CyberGuard Firewall/VPN Version 6.2.1 Security Target
CyberGuard Corporation
CyberGuard Firewall/VPN Version 6.2.1
Security Target
EAL4 Augmented
CyberGuard Firewall/VPN Version 6.2.1 Security Target
September 30, 2005
Document No. FCC101-002
Revision No. 1.3
CyberGuard Firewall/VPN Version 6.2.1 Security Target
DOCUMENT INTRODUCTION
Prepared By:
CyberGuard Corporation
350 SW 12th Avenue
Deerfield Beach, Florida, 33442
Prepared For:
Common Criteria EAL4+ Certification
This document provides the basis for an evaluation of a specific Target of Evaluation
(TOE), the CyberGuard Firewall/VPN Version 6.2.1. This Security Target (ST) defines a
set of assumptions about the aspects of the environment, a list of threats that the product
intends to counter, a set of security objectives, a set of security requirements and the IT
security functions provided by the TOE which meet the set of requirements.
REVISION HISTORY
Document Number Revision Effective Date
FCC101-000 1.0 July 1, 2005
FCC101-001 1.1 July 1, 2005
FCC101-002 1.2 August 31, 2005
FCC101-003 1.3 September 30, 2005
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
TABLE OF CONTENTS
1. SECURITY TARGET INTRODUCTION................................................................. 1
1.1 Security Target Reference........................................................................................ 1
1.1.1 Security Target Name ..................................................................................... 1
1.1.2 TOE Reference................................................................................................ 1
1.1.3 Security Target Evaluation Status................................................................... 1
1.1.4 Security Target Author.................................................................................... 1
1.1.5 Evaluation Assurance Level............................................................................ 1
1.1.6 Keywords ........................................................................................................ 1
1.2 TOE Overview ......................................................................................................... 1
1.2.1 CyberGuard Firewall/VPN version 6.2.1....................................................... 2
1.2.2 CG Linux Version 6.2.1 Kernel Extensions .................................................. 2
1.2.3 CG Compliance Tested Hardware .................................................................. 3
1.2.4 Authentication Server...................................................................................... 5
1.2.5 Management Station........................................................................................ 5
1.2.6 Security Target Organisation .......................................................................... 6
1.2.7 Common Criteria Conformance...................................................................... 6
1.2.8 Protection Profile Conformance...................................................................... 6
1.3 Conventions ............................................................................................................. 7
1.4 Terminology and Acronyms .................................................................................... 7
2. INTRODUCTION....................................................................................................... 10
2.1 Product Description................................................................................................ 10
2.2 TOE Description .................................................................................................... 11
2.3 Physical Boundary ................................................................................................. 13
2.4 Logical Boundary................................................................................................... 16
2.5 Evaluated Configuration ........................................................................................ 20
2.5.1 Network Security Policy ............................................................................... 21
2.5.2 IP Packet Interface Checking........................................................................ 22
2.5.3 Auditing ........................................................................................................ 22
2.5.4 NAT .............................................................................................................. 22
2.5.5 Proxies........................................................................................................... 22
2.5.6 Administrative Interfaces.............................................................................. 22
2.6 Security Policy Model (SPM)................................................................................ 23
3. SECURITY ENVIRONMENT.................................................................................. 24
3.1 Assumptions........................................................................................................... 24
3.1.1 Connectivity Assumptions ............................................................................ 24
3.1.2 Personnel Assumptions................................................................................. 24
3.1.3 Physical Assumptions ................................................................................... 25
3.2 Threats.................................................................................................................... 25
3.2.1 Threats Addressed by the TOE ..................................................................... 25
3.2.2 Threats to be Addressed by Operational Environment ................................. 26
3.3 Organizational Security Policies............................................................................ 26
4. SECURITY OBJECTIVES ....................................................................................... 27
4.1 Security Objectives for the TOE............................................................................ 27
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
4.2 Security Objectives for the IT Environment.......................................................... 28
5. IT SECURITY REQUIREMENTS........................................................................... 29
5.1 TOE Security Functional Requirements ................................................................ 29
5.1.1 Security Audit (FAU).................................................................................... 31
5.1.2 User Data Protection (FDP) .......................................................................... 34
5.1.3 Identification and Authentication (FIA)........................................................ 39
5.1.4 Security Management (FMT)........................................................................ 41
5.1.5 Protection of the TSF (FPT).......................................................................... 44
5.2 TOE Security Assurance Requirements................................................................. 45
5.2.1 Additional Security Assurance Requirements .............................................. 46
5.3 Security Requirements for the IT Environment..................................................... 46
6. TOE SUMMARY SPECIFICATION....................................................................... 47
6.1 TOE Security Functions......................................................................................... 47
6.2 TOE Security Function Rationale.......................................................................... 54
6.2.1 FAU_GEN.1 ................................................................................................. 55
6.2.2 FAU_SAR.1.................................................................................................. 56
6.2.3 FAU_SAR.3.................................................................................................. 56
6.2.4 FAU_STG.1 .................................................................................................. 57
6.2.5 FAU_STG.4 .................................................................................................. 57
6.2.6 FDP_IFC.1(1) ............................................................................................... 57
6.2.7 FDP_IFC.1(2) ............................................................................................... 57
6.2.8 FDP_IFF.1 (1)............................................................................................... 58
6.2.9 FDP_IFF.1 (2)............................................................................................... 58
6.2.10 FDP_RIP.1 .................................................................................................. 59
6.2.11 FIA_AFL.1.................................................................................................. 59
6.2.12 FIA_ATD.1................................................................................................. 59
6.2.13 FIA_UAU.5................................................................................................. 59
6.2.14 FIA_UID.2 .................................................................................................. 60
6.2.15 FMT_MOF.1 (1) ......................................................................................... 60
6.2.16 FMT_MOF.1 (2) ......................................................................................... 60
6.2.17 FMT_MSA.1(1) .......................................................................................... 61
6.2.18 FMT_MSA.1(2) .......................................................................................... 61
6.2.19 FMT_MSA.1(3) .......................................................................................... 61
6.2.20 FMT_MSA.1(4) .......................................................................................... 61
6.2.21 FMT_MSA.3............................................................................................... 61
6.2.22 FMT_MTD.1 (1)......................................................................................... 62
6.2.23 FMT_MTD.1 (2)......................................................................................... 62
6.2.24 FMT_MTD.2............................................................................................... 62
6.2.25 FMT_SMR.1............................................................................................... 62
6.2.26 FPT_RVM.1................................................................................................ 62
6.2.27 FPT_SEP.1.................................................................................................. 62
6.2.28 FPT_STM.1................................................................................................. 63
6.3 Assurance Measures............................................................................................... 63
7. PROTECTION PROFILE CLAIMS........................................................................ 68
7.1 Protection Profile Reference .................................................................................. 68
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8. RATIONALE .............................................................................................................. 69
8.1 Security Objectives Rationale................................................................................ 69
8.1.1 Rationale for TOE Security Objectives......................................................... 70
8.1.2 Rationale for IT Environment Security Objectives....................................... 74
8.2 Security Requirements Rationale........................................................................... 76
8.2.1 Security Functional Requirements Rationale for the TOE ........................... 76
8.2.2 Security Functional Requirements Rationale for the IT Environment.......... 80
8.2.3 Security Assurance Requirements Rationale ................................................ 80
8.3 TOE Summary Specification Rationale................................................................. 80
8.4 PP Claims Rationale............................................................................................... 80
8.5 Strength of Functions (SOF) Rationale.................................................................. 80
8.5.1 SOF for Password Mechanism...................................................................... 80
8.5.2 SOF for Single Use Authentication Mechanism........................................... 81
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LIST OF FIGURES
Figure 1 - TOE Physical Configuration......................................................................... 14
Figure 2 - TOE Physical Boundary ............................................................................... 16
Figure 3 - Logical Boundaries of the TOE.................................................................... 17
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LIST OF TABLES
Table 1 - Acronym List ................................................................................................. ix
Table 2 - CG Compliance Tested Hardware Models ..................................................... 4
Table 3 - Supported Network Interface Cards................................................................ 4
Table 4 - Functional Components of the TOE ............................................................. 29
Table 5 - Auditable Events (Table 5.2 in TF-MRPP & AP-MRPP)............................ 32
Table 6 - Assurance Requirements of the TOE: EAL4 Augmented ............................ 45
Table 7 - Mappings Between TOE SFRs and TOE Security Functions ...................... 54
Table 8 - TSF Sources of Audit Data........................................................................... 55
Table 9 - Assurance Correspondence........................................................................... 63
Table 10 - Environmental Security Objectives, Assumptions/Threats Mappings ..... 69
Table 11 - Mappings Between IT Security Objectives, and Threats.......................... 70
Table 12 - Mappings Between TOE Security Objectives and TOE SFRs................. 76
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Table 1 - Acronym List
AP-MRPP Final U.S. Department of Defense Application-Level Firewall
Protection Profile for Medium Robustness Environments,
Version 1.0, June 28, 2000
CC Common Criteria for Information Technology Security
Evaluation
(Comprising Parts 1-3, [CC1], [CC2], [CC3])
CC1 Common Criteria for Information Technology Security
Evaluation
Part 1: Introduction and General Model
CCIMB-2004-01-001, Version 2.2, January 2004, Revision 256
CC2 Common Criteria for Information Technology Security
Evaluation
Part 2: Security Functional Requirements
CCIMB-2004-01-002, Version 2.2, January 2004
CC3 Common Criteria for Information Technology Security
Evaluation Part 3: Security Assurance Requirements CCIMB-
2004-01-003, Version 2.2, January 2004, Revision 256
CGIA CyberGuard Firewall Identification and Authentication
CLI Command-Line Interface
DMZ Demilitarized Zone
EAL4 Evaluation Assurance Level 4
GUI Graphical User Interface
HTTP Hyper Text Transfer Protocol
IT Information Technology
LAN Local Area Network
NAT NetWork Address Translation
NIAP National Information Assurance Partnership
PP Protection Profile
RSBAC Rule Set Based Access Control
SAR Security Assurance Requirements
SF Security Function
SFP Security Function Policy
SMTP Simple Mail Transfer Protocol
SOF Strength Of Function
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
ST Security Target
TF-MRPP Final U.S. Department of Defense Traffic-Filter Firewall
Protection Profile for Medium Robustness Environments,
Version 1.4, May 1, 2000
TOE Target of Evaluation
TSC TSF Scope of Control
TSF TOE Security Functions
TSFI TSF Interface
TSP TOE Security Policy
VPN Virtual Private Network
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
CHAPTER 1
1. Security Target Introduction
This Security Target (ST) identifies the Target Of Evaluation (TOE), TOE Common
Criteria (CC) and Protection Profile (PP) conformance claims and describes the
objectives, requirements and rationale for the TOE, which is CyberGuard Firewall/VPN
Version 6.2.1. This Security Target conforms to Common Criteria for Information
Technology Security Evaluation, Version 2.2.
1.1 Security Target Reference
This section provides identifying information for the CyberGuard Firewall/VPN Version
6.2.1 Security Target by defining the Target of Evaluation (TOE).
1.1.1 Security Target Name
CyberGuard Firewall/VPN Version 6.2.1 Security Target, Revision 1.3, September 30,
2005
1.1.2 TOE Reference
CyberGuard Firewall/VPN Version 6.2.1.
1.1.3 Security Target Evaluation Status
This ST is currently under evaluation for Common Criteria EAL4 assurance level
augmented by flaw remediation.
1.1.4 Security Target Author
CyberGuard Corporation.
1.1.5 Evaluation Assurance Level
Assurance claims conform to EAL4 (Evaluation Assurance Level 4) from the Common
Criteria for Information Technology Security Evaluation, Version 2.2. EAL4 is
augmented by ALC_FLR.3, Systematic Flaw Remediation.
1.1.6 Keywords
Traffic-filter, Application-Layer firewall, Application Proxy, Packet filter
1.2 TOE Overview
This Security Target defines the requirements for the CyberGuard Firewall/VPN Version
6.2.1. The evaluated configuration of the TOE shall consist of the following:
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
1. CyberGuard Firewall/VPN version 6.2.1 software
2. CG Linux Version 3.1 Kernel Extensions
3. CG compliance tested hardware
4. Authentication Server
5. Management Station
1.2.1 CyberGuard Firewall/VPN version 6.2.1
The CyberGuard Firewall/VPN version 6.2.1 sits as a barrier between an organization’s
network and external networks. It provides controlled and audited access to services, both
from inside and outside an organization’s network, by inspecting and allowing, denying
and/or redirecting the flow of data (IP packets) that pass through the barrier. The Sub-
Systems of the CG Firewall/VPN version 6.2.1 software that shall be part of the
evaluated TOE are:
o Packet Filter
o FTP Proxy
o Telnet Proxy
o HTTP Proxy
o SMTP Proxy
o NAT
o CyberGuard Identification and Authentication (CGIA) for single-use and multi-
use authentication.
o Rule Set Based Access Control (RSBAC) (access control component)
o Audit Subsystem (accountability component)
o Administration (Graphical user interface for configuration of the TOE)
1.2.2 CG Linux Version 6.2.1 Kernel Extensions
CGLinux Version 3.1 operating system contains enhancements to provide protection
against bypassibility. The components of the CG Linux version 6.2.1 operating system,
referred to as the ‘Kernel Extensions Subsystem’ that shall be part of the evaluated TOE
are the enhancements that help the operating system achieve the following:
o Kernel residual data protection
o Non-bypassibility
o Process Control
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
1.2.3 CG Compliance Tested Hardware1
The ‘CyberGuard Firewall/VPN version 6.2.1’ software and the ‘CGLinux Version 3.1’
operating system are installed and delivered on an intel processor based CG Compliance
Tested Hardware. Currently the following configurations of the CG Compliance Tested
Hardware, also referred to as the ‘CyberGuard Firewall/VPN Appliance’ through out this
document, are available:
1000 Series is available as a compact 1U size unit and is designed for use in
mid-size, growing network environments.
3000 Series is available as a 1U, 2U, and 5U size unit and is designed to
provide powerful protection for enterprises, data centres and
service providers.
5000 Series is available as a 5U size unit and is designed to provide
comprehensive security for high-bandwidth data centres, web
hosting and ISP/ASP markets.
7000 Series is available as a 3U size unit and is designed to provide
comprehensive security for high-bandwidth data centres, web
hosting and ISP/ASP markets.
Where: ‘U’ is the form factor depicting the unit slots occupied on the ‘Rack
Mount’. For e.g., Form Factor=1U indicates that the ‘CG Firewall
‘CyberGuard Firewall/VPN Appliance’ occupies 1 slot on the rack
mount; Form Factor=5U indicates that the ‘CyberGuard
Firewall/VPN Appliance’ occupies 5 slots on the rack mount
Detals of the various configurations of the ‘CG Compliance Tested Hardware’ are
depicted in Table 2 - Table 3 - below :
1
The terms ‘CG Compliance Tested Hardware’ and ‘CyberGuard Firewall/VPN Appliance[s]’ are
interchangeably used throughout this document.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Table 2 - CG Compliance Tested Hardware Models
Model
On-
Board
NIC
Card
Network
Interface
Cards (NIC)
Maximum
Interfaces
Expansion
Slots
CPU Memory RAID Power Supply
1150 Yes See Table 3 -
below
3 None 1 x Intel P4 2.4
GHz.
128 MB N 1
1250 Yes See Table 3 -
below
6 None 1 x Intel P4 2.8
GHz.
256 MB N 1
3100 Yes See Table 3 -
below
8 None 1 x Intel P4 Xeon
2.4 GHz.
512 MB N 1
3400 Yes See Table 3 -
below
20 4 1 x Intel P4 Xeon
3.06 GHz.
512 MB N 1 Standard; 2nd
Optional
3600 Yes See Table 3 -
below
22 3 1 x Intel P4 Xeon
3.06 GHz.
1 GB Y 2 Standard; 3rd
Optional
5100 Yes See Table 3 -
below
22 1 2 x Intel P4 Xeon
3.06 GHz.
2GB Y 2 Standard; 3rd
Optional
7100 Yes See Table
Below
38 3 4 x AMD Opteron
2.2 GHz
4 GB Y Redundant
Power Supply
Table 3 - Supported Network Interface Cards
CG COMPLIANCE TESTED HARDWARE MODELS
1150 1250 3100 3400 3600 5100 7100
NIC
CHIPSET
Silicon 6-
Port
Copper
Silicom
Option Standard Standard Standard Standard Standard Standard Intel 882546
4-Port
Fiber Intel
No No Option Option Option Option Option Intel 882546
PRO
1000MT
Dual
Copper
Option Option Standard Option Option Option Option Intel 882546
Intel PRO
1000MF
Dual Fiber
Option Option Option Option Option Standard Option Intel 882546
Intel
PRO100M
Single
10/100
Standard Option Option Option Option Option No Intel 82551
N
ETWORK
I
NTERFACE
CARDS
(NIC)
Interphase
554
Option Option Option Option Option Option No Intel 21143
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
The CyberGuard Firewall/VPN Appliance, as depicted in Table 2 - Table 3 - above, come
in various models. All the models share a very similar hardware architecture, use Intel
CPUs as their main processor and have a similar packet flow. All the models run the
CGLinux 3.1 operating system and the CyberGuard Firewall/VPN 6.2.1 with the same
core features and therefore perform the same security functions and implement the same
interfaces in the same way. The onboard NIC cards that are available on all the models
are used to connect the appliance to an authentication server, the management station
and/or the Internal Interfaces. These onboard NIC cards are functionally equivalent to the
NIC cards available on the ‘CG Compliance tested Hardware Models’ mentioned in
Table 2 - Table 3 - above, and have either Intel 82551 or Intel 882546 chipsets. The on-
board NIC card on the 7100 uses a Broadcom BCM570x chipset2
. The CyberGuard
compliance tested hardware also has the provision for external NIC cards (mounted on
the standard PCI slots in the appliance). All the NIC cards as depicted in Table 3 - above,
have same/similar chipset and can be interchangeably3
mounted/installed on any model
of the appliance. As such, any of the above mentioned 6 NIC cards, installed on anyone
of the above mentioned CG compliance tested hardware models, can be used towards
meeting the security function requirements associated with the INTERCEPT security
function defined in the TOE Summary Section (section 6. ) of this document.
All the other hardware components (i.e., with the exception of the ‘Network Interface
Cards’) listed in the tables above are not security relevant as they do not provide any
internal/external interfaces that could be exploited by individuals with hostile or
malicious intent.
1.2.4 Authentication Server
The single use Authentication Server is the ‘RSA Authentication Manager Version 6.0’
that interacts with the ‘CyberGuard Firewall/VPN version 6.2.1 ’ via the RADIUS
authenticator plug-in module. The RADIUS authenticator plug-in is a dynamically linked
library that extends the capabilities of the authentication subsystem by authenticating
users via the external ‘RSA Authentication Manager Version 6.0’. In the evaluated
version of the TOE the ‘Authentication Server’ shall be dedicated for single use
authentication of users and shall not be connected/interfaced to any other network or
product.
1.2.5 Management Station
A dedicated ‘Management Station’ running ‘Microsoft Internet Explorer’ version 6.0 or
above shall allow an ‘authorized administrator’ to manage/configure the ‘CyberGuard
Firewall/VPN version 6.2.1’. The ‘Management Station’ interacts/interfaces with the
2
The Broadcom BCM570x chipset is functionally same/similar to the Intel 82551 and Intel 882546
chipsets.
3
The 4-Prot Fiber Intel NIC card cannot be mounted on the 1150 and 1250 because of mechanical
limitations.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
‘Management Software’, a part of the ‘CyberGuard Firewall/VPN version 6.2.1’ residing
on the CG Compliance tested hardware, while allowing only an ‘authorized
administrator’ to manage/configure the TOE.
