Security Target
Version 1.0
packet filter 5.1.0
Certification-ID: BSI-DSZ-CC-0991
Authors: Christian Koob, Jörg Marx, Martin Matthes
Version 1.0, 03/08/2016
secunet Security Networks AG
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Copyright © 2016 by secunet Security Networks AG
Use of customary names, trade names, trademarks etc. in this document does not give rise to any
presumption that such names are to be regarded as being free within the meaning of the trademark
and brand protection acts. All brand and product are trademarks or registered trademarks of their
respective owners.
Documentation history
Version Date Change(s) Author(s)
0.91 09/04/2015 Version for packet filter 5.1.0 with Comments from
evaluation facility:
- Component instead module
- A.SECINIT und OE.SECINIT deleted
- Only SSH in environment
- Rationale for T.BYPASS changed
Martin Matthes
1.0 03/08/2016 - New document template added
- Copyright changed
Martin Matthes,
Christian Koob
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Contents
Contents................................................................................................................................ 3
List of Tables......................................................................................................................... 5
1 ST INTRODUCTION...................................................................................................... 6
1.1 ST reference and TOE reference ........................................................................ 6
1.2 TOE Overview..................................................................................................... 6
1.2.1 Usage, major security features and TOE type ....................................... 6
1.2.2 Required non TOE hardware/software/firmware .................................... 8
1.3 TOE Description.................................................................................................. 9
1.3.1 Physical scope of the TOE .................................................................... 9
1.3.2 Logical scope of the TOE ...................................................................... 9
1.3.2.1 Audit Data.............................................................................................. 9
1.3.2.2 Information Flow Protection ................................................................... 9
1.3.2.3 Management ........................................................................................10
1.3.2.4 Components.........................................................................................10
2 CONFORMANCE CLAIM .............................................................................................11
2.1 CC Conformance Claim .....................................................................................11
2.2 PP and security requirement package claim.......................................................11
2.3 CC Conformance Claim Rationale......................................................................11
3 SECURITY PROBLEM DEFINITION ............................................................................12
3.1 Assets................................................................................................................12
3.2 Subjects .............................................................................................................13
3.3 External entities..................................................................................................13
3.4 Assumptions ......................................................................................................14
3.5 Threats...............................................................................................................15
3.6 Organisational security policies ..........................................................................15
4 STATEMENT OF SECURITY OBJECTIVES ................................................................16
4.1 Security Objectives for the TOE .........................................................................16
4.2 Security Objectives for the Operational Environment..........................................17
4.3 Security Objectives Rationale.............................................................................18
4.3.1 Countering the threats ..........................................................................19
4.3.2 Covering the OSPs...............................................................................19
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4.3.3 Covering the assumptions ....................................................................19
5 STATEMENT OF SECURITY REQUIREMENTS..........................................................20
5.1 Security functional requirements for the TOE .....................................................20
5.1.1 Security Audit .......................................................................................21
5.1.1.1 FAU_GEN.1 Audit data generation.......................................................21
5.1.2 User data protection (FDP)...................................................................21
5.1.2.1 FDP_IFC.1 Subset information flow control ..........................................21
5.1.2.2 FDP_IFF.1 Simple security attributes ...................................................22
5.1.3 User identification (UID)........................................................................23
5.1.3.1 FIA_UID.1 Timing of identification ........................................................23
5.1.4 Security management (FMT) ................................................................25
5.1.4.1 FMT_MSA.1 Management of security attributes ...................................25
5.1.4.2 FMT_MSA.3 Static attribute initialization ..............................................25
5.1.4.3 FMT_SMF.1 Specification of management functions............................26
5.1.4.4 FMT_SMR.1 Security roles...................................................................26
5.2 Extended Components definition........................................................................26
5.3 Security assurance requirements for the TOE....................................................27
5.4 Security Requirements Rationale .......................................................................28
5.4.1 TOE functional requirements rationale..................................................28
