE to use a private key and associated certificate signed by a
trusted CA and shall establish an IPsec connection with the peer.
Test 3: The evaluator shall test that the TOE can properly handle revoked certificates – conditional on
whether CRL or OCSP is selected; if both are selected, and then a test is performed for each method. For
this current version of the PP-Module, the evaluator has to only test one up in the trust chain (future
drafts may require to ensure the validation is done up the entire chain). The evaluator shall ensure that a
valid certificate is used, and that the SA is established. The evaluator then attempts the test with a
certificate that will be revoked (for each method chosen in the selection) to ensure when the certificate
is no longer valid that the TOE will not establish an SA
Test 4: [conditional]: For each selection made, the evaluator shall verify factors are required, as indicated in the
operational guidance, to establish an IPsec connection with the server.
For each supported identifier type (excluding DNs), the evaluator shall repeat the following tests:
Test 5: For each field of the certificate supported for comparison, the evaluator shall configure the peer’s
reference identifier on the TOE (per the administrative guidance) to match the field in the peer’s
presented certificate and shall verify that the IKE authentication succeeds.
Test 6: For each field of the certificate support for comparison, the evaluator shall configure the peer’s
reference identifier on the TOE (per the administrative guidance) to not match the field in the peer’s
presented certificate and shall verify that the IKE authentication fails.
The following tests are conditional:
Test 7: [conditional]: If, according to the TSS, the TOE supports both Common Name and SAN certificate
fields and uses the preferred logic outlined in the Application Note, the tests above with the Common
Name field shall be performed using peer certificates with no SAN extension. Additionally, the evaluator
shall configure the peer’s reference identifier on the TOE to not match the SAN in the peer’s presented
certificate but to match the Common Name in the peer’s presented certificate, and verify that the IKE
authentication fails.
Test 8: [conditional]: If the TOE supports DN identifier types, the evaluator shall configure the peer's
reference identifier on the TOE (per the administrative guidance) to match the subject DN in the peer's
presented certificate and shall verify that the IKE authentication succeeds. To demonstrate a bit-wise
comparison of the DN, the evaluator shall change a single bit in the DN (preferably, in an Object Identifier
(OID) in the DN) and verify that the IKE authentication fails. To demonstrate a comparison of DN values,
the evaluator shall change any one of the four DN values and verify that the IKE authentication fails.
Test 9: [conditional]: If the TOE supports both IPv4 and IPv6 and supports IP address identifier types, the
evaluator must repeat test 1 and 2 with both IPv4 address identifiers and IPv6 identifiers. Additionally,
the evaluator shall verify that the TOE verifies that the IP header matches the identifiers by setting the
presented identifiers and the reference identifier with the same IP address that differs from the actual IP
address of the peer in the IP headers and verifying that the IKE authentication fails.
Test 10: [conditional]: If, according to the TSS, the TOE performs comparisons between the peer’s ID
payload and the peer’s certificate, the evaluator shall repeat the following test for each combination of
supported identifier types and supported certificate fields (as above). The evaluator shall configure the
peer to present a different ID payload than the field in the peer’s presented certificate and verify that the
TOE fails to authenticate the IKE peer.
FCS_IPSEC_EXT.1.12
EAs for this element are tested through EAs for FCS_IPSEC_EXT.1.11.
FCS_IPSEC_EXT.1.13
EAs for this element are tested through EAs for FCS_IPSEC_EXT.1.11.
FCS_IPSEC_EXT.1.14
TSS
The evaluator shall check that the TSS describes the potential strengths (in terms of the number of bits in
the symmetric key) of the algorithms that are allowed for the IKE and ESP exchanges. The TSS shall also
describe the checks that are done when negotiating IKEv1 Phase 2 or IKEv2 CHILD_SA suites (depending on the supported IKE versions) to ensure
that the strength (in terms of the number of bits of key in the symmetric algorithm) of the negotiated
algorithm is less than or equal to that of the IKE SA this is protecting the negotiation.
Guidance
There are no guidance EAs for this requirement.