1.2.6 Security Target Organisation
Chapter 1. of this ST provides introductory and identifying information for the TOE.
Chapter 2. describes the TOE and provides some guidance on its use.
Chapter 3. provides a security environment description in terms of assumptions, threats
and organisational security policies.
Chapter 4. identifies the security objectives of the TOE and of the Information
Technology (IT) environment.
Chapter 5. provides the TOE security functional requirements, as well as requirements
on the IT environment.
Chapter 6. is the TOE Summary Specification, a description of the functions provided
by the CyberGuard Firewall/VPN Version 6.2.1 to satisfy the security
functional and assurance requirements.
Chapter 7. identifies claims of conformance to registered Protection Profiles (PP).
Chapter 8. provides a rationale for the security objectives, requirements, and TOE
summary specification and PP claims.
1.2.7 Common Criteria Conformance
The CyberGuard Firewall/VPN Version 6.2.1 is conformant with the Common Criteria
(CC) Version 2.2, functional requirements (Part 2) and assurance requirements (Part 3)
conformant for EAL4 augmented by ALC_FLR.3, Systematic Flaw Remediation.
1.2.8 Protection Profile Conformance
The CyberGuard Firewall/VPN Version 6.2.1 has been modeled4
on the following two
Protection Profiles:
A. Traffic-Filter Firewall Protection Profile for Medium Robustness
Environments, Version 1.4, May 1, 2000
B. Application-Level Firewall Protection Profile for Medium Robustness
Environments, Version 1.0, June 28, 2000
4
Albeit the CyberGuard Firewall/VPN version 6.2.1 has been modeled on the TF-MRPP & AP-MRPP it
does not claim conformance to either.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
1.3 Conventions
The notation, formatting, and conventions used in this Security Target are consistent with
those used in version 2.2 of the Common Criteria (CC). Selected presentation choices are
discussed here to aid the Security Target user. The CC allows several operations to be
performed on functional requirements; refinement, selection, assignment, and iteration
are defined in paragraph 2.1.4 of Part 2 of the CC. Some or all of these operations have
been used in this Security Target.
o The refinement operation is used to add detail to a requirement, and thus further
restricts a requirement. Refinement of security requirements is denoted by bold
text. For example, refinement.
o The selection operation is used to select one or more options provided by the CC
in stating a requirement. Selections are denoted by underlined italicized text. For
example, allocation of the resource to all objects.
o The assignment operation is used to assign a specific value to an unspecified
parameter, such as the length of a password. Assignment is indicated by showing
the value in square brackets, [ assignment_value ]. For an example, [8 characters].
o The iteration operation is used when a component is repeated with varying
operations. Iteration is denoted by showing the iteration number in parenthesis
following the component identifier, (iteration_number). For example, see
FDP_IFC in this Security Target.
Differences in the text used to describe the functional components within the two PPs this
security target claims conformance to have been described in the ‘Protection Profile
Claims’ chapter.
This Security Target also utilizes bolding and underlining to mark the chapter and section
headings and captions. Regular italics have been used to identify unique references in the
ST, such as the reference to the Protection Profiles to which the TOE conforms.
1.4 Terminology and Acronyms
For a list of Acronyms, see Table 1 - Acronyms List.
This section contains the terminology that has been used throughout the ST. Additional
definitions are available in the following protection profiles that were used as a model for
the construction of this ST.
A. Traffic-Filter Firewall Protection Profile for Medium Robustness
Environments, Version 1.4, May 1, 2000
B. Application-Level Firewall Protection Profile for Medium Robustness
Environments, Version 1.0, June 28, 2000
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Firewall: The many forms of a bastion host (one that does not automatically allow traffic
to flow through it) which generally protect the boundary of the network, working as a
gatekeeper, and have built in features to either perform packet filtering or application
proxy or a combination of both on the network traffic.
Network Address Translation (NAT): This is a method by which real internal (protected)
network address are translated to fake internal addresses in and out of a network in order
to hide the internal network topology.
NAT: Network Address Translation: An Internet standard that is used where two
networks with incompatible addressing schemes meet. It allows a Local Area Network
(LAN) to use one set of IP addresses for ‘Internal Traffic’ and a second set of addresses
for ‘External Traffic thereby facilitating internal IP address hiding and reuse of IP
addresses by internal networks.
Virtual Private Network (VPN): This is a method of encapsulating data in a tunnel
using cryptographic algorithms in order to protect data from discovery while en route to
and from its source and destination.
Packet Filtering (also called Stateful Inspection) This is a general form of various
schemes of inspection of each and every packet to and from a protected network to check
its integrity and making decisions on whether to permit or deny that packet from
traversing the protected network.
FTP: File Transfer Protocol: A network application protocol that facilitates transfer of
files between two connected computers.
Telnet: A network application protocol that facilitates remote connection to and
accessing remote computers.
HTTP: Hyper Text Transfer Protocol: A network application protocol that facilitates
transfer of hypertext documents and related resources across the Internet from servers to
clients.
SMTP: Simple Mail Transfer Protocol: A store-and-forward protocol used by mail
transfer agents to transfer electronic mail messages.
Application Proxy: These are security hardened versions of corresponding network
application services such as HTTP, SMTP, FTP, and Telnet that work as agents on a
firewall and mediate the connection between a client and a server on the protected side,
thereby protecting the server from direct access and attack by clients on the unprotected
side of the network.
Demilitarized Zone (DMZ): This is a protected segment of the internal network in
which the access to the unprotected side is allowed, however, the ability to connect to the
internal network is disabled or limited and controlled. The purpose of a DMZ is to allow
access to unprotected network, without compromising the integrity of the protected side.
Example, when hosting an external web site for an organization, a DMZ segment of the
network allows free access to the web site by clients on the external network, yet
eliminates possibility of those clients gaining access to internal (protected segments) of
the organization’s network.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Single-use Authentication Mechanism: This is a method of authentication in which a
random and one time token is generated for the user to authenticate itself. The one-time
use of the token for authentication purposes eliminates the possibility of reuse of the
authentication data if intercepted and captured.
Multi-use Authentication Mechanism: This is a method of authentication in which a
static password is assigned to the user to authenticate with each time authentication is
required.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
CHAPTER 2
2. Introduction
This section provides the context for the TOE evaluation by identifying the product, its
type and features, defining the scope of the TOE and TOE boundaries, both physical and
logical, and describing the evaluated configuration.
2.1 Product Description
CyberGuard Firewall/VPN Product represents integrated firewall appliances that utilize
hybrid firewall architecture, consisting of packet filtering and application proxy
techniques to inspect, control and protect the flow of network traffic in and out of an
organization’s network and to protect the integrity of organizations’ internal networks.
CyberGuard Firewall/VPN Product further combines this functionality with Virtual
Private Network capability in order to protect network traffic that goes in and out of an
organizations’ network while en route to and from its source and destination.
CyberGuard Firewall/VPN Product also provides Network Address Translation (NAT)
facilities in order to hide the internal network addresses of an organization. The product
also has a provision for various network service application proxies that break the direct
connection between clients and servers in order to protect an organization’s servers and
where applicable identify and authenticate users before allowing requested services to be
provided to them.
Split DNS capability of the CyberGuard Firewall/VPN Product allows the organizations’
domain name servers to be split between servicing internal and external requests for
name/IP translations and is aimed at controlling communication between external and
internal nameservers under strict rules so as to avoid allowing direct access to internal
nameservers and thereby exposing internal network addresses or allowing the internal
nameservers to be directly contacted or exploited.
Passport capabilities of the product allows known remote users access to an
organization’s internal network resources by identifying and authenticating those users
and providing a fine grained level of control over the time and method of access and
resources to be accessed by such users.
In identifying and authenticating users, CyberGuard Firewall/VPN Product utilizes a
multi-faceted central authentication mechanism that allows various methods of
authentication such as password or single-use token authentication to be assigned to
administrators and network users.
A User Graphical Interface (GUI), also referred as the ‘Management Software’
throughout this document, is used to manage the ‘CyberGuard Firewall/VPN Product’.
The firewall may be managed locally or remotely. The product has full auditing and
alerting capabilities with additional tools designed for filtering, reviewing, and inspecting
specific audit records, as well as full backup and restore capabilities and audit data
relocation to secondary storage devices in a secure manner.
10
CyberGuard Firewall/VPN Version 6.2.1 Security Target
The packet-filtering engine inspects and filters network traffic based on a configured
security policy and corresponding rule set. The packet filtering engine contains a VPN
component that inspects VPN protected traffic on arrival and before handing it off to the
packet filter for access control and further processing and applies VPN protection to the
inspected and permitted traffic after packet filter has completed its processing and before
handing it off to the network interface.
The NAT facility translates all internal addresses on out-bound traffic based on a
configured rule set to fake addresses before traffic leaves the firewall and translates in-
bound traffic to their corresponding real addresses on arrival.
The application proxies protect internal servers from exploitation by breaking the direct
connection between clients and servers and mediating the traffic between them, and
where applicable:
o hide the internal addresses of real servers by rewriting the headers of messages on
out-bound traffic and removing references to internal addresses;
o identify and authenticate users of network services before providing requested
service to them;
o Perform protocol filtering to ensure adherence to established protocol standards.
The Rule Set Based Access Control component of the CyberGuard Firewall/VPN Product
is an internal access control mechanism that protects the various Sub-Systems of the
firewall against unauthorized access and provides domain separation for the firewall’s
internal processes, based on a configured rule set.
The CyberGuard Firewall/VPN Product is available in High Availability (HA)
configurations and further contains features that cover version tracking and change
control features.
The CG Linux Version 6.2.1 has been enhanced to allow residual data protection in
memory utilized for packet processing. This is done by zeroizing the memory bits before
reuse of the memory for additional packets and also by allowing the ‘CyberGuard
Firewall/VPN Product’ kernel modules (Packet Filter, NAT driver, and VPNguard) to
break into and bind to the network layer and control flow of traffic at the lowest possible
layer of the OSI model.
The CyberGuard Firewall Product can also have up to a maximum of thirty eight (38)
physical interface (network) connections.
2.2 TOE Description
The TOE is a subset of full functionality that the ‘CyberGuard Product’ (described above,
under ‘Section 2.1 Product Description ’) provides. The TOE claims conformance to the
TF-MRPP and AP-MRPP protection profiles as it contains Sub-Systems that are directly
involved in enforcing the security functional requirements mandated by the two
protection profiles
A brief TOE description is provided above, under ‘Section 1.2 - TOE Overview’. It
consists of CyberGuard Firewall/VPN version 6.2.1 software, CGLinux Version 3.1
11
CyberGuard Firewall/VPN Version 6.2.1 Security Target
kernel enhancements, Authentication Server, Management Station and the CG
compliance tested hardware (CyberGuard Firewall/VPN Appliances). Together these
components implement the requirements of the ‘Final U.S. Department of Defense
Traffic-Filter Firewall Protection Profile for Medium Robustness Environments (TF-
MRPP)’ and ‘Final U.S. Department of Defense Application-level Firewall Protection
Profile for Medium Robustness environments (AP-MRPP)’ upon which the CyberGuard
Firewall/VPN version 6.2.1 is modeled.
The ‘CyberGuard Firewall/VPN version 6.2.1’ sits as a barrier between an
organization’s network and external networks. It provides controlled and audited access
to services, both from inside and outside an organization’s network, by inspecting and
allowing, denying and/or redirecting the flow of data (IP packets) that pass through the
barrier. The Sub-Systems of the CG Firewall/VPN version 6.2.1 software that are part of
the evaluated TOE are the Packet Filter engine, NAT, FTP Proxy, Telnet Proxy, HTTP
Proxy, SMTP Proxy, CGIA ( used for single-use and multi-use authentication), Rule Set
Based Access Control (RSBAC) (access control component), Audit subsystem
(accountability component), and the Administration (Graphical user interface for
configuration of the TOE).
The ‘CGLinux Version 3.1’ operating system contains enhancements to provide
protection against bypassibility. These enhancements also referred to as as the ‘Kernel
Extension’ subsystem are part of the evaluated TOE that help the operating system
achieve kernel residual data protection, Non-bypassibility, and Process Control.
The single use ‘Authentication Server’ is the ‘RSA Authentication Manager version 6.0’
that interacts with the ‘CyberGuard Firewall/VPN version 6.2.1’ via the RADIUS
authenticator plug-in module. The RADIUS authenticator plug-in is a dynamically linked
library that extends the capabilities of the authentication subsystem by authenticating
users via the external ‘RSA Authentication Manager Version 6.0’. In the evaluated
version of the TOE the ‘Authentication Server’ shall be dedicated for single use
authentication of users and shall not be connected/interfaced to any other network or
product.
A dedicated ‘Management Station’ running ‘Microsoft Internet Explorer’ version 6.0 or
above shall allow an ‘authorized administrator’ to manage/configure the ‘CyberGuard
Firewall/VPN version 6.2.1’. The ‘Management Station’ interacts/interfaces with the
‘Management Software’, a part of the ‘CyberGuard Firewall/VPN version 6.2.1’ residing
on the CG Compliance tested hardware, while allowing only an ‘authorized
administrator’ to manage/configure the TOE.
The evaluated ‘CyberGuard Firewall/VPN Appliances (CG compliance tested
hardware)’ have the ‘CyberGuard Firewall/VPN version 6.2.1’ software and the
‘CGLinux Version 3.1’ operating system installed and delivered on them and are based on
commodity ‘Intel IA-32 Architecture’. The ‘CyberGuard Firewall/VPN Appliances’
consist of any of the configurations mentioned in ‘Section 1.2.3 - CG Compliance Tested
Hardware’, with a minimum processor speed of 133 MHz. These appliances run on the
following single or multi, Intel family processors:
A) Pentium III
12
CyberGuard Firewall/VPN Version 6.2.1 Security Target
B) Pentium III Xeon
C) Pentium 4
D) Pentium 4 Xeon
A ‘Management Station’, running Microsoft Internet Explorer, version 6.0 or above, is
directly (or via an isolated or protected network) attached to the ‘CyberGuard
Firewall/VPN Appliances’. In addition, in the evaluated configuration, the single-use
‘Authentication Server’ is also either directly or through an isolated network connected to
the ‘CyberGuard Firewall/VPN Appliance’.
The TOE safeguards information held on internal networks, by controlling the access of
external users and protecting the integrity, availability, and authentication data of the
internal network. Additional network interfaces (up to 38) provide further internal/
external network connections.
Security features within the scope of the TOE include:
A) Connection level Access Control for IP packets (e.g. permit/deny source &
destination addresses or ports; divert IP packets to a proxy process [FTP,
TELNET, HTTP, SMTP]).
B) Network Address Translation [NAT] for hiding the internal network
addresses of an organization.
C) Single-use and multi-use authentication mechanisms.
D) Rule Set Based Access Control facility for role enforcement and domain
separation.
E) Accounting, auditing and statistics of firewall traffic and security related
events.
F) Enhancements for and extensions to the CGLinux operating system
modules to ensure that TOE security functions are non-bypassable and
resistant to modification.
VPN, Remote Administration capabilities, Passport facility, SDNS, other proxies, version
tracking features, and High Availability (HA) configurations, have not been included in
the TOE, as their functionality does not have any bearing on claims of conformance to
the PPs.
2.3 Physical Boundary
The TOE as shown in Figure 1 - below, includes a management station (where its
administrative interface is installed), an authentication server (where its single-use
authentication server is installed), the CG Compliance Tested Hardware, CGLinux
version 3.1 kernel enhancements (Kernel Extensions) and CyberGuard Firewall/VPN
version 6.2.1 software. The management station, along with the single-use authentication
server, must both be located in a physically secure location and be directly connected to
the CG Compliance Tested Hardware or alternatively, installed on a protected subnet,
13
CyberGuard Firewall/VPN Version 6.2.1 Security Target
such as a DMZ network configuration. The CGLinux version 3.1 and CyberGuard
Firewall/VPN version 6.2.1 software are installed on the CG Compliance Tested
Hardware.
CGCompliance
Tested Hardware
CGLinux Ver.
3.1
TOE
Authentication
Server
Management
Station
Interface
Internal
Firewall/VPN 6.2.1
CyberGuard
(1 or more)
External Network
(1 or more)
Internal Network
Internal
Interface
Figure 1 - TOE Physical Configuration
The TOE’s physical boundary therefore, consists of the CG Compliance Tested Hardware
on which the CGLinux version 3.1 and the CyberGuard Firewall/VPN version 6.2.1
software are installed, the management station where its administrative interface is
installed and an authentication server where its single-use authentication server is
installed . Within its physical boundary the TOE contains the following software sub-
systems:
A) Administration: The Administration subsystem has user interfaces for
configuring the security policy, for controlling the security functions, and
for processing audit information. These interfaces consist of the graphical
user interfaces (GUI).
B) NAT: The ‘Network Address Translation’ component translates all
internal addresses on out-bound traffic based on a configured rule set to
fake addresses before traffic leaves the firewall and translates in-bound
traffic to their corresponding real addresses on arrival. This facilities in
hiding the internal network addresses of an organization
C) Packet Filter: The packet Filter component filters packets according to the
network security policy. Depending on addresses and rules present a
packet can be rejected (dropped), passed through, or passed to an
appropriate application proxy.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
D) RSBAC: The RSBAC component provides access control mechanisms for
the TOE in terms of role enforcement and to create a separate domain of
execution for the TOE and TOE security functions.
E) Proxies (FTP Proxy, Telnet Proxy, HTTP, SMTP): The TOE provides
proxies for FTP, TELNET, HTTP and SMTP proxies that enforce
correctness of the protocols, limitations on access, and user identification
and authentication for the protocols.
F) Audit: The Audit component provides for secure storage and review of
audit records generated by all of the Sub-Systems of the TOE. Audit
records can be viewed, searched, sorted, dumped, and deleted. Audit
record are time stamped based on time that is calculated and maintained
by the TOE, using an initial time obtained from the hardware platform’s
battery backed up clock.
G) Kernel Extensions: The TOE includes enhancements for several kernel
functions to meet the requirements of the Protection Profiles. Functions
modified are the IP packet input and output handling functions to allow
the packet filter to bind to network interfaces, and the memory release
functions to guard against residual data in memory utilized for processing
packets. These enhancements ensure that the Packet Filter engine
processes all packets, that the TOE security mechanisms are not
bypassable and that all memory is cleared upon release to the system.
Extensions to the kernel include RSBAC, which controls access control
routines by restricting all access to security enforcing functions of the
TOE to authorized administrators only and providing internal access
control and domain separation for the TOE.
H) CyberGuard Firewall Identification and Authentication (CGIA): CGIA
provides the authentication functions that are used by the TOE to allow
access to proxies, and to administration using either a password
mechanism or a single-use, token based method of authentication.
I) Single use Authentication Server5
J) Management Station6
with the Microsoft Internet Explorer version 6.0 or
above
The physical boundary of the TOE’s software Sub-Systems is outlined in Figure 2 -
below:
5
The ‘RSA Authentication Manager 6.0’ is the ‘Single use Authentication Server’. The terms ‘Single use
Authentication Server’, ‘Authentication Server’ and ‘RSA Authentication Manager 6.0’ have been
interchangeably used throughout this document.
6
No other software, besides the Internet Explorer 6.0 or above, runs on the Management station. The sole
purpose of the Management Station is to provide a browser (i.e., Internet Explorer 6.0 or above) for the
GUI to run.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Figure 2 - TOE Physical Boundary
CyberGuard
Firewall/VPN
Version 6.2.1
o Admin Interface
(GUI)
o CGIA
o Proxies (FTP,
Telnet, HTTP &
SMTP)
o Audit
o RSBAC
o Packet Filter
o NAT
o Kernel
Enhancements
Management
Station (Microsoft
IE 6.0 or above)
Authentication
Server (Single Use
Authenticator)
Protected Internal Networks External Networks
CGLinux Version 3.1
CG Compliance Tested Hardware
2.4 Logical Boundary
As shown below in Figure 3 -, part of the TOE is tightly coupled with the CGLinux
operating system upon which it is installed. In general, the TOE is the application
software, however portions of the TOE are hooked into or modify portions of the
CGLinux kernel, to ensure that all network traffic is passed through the TOE Sub-
Systems and all Protection Profile requirements are met. The TOE also includes the CG
Compliance tested hardware, the management station and the authenticator server.