5.4.2 Fulfilling the SFR dependencies ...........................................................29
5.4.3 Security assurance requirements rationale...........................................29
6 TOE SUMMARY SPECIFICATION...............................................................................30
6.1 TOE security functionality...................................................................................30
6.1.1 SF1 Information Flow Protection...........................................................30
6.1.2 SF2 Security Audit................................................................................30
6.1.3 SF3 Management.................................................................................31
7 GLOSSARY AND ACRONYMS....................................................................................32
8 REFERENCES.............................................................................................................33
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List of Tables
Table 1: Scope of TOE delivery............................................................................................. 9
Table 2: secunet wall packet filter components ....................................................................10
Table 3: Assets ....................................................................................................................12
Table 4: External entities......................................................................................................13
Table 5: Assumptions...........................................................................................................14
Table 6: Threats ...................................................................................................................15
Table 7: Security Objectives for the TOE..............................................................................16
Table 8: Security Objectives for the environment of the TOE................................................17
Table 9: Security Objective Rationale...................................................................................18
Table 10: Security Functional Requirements for the TOE.....................................................20
Table 11: Chosen Evaluation Assurance Requirements.......................................................27
Table 12: Coverage of Security Objective for the TOE by SFR.............................................28
Table 13: Fulfilling the SFR dependencies ...........................................................................29
List of Figures
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1 ST INTRODUCTION
1.1 ST reference and TOE reference
Title: secunet wall packet filter Security Target
Sponsor: secunet Security Networks AG
Editor(s): Christian Koob, Jörg Marx, Martin Matthes, secunet Security Networks-AG
Version Number: 1.0
Date: 08.03.2016
CC Version: Version 3.1, Revision 4
Assurance Level: EAL4+, that is EAL4 augmented by ALC_FLR.2
Certification-ID: BSI-DSZ-CC-0991
Keywords: Firewall, Packet Filter, Network Security, Information flow control
TOE name: secunet wall packet filter
TOE version: Version 5.1.0
1.2 TOE Overview
1.2.1 Usage, major security features and TOE type
This Security Target defines the security objectives and requirements for the secunet wall packet filter
(TOE), a software component of secunet Security Networks AG. secunet wall packet filter provides
packet filter functionality. secunet wall packet filter allows the integration of packet filter capability into
firewall or VPN components which are parts of secunet wall or SINA product family. Thus the secunet
wall packet filter is delivered to an application developer. The application developer integrates the
secunet wall packet filter into an application in order to build a network component. The administrator
of this application is defined as TOE end-user.
When IP networks with different levels of security are interconnected, this is usually done by
introducing special network components at the border of the networks. These components provide
firewall functionality and separate the two or more networks from each other on different levels of the
network stack. Data flow from one to another network can be allowed by a rule based policy enforced
by these network components.
The secunet wall packet filter consists of software on machines to implement packet filter functionality
for the network components; i. e. the secunet wall packet filter is part of the network components. The
secunet wall packet filter relies on information available at OSI layer 3 and layer 4 for policy
enforcement. The functionality for packet filtering is part of the operating system (Linux). The secunet
wall packet filter supports IPv4 [4].
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The TOE major security features are:
 The TOE enforces the Packet Filter information flow policy. This policy ensures that the TOE will
only forward data from and to the internal network if the information flow policy allows it.
 The TOE collects audit data and sends it to a memory buffer in order to identify attempts to violate
a policy.
 The TOE is capable of performing management functions such as modification of networks filter
traffic rules and configuration data.
 The TOE verifies the identification information of an administrator provided by the environment
(application) before any management function can be performed.
The following security services are not part of the TOE and are thus to be provided by the IT
environment (application):
 The environment allows the Identification and Authentication of an administrator
 Sending of audit data to a dedicated machine in the protected network
The generation of networks filter traffic rules (policy) and configuration data takes place in the IT
environment. The IT environment provides NTP service and Syslog service.
After start-up of a network component that comprise the TOE and a secure initialisation process the
initial TOE configuration data is read via I/O-control interface in the TOE system start-up process. The
configuration data is the human readable content of the configuration file. The configuration data
comprise IP address- and network interface definition, static routes and other system parameters. If no
configuration data is available on start-up the TOE will not start-up automatically.
