Security Target for Symantec Gateway Security (SGS) 5000 Series Version 3.0 (Firewall Engine Only) Reference: SGS3\ST March 2006 Issue: 1.0a Symantec Corporation 275 Second Avenue Waltham, MA 02451 USA . Page 2 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Copyright notice Copyright © 1998-2006 Symantec Corporation. All Rights Reserved. Any technical documentation that is made available by Symantec Corporation is the copyright work of Symantec Corporation and is owned by Symantec Corporation. No part of this publication may be copied without the express written permission of Symantec Corporation, 20330 Stevens Creek Blvd., Cupertino, CA 95014. Issue 1.0a Page 3 of 77 22 Mar 2006 Ref.: SGS3\ST DOCUMENT AUTHORISATION Document Title Security Target for Symantec Gateway Security (SGS) 5000 Series Version 3.0 (Firewall Engine Only) Issue Date Description 0.1 Oct 2005 Draft issued for TSM 0.2 Oct 2005 Correct details of 5640 0.3 Nov 2005 Address EOR1 0.4 Nov 2005 Correct conformance claim 0.5 Feb 2006 Address EOR 4 0.6 Feb 2006 Address EOR 6 1.0a Mar 2006 Draft final issue Page 4 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Contents 1 INTRODUCTION TO THE SECURITY TARGET....................................................................................... 9 1.1 SECURITY TARGET IDENTIFICATION ............................................................................................................ 9 1.2 SECURITY TARGET OVERVIEW .................................................................................................................... 9 1.3 CC CONFORMANCE CLAIM .......................................................................................................................... 9 2 TOE DESCRIPTION....................................................................................................................................... 10 2.1 OVERVIEW OF THE SYMANTEC GATEWAY SECURITY5000 SERIES VERSION 3.0 (FIREWALL ENGINE)....... 10 2.2 SCOPE AND BOUNDARIES OF THE EVALUATED CONFIGURATION............................................................... 13 2.2.1 Physical Scope...................................................................................................................................... 13 2.2.2 Hardware and Software for the Appliance........................................................................................... 13 2.2.3 Hardware and Software Requirements for the SGMI........................................................................... 14 2.2.4 Hardware and Software for the Authentication Server ........................................................................ 14 2.2.5 Outside of the Scope............................................................................................................................. 15 3 SECURITY ENVIRONMENT........................................................................................................................ 16 3.1 INTRODUCTION .......................................................................................................................................... 16 3.2 THREATS.................................................................................................................................................... 16 3.2.1 Threats countered by the TOE.............................................................................................................. 16 3.2.2 Threats countered by the Operating Environment ............................................................................... 19 3.3 ORGANIZATIONAL SECURITY POLICIES...................................................................................................... 19 3.4 ASSUMPTIONS............................................................................................................................................ 19 4 SECURITY OBJECTIVES ............................................................................................................................. 21 4.1 TOE SECURITY OBJECTIVES...................................................................................................................... 21 4.1.1 IT Security Objectives .......................................................................................................................... 21 4.2 ENVIRONMENT SECURITY OBJECTIVES...................................................................................................... 23 4.2.1 IT Security Objectives .......................................................................................................................... 23 4.2.2 Non-IT Security Objectives................................................................................................................... 23 5 IT SECURITY REQUIREMENTS................................................................................................................. 25 5.1 TOE SECURITY REQUIREMENTS ................................................................................................................ 25 5.1.1 TOE Security Functional Requirements............................................................................................... 25 5.2 SECURITY REQUIREMENTS FOR THE IT ENVIRONMENT .............................................................................. 37 5.3 TOE SECURITY ASSURANCE REQUIREMENTS............................................................................................ 40 5.4 STRENGTH OF FUNCTION CLAIM................................................................................................................ 42 6 TOE SUMMARY SPECIFICATION............................................................................................................. 43 6.1 TOE SECURITY FUNCTIONS....................................................................................................................... 43 6.1.1 Identification and Authentication Function [IA].................................................................................. 43 6.1.2 Management and Security Function [MT] ........................................................................................... 43 6.1.3 Audit Function [AU] ............................................................................................................................ 44 6.1.4 Protection of TOE security Functions [PT] ......................................................................................... 45 6.1.5 User Data Protection Function [DP]................................................................................................... 45 6.2 IDENTIFICATION AND STRENGTH OF FUNCTION CLAIM FOR IT SECURITY FUNCTIONS............................... 49 6.3 ASSURANCE MEASURES............................................................................................................................. 50 7 PROTECTION PROFILES CLAIMS............................................................................................................ 51 8 RATIONALE.................................................................................................................................................... 52 8.1 INTRODUCTION .......................................................................................................................................... 52 8.2 SECURITY OBJECTIVES FOR THE TOE RATIONALE..................................................................................... 52 Issue 1.0a Page 5 of 77 22 Mar 2006 Ref.: SGS3\ST 8.3 SECURITY REQUIREMENTS RATIONALE ..................................................................................................... 59 8.3.1 Security Requirements are appropriate................................................................................................ 59 8.3.2 Environmental Security Requirements are appropriate....................................................................... 63 8.3.3 Security Requirement dependencies are satisfied................................................................................. 66 8.3.4 IT security functions satisfy SFRs......................................................................................................... 68 8.3.5 IT security functions mutually supportive ............................................................................................ 71 8.3.6 Justification of Explicit Requirements.................................................................................................. 71 8.3.7 Strength of Function claims are appropriate ....................................................................................... 72 8.3.8 Justification of Assurance Requirements.............................................................................................. 72 8.3.9 Assurance measures satisfy assurance requirements........................................................................... 72 Page 6 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 REFERENCES [CC] Common Criteria for Information Technology Security Evaluation, Version 2.2, January 2004 (aligned with ISO 15408). Issue 1.0a Page 7 of 77 22 Mar 2006 Ref.: SGS3\ST GLOSSARY AND TERMS Authentication data Information used to verify the claimed identity of a user. Authorised User Users, who may, in accordance with the TSP, perform an operation. Authorised External IT entity Any IT product or system, outside the scope of the TOE that may administer the security parameters of the TOE. Such entities are not subject to any access control requirements once authenticated to the TOE and are therefore trusted to not compromise the security policy enforced by the TOE. CC Common Criteria External IT entity Any IT product or system, untrusted or trusted, outside of the TOE that interacts with the TOE. FSB Front Side Bus FTP File Transfer Protocol Human User Any person who interacts with the TOE IP Internet Protocol IT Information Technology LCD Liquid Crystal Display Linux Operating System The operating system used by the appliance. MAC Media Access Control NAT Network Address Translation PP Protection Profile RFC Request for Comments SEF Symantec Enterprise Firewall SGS Symantec Gateway Security SFP Security Function Policy Page 8 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 SOF Strength of Function SGMI Security Gateway Management Interface SGMI operating system The operating system on the workstation used by the SGMI to access the TOE. ST Security Target TCP Transmission Control Protocol TOE Target of Evaluation TSAP Transport Service Application Protocol TSC TSF Scope of Control TSF TOE Security Functions TSP TOE Security Policy TSS TOE Summary Specification User Any entity (human user or external IT entity) outside the TOE that interacts with the TOE. User data Data created by and for the user that does not affect the operation of the TSF. VPN Virtual Private Network Issue 1.0a Page 9 of 77 22 Mar 2006 Ref.: SGS3\ST 1 Introduction to the Security Target 1.1 Security Target Identification 1 Title: Security Target for Symantec Gateway Security (SGS) 5000 Series Version 3.0 (Firewall Engine Only), issue 1.0a. 2 Assurance Level: EAL4, augmented with ALC_FLR.1. 1.2 Security Target Overview 3 The Symantec Gateway Security is a unique security solution that combines technologies from the Symantec Enterprise Firewall, Symantec Enterprise VPN, intrusion detection, content filtering and anti-virus scanning into one appliance. The Symantec Gateway Security maximizes network security without compromising performance. 4 The Symantec Gateway Security (SGS) 5000 Series Version 3.0 (Firewall Engine Only) is a Internet Protocol application and packet-filtering firewall. The application proxy provides connection services to the global Internet on behalf of hosts within a secured network; thus ensuring there is no direct connection between Internet and private networked hosts. The packet filtering allows the acceptance/refusal of data based on the attributes of the data packets. This assists the prevention of unauthorised services being accessed by Internet hosts. 5 The chapters of this Security Target are structured in accordance with the families in the [CC] ASE class, with the various rationales required by the ASE families collated in section 8. 