16
CyberGuard Firewall/VPN Version 6.2.1 Security Target
17
NAT
Non-Security Enforcing
TOE Subsystems
Security Enforcing TOE
Subsystems
LEGEND
Microsoft IE
6.0 or above
Single Use
Authenticator
CGLinux Ver. 3.1
Admin I/F
GUI
Proxies
CGIA
RSBAC
Audit
Packet
Filter
Kernel Space
User Space
OS Code
Kernel Extensions
Figure 3 - Logical Boundaries of the TOE
The Administrative Interfaces, Proxies, CGIA, and Audit subsystems are application
software. The Packet Filter subsyetm hooks into the CGLinux IP packet handling
functions to ensure that all packets are filtered and translated through the TOE. RSBAC
subsystem is a kernel extension that provides access control, role enforcement, security,
and domain separation for the TOE. The TOE also modifies the CGLinux kernel routines
for releasing memory to provide protection for residual information in that memory.
The ‘Management Station GUI’ utilizes Microsoft Internet Explorer (IE) revision 6.0 or
above as a front-end to display the configurable features of the TOE so that the site
security policy can be implemented. The GUI features a modular design and although it
CyberGuard Firewall/VPN Version 6.2.1 Security Target
presents many default secure options, it also enables the administrator to define objects
and utilize those objects in defining the rule set that will represent the security policy for
the TOE.
This makes the management software and its configuration options more flexible to allow
all sorts of configuration options to be implemented and configured. These features
provide the administrator with finer grain of control and details in defining security
policy of the site. The GUI allows only the authorized administrator to log on and to
configure the security features of the TOE. There is no concept of users on the TOE,
other than the administrator user.
The ‘CyberGuard Identification and Authentication (CGIA)’ subsystem is a central set of
libraries and associated interfaces that are utilized by all Sub-Systems of the product that
require identification and authentication services. The CGIA facilitates Multiple
Authentication Mechanisms for various applications/proxies.
Using the multiple methods of authentication, the administrator can assign single use
authentication method to users of network services (such as Telnet and FTP) in order to
identify and authenticate such users. The single use authenticator server that is part of the
TOE is the ‘RSA Authentication Manager 6.0’.
The configured method is enforced per user. Safeguards have also been put into place so
that if a user is unsuccessful in completing both the identification and authentication
phases within a configurable number of attempts, and within a configurable length of
time, for the TOE to take action by blacklisting such users until the administrator can
review and access the reason for the failures and restore the user. This guards against
attempts at guessing valid user Ids or passwords.
The ‘Network Address Translation (NAT)’ subsystem is used to hide internal network
addresses from external hosts, while allowing network services to be routed through the
firewall. Local IP addresses are translated to one of the firewall’s registered external IP
interface addresses so that, from outside, all traffic appears to be originating from or
terminating at the firewall. This is accomplished by rewriting the packet headers flowing
through the firewall.
The ‘Packet Filter’ subsystem is responsible for inspecting each and every packet that
reaches the organization’s network and using its knowledge of organizational security
policy, translated to its rule set makes critical decisions on whether to allow the traffic to
go through, deny the traffic or if configured for proxy service to hand off the packet to an
appropriate proxy service on the TOE for further processing of the request.
The packet filter has a variety of security checks on packets before making any decisions
on the status of the packet. These include defenses for variety of mal formed or invalid
packets. If the rule set explicitly mandates dropping a specific type of traffic, it will be
likewise dropped. If the rule set permits a certain type of traffic to enter the internal
network, the packet filter engine will allow the traffic. When a packet arrives that is
destined for a network service and such services has been configured for proxy services,
the packet filter will pass the packet to the appropriate proxy to validate the users and
further process the packet and return the appropriate responses in a secure manner.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
The FTP, Telnet, HTTP and SMTP proxies are security-hardened versions of the
corresponding network services that operate on the TOE. On one hand, the proxy
communicates with the packet filter to receive requests for specific services for which it
is responsible and on the other, the proxy service establishes connections between the
client and the real server on the protected side of the network, and intercepts all requests
from the client, delivers such request to the real server and in turn retrieves responses
from the server and delivers them back to the client. This processing takes place in a
seamless fashion, in which the client is unaware of the proxy service breaking its direct
connection to the real server. The purpose of the proxy is to identify valid users, protect
the servers from exploitation, and hide their real addresses in order to protect them from
direct attack by the rogue clients.
The ‘Audit’ subsystem is a central auditing mechanism in which all Sub-Systems of the
TOE collect security relevant information and drop them into a funnel that feeds to the
audit subsystem, which will process and then post them to the audit trail file with real-
time time stamps to signify when the event occurred. The audit subsystem is configurable
and is equipped with accompanying tools for filtering, reviewing, searching and sorting
through the audit records based on a variety of criteria, including IP address ranges, date
and time ranges, and specific event types.
The audit trail is designed to provide accountability of actions taken when configuring
the security policy and to aid the administrator in recognizing suspicious activities and
setting alert conditions to be delivered in a variety of ways. The audit subsystem has been
configured to shut down network traffic in the event the audit space is exhausted, in order
to eliminate the possibility of suspicious activities taking place on the system while no
accountability exist. Once the administrator accesses the situation and frees up space by
moving the existing audit data to an appropriate medium, network traffic and auditing
will once again resume.
The ‘Kernel Extensions’ subsystem includes enhancements for several kernel functions
that help meet the requirements of the Protection Profiles. Functions modified are the IP
packet input and output handling functions to allow the packet filter to bind to network
interfaces, and the memory release functions to guard against residual data in memory
utilized for processing packets. These enhancements ensure that the Packet Filter engine
processes all packets, that the TOE security mechanisms are not bypassable and that all
memory is cleared upon release to the system.
The ‘RSBAC’ subsystem is used to provide internal access control to the various Sub-
Systems and resources of the TOE. The RSBAC has a variety of functionality such as
mandatory and discretionary access control and role enforcement that essentially work to
separate administrative access to the TOE resources from non-administrative access.
RSBAC checks multiple credentials for users that attempt to access the internal Sub-
Systems or resources of the TOE and only when all the related credentials are in place
and match its rule set it will allow access to the resource to be made. The RSBAC
database of users is aware of every user’s assigned role in addition to the set of
commands associated with the role that a user can execute. In this fashion, if and when a
user (non administrative user such as a network FTP or Telnet user for example) attempt
to access the TOE’s internal resources or objects, such access will not be granted.
19
CyberGuard Firewall/VPN Version 6.2.1 Security Target
2.5 Evaluated Configuration
The evaluated configuration of the CyberGuard Firewall/VPN Version 6.2.1 software is
supplied on CG Compliance Tested Hardware (please refer to Section 1.2.3 above) that
has passed a verification performed according to CyberGuard’s platform compliance and
certification process. It consists of the Intel platform (min speed 133 MHz) running
CyberGuard CGLinux Version 3.1 and CyberGuard Firewall/VPN Version 6.2.1,
equipped with both on-board7
and PCI Network Interface Cards (NIC), a disk storage
device, memory, and a CDRom device. The evaluated configuration shall also consist of
the Management Station containing the Microsoft Internet Explorer 6.0 or above and the
‘RSA Authentication Manager 6.0’ for single use authentication.
The evaluated configuration requires configuration of some specific values of features,
which have been outlined below. More details on these security considerations can be
found in the product’s guidance documentation:
o The prospective customer must define, document, and follow a network security
policy that is appropriate for their site. However, the following security
considerations must also be implemented to be complaint with the evaluated
configuration of TOE:
o The TOE must be secured so that only authorized personnel have physical access
to the TOE.
o The minimum password length for users must be set at eight and the password
must consist of a combination of alphanumeric and special characters. These
combinations will place the password name space well beyond the range that
might make the passwords guessable within a reasonable amount of time.
o It is recommended that configuration and management of the TOE be designated
to one administrator who has all administrative roles assigned to them.
o The TOE must not be configured to allow remote administration, since remote
administration is not included in the scope of this evaluation.
o Direct connections to the TOE from an unprotected network (example FTP
connections) must not be allowed in the site security policy.
o The TOE’s interfaces must be configured to protect against IP Spoofing attempts
in which a packet arrives on an interface other than that identified by its source
address.
o It is not recommended to change the default setting of the “audit full condition”
for the TOE to any other settings, since the TOE by default is set to shut down the
network traffic if the audit space becomes full in order not to allow any traffic to
pass where the audit of such traffic is not taking place.
o The TOE must be configured to proxy all Telnet network traffic.
o The TOE must be configured to proxy all FTP network traffic.
7
In the evaluated configuration, the onbard NIC cards shall not be used for the means of providing external
network interface(s).
20
CyberGuard Firewall/VPN Version 6.2.1 Security Target
o The TOE must be configured to proxy all HTTP network traffic.
o The TOE must be configured to proxy all SMTP network traffic.
o Users of network services Telnet and FTP must be set up with a single-use token-
based method of authentication, not reusable password mechanism.
o User blacklisting feature must be enabled (it is not enabled by default).
o The “Set Blacklist Duration (minutes)” checkbox must also be enabled (not
enabled by default). This field, when checked specifies the duration of time a user
remains blacklisted. It is recommended that a large value to be set for this field
(maximum number 2,147,483,647), in order to keep a user blacklisted until the
administrator reviews and releases such users (as per requirements of the [PP]).
o The “Number of Failed Logon Attempts” field for repeated unsuccessful login
attempt is set to three by default. Although the site security policy may dictate a
different value for this field, it is not recommended to set this allowable number
of attempts to a very large value.
o A value of 60 seconds has been configured by default for “Time Duration
(seconds)” field of the user-blacklisting page. This is the duration of time in
which the users are allowed to attempt to authenticate. Although the site security
policy may dictate a different value for this field, but it is not recommend setting
this value to a very high values.
o Both the authentication server and the management station must be configured
using either as a direct connection to the TOE or from an internal protected
network, or afforded the same physical protection and access control as required
for the TOE.
2.5.1 Network Security Policy
In the evaluated configuration, the standard supplied hardware and software that
constitute the TOE must be configured in accordance with a defined network security
policy. Services other than those explicitly allowed by the network security policy must
not be enabled, so that traffic permitted to flow through the firewall is restricted to that
which is authorized.
In defining a network security policy, it is necessary that the firewall be configured so
that no direct connections to the firewall are allowed and remote administration
capabilities are not configured. This implies that no connections such as the Telnet or the
FTP application sessions shall be allowed into the firewall. The firewall as a bastion host
shall however provide proxy services such as Telnet, FTP, HTTP and SMTP.
The recommendations outlined in the CyberGuard Firewall/VPN Version 6.2.1 Firewall
Manual [CGFM] must be followed in addition to the advice given here. These
recommendations cover administrative actions ensuring that administration users have
passwords assigned, that the passwords are not disclosed, that the system is implemented
and tested in incremental stages, and that the audit trail is configured to shut down on
audit failures in order to create an air gap and to record invalid IP packets rather than all
IP packets.
21
CyberGuard Firewall/VPN Version 6.2.1 Security Target
2.5.2 IP Packet Interface Checking
The evaluated configuration has IP-Forwarding capabilities disabled and interface
checking capabilities enabled, to detect packets that arrive on interfaces inconsistent with
their addressing. This mechanism enables the TOE to counter common forms of IP
spoofing attempts in which when a packet arrives on an interface other than that
identified by its source address it will be rejected (dropped).
2.5.3 Auditing
The evaluated configuration for auditing is to shutdown traffic when audit trail becomes
full. The [CGFM] provides guidance on how to configure other reactions to a full audit
trail.
2.5.4 NAT
The evaluated configuration has NAT enabled to hide internal network addresses from
external hosts, while allowing network services to be routed through the firewall. Local
IP addresses are translated to one of the firewall’s registered external IP interface
addresses so that, from outside, all traffic appears to be originating from or terminating at
the firewall.
2.5.5 Proxies
The evaluated configuration has the following proxies enabled. The method of
authentication, wherever applicable, for users of these proxies must be set as single-use
authentication mechanism, using the RSA Authentication Manager 6.0:
A) Telnet proxy
B) FTP proxy
C) HTTP
D) SMTP
The [CGFM] provides guidance on how to configure these proxies.
2.5.6 Administrative Interfaces
The evaluated configuration covers local administration of the TOE using the
Management Software (Graphical User Interface). The Management Software station
must be configured using either a direct connection to the firewall, or across a protected
subnet such as a DMZ, and be located along with the firewall in a physically secure
location that allows authorized access to the TOE only. In addition, it is recommended
that one administrator role with all administrative capabilities be created and used to
manage the firewall. [CGFM] provides guidance on how to configure the firewall to
accept only local administration.
22
CyberGuard Firewall/VPN Version 6.2.1 Security Target
2.6 Security Policy Model (SPM)
The Security Policy Model requirement (ADV_SPM.1) is met by this Security Target.
23
CyberGuard Firewall/VPN Version 6.2.1 Security Target
CHAPTER 3
3. Security Environment
This chapter identifies the following:
A) Significant assumptions about the TOE’s operational environment.
B) IT related threats to the organisation countered by the TOE.
C) Environmental threats requiring controls to provide sufficient protection.
D) Organizational security policies for the TOE as appropriate.
Using the above listing, this chapter identifies assumptions (A), threats (T) and
organisational security policies (P). For assumptions, threats or policies that apply to the
environment, the initial character is followed by a period and then an ‘E’. For example,
T.E.PHYSICAL is a security environmental threat of unauthorised physical access.
3.1 Assumptions
The specific conditions listed in the following subsections are assumed to exist in the
TOE environment. These assumptions include both practical realities in the development
of the TOE security requirements and the essential environmental conditions on the use
of the TOE.
3.1.1 Connectivity Assumptions
A.SINGEN Information cannot flow among the internal and external networks
unless it passes through the TOE.
A.DIRECT Human users within the physically secure boundary protecting the
TOE may attempt to access the TOE from some direct connection
(e.g., a console port) if the connection is part of the TOE.
A.NOREMO Human users who are not authorized administrators cannot access
the TOE remotely from the internal or external networks.
A.REMACC8
Authorized administrators may only access the TOE locally.
3.1.2 Personnel Assumptions
A.MODEXP The threat of malicious attacks aimed at discovering exploitable
vulnerabilities is considered moderate.
8
The TOE does not claim conformance to the optional remote administration. Hence authorized
administrator are allowed to access the TOE only locally.
24
CyberGuard Firewall/VPN Version 6.2.1 Security Target
A.NOEVIL Authorized administrators are non-hostile and follow all
administrator guidance; however, they are capable of error.
A.TRAIN Firewall Administrators are assumed to be suitably qualified.
3.1.3 Physical Assumptions
A.PHYSEC The TOE is physically secure.
A.GENPUR There are no general-purpose computing capabilities (e.g., the
ability to execute arbitrary code or applications) and storage
repository capabilities on the TOE.
A.PUBLIC The TOE does not host public data.
3.2 Threats
The following threats are addressed either by the TOE or the environment..
3.2.1 Threats Addressed by the TOE
T.NOAUTH An unauthorized person may attempt to bypass the security of the
TOE so as to access and use security functions and/or non-security
functions provided by the TOE.
T.REPEAT An unauthorized person may repeatedly try to guess authentication
data in order to use this information to launch attacks on the TOE.
T.REPLAY An unauthorized person may use valid identification and
authentication data obtained to access functions provided by the
TOE.
T.ASPOOF An unauthorized person may carry out spoofing in which
information flow through the TOE into a connected network by
using a spoofed source address. An unauthorized person on an
external network may attempt to by-pass the information flow
control policy by disguising authentication data (e.g., spoofing the
source address) and masquerading as a legitimate user or entity on
an internal network.
T.MEDIAT An unauthorized person may send impermissible information
through the TOE, which results in the exploitation of resources on
the internal network.
T.OLDINF Because of a flaw in the TOE functioning, an unauthorized person
may gather residual information from a previous information flow
or internal TOE data by monitoring the padding of the information
flows from the TOE.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
T.PROCOM9
An unauthorized person or unauthorized external IT entity may be
able to view, modify, and/or delete security related information
that is sent between a remotely located authorized administrator
and the TOE.
T.AUDACC Persons may not be accountable for the actions that they conduct
because the audit records are not reviewed, thus allowing an
attacker to escape detection.
T.SELPRO An unauthorized person may read, modify, or destroy security
critical TOE configuration data.
T.AUDFUL An unauthorized person may cause audit records to be lost or
prevent future records from being recorded by taking actions to
exhaust audit storage capacity, thus masking an attackers actions.
T.MODEXP A skilled attacker with moderate attack potential may attempt to
bypass the TSF to gain access to the TOE or the assets it protects.
3.2.2 Threats to be Addressed by Operational Environment
T.E.TUSAGE The TOE may be inadvertently configured, used and administered
in an insecure manner by either authorized or unauthorized
persons.
3.3 Organizational Security Policies
P.CRYPTO Triple DES encryption, as specified in FIPS 46-3 (3) must be used
to protect remote administration functions, as the associated
cryptographic module must comply, at a minimum, with FIPS 140-
1 (level1)10
Environments.
9
This threat is not applicable to this ST, since both the protection profiles (i.e., TF-MRPP & AP-MRPP)
that require this threat to be addressed by the ST writer make Remote Administration an optional
component. Since the TOE does not claim remote administration, this threat is therefore outside the scope
of the TOE.
10
This organizational security policy is not applicable to this ST, since both the protection profiles (i.e.,
TF-MRPP & AP-MRPP) that require this policy also make Remote Administration an optional component.
Since the TOE does not claim remote administration, this policy is therefore outside the scope of the TOE
and as such, it is not implemented.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
CHAPTER 4
4. Security Objectives
4.1 Security Objectives for the TOE
All of the objectives listed in this section ensure that all of the security threats listed in
Chapter 3 have been countered, and all of the policies have been implemented. The
security objectives (O) for CyberGuard Firewall/VPN Version 6.2.1 are:
O.IDAUTH The TOE must uniquely identify and authenticate the claimed
identity of all users, before granting a user access to TOE functions
or, for certain specified services, to a connected network.
O.SINUSE The TOE must prevent the reuse of authentication data for users
attempting to authenticate to the TOE from a connected network.
O.MEDIAT The TOE must mediate the flow of all information between clients
and servers located on internal and external networks governed by
the TOE, disallowing passage of non-conformant protocols and
ensuring that residual information from a previous information
flow is not transmitted in any way.
O.SECSTA Upon initial start-up of the TOE or recovery from an interruption
in TOE service, the TOE must not compromise its resources or
those of any connected network.
O.SELPRO The TOE must protect itself against attempts by unauthorized users
to bypass, deactivate, or tamper with TOE security functions.
O.AUDREC The TOE must provide a means to record a readable audit trail of
security-related events, with accurate dates and times, and a means
to search and sort the audit trail based on relevant attributes.
O.ACCOUN The TOE must provide user accountability for information flows
through the TOE and for authorized administrator use of security
functions related to audit.
O.SECFUN The TOE must provide functionality that enables an authorized
administrator to use the TOE security functions, and must ensure
that only authorized administrators are able to access such
functionality.
O.LIMEXT The TOE must provide the means for an authorized administrator
to control and limit access to TOE security functions by an
authorized external IT entity.
O.EAL The TOE must be structurally tested and shown to be resistant to
obvious vulnerabilities.