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1.2.2 Required non TOE hardware/software/firmware
The TOE has the following minimal requirements concerning the physical machine they run on:
 Intel i686 compatible CPU
 PCI bus system
 256 MB RAM
 two 1000Mbit Ethernet Interfaces
 storage entity (further requirements depend on the application)
 USB Controller or Compact Flash Adapter
The hardware must be compatible with the Linux operating system used for the application.
The physical connections are:
 power supply
 network interfaces
 PS/2- or USB-attached keyboard
 VGA graphics adapter
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1.3 TOE Description
1.3.1 Physical scope of the TOE
The TOE consists of several components that are all running in Kernel-Space on the Linux operating
system. These components are the following kernel parts: packet filter, management and audit
mechanism. All other parts of the system are considered to be environment of the TOE.
The TOE is delivered to an application developer. The TOE delivery includes the software secunet
wall packet filter and documentation. This documentation contains information for the application
developer and the TOE end-user. See the following table. The software component is electronically
signed.
Delivered TOE parts Version Remarks
secunet wall packet filter CD-ROM Version 5.1.0 secunet wall packet filter Software
documentation Version 1.0 Delivered as PDF on secunet wall packet filter
CD-ROM
Table 1: Scope of TOE delivery
1.3.2 Logical scope of the TOE
1.3.2.1 Audit Data
The TOE collects audit data and sends it to a memory buffer in order to identify attempts to violate a
policy. This allows the authorized administrator to inspect the current state of a network component.
The TOE generates audit records for
 start-up and shutdown of the audit functions
 datagrams received or sent through a network components network interfaces if they match
configured patterns
1.3.2.2 Information Flow Protection
The TOE enforces the Packet Filter information flow policy. This policy ensures that the TOE will only
forward data from and to the internal network if the information flow policy allows it. Therefore the TOE
implements the information flow control (as routers) on the network layer (IP) and transport layer
(TCP/UDP/ICMP). In order to apply the packet filter rules the network components take the
information from the IP and TCP/UDP/ICMP-Header (where applicable).
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1.3.2.3 Management
The TSF is capable of performing the following management functions:
 Modification of network traffic filter rules
 Modification of configuration data
The TOE verifies the identification information of an administrator provided by the environment
(application) before any management function can be performed. The TOE is initialized with a strict
packet filter rule set, i. e. everything is dropped.
1.3.2.4 Components
The secunet wall packet filter consists of several components. Table 2 shows which components are
parts of the TOE and part of the IT environment.
- IT environment TOE
Kernel - Packet filter
Audit mechanism
Management
User Space Secure transport mechanism for
configuration data and audit data.
Management (Configuration Tool)
-
Table 2: secunet wall packet filter components
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2 CONFORMANCE CLAIM
2.1 CC Conformance Claim
This Security Target and the TOE claim conformance to part 2 and part 3 of Common Criteria ([1] and
[2]):
Common Criteria Part 2 conformant
Common Criteria Part 3 conformant
2.2 PP and security requirement package claim
This Security Target does neither claim conformance to a Protection Profile nor to a security
requirement package.
2.3 CC Conformance Claim Rationale
As this Security Target does neither claim conformance to a Protection Profile nor to a security
requirement package a conformance claim rationale is not necessary.
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3 SECURITY PROBLEM DEFINITION
This chapter introduces the security problem definition of the TOE. This comprises:
 The assets which have to be protected by the TOE.
 The subjects which are interacting with the TOE.
 The assumptions which have to be made about the environment of the TOE.
 The threats which exist against the assets of the TOE
 The organisational security policies the TOE has to comply to.
3.1 Assets
The following assets need to be protected by the TOE and its environment:
Asset Description
TSF Data
(Information Flow)
Audit data transmitted from the network components to
the management machine.
Configuration data transmitted from the management
machine to the network components.
TSF Data
(On the TOE)
TSF data stored on the TOE which are necessary for its
own operation. This includes packet filter rules or
configuration data.
Resources The resources in the connected networks that the TOE
components are supposed to protect. The resources
are outside the TOE components.
Table 3: Assets
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3.2 Subjects
No active entity in the TOE that performs operations on objects is defined.