1.3 CC Conformance Claim 6 This TOE has been developed using the functional components as defined in the Common Criteria version 2.2 [CC] Part 2 plus an additional functional component to interface to an external authentication server, with the assurance level of EAL4, augmented with ALC_FLR.1 as identified in Part 3 of [CC]. 7 In CC terms the Security Target is Part 2 extended and Part 3 conformant. Page 10 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 2 TOE Description 2.1 Overview of the Symantec Gateway Security5000 Series Version 3.0 (Firewall Engine) 8 This section presents an overview of the Symantec Gateway Security (SGS) 5000 Series Version 3.0 and the firewall engine to assist potential users in determining whether it meets their needs. 9 The Symantec Gateway Security is an integrated gateway security appliance that incorporates five core security functions into a single solution. The solution combines firewall, anti-virus, intrusion detection, content filtering and VPN capabilities in a single appliance. 10 The Target of Evaluation (TOE) for this evaluation is the Symantec Gateway Security Version 3.0 (Firewall Engine Only) software running on a 5000 series appliance, the Security Gateway Management Interface (SGMI) and the Appliance Liquid Crystal Display (LCD) screen. 11 The Symantec Gateway Security 5000 Series Version 3.0 (Firewall Engine Only) is an application level firewall (also referred to as the Symantec Gateway Security 5000 Series Version 3.0 appliance when including environment hardware and Symantec Gateway Security v3.0 when only considering software). The TOE uses a set of application-specific security proxies to validate each attempt to pass data in or out of the network it secures. This is substantially different from stateful packet filter firewalls that do not filter data at the application level. 12 The packets enter the TCP/IP stack of the Symantec Gateway Security 5000 Series Version 3.0 appliance. Various scanning techniques are then applied and completed via the TCP/IP protocol stack. After all tests are completed, if there are no problems, the packets are allowed to flow out of the Symantec Gateway Security 5000 Series Version 3.0 appliance to the next network segment. Issue 1.0a Page 11 of 77 22 Mar 2006 Ref.: SGS3\ST Diagram 2-1: Packet Flow through the Symantec Gateway Security 5000 Series Version 3.0 13 The Target of Evaluation (TOE) consists of three physical components, the firewall engine itself, and the Security Gateway Management Interface (SGMI) and the Appliance LCD screen that are used to manage the firewall. 14 The SGMI is a Java-based, standalone user interface that includes policy, location, system-monitoring, settings and reports. The SGMI is accessed by directing a web browser to the SGS and logging on with an Administrator's user name and password. There is no separate software to install. S y m a n te c G a te w a y S e c u rity S c o p e o f T O E F ire w a ll E n g in e S G M I W o rksta tio n In s id e R o u te r R o u te r O u tsid e In te rn e t A u th e n tic a tio n S e rv e r S G M I Page 12 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 15 The Appliance LCD screen displays the Symantec Gateway Security version number. LCD displays the following options:  System startup self-tests;  Performance monitoring;  System Menu. 16 The LCD can be locked from the SGMI. 17 The TOE’s security proxies perform the following functions:  Examine the contents of packets  Allow or deny connection based on IP address, user, time, type of service, and the interface the connection came in on.  Control direction and type of operations for applications.  Log all session data. 18 In addition the firewall engine provides the following functions:  Syn flooding attack protection;  Denial of Service protection;  Port scanning detection. 19 The TOE can be configured not to disclose IP addresses and for users to be unable to identify listening services. 20 For the evaluation six network interface cards will be used with the TOE. It is possible to identify each network interface as either ‘internal’ or ‘external’. If an interface is identified as external then the network to which it attaches is classed as being outside of the firewall. If an interface is identified as an internal interface then the network to which it attaches is classed as being inside (or behind) the firewall. 21 The workstation used to run SGMI will be connected directly to the appliance, using a physically secure connection such as a crossover cable. SGMI network traffic must not pass through shared network devices such as routers. 22 All traffic between each network attached to the TOE must flow through the firewall engine of the Symantec Gateway Security 5000 Series Version 3.0 to maintain security. The protocols that are within the scope of the evaluation are: Issue 1.0a Page 13 of 77 22 Mar 2006 Ref.: SGS3\ST HTTPi UDP FTP Ping DNS TELNET SMTP NTP RTSP IP NNTP POP3 RealAudio TCP 23 The application proxies through the TOE that are within the scope of the evaluation are: HTTP FTP NNTP RealAudio DNS NTP TELNET SMTP POP3 2.2 Scope and Boundaries of the Evaluated Configuration 24 The TOE configuration consists of: • The firewall itself; • The Security Gateway Management Interface (SGMI), which is used for local administration by the administrator; • The Appliance Liquid Crystal Display (LCD), which is used for administration by the administrator; 2.2.1 Physical Scope 25 The physical scope of the TOE is identified in Table 2-1. Software Symantec Gateway Security 5000 Series Version 3.0 (Firewall Engine Only) with Security Gateway Management Interface Including SGS3.0-Bundle B-February 9th 2006. Table 2-1: TOE Component Identification 2.2.2 Hardware and Software for the Appliance 26 The required IT environment for the TOE is a 5000 Series appliance (e.g. 5420, 5440, 5460, 5620, 5640, 5660). Table 2-2 identifies the explicitly tested underlying hardware of the TOE, which forms part of the IT environment. i HTTP proxy supports WebDAV (Web Distributed Authoring and Versioning) Page 14 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Hardware Symantec Gateway Security 5000 Series Model 5640 Software N/A Operating System Red Hat Linux 7.2 with a Linux 2.4.26 kernel. Ethernet Network Interfaces 8 x Intel Pro10/100/1000 Base-T Ethernet network interfaces User Interface 2 line x 16 character LCD Processor 3.0 Ghz 800 P4 Disk 160 GB EIDE Memory 2 GB Table 2-2: Tested platform of the TOE 2.2.3 Hardware and Software Requirements for the SGMI 27 The SGMI is the administration interface accessible via a workstation required for local administration of the TOE. The SGMI is part of the software on the appliance, and is accessed by directing a workstation browser to the appliance. Table 2-3 identifies the explicitly tested IT environment for the SGMI. Software Internet Explorer 6.0 SP1 Java Plug-in Version 1.5 No TOE specific software has to be loaded onto the workstation in order for the workstation to run SGMI. Operating System Windows XP Service Pack 2 Table 2-3: IT Environment for the SGMI 28 If the Java Plug-in is not already installed in the browser, it can also be downloaded from the appliance. The SGMI Java WebStart application is automatically downloaded directly from the appliance when an administrator connects their browser to the appliance for the first time. No TOE specific software has to be loaded onto the workstation in order for the workstation to run SGMI, which runs in a Java runtime environment. 29 The hardware that is required for the SGMI will be located with the SGS and have a direct link. No other applications will be loaded onto the machine. 2.2.4 Hardware and Software for the Authentication Server 30 An authentication server is required for single-use authentication. A commercially available authentication server that is compatible with the Symantec Gateway Security Version 3.0 should be used. Issue 1.0a Page 15 of 77 22 Mar 2006 Ref.: SGS3\ST 2.2.5 Outside of the Scope 31 Software and hardware features outside the scope of the defined TOE Security Functions (TSF) and thus not evaluated are:  Virtual Private Networking (VPN) functionality;  Symantec Enterprise VPN Client;  Content filtering;  High availability/load balancing;  User Authentication by one-time passwordii ;  Setup Wizard;  Anti-spam;  H.323 Connections;  Remote Administration;  Forward Filtering;  Secure Shell (SSH);  Console Port Access;  Tomcat Web server;  Intrusion Detection and Prevention;  Anti-virus;  Live update support;  Event Manager;  Policy Configuration Manager. ii One time password authentication for Telnet/Ftp connections is provided by a SecureID or RADIUS server as part of the environment of the TOE. Page 16 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 3 Security Environment 3.1 Introduction 32 This section provides the statement of the TOE security environment, which identifies and explains all: 1. known and presumed threats countered by either the TOE or by the security environment; 2. organisational security policies the TOE must comply with; 3. assumptions about the secure usage of the TOE, including physical, personnel and connectivity aspects. 33 Within the evaluation references are made to two operating systems, the appliance operating system and the operating system used by the SGMI. In order to distinguish between the two operating systems, the appliance operating system is referred to as the "Linux operating system", while the operating system on the workstation used by the SGMI is referred to as the "SGMI operating system". 3.2 Threats 34 This section identifies the threats to the IT assets against which protection is required by the TOE or by the security environment. 3.2.1 Threats countered by the TOE 35 The IT assets requiring protection are the services provided by, and data accessible via, hosts on the internal network (or networks if there are multiple network interfaces on the TOE configured as being behind the firewall). 36 The general threats to be countered are: • attackers outside of the protection of the TOE who may gain unauthorised access to resources within the internal network; • users on the internal network who may inappropriately expose data or resources to the external network. 37 If the TOE is configured to provide separation between different internal networks then the following general threats will also need to be countered: • a user on one of the internal networks who may gain unauthorised access to resources on another of the internal networks; • a user on one of the internal networks who may expose data or resources to users on other internal networks. Issue 1.0a Page 17 of 77 22 Mar 2006 Ref.: SGS3\ST 38 The threats that must be countered by the TOE are listed below. T.NOAUTH An unauthorised 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. T.REPEAT An unauthorised person may repeatedly try to guess authentication data in order to use this information to launch attacks on the TOE. T.REPLAY An unauthorised person may use valid identification and authentication data obtained to access functions provided by the TOE. T.ASPOOF An unauthorised 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 unauthorised person may send impermissible information through the TOE that results in the exploitation of resources on the internal network. T.OLDINF Because of a flaw in the TOE functioning, an unauthorised 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. 