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4.2 Security Objectives for the IT Environment
O.E.PHYSEC The TOE is physically secure.
O.E.MODEXP The threat of malicious attacks aimed at discovering exploitable
vulnerabilities is considered moderate.
O.E.GENPUR There are no general-purpose computing capabilities (e.g., the
ability to execute arbitrary code or applications) and storage
repository capabilities on the TOE.
O.E.PUBLIC The TOE does not host public data.
O.E.NOEVIL Authorized administrators are non-hostile and follow all
administrator guidance; however, they are capable of error.
O.E.SINGEN Information cannot flow among the internal and external networks
unless it passes through the TOE.
O.E.DIRECT Human users within the physically secure boundary protecting the
TOE may attempt to access the TOE from some direct connection
(e.g., a console port) if the connection is part of the TOE.
O.E.NOREMO Human users who are not authorized administrators cannot access
the TOE remotely from the internal or external networks.
O.E.REMACC11
Authorized administrators may only access the TOE locally.
O.E.GUIDAN The TOE must be delivered, installed, administered, and operated
in a manner that maintains security.
O.E.ADMTRA Authorized administrators are trained as to establishment and
maintenance of security policies and practices.
11
The TOE does not claim conformance to the optional remote administration. Hence authorized
administrator are allowed to access the TOE only locally.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
CHAPTER 5
5. IT Security Requirements
This section contains the functional requirements that are provided by the TOE. These
requirements consist of functional components from Part 2 of the CC.
5.1 TOE Security Functional Requirements
The functional requirements are described in detail in the following subsections.
Additionally, these requirements are derived from Part 2 of the Common Criteria for
Information Technology Security Evaluation, Version 2.2.
The following table (Table 4 - below) has been utilized to indicate all the functional
components the TOE claims conformance with. It also indicates the Protection Profiles
that mandates each one of the mentioned functional components including those that are
common to both the PPs.
Table 4 - Functional Components of the TOE
AP-MRPP TF-MRPP CC FUNCTIONAL COMPONENT
DESCRIPTION
FMT_SMR.1 FMT_SMR.1 Security roles
FIA_ATD.1 FIA_ATD.1 User attribute definition
FIA_UID.2 FIA_UID.2 User identification before any
action
FIA_AFL.1 FIA_AFL.1 Authentication failure handling
FIA_UAU.5 FIA_UAU.5 Multiple authentication
mechanisms
FDP_IFC.1 (1) FDP_IFC.1 Subset information flow control
(1)
FDP_IFC.1 (2) Subset information flow control
(2)
FDP_IFF.1 (1) FDP_IFF.1 Simple security attributes (1)
FDP_IFF.1 (2) Simple security attributes (2)
FMT_MSA.1 (1) FMT_MSA.1 (1) Management of security attributes
(1)
FMT_MSA.1 (2) FMT_MSA.1 (2) Management of security attributes
(2)
CC
F
UNCTIONAL
C
OMPONENTS
FMT_MSA.1 (3) Management of security attributes
(3)
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
AP-MRPP TF-MRPP CC FUNCTIONAL COMPONENT
DESCRIPTION
FMT_MSA.1 (4) Management of security attributes
(4)
FMT_MSA.3 FMT_MSA.3 Static attribute initialization
FMT_MTD.1 (1) FMT_MTD.1 (1) Management of TSF data (1)
FMT_MTD.1 (2) FMT_MTD.1 (2) Management of TSF data (2)
FMT_MTD.2 FMT_MTD.2 Management of limits on TSF data
FDP_RIP.1 FDP_RIP.1 Subset residual information
protection
FCS_COP.1 FCS_COP.1 Cryptographic operation
FPT_RVM.1 FPT_RVM.1 Non-bypassability of the TSP
FPT_SEP.1 FPT_SEP.1 TSF domain separation
FPT_STM.1 FPT_STM.1 Reliable time stamps
FAU_GEN.1 FAU_GEN.1 Audit data generation
FAU_SAR.1 FAU_SAR.1 Audit review
FAU_SAR.3 FAU_SAR.3 Selectable audit review
FAU_STG.1 FAU_STG.1 Protected audit trail storage
FAU_STG.4 FAU_STG.4 Prevention of audit data loss
FMT_MOF.1 (1) FMT_MOF.1 (1) Management of security functions
behavior (1)
FMT_MOF.1 (2) FMT_MOF.1 (2) Management of security functions
behavior (2)
In general, the Strength of Function for this TOE is SOF-Medium. Specific strength of
function metrics are provided for FIA_UAU.5 - Strength of Function is in compliance
with the “Statistical random number generator tests” found in section 4.11.1 of FIPS PUB
140-1 and the “Continuous random number generator test” found in section 4.11.2 of
FIPS PUB 140-1 [4]. Strength of function for the password authentication mechanism is
that the probability that authentication data can be guessed is no greater than one in two
to the fortieth (2^40). The single-use and password authentication mechanisms must
demonstrate SOF-medium, as defined in Part 1 of the CC.
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5.1.1 Security Audit (FAU)
5.1.1.1 FAU_GEN.1 Audit Data Generation
Hierarchical to: No other components.
FAU_GEN.1.1 - The TSF shall be able to generate an audit record of the following
auditable events:
a) Start-up and shutdown of the audit functions;
b) All auditable events for the not specified level of audit; and
c) [the events in Table 5].
FAU_GEN.1.2 - The TSF shall record within each audit record at least the following
information:
a) Date and time of the event, type of event, subject identity, outcome (success
or failure) of the event; and
b) For each audit event type, based on the auditable event definitions of the
functional components included in the PP/ST, [information specified in
column three of Table 5].
Dependencies: FPT_STM.1 Reliable Time Stamps.
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Table 5 - Auditable Events (Table 5.2 in TF-MRPP & AP-MRPP)
Functional
Component
Auditable Event
Additional Audit Record
Contents
FMT_SMR.1 Modifications to the group of
users that are part of the
authorized administrator
role.
Unsuccessful attempts to
authenticate the authorized
administrator role.
The identity of the authorized
administrator performing the
modification and the user
identity being associated with
the authorized administrator
role.
The user identity and the role.
FIA_UID.2 All use of the user
identification mechanism.
The user identities provided to
the TOE.
FIA_UAU.5 The final decision on
authentication.
The user identity and the
success or failure of the
authentication.
FIA_AFL.1 The reaching of the threshold
for unsuccessful authentication
attempts and the subsequent
restoration by the authorized
administrator of the users
capability to authenticate.
The identity of the offending
user and the authorized
administrator.
FDP_IFF.1 All decisions on requests for
information flow.
The presumed addresses of the
source and destination subject.
FPT_STM.1 Changes to the time. The identity of the authorized
administrator performing the
operation.
FMT_MOF.1 Use of the functions listed in
this requirement pertaining to
audit.
The identity of the authorized
administrator performing the
operation.
Note: The requirement to audit contents of functional component FCS_COP.1 is not
applicable to this ST as both the protection profiles (i.e., TF-MRPP & AP-MRPP) used to
instantiate this ST make Remote Administration an optional component. Since the TOE
does not claim remote administration, and hence compliance to the FCS_COP.1, this
requirement is therefore outside the scope of the TOE and as such is not implemented or
included here.
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5.1.1.2 FAU_SAR.1 Audit Review
Hierarchical to: No other components.
FAU_SAR.1.1 - The TSF shall provide [an authorized administrator] with the capability
to read [all audit trail data] from the audit records.
FAU_SAR.1.2 - The TSF shall provide the audit records in a manner suitable for the user
to interpret the information.
Dependencies: FAU_GEN.1 Audit Data Generation.
5.1.1.3 FAU_SAR.3 Selectable Audit Review
Hierarchical to: No other components.
FAU_SAR.3.1 - The TSF shall provide the ability to perform searches and sorting of
audit data based on:
a) [user identity;
b) presumed subject address;
c) ranges of dates;
d) ranges of times;
e) ranges of addresses].
Application Note: Searching and Sorting is provided by a query tool builtin the TOE.
Dependencies: FAU_SAR.1 Audit Review.
5.1.1.4 FAU_STG.1 Protected Audit Trail Storage
Hierarchical to: No other components.
FAU_STG.1.1 - The TSF shall protect the stored audit records from unauthorized
deletion.
FAU_STG.1.2 - The TSF shall be able to prevent unauthorized modifications to the
audit records in the audit trail.
Dependencies: FAU_GEN.1 Audit Data Generation.
5.1.1.5 FAU_STG.4 Prevention of Audit Data Loss
Hierarchical to: FAU_STG.3 Action in Case of Possible Audit Data Loss.
FAU_STG.4.1 - The TSF shall prevent auditable events, except those taken by the
authorized administrator and [shall limit the number of audit records lost] if the audit
trail is full.
Application Note: The ‘Security Requirements Rationale’ section provides an analysis of
the maximum amount of audit data that might be lost in the event of audit storage failure,
exhaustion and/or attack.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Dependencies: FAU_STG.1 Protected Audit Trail Storage.
5.1.2 User Data Protection (FDP)
Requirements Overview: This Security Target consists of multiple information flow
control Security Function Policies (SFPs). The CC allows multiple policies to exist, each
having a unique name. This is accomplished by iterating FDP_IFC.1 for each of the two
named information flow control policies. The first policy identified is called the
UNAUTHENTICATED SFP. The subjects under control of this policy are external IT
entities on an internal or external network sending information through the TOE to other
external IT entities. The second policy identified is called the AUTHENTICATED SFP.
The subjects under control of this policy are human users on an internal or external
network who must be authenticated at the TOE before using the services in FIA_UAU.5.
The information flowing between subjects in both policies is traffic with attributes,
defined in FDP_IFF.1.1, including source and destination addresses. The rules that define
each information flow-control SFP are found in FDP_IFF.1.2. Component FDP_IFF.1 is
iterated twice to correspond to each of the two iterations of FDP_IFC.1.
5.1.2.1 FDP_IFC.1 Subset Information Flow Control (1)
Hierarchical to: No other components.
FDP_IFC.1.1 - The TSF shall enforce the [UNAUTHENTICATED SFP] on:
a) [subjects: unauthenticated external IT entities that send and receive information
through the TOE to one another;
b) information: traffic sent through the TOE from one subject to another; and
c) operation: pass information with Network Address Translation].
Dependencies: FDP_IFF.1 Simple Security Attributes (1).
5.1.2.2 FDP_IFC.1 Subset Information Flow Control (2)
Hierarchical to: No other components.
FDP_IFC.1.1 - The TSF shall enforce the [AUTHENTICATED SFP] on:
a. [subjects: a human user or external IT entity that sends and receives FTP and
Telnet information through the TOE to one another, only after the human user
initiating the information flow has authenticated at the TOE per FIA_UAU.5,
b. information: FTP and Telnet traffic sent through the TOE from one subject to
another;
c. operation: initiate service and pass information with Network Address
Translation].
Dependencies: FDP_IFF.1 Simple Security Attributes (2).
5.1.2.3 FDP_IFF.1 Simple Security Attributes (1)
Hierarchical to: No other components.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
FDP_IFF.1.1 - The TSF shall enforce the [UNAUTHENTICATED SFP] based on at
least the following types of subject and information security attributes:
a) [subject security attributes:
• presumed address;
• and no additional subject security attributes
b) information security attributes:
• presumed address of source subject;
• presumed address of destination subject;
• transport layer protocol;
• TOE interface on which traffic arrives and departs;
• service;
• and no additional information security attributes].
FDP_IFF.1.2 - The TSF shall permit an information flow between a controlled subject
and another controlled subject via a controlled operation if the following rules hold:
a) [Subjects on an internal network can cause information to flow through the
TOE to another connected network if:
• all the information security attribute values are unambiguously
permitted by the information flow security policy rules, where such
rules may be composed from all possible combinations of the values of
the information flow security attributes, created by the authorized
administrator;
• the presumed address of the source subject, in the information,
translates to an internal network address;
• and the presumed address of the destination subject, in the
information, translates to an address on the other connected network.
b) Subjects on the external network can cause information to flow through the
TOE to another connected network if:
• all the information security attribute values are unambiguously
permitted by the information flow security policy rules, where such
rules may be composed from all possible combinations of the values of
the information flow security attributes, created by the authorized
administrator;
• the presumed address of the source subject, in the information,
translates to an external network address; and
• the presumed address of the destination subject, in the information,
translates to an address on the other connected network.]
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
FDP_IFF.1.3 - The TSF shall enforce the following information flow control rules: [no
additional information control SFP rules].12
FDP_IFF.1.4 - The TSF shall provide the following [no additional SFP capabilities].12
FDP_IFF.1.5 - The TSF shall explicitly authorize an information flow based upon the
following rules: [no explicit authorization rules].12
FDP_IFF.1.6 - The TSF shall explicitly deny an information flow based upon the
following rules:
a) [The TOE shall reject requests for access or services where the information
arrives on an external TOE interface, and the presumed address of the source
subject is an external IT entity on an internal network;
b) The TOE shall reject requests for access or services where the information arrives
on an internal TOE interface, and the presumed address of the source subject is an
external IT entity on the external network;
c) The TOE shall reject requests for access or services where the information arrives
on either an internal or external TOE interface, and the presumed address of the
source subject is an external IT entity on a broadcast network;
d) The TOE shall reject requests for access or services where the information arrives
on either an internal or external TOE interface, and the presumed address of the
source subject is an external IT entity on the loopback network;
e) The TOE shall reject requests in which the subject specifies the route in which
information shall flow en route to the receiving subject; and
f) For application protocols HTTP and SMTP supported by the TOE, the TOE shall
deny any access or service requests that do not conform to its associated
published protocol specification (e.g., RFC). This shall be accomplished through
protocol filtering proxies that are designed for that purpose.]
Application Note: The generalized wording of FDP_IFF.1.6f (1) has been modified
from the PP to highlight that only HTTP and SMTP proxies are included in the TOE.
The DNS & POP3 application level proxies are not included in the TOE and hence
are not applicabple.
Dependencies: FDP_IFC.1 Subset Information Flow Control (1),
FMT_MSA.3 Static Attribute Initialization.
5.1.2.4 FDP_IFF.1 Simple Security Attributes (2)
Hierarchical to: No other components.
FDP_IFF.1.1 - The TSF shall enforce the [AUTHENTICATED SFP] based on at least
the following types of subject and information security attributes
a) [subject security attributes:
12
This change has been made to conform to U.S. Interpretation I-0407.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
• presumed address;
• no additional subject security attributes;
b) information security attributes:
• user identity;
• presumed address of source subject;
• presumed address of destination subject;
• transport layer protocol;
• TOE interface on which traffic arrives and departs;
• service (i.e., FTP and Telnet);
• security-relevant service command; and
• no additional information security attributes].
FDP_IFF.1.2 - The TSF shall permit an information flow between a controlled subject
and another controlled subject via a controlled operation if the following rules hold:
a) [Subjects on an internal network can cause information to flow through the
TOE to another connected network if:
• the human user initiating the information flow authenticates according
FIA_UAU.5;13
• all the information security attribute values are unambiguously
permitted by the information flow security policy rules, where such
rules may be composed from all possible combinations of the values of
the information flow security attributes, created by the authorized
administrator;
• the presumed address of the source subject, in the information,
translates to an internal network address; and
• the presumed address of the destination subject, in the information,
translates to an address on the other connected network.
b) Subjects on the external network can cause information to flow through the
TOE to another connected network if:
13
There is a typographical error in the AP-MRPP with respect to FDP_IFF.1(1) and FDP_IFF.1(2). The PP
authors have included the phrase, "the human user initiating the information flow authenticates according
to FIA_UAU.5," in FDP_IFF.1.2(1) UNAUTHENTICATED SFPs and it is absent in FDP_IFF.1.2(2)
AUTHENTICATED SFPs, where it really belongs. This has been rectified in this ST. For details please
refer to the ‘Precedent Database’ at http://niap.nist.gov/cc-scheme/PD/0026.html.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
• the human user initiating the information flow authenticates according
FIA_UAU.513
• all the information security attribute values are unambiguously
permitted by the information flow security policy rules, where such
rules may be composed from all possible combinations of the values of
the information flow security attributes, created by the authorized
administrator;
• the presumed address of the source subject, in the information,
translates to an external network address;
• and the presumed address of the destination subject, in the
information, translates to an address on the other connected network.]
FDP_IFF.1.3 - The TSF shall enforce the following information flow control rules: [no
additional information control SFP rules].14
FDP_IFF.1.4 - The TSF shall provide the following [no additional SFP capabilities].14
FDP_IFF.1.5 - The TSF shall explicitly authorize an information flow based upon the
following rules: [no explicit authorization rules].14
FDP_IFF.1.6 - The TSF shall explicitly deny an information flow based upon the
following rules:
a) [The TOE shall reject requests for access or services where the information
arrives on an external TOE interface, and the presumed address of the source
subject is an external IT entity on an internal network;
b) The TOE shall reject requests for access or services where the information arrives
on an internal TOE interface, and the presumed address of the source subject is an
external IT entity on the external network;
c) The TOE shall reject requests for access or services where the information arrives
on either an internal or external TOE interface, and the presumed address of the
source subject is an external IT entity on a broadcast network;
d) The TOE shall reject requests for access or services where the information arrives
on either an internal or external TOE interface, and the presumed address of the
source subject is an external IT entity on the loopback network;
e) The TOE shall reject requests in which the subject specifies the route in which
information shall flow en route to the receiving subject; and
f) The TOE shall reject Telnet or FTP command requests that do not conform to
generally accepted published protocol definitions (e.g., RFCs). This must be
accomplished through protocol filtering proxies designed for that purpose.]
14
This change has been made to conform to U.S. Interpretation I-0407.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Application Note: The TOE can make no claim as to the real address of any source or
destination subject, therefore the TOE can only suppose that these addresses are accurate.
Therefore, a “presumed address” is used to identify source and destination addresses. A
“service”, listed in FDP_IFF.1.1(b), could be identified, for example, by a source port
number and/or destination port number. A “service command”, also mentioned
FDP_IFF.1.1(b), could be identified, for example, in the case of the File Transport
protocol (FTP) service as an FTP STOR or FTP RETR.
Dependencies: FDP_IFC.1 Subset Information Flow Control (2),
FMT_MSA.3 Static Attribute Initialization
5.1.2.5 FDP_RIP.1 Subset Residual Information Protection
Hierarchical to: No other components.
FDP_RIP.1.1 - The TSF shall ensure that any previous information content of a resource
is made unavailable upon the allocation of the resource to [all objects].
Application Note: This requirement is met by zeroing all de-allocated and newly
allocated memory pages.
Dependencies: No dependencies.
5.1.3 Identification and Authentication (FIA)
5.1.3.1 FIA_AFL.1 Authentication Failure Handling15
Hierarchical to: No other components.
FIA_AFL.1.1 - The TSF shall detect when [an administrator configurable positive
integer within a range of 1-3 ] of unsuccessful authentication attempts occur related to
[authorized TOE administrator access or authorized TOE IT entity access].
FIA_AFL.1.2 - When the defined number of unsuccessful authentication attempts has
been met or surpassed, the TSF shall [prevent the offending user from successfully
authenticating until an authorized administrator takes some action to make authentication
possible for the user in question.]
Dependencies: FIA_UAU.1 Timing of Authentication.
5.1.3.2 FIA_ATD.1 User Attribute Definition
Hierarchical to: No other components.
15
The TOE does not claim the optional remote administration functionality and hence the SFR,
FIA_AFL.1, as mentioned in the TF-MRPP and AP-MRPP is not applicable to the TOE. It has however
been included in this ST to handle authentication failure handling of the remote proxy (telnet, ftp) users and
local administrator as required by the AP-MRPP and TF-MRPP.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
FIA_ATD.1.1 - The TSF shall maintain the following list of security attributes belonging
to individual users:
a) [identity;
b) association of a human user with the authorized administrator role;
c) and no additional security attributes].