3.3 External entities
The following external entities may interact with the TOE:
External entity Description
Administrator The administrator of a network component is an entity that has complete trust with
respect to all policies implemented by the TSF. He is in charge of installing and
configuring the TOE as well as performing the management functions of the TOE.
User Any entity (human or IT) outside the TOE that interacts (or may interact) with the
TOE. A goal of a user may be to access or
modify sensitive information by sending IP packets to or receiving from the
components of the TOE. This includes attacks from the protected networks behind
the network components as well as attacks from outside those networks. Attackers
with an Enhanced-Basic attack potential are assumed.
Table 4: External entities
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3.4 Assumptions
The following assumptions need to be made about the IT environment of the TOE to allow the secure
operation of the TOE.
Assumption Description
A.ENV The TOE is used in a controlled environment. Specifi-
cally it is assumed:
That only the administrator gains physical access to the
TOE,
That the administrator handles the authentication se-
crets (see A.I&A) with care, specifically that he will keep
them secret and can use it in a way that nobody else
can read it.
A.NOEVIL The administrator of the TOE is non hostile, well trained
and knows the documentation of the TOE.
The administrator is responsible for the secure opera-
tion of the TOE and its environment.
A.INFLOW No information can flow between the internal and ex-
ternal networks unless it passes through the TOE.
A.CONFW The network components (TOE and application) are
configured in a secure manner. Specifically it is as-
sumed that no incoming connections are accepted
except protected data (SSH, [3]) from the management
machine.
A.TSP The IT environment provides reliable timestamps (NTP
server).
A.PROT The data flow between the management machine and
the network components is protected by cryptographic
transforms (SSH authorization and SSH transport pro-
tection as defined in [3]).
A.AUDIT The IT environment provides a Syslog server and a
means to present a readable view of the audit data.
A.I&A The environment allows the Identification and Authenti-
cation of an administrator.
Table 5: Assumptions
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3.5 Threats
The following threats have to be countered by the TOE. Hereby attackers with an enhanced-basic
attack potential are assumed.
Threat Description
T.BYPASS A user might attempt to bypass the security functions of the TOE in order to gain
unauthorized access to resources in the protected networks.
E. g., a user might send non-permissible data through the TOE in order to gain
access to resources in protected networks by sending IP packets to circumvent
filters. This attack may happen from outside the protected network.
T.WEAKNESS A user might gain access to the TOE in order to read, modify or destroy TSF data
by sending IP packets to the TOE and exploiting a weakness of the protocol used.
This attack may happen from outside and inside the protected network. A user
might also try to access sensitive data of the TOE via its management interface.
Table 6: Threats
3.6 Organisational security policies
The TOE does not enforce organisational security policies.
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4 STATEMENT OF SECURITY OBJECTIVES
This chapter describes the security objectives for the TOE (in chapter 4.1), the security objectives for
the operational environment of the TOE (in chapter 4.2) and contains the security objectives rationale.
4.1 Security Objectives for the TOE
The following security objectives have to be met by the TOE
Policy Description
O.MANAGEMENT The TOE verifies the identification information of an administrator provided by the
environment (application) before any management function can be performed. The
TOE must provide the necessary management functions in order to modify the con-
figuration data or the traffic filter rules.
O.FILTER The TOE must filter the incoming and the outgoing data traffic of all data between all
connected networks according to the rule sets.
O.AUDIT The TOE must provide an audit trail of security-related events.
Table 7: Security Objectives for the TOE
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4.2 Security Objectives for the Operational Environment
The following security objectives have to be met by the operational environment of the TOE.
Policy Description
OE.ENV The TOE is used in a controlled environment. Specifically it is assumed:
 That only the administrator gains physical access to the TOE,
 That the administrator handles the authentication secrets (see A.I&A) with care,
specifically that he will keep them secret and can use it in a way that nobody else
can read it.
OE.NOEVIL The administrator of the TOE shall be non hostile, well trained and has to know the
documentation of the TOE.
The administrator is responsible for the secure operation of the TOE and its environ-
ment.
OE.INFLOW The administrator must assure that the packet filter components provide the only con-
nection for the different networks.
OE.CONFW The network components (TOE and application) must be configured to accept only
protected data (SSH, [3]) from the management machine.