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 unauthorised person may read, modify, or destroy security critical TOE configuration data. T.AUDFUL An unauthorised 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 attacker actions. T.LOWEXP The threat of malicious attacks aimed at discovering exploitable vulnerabilities is considered low. Page 18 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 39 The following table identifies the threats that are partially met by the TOE. Threats Partially met by the TOE Reasons T.NOAUTH Part of the security of TOE is performed by the SGMI operating system, and the authentication server. This threat is partially met by the SGMI operating system and the authentication server. T.SELPRO The Linux operating system protects certain TOE sensitive data, for example the audit data. This threat is partially met by the Linux Operating System. T.AUDFUL The Linux operating system provides part of the auditing for TOE. This threat is partially met by the Linux Operating System. T.AUDACC The Linux operating system provides part of the auditing for TOE. This threat is partially met by the Linux Operating System. T.REPEAT This threat is partially met by the SGMI operating system and the authentication server, as authentication is performed by the SGMI operating system and the authentication server T.REPLAY This threat is partially met by the SGMI operating system and the authentication server, as authentication is performed by the SGMI operating system and the authentication server. T.LOWEXP As part of the security of TOE is performed by the Linux Operating System, the SGMI operating system and the authentication server this threat is partially met by the Linux Operating System, the SGMI operating system and the authentication server. Table 3-1 Threats partially met by the TOE and IT Environment Issue 1.0a Page 19 of 77 22 Mar 2006 Ref.: SGS3\ST 3.2.2 Threats countered by the Operating Environment 40 The threats that must be countered by technical and/or non-technical measures in the IT environment, or must be accepted as potential security risks are listed below. TE.USAGE The TOE may be inadvertently configured, used and administered in an insecure manner by either authorised or unauthorised persons. 41 Table 3-1 identifies the threats that are partially met by the operating environment. 3.3 Organizational Security Policies 42 There are no organizational security policies or rules with which the TOE must comply. 3.4 Assumptions 43 The following assumptions are assumed to exist. A.PHYSEC The TOE, SGMI operating system and authentication server are physically protected to prevent unauthorised users. Only authorised administrators have physical access to the TOE, SGMI operating system and the authentication server. A.LOWEXP The threat of malicious attacks aimed at discovering exploitable vulnerabilities is considered low. A.GENPUR There are no general-purpose computing (e.g. the ability to execute arbitrary code or application) and storage repository capabilities on the TOE, SGMI operating system or authentication server. A.PUBLIC The TOE, SGMI operating system and authentication server do not host public data. A.NOEVIL Authorised administrators for the TOE, SGMI operating system and authentication server are non-hostile and follow all administrator guidance; however, they are capable of error. A.SINGEN Information can not 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 Page 20 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 connection is part of the TOE. A.NOREMO Human users who are not authorised administrators can not access the TOE, the SGMI operating system or the authentication server remotely from the internal or external networks. A.REMOS The SGMI operating system and the authentication server are delivered to the user’s site, installed and administered in a secure manner. A.COMMS The communication links between the TOE, the SGMI operating system and the authentication server are physically protected. Issue 1.0a Page 21 of 77 22 Mar 2006 Ref.: SGS3\ST 4 Security Objectives 4.1 TOE Security Objectives 4.1.1 IT Security Objectives 44 The principal IT security objective of the TOE is to reduce the vulnerabilities of an internal network exposed to an external network (or another internal network should there be multiple internal networks) by limiting the hosts and services available. Additionally, the TOE has the objective of providing the ability to monitor established connections and attempted connections between networks. 45 The IT security objectives are listed below. O.IDAUTH The TOE must uniquely authenticate all users, before granting a user access to certain specified services (FTP / Telnet), 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, and must ensure 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 unauthorised 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 authorised administrator use of security functions related to audit. O.SECFUN The TOE must provide functionality that enables an authorised administrator to use the TOE security functions and must ensure that only Page 22 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 authorised administrators are able to access such functionality. O.LIMEXT The TOE must provide the means for an authorised administrator to control and limit access to TOE security functions by an authorised external IT entity. O.EAL The TOE must be structurally tested and shown to be resistant to obvious vulnerabilities. 46 The following table identifies the IT Security objectives listed that are partially met by the IT environment. Partially met by IT Environment Reasons O.IDAUTH Part of the security of the TOE is provided by the authentication server using a Single-use authentication mechanism. O.SINUSE Part of the security of the TOE is provided by the SGMI Operating System and the authentication server using a Single-use authentication mechanism. O.SECSTA Part of the security of the TOE is provided by the Linux Operating System, the SGMI Operating System and the authentication server using a Single-use authentication mechanism. O.SELPRO Part of the security of the TOE is provided by the Linux Operating System and the SGMI Operating System. O.AUDREC Part of the security of the TOE is provided by the Linux Operating System. O.ACCOUN Part of the security of the TOE is provided by the Linux Operating System. O.SECFUN Part of the security of the TOE is provided by the Linux Operating System, the SGMI Operating System and the authentication server. O.LIMEXT Part of the security of the TOE is provided by the Linux Operating System, the SGMI Operating System and the authentication server O.EAL Part of the security of the TOE is provided by the Linux Operating System, the SGMI Operating System and the authentication server. Table 4-1 IT Security Objective partially met by IT Environment and TOE Issue 1.0a Page 23 of 77 22 Mar 2006 Ref.: SGS3\ST 4.2 Environment Security Objectives 4.2.1 IT Security Objectives 47 The following IT security objectives are met by the environment. OE.LOWEXP The threat of malicious attacks aimed at discovering exploitable vulnerabilities is considered low. OE.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, the SGMI operating system and the authentication server. OE.PUBLIC The TOE, the SGMI operating system and the authentication server do not host public data. OE.SINGEN Information can not flow among the internal and external networks unless it passes through the TOE. OE.NOREMO Human users who are not authorised administrators can not access the TOE, the SGMI operating system or the authentication server remotely from the internal or external networks. 48 Table 4-1 identifies the IT security objectives that are partially met by the IT environment. 4.2.2 Non-IT Security Objectives 49 The non-IT environment security objectives are to be satisfied without imposing technical requirements on the TOE. That is, they will not require the implementation of functions in the TOE hardware and/or software. Thus, they will be satisfied largely through application of procedural or administrative measures. OE.PHYSEC The TOE, the SGMI operating system and the authentication server must be physically protected so only authorised administrators have access. (The TOE must only be administered locally). OE.COMMS The communication links between the TOE, the SGMI operating system and the authentication server must be physically protected. OE.NOEVIL Authorised administrators of the TOE, the SGMI Page 24 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 operating system and the authentication server must be non-hostile and follow all administrator guidance; however, they may be capable of error. OE.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. OE.GUIDAN The TOE must be delivered to the user's site, installed, administered, and operated in a manner that maintains security OE.ADMTRA Authorised administrators must be trained as to establishment and maintenance of security policies and practices. OE.REMOS The SGMI operating system and the authentication server must be delivered to the user's site, installed and administered in a secure manner. Issue 1.0a Page 25 of 77 22 Mar 2006 Ref.: SGS3\ST 5 IT Security Requirements 5.1 TOE Security Requirements 5.1.1 TOE Security Functional Requirements 50 The TOE security functional requirements consist of components from Part 2 of the CC and one explicitly stated requirement (FIA_UAU_SERV.1). They are listed in the following table, along with an indication of the requirements that are either fully or partially met by the TOE. Functional Components Partially / Fully met by the TOE FIA_UAU_SERV.1 Single-use authentication server Fully FDP_IFC.1 Subset Information Flow Control (1) Fully FDP_IFC.1 Subset Information Flow Control (2) Fully FDP_IFF.1 Simple Security Attributes (1) Fully FDP_IFF.1 Simple Security Attributes (2) Fully FMT_MSA.1 Management of security attributes (1) Fully FMT_MSA.1 Management of security attributes (2) Fully FMT_MSA.1 Management of security attributes (3) Fully FMT_MSA.1 Management of security attributes (4) Fully FMT_MSA.3 Static Attribute Initialisation Fully FMT_SMF.1 Specification of Management Functions (1) Fully FPT_RVM.1 Non-Bypassability of the TSP Fully FPT_SEP.1 TSF domain separation Partially FAU_GEN.1 Audit Data Generation Partially Page 26 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Functional Components Partially / Fully met by the TOE FAU_SAR.1 Audit review Fully FAU_SAR.3 Selectable audit review Fully FAU_STG.4 Prevention of audit data loss Fully FMT_MOF.1 Management of Security Functions Behaviour (1) Fully FMT_MOF.1 Management of Security Functions Behaviour (2) Fully Table 5-1: Functional Requirements Identification and Authentication 51 This section addresses the requirements for functions to establish and verify a claimed user identity. This includes identification of any actions that the TOE may complete on the user’s behalf prior to identification or authentication. 52 Only an authorised administrator is able to interact directly with the SGS 5000 series Version 3.0 (Firewall Engine Only) through the SGMI / LCD. The authorised administrator is the only user who can log onto the Firewall Engine via the SGMI / LCD and access TSF data. The SGS 5000 series Version 3.0 (Firewall Engine Only) provides a basic form of access control mechanisms for identification and authentication. 53 Unauthenticated users use services provided by the TOE but do not visibly interact with the TOE. In order to control service requests from unauthenticated users, basic identification of the request through source address of request identification is performed. 54 FIA_UAU_SERV.1 Single-use authentication serveriii FIA_UAU_SERV.1.1 The TSF shall invoke an authentication server to authenticate any user's claimed identity according to the [following single authentication mechanism rule: a. single-use authentication mechanism shall be used for human users sending or receiving information through iii FIA_UAU_SERV.1 is an explicitly stated requirement. Issue 1.0a Page 27 of 77 22 Mar 2006 Ref.: SGS3\ST 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]. User Data Protection 55 This section specifies requirements for the TOE security functions and TOE security function policies relating to protecting user data. 56 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. 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. 57 FDP_IFC.1 Subset information flow control (1) 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; c) operation: pass information]. Page 28 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 58 FDP_IFC.1 Subset information flow control (2) 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 via the mechanisms invoked by FIA_UAU_SERV.1; b) information: FTP and Telnet traffic sent through the TOE from one subject to another; c) operation: initiate service and pass information]. 