Tests
The evaluator follows the guidance to configure the TOE to perform the following tests:
Test 1: This test shall be performed for each version of IKE supported. The evaluator shall successfully
negotiate an IPsec connection using each of the supported algorithms and hash functions identified in the
requirements.
Test 2: [conditional]: This test shall be performed for each version of IKE supported. The evaluator shall
attempt to establish an SA for ESP that selects an encryption algorithm with more strength than that being
used for the IKE SA (i.e., symmetric algorithm with a key size larger than that being used for the IKE SA).
Such attempts should fail.
Test 3: This test shall be performed for each version of IKE supported. The evaluator shall attempt to
establish an IKE SA using an algorithm that is not one of the supported algorithms and hash functions
identified in the requirements. Such an attempt should fail.
Test 4: This test shall be performed for each version of IKE supported. The evaluator shall attempt to
establish an SA for ESP (assumes the proper parameters where used to establish the IKE SA) that selects
an encryption algorithm that is not identified in FCS_IPSEC_EXT.1.4. Such an attempt should fail.
2.5.2 User Data Protection (FDP)
FDP_RIP.2 Full Residual Information Protection
FDP_RIP.2
TSS
Requirement met by the platform
The evaluator shall examine the TSS to verify that it describes (for each supported platform) the extent to
which the client processes network packets and addresses the FDP_RIP.2 requirement.
Requirement met by the TOE
“Resources” in the context of this requirement are network packets being sent through (as opposed to
“to”, as is the case when a security administrator connects to the TOE) the TOE. The concern is that once
a network packet is sent, the buffer or memory area used by the packet still contains data from that
packet, and that if that buffer is re-used, those data might remain and make their way into a new packet.
The evaluator shall check to ensure that the TSS describes packet processing to the extent that they can
determine that no data will be reused when processing network packets. The evaluator shall ensure that
this description at a minimum describes how the previous data are zeroized/overwritten, and at what
point in the buffer processing this occurs.
Guidance
There are no guidance EAs for this requirement.
Tests
There are no test EAs for this requirement.
2.5.3 Security Management (FMT)
FMT_SMF.1/VPN Specification of Management Functions (VPN)
FMT_SMF.1/VPN
TSS
The evaluator shall check to ensure the TSS describes the client credentials and how they are used by the
TOE.
Guidance
The evaluator shall check to make sure that every management function mandated in the ST for this
requirement is described in the operational guidance and that the description contains the information
required to perform the management duties associated with each management function.
Tests
The evaluator shall test the TOE’s ability to provide the management functions by configuring the TOE
according to the operational guidance and testing each management activity listed in the ST.
The evaluator shall ensure that all management functions claimed in the ST can be performed by
completing activities described in the AGD. Note that this may be performed in the course of completing
other testing.
2.5.4 Protection of the TSF (FPT)
FPT_TST_EXT.1/VPN TSF Self-Test
FPT_TST_EXT.1/VPN
Except for where it is explicitly noted, the evaluator is expected to check the following information
regardless of whether the functionality is implemented by the TOE or by the TOE platform.
TSS
The evaluator shall examine the TSS to ensure that it details the self-tests that are run by the TSF on
startup; this description should include an outline of what the tests are actually doing (e.g., rather than saying
"memory is tested," a description similar to "memory is tested by writing a value to each memory location
and reading it back to ensure it is identical to what was written" shall be used). The evaluator shall ensure
that the TSS makes an argument that the tests are sufficient to demonstrate that the TSF is operating
correctly. If some of the tests are performed by the TOE platform, the evaluator shall check the TSS to
ensure that those tests are identified, and that the ST for each platform contains a description of those
tests. Note that the tests that are required by this component are those that support security functionality
in the VPN Client PP-Module, which may not correspond to the set of all self-tests contained in the
platform STs.
The evaluator shall examine the TSS to ensure that it describes how the integrity of stored TSF executable
code is cryptographically verified when it is loaded for execution. The evaluator shall ensure that the TSS
makes an argument that the tests are sufficient to demonstrate that the integrity of stored TSF executable
code has not been compromised. The evaluator shall check to ensure that the cryptographic requirements
listed are consistent with the description of the integrity verification process.