OE.TSP The IT environment provides reliable timestamps
(NTP server).
OE.PROT The data flow between the management machine and the network components is pro-
tected by cryptographic transforms (SSH authorization and SSH transport protection as
defined in [3]).
OE.AUDIT The IT environment provides a Syslog server and a means to present a readable view
of the audit data.
OE.I&A The environment allows the Identification and Authentication of an administrator.
Table 8: Security Objectives for the environment of the TOE
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4.3 Security Objectives Rationale
The following table provides an overview for security objectives coverage. The following chapters
provide a more detailed explanation of this mapping.
OE.ENV
OE.NOEVIL
OE.INFLOW
OE.CONFW
OE.TSP
OE.PROT
OE.AUDIT
OE.I&A
O.FILTER
O.AUDIT
O.MANAGEMENT
A.ENV X
A.NOEVIL X
A.INFLOW X
A.CONFW X
A.TSP X
A.PROT X
A.AUDIT X
A.I&A X
T.BYPASS X X X X
T.WEAKNESS X X X X X
Table 9: Security Objective Rationale
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4.3.1 Countering the threats
The threat T.BYPASSSS which describes that an attacker may bypass the security functions of the
TOE in order to gain unauthorized access to resources in the protected networks is countered by a
combination of the objectives OE.PROT, OE.ENV, OE.INFLOW and O.FILTER. The environmental
objectives OE.ENV and OE.INFLOW ensure that a user can neither interfere with the initial setup or
the physical setup of the management machine or network components nor routes around the
management machine or network components. Thus, all data pass through the TOE. O.FILTER
ensures that this data is always checked and filtered according to the policy. The environmental
objective OE.PROT ensures that data flow between the management machine and the network
components is protected by cryptographic transforms, i.e. that sessions of users already authenticated
cannot be taken over.
The threat T.WEAKNESS which describes that an attacker may try to exploit a weakness of the
protocol used in order to read, modify or destroy security sensitive data on the TOE is countered by a
combination of the objectives OE.I&A, O.AUDIT, OE.AUDIT, OE.CONFW and O.MANAGEMENT.
O.AUDIT and OE.AUDIT ensure detection of attempts to compromise the TOE. O.MANAGEMENT
and OE.I&A ensure that only the authorized administrator is able to manage the TSF data and
removes the aspect of the threat where an attacker could try to access sensitive data of the TOE via
its management interface. The environmental objective OE.CONFW ensures that no service beside
SSH run on the network components.
4.3.2 Covering the OSPs
The TOE does not enforce organizational security policies.
4.3.3 Covering the assumptions
The assumption A.ENV is covered by OE.ENV as directly follows.
The assumption A.NOEVIL is covered by OE.NOEVIL as directly follows.
The assumption A.INFLOW is covered by OE.INFLOW as directly follows.
The assumption A.CONFW is covered by OE.CONFW as directly follows.
The assumption A.TSP is covered by OE.TSP as directly follows.
The assumption A.PROT is covered by OE.PROT as directly follows.
The assumption A.AUDIT is covered by OE.AUDIT as directly follows.
The assumption A.I&A is covered by OE.I&A as directly follows.
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5 STATEMENT OF SECURITY REQUIREMENTS
This chapter defines the security functional requirements (see chapter 5.1) and the security assurance
requirements for the TOE (see chapter 5.3). No extended components are defined in this Security
Target (see chapter 5.2).
5.1 Security functional requirements for the TOE
The TOE satisfies the SFRs delineated in the following table. The rest of this chapter contains a
description of each component and any related dependencies.