59 FDP_IFF.1 Simple security attributes (1)iv 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; • Port 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; •Time; •Address Transformation; •Service redirection; •Viability of application data; •URL blocking]. iv The complete set of functional elements of a component must be selected for inclusion in a ST. However, since the following functional elements from the FDP_IFF.1 (1) component do not add anything significant to the ST, they have been moved here to allow for a clearer, smoother flowing presentation of FDP_IFF.1(1). FDP_IFF.1.3 - The TSF shall enforce the [none]. FDP_IFF.1.4 - The TSF shall provide the following [none]. FDP_IFF.1.5 - The TSF shall explicitly authorize an information flow based on the following rules: [none]. Issue 1.0a Page 29 of 77 22 Mar 2006 Ref.: SGS3\ST 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 authorised 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 authorised 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.1.6 The TSF shall explicitly deny an information flow based on 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; Page 30 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 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 supported by the TOE (e.g. DNS, HTTP, SMTP), 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.] 60 FDP_IFF.1 Simple security attributes (2)v 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: • presumed address; • Port v The complete set of functional elements of a component must be selected for inclusion in a ST. However, since the following functional elements from the FDP_IFF.1 (2) component do not add anything significant to the ST, they have been moved here to allow for a clearer, smoother flowing presentation of FDP_IFF.1 (2). FDP_IFF.1.3 - The TSF shall enforce the [none]. FDP_IFF.1.4 - The TSF shall provide the following [none]. FDP_IFF.1.5 - The TSF shall explicitly authorize an information flow based on the following rules: [none]. Issue 1.0a Page 31 of 77 22 Mar 2006 Ref.: SGS3\ST 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; • Time; • Address Transformation; • Service redirection; • Viability of application data; • Extended authentication methods; • URL blocking]. 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 to the mechanisms invoked by FIA_UAU_SERV.1; • 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 authorised 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: • the human user initiating the information flow authenticates according to the mechanisms invoked by FIA_UAU_SERV.1; • all the information security attribute values are unambiguously permitted by the information flow security policy rules, where such rules may be Page 32 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 composed from all possible combinations of the values of the information flow security attributes, created by the authorised 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.1.6 The TSF shall explicitly deny an information flow based on 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 accompanied through protocol filtering proxies designed for that purpose.] Security Management Issue 1.0a Page 33 of 77 22 Mar 2006 Ref.: SGS3\ST 61 This section defines requirements for the management of security attributes that are used to enforce the TSF. 62 FMT_MOF.1 Management of security functions behavior (1) FMT_MOF.1.1 The TSF shall restrict the ability to enable, disable, the functions: a) [ operation of the TOE; b) single use authentication functions described in FIA_UAU_SERV.1] to [an authorised administrator] . 63 FMT_MOF.1 Management of security functions behavior (2) FMT_MOF.1.1 The TSF shall restrict the ability to enable, disable, determine and modify the behaviour 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 authorised external IT entities with the TOE] to [an authorised administrator]. 64 FMT_MSA.1 Management of Security Attributes (1) FMT_MSA.1.1 The TSF shall enforce the [UNAUTHENTICATED 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_IFF1.1(1)] to [the authorised administrator]. 65 FMT_MSA.1 Management of Security Attributes (2) FMT_MSA.1.1 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_IFF1.1(2)] to [the authorised administrator]. 66 FMT_MSA.1 Management of Security Attributes (3) Page 34 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 FMT_MSA.1.1 The TSF shall enforce the [UNAUTHENTICATED SFP ] to restrict the ability to delete and [create] the security attributes [ information flow rules described in FDP_IFF1.1(1)] to [the authorised administrator]. 67 FMT_MSA.1 Management of Security Attributes (4) FMT_MSA.1.1 The TSF shall enforce the [AUTHENTICATED SFP ] to restrict the ability to delete and [create] the security attributes [ information flow rules described in FDP_IFF1.1(2)] to [the authorised administrator]. 68 FMT_MSA.3 Static attribute initialization 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 [an authorised administrator] to specify alternative initial values to override the default values when an object or information is created. 69 FMT_SMF.1 Specification of Management Functions (1) FMT_SMF.1.1 The TSF shall be capable of performing the following security management functions: [those for which FMT_MSA.1 (1),(2),(3),&(4) and FMT_MOF.1 (1) & (2) restrict use to the authorised administrator]. Issue 1.0a Page 35 of 77 22 Mar 2006 Ref.: SGS3\ST Protection of the TOE Security Functions 70 This section specifies functional requirements that relate to the integrity and management of the mechanisms providing the TSF and TSF data. 71 FPT_RVM.1 Non-bypassability of the TSP 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. 72 FPT_SEP.1 TSF domain separation 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 Security Audit 73 This section involves recognising, recording and storing information related to security relevant activities. 74 FAU_GEN.1 Audit data generation 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 5.2]. 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 ST, [information specified in column three of Table 5.2]. Page 36 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Functional Component Auditable Event Additional Audit Record Contents FDP_IFF.1 All decisions on requests for information flow. The presumed addresses of the source and destination subject. FMT_MOF.1 Use of the functions listed in this requirement pertaining to audit. The identity of the authorised administrator performing the operation FMT_SMF.1 Use of the management functions. The identity of the authorised administrator performing the operation FIA_UAU_SERV.1 Any use of the authentication mechanism. The user identities provided to the TOE Table 5-2: Auditable Event 75 FAU_SAR.1 Audit review FAU_SAR.1.1 The TSF shall provide [an authorised 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. 76 FAU_SAR.3 Selectable audit review FAU_SAR.3.1 The TSF shall provide the ability to perform searches of audit data based on: a) [user identity; b) presumed subject address; c) ranges of dates; d) ranges of times; e) ranges of addresses]. 77 FAU_STG.4 Prevention of audit data loss FAU_STG.4.1 The TSF shall prevent auditable events, except those taken by the authorised administrator and [shall limit the number of audit records lost] if the audit trail is full. Issue 1.0a Page 37 of 77 22 Mar 2006 Ref.: SGS3\ST 5.2 Security requirements for the IT Environment 78 This section details the IT security requirements that are met by the IT environment of the TOE. Table 5-3 lists the IT security requirements to be provided by the IT environment: Functional Components Partially / Fully met by the IT environment FIA_UAU.2 User authentication before any action Fully FIA_UAU.4 Single-use authentication mechanisms Fully FIA_UID.2 User identification before any action Fully FPT_SEP.1 TSF domain separation Partially FPT_STM.1 Reliable Time Stamps Fully FAU_GEN.1 Audit Data Generation Partially FAU_STG.1 Protected audit trail storage Fully FMT_MOF.1 Management of security functions behavior (3) Fully FMT_SMF.1 Specification of Management Functions (2) Fully Table 5-3: IT Security Requirements of the Environment 79 FIA_UAU.2 User authentication before any actionvi FIA_UAU.2.1 The TSF shall require each user to be successfully authenticated before allowing any other TSF-mediated actions on behalf of that user. vi FIA_UAU.2 and FIA_UID.2 are fully met by the SGMI operating system. Page 38 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 80 FIA_UAU.4 Single-use authentication mechanismsvii FIA_UAU.4.1 The TSF shall prevent reuse of authentication data related to [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]. 81 FIA_UID.2 User identification before any actionviii 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. 82 FPT_SEP.1 TSF domain separationix 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 83 FPT_STM.1 Reliable time stampsx FPT_STM.1.1 The TSF shall be able to provide reliable time stamps for its own use. vii FIA_UAU.4 is fully met by the authentication server using a Single-use authentication mechanism. viii FIA_UAU.2 and FIA_UID.2 are fully met by the SGMI operating system. ix FPT_SEP.1 is partially met by the Linux operating system. x FPT_STM.1 is fully met by the Linux operating system. Issue 1.0a Page 39 of 77 22 Mar 2006 Ref.: SGS3\ST 84 FAU_GEN.1 Audit data generationxixii 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 5.4]. 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 ST, [information specified in column three of Table 5.4]. Functional Component Auditable Event Additional Audit Record Contents FPT_STM.1 Changes to the time. The identity of the authorised administrator performing the operation. Table 5-4: Auditable Event 85 FAU_STG.1 Protected audit trail storagexiii FAU_STG.1.1 The TSF shall protect the stored audit records from unauthorised deletion. FAU_STG.1.2 The TSF shall be able to prevent unauthorised modifications to the audit records in the audit trail. xi FAU_GEN.1 is partially met by the Linux operating system. xii The management of the audit trail is performed by the following TOE SFRs: FMT_MOF.1(2), FMT_SMF.1(1), FAU_SAR.1, FAU_SAR.3 and FAU_STG.4. xiii FAU_STG.1 is fully met by the Linux operating system. Page 40 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 86 FMT_MOF.1 Management of security functions behavior (3)xiv FMT_MOF.1.1 The TSF shall restrict the ability to enable, disable the functions: a) [single use authentication functions described in FIA_UAU.4 on the authentication server] to [an authorised administrator]. 87 FMT_SMF.1 Specification of Management Functions (2)xv FMT_SMF.1.1 The TSF shall be capable of performing the following security management functions: [those for which FMT_MOF.1 (3) restrict use to the authorised administrator]. 5.3 TOE Security Assurance Requirements 88 The assurance requirements for this Security Target, taken from Part 3 of the CC, comprise the EAL4 level of assurance augmented with ALC_FLR.1. The assurance components are summarized in the following table. Assurance Class Assurance Components ACM_AUT.1 Partial CM automation Configuration management ACM_CAP.4 Generation support and acceptance procedures ACM_SCP.2 Problem tracking CM coverage Delivery and operation ADO_DEL.2 Detection of modification xiv FMT_MOF.1(3) is fully met by the authentication server only allowing modification by authorized administrators. xv FMT_SMF.1(2) is fully met by the authentication server using a Single-use authentication mechanism. Issue 1.0a Page 41 of 77 22 Mar 2006 Ref.: SGS3\ST Assurance Class Assurance Components ADO_IGS.1 Installation, generation and start-up procedures ADV_FSP.2 Fully defined external interfaces ADV_HLD.2 Security enforcing high-level design Development ADV_IMP.1 Subset of the implementation of the TSF ADV_LLD.1 Descriptive low-level design ADV_RCR.1 Informal correspondence demonstration ADV_SPM.1 Informal TOE security policy model Guidance documents AGD_ADM.1 Administrator guidance AGD_USR.1 User guidance ALC_DVS.1 Identification of security measures ALC_FLR.1 Basic Flaw Remediation Life cycle support ALC_LCD.1 Developer defined life-cycle model ALC_TAT.1 Well-defined development tools ATE_COV.2 Analysis of coverage Page 42 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Assurance Class Assurance Components ATE_DPT.1 Testing: high-level design Tests ATE_FUN.1 Functional testing ATE_IND.2 Independent testing – sample AVA_MSU.2 Validation of analysis Vulnerability assessment AVA_SOF.1 Strength of TOE security function evaluation AVA_VLA.2 Independent vulnerability analysis Table 5-5: Assurance Requirements: EAL4 augmented with ALC_FLR.1 89 Further information on these assurance components can be found in [CC] Part 3. 