The evaluator also ensures that the TSS (or the operational guidance) describes the actions that take place
for successful (e.g. hash verified) and unsuccessful (e.g., hash not verified) cases. For checks implemented
entirely by the platform, the evaluator ensures that the operational guidance for the TOE references or
includes the platform-specific guidance for each platform listed in the ST.
Guidance
If not present in the TSS, the evaluator ensures that the operational guidance describes the actions that
take place for successful (e.g. hash verified) and unsuccessful (e.g., hash not verified) cases. For checks
implemented entirely by the platform, the evaluator ensures that the operational guidance for the TOE
references or includes the platform-specific guidance for each platform listed in the ST.
Tests
The evaluator shall perform the following tests:
Test 1: The evaluator performs the integrity check on a known good TSF executable and verifies that the
check is successful.
Test 2: The evaluator modifies the TSF executable, performs the integrity check on the modified TSF
executable and verifies that the check fails.
2.6 Evaluation Activities for Optional SFRs
2.6.1 Identification and Authentication (FIA)
FIA_BMA_EXT.1 Biometric Activation
FIA_BMA_EXT.1
TSS
The evaluator shall confirm that the TSS describes the calls to the platform and verifies they align with platform documentation.
Guidance
The evaluator shall ensure that any configuration details needed to enable the biometric prompt are included in the
guidance documentation.
Tests
Test 1: The evaluator shall initiate a connection and verify that a biometric prompt is presented and accepted before the
connection can proceed. The evaluator shall also verify the connection does not proceed if the biometric is not presented or accepted.
The evaluator shall examine the TSS to verify that it describes how authentication packets are identified and how all
other traffic is blocked until secondary authentication is successful.
Guidance
The evaluator shall examine the operational guidance to verify that it provides instructions to the administrator on how
to configure the secondary HOTP or TOTP
factors and any additional details necessary for filtering all other traffic.
Tests
Test 1: For each included selection the evaluator shall configure the TOE per the operational guidance.
The evaluator shall attempt to connect and verify other traffic is rejected per the filtering rules.
The evaluator shall then provide the selected factor and confirm it is accepted and traffic is no longer blocked.
2.7 Evaluation Activities for Selection-Based SFRs
2.7.1 Cryptographic Support (FCS)
FCS_EAP_EXT.1 EAP-TLS
FCS_EAP_EXT.1
TSS
The evaluator shall verify that the TS describes the use of EAP options for each of the selected peer authentication
mechanisms, that TLS with mutual authentication is used, that the random values are from an appropriate source,
and that the EAP MSK is derived from the TLS master key and is used as the IKEv2 shared key.
Guidance
The evaluator shall verify that the guidance documents describe any configurable features of the EAP or TLS
functionality, including instructions for configuration of the authenticators and registration processes for clients.
Tests
Testing for TLS functionality is in accordance with the TLS package.
For each supported EAP method claimed in FCS_EAP_TLS_EXT.1.1 and for each authentication method claimed in
FCS_EAP_TLS_EXT.1.3, the evaluator shall perform the following tests:
Test 1: The evaluator shall follow AGD guidance to configure the TSF to use the EAP method claimed.
The evaluator shall follow AGD guidance to configure the TSF to use the authentication method claimed and,
for EAP-TTLS, register a client with the appropriate key material required for the authentication method.
The evaluator shall establish an VPN session using a test client with a valid certificate and, for EAP-TTLS,
configured to provide a correct value for the configured authenticator. The evaluator shall observe the the
VPN session is successful.
Test 2: (conditional for EAP-TTLS support): The evaluator shall cause the test client with a valid certificate to send
an invalid authenticator for the claimed authentication method:
For HOTP, replay the HOTP value sent previously,
For TOTP or PSK, modify a byte of the properly constructed value,and observe that the TSF aborts the session
Test 3: The evaluator shall establish a new, valid certificate for a test client using an identifier not
corresponding to a registered user. For EAP-TTLS, the evaluator shall cause the test client using this
certificate to send a correct authenticator value for the registered user. The evaluator shall initiate a
VPN session from the test client to the TSF and observe that the TSF aborts the session.