Security audit (FAU)
FAU_GEN.1 Audit data generation
User data protection (FDP)
FDP_IFC.1 Subset information flow control
FDP_IFF.1 Simple security attributes
User identification (FIA)
FIA_UID.1 Timing of identification
Security management (FMT)
FMT_MSA.1 Management of security attributes
FMT_MSA.3 Static attribute initialisation
FMT_SMF.1 Specification of management functions
FMT_SMR.1 Security roles
Table 10: Security Functional Requirements for the TOE
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5.1.1 Security Audit
5.1.1.1 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) [starting of network components; IP datagrams
matching log filters in packet filter rules]
FAU_GEN.1.2
The TSF shall record within each audit record at least
the following information:
a) Date and time of event, type of event, subject
identity (if applicable), and the outcome (suc-
cess or failure) of the event;
b) and For each audit event type, based on the
auditable event definitions of the functional
components included in the PP/ST, [no other
audit relevant information]
Hierarchical to: No other components
Dependencies FPT_STM.1 Reliable time stamps
5.1.2 User data protection (FDP)
5.1.2.1 FDP_IFC.1 Subset information flow control
FDP_IFC.1.1 The TSF shall enforce the [Packet Filter SFP] on
[Subjects: users (external entities) that send and/or
receive information through the TOE to one another;
Information: data sent from one subject through the
TOE to one another;
Operation: pass the data].
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Hierarchical to: No other components.
Dependencies: FDP_IFF.1 Simple security attributes
Application Note: The Packet Filter SFP is given in FDP_IFF. The subject definition in
FDP_IFC.1.1 belongs to a former CC version. Thus the subjects are identical to the users
defined in the external entities definition in chap. 3.3.
5.1.2.2 FDP_IFF.1 Simple security attributes
FDP_IFF.1.1 The TSF shall enforce the [Packet Filter SFP] based on
the following types of subject and information security
attributes:
[Subjects: users (external entities) that send and/or
receive information through the TOE to one another;
Subject security attributes: none;
Information: data sent from one subject through the
TOE to one another;
Information security attributes: source address of
subject, destination address of subject, transport layer
protocol, interface on which the traffic arrives and
departs, port, time].
FDP_IFF.1.2 The TSF shall permit an information flow between a
controlled subject and controlled information via a
controlled operation if the following rules hold: [Subjects
on a network connected to the TOE can cause
information to flow through the TOE to a subject on
another connected network only if all the information
security attribute values are permitted by all information
policy rules].
FDP_IFF.1.3 The TSF shall enforce the [reassembly of fragmented
IP datagrams before inspection].
FDP_IFF.1.4 The TSF shall explicitly authorise an information flow
based on the following rules: [none].
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FDP_IFF.1.5 The TSF shall explicitly deny an information flow based
on the following rules:
 [The TOE shall reject requests of access or services
where the information arrives on a network interface
and the source address of the requesting subject
does not belong to the network associated with the
interface (spoofed packets);
 The TSF shall drop IP datagrams with the source
routing option;
 The TOE shall reject fragmented IP datagrams
which cannot be reassembled completely within a
bounded interval].
Hierarchical to:
No other components.
Dependencies:
FDP_IFC.1 Subset information flow control
FMT_MSA.3 Static attribute initialisation
Application Note: The subject definition in FDP_IFF.1.1 belongs to a former CC version. Thus the
subjects are identical to the users defined in the external entities definition in chap. 3.3.
5.1.3 User identification (UID)
5.1.3.1 FIA_UID.1 Timing of identification
FIA_UID.1.1 The TSF shall allow [the following TSF-mediated
actions] on behalf of the user to be performed before
the user is identified.
 all actions except for administrative actions as
specified by FMT_SMF.1
FIA_UID.1.2 The TSF shall require each user to be successfully
identified before allowing any other TSF-mediated
actions on behalf of that user.
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Hierarchical to: No other components.
Dependencies: No dependencies.
Refinement: The TOE verifies the identification information of an administrator provided by the
environment (see OE.I&A) before any management function can be performed.
Application Note: The “user” in FIA_UID.1.2 is identical to the administrator defined in the external
entities definition in chap. 3.3.
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5.1.4 Security management (FMT)
5.1.4.1 FMT_MSA.1 Management of security attributes
FMT_MSA.1.1 The TSF shall enforce the [Packet Filter SFP] to restrict
the ability to [modify, [no other operations]] the security
attributes [network traffic filter rules and configuration
data] to [the role administrator].
Hierarchical to: No other components.
Dependencies: [FDP_ACC.1 Subset access control, or
FDP_IFC.1 Subset information flow control]
FMT_SMR.1 Security roles
FMT_SMF.1 Specification of Management
5.1.4.2 FMT_MSA.3 Static attribute initialization
FMT_MSA.3.1 The TSF shall enforce the [Packet Filter SFP] to
provide [restrictive] default values for security attributes
that are used to enforce the SFP.