5.4 Strength of Function Claim 90 A Strength of Function (SOF) claim of SOF-Medium is made for the TOE. No TOE Security functions contain a probabilistic or permutational mechanism. 91 For a justification of the Strength of Function claim see Section 8.3.7. Issue 1.0a Page 43 of 77 22 Mar 2006 Ref.: SGS3\ST 6 TOE Summary Specification 6.1 TOE Security Functions 92 This section describes the security functions provided by the TOE to meet the security functional requirements specified for the TOE in Section 5.1. 6.1.1 Identification and Authentication Function [IA] 93 Upon receipt of a request to send or receive Telnet / FTP through the TOE, a request for authentication must be issued to an external authentication server. The response from the external authentication server must be received prior to any further processing of the request. [IA1] 6.1.2 Management and Security Function [MT] 94 The authorised administrator can delete, modify, and add to a rule in the unauthenticated SFP. [MT1] 95 The authorised administrator can delete, modify, and add to a rule in the authenticated SFP. [MT2] 96 The authorised administrator can delete and create information flow rules in the unauthenticated SFP, as described by SFR FDP_IFF.1 (1). [MT3] 97 The authorised administrator can delete and create information flow rules in the authenticated SFP, as described by SFR FDP_IFF.1 (2). [MT4] 98 The TSF shall provide restrictive default values for the information flow security attributes for Unauthenticated and authenticated SFPs. [MT5] 99 The authorised administrator has the ability to enable and disable the following functions: [MT6] a) Operation of the TOE. The operation refers to the ability to control all information flows; b) Single use authentication’s functions. 100 The authorised administrator has the ability to enable, disable, determine and modify the behavior of the following functions: [MT7] a) Audit management; b) Backup and restore for TSF data, information flow rules, and audit trail data; and c) Communication of authorised external IT entities with the TOE. Page 44 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 101 The authorised administrator shall be able to specify initial values to override the default values for security attributes when an object or information is created. [MT8] 6.1.3 Audit Function [AU] 102 The accounting mechanisms cannot be disabled. The start-up and shutdown of audit functions is synonymous with the start-up and shutdown of the TOE. Start- up and shut-down of the TOE specific components can be configured to be recorded in the audit trail. [AU1] 103 It is possible to generate audit records for the following auditable events: [AU2] • Start-up and shutdown of the audit functions; • All level of challenge response (single use authentication); • User identities for single use authentication and audit trail management; • Every successful inbound and outbound connection; • Every unsuccessful inbound and outbound connection; • Creating, deleting, and modifying of rules and associated attributes; • Creating, deleting, and emptying of the audit trail. 104 For each event the Audit Function will record the following: [AU3] • Date and time of the event; • User identity (for single use authentication and audit trail management ); • System name; • Component name; • Process id; • Type of event or service; • Success or failure of the event; • Message number; • Message description which includes: • Source and destination IP address (for connections only); • Prototype Port number. 105 The authorised administrator has read access only to all audit trail data through the controlled interface SGMI logfile window. [AU4] 106 The authorised administrator, via the SGMI, is able to perform searches of audit data based on: [AU5] • Date and time ranges; • Event Type • System name; • Component name; • Process identification number; • Message number; • Pattern matching via regular expression implementation. The user identification, source address and a range of addresses can be searched using Issue 1.0a Page 45 of 77 22 Mar 2006 Ref.: SGS3\ST this facility as required by the SFR FAU_SAR.3. 107 Archiving is a manual process that is performed on the log files. The files are retained as long as there is space available. The authorised administrator is informed when the space limit is nearly reached. Once the audit trail becomes full, the TSF drops all connections through the TOE. [AU6] 6.1.4 Protection of TOE security Functions [PT] 108 The TOE provides self-protection from external modification or interference of the TSF code or data structures by untrusted subjects via the vulture daemon. Untrusted subjects cannot bypass checks, which always must be invoked. [PT1] 109 The functions that enforce the TOE Security Policy (TSP) are always invoked and completed, before any function within the TSF Scope of Control (those interactions within the TOE that are subject to the rules of the TSP) is allowed to proceed. [PT2] 110 The TSF protects itself, by denying all processes unless a process is specifically stated by the TSF. [PT3] 6.1.5 User Data Protection Function [DP] 111 The Time range template function of the TOE provides the facility of allowing an administrator to specify the time that a specific user may have access. This function can only be accessed from the Rules icon within the Security Gateway Management Interface (SGMI). [DP1] 112 The TOE provides a flow control mechanism in the form of security policy rules for all connections through the TOE for either inbound traffic (external to internal) or outbound traffic (internal to external). [DP2] 113 The TSF permits or denies authenticated connections depending on the security policy rules created by the administrator. [DP3] 114 The TSF evaluates packets on a “best fit” method, to ensure that the most constructive and specific security policy rule for each connection attempt is applied. [DP4] 115 The security policy rules are non-order dependent. [DP5] 116 All Connections are denied unless a specific rule has been set-up to allow information to flow. [DP6] 117 The Service used can be one of the following protocols: [DP7] HTTP UDP FTP Ping DNS TELNET SMTP NTP RTSP IP Page 46 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 NNTP POP3 RealAudio TCP 118 The application proxies through the TOE that are within the scope of the evaluation are: [DP8] HTTP RealAudio NNTP NTP DNS POP3 TELNET SMTP FTP 119 There are two main types of information flow that the TOE enforces: [DP9] a) Unauthenticated – An external IT entity on an internal or external network sending information through the TOE to other external IT entities. b) Authenticated – users on an internal or external network who must be authenticated at the TOE before using any protocol services. Unauthenticated 120 The TSF shall enforce unauthenticated information flow based on the following attributes: [DP10] a) Subject security attributes: • Presumed address, • Port. 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; • Time; • Address Transformation; • Service redirection; • Viability of application data; • URL blocking. 121 Unauthenticated information flow shall be permitted: [DP11] • For unauthenticated external IT entities that send and receive information through the TOE to one another; • For traffic sent through the TOE from one subject to another; • To Pass information. 122 Rules in the Security policy are defined by the TOE authorised Administrator, and allow the parameters stated in paragraph 119 to be set for unauthenticated traffic flow. [DP12] Issue 1.0a Page 47 of 77 22 Mar 2006 Ref.: SGS3\ST 123 Traffic flows from the configured internal network to another connected network shall only be permitted if all the information security attribute values created by the authorised administrator are permitted. [DP13] 124 Traffic flows from the configured internal network to another connected network shall only be permitted if the presumed address of the source subject translates to an internal network address. [DP14] 125 Traffic flows from the configured internal network to another connected network shall only be permitted if the presumed address of the destination subject translates to an address on another connected network. [DP15] 126 Traffic flows from the external network to another connected network shall only be permitted if all the information security attribute values created by the administrator are permitted. [DP16] 127 Traffic flows from the external network to another connected network shall only be permitted if the presumed address of the source subject translates to an external network address. [DP17] 128 Traffic flows from the external network to another connected network shall only be permitted if the presumed address of the destination subject translates to an address on another connected network. [DP18] 129 Access or services requests shall be denied from an external TOE interface if the presumed address of the source for the traffic flow is an external IT entity on an internal network. [DP19] 130 Access or services requests shall be denied from an internal TOE interface if the presumed address of the source for the traffic flow is an external IT entity on an external network. [DP20] 131 Access or services requests shall be denied from an internal or external TOE interface with the presumed address of the source for the traffic flow is an external IT entity on a broadcast network. [DP21] 132 Access or services requests shall be denied from an internal or external TOE interface with the presumed address of the source for the traffic flow is an external IT entity on a loopback network. [DP22] 133 Traffic flows in which the subject specifies the route the information flow shall flow to its destination shall be denied. [DP23] 134 Protocol filtering proxies shall deny access or request services to protocols that do not conform to the associated published protocol specification. [DP24] Page 48 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Authenticated 135 The TSF shall enforce authenticated information flow based on the following attributes: [DP25] a) Subject security attributes: • Presumed address; • Port. 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; • Time; • Address Transformation; • Service redirection; • Viability of application data; • Extended authentication methods; • URL blocking. 136 Authenticated information flow shall be permitted for human users and external IT entities that send or receive FTP and Telnet information through the Firewall, only after the human user initiating the information flow has been successfully authenticated using an authentication server. [DP26] 137 Rules in the Security policy are defined by the TOE authorised Administrator, and allow the parameters stated in paragraph 134 to be set for each authenticated traffic flow. [DP27] 138 Traffic flows from the configured internal network to the another connected network shall only be permitted if the human user initiating the traffic flow authenticates using authentication server for FTP and Telnet. [DP28] 139 Traffic flows from an internal network to another connected network shall only be permitted if all the information security attribute values created by the authorised administrator are permitted. [DP29] 140 Traffic flows from a controlled subject and another controlled subject via a controlled operation shall only be permitted if the presumed address of the source subject in the traffic flow, translates to an address on the internal network. [DP30] 141 Traffic flows from an internal network to another connected network shall only be permitted if the presumed address of the destination subject translates to an address on the other connected network. [DP31] Issue 1.0a Page 49 of 77 22 Mar 2006 Ref.: SGS3\ST 142 Traffic flows from an external network to the another connected network shall only be permitted if the human user initiating the traffic flow authenticates using an authentication server for FTP and Telnet. [DP32] 143 Traffic flows from an external network to another connected network shall only be permitted if all the information security attribute values created by the administrator are permitted. [DP33] 144 Traffic flows from the external network to another connected network shall only be permitted if the source address of the packet translate to an address on the external network. [DP34] 145 Traffic flows from the external network to another connected network shall only be permitted if the destination address of the packet translate to an address on the other connected network. [DP35] 146 Access or services requests shall be denied from an external TOE interface if the presumed address of the source for the traffic flow is an external IT entity on an internal network. [DP36] 147 Access or services requests shall be denied from an internal TOE interface if the presumed address of the source for the traffic flow is an external IT entity on an external network. [DP37] 148 Access or services requests shall be denied from an internal or external TOE interface if the presumed address of the source for the traffic flow is an external IT entity on a broadcast network. [DP38] 149 Access or services requests shall be denied from an internal or external TOE interface if the presumed address of the source for the traffic flow is an external IT entity on a loopback network. [DP39] 150 Traffic flows in which the subject specifies the route the information flow shall flow to its destination shall be denied. [DP40] 151 Protocol filtering proxies shall deny access or services to the following protocols that do not conform to the associated published protocol specification: FTP and Telnet. [DP41] 6.2 Identification and Strength of Function Claim for IT security Functions 152 This Security Target claims that the general strength of the security functions provided by the TOE is SOF-Medium. 