Test 4: The evaluator shall follow AGD guidance to configure the TSF to use a supported EAP method and register the
user with the key material required for a supported authentication method. The evaluator shall configure a test
client to respond to an IKEv2 exchange with EAP-request, providing valid phase 1 handshake and valid TLS
handshake, but computing the phase 2 shared key using standard (non-EAP) methods. The evaluator shall initiate
a VPN session between the test client and the TSF, and observe that the TSF aborts the session.
The evaluator shall confirm the TSS describes how the TOE complies with the RFC.
The evaluator shall confirm the TSS describes how the HOTP seed is generated and ensure it aligns with FCS_RBG_EXT.1.
The evaluator shall confirm the TSS describes how the HOTP seed is protected and ensure it aligns with the storage requirements of the Base-PP.
The evaluator shall confirm the TSS describes how a new HOTP seed is assigned for each client and how each client is uniquely identified.
The evaluator shall confirm the TSS describes how the HOTP seed is conditioned into an HOTP hash and verify it matches the selection in FIA_HOTP_EXT.1.4.
The evaluator shall confirm the TSS describes how the HOTP hash is truncated and verify it matches the selection in FIA_HOTP_EXT.1.5.
The evaluator shall confirm the TSS describes how the TOE handles multiple incoming invalid requests and verify it provides an anti-hammer mechanism that matches the selections made in FIA_HOTP_EXT.1.6.
The evaluator shall confirm the TSS describes how the TOE handles resynchronization and how it rejects attempts outside of the look-ahead window selected in FIA_TOTP_EXT.1.7.
The evaluator shall confirm the TSS describes how the TOE counter is incremented after each successful authentication.
Guidance
The evaluator shall verify the operational guidance contains all configuration guidance for setting any administrative value that is configurable in the FIA_HOTP_EXT.1 requirements.
Tests
The evaluator shall configure the TOE to use a supported HOTP factor then:
Test 1: Attempt to establish a connection using a factor from a different client. The test passes if the client fails to connect.
Test 2: Attempt multiple connections outside the boundary set in FIA_HOTP_EXT.1.6 and verify the remediation is triggered.
The test passes if remediation is triggered as defined in the selections and assignments.
Test 3: Attempt to use an HOTP that is outside of the value allowed for resynchronization. The test passes if the client fails to connect.
Test 4: Attempt to connect with a valid HOTP, disconnect and attempt to authenticate again with the same HOTP value. The test passes
if the client connects the first time and fails to connect the second time. If the HOTP generated is duplicated the test may be repeated.
FIA_PSK_EXT.1 Pre-Shared Key Composition
FIA_PSK_EXT.1
TSS
The evaluator shall examine the TSS to ensure that it identifies all protocols that allow pre-shared keys.
For each protocol identified by the requirement, the evaluator shall confirm that the TSS states which pre-shared key
selections are supported.
Guidance
The evaluator shall examine the operational guidance to determine that it provides guidance to
administrators on how to configure all selected pre-shared key options if any configuration is required.
Tests
The evaluator shall also perform the following tests for each protocol (or instantiation of a protocol,
if performed by a different implementation on the TOE).
Test 1: For each mechanism selected in FIA_PSK_EXT.1.2, the evaluator shall attempt to establish a connection
and confirm that the connection requires the selected factors in the PSK to establish the connection.
FIA_PSK_EXT.2 Generated Pre-Shared Keys
FIA_PSK_EXT.2
TSS
If "generate" is selected, the evaluator shall confirm that this process uses the RBG specified in FCS_RBG_EXT.1
and the output matches the size selected in FIA_PSK_EXT.2.1.
Guidance
The evaluator shall confirm the operational guidance contains instructions for entering generated pre-shared keys
for each protocol identified in the FIA_PSK_EXT.1.1.