FMT_MSA.3.2 The TSF shall allow the [no roles] to specify alternative
initial values to override the default values when an
object or information is created.
Hierarchical to: No other components.
Dependencies: FMT_MSA.1 Management of security attributes
FMT_SMR.1 Security roles
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5.1.4.3 FMT_SMF.1 Specification of management functions
FMT_SMF.1.1 The TSF shall be capable of performing the following
management functions: [
 Modification of network traffic filter rules,
 Modification of configuration data].
Hierarchical to: No other components.
Dependencies: No dependencies.
5.1.4.4 FMT_SMR.1 Security roles
FMT_SMR.1.1 The TSF shall maintain the roles [administrator].
FMT_SMR.1.2 The TSF shall be able to associate users with roles.
Hierarchical to: No other components.
Dependencies: FIA_UID.1 Timing of identification
5.2 Extended Components definition
No extended components are defined in this Security Target.
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5.3 Security assurance requirements for the TOE
The following table lists the chosen evaluation assurance components for the TOE.
Assurance Class Assurance Components
ADV ADV_ARC.1, ADV_FSP.4, ADV_IMP.1, ADV_TDS.3
AGD AGD_OPE.1, AGD_PRE.1
ALC ALC_CMC.4, ALC_CMS.4, ALC_DEL.1, ALC_DVS.1
ALC_FLR.2, ALC_LCD.1, ALC_TAT.1
ATE ATE_COV.2, ATE_DPT.1, ATE_FUN.1, ATE_IND.2
Table 11: Chosen Evaluation Assurance Requirements
These assurance components represent EAL 4 augmented by the component marked in bold text.
The complete text for these requirements can be found in [2].
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5.4 Security Requirements Rationale
5.4.1 TOE functional requirements rationale
O.FILTER
O.AUDIT
O.MANAGEMENT
FAU_GEN.1 X
FIA_UID.1 X
FDP_IFC.1 X
FDP_IFF.1 X
FMT_MSA.1 X
FMT_MSA.3 X
FMT_SMF.1 X
FMT_SMR.1 X
Table 12: Coverage of Security Objective for the TOE by SFR
The security objective O.FILTER is met by a combination of FDP_IFC.1, FDP_IFF.1 and FMT_MSA.3.
FDP_IFC.1 and FDP_IFF.1 describe the information flow controls and information flow control policy.
Together, the SFRs describe how the packet filter information flow policies apply. FMT_MSA.3 defines
that the TOE has to provide restrictive default values for the Packet Filter SFP (information flow policy)
attributes. The SFRs are therefore sufficient to satisfy the objective O.FILTER and mutually
supportive.
The security objective O.AUDIT is met by FAU_GEN.1. FAU_GEN.1 describes when and what kind of
audit data is generated.
The security objective O.MANAGEMENT is met by FMT_SMF.1, FMT_MSA.1, FIA_UID.1 and
FMT_SMR.1. FMT_SMF.1 describes the minimum set of management functionality, which has to be
available. FMT_MSA.1 defines, which roles are allowed to administer the security attributes of the
TOE. FIA_UID.1 requires each user to be identified before allowing any relevant actions on behalf of
that user. Further the objective requires that the TOE will at least maintain the role administrator. This
is defined in FMT_SMR.1, which defines the role.
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5.4.2 Fulfilling the SFR dependencies
The following table shows that all dependencies are met.
SFR Dependencies Fulfilled by
FAU_GEN.1 FPT_STM.1 FPT_STM.1 is satisfied in the IT
environment (see OE.TSP).