153 No specific strength of function metric is defined. Page 50 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 6.3 Assurance Measures 154 Assurance measures will be produced to comply with the Common Criteria Assurance Requirements for EAL4 augmented with ALC_FLR.1. Table 8-6 maps the deliverables to the assurance requirements. Issue 1.0a Page 51 of 77 22 Mar 2006 Ref.: SGS3\ST 7 Protection Profiles Claims No claims against a protection profile are made. Page 52 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 8 Rationale 8.1 Introduction 155 This section demonstrates that the TOE provides an effective set of IT security countermeasures within the security environment and that the TOE summary specification addresses the requirements. 8.2 Security Objectives for the TOE Rationale 156 Table 8-1 demonstrates how the IT security objectives and environment objectives of the TOE counter the IT threats and environment threats identified in Section 3.2.1 and 3.2.2. Issue 1.0a Page 53 of 77 22 Mar 2006 Ref.: SGS3\ST Threats/ Assumptions Objectives T.NOAUTH T.REPEAT T.REPLAY T.ASPOOF T.MEDIATE T.OLDINF T.AUDACC T.SELPRO T.AUDFUL T.LOWEXP TE.USAGE A.PHYSEC A.LOWEXP A.GENPUR A.PUBLIC A.NOEVIL A.SINGEN A.DIRECT A.NOREMO A.REMOS A.COMMS O.IDAUTH     O.SINUSE         O.MEDIAT             O.SECSTA         O.SELPRO             O.AUDREC     O.ACCOUN     O.SECFUN             O.LIMEXT     O.EAL     OE.PHYSEC     OE.LOWEXP     OE.GENPUR     OE.PUBLIC     OE.NOEVIL     OE.SINGEN     OE.DIRECT     OE.NOREMO     OE.GUIDAN         OE.ADMTRA         OE.REMOS     OE.COMMS     Table 8-1 Mapping of Objectives to Threats and Assumptions Issue 1.0a Page 54 of 77 22 Mar 2006 Ref.: SGS3\ST 157 The following are justifications for Objectives that are met by the TOE. 158 O.MEDIAT 159 This security objective is necessary to counter the threats: T.ASPOOF, T.MEDIAT and T.OLDINF which have to do with getting impermissible information to flow through the TOE. This security objective requires that all information that passes through the networks is mediated by the TOE and that no residual information is transmitted. 160 The following are justifications for Objectives that are partially met by the TOE and partially by the IT Environment 161 O.IDAUTH 162 This security objective is necessary to counter the threat: T.NOAUTH because it requires that users be uniquely identified before accessing the TOE. 163 The authentication server authenticates users using a single-use authentication mechanism. 164 O.SINUSE 165 This security objective is necessary to counter the threats: T.REPEAT and T.REPLAY because it requires that the TOE prevent the reuse of authentication data so that even if valid authentication data is obtained, it will not be used to mount an attack. 166 The authentication server authenticates users using a single-use authentication mechanism. 167 O.SECSTA 168 This security objective is necessary to counter the threats: T.NOAUTH and T.SELPRO because it requires that no information is compromised by the TOE upon start-up or recovery. 169 The Linux operating system performs part of the resistance to penetration attacks. 170 O.SELPRO 171 This security objective is necessary to counter the threats: T.SELPRO, T.AUDFUL and T.NOAUTH because it requires that the TOE protect itself from attempts to bypass, deactivate, or tamper with TOE security functions. 172 The Linux operating system provides part of the protection for the TOE. Issue 1.0a Page 55 of 77 22 Mar 2006 Ref.: SGS3\ST 173 O.AUDREC 174 This security objective is necessary to counter the threat: T.AUDACC by requiring a readable audit trail and a means to search and sort the information contained in the audit trail. 175 The audit trail is stored on the Linux operating system. 176 O.ACCOUN 177 This security objective is necessary to counter the threat: T.AUDACC because it requires that users are accountable for information flows through the TOE and that authorised administrators are accountable for the use of security functions related to audit. 178 The Linux operating system performs part of the audit functions. 179 O.SECFUN 180 This security objective is necessary to counter the threats: T.NOAUTH, T.REPLAY and T.AUDFUL by requiring that the TOE provide functionality that ensures that only the authorised administrator has access to the TOE security functions. 181 The configuration of the SGMI operating system, Linux operating system and the authentication server support this objective. 182 O.LIMEXT 183 This security objective is necessary to counter the threat: T.NOAUTH because it requires that the TOE provide the means for an authorised administrator to control and limit access to TOE security functions. 184 The configuration of the SGMI operating system, Linux operating system and the authentication server support this objective. 185 O.EAL 186 This security objective is necessary to counter the threat: T.LOWEXP because it requires that the TOE is resistant to penetration attacks performed by an attacker possessing minimal attack potential. 187 The Linux operating system, the SGMI operating system and the authentication server perform part of the resistance to penetration attacks. Page 56 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 188 The following are justifications for Objectives that are met by the IT Environment. 189 OE.PHYSEC 190 This environmental security objective is necessary to support the assumption: A.PHYSEC because it requires that the TOE, the SGMI operating system and the authentication server are physically protected. 191 OE.LOWEXP 192 This environmental security objective is necessary to support the assumption: A.LOWEXP because it requires that the threat of malicious attacks aimed at discovering exploitable vulnerabilities is considered low. 193 OE.GENPUR 194 This environmental security objective is necessary to support the assumption: A.GENPUR because it requires that the TOE, the SGMI operating system and the authentication server do not provide general-purpose computing capabilities (e.g., the ability to execute arbitrary code or applications) or storage repository capabilities. 195 OE.PUBLIC 196 This environmental security objective is necessary to support the assumption: A.PUBLIC because it requires that the TOE, the SGMI operating system and the authentication server do not host public data. 197 OE.NOEVIL 198 This environmental security objective is necessary to support the assumption: A.NOEVIL because it requires that Authorised administrators are non-hostile and follow all administrator guidance; however, they are capable of error. 199 OE.SINGEN 200 This environmental security objective is necessary to support the assumption: A.SINGEN because it requires that information cannot flow among the internal and external networks unless it passes through the TOE. 201 OE.DIRECT 202 This environmental security objective is necessary to support the assumption: A.DIRECT because it requires that 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. Issue 1.0a Page 57 of 77 22 Mar 2006 Ref.: SGS3\ST 203 OE.NOREMO 204 This environmental security objective is necessary to support the assumption: A.NOREMO because it requires that human users who are not authorised administrators can not access the TOE, the SGMI operating system or the authentication server remotely from the internal or external networks. 205 OE.GUIDAN 206 This environmental security objective is necessary to counter the threat: TE.USAGE and T.AUDACC because it requires that those responsible for the TOE ensure that it is delivered to the user's site, installed, administered, and operated in a secure manner. 207 OE.ADMTRA 208 This environmental security objective is necessary to counter the threat: TE.USAGE and T.AUDACC because it ensures that authorised administrators receive the proper training. 209 OE.REMOS 210 This environmental security objective is necessary to support the assumption: A.REMOS because it requires that the SGMI operating system and the authentication server are delivered to the user's site, installed and administered in a secure manner. 211 OE.COMMS 212 This environmental security objective is necessary to support the assumption: A.COMMS because it requires that the communication links between the TOE, SGMI operating system and the authentication server are physically protected. 213 The following are justifications for IT security threats that are partially met by the TOE and partially by the IT Environment. 214 T.NOAUTH 215 The TOE ensures all FTP and Telnet attempts from an internal or external network are authenticated using an authentication server. Only authenticated connections are allowed between the networks. 216 The SGMI operating system identifies and authenticates users before allowing access to the TOE. Page 58 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 217 T.SELPRO 218 Access to the internal data of the TOE is only possible through the machine that the TOE is installed on. The TOE relies on the physical environment to ensure that only the authorised user has physical access to the TOE. 219 The Linux operating system relies on the physical environment to ensure that only the authorised user has physical access to the Linux operating system. 220 T.AUDFUL 221 The TOE provides the administrator with Read Only access to the TOE audit data through the SGMI. The TOE informs the administrator when the space is reaching its limit. Once the audit trail is full, all connections to the TOE are dropped. 222 The Linux operating system informs the administrator when the audit storage space is reaching its limit. 223 The authorised user of the machine must ensure that the data is archived and that the storage space does not become exhausted. 224 T.AUDACC 225 The TOE through the SGMI provides the administrator with the means to configure the security-related functions and the information flows to be audited. The TOE will audit all attempts by hosts, connected through one network interface, to access hosts or services, connected on another interface, that are not explicitly allowed by the information flow policy. The administrator must ensure that the audit facilities are used and managed correctly including inspecting the logs on a regular basis. 226 The Linux operating system through the administrative tools allows the administrator to configure the security-related functions to be recorded in the audit trail. The administrator must ensure that the audit facilities are used and managed correctly including inspecting the logs on a regular basis. 227 T.LOWEXP 228 The TOE minimizes the threat of malicious attacks by setting the initial settings to deny. The authorised administrator is required to enable the required settings. 