Tests
Test 1: [conditional] If generate was selected the evaluator shall generate a pre-shared key and confirm the output matches
the size selected in FIA_PSK_EXT.2.1.
FIA_PSK_EXT.3 Password-Based Pre-Shared Keys
FIA_PSK_EXT.3
TSS
The evaluator shall examine the TSS to ensure it describes the process by which the bit-based pre-shared keys are used.
Support for length: The evaluator shall check to ensure that the TSS describes the allowable ranges for PSK lengths,
and that at least 64 characters or a length defined by the platform may be specified by the user.
Support for character set: The evaluator shall check to ensure that the TSS describes the allowable character set and that
it contains the characters listed in the SFR.
Support for PBKDF: The evaluator shall examine the TSS to ensure that the use of PBKDF2 is described and that
the key sizes match that described by the ST author.
The evaluator shall check that the TSS describes the method by which the PSK is first encoded and then fed
to the hash algorithm. The settings for the algorithm (padding, blocking, etc.) shall be described, and the evaluator
shall verify that these are supported by the selections in this component as well as the selections concerning the hash function itself.
For the NIST SP 800-132-based conditioning of the PSK, the required evaluation activities will be performed
when doing the evaluation activities for the appropriate requirements (FCS_COP.1/KeyedHash).
The evaluator shall confirm that the minimum length is described.
The ST author shall provide a description in the TSS regarding the salt generation. The evaluator shall confirm
that the salt is generated using an RBG described in FCS_RBG_EXT.1.
[conditional] If password strength meter or password denylist is selected, the evaluator shall examine the TSS to
ensure any password checking functionality provided by the TSF is described and contains details on how the function operates.
Guidance
The evaluator shall confirm the operational guidance contains instructions for entering bit-based pre-shared keys for each
protocol identified in the requirement, or generating a bit-based pre-shared key (or both). The evaluator shall confirm that any
management functions related to pre-shared keys that are performed by the TOE are specified in the operational guidance.
The guidance must specify the allowable characters for pre-shared keys, and that list must include, at minimum, the same
items contained in FIA_PSK_EXT.3.2.
The evaluator shall confirm the operational guidance contains any necessary instructions for enabling and configuring
password checking functionality.
Tests
Support for Password/Passphrase characteristics: In addition to the analysis above, the evaluator shall also perform the following tests on a TOE
configured according to the Operational Guidance:
Test 1: The evaluator shall compose a pre-shared key of at least 64 characters that contains a combination of the allowed characters in accordance
with the FIA_PSK_EXT.1.3 and verify that a successful protocol negotiation can be performed with the key.
Test 2: [conditional]: If the TOE supports pre-shared keys of multiple lengths, the evaluator shall repeat Test 1 using the minimum length and invalid
lengths that are below the minimum length, above the maximum length, null length, empty length, or zero length. The minimum test should
be successful, and the invalid lengths must be rejected by the TOE.
Test 3: [conditional]: If the TOE initiates connections, initiate and establish a remote connection, disconnect from the connection, verify
that the PSK is required when initiating the connection a second time.
Test 4: [conditional]: If the TOE supports a password meter, the evaluator shall enter a password and verify the password checker
responds per the description in the TSS.
Test 5: [conditional]: If the TOE supports a password denylist, the evaluator shall enter a denylisted password and verify that the
password is rejected or flagged as such.
FIA_PSK_EXT.4 HMAC-Based One-Time Password Pre-shared Keys Support
FIA_PSK_EXT.4
TSS
The evaluator shall verify the TSS describes how the HOTP is input into the client and how that value is sent to the server.
The evaluator shall verify the TSS describes how the HOTP is accepted from an incoming connection and how that value is verified,
either by the TOE or by an external authentication server.
Guidance
The evaluator shall verify the operational guidance contains any configuration necessary to enable HOTP.
Tests
Test 1:
The evaluator shall configure the TOE to use a supported HOTP factor, then attempt to establish a connection using that factor.
The evaluator shall verify the client prompts the user for the HOTP before initiating the connection.