FIA_UID.1 No dependencies. -
FDP_IFC.1 FDP_IFF.1 FDP_IFF.1
FDP_IFF.1 FDP_IFC.1 FDP_IFC.1
FMT_MSA.3 FMT_MSA.3
FMT_MSA.1 [FDP_ACC.1or FDP_IFC.1] FDP_IFC.1
FMT_SMR.1 FMT_SMR.1
FMT_SMF.1 FMT_SMF.1
FMT_MSA.3 FMT_MSA.1 FMT_MSA.1
FMT_SMR.1 FMT_SMR.1
FMT_SMF.1 No dependencies. -
FMT_SMR.1 FIA_UID.1 FIA_UID.1
Table 13: Fulfilling the SFR dependencies
5.4.3 Security assurance requirements rationale
The TOE claims compliance to EAL4 level of assurance augmented by ALC_FLR.2. As described in
[2], the level EAL4 indicates that the product is methodically designed, tested, and reviewed.
The assurance requirements for life cycle support have been augmented by ALC_FLR.2 (flaw
reporting procedures) to account for regular bug fixes for the TOE.
This is considered appropriate for attackers with Enhanced-Basic attack potential. The Security
assurance requirements are chosen because of the evaluation level EAL4 according to [2].
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6 TOE SUMMARY SPECIFICATION
6.1 TOE security functionality
6.1.1 SF1 Information Flow Protection
SF1.1 meets FDP_IFC.1, SF1.1, SF1.2 and SF1.3 meet FDP_IFF.1:
SF1.1: The TSF implements the information flow control (as routers) on the network layer (IP) and
transport layer (TCP/UDP/ICMP). In order to define packet filter rules the TSF provides packet filter
criteria and packet filter actions. The packet filter criteria are:
 source address
 destination address
 transport layer protocol
 interface on which traffic arrives and departs
 port
 time
The packet filter actions are:
 accept (= permit)
 reject
1
(= deny)
 drop
In order to apply the packet filter rules the network components take the information from the IP and
TCP/UDP/ICMP-Header (where applicable).
SF1.2: The TSF reassembles IP datagrams before further processing is performed. IP datagrams
which cannot be reassembled in a predefined span of time are dropped.
SF1.3: The TSF drops packets with spoofed source- or destination-IP addresses. Packets with source
routing options are also dropped.
6.1.2 SF2 Security Audit
SF2.1 and SF2.2 meet FAU_GEN.1:
SF2.1: The TSF generates audit records for
 start-up and shutdown of the audit functions
 datagrams received or sent through a network components network interfaces if they match
configured patterns
1
: reject = drop and signal an error
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SF2.2: Each record includes:
 Time and Date
 Affected network component
 Subject identity (source IP)
 Type of event
 Affected Interface
 Direction
 Action (accept, drop or reject)
 Optional depending on the protocol: IP addresses and ports
6.1.3 SF3 Management
SF3.1 meets FMT_SMF.1. SF3.2 meets FIA_UID.1, FMT_MSA.1 and FMT_SMR.1. SF3.3 meets
FMT_MSA.3.
SF3.1: The TSF is capable of performing the following management functions:
 Modification of network traffic filter rules,
 Modification of configuration data,
SF3.2: In order to modify the security attributes network traffic filter rules and configuration data the
TOE maintains the role administrator. The TOE verifies the identification information of an
administrator provided by the environment (see OE.I&A) before any management function can be
performed. Therefore the TOE verifies if the user id is equal to zero.
SF3.3: The TOE is initialized with a strict packet filter rule set, i. e. everything is dropped.
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7 GLOSSARY AND ACRONYMS
Definition
AES Advanced Encryption Standard
BSI Bundesamt für Sicherheit in der Informationstechnik
LAN Local Area Network
NTP Network Time Protocol
PP Protection Profile
SFP Security Function Policy
SFR Security Functional Requirement
SSH Secure Shell
ST Security Target
TOE Target of Evaluation
TSF TOE Security Function
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8 REFERENCES
Common Criteria
[1] Common Criteria for Information 2: Security Functional Components; Version 3.1, Revision 4,
CCMB-2012-09-002
[2] Common Criteria for Information Technology Security Evaluation, Part 3: Security Assurance
Components; Version 3.1, Revision 4, CCMB-2012-09-003
Cryptography
[3] RFC4253, SSH Transport Layer Protocol, http://www.ietf.org/rfc/rfc4253.txt
[4] RFC 791, Internet Protocol, http://www.ietf.org/rfc/rfc791.txt
Documentation
[5] secunet wall packet filter, documentation