229 The Linux operating system, SGMI operating system and the authentication server provide part of the security to ensure that the threat of malicious attack is low, in particular no other applications should be loaded onto the Linux operating system, SGMI operating system and the authentication server. Issue 1.0a Page 59 of 77 22 Mar 2006 Ref.: SGS3\ST 230 T.REPEAT 231 The TOE invokes the authentication server for single use authentication. All attempts are audited. 232 The authentication server ensures that users using FTP or Telnet are authenticated by means of an authentication server that generates a one-time password. 233 The SGMI operating system authenticates authorised administrators prior to allowing an administrator access to TOE. 234 T.REPLAY 235 The TOE invokes the authentication server for single use authentication. All attempts are audited 236 The authentication server ensures that users using FTP or Telnet are authenticated by means of an authentication server that generates a one-time password. 237 The SGMI operating system authenticates authorised administrators prior to allowing an administrator access to TOE. 8.3 Security Requirements Rationale 8.3.1 Security Requirements are appropriate 238 Table 8-2 identifies which SFRs satisfy the Objectives as defined in Section 4.1.1. Objective Security Functional Requirement(s) O.IDAUTH FIA_UAU_SERV.1 O.SINUSE FIA_UAU_SERV.1 O.MEDIAT FDP_IFC.1(1), FDP_IFC.1(2), FDP_IFF.1(1), FDP_IFF.1(2), FMT_MSA.1(1), FMT_MSA.1(2), FMT_MSA.1(3), FMT_MSA.1(4), FMT_MSA.3, FMT_SMF.1(1) O.SECSTA FMT_MSA.1(1), FMT_MSA.1(2), FMT_MSA.1(3), FMT_MSA.1(4), FMT_MSA.3, FPT_RVM.1, FPT_SEP.1, FAU_STG.4, FMT_MOF.1(1), Page 60 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Objective Security Functional Requirement(s) FMT_MOF.1(2), FMT_SMF.1(1) O.SELPRO FPT_RVM.1, FPT_SEP.1, FAU_STG.4 O.AUDREC FAU_GEN.1, FAU_SAR.1, FAU_SAR.3 O.ACCOUN FAU_GEN.1 O.SECFUN FMT_MSA.1(1), FMT_MSA.1(2), FMT_MSA.1(3), FMT_MSA.1(4), FAU_STG.4, FMT_MOF.1(1), FMT_MOF.1(2), FMT_SMF.1(1) O.LIMEXT FMT_MOF.1(1), FMT_MOF.1(2), FMT_SMF.1(1) O.EAL FIA_UAU_SERV.1, FDP_IFC.1(1), FDP_IFC.1(2), FDP_IFF.1(1), FDP_IFF.1(2), FMT_MSA.1(1), FMT_MSA.1(2), FMT_MSA.1(3), FMT_MSA.1(4), FMT_MSA.3, FPT_RVM.1, FPT_SEP.1, FAU_STG.4, FMT_MOF.1(1), FMT_MOF.1(2), FAU_GEN.1, FAU_SAR.1, FAU_SAR.3, FMT_SMF.1(1) Table 8-2 Mapping of Objectives to SFRs 239 O.EAL 240 O.EAL is concerned with the TOE being resistant to obvious vulnerabilities. By default O.EAL maps to all the Security Function Requirements. 241 FIA_UAU_SERV.1 Single-use authentication server 242 This component ensures that an authentication server is appropriately used for Single-use authentication in all attempts to authenticate at the TOE from an internal or external network. This component traces back to and aids in meeting the following objectives: O.SINUSE and O.IDAUTH. 243 FDP_IFC.1 Subset information flow control (1) 244 This component identifies the entities involved in the UNAUTHENTICATED information flow control SFP (i.e., users sending information to other users and vice versa). This component traces back to and aids in meeting the following objective: O.MEDIAT. Issue 1.0a Page 61 of 77 22 Mar 2006 Ref.: SGS3\ST 245 FDP_IFC.1 Subset information flow control (2) 246 This component identifies the entities involved in the AUTHENTICATED information flow control SFP (i.e., users of the services FTP or Telnet sending information to servers and vice versa). The users of these services must be authenticated at the TOE. This component traces back to and aids in meeting the following objective: O.MEDIAT. 247 FDP_IFF.1 Simple security attributes (1) 248 This component identifies the attributes of the users sending and receiving the information in the UNAUTHENTICAED SFP, as well as the attributes for the information itself. Then the policy is defined by saying under what conditions information is permitted to flow. This component traces back to and aids in meeting the following objective: O.MEDIAT. 249 FDP_IFF.1 Simple security attributes (2) 250 This component identifies the attributes of the users sending and receiving the information in the AUTHENTICAED SFP, as well as the attributes for the information itself. Then the policy is defined by saying under what conditions information is permitted to flow. This component traces back to and aids in meeting the following objective: O.MEDIAT. 251 FMT_MSA.1 Management of security attributes (1) 252 This component ensures the TSF enforces the UNAUTHENTICATED_SFP to restrict the ability to delete, modify, and add within a rule those security attributes that are listed in section FDP_IFF1.1(1). This component traces back to and aids in meeting the following objectives: O.MEDIAT, O.SECSTA, and O.SECFUN. 253 FMT_MSA.1 Management of security attributes (2) 254 This component ensures the TSF enforces the AUTHENTICATED_SFP to restrict the ability to delete, modify, and add within a rule those specified security attributes that are listed in section FDP_IFF1.1(2). This component traces back to and aids in meeting the following objectives: O.MEDIAT, O.SECSTA, and O.SECFUN. 255 FMT_MSA.1 Management of security attributes (3) 256 This component ensures the TSF enforces the UNAUTHENTICATED_SFP to restrict the ability to create or delete rules for security attributes that are listed in FDP_IFF.1(1). This component traces back to and aids in meeting the following objectives: O.MEDIAT, O.SECSTA, and O.SECFUN. Page 62 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 257 FMT_MSA.1 Management of security attributes (4) 258 This component ensures the TSF enforces the AUTHENTICATED_SFP to restrict the ability to create or delete rules for security attributes that are listed in FDP_IFF.1(2). This component traces back to and aids in meeting the following objectives: O.MEDIAT, O.SECSTA, and O.SECFUN. 259 FMT_MSA.3 Static attribute initialization 260 This component ensures that there is a default deny policy for the information flow control security rules. This component traces back to and aids in meeting the following objectives: O.MEDIAT and O.SECSTA. 261 FMT_SMF.1 Specification of Management Functions (1) 262 This component ensures that the TSF provide specific security functions. This component traces back to and aids in meeting the following objectives: O.MEDIAT, O.SECSTA, O.SECFUN and O.LIMEXT. 263 FPT_RVM.1 Non-bypassability of the TSP 264 This component ensures that the TSF are always invoked. This component traces back to and aids in meeting the following objective: O.SELPRO and O.SECSTA. 265 FPT_SEP.1 TSF domain separation 266 This component ensures that the TSF have a domain of execution that is separate and that cannot be violated by unauthorised users. This component traces back to and aids in meeting the following objective: O.SELPRO and O.SECSTA. 267 FAU_GEN.1 Audit data generation 268 This component outlines what data must be included in audit records and what events must be audited. This component traces back to and aids in meeting the following objectives: O.AUDREC and O.ACCOUN. 269 FAU_SAR.1 Audit review 270 This component ensures that the audit trail is understandable. This component traces back to and aids in meeting the following objective: O.AUDREC. 271 FAU_SAR.3 Selectable audit review 272 This component ensures that a variety of searches and sorts can be performed on the audit trail. This component traces back to and aids in meeting the following objective: O.AUDREC. Issue 1.0a Page 63 of 77 22 Mar 2006 Ref.: SGS3\ST 273 FAU_STG.4 Prevention of audit data loss 274 This component ensures that the authorised administrator will be able to take care of the audit trail if it should become full. But this component also ensures that no other auditable events as defined in FAU_GEN.1 occur. Thus the authorised administrator is permitted to perform potentially auditable actions though these events will not be recorded until the audit trail is restored to a non-full status. This component traces back to and aids in meeting the following objectives: O.SELPRO, O.SECFUN and O.SECSTA. 275 FMT_MOF.1 Management of security functions behavior (1) 276 This component ensures that the TSF restricts the ability of the TOE start up and shut down operation and the single-use authentication function to the authorised administrator. This component traces back to and aids in meeting the following objectives: O.SECFUN, O.LIMEXT, and O.SECSTA. 277 FMT_MOF.1 Management of security functions behavior (2) 278 This component ensures that the TSF restricts the ability to modify the behavior of functions such as audit trail management, back and restore for TSF data, and communication of authorised external IT entities with the TOE to an authorised administrator. This component traces back to and aids in meeting the following objectives: O.SECFUN, O.LIMEXT, and O.SECSTA. 8.3.2 Environmental Security Requirements are appropriate 279 Table 8-3 identifies which environmental SFRs satisfy the Objectives as defined in Sections 4.1.1 and 4.2.1 Objective Security Functional Requirement(s) O.IDAUTH FIA_UAU.4 O.SINUSE FIA_UAU.4, FIA_UAU.2, FIA_UID.2 O.SECSTA FPT_SEP.1, FAU_STG.1, FMT_MOF.1(3), FMT_SMF.1(2), FIA_UAU.2, FIA_UID.2 O.SELPRO FPT_SEP.1, FAU_STG.1, FIA_UAU.2, FIA_UID.2 O.AUDREC FAU_GEN.1, FPT_STM.1 O.ACCOUN FAU_GEN.1, FPT_STM.1 O.SECFUN FAU_STG.1, FMT_MOF.1(3), FMT_SMF.1(2), Page 64 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Objective Security Functional Requirement(s) FIA_UAU.2, FIA_UID.2 O.LIMEXT FMT_MOF.1(3), FMT_SMF.1(2), FIA_UAU.2, FIA_UID.2 O.EAL FPT_SEP.1, FAU_STG.1, FMT_MOF.1(3), FMT_SMF.1(2), FAU_GEN.1, FPT_STM.1, FIA_UAU.2, FIA_UID.2, FIA_UAU.4 OE.LOWEXP FPT_SEP.1 OE.GENPUR FPT_SEP.1 OE.PUBLIC FPT_SEP.1 OE.SINGEN FPT_SEP.1 OE.NOREMO FPT_SEP.1 Table 8-3 Mapping of Objectives to environmental SFRs 280 O.EAL 281 O.EAL is concerned with the TOE being resistant to obvious vulnerabilities. By default O.EAL maps to all the Security Function Requirements. 282 FIA_UAU.4 Single-use authentication mechanisms 283 This component ensures that a Single-use authentication mechanism is used appropriately in all attempts to authenticate at the TOE from an internal or external network. This component traces back to and aids in meeting the following objectives: O.SINUSE and O.IDAUTH. 284 FPT_SEP.1 TSF domain separation 285 This component ensures that the TSF have a domain of execution that is separate and that cannot be violated by unauthorised users. This component traces back to and aids in meeting the following objectives: O.SELPRO, O.SECSTA, OE.LOWEXP, OE.GENPUR, OE.PUBLIC, OE.SINGEN AND OE.NOREMO. 286 FAU_GEN.1 Audit data generation Issue 1.0a Page 65 of 77 22 Mar 2006 Ref.: SGS3\ST 287 This component outlines what data must be included in audit records and what events must be audited. This component traces back to and aids in meeting the following objectives: O.AUDREC and O.ACCOUN. 288 FPT_STM.1 Reliable time stamps 289 This component ensures that time stamping is enabled. This component traces back to and aids in meeting the following objectives: O.AUDREC and O.ACCOUN. 290 FAU_STG.1 Protected audit trail storage 291 This component ensures that the audit records are protected from unauthorised deletion and modification to the audit records. This component traces back to and aids in meeting the following objectives: O.SELPRO, O.SECFUN and O.SECSTA. 292 FMT_MOF.1 Management of security functions behavior (3) 293 This component ensures that the TSF restricts the ability of the single-use authentication function on the authentication server to the authorised administrator. This component traces back to and aids in meeting the following objectives: O.SECFUN, O.LIMEXT, and O.SECSTA. 294 FMT_SMF.1 Specification of Management Functions (2) 295 This component ensures that that the TSF provides specific security functions. This component traces back to and aids in meeting the following objectives: O.SECSTA, O.SECFUN and O.LIMEXT. 