The evaluator shall verify the server validates the HOTP or receives confirmation from an authentication server before establishing the channel.
FIA_PSK_EXT.5 Time-Based One-Time Password Pre-shared Keys Support
FIA_PSK_EXT.5
TSS
The evaluator shall verify the TSS describes how the TOTP is input into the client and how that value is sent to the server.
The evaluator shall verify the TSS describes how the TOTP is accepted from an incoming connection and how that value is verified,
either by the TOE or by an external authentication server.
Guidance
The evaluator shall verify the operational guidance contains any configuration necessary to enable TOTP.
Tests
Test 1:
The evaluator shall configure the TOE to use a supported TOTP factor, then attempt to establish a connection using that factor.
The evaluator shall verify the client prompts the user for the TOTP before initiating the connection.
The evaluator shall verify the server validates the TOTP or receives confirmation from an authentication server before establishing the channel.
The evaluator shall confirm the TSS describes how the TOE complies with the RFC.
The evaluator shall confirm the TSS describes how the TOTP seed is generated and ensure it aligns with FCS_RBG_EXT.1.
The evaluator shall confirm the TSS describes how the TOTP seed is protected and ensure it aligns with the storage requirements of the Base-PP.
The evaluator shall confirm the TSS describes how a new TOTP seed is assigned for each client and how each client is uniquely identified.
The evaluator shall confirm the TSS describes how the TOTP seed is conditioned into a TOTP hash and verify it matches the
selection in FIA_TOTP_EXT.1.4.
The evaluator shall confirm the TSS describes how the TOTP hash is truncated and verify it matches the selection in FIA_TOTP_EXT.1.5.
The evaluator shall confirm the TSS describes how the TOE handles multiple incoming requests and verify it provides an anti-hammer
mechanism that matches the selections made in FIA_TOTP_EXT.1.6.
The evaluator shall confirm the TSS describes how the TOE sets a time-step value and verify it matches the selections in the ST.
The evaluator shall confirm the TSS describes how the TOE handles drift and resynchronization and verify it matches the
selections. The evaluator shall ensure the TSS describes how time is kept and whether drift is calculated and recorded.
If drift is recorded, the evaluator shall ensure that the TSS describes how this is done.
Guidance
The evaluator shall verify the operational guidance contains all configuration guidance for setting any administrative value that is
configurable in the FIA_TOTP_EXT.1 requirements.
Tests
The evaluator shall configure the TOE to use a supported TOTP factor then:
Test 1: Attempt to establish a connection using a factor from a different client. The test passes if the client fails to connect.
Test 2: Attempt multiple connections outside the boundary set in FIA_TOTP_EXT.1.6 and verify the remediation is triggered.
The test passes if remediation is triggered as defined in the selections and assignments.
Test 3: Attempt to use a TOTP that is outside of the value allowed for resynchronization. The test passes if the client fails to connect.
Attempt to connect with a valid TOTP, disconnect and attempt to authenticate again with the same TOTP. The test passes if the
client connects the first time and fails to connect the second time. If the TOTP generated is duplicated the test may be repeated.
2.8 Evaluation Activities for Objective SFRs
2.8.1 Security Audit (FAU)
FAU_GEN.1/VPN Audit Data Generation
FAU_GEN.1/VPN
TSS
The evaluator shall examine the TSS to determine that it describes the auditable events and the
component that is responsible for each type of auditable event.
Guidance
The evaluator shall check the operational guidance and ensure that it lists all of the auditable events and
provides a format for audit records. Each audit record format type must be covered, along with a brief
description of each field. The evaluator shall check to make sure that every audit event type mandated by
the VPN Client PP-Module is described and that the description of the fields contains the information
required in FAU_GEN.1.2/VPN, and the additional information specified in the Auditable Events table of
the VPN Client PP-PP-Module.
