ETSI TR 187 002 V2.1.1 (2008-12)

Technical Report
Telecommunications and Internet converged Services and
Protocols for Advanced Networking (TISPAN);
TISPAN NGN Security (NGN_SEC);
Threat, Vulnerability and Risk Analysis

2 ETSI TR 187 002 V2.1.1 (2008-12)

Reference
RTR/TISPAN-07030-NGN-R2
Keywords
analysis, security
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ETSI
3 ETSI TR 187 002 V2.1.1 (2008-12)
Contents
Intellectual Property Rights . 7
Foreword . 7
1 Scope . 8
2 References . 8
2.1 Normative references . 8
2.2 Informative references . 9
3 Definitions and abbreviations . 11
3.1 Definitions . 11
3.2 Abbreviations . 12
4 NGN-relevant Security Interfaces and Scenarios . 13
4.1 Security-relevant NGN Scenarios . 13
4.1.1 Basic NGN scenario (ECN&S model) . 14
4.1.2 IMS scenarios . 14
4.1.2.1 3GPP IMS . 14
4.1.2.2 Generic or NGN IMS . 15
4.1.3 Nomadic user security scenario . 17
5 Threat and risk analysis . 17
5.1 PES Analysis . 17
5.1.1 PES objectives and security objectives . 17
5.1.2 Stage 2 model of PES (UML) . 18
5.1.2.1 Identification of assets . 19
5.1.2.2 Missing considerations in PES . 19
5.1.2.2.1 ECN technology . 19
5.1.2.2.2 Protocol stack . 20
5.1.2.2.3 Cardinality of relationships . 20
5.1.2.2.4 Deployment . 20
5.1.3 Points of attack in PES. 20
5.1.3.1 Interfaces . 20
5.1.3.2 Implicit relationships . 20
5.1.4 Risk analysis . 21
5.1.4.1 Overview . 21
5.1.4.2 Interception . 21
5.1.4.2.1 Interception at the customer to MGW interface . 21
5.1.4.2.2 Interception within the fixed network . 21
5.1.4.3 Manipulation . 21
5.1.4.3.1 Manipulation at the customer interface . 22
5.1.4.3.2 Manipulation in the fixed parts of the network . 22
5.1.4.3.3 Manipulation in links between networks . 23
5.1.4.4 Denial-of-Service . 23
5.1.5 PES unwanted incidents . 24
5.1.6 Existing PES security provisions . 24
5.1.7 Security capabilities in PES . 24
5.1.7.1 H.248 ETSI_ARGW . 24
5.1.7.1.1 Authentication . 24
5.1.7.1.2 Confidentiality of signalling . 24
5.1.7.1.3 Confidentiality of traffic . 24
5.1.7.1.4 Integrity of signalling . 25
5.1.7.1.5 Integrity of traffic . 25
5.1.8 Role of NGN subsystems in PES . 25
5.1.8.1 Transport plane . 25
5.1.8.1.1 NASS . 25
5.1.8.1.2 RACS . 25
5.1.8.1.3 Transport elements . 25
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4 ETSI TR 187 002 V2.1.1 (2008-12)
5.1.8.2 Service plane . 25
5.1.8.2.1 IMS . 25
5.1.8.2.2 PSS . 25
5.1.8.3 Recommendations . 25
5.2 Analysis of NASS . 26
5.2.1 NASS-IMS bundled authentication analysis . 26
5.2.1.1 NASS-IMS bundled Authentication objectives and security objectives . 26
5.2.1.2 Stage 2 model of NASS-IMS bundled authentication . 26
5.2.1.2.1 Identification of assets . 27
5.2.1.2.2 Missing considerations in NASS . 28
5.2.1.3 Points of attack on the NASS-IMS bundled authentication . 29
5.2.1.3.1 Interfaces . 29
5.2.1.4 Risk analysis . 29
5.2.1.4.1 Overview . 29
5.2.1.4.2 Interception . 29
5.2.1.4.3 Manipulation . 30
5.2.1.4.4 IP Address and Identity spoofing . 32
5.2.1.4.5 Invalidation of IP address not signalled . 33
5.2.1.4.6 Denial-of-Service . 33
5.2.1.4.7 "line-id poisoning" attack with malicious P-Access-Network-Info . 34
5.2.1.5 NASS-IMS bundled authentication related unwanted incidents . 35
5.3 Analysis of RACS . 35
5.4 Analysis of NGN-IMS . 35
5.5 Analysis of DNS and ENUM in NGN. 35
5.6 Analysis of SIP in NGN . 35
6 Conclusions for NGN-R1 . . 36
Annex A: TVRA of RACS in NGN-R2 . 39
A.1 Scope of the TVRA . 39
A.2 Identification of the ToE . 39
A.2.1 Overview . 39
A.2.2 Scenarios for analysis and derivation of ToE . 41
A.2.2.1 Summary . 41
A.2.2.2 Single trust domain deployment scenario . 41
A.2.2.3 Two separate trust domains deployment scenario . 42
A.2.2.4 Two collaborating trust domains deployment scenario. 43
A.2.2.5 Multi trust domain deployment scenarios . 44
A.3 Analysis of ToE elements. 45
A.3.1 Transport processing functions . 45
A.3.2 SPDF . 46
A.3.3 46
A.3.4 Reference points . 46
A.3.5 Information flow analysis . 47
A.4 Security objectives . 51
A.5 Threats to RACS and threat agents to enable them . 52