Dependencies: No dependencies.
5.1.3.3 FIA_UAU.5 Multiple Authentication Mechanisms
Hierarchical to: No other components.
FIA_UAU.5.1 - The TSF shall provide [password and single-use authentication
mechanisms] to support user authentication.
FIA_UAU.5.2 - The TSF shall authenticate any user’s claimed identity according to the
[following multiple authentication mechanism rules:
a) single-use authentication mechanism shall be used for authorized
administrators to ace ss the TOE remotely such that successful
authentication must be achieved before allowing any other TSF-mediated
actions on behalf of that authorized administrator.16
b) Single-use authentication mechanism shall be used for authorized external IT
entities accessing the TOE such that successful authentication must be
achieved before allowing any other TSF-mediated actions on behalf of that
authorized external IT entity16
;
c) single-use authentication mechanism shall be used for human users sending or
receiving information through the TOE using FTP or Telnet such that
successful authentication must be achieved before allowing any other TSF-
mediated actions on behalf of that human user;
d) reusable password mechanism shall be used for authorized administrators to
access the TOE via a directly connected terminal such that successful
authentication must be achieved before allowing any other TSF-mediated
actions on behalf of that authorized administrator].
Application Note: Rules a and b are not applicable because the TOE does not claim
conformance to the optional remote administrator access or for authorized external IT
entities.
Dependencies: No dependencies.
16
The TOE does not claim conformance to the optional remote administration. As a result, single use
authentication required by administrators for remote access or by authorized external IT entities is not
applicable to this TOE. This functional requirement has only been duplicated here for completeness.
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5.1.3.4 FIA_UID.2 User Identification Before any Action
Hierarchical to: No other components.
FIA_UID.2.1 - The TSF shall require each user to identify itself before allowing any
other TSF-mediated actions on behalf of that user.
Dependencies: No dependencies.
5.1.4 Security Management (FMT)
5.1.4.1 FMT_MOF.1 Management of Security Functions Behavior (1)
Hierarchical to: No other components.
FMT_MOF.1.1(1) - The TSF shall restrict the ability to enable, disable the functions
a) [operation of the TOE;
b) multiple use authentication functions described in FIA_UAU.5]
to [an authorized administrator].
Application Note: By “Operation of the TOE” in a) above, we mean having the TOE start
up (enable operation) and shut down (disable operation). By “multiple use” in b) above,
we mean the management of password and single-use authentication mechanisms.
Dependencies: FMT_SMR.1 Security Roles.
FMT_SMF.1 Specification of Management Function17
5.1.4.2 FMT_MOF.1 Management of Security Functions Behavior (2)
Hierarchical to: No other components.
FMT_MOF.1.1(2) - The TSF shall restrict the ability to enable, disable, determine and
modify the behavior of the functions
a) [ audit trail management;
b) backup and restore for TSF data, information flow rules, and audit trail data;
and
c) communication of authorized external IT entities with the TOE ] to [an
authorized administrator].
17
The SFRs FMT_MOF.1 (1-2), FMT_MSA.1 (1-4) and FMT_MTD.1 (1-2) have a dependency on the
SFR FMT_SMF.1 (which is a new addition to the CC Part 2 version 2.2). Albeit the two protection profiles
used to instantiate this ST did not include the mentioned dependency, as they were evaluated against CC
Part 2 version 2.1, this ST has included the mentioned dependency for each one of the specified SFRs.
Please refer to [CC2] document to view the SFR FMT_SMF.1.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Application Note: Determine and modify the behavior of element c (communication of
authorized external IT entities with the TOE) is intended to cover functionality such as
providing a range of addresses from which the authorized external entity can connect.
Dependencies: FMT_SMR.1 Security Roles.
FMT_SMF.1 Specification of Management Function17
5.1.4.3 FMT_MSA.1 Management of Security Attributes (1)
Hierarchical to: No other components.
FMT_MSA.1.1 (1) - The TSF shall enforce the [UNAUTHENTICATED_SFP] to restrict
the ability to [delete attributes from a rule, modify attributes in a rule, and add attributes
to a rule] the security attributes [listed in section FDP_IFF1.1(1)] to [the authorized
administrator].
Dependencies: FDP_IFC.1 Subset Information Flow Control(1), FMT_SMR.1 Security
Roles, FMT_SMF.1 Specification of Management Function17
.
5.1.4.4 FMT_MSA.1 Management of Security Attributes (2)
Hierarchical to: No other components.
FMT_MSA.1.1 (2) - The TSF shall enforce the [AUTHENTICATED_SFP] to restrict the
ability to [delete attributes from a rule, modify attributes in a rule, add attributes to a rule]
the security attributes [listed in section FDP_IFF.1(2)] to [the authorized administrator].
Dependencies: FDP_IFC.1 Subset Information Flow Control(2), FMT_SMR.1 Security
Roles, FMT_SMF.1 Specification of Management Function17
.
5.1.4.5 FMT_MSA.1 Management of Security Attributes (3)
Hierarchical to: No other components.
FMT_MSA.1.1 (3) - The TSF shall enforce the [UNAUTHENTICATED_SFP] to restrict
the ability to delete and [create] the security attributes [information flow rules described
in FDP_IFF.1(1)] to [the authorized administrator].
Dependencies: FDP_IFC.1 Subset Information Flow Control(1), FMT_SMR.1 Security
Roles, FMT_SMF.1 Specification of Management Function17
.
5.1.4.6 FMT_MSA.1 Management of Security Attributes (4)
Hierarchical to: No other components.
FMT_MSA.1.1(4) - The TSF shall enforce the [AUTHENTICATED_SFP] to restrict the
ability to delete and [create] the security attributes [information flow rules described in
FDP_IFF.1(2)] to [the authorized administrator].
Dependencies: FDP_IFC.1 Subset Information Flow Control(2), FMT_SMR.1 Security
Roles, FMT_SMF.1 Specification of Management Function17
.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
5.1.4.7 FMT_MSA.3 Static Attribute Initialization
Hierarchical to: No other components.
FMT_MSA.3.1 - The TSF shall enforce the [UNAUTHENTICATED_SFP and
AUTHENTICATED_SFP] to provide restrictive default values for information flow
security attributes that are used to enforce the SFP.
FMT_MSA.3.2 - The TSF shall allow the [the authorized administrator] to specify
alternative initial values to override the default values when an object or information is
created.
Application Note: Following TOE installation, the default configuration is to allow no
traffic through the firewall. The default values for the information flow control security
attributes appearing in FDP_IFF.1 (1) and FDP_IFF.1 (2) are intended to be restrictive in
the sense that both inbound and outbound information is denied by the TOE until the
default values are modified by an authorized administrator.
Dependencies: FMT_MSA.1 Management of Security Attributes (1-4),
FMT_SMR.1 Security Roles.
5.1.4.8 FMT_MTD.1 Management of TSF Data (1)
Hierarchical to: No other components.
FMT_MTD.1.1 (1) - The TSF shall restrict the ability to query, modify, delete, [and
assign] the [user attributes defined in FIA_ATD.1.1] to [the authorized administrator].
Dependencies: FMT_SMR.1 Security Roles, FMT_SMF.1 Specification of Management
Function17
.
5.1.4.9 FMT_MTD.1 Management of TSF Data (2)
Hierarchical to: No other components.
FMT_MTD.1.1 (2) - The TSF shall restrict the ability to [set] the [time and date used to
form the timestamps in FPT_STM.1.1] to [the authorized administrator].
Dependencies: FMT_SMR.1 Security Roles, FMT_SMF.1 Specification of Management
Function17
.
5.1.4.10 FMT_MTD.2 Management of Limits on TSF Data
Hierarchical to: No other components.
FMT_MTD.2.1 - The TSF shall restrict the specification of the limits for [the number of
authentication failures] to [the authorized administrator].
FMT_MTD.2.2 - The TSF shall take the following actions, if the TSF data are at, or
exceed, the indicated limits: [actions specified in FIA_AFL.1.2].
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Dependencies: FMT_MTD.1 Management of TSF Data (1-2),
FMT_SMR.1 Security Roles.
5.1.4.11 FMT_SMR.1 Security Roles
Hierarchical to: No other components.
FMT_SMR.1.1 - The TSF shall maintain the role [authorized administrator].
FMT_SMR.1.2 - The TSF shall be able to associate human users with the authorized
administrator role.
Dependencies: No dependencies.
5.1.5 Protection of the TSF (FPT)
5.1.5.1 FPT_RVM.1 Non-Bypassability of the TSP
Hierarchical to: No other components.
FPT_RVM.1.1 - The TSF shall ensure that TSP enforcement functions are invoked and
succeed before each function within the TSC is allowed to proceed.
Dependencies: No dependencies.
5.1.5.2 FPT_SEP.1 TSF Domain Separation
Hierarchical to: No other components.
FPT_SEP.1.1 - The TSF shall maintain a security domain for its own execution that
protects it from interference and tampering by untrusted subjects.
FPT_SEP.1.2 - The TSF shall enforce separation between the security domains of
subjects in the TSC.
Dependencies: No dependencies.
5.1.5.3 FPT_STM.1 Reliable Time Stamps
Hierarchical to: No other components.
FPT_STM.1.1 The TSF shall be able to provide reliable time-stamps for its own use.
Application Note: The word “reliable” in the above requirement means that the order of
the occurrence of auditable events is preserved
Dependencies: No dependencies.
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5.2 TOE Security Assurance Requirements
The TOE meets the assurance requirements for EAL4 augmented18
which are
summarized in Table 6 - below.
Table 6 - Assurance Requirements of the TOE: EAL4 Augmented
Assurance Class Component ID Component Title
ACM_AUT.1 Partial CM automation
ACM_CAP.4 Generation support and
acceptance procedures
Configuration Management
ACM_SCP.2 Problem tracking CM
coverage
ADO_DEL.2 Detection of modification
Delivery and Operation
ADO_IGS.1 Installation, Generation,
and Start-Up Procedures
ADV_FSP.2 Fully Defined External
Interfaces
ADV_HLD.2 Security Enforcing High-
Level Design
ADV_IMP.1 Subset of the
Implementation of the TSF
ADV_LLD.1 Descriptive Low-Level
design
ADV_RCR.1 Informal Correspondence
Demonstration
Development
ADV_SPM.1 Informal TOE security
policy model
AGD_ADM.1 Administrator Guidance
Guidance Documents
AGD_USR.1 User Guidance
ALC_DVS.1 Identification of security
measures
Life Cycle Support
ALC_LCD.1 Developer defined life-
cycle model
18
The ‘Assurance Requirements’ mentioned in Error! Reference source not found. (EAL4 Augmented)
are as per the ‘Assurance Requirements’ mentioned in ‘Common Criteria for Information Technology
Security Evaluation Part 3 ( CC3)’.
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Assurance Class Component ID Component Title
ALC_TAT.1 Well-defined development
tools
ALC_FLR.3 Systematic Flaw
Remediation.
ATE_COV.2 Analysis of Coverage
ATE_DPT.1 Testing: high-level design
ATE_FUN.1 Functional Testing
Tests
ATE_IND.2 Independent Testing -
Sample
AVA_MSU.2 Validation of analysis
AVA_SOF.1 Strength of TOE Security
Function Evaluation
Vulnerability Assessment
AVA_VLA.2 Independent Vulnerability
Analysis
5.2.1 Additional Security Assurance Requirements
EAL4 was chosen for a moderate to high level of independently assured security in line
with strong commercial development practices. This section describes the maintenance
assurance requirements from the CC Part 3 that the TOE must satisfy in addition to the
previously listed EAL 4 SARs.
The ALC_FLR.3, Systematic Flaw Remediation was added to augment the EAL4 level of
evaluation . This augmentation, which is in line with the robust ‘Software Development
Life Cycle (SDLC)’ model already being followed by the TOE developer, was included
due to the strong consumer demand that the developer be able to systematically receive
security flaw reports, fix security flaws and dispatch corrective fixes to the TOE users in
a systematic, secure and a timely manner. ALC_FLR.3 is not included in any EAL. This
additional SAR is restated verbatim from the CC.
5.3 Security Requirements for the IT Environment
There are no explicit security requirements on the IT Security Environment.
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CHAPTER 6
6. TOE Summary Specification
6.1 TOE Security Functions
The security functions implemented by the TOE are:
TIME The TIME function maintains a reliable timestamp based on an initial time
obtained from the hardware platform. The TIME function then maintains a
software clock within the control of the TOE for stamping audit records
and synchronizes the software and hardware clocks so that consistent time
is maintained during operation of the TOE and at each boot up. The TIME
function provides the timestamp to the functions that generate audit
records, and to the audit reviewing functions thereby contributing in the
audit trail generation mechanism.
INTERCEPT The INTERCEPT function intercepts packets with the help of the external
NIC card. The NIC card performs basic address recognition checks on all
packets and filters out any that have a destination address different from
that of the NIC card itself. It subsequently transfers all accepted packets
to the other TOE security functions for filtering. CyberGuard Firewall
CGLinux kernel includes enhancements to the IP packet handling software
that ensure that all packets are forwarded to, and processed through the
filtering functions and that the filtering functions are not bypassable.
REAPER The REAPER function clears a released memory resource before it can be
re-used. CyberGuard Firewall CGLinux kernel contains enhancements to
the routines that free memory upon release/de-allocation. These
enhancements ensure that the routines that free memory upon release/de-
allocation also clear the contents of the freed memory before its reuse.
This memory content clearing mechanism results in residual information
protection.
NAT When configured for address translation, the TOE re-writes the headers of
IP packets flowing from the internal network to the external network, so that
the real addresses of internal hosts are hidden.
IAC The IAC function provides internal access control. It is an extension to the
CGLinux kernel and controls the kernel’s access routines and enforces
roles and credentials to provide separation of processes and data on the
CyberGuard Firewall to ensure that errors in non-trusted portions of the
firewall cannot propagate to the TOE security functions and non-
authorized entities can not modify its trusted security enforcing functions.
AUD_PROC The AUD_PROC function allows an authorized administrator to review
and clear audit records. The AUD_PROC function provides a mechanism
to allow itself and other Sub-Systems to submit significant event
information for storage and reporting. It collects the audit records
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submitted by the various functions of the TOE. The AUD_PROC function
provides an interface with the MGM function that allows these records to
be searched, sorted, displayed, and evaluated in compliance with the
protection profile search/sort parameters. Before allowing access to the
audit records, the AUD_PROC function uses the AUTH function to
authenticate the authorized administrator. All successful and unsuccessful
attempts by an authorized administrator to access/manage the audit
subsystem (in compliance with the ‘management of security functions
behavior’ stated in the CC requirements) are also audited.
The AUD_PROC function allows the authorized administrator to review
the audit records based on user identity, network addresses, ranges of
dates and times, and ranges of addresses. If the audit trail is full i.e.
maximum allowed disk utilization percentage is reached, the AUD_PROC
function initiates a controlled shut down of the TOE and all traffic flowing
through it. The controlled shutdown process is audited and results in the
complete switching-off (power-off) of the TOE and all traffic flowing
through it. Since the TOE is switched-off in a controlled manner when the
audit trail reaches the maximum allowed disk space, there is no loss of
audit trail data.
PF The PF function filters packets received from the INTERCEPT function
depending on rules selected by the PF_Rule_Select function.
The PF function discards any IP packets that are received on either an
internal or an external network interface in compliance with the common
criteria requirements for information control policy/functions mentioned
in the Protection Profiles used to instantiate this security target.
If these steps have not discarded the packet, the PF function interfaces
with the PF_Rule_Select function to find the packet filter rule to apply to
the packet. If no packet filter rule is found, the PF function discards the
packet. If a packet filter rule is found, the PF function applies the rule
found to the packet.
Depending upon the result of how the packet filter rules are applied to
corresponding packets, the PF decides if packets are dropped, passed
through, or passed to a proxy. If the packet is dropped, a destination
unreachable message will be sent only if indicated by the rule. The PF
function also participates in audit data generation by passing audit records
to the AUD_PROC function containing the results of all decisions
regarding information flow, and the presumed addresses of the source and
destination of the packets. The PF function passes packets to the
FTP_Proxy and Telnet_Proxy functions if the rule found indicates that the
packet should be passed to a proxy. An additional criterion that may be
specified in the packet filter rule is the list of senders and recipients to
whom the rule applies. The PF function interrogates the packet filter rules
to determine the senders and recipients to whom the rule applies and
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subsequently prompts the applicable proxy to identify a user via the
AUTH function.
PF_Rule_Select The PF_Rule_Select function shall be able to correctly determine
which rule from the Rule Set should be applied to all IP packets. For every
IP packet, the rule applied shall be the first found in the dynamic rule base
or the Rule Set that matches the source, destination, service, and protocol
characteristics of a given IP packet.
The rule set is established by the MGM function, and passed to the
PF_Rule_Select function. Source and destination addresses, service and
protocol, potential results and modifiers specify the rules. Source and
Destination addresses are specified by pairwise combinations of individual
hosts, subnets, or networks, the firewall itself, or all traffic via a specific
port. Service and protocol are specified by service/protocol pair, all
protocols, or ICMP. Potential results are one of permit, deny and proxy.
Modifiers include restrictions on port ranges, and enabling replies, which
allows a back-channel if attached to a permit result, and sends a
destination-unreachable if attached to a deny rule.
Telnet_Proxy The telnet service is an application that is typically used to allow a user to
log into a remote machine. This is done by allowing a user on a client
system to interactively start a login session on a remote system. Once the
login session is established the client process passes the input to the server
process, which performs the required tasks on the remote system, and
transmits the output back to the client. To protect against intruders,
‘CyberGuard Firewall/VPN version 6.2.1’ uses the Telnet_Proxy as a
more secure channel. When a connection is requested, the Telnet-Proxy
responds instead of the actual telnet service and since each connection
request is forwarded to the Telnet_Proxy running on the TOE it is not
possible for external hosts to access IP addresses of internal networks. The
AUTH function performs authentication and passes audit records to the
AUD_PROC function containing among other parameters the applicable
user identity, session ID and the sensor value19
. These parameters that are
used in the overall composition of the ‘Telnet Proxy’ related audit trail
records are made available to the AUTH and the AUD_PROC functions
by the Telnet_Proxy function. The Telnet_Proxy function also ensures that
the telnet protocol in use meets the generally accepted published protocol
definitions.
FTP_Proxy The FTP service is an application that is typically used to allow a user to
log into a remote machine. This is done by allowing a user on a client
system to interactively start a login session on a remote system. Once the
login session is established the client process passes the input to the server
process, which performs the required tasks on the remote system, and
transmits the output back to the client. To protect against intruders,
19
Sensor value contains the name of the sub-system that has generated the audit record.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
‘CyberGuard Firewall/VPN version 6.2.1’ uses an FTP_Proxy as a more
secure channel. When a connection is requested, the FTP_Proxy responds
instead of the actual ftp service and since each connection request is
forwarded to the FTP_Proxy running on the TOE it is not possible for
external hosts to access IP addresses of internal networks. The FTP_Proxy
function passes information through the TOE after requiring the user to
undergo Identification & Authentication using the AUTH function. The
AUTH function performs authentication and passes audit records to the
AUD_PROC function containing among other parameters the applicable
user identity, session ID and the sensor19
value. These parameters that are
used in the overall composition of the ‘FTP Proxy’ related audit trail
records are made available to the AUTH and the AUD_PROC functions
by the FTP_Proxy. The FTP_Proxy function also ensures that the FTP
protocol in use meets the generally accepted published protocol
definitions.