296 FIA_UAU.2 User authentication before any action 297 This component ensures that before anything occurs on behalf of a user, the user is authenticated via the SGMI operating system to the TOE. This component traces back to and aids in meeting the following objectives: O.SINUSE, O.SECSTA, O.SELPRO, O.SECFUN and O.LIMEXT 298 FIA_UID.2 User identification before any action 299 This component ensures that before anything occurs on behalf of a user, the user's identity is identified via the SGMI operating system to the TOE. This component traces back to and aids in meeting the following objectives: O.SINUSE, O.SECSTA, O.SELPRO, O.SECFUN and O.LIMEXT. Page 66 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 8.3.3 Security Requirement dependencies are satisfied Functional Component Dependencies SFR(s) in Security Target meeting Dependencies FMT_MSA.1 [FDP_ACC.1 or FDP_IFC.1], FMT_SMR.1 FMT_SMF.1 FDP_IFC.1 See note below regarding FMT_SMR.1. FMT_SMF.1 FMT_MSA.1 [FDP_ACC.1 or FDP_IFC.1], FMT_SMR.1 FMT_SMF.1 FDP_IFC.1 See note below regarding FMT_SMR.1. FMT_SMF.1 FMT_MSA.1 [FDP_ACC.1 or FDP_IFC.1], FMT_SMR.1 FMT_SMF.1 FDP_IFC.1 See note below regarding FMT_SMR.1. FMT_SMF.1 FMT_MSA.1 [FDP_ACC.1 or FDP_IFC.1], FMT_SMR.1 FMT_SMF.1 FDP_IFC.1 See note below regarding FMT_SMR.1. FMT_SMF.1 FMT_MSA.3 FMT_MSA.1, FMT_SMR.1 FMT_MSA.1 See note below regarding FMT_SMR.1. FMT_MOF.1 FMT_SMR.1 FMT_SMF.1 See note below regarding FMT_SMR.1. FMT_SMF.1 FMT_MOF.1 FMT_SMR.1 FMT_SMF.1 See note below regarding FMT_SMR.1. FMT_SMF.1 FMT_SMF.1 NONE NONE FAU_GEN.1 FPT_STM.1 FPT_STM.1 FAU_SAR.1 FAU_GEN.1 FAU_GEN.1 Issue 1.0a Page 67 of 77 22 Mar 2006 Ref.: SGS3\ST Functional Component Dependencies SFR(s) in Security Target meeting Dependencies FAU_SAR.3 FAU_SAR.1 FAU_SAR.1 FAU_STG.1xvi FAU_GEN.1 FAU_GEN.1 FAU_STG.4 FAU_STG.1 FAU_STG.1 FDP_IFC.1 FDP_IFF.1 FDP_IFF.1 FDP_IFC.1 FDP_IFF.1 FDP_IFF.1 FDP_IFF.1 FDP_IFC.1, FMT_MSA.3 FDP_IFC.1, FMT_MSA.3 FDP_IFF.1 FDP_IFC.1, FMT_MSA.3 FDP_IFC.1, FMT_MSA.3 FPT_RVM.1 None None FPT_SEP.1 None None FPT_STM.1xvii None None FIA_UAU_SERV.1 xviii FIA_UAU.4 FIA_UAU.4xix FIA_UAU.4xx None None Table 8-4 Mapping of TOE SFR Dependencies 300 The security functional requirements are hierarchical and may satisfy the dependency. 301 FMT_MSA.1, FMT_MSA.3, and FMT_MOF.1 have a dependency on FMT_SMR.1. For security management of the TOE, as stated in objective OE.PHYSEC and OE.NOREMO only an authorised administrator will have xvi FAU_STG.1 is a security requirement for the IT environment. xvii FPT_STM.1 is a security requirement for the IT environment. xviii FIA_UAU_SERV.1 is an explicitly stated requirement. xix FIA_UAU.4 is a security requirement for the IT environment. xx FIA_UAU.4 is a security requirement for the IT environment. Page 68 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 physical access to the TOE, SGMI workstation and the authentication server. Human users, including authorised administrators can not access the TOE, SGMI workstation or the authentication server remotely from the internal or external networks. The dependency on FMT_SMR.1 is therefore regarded as satisfied. 8.3.4 IT security functions satisfy SFRs 302 Mapping of Section 6 IT functions to SFRs (Section 5.1 and 5.2). IT Function Security Functional Requirement(s) Identification and Authentication IA1 FIA_UAU_SERV.1 Management and Securityxxi MT1 FMT_MSA.1(1), FMT_SMF.1(1) MT2 FMT_MSA.1(2) , FMT_SMF.1(1) MT3 FMT_MSA.1(3) , FMT_SMF.1(1) MT4 FMT_MSA.1(4) , FMT_SMF.1(1) MT5 FMT_MSA.3 MT6 FMT_MOF.1(1) , FMT_SMF.1(1) MT7 FMT_MOF.1 (2), FMT_SMF.1(1) MT8 FMT_MSA.3 Audit AU1 FAU_GEN.1 AU2 FAU_GEN.1 AU3 FAU_GEN.1 AU4 FAU_SAR.1 xxi FAU_GEN.1 Table 5-2 is applicable to FMT_SMF.1, and FMT_MOF.1 (1), (2) Issue 1.0a Page 69 of 77 22 Mar 2006 Ref.: SGS3\ST AU5 FAU_SAR.3, FAU_SAR.1 AU6 FAU_STG.4 Protection of TOE Security Functions PT1 FPT_SEP.1 PT2 FPT_RVM.1 PT3 FPT_RVM.1 User Data Protectionxxii 6 DP1 FDP_IFF.1 (2) DP2 FDP_IFC.1 (1), FDP_IFC.1 (2), FDP_IFF.1 (1), FDP_IFF.1 (2) DP3 FDP_IFC.1 (2), FDP_IFF.1 (1) DP4 FDP_IFC.1 (1), FDP_IFC.1 (2), FDP_IFF.1 (1), FDP_IFF.1 (2) DP5 FDP_IFC.1 (1), FDP_IFC.1 (2), FDP_IFF.1 (1), FDP_IFF.1 (2) DP6 FDP_IFC.1 (1), FDP_IFC.1 (2), FDP_IFF.1 (1), FDP_IFF.1 (2) DP7 FDP_IFC.1 (1), FDP_IFC.1 (2), FDP_IFF.1 (1), FDP_IFF.1 (2) DP8 FDP_IFC.1 (1), FDP_IFC.1 (2) DP9 FDP_IFF.1 (1) , FDP_IFF.1 (2) DP10 FDP_IFF.1 (1) DP11 FDP_IFC.1 (1) xxii FAU_GEN.1 Table 5-2 is applicable to FDP_IFF.1 Page 70 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 DP12 FDP_IFF.1 (1) DP13 FDP_IFF.1 (1) DP14 FDP_IFF.1 (1) DP15 FDP_IFF.1 (1) DP16 FDP_IFF.1 (1) DP17 FDP_IFF.1 (1) DP18 FDP_IFF.1 (1) DP19 FDP_IFF.1 (1) DP20 FDP_IFF.1 (1) DP21 FDP_IFF.1 (1) DP22 FDP_IFF.1 (1) DP23 FDP_IFF.1 (1) DP24 FDP_IFF.1 (1) DP25 FDP_IFF.1 (2) DP26 FDP_IFC.1 (2) DP27 FDP_IFF.1 (2) DP28 FDP_IFF.1 (2) DP29 FDP_IFF.1 (2) DP30 FDP_IFF.1 (2) DP31 FDP_IFF.1 (2) DP32 FDP_IFF.1 (2) DP33 FDP_IFF.1 (2) DP34 FDP_IFF.1 (2) DP35 FDP_IFF.1 (2) Issue 1.0a Page 71 of 77 22 Mar 2006 Ref.: SGS3\ST DP36 FDP_IFF.1 (2) DP37 FDP_IFF.1 (2) DP38 FDP_IFF.1 (2) DP39 FDP_IFF.1 (2) DP40 FDP_IFF.1 (2) DP41 FDP_IFF.1 (2) Table 8-5 Mapping of IT Functions to SFRs 303 To perform searches and sorts on the audit database the administrator will be able to use the Security Gateway Management Interface (SGMI) Logfile icon. This is to meet FAU_SAR.1. In the event of audit storage failure, exhaustion and / or attack the TOE will stop all connections through the TOE and so the amount of data to be lost is none. So that requirement FAU_STG.4 is met. 304 Once the audit trail becomes full, the TSF drops all connections through the TOE. Therefore the maximum amount of audit data to be lost is zero. 305 Table 8-5 demonstrates that the IT security functions map to TOE Security Functional Requirements provided by the TSS. Each of the IT Security Functions maps to at least one TOE security function, and all the TOE Security Function Requirements are covered. Therefore by implementing all the IT Security Functions, the TOE Functional Requirement is met. 8.3.5 IT security functions mutually supportive 306 The mutually supportive nature of the IT security functions can be derived from the mutual support of the SFRs (demonstrated in Section 8.3.3), as each of the IT functions can be mapped to one or more SFRs, as demonstrated in Table 8-5. 8.3.6 Justification of Explicit Requirements 307 The explicit requirement FIA_UAU_SERV.1 has been specified to address the requirement for the TOE to invoke an authentication server to authenticate any human user's claimed identity when using FTP or Telnet prior to gaining access to the TOE. The single-use authentication mechanism is part of the IT environment. Page 72 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 8.3.7 Strength of Function claims are appropriate 308 The SOF claim made by the TOE is SOF-medium. 309 Products such as the SGS 5000 series Version 3.0 (Firewall Engine Only) are intended to be used in a variety of environments and used to connect networks with different levels of trust in the users. A number of deployments are possible. The Strength of Function of SOF-Medium for the TOE will be appropriate to a number of deployments, in both government and other organisations. 8.3.8 Justification of Assurance Requirements 310 EAL4 is defined in the CC as “methodically designed, tested and reviewed”. 311 Products such as the SGS 5000 series Version 3.0 (Firewall Engine Only) are intended to be used in a variety of environments, and used to connect networks with different levels of trust in the users. A number of deployments are possible. The EAL4 assurance level will be appropriate to a number to a number of deployments, in both government and other organisations. 312 ALC_FLR.1 is appropriate to demonstrate the tracking and correction of flaws in products such as SGS that may have to be updated to address ever evolving methods of attack. 8.3.9 Assurance measures satisfy assurance requirements 313 Assurance measures in the form of deliverables will be produced to meet EAL4 assurance requirements, augmented with ALC_FLR.1. 314 Table 8-6, below, provides a tracing of the Assurance Measures to the assurance requirements that they meet. From the table it can be seen that all assurance requirements trace to at least one assurance measure. 315 The assurance requirements identified in the table are those required to meet the CC assurance level EAL4, augmented with ALC_FLR.1. As all assurance requirements are traced to at least one of the assurance measures, the identified assurance measures are sufficient to meet the assurance requirements. It is also asserted that the assurance measures have been produced with EAL4, augmented with ALC_FLR.1 in mind and as a consequence contains sufficient information to meet the assurance requirements of the TOE. Issue 1.0a Page 73 of 77 22 Mar 2006 Ref.: SGS3\ST Assurance Measures Assurance Requirements Met by Assurance Measure The implementation and documentation of procedures for the development of the TOE. Included in the procedures are: • The use of an automated configuration management system to support the secure development of the TOE, with user restrictions. • Procedures for authorising changes and implementing changes. ACM_AUT.1 Partial CM automation • Procedures for tracking problems and rectification of problems. ACM_CAP.4 Generation support and acceptance procedures ACM_SCP.2 Problem tracking CM coverage The implementation and documentation of procedures for delivering the TOE to a customer in a secure manner. ADO_DEL.2 Detection of modification Page 74 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Assurance Measures Assurance Requirements Met by Assurance Measure Documentation provided to the customers instructing the customer how to install and configure the TOE in a secure manner. ADO_IGS.1 Installation, generation and start-up procedures The implementation and documentation of procedures for the life-cycle model used to develop the TOE. ALC_LCD.1 Developer defined life-cycle model Functional Specification for the TOE describing the TSF and the TOE's external interfaces. ADV_FSP.2 Fully defined external interfaces System Design for the TOE providing descriptions of the TSF structure in the form of subsystems and the functionality of each subsystem. ADV_HLD.2 Security enforcing high-level design Various source code modules for the SGS 5000 series Version 3.0 (Firewall Engine Only) ADV_IMP.1 Subset of the implementation of the TSF System Design for the TOE providing descriptions of the TSF in the form of modules. ADV_LLD.1 Descriptive low-level design The documentation of the correspondence between all the TSF representations in specifically provided deliverables. ADV_RCR.1 Informal correspondence demonstration Documented Security Policy Model ADV_SPM.1 Informal TOE security policy model Issue 1.0a Page 75 of 77 22 Mar 2006 Ref.: SGS3\ST Assurance Measures Assurance Requirements Met by Assurance Measure Documentation provided to the customers instructing the customer how to configure the TOE in a secure manner. AGD_ADM.1 Administrator guidance No specific user documentation is relevant as there are no non- administrative users. AGD_USR.1 User guidance The implementation and documentation of the physical security procedures to ensure the secure development of the TOE. ALC_DVS.1 Identification of security measures The implementation and documentation of procedures for tracking and rectifying flaws. ALC_FLR.1 Basic Flaw Remediation The implementation and documentation of the tools used to develop the TOE. ALC_TAT.1 Well-defined development tools Documented correspondence between the security functions and tests. ATE_COV.2 Analysis of coverage Documented correspondence between the High-level design subsystems and tests. ATE_DPT.1 Testing: high-level design The implementation and documentation of the test procedures including expected and actual results. ATE_FUN.1 Functional testing Independent Testing Resources ATE_IND.2 Independent testing Page 76 of 77 Issue 1.0a Ref.: SGS3\ST 22 Mar 2006 Assurance Measures Assurance Requirements Met by Assurance Measure Misuse Analysis is performed and documented to ensure that the guidance documents supplied are sufficient to ensure that the TOE can not be used in a insecure manner. AVA_MSU.2 Validation of analysis Strength of Function Assessment of the authentication mechanism is performed and documented to gain confidence in the security functionality of the TOE. AVA_SOF.1 Strength of TOE security function evaluation Vulnerability Assessment of the TOE and it's deliverables is performed documented to ensure that identified security flaws are countered. AVA_VLA.2 Independent vulnerability analysis Table 8-6 Mapping of Assurance Measures to Assurance Requirements Issue 1.0a Page 77 of 77 22 Mar 2006 Ref.: SGS3\ST This page is intentionally blank.