A.6 Countermeasures for risk mitigation in RACS . 53
A.6.1 Functional requirements . 53
A.6.2 Detail requirements . 54
Annex B: TVRA of Media transport NGN-R2 . 55
B.1 Description of ToE . 55
B.2 Identification of objectives . 57
B.3 Step 2: Identification of requirements . 57
Annex C: Example TVRA for use of ENUM in NGN . 60
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5 ETSI TR 187 002 V2.1.1 (2008-12)
C.1 Overview and introduction . 60
C.1.1 Security critical ENUM operations . 62
C.1.1.1 Registration of an E.164 number in the ENUM database . 62
C.1.1.2 Processes for creation, modification and deletion of NAPTR Records in the Tier 2 database . 63
C.1.1.3 Processes for removal of E.164 numbers from ENUM databases . 64
C.1.1.4 Processes for changing Registrars . 65
C.1.2 ENUM assets . 66
C.1.2.1 NAPTR records . 66
C.1.2.2 ENUM query . 66
C.2 DNSSEC. 66
C.3 Unwanted incidents in use of ENUM in NGN (eTVRA Step 1) . 67
C.4 Security requirements for ENUM in the NGN (eTVRA Step 2) . 67
C.5 ENUM assets (eTVRA Step 3) . 69
C.5.1 NNA provisioning scenario . 69
C.5.2 Signalling scenario . 70
C.5.3 Identification of assets . 71
C.5.4 Logical Assets . 72
C.5.5 Physical Assets . 72
C.5.6 Summary of assets . 73
C.5.7 Relationships between assets . 74
C.6 Vulnerabilities in ENUM (eTVRA Step 4) . 75
C.6.1 Weakness in ENUM (eTVRA Step 4a) . 75
C.6.2 Threat agents in ENUM (eTVRA Step 4b) . 76
C.6.3 Identification of vulnerabilities in ENUM (eTVRA Step 4.1) . 77
C.7 Risk assessment for ENUM (eTVRA Step 5) . 78
C.8 ENUM risk classification (eTVRA Step 6) . 79
C.9 ENUM countermeasure framework (eTVRA Step 7) . 81
C.10 Completed eTVRA proforma for ENUM. 83
Annex D: TVRA of IPTV in NGN-R2 . 86
D.1 Step 0: Description of ToE (IPTV) . 86
D.1.1 IPTV stakeholders . 86
D.2 Step 1: Identification of objectives . 88
D.2.2 (System) Security Objectives . 88
D.2.2.1 Security objective category authentication . 88
D.2.2.2 Security objective category accountability . 89
D.2.2.3 Security objective category confidentiality . 89
D.2.2.4 Security objective category integrity . 89
D.2.2.5 Security objective category availability . 89
D.3 Step 2: Identification of requirements . 89
D.3.1 Security requirements category authentication . 89
D.3.2 Security requirement category accountability . 90
D.3.3 Security requirement category confidentiality. 91
D.3.4 Security requirement category integrity . 92
D.3.5 Security requirement category availability: . 92
D.4 Step 3: Inventory of the assets . 93
Annex E: TVRA of NAT and NAT-T in NGN-R2 . 94
E.1 Step 0: Description of NAT and NAT-T in NGN-R2 . 94
E.2 Step 1: Identification of objectives . 96
E.2.1 (System) Security Objectives . 96
E.3 Step 2: Identification of requirements . 97
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6 ETSI TR 187 002 V2.1.1 (2008-12)
E.4 Step 3: Inventory of the assets . 100
E.5 Vulnerabilities in R2 NAT traversal (eTVRA Step 4) . 101
E.5.1 Weakness in R2 NAT traversal (eTVRA Step 4a) . 101
E.5.2 Threat agents in R2 NAT traversal (eTVRA Step 4b). 101
E.6 Threats to NAT-T and threat agents to enable them (TVRA steps 4 and 5) . 102
E.6.1 Identification of threats and threat agents in STUN . 102
E.6.1.1 Manipulation threats and threat agents . 102
E.6.1.1.1 Attacker in NAT-T path . 102
E.6.1.1.1.1 Interception of STUN messages. . 102
E.6.1.1.1.2 Manipulation of STUN messages. . 102
E.6.1.1.1.3 Construction of integrity check value . 103
E.6.1.1.1.4 Manipulation of STUN protocol . 103
E.6.1.1.2 Attacker in NAT-T endpoint . 104
E.6.1.2 STUN usage attacks . 104
E.6.1.2.1 DDoS Against a Target . 104
E.6.1.2.2 Silencing a Client . 104
E.6.1.2.3 Masquerade as a known Client . 104
E.6.1.2.4 Eavesdropping . 104
E.6.1.2.5 Risk analysis for use of ICE . 105
E.6.1.2.6 Risk analysis for use of Outbound . 105
E.6.2 Risk analysis for use of IMS-ALG . 105
Annex F: TVRA of UC in NGN-R2 . . 106
Annex G: Change history . 107
History . 108