HTTP_Proxy Hypertext Transfer Protocol (HTTP) is the primary network protocol that
is used to transfer hypertext documents and related resources across the
Internet from servers to clients. The ‘CyberGuard Firewall/VPN version
6.2.1’ uses the HTTP_Proxy to secure an enterprise's HTTP traffic by
impersonating a server when communicating with a client and optionally
impersonating a client when communicating with a server. It does this by
intercepting HTTP packets going through the firewall and applying
redirection and filtering services to the packets. Redirection service allows
the HTTP_Proxy to allocate the identity of the actual server. Filtering
service allows the HTTP_Proxy to examine the contents of the HTTP
packets and secure the HTTP traffic flowing into and out of the networks.
The HTTP_Proxy can operate as a transparent or nontransparent proxy. If
operating as a transparent proxy, the HTTP_Proxy intercepts HTTP traffic
without the knowledge of HTTP clients (e.g., Web browsers). If operating
as a nontransparent proxy, the client is aware of the existence of the proxy
and connects directly to it or a virtual address handled by the proxy. The
HTTP_Proxy redirects the session to an actual server address. In this
mode, the HTTP_Proxy provides the additional capabilities of client
authentication.
The HTTP_Proxy function also ensures that the HTTP protocol in use
meets the generally accepted published protocol definitions and audits all
related information flow requests via the AUD_PROC function. These
audit records contain the presumed addresss of both the source and the
destination subjects.
SMTP_Proxy Simple Mail Transfer Protocol (SMTP) is a store-and-forward protocol
used by mail transfer agents20
to transfer electronic mail messages. The
20
A Mail Transfer Agent (MTA) is a service that examines an electronic mail message to determine who
the recipients are and how to forward the mail message to those recipients.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
‘CyberGuard Firewall/VPN version 6.2.1’ uses the SMTP_Proxy to
secure an enterprise's SMTP traffic by impersonating a server when
communicating with a client and optionally impersonating a client when
communicating with a server. It does this by intercepting SMTP packets
going through the firewall and applying redirection and filtering
mechanisms to the packets.
Via redirection the SMTP_Proxy allocates the identity of the actual server
at configuration time.
Via the filtering mechanism the SMTP_Proxy examines the contents of
the SMTP packets that flow between the client and server, it. This allows
the SMTP proxy to secure the SMTP traffic flowing into and out of the
networks at both a low level (i.e., mail connections and commands) and a
high level (i.e., mail headers, messages, and attachments). It allows the
SMTP_proxy to hide information about the internal networks by deleting
message headers and changing the mailboxes found in the message
headers.
The SMTP_Proxy function also ensures that the SMTP protocol in use
meets the generally accepted published protocol definitions and audits all
related information flow requests via the AUD_PROC function. These
audit records contain the presumed addresss of both the source and the
destination subjects.
AUTH The AUTH function provides the challenge and response for user
authentication. It supports username/password authentication as well as
the single-use authentication mechanism via the RSA Authentication
Manager 6.0. The function that requires authentication passes the identity
of the user to the AUTH function, which selects the appropriate type of
authentication for the user and application.
The TOE Authentication policy determines how the AUTH function will
authenticate the client of a network session. It is expressed with an ordered
list of authentication rules which are configured via the MGM function.
Each rule associates an authenticator (Radius, ‘single use’ Authenticator
or Internal, ‘multiple use’ Authenticator) with the conditions under which
to invoke that authenticator. These conditions include the rule’s service,
source, destination, and application condition categories.
A network session matches a rule only if it matches the rule's service,
source, destination, and application condition categories. A network
session matches a category if it matches any of the objects in the category.
The way in which a network session matches an object in a category
varies with the type of object. Generally, if an object specifies several
criteria, a network session must match all of those criteria
The AUTH function identifies the rule that a network session matches and
the authenticator associated with that rule. It then invokes the
authenticator. When an authenticator is invoked, it will succeed or fail
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
authentication. Network sessions related to the he ‘FTP_Proxy’ and the
‘Telnet_Proxy’ are assigned ‘Authentication Rules’ that have the ‘Radius
Authenticator’ (for single-use authentication) associated with them.
If a network session does not match any of the authentication rules, the
firewall invokes a special Deny authenticator that conducts an
authentication dialog but fails all authentication requests.
The AUTH function performs the authentication as described above and
returns the results to the calling function. The AUTH function locks the
user if there are excessive user authentication failures. The AUTH
function as mentioned above supports authentication requests from the
FTP_Proxy, Telnet_Proxy, and MGM functions.
The AUTH function interfaces with the MGM function to receive the lists
of users, authentication mechanisms and applications, the setting for how
many failures to allow, and to reset locked accounts. The AUTH function
passes audit records to the AUD_PROC function containing the user
identity, session GroupId, sensor value, authenticator type, and the results
of the attempt (i.e., either successful and unsuccessful) thereby forming
the source of authentication related audit trails to the AUD_PROC
function.
The single use authentication mechanism is in compliance with the
“Statistical random number generator tests” found in section 4.11.1 of
FIPS PUB 140-1 and the “Continuous random number generator test”
found in section 4.11.2 of FIPS PUB 140-1. The password authentication
mechanism requires a minimum of 8 character passwords. Each one of the
8 characters in the password is allowed any one of the following 95 ASCII
values:
32 sp 33 ! 34 " 35 # 36 $ 37 % 38 & 39 '
40 ( 41 ) 42 * 43 + 44 , 45 - 46 . 47 /
48 0 49 1 50 2 51 3 52 4 53 5 54 6 55 7
56 8 57 9 58 : 59 ; 60 < 61 = 62 > 63 ?
64 @ 65 A 66 B 67 C 68 D 69 E 70 F 71 G
72 H 73 I 74 J 75 K 76 L 77 M 78 N 79 O
80 P 81 Q 82 R 83 S 84 T 85 U 86 V 87 W
88 X 89 Y 90 Z 91 [ 92 \ 93 ] 94 ^ 95 _
96 ` 97 a 98 b 99 c 100 d 101 e 102 f 103 g
104 h 105 i 106 j 107 k 108 l 109 m 110 n 111 o
112 p 113 q 114 r 115 s 116 t 117 u 118 v 119 w
120 x 121 y 122 z 123 { 124 | 125 } 126 ~
Thus, there are 95^8 = 6,634,204,312,890,625 potential password
combinations implying that the probability that the authentication data can
be guessed is no greater than one in ninety five to the power eight (95 ^
8). This demonstrates that for password authentication the probability that
the authentication data can be guessed is even lower than the common
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
criteria requirements of one in two to the power forty (2^40 =
1,099,511,627,776) as specified in the Protection Profiles used to
instantiate this security target. The Strength of Function for the AUTH
function hence complies with SOF-medium.
MGM The MGM function provides the authorized administrator the ability to
manage the TOE. The MGM function via the GUI interface allows the
authorized administrator to configure, manage and review the TOE. It
also provides the authorized administrator the ability to setup queries to
view the audit trails stored in the audit sub-system via the GUI. The MGM
will force the user to authenticate by calling the AUTH function before
taking any action. The below mentioned items are managed through the
MGM function which also generates audit events for all management
control functions (which for example include, login, logout, system startup
and shutdown, user un-blacklisting etc.) and sends them to the
AUD_PROC function thereby contributing in the generation of
corresponding audit trail records.
A) Rules selected by the PF_Rule_Select function.
B) Time reported by the TIME function
C) User identities and assignment of those identities to the
authorized administrator roles.
D) Authentication mechanisms to be used by the AUTH
function.
E) Thresholds for reactions to authentication failure, used by
the AUTH function.
F) Unlocking accounts locked by the AUTH function.
G) Privileged and protected items for use by the IAC function.
H) Maximum allowed disk utilization percentage for audit
trails.
I) Controlled/Scheduled system startup and shutdown.
J) Audit Trail display and view.
Audit trails for all other functions are generated and stored via the
AUD_PROC function by their respective security functions.
Note:
The strength of function requirement applies to password authentication
mechanism. The related IT security function is AUTH. The Strength of
Function claim for the password authentication mechanism is SOF
Medium. Overall SOF requirement for the TSF, aside from the specific
Strength of Function claimed for the authentication function, is SOF-Medium. All TOE
security functions are implemented in accordance with a strength of SOF-Medium [CC1].
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6.2 TOE Security Function Rationale
Table 7 - demonstrates the correspondence between the security functional requirements
(from both PPs) identified in Sections 5.1 and the TOE security functions identified in
Section 6.1.
Table 7 - Mappings Between TOE SFRs and TOE Security Functions
TIME
INTERCEPT
REAPER
IAC
AUD_PROC
NAT
PF
PF_RULE_SELECT
TELNET_PROXY
FTP_PROXY
HTTP_Proxy
SMTP_Proxy
AUTH
MGM
FAU_GEN.1 X X X X X
FAU_SAR.1 X X
FAU_SAR.3 X X
FAU_STG.1 X
FAU_STG.4 X X X
FDP_IFC.1(1) X X X X X
FDP_IFC.1(2) X X X X X
FDP_IFF.1(1) X X X X X
FDP_IFF.1(2) X X X X X
FDP_RIP.1 X
FIA_AFL.1 X X
FIA_ATD.1 X
FIA_UAU.5 X X X X
FIA_UID.2 X X X X X
FMT_MOF.1(1) X X X
FMT_MOF.1(2) X X X
FMT_MSA.1(1) X X X
FMT_MSA.1(2) X X X
FMT_MSA.1(3) X X X
FMT_MSA.1(4) X X X
FMT_MSA.3 X X X
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TIME
INTERCEPT
REAPER
IAC
AUD_PROC
NAT
PF
PF_RULE_SELECT
TELNET_PROXY
FTP_PROXY
HTTP_Proxy
SMTP_Proxy
AUTH
MGM
FMT_MTD.1(1) X X X
FMT_MTD.1(2) X X X
FMT_MTD.2 X X X
FMT_SMR.1 X
FPT_RVM.1 X X
FPT_SEP.1 X
FPT_STM.1 X
6.2.1 FAU_GEN.1
In order to meet FAU_GEN.1 the TSF must generate an audit record of a listed set of
auditable events, with additional information as required to meet the SFR. The TOE
Security function that processes the auditable event generates the audit record, and sends
it to the AUD_PROC function for processing. All audit records include identity of the
subject that caused the event, the outcome of the event, and the date and time of the
event, as reported by the TIME function. The following table lists the events required and
the TSF that is the source of the event, and the additional information in the audit record.
This additional information meets the requirements for the additional audit record
contents in Table 5 - above.
Table 8 - TSF Sources of Audit Data
Functional
Component
Auditable Event TSF Source
Additional Audit
Record Contents
FDP_IFF.1 All decisions on requests
for information flow.
PF The presumed
addresses of the
source and
destination subject.
FMT_SMR.1 Modifications to the group
of users that are part of the
authorized administrator
role.
Unsuccessful attempts to
authenticate the authorized
MGM The identity of the
authorized
administrator
performing the
modification and the
user identity being
associated with the
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Functional
Component
Auditable Event TSF Source
Additional Audit
Record Contents
administrator role. authorized
administrator role.
FIA_UID.2 All use of the user
identification mechanism.
AUTH The user identities
provided to the
TOE.
FIA_UAU.5 The final decision on
authentication.
AUTH The user identitiy
and the success or
failure of the
authentication.
FIA_AFL.1 The reaching of the
threshold for unsuccessful
authentication attempts and
the subsequent restoration
by the authorized
administrator of the user’s
capability to authenticate.
AUTH and MGM The identity of the
offending user and
the authorized
administrator.
FMT_STM.1 Changes to the time. MGM The identity of the
authorized
administrator
performing the
operation.
FMT_MOF.1 Use of the functions listed
in this requirement
pertaining to audit.
AUD_PROC The identity of the
authorized
administrator
performing the
operation.
6.2.2 FAU_SAR.1
In order to meet FAU_SAR.1, the TSF must provide the authorized administrator the
ability to review the audit data. The AUD_PROC function provides this ability via the
graphical user interfaces of the MGM function.
6.2.3 FAU_SAR.3
In order to meet FAU_SAR.3, the TSF must provide the ability to perform searches and
sorting of audit data based on user identity, presumed addresses, ranges of dates, times
and addresses. This function is provided through the AUD_PROC function, and is
accessible via the graphical user interfaces of the MGM function.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
6.2.4 FAU_STG.1
In order to meet FAU_STG.1, the TSF must protect audit records from unauthorized
deletion or any modification. The IAC function protects the records from unauthorized
deletion or any modification.
6.2.5 FAU_STG.4
When the audit trail is full, the AUD_PROC function contacts the MGM function, which
shuts down the TOE to prevent future auditable events. This addresses the requirement to
prevent loss of audit data, which is FAU_STG.4. If the audit trail is full i.e. maximum
allowed disk utilization percentage is reached, the AUD_PROC function initiates a
controlled shut down of the TOE and all traffic flowing through it. The controlled
shutdown process is audited and results in the complete switching-off (power-off) of the
TOE and all traffic flowing through it. Since the TOE is switched-off in a controlled
manner when the audit trail reaches the maximum allowed disk space, there is no loss of
audit trail data. The IAC function, which enforces roles and credentials to provide
separation of data and processes, is responsible for ensuring that only the AUD_PROC
function can initiate the shutdown of the TOE in the event the audit trail reaches the
maximum allowed disk space.
6.2.6 FDP_IFC.1(1)21
In order to meet FDP_IFC.1 (1), the TSF must enforce the UNAUTHENTICATED_SFP
that covers the exchange of information between unauthenticated external IT entities
through the TOE. The NAT and PF functions in conjunction with the ‘SMTP_Proxy’
and the ‘HTTP_Proxy’ addresses this requirement by enforcing the rules provided by the
PF_Rule_Select function on IP packets passed through the TOE.
6.2.7 FDP_IFC.1(2)22
In order to meet FDP_IFC.1 (2), the TSF must enforce the AUTHENTICATED_SFP that
covers the exchange of information between authenticated external IT entities through the
TOE. The NAT & PF functions in conjunction with the ‘Telnet_Proxy’ and the
‘FTP_Proxy’ addresses this requirement by enforcing the rules provided by the
PF_Rule_Select function on IP packets passed through the TOE.
21
The unauthenticated information flow control policy (UNAUTHENTICATED _SFP) is collectively
enforced by the FDP_IFC.1 (1) & FDP_IFF.1 (1) functional components. While, the FDP_IFC.1 (1)
functional component at a high level lists the entities [namely: ‘subjects’, ‘information flow control’ and
‘operation’] on which the SFP applies, the corresponding FDP_IFF.1 (1) functional component defines the
attributes for these entities. Hence all security functions that satisfy the FDP_IFC.1 (1) must also satisfy
FDP_IFF.1 (1).
22
The authenticated information flow control policy (AUTHENTICATED _SFP) is collectively enforced
by the FDP_IFC.1 (2) & FDP_IFF.1 (2) functional components. While, the FDP_IFC.1 (2) functional
component at a high level lists the entities [namely: ‘subjects’, ‘information flow control’ and ‘operation’]
on which the SFP applies, the corresponding FDP_IFF.1 (2) functional component defines the attributes for
these entities. Hence all security functions that satisfy the FDP_IFC.1 (2) must also satisfy FDP_IFF.1 (2).
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6.2.8 FDP_IFF.1 (1)21
In order to meet FDP_IFF.1 (1) the TSF must enforce a set of rules over the information
flows. The rules cover cases where information flow is always denied, and allow for the
administrator to set rules that accept information flows. The PF function denies
information flow by discarding packets. The element FPD_IFF.1.6 requires the TSF to
prevent information flow if the addressing makes it unlikely that the packet would have
been routed to the TOE. These cases are handled by the PF, HTTP_Proxy &
SMTP_Proxy security functions. The rules that explicitly allow information flows,
described in FDP_IFF.1.2, are implemented by the PF_Rules_Select function, which
implements the rules that allow information flow.
The element FDP_IFF.1.2 also requires the TSF to:
o Permit subjects on an internal network to cause information flow through the TOE to
another connected network if the presumed address of the source subject translates to
an internal address.
o Permit subjects on external network to cause information flow through the TOE to
another connected network: if the presumed address of the source subject, in the
information, translates to an external network address and the the presumed address of
the destination subject, in the information, translates to an address on the other
connected network.
These cases are handled by the NAT security function.
6.2.9 FDP_IFF.1 (2)22
In order to meet FDP_IFF.1 (2) the TSF must enforce a set of rules over the information
flows. The rules cover cases where information flow is always denied, and allow for the
administrator to set rules that accept information flows. The PF function denies
information flow by discarding packets. The element FPD_IFF.1.6 requires the TSF to
prevent information flow if the addressing makes it unlikely that the packet would have
been routed to the TOE. These cases are handled by the PF, FTP_Proxy and
Telnet_Proxy functions. The rules that explicitly allow information flows, described in
FDP_IFF.1.2, are implemented by:
o The PF_Rule_Select function, which implements the rules that allow information flow.
o The FTP_Proxy and Telnet_Proxy functions that ensure that human users initiating
information flow through the TOE are authenticated according to FIA_UAU.5.
The element FDP_IFF.1.2 also requires the TSF to:
o Permit subjects on an internal network to cause information flow through the TOE to
another connected network if the presumed address of the source subject translates to
an internal address.
o Permit subjects on external network to cause information flow through the TOE to
another connected network: if the presumed address of the source subject, in the
information, translates to an external network address and the the presumed address of
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
the destination subject, in the information, translates to an address on the other
connected network.
These cases are handled by the NAT security function.
6.2.10 FDP_RIP.1
In order to meet FDP_RIP.1, the TSF must ensure that information content of resources
used by the TOE is made unavailable upon the allocation of the resources. The REAPER
function implements this requirement by clearing all information from all memory
resources upon release of the resource. Since the resource is cleared before release, it
remains clear when the resource needs to be allocated again.
6.2.11 FIA_AFL.1
In order to meet FIA_AFL.1, the TSF must detect when a configured number of
unsuccessful authentication attempts have been made by a user, and then lock that user
out until the authorized administrator takes action. The limit on the number of failed
events, and the actions to allow a user access again are implemented by the MGM
function. The AUTH function counts the number of failures and locks the user out if the
number exceeds that established by the MGM function.
6.2.12 FIA_ATD.1
In order to meet FIA_ATD.1, the TSF must maintain an association between users and
the security attributes of identity, authorized administrator role, and proxy user. This list
is established and maintained by the MGM function
6.2.13 FIA_UAU.5
In order to meet FIA_UAU.5
o The TSF must successfully authenticate a user before allowing that user administrative
or proxy access. This requirement is met in each function that requires authentication:
Telnet_Proxy, FTP_Proxy, and MGM, by calling the AUTH function before allowing
any action by the users.
o The TSF must also provide password and single-use authentication mechanisms, and
use single-use authentication for FTP and Telnet authentication. The AUTH function
implements the password and single-use authentication mechanisms, and maintains a
list of which authentication mechanisms are appropriate for each types of access. Note
that the TOE does not include remote administration, or remote access by authorized IT
entities and hence does not claim single use authentication of authorized administrator
and IT entities .
6.2.13.1 FIA_UAU.5 Strength of Function
In order to meet the strength of function requirements for FIA_UAU.5 single-use
authentication mechanisms must be in compliance with the “Statistical random number
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
generator tests” found in section 4.11.1 of FIPS PUB 140-1 and the “Continuous random
number generator test” found in section 4.11.2 of FIPS PUB 140-1. Strength of function
shall be demonstrated for the password authentication mechanism such that the
probability that authentication data can be guessed is no greater than one in two to the
fortieth (2^40).