In particular, the evaluator shall ensure that the operational guidance is clear in relation to the contents
for failed cryptographic events. In the Auditable Events table of the VPN Client PP-Module, information
detailing the cryptographic mode of operation and a name or identifier for the object being encrypted is
required. The evaluator shall ensure that name or identifier is sufficient to allow an administrator
reviewing the audit log to determine the context of the cryptographic operation (for example, performed
during a key negotiation exchange, performed when encrypting data for transit) as well as the non-TOE
endpoint of the connection for cryptographic failures relating to communications with other IT systems.
The evaluator shall also make a determination of the administrative actions that are relevant in the
context of the VPN Client PP-Module. The TOE may contain functionality that is not evaluated in the
context of the VPN Client PP-Module because the functionality is not specified in an SFR. This functionality
may have administrative aspects that are described in the operational guidance. Since such administrative
actions will not be performed in an evaluated configuration of the TOE, the evaluator shall examine the
operational guidance and make a determination of which administrative commands, including
subcommands, scripts, and configuration files, are related to the configuration (including enabling or
disabling) of the mechanisms implemented in the TOE that are necessary to enforce the requirements
specified in the VPN Client PP-Module, which thus form the set of “all administrative actions”. The
evaluator may perform this activity as part of the activities associated with ensuring the AGD_OPE
guidance satisfies the requirements.
For each required auditable event, the evaluator shall examine the operational guidance to determine
that it is clear to the reader where each event is generated (e.g. the TSF may generate its own audit logs
in one location while the platform-provided auditable events are generated elsewhere).
Tests
The evaluator shall test the TOE’s ability to correctly generate audit records by having the TOE generate
audit records in accordance with the EAs associated with the functional requirements in the VPN Client
PP-Module. Additionally, the evaluator shall test that each administrative action applicable in the context
of the VPN Client PP-Module is auditable. When verifying the test results, the evaluator shall ensure the
audit records generated during testing match the format specified in the administrative guide, and that
the fields in each audit record have the proper entries.
Note that the testing here can be accomplished in conjunction with the testing of the security mechanisms
directly. For example, testing performed to ensure that the administrative guidance provided is correct
verifies that AGD_OPE.1 is satisfied and should address the invocation of the administrative actions that
are needed to verify the audit records are generated as expected.
FAU_SEL.1/VPN Selective Audit
FAU_SEL.1/VPN
TSS
There are no TSS EAs for this SFR.
Guidance
The evaluator shall review the administrative guidance to ensure that the guidance itemizes all event
types, as well as describes all attributes that are to be selectable in accordance with the requirement, to
include those attributes listed in the assignment. The administrative guidance shall also contain
instructions on how to set the pre-selection, or how the VPN gateway will configure the client, as well as
explain the syntax (if present) for multi-value pre-selection. The administrative guidance shall also identify
those audit records that are always recorded, regardless of the selection criteria currently being enforced.
Tests
The evaluator shall perform the following tests:
Test 1: For each attribute listed in the requirement, the evaluator shall devise a test to show that selecting
the attribute causes only audit events with that attribute (or those that are always recorded, as identified
in the administrative guidance) to be recorded.
Test 2: [conditional] If the TSF supports specification of more complex audit pre-selection criteria (e.g.,
multiple attributes, logical expressions using attributes) then the evaluator shall devise tests showing that
this capability is correctly implemented. The evaluator shall also, in the test plan, provide a short narrative
justifying the set of tests as representative and sufficient to exercise the capability.
3 Evaluation Activities for SARs
The PP-Module does not define any SARs beyond those defined within the
base-PP to which it must claim conformance.
It is important to note that a TOE that is evaluated against the PP-Module is
inherently evaluated against the Base-PP as well.
The Base-PP includes a number of Evaluation Activities associated with both SFRs and SARs.
Additionally, the PP-Module includes a number of SFR-based Evaluation Activities
that similarly refine the SARs of the Base-PPs.
The evaluation laboratory will evaluate the TOE against the chosen Base-PP
and supplement that evaluation with the necessary SFRs that are taken from the PP-Module.
4 Required Supplementary Information
This Supporting Document has no required supplementary information beyond the ST, operational
guidance, and testing.
Appendix A - References
Identifier
Title
[CC]
Common Criteria for Information Technology Security Evaluation -