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7 ETSI TR 187 002 V2.1.1 (2008-12)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Telecommunications and Internet
converged Services and Protocols for Advanced Networking (TISPAN).
ETSI
8 ETSI TR 187 002 V2.1.1 (2008-12)
1 Scope
The present document presents the results of the Threat Vulnerability Risk Analysis (TVRA) for the NGN.
The present document follows the method and proforma for carrying out a TVRA defined in TS 102 165-1 [i.4] and
incorporates material of the NGN threat and risk analysis herein.
The present document identifies security-relevant interfaces in the NGN, identifies security-relevant scenarios for use in
the NGN, analyses NGN in terms of security threats and risks by performing a security threat and risk analysis, and
classifies the identified vulnerabilities and the associated risk presented to the NGN.
This threat and risk analysis makes a number of assumptions that are believed to hold for typical deployment scenarios
of the NGN.
NOTE 1: Depending on the actual instantiation of the NGN some of the assumptions declared in the present
document may not fully hold and this may alter the associated risks.
NOTE 2: Whilst the present document is a technical report it identifies requirements for future work. In all cases
these requirements are considered indicative pending their ratification in formal ETSI Technical
Specifications within the TISPAN Work Programme.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
• if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
• for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
For online referenced documents, information sufficient to identify and locate the source shall be provided. Preferably,
the primary source of the referenced document should be cited, in order to ensure traceability. Furthermore, the
reference should, as far as possible, remain valid for the expected life of the document. The reference shall include the
method of access to the referenced document and the full network address, with the same punctuation and use of upper
case and lower case letters.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
Not applicable.
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9 ETSI TR 187 002 V2.1.1 (2008-12)
2.2 Informative references
The following referenced documents are not essential to the use of the ETSI deliverable but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] ETSI EG 202 387: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Security Design Guide; Method for application of Common
Criteria to ETSI deliverables".
[i.2] ETSI TS 181 005: "Telecommunications and Internet Converged Services and Protocols for
Advanced Networking (TISPAN); Service and Capability Requirements".
[i.3] ISO/IEC 13335: "Information technology - Guidelines for the management of IT security".
[i.4] ETSI TS 102 165-1, (V4.2.1): "Telecommunications and Internet converged Services and
Protocols for Advanced Networking (TISPAN); Methods and protocols; Part 1: Method and
proforma for Threat, Risk, Vulnerability Analysis".
[i.5] ETSI ES 282 004: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Functional Architecture; Network Attachment
Sub-System (NASS)".
[i.6] ETSI TS 187 001: "Telecommunications and Internet Converged Services and Protocols for
Advanced Networking (TISPAN); NGN SECurity (SEC); Requirements".
[i.7] ETSI TS 187 003: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Security; Security Architecture".
[i.8] ETSI TR 180 001: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Release 1; Release definition".
[i.9] ETSI ES 282 002: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); PSTN/ISDN Emulation Sub-system (PES); Functional
architecture".
[i.10] ETSI ES 282 003: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Resource and Admission Control Sub-System (RACS):
Functional Architecture".
[i.11] ETSI ES 283 002: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); PSTN/ISDN Emulation Subsystem (PES); NGN Release 1
H.248 Profile for controlling Access and Residential Gateways".