Strength of function for single-use authentication mechanisms can be demonstrated by
the effective bit strength of the packet. For single use authentication the TOE includes the
‘RSA Authentication Manager version 6.0’. The effective bit strength of the packet is as
follows:
8 character (Alpha/Numeric) PIN = 41.3 bits
6 digit token = 19.8 bits
Total bit strength = 61.1 bits or 1 in 2,471,341,346,050,066,508
Strength of function for the password authentication mechanisms can be demonstrated by
the following calculation: Passwords are required to be a minimum of 8 characters,
which can be each by one of 95 values (any upper case or lower case letter, any digit, and
all punctuation marks). The chance of guessing a password is therefore 1 in ninety-five
to the power eight (95^8), which is even less than the recommended one in two to the
fortieth (2^40). The Strength of Function for the AUTH function hence complies with
SOF-medium.
6.2.14 FIA_UID.2
In order to meet FIA_UID.2, the TSF must require each user to identify itself before
allowing any other TSF-mediated access. For services that require authentication, MGM,
Telnet_Proxy, and FTP_Proxy, the function prompts for identity before calling the
AUTH function, which occurs before any actions by that function. For normal packet
transfer, the presumed identity of the external IT entity is carried in the source and
destination addresses of the packet.
6.2.15 FMT_MOF.1 (1)
In order to meet FMT_MOF.1(1), the TSF must restrict the ability to enable or disable
the TOE and the single-use authentication functions to the authorized administrator. The
MGM function enforces this restriction by requiring the user to successfully authenticate
as an authorized administrator, via the AUTH function, before accessing any
administrative functions. The IAC function protects modification of these functions by
any function except for the MGM function acting on behalf of an authorized
administrator.
6.2.16 FMT_MOF.1 (2)
In order to meet FMT_MOF.1(2), the TSF must restrict the ability to enable, disable, or
modify the behavior of audit trail management, and backup and restore for TSF data to
the authorized administrator. The MGM function enforces this restriction by requiring
the user to successfully authenticate as an authorized administrator, via the AUTH
function, before accessing any administrative functions. The IAC function protects
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
modification of these functions by any function except for the MGM function acting on
behalf of an authorized administrator.
6.2.17 FMT_MSA.1(1)
In order to meet FMT_MSA.1(1) the TSF must restrict the ability to add, modify, or
delete attributes in the unauthenticated SFP information flow control rules to the
authorized administrator. The IAC function ensures that only the MGM function can
add, delete, or modify the attributes, and the MGM function accesses the AUTH function
to ensure that only authorized administrator are allowed to perform any administration.
6.2.18 FMT_MSA.1(2)
In order to meet FMT_MSA.1(2) the TSF must restrict the ability to add, modify, or
delete attributes in the authenticated SFP information flow control rules to the authorized
administrator. The IAC function ensures that only the MGM function can add, delete, or
modify the attributes, and the MGM function accesses the AUTH function to ensure that
only authorized administrator are allowed to perform any administration.
6.2.19 FMT_MSA.1(3)
In order to meet FMT_MSA.1(1) the TSF must restrict the ability to create or delete
unauthenticated SFP information flow control rules to the authorized administrator. The
IAC function ensures that only the MGM function can create or delete rules, and the
MGM function accesses the AUTH function to ensure that only authorized administrator
are allowed to perform any administration.
6.2.20 FMT_MSA.1(4)
In order to meet FMT_MSA.3(2) the TSF must restrict the ability to create or delete
authenticated SFP information flow control rules to the authorized administrator. The
IAC function ensures that only the MGM function can create or delete the rules, and the
MGM function accesses the AUTH function to ensure that only authorized administrator
are allowed to perform any administration.
6.2.21 FMT_MSA.3
In order to meet FMT_MSA.3, the TSF must provide restrictive default values for
information flow control security attributes, and allow the authorized administrator to set
different default values. The PF function implements a default of deny for any packets
for which PF_Rule_Select cannot find a rule. An authorized administrator can override
this by using MGM to create a rule for PF_Rule_Select that refers to all addresses. The
MGM function accesses the AUTH function to ensure that only authorized administrator
are allowed to perform any administration.
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6.2.22 FMT_MTD.1 (1)
In order to meet FMT_MTD.1(1), the TSF must restrict the ability to query, modify, or
delete the association of users to authorized administrator roles to the authorized
administrators. The IAC function ensures that only the MGM function can query,
modify, or delete the association between users and authorized administrators. The MGM
function accesses the AUTH function to ensure that only authorized administrators are
allowed to perform any administration.
6.2.23 FMT_MTD.1 (2)
In order to meet FMT_MTD.1(2), the TSF must restrict the ability to set the date and
time used to form timestamps to the authorized administrators. The IAC function ensures
that only the MGM function can set the date and time used to form timestamps. The
MGM function accesses the AUTH function to ensure that only authorized administrators
are allowed to perform any administration.
6.2.24 FMT_MTD.2
In order to meet FMT_MTD.2, the TSF must restrict the ability to specify limits on failed
authentication attempts to the authorized administrator, and lock users who exceed those
limits. The AUTH function enforces limits on failed authentication attempts passed to it
by the MGM function. The IAC function ensures that only the MGM function can
change those limits. The MGM function accesses the AUTH function to ensure that only
users that authenticate as authorized administrator can perform any administration.
6.2.25 FMT_SMR.1
In order to meet FMT_SMR.1, the TSF must maintain the role of authorized
administrator and associate human users with that role. The MGM function maintains the
role of authorized administrator, and associates users with that role.
6.2.26 FPT_RVM.1
In order to meet FPT_RVM.1, the TSF must ensure that enforcement functions are
invoked and succeed before allowing data to pass. The INTERCEPT function forces all
packets to be passed through to be evaluated by the enforcement functions, specifically
the PF function, before allowing the packet to pass. Also, the MGM function ensures that
the TOE configuration is successfully applied by the system administrator before any
data traffic is allowed to be passed.
6.2.27 FPT_SEP.1
In order to meet FPT_SEP.1, the TSF must maintain a domain for its execution that
protects it from interference by non-TSF functions, must enforce separation between the
security domains of subject in the TSC. The IAC function provides separation between
the security domains in the system. Separate domain are maintained for each TSF, for
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subjects acting on behalf of authorized administrator, and other subjects that may be
present on the TOE, or it's CGLinux host.
6.2.28 FPT_STM.1
In order to meet FPT_STM.1, the TSF must be able to provide reliable timestamps for its
own use. The TIME function maintains the reliable timestamps that are used by the TOE
internally, such as to stamp the audit records.
6.3 Assurance Measures
The TOE stresses assurance through vendor actions that are within the bounds of current
best commercial practice. The TOE provides, primarily via review of vendor-supplied
evidence, independent confirmation that these actions have been competently performed,
and independent analysis and testing.
The general level of assurance for the TOE is:
A) Consistent with current best practice for IT development and provides a
product that is competitive against other evaluated products with respect to
functionality, performance, cost, and time-to-market.
B) The TOE assurance also meets current constraints on widespread
acceptance, by expressing its claims against EAL4 from part 3 of the
Common Criteria.
Table 9 - demonstrates the correspondence between the security assurance requirements
listed in Sections 5.2 to the developer evidence.
Table 9 - Assurance Correspondence
Assurance Class Component ID Documentation
ACM_AUT.1 (Partial CM
automation)
Configuration Management
ACM_CAP.4 (Generation
support and acceptance
procedures)
The CM documentation
describes the processes and
procedure that are followed and
automated tools that
are utilized in the tracking and
monitoring the changes to the
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Assurance Class Component ID Documentation
ACM_SCP.2 (Problem tracking
CM coverage)
CM items and the generation of
the TOE. The configuration
management measures applied
by CyberGuard ensure that
configuration items are
uniquely identified. CyberGuard
ensures that changes to the
implementation representation
are controlled and
that TOE associated
configuration item modifications
are properly controlled.
CyberGuard performs
configuration management on
the TOE implementation
representation, design, tests,
user and administrator
guidance, and the CM
documentation.
ADO_DEL.2 (Detection of
modification)
Delivery and Operation
ADO_IGS.1 (Installation,
Generation, and Start-Up
Procedures)
CyberGuard provides delivery
documentation and
procedures to identify the
TOE, allow detection of
unauthorized modifications of
the TOE and installation and
generation instructions at
start-up. CyberGuard’s
delivery procedures describe
the procedures to be used for
the secure installation,
generation, and start-up of
the TOE.
ADV_FSP.2 (Fully Defined
External Interfaces)
CyberGuard provides design
documentation that identifies
and describes the external
interfaces and the
decomposition of the TOE
into subsystems.
ADV_HLD.2 (Security Enforcing
High-Level Design)
The CyberGuard High Level
Design, and its references,
group the TOE into
subsystems and describe
how the subsystems behave
and interact with each other.
Development
ADV_IMP.1 (Subset of the
Implementation of the TSF)
The Cyberguard FSP, HLD and
TAT documents collectively
satisy this requirement.
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Assurance Class Component ID Documentation
ADV_LLD.1 (Descriptive Low-
Level design)
TheCyberGuard Low-level
Design Specification satisfies
the requirement to
decompose each subsystem
into modules and fully
describes each module.
ADV_RCR.1 (Informal
Correspondence Demonstration)
This informal correspondence
demonstration is done by
mapping Security Functions,
SFRs, TOE SubSystems &
Modules and appropriate Test
cases in the CyberGuard FSP
document.
ADV_SPM.1 (Informal TOE
security policy model)
The SPM environment is met by
configuring the product as per
the documentation provided in
this ST.
AGD_ADM.1 (Administrator
Guidance)
Guidance Documents
AGD_USR.1 (User Guidance)
CyberGuard provides
administrator guidance on
how to utilize the TOE
security functions and
warnings to
authorized administrators
about actions that can
compromise the security of
the TOE. The installation and
generation procedures,
included in the administrator
guidance, describe the steps
necessary to install
CyberGuard appliances in
accordance with the
evaluated configuration. This
is done via the administrator
and user guidance
documents
ALC_DVS.1 (Identification of
security measures)
Life Cycle Support
ALC_LCD.1 (Developer defined
life-cycle model)
CyberGuard ensures the
adequacy of the procedures
used during the development
and maintenance of the
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Assurance Class Component ID Documentation
ALC_TAT.1 (Well-defined
development tools)
TOE through the use of a
comprehensive life-cycle
management plan.
CyberGuard includes security
controls on the development
environment that are
adequate to provide the
confidentiality and integrity of
the TOE design and
implementation that is
necessary to ensure the
secure operation of the TOE.
CyberGuard achieves
this through the use of a
documented model of the
TOE life-cycle and well-
defined development tools
that yield consistent and
predictable results.
CyberGuard has procedures
for accepting and addressing
identified operational flaws as
well as security flaws,
including tracking of all
identified flaws, describing,
correcting, and taking other
remedial actions such as
producing guidance related to
such flaws.
ATE_COV.2 (Analysis of
Coverage)
ATE_DPT.1 (Testing: high-level
design)
ATE_FUN.1 (Functional Testing)
Tests
ATE_IND.2 (Independent Testing
- Sample)
CyberGuard provides test
documentation that describes
how each of the TOE security
functions is tested, as
well as the actual results of
applying the tests. The
documentation shall contain the
following:
o The test case descriptions
o Test Plan
AVA_MSU.2 (Validation of
analysis)
AVA_SOF.1 (Strength of TOE
Security Function Evaluation)
Vulnerability Assessment
AVA_VLA.2 (Independent
Vulnerability Analysis)
CyberGuard has a documented
process of tracking and
remedying all vulnerabilities that
are reported via various sources
to maintain TOE in a secure
state.
Flaw Remediation* ALC_FLR.3 (Systematic Flaw
Remediation)
CyberGuard comprehensively
documents the method and
procedures it has in place to
track all flaws. These flaws are
assigned a priority based on
several criteria (For example
whether or not the flaw is
security relevant). Based on a
priority level assigned to a flaw
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CyberGuard Firewall/VPN Version 6.2.1 Security Target
Assurance Class Component ID Documentation
they are rectified/remedied in a
timely fashion.
*NOTE:
The ALC_FLR.3, Systematic Flaw Remediation was added to augment the EAL4 level of
evaluation .This augmentation, which is in line with the robust ‘Software Development
Life Cycle (SDLC)’ model already being followed by the TOE developer, was included
due to the strong consumer demand that the developer be able to systematically receive
security flaw reports, fix security flaws and dispatch corrective fixes to the TOE users in
a systematic, secure and a timely manner.
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CHAPTER 7
7. Protection Profile Claims
This ST is CC Part 2 [CC2] conformant and CC Part 3 [CC3] conformant for EAL4. This
ST does not claim conformance with any Protection Profile.
There are no explicitly stated IT security requirements that are not in [CC2].
7.1 Protection Profile Reference
The CyberGuard Firewall/VPN Version 6.2.1 has been modeled23
on the following two
Protection Profiles:
Final U.S. Department of Defense Application-Level Firewall Protection Profile for
Medium Robustness Environments, Version 1.0, June 28, 2000
Final U.S. Department of Defense Traffic-Filter Firewall Protection Profile for
Medium Robustness Environments, Version 1.4, May 1, 2000
23
Albeit the CyberGuard Firewall/VPN version 6.2.1 has been modeled on the TF-MRPP & AP-MRPP it
does not claim conformance to either.
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CHAPTER 8
8. Rationale
The set of IT security requirements together forms a mutually supportive whole. For each active
security function, the requirements that support and protect that function are also present in the
profile.
The IT security functions work together to satisfy the TOE security functional requirements.
Each security function contributes to satisfying the SFRs.
8.1 Security Objectives Rationale
Table 10 - demonstrates the correspondence between the security objectives listed in Sections 4.1
and 4.2 to the assumptions, threats and policies identified in Sections 3.2, 3.3 and 3.4.
Table 10 - Environmental Security Objectives, Assumptions/Threats Mappings
T.E.TUSAGE
A.SINGEN
A.DIRECT
A.NOREMO
A.REMACC
A.MODEXP
A.NOEVIL
A.TRAIN
A.PHYSEC
A.GENPUR
A.PUBLIC
O.E.SINGEN X
O.E.DIRECT X
O.E.NOREMO X
O.E.REMACC X
O.E.MODEXP X
O.E.ADMTRA X X
O.E.PHYSEC X
O.E.GENPUR X
O.E.GUIDAN X
O.E.NOEVIL X
O.E.PUBLIC X
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Table 11 - Mappings Between IT Security Objectives, and Threats
T.NOAUTH
T.REPEAT
T.REPLAY
T.ASPOOF
T.MEDIAT
T.OLDINF
T.AUDACC
T.SELPRO
T.AUDFUL
T.MODEXP
O.IDAUTH X
O.SINUSE X X
O.MEDIAT X X X
O.SECSTA X X
O.SELPRO X X X
O.AUDREC X
O.ACCOUN X
O.SECFUN X X X
O.LIMEXT X
O.EAL X
8.1.1 Rationale for TOE Security Objectives
8.1.1.1 T.NOAUTH
T.NOAUTH is the threat that an unauthorized person may attempt to bypass the security of the
TOE so as to access and use security function and/or non-security functions provided by the
TOE. This threat is addressed by O.IDAUTH, O.SECSTA, O.SELPRO, O.SECFUN and
O.LIMEXT. Collectively these security objectives counter the threat (T.NOAUTH) by ensuring
that the TOE does the following:
o Uniquely identify and authenticate the claimed identity of all users, before granting a user
access to the TOE functions or, for certain specified services to a connected network.
o Ensure that upon initial start-up of the TOE or recovery from an interruption in the TOE
service, the TOE must not compromise its resources or those of any connected network.
o Ensure that the TOE protects itself against attempts by unauthorized users to bypass,
deactivate, or tamper with TOE security functions.
o Guarantee that it (the TOE) provides functionality that enables an authorized
administrator to use the TOE security functions, and must ensure that only the authorized
administrators are able to access such functionality.
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o Guarantee that it (the TOE) provides the means for an authorized administrator to control
and limit access to the TOE security functions by an authorized external IT entity.
8.1.1.2 T.REPEAT24
T.REPEAT is the threat that an unauthorized person may repeatedly try to guess authentication
data in order to use this information to launch attacks on the TOE. This threat (T.REPEAT) is
countered by the O.SINUSE security objective, which ensures that the TOE does the following:
o Guarantee that it (the TOE) prevents the reuse of authentication data for users attempting
to authenticate to the TOE from a connected network.
8.1.1.3 T.REPLAY25
T.REPLAY is the threat that an unauthorized person may use valid identification and
authentication data obtained to access functions provided by the TOE. This threat is addressed by
O.SINUSE, O.SECFUN. These TOE security objectives counter the threat (T.REPLAY).
The TOE security objectives, O.SINUSE and O.SECFUN, ensure that the TOE does the
following:
o Guarantee that it (the TOE) prevents the reuse of authentication data for users attempting
to authenticate to the TOE from a connected network.
o Guarantee that it (the TOE) provides functionality that enables an authorized
administrator to use the TOE security functions, and must ensure that only the authorized
administrators are able to access such functionality.
8.1.1.4 T.ASPOOF
T.SPOOF is the threat that an unauthorized person on an external network may attempt to bypass
the information flow control policy by disguising authentication data (e.g., spoofing the source
address) and masquerading as a legitimate user or entity on an internal network. This threat
(T.ASPOOF) is countered by the O.MEDIAT security objective, which ensures that the TOE
does the following:
o Ensure that it (the TOE) mediates the flow of all information between clients and servers
located on internal and external networks governed by the TOE or from users on a
connected network to users on another connected network. It (The TOE) also ensures that
residual information from a previous information flow is not transmitted in any way.
8.1.1.5 T.MEDIAT
T.MEDIAT is the threat that an unauthorized person may send impermissible information
through the TOE, which results in the exploitation of resources on the internal network. This
24
Since the TOE does not claim remote administration T.REPEAT is not applicable to the TOE for authenticating a
remote administrator. However, this threat is mitigated via single use authentication of proxy users.
25
Since the TOE does not claim remote administration T.REPLAY is not applicable to the TOE for authenticating a
remote administrator. However, this threat is mitigated via single use authentication of proxy users.
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threat (T.MEDIAT) is countered by O.MEDIAT security objective, which ensures that the TOE
does the following:
o Ensure that it (the TOE) mediates the flow of all information between clients and servers
located on internal and external networks governed by the TOE or from users on a
connected network to users on another connected network. It (The TOE) also ensures that
residual information from a previous information flow is not transmitted in any way.
8.1.1.6 T.OLDINF
T.OLDINF is the threat that, because of a flaw in the TOE functioning, may allow an
unauthorized person to gather residual information from a previous information flow or internal
TOE data by monitoring the padding of the information flows from the TOE. This threat
(T.OLDINF) is countered by O.MEDIAT security objective, which ensures that the TOE does
the following:
o Ensure that it (the TOE) mediates the flow of all information between clients and servers
located on internal and external networks governed by the TOE or from users on a
connected network to users on another connected network. It (The TOE) also ensures that
residual information from a previous information flow is not transmitted in any way.
8.1.1.7 T.AUDACC
T.AUDACC is the threat that allows persons not to be accountable for the actions that they
conduct because the audit records are not reviewed, thus allowing an attacker to escape. This
threat (T.AUDACC) is addressed by O.AUDREC and O.ACCOUN. Collectively these security
objectives counter the threat (T.AUDACC) by ensuring that the TOE does the following:
o Ensure that it (the TOE) provides a means to record a readable audit trail of security-
related events, with accurate dates and times, and a means to search and sort the audit
trail based on relevant attributes.
o Ensure that it (the TOE) provides user accountability for information flows through the
TOE and for authorized administrator use of security functions related to audit.
8.1.1.8 T.SELPRO
T.SELPRO is the threat that allows an unauthorized person read, modify, or destroy security
critical TOE configuration data. This threat (T.SELPRO) is addressed by O.SECSTA and
O.SELPRO. Collectively these security objectives counter the threat (T.SELPRO) by ensuring
that the TOE does the following:
o Ensure that upon initial start-up of the TOE or recovery from an interruption in the TOE
service, the TOE must not compromise its resources or those of any connected network.
o Ensure that the TOE protects itself against attempts by unauthorized users to bypass,
deactivate, or tamper with TOE security functions.