[i.12] ETSI EN 383 001: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Interworking between Session Initiation Protocol (SIP) and
Bearer Independent Call Control (BICC) Protocol or ISDN User Part (ISUP)
[ITU-T Recommendation Q.1912.5, modified]".
[i.13] ETSI TS 133 210: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); 3G security; Network Domain Security (NDS); IP network
layer security (3GPP TS 33.210 Release 7)".
[i.14] AS/NZS 4360: "Risk Management".
[i.15] Directive 2002/21/EC of the European Parliament and of the council of 7 March 2002 on a
common regulatory framework for electronic communications networks and services (Framework
Directive).
[i.16] Directive 2002/58/EC of the European Parliament and of the council of 12 July 2002 concerning
the processing of personal data and the protection of privacy in the electronic communications
sector (Directive on privacy and electronic communications).
[i.17] ETSI ES 282 001: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Functional Architecture Release 1".
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10 ETSI TR 187 002 V2.1.1 (2008-12)
[i.18] IETF RFC 3261: "SIP: Session Initiation Protocol".
[i.19] ETSI TS 133 203: "Digital cellular telecommunications system (Phase 2+); Universal Mobile
Telecommunications System (UMTS); 3G security; Access security for IP-based services
(3GPP TS 33.203 Release 7)".
[i.20] ETSI TS 133 234: "Universal Mobile Telecommunications System (UMTS); 3G security;
Wireless Local Area Network (WLAN) interworking security (3GPP TS 33.234 Release 6)".
[i.21] ITU-T Recommendation H.248: "Gateway control protocol".
[i.22] ETSI TR 102 055: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); ENUM scenarios for user and infrastructure ENUM".
[i.23] ETSI TR 102 420: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Review of activity on security".
[i.24] IETF RFC 2535: "Domain Name System Security Extensions".
[i.25] IETF RFC 3761: "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation
Discovery System (DDDS) Application (ENUM)".
[i.26] IETF RFC 3403: "Dynamic Delegation Discovery System (DDDS) Part Three: The Domain Name
System (DNS) Database".
[i.27] IETF RFC 2915: "The Naming Authority Pointer (NAPTR) DNS Resource Record".
[i.28] Draft-ietf-dnsext-dnssec-protocol-06 (2004): "Protocol Modifications for the DNS Security
Extensions".
[i.29] Draft-ietf-dnsext-dnssec-records-08 (2004): "Resource Records for DNS Security Extensions".
[i.30] Draft-ietf-dnsext-dnssec-intro-11 (2004): "DNS Security Introduction and Requirements".
[i.31] ISO/IEC 15408-2: "Information technology - Security techniques - Evaluation criteria for IT
security - Part 2: Security functional requirements".
[i.32] ISO/IEC 15408: "Information technology - Security techniques - Evaluation criteria for IT
security".
NOTE: When referring to all parts of ISO/IEC 15408 the reference above is used.
[i.33] 3GPP TR 33.803: "3rd Generation Partnership Project; Technical Specification Group Services
and System Aspects; Coexistence between TISPAN and 3GPP authentication schemes
(Release 7)".
[i.34] ETSI TR 187 011: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); NGN Security; Application of ISO-15408-2 requirements to
ETSI standards - guide, method and application with examples".
[i.35] ETSI TS 183 017: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Resource and Admission Control: DIAMETER protocol for
session based policy set-up information exchange between the Application Function (AF) and the
Service Policy Decision Function (SPDF); Protocol Specification".
[i.36] IETF RFC 1631: "The IP Network Address Translator (NAT)".
[i.37] IETF RFC 1918: "Address Allocation for Private Internets".
[i.38] IETF RFC 3489: "STUN - Simple Traversal of User Datagram Protocol (UDP) Through Network
Address Translators (NATs)".
[i.39] IETF draft, draft-ietf-behave-rfc3489bis-13 (November 2007): "STUN - Simple Traversal of User
Datagram Protocol (UDP) Through Network Address Translators (NATs)".
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11 ETSI TR 187 002 V2.1.1 (2008-12)
[i.40] IETF draft, draft-ietf-mmusic-ice-19 (October 2007): "Interactive Connectivity Establishment
(ICE): A Methodology for Network Address Translator (NAT) Traversal for Offer/Answer
Protocols".
[i.41] IETF draft, draft-behave-turn-02 (February 2006): "Obtaining Relay Addresses from Simple
Traversal of UDP Through NAT (STUN)".
[i.42] ETSI TR 187 009: "