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8.1.1.9 T.AUDFUL
T.AUDFUL is the threat that allows an unauthorized person to cause audit records to be lost or
prevent future records from being recorded by taking actions to exhaust audit storage capacity,
thus masking an attackers actions. This threat (T.AUDFUL) is addressed by O.SELPRO and
O.SECFUN. Collectively these security objectives counter the threat (T.AUDFUL) by ensuring
that the TOE does the following:
o Ensure that the TOE protects itself against attempts by unauthorized users to bypass,
deactivate, or tamper with TOE security functions.
o Guarantee that it (the TOE) provides functionality that enables an authorized
administrator to use the TOE security functions, and must ensure that only the authorized
administrators are able to access such functionality.
8.1.1.10 T.MODEXP
T.MODEXP is the threat of malicious attacks aimed at discovering exploitable vulnerabilities
and is considered medium. This threat (T.MODEXP) is countered by the O.EAL26
security
objective, which ensures that the TOE does the following:
o Guarantee that it (the TOE) be structurally tested and shown to be resistant to obvious
vulnerabilities.
26
The security objective O.EAL is not met by any SFRs in the ST, however this objective is met by the EAL 4
Security Assurance Requirements mentioned in the ‘TOE Security Assurance Requirements’ section of the ST.
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8.1.2 Rationale for IT Environment Security Objectives
8.1.2.1 T.E.TUSAGE
T.E.TUSAGE is the threat that the TOE may be inadvertently configured, used, and administered
in an insecure manner by either authorized or unauthorized persons. This threat is addressed by
O.E.GUIDAN, which ensures that the TOE is to be delivered, installed, administered, and
operated in a manner that maintains security, and O.E.ADMTRA which ensures that
administrators that proper training to ensure that correct operation continues.
8.1.2.2 A.SINGEN
If O.E.SINGEN is achieved, then information cannot flow between the internal and external
networks without passing though the TOE, which is A.SINGEN.
8.1.2.3 A.DIRECT
If O.E.DIRECT is achieved, then human users within the physically secure boundary protecting
the TOE may attempt to access the TOE from some direct connection (e.g., a console port) if the
connection is part of the TOE, which is A.DIRECT.
8.1.2.4 A.NOREMO
If O.E.NOREMO is achieved, then human users who are not authorized administrators cannot
access the TOE remotely from the internal or external networks, which is A.NOREMO.
8.1.2.5 A.REMACC
If O.E.REMACC is achieved, then authorized administrators may only access the TOE locally,
which is A.REMACC.
8.1.2.6 A.MODEXP
If O.E.MODEXP is achieved, then the threat of malicious attacks aimed at discovering
exploitable vulnerabilities is considered medium, which is A.MODEXP.
8.1.2.7 A.NOEVIL
If O.E.NOEVIL is achieved, then authorized administrators are non-hostile and follow all
administrator guidance; however, they are capable of error, which is A.NOEVIL.
8.1.2.8 A.TRAIN
If O.E.ADMTRA is achieved, then Firewall Administrators are trained as to the establishment of
security policies and practices, which ensures that they are familiar with the various Sub-Systems
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CyberGuard Firewall/VPN Version 6.2.2 Security Target
of the TOE’s Management Software and are able to implement the site’s security policy, which
is A.TRAIN.
8.1.2.9 A.PHYSEC
If O.E.PHYSEC is achieved, then the TOE is physically secure, which is A.PHYSEC.
8.1.2.10 A.GENPUR
If O.E.GENPUR is achieved, then there are no general-purpose computing capabilities (e.g., the
ability to execute arbitrary code or applications) and storage repository capabilities on the TOE,
which is A.GENPUR.
8.1.2.11 A.PUBLIC
If O.E.PUBLIC is achieved, then the TOE does not host public data, which is A.PUBLIC.
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8.2 Security Requirements Rationale
8.2.1 Security Functional Requirements Rationale for the TOE
Table 12 - demonstrates the correspondence between the security objectives listed in Sections 4.1
to the security functional requirements (from both PPs) identified in Sections 5.1.
Table 12 - Mappings Between TOE Security Objectives and TOE SFRs
O.IDAUTH
O.SINUSE
O.MEDIAT
O.SECSTA
O.SELPRO
O.AUDREC
O.ACCOUN
O.SECFUN
O.LIMEXT
FAU_GEN.1 X X
FAU_SAR.1 X
FAU_SAR.3 X
FAU_STG.1 X X X
FAU_STG.4 X X X
FDP_IFC.1 (1) X
FDP_IFC.1 (2) X
FDP_IFF.1 (1) X
FDP_IFF.1 (2) X
FDP_RIP.1 X
FIA_ATD.1 X X
FIA_AFL.1 X
FIA_UAU.5 X X
FIA_UID.2 X X
FMT_MOF.1 (1) X X X
FMT_MOF.1 (2) X X X
FMT_MSA.1 (1) X X X
FMT_MSA.1 (2) X X X
FMT_MSA.1 (3) X X X
FMT_MSA.1 (4) X X X
FMT_MSA.3 X X X
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O.IDAUTH
O.SINUSE
O.MEDIAT
O.SECSTA
O.SELPRO
O.AUDREC
O.ACCOUN
O.SECFUN
O.LIMEXT
FMT_MTD.1 (1) X
FMT_MTD.1 (2) X
FMT_MTD.2 X
FMT_SMR.1 X
FPT_RVM.1 X X
FPT_SEP.1 X
FPT_STM.1 X
8.2.1.1 O.IDAUTH
In order to implement O.IDAUTH, the TOE must uniquely identify and authenticate the claimed
identity of all users, before granting a user access to TOE functions or, for certain specified
services, to a connected network. This is implemented by requiring user identification before any
action (FIA_UID.2), allowing limited actions before authentication, authentication mechanisms
(FIA_UAU.5), and binding the user identity to security attributes (FIA_ATD.1). Together these
SFRs combine to address the objective to uniquely identify and authenticate users, which is
O.IDAUTH.
8.2.1.2 O.SINUSE27
In order to implement O.SINUSE, the TOE must prevent the reuse of authentication data for
users attempting to authenticate to the TOE from a connected network. Also the TOE must
prevent the reuse of authentication data so that even if valid authentication data is obtained, it
will not be used to mount an attack. The TOE implements this requirement by specifying single-
use authentication mechanisms in FIA_UAU.5 and user attribute definition FIA_ATD.1. Note
27
As explicitly stated elsewhere in this document, this Security Target has been instantiated from two Protection
Profiles (TF-MRPP, AP-MRPP). Albeit, FIA_ATD.1 SFR is present in both the protection profiles, it has been
mapped to O.IDAUTH and O.SECFUN objectives in Table 6.3 of the AP-MRPP and to O.IDAUTH & O.SINUSE
objectives in Table 6.3 of the TF-MRPP. This ST has retained the mapping between the mentioned SFR and the
objectives as per Table 6.3 of the AP-MRPP. This is because the maintenance of security attributes (like the identity
and association of human user with authorized administrator role) by the TSF for individual users has no bearing on
the ability of the TOE to prevent reuse of authentication data (as per O.SINUSE). Hence in this ST the mapping of
FIA_ATD.1 is more appropriate with O.IDAUTH and O.SECFUN as opposed to O.IDAUTH & O.SINUSE.
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that since the TOE does not support remote access or administration, the only use of single-use
authentication mechanisms is for the Telnet and FTP proxies28
.
8.2.1.3 O.MEDIAT27
In order to implement O.MEDIAT, the TOE must mediate the flow of all information between
clients and servers located on internal and external networks governed by the TOE, disallowing
passage of non-conformant protocols and ensuring that residual information from a previous
information flow is not transmitted in any way. Both the authenticated and the unauthenticated
information flow control policies [FDP_IFC.1(1), FDP_IFC.1(2)] and functions [(FDP_IFF.1(1),
FDP_IFF.1(2)] combine to actively mediate the information flows to satisfy the objective.
Residual information protection (FDP_RIP.1) is used to ensure that residual information from a
previous flow is not transmitted. The components FMT_MSA.1(1), FMT_MSA.1(2),
FMT_MSA.1(3), FMT_MSA.1(4), Management of the security attributes and FMT_MSA.3,
Static attribute initialization, ensure the integrity of the information flow rules by allowing only
the authorized administrators to perform the above operations. . Together, the above SFRs help
satisfy the objective O.MEDIAT.
8.2.1.4 O.SECSTA
In order to implement O.SECSTA, upon initial start-up of the TOE or recovery from an
interruption in TOE service, the TOE must not compromise its resources or those of any
connected network. FMT_MOF.1(1) restricts the ability to startup the TOE to only authorized
administrators so that it cannot be compromised during this stage. Only the administrator, again,
is allowed to restore old values for TSF data (FMT_MOF.1(2)). Proper setting of restrictive
default security attributes (FMT_MSA.3) complements management of security attributes
(FMT_MSA.1(1), FMT_MSA.1(2), FMT_MSA.1(3), FMT_MSA.1(4)), and reference mediation
(FPT_RVM.1) to ensure that start-up or recover states in the TOE have a restrictive default state
that prevents compromise, as required by the objective. FAU_STG.1 protects the audit trails
from unauthorized deletion/modification and FAU_STG.429
prevents loss of audit data when the
audit trail is full by preventing auditable events.
28
O.SINUSE is included both in TF-MRPP and AP-MRPP. Albeit the TOE does not claim remote administration
(and hence single use authentication for the remote administrator) it however, does claim single use authentication
for proxy users. For the purpose of this ST, the O.SINUSE objective is aimed to mitigate the T.REPEAT and
T.REPLAY threats only while authenticating proxy (telnet, ftp) users and not remote administrators.
29
FAU_STG.4 requires the TSF to limit the number of audit records lost if the Audit Trail is Full. The TOE
by default is configured to automatically shut itself down in a normal manner when the disk that holds the
audit files reaches a threshold or maximum disk utilization capacity caused by an event of exhaustion or an
attack that effects audit data exhaustion. Hence, when this threshold capacity (depicted as a percentage of
the total disk space) is reached, the TOE initiates an audited shutdown of itself and in the process stops new
audit events long before the remaining disk space is filled. This prevents any audit data loss. Based on this
detailed analysis of the TOE it can be concluded that the TOE is expected to lose no data when the audit trail
gets full. In the event of any storage failure, the loss of audit data is also limited by the automatic capabilities
of the TOE to archive data on a scheduled basis. In this case, the worst-case lose of data is limited to the
amount of time since the last regularly scheduled archive, typically 24 hours or less.
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8.2.1.5 O.SELPRO
In order to implement O.SELPRO, the TOE must protect itself against attempts by unauthorized
users to bypass, deactivate, or tamper with TOE security functions. The component FPT_RVM.1
protects against bypass by requiring that all accesses be mediated. The component FPT_SEP.1
protects against attempts to tamper or deactivate security functions by providing a separate
domain of execution for the functions. Any brute force attempts made by an attacker are
countered by FIA_AFL.1, which bounds the number of invalid attempts and requires
intervention by an authorized administrator thereafter. The component FAU_STG.1 protects the
audit related TOE security functions and hence the stored audit trails from unauthorized
deletion/modification, and the component FAU_STG.429
ensures that no audit data is lost when
the audit trail is full.
8.2.1.6 O.AUDREC
In order to implement O.AUDREC, the TOE must provide a means to record a readable audit
trail of security-related events, with accurate dates and times, and a means to search and sort the
audit trail based on relevant attributes. The SFRs from the audit family are included to ensure
the TOE collects audit records (FAU_GEN.1 and FPT_STM.1), and allows them to be reviewed
(FAU_SAR.1) with searching and sorting capability (FAU_SAR.3).
8.2.1.7 O.ACCOUN
In order to implement O.ACCOUN, the TOE must provide user accountability for information
flows through the TOE and for authorized administrator use of security functions related to audit.
Accountability in the TOE is implemented by requiring that each user to be successfully
authenticated to the TOE before performing any operation on it (FIA_UID.2), and by requiring
collection of audit (FAU_GEN.1).
8.2.1.8 O.SECFUN
In order to implement O.SECFUN, the TOE must provide functionality that enables an
authorized administrator to use the TOE security functions, and must ensure that only authorized
administrators are able to access such functionality. The management components
FMT_MOF.1(1), FMT_MOF.1(2), FMT_MSA.1(1), FMT_MSA.1(2), FMT_MSA.1(3),
FMT_MSA.1(4), FMT_MSA.3, FMT_MTD.1(1), FMT_MTD.1(2) & FMT_MTD.2 and the
audit components FAU_STG.1 & FAU_STG.429
ensure that only authorized administrators are
allowed to manage their respective behavior. Similarly, user association with roles is provided by
FIA.ATD.1.
8.2.1.9 O.LIMEXT
In order to implement O.LIMEXT, the TOE must provide the means for an authorized
administrator to control and limit access to TOE security functions by an authorized external IT
entity. FMT_MOF.1(1) and FMT_MOF.1(2) ensure that only an authorized administrator can
communicate with the TOE and manage its security functions.
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8.2.2 Security Functional Requirements Rationale for the IT Environment
There are no SFRs for the IT Environment.
8.2.3 Security Assurance Requirements Rationale
The rationale for the Security Assurance Requirements is defined in Chapter 6 Section 6.3.
8.3 TOE Summary Specification Rationale
The rationale for the TOE Summary Specification is defined in Chapter 6, Section 6.2.
8.4 PP Claims Rationale
The rationale for the Protection Profile conformance claims is defined in Chapter 7, Section 7.4
Protection Profile Rationale.
8.5 Strength of Functions (SOF) Rationale
8.5.1 SOF for Password Mechanism
The rationale for the chosen level is based on the low attack potential of the threat agents
identified in the ST. This security target includes a probabilistic or permutational function. The
list of relevant security functions and security functional requirements includes:
o Identification and Authentication
o FIA_UAU.1 - Timing of authentication
o FIA_UAU.5 – Multiple Authentication Mechanisms
The password used at administrator login from a locally connected console is the only
probabilistic or permutational function on which the strength of the authentication
mechanism depends.
The TOE places the following restrictions on the passwords selected by the user:
o The password must be at least eight long;
Furthermore, the user is advised not to use consecutive sequences, or easily guessable passwords
The password space is calculated as follows:
Patterns of human usage are important considerations that can influence the approach to
searching apassword space, and thus affect SOF. Assuming the worst case scenario and the user
chooses a number comprising only eight characters, the number of password permutations is:
Each one of the 8 characters in the password is allowed any one of the following 95 ASCII
values:
32 sp 33 ! 34 " 35 # 36 $ 37 % 38 & 39 '
40 ( 41 ) 42 * 43 + 44 , 45 - 46 . 47 /
48 0 49 1 50 2 51 3 52 4 53 5 54 6 55 7
56 8 57 9 58 : 59 ; 60 < 61 = 62 > 63 ?
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64 @ 65 A 66 B 67 C 68 D 69 E 70 F 71 G
72 H 73 I 74 J 75 K 76 L 77 M 78 N 79 O
80 P 81 Q 82 R 83 S 84 T 85 U 86 V 87 W
88 X 89 Y 90 Z 91 [ 92 \ 93 ] 94 ^ 95 _
96 ` 97 a 98 b 99 c 100 d 101 e 102 f 103 g
104 h 105 i 106 j 107 k 108 l 109 m 110 n 111 o
112 p 113 q 114 r 115 s 116 t 117 u 118 v 119 w
120 x 121 y 122 z 123 { 124 | 125 } 126 ~
Thus, there are 95^8 = 6,634,204,312,890,625 potential password combinations implying that the
probability that the authentication data can be guessed is no greater than one in ninety five to the
power eight (95 ^ 8).
The amount of time it takes to manually type a password, given that authentcaion can only occur
based upon manual input, is 7 seconds.
An attacker can at best attempt (60/7= 8.6 password entries every minute, or 514 password
entries every hour. On average, an attacker would have to enter (6,634,204,312,890,625/ 2 =)
3,317,102,156,445,310 passwords, over (3,317,102,156,445,310 / 514) = 6,453,506,140,944
hours, before entering the correct password. The average successful attack would, as a result,
occur in slightly less than:
6,453,506,140,944 /24/365 = 736,701,614 years
In accordance with annex B.8 in the CEM, the elapse time of attack is not practical and thus
results in a high strength of function rating which exceeds SOF-Medium.
8.5.2 SOF for Single Use Authentication Mechanism
Strength of function rating of SOF-medium was designated for this TOE to exceed the U.S.
Government Application-Level Firewall Protection Profile for Medium Robustness
Environments upon which the TOE is modeled. The rationale for the chosen level is based on the
low attack potential of the threat agents identified in the ST.
The list of relevant security functions and security functional requirements includes:
o FIA_UAU.5 – Multiple Authentication Mechanisms
An analysis for the ‘Strength of Function’ for single-use authentication mechanism is provided
below:
1. For single use authentication the TOE includes the ‘RSA Authentication Manager version
6.0’ that validates the passcode corresponding to a user at any given time. This is done by
matching the actual passcode presented by the user at a given time to the computed
passcode calculated by the by the ‘Authentication Manager’ for the same user at the same
given time. If the two passcodes match the user is successfully authenticated else a failure
corresponding to the user is registered.
2. The14 character passcode that is used to authenticate a user at any given time comprises
of the following two contiguous parts:
o 8 character (Alpha Nummeric) PIN Code that changes only on demand.
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o 6 digit (numeric) random token that changes every minute. The RSA authentication
Manager uses the ‘AES hashing of 128 bit seed’30
algorithm to generate the random
tokens that change every minute.
3. Assuming a worst case scenario where the entropy assigned to the 8 character PIN
number is zero (because it changes only on demand), the passcode contains only the 6
digit token that is truly unique, independent and random. This implies that at any given
minute the effective bit strength of the Passcode would be equal to the effective bit
strength of the 6 digit token.
Passcode Bit Strength = 2 ^ 19.93 = 1,000,000 [ i.e., one in 1,000,000]
4. The TOE also deploys the following functionality:
o Blacklisting of users on the ‘CyberGuard Firewall/VPN 6.2.1’ after 3 consecutive
invalid identification and authentication attempts.
o Disabling of tokens on the ‘RSA Authentication Manager version 6.0’ after 3
consecutive invalid passcodes corresponding to a user are entered.
NOTE:
If a user is blacklisted and his token is disabled he is deemed to fail all subsequent
authentication attempts even if he were to enter the correct passcode. For the user to be
able to authenticate successfully again, an authorized system administrator must
physically re-activate his token and remove him from the user blacklist database. Hence
theses TOE features/environment measures prevent even an expert attacker's use
of equipment.
5. Based on assertions 3 & 4 above a user with malicious intent shall have only 3 chances in
3 minutes to guess the random passcode that changes every minute. Each time the
probability of a user guessing the passcode would be:
1 / 1,000,000 = .000001
In accordance with annex B.8 in the CEM, the ‘Access to the TOE’ is:
o For a very limited time period and for a very limited number of times.
o Easily and automatically detectable.
30
A separate document from RSA shall be provided as evidence that RSA uses the CCEVS accepted ‘AES hashing
of 128 bit seed’ algorithm while generating random tokens.
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83
It is hence
not
practical
for an
attacker to
try and
access the
TOE
illegally
without
being
detected.
This
therefore
results in a
high
strength of
function
rating
which
exceeds
SOF-
Medium.
Strength of function rating of SOF-medium was designated for this TOE to exceed the U.S.
Government ‘Traffic-Filter Firewall Protection Profile for Medium-Robustness Environments’
and ‘Application-Level Firewall Protection Profile for Medium Robustness Environments’ upon
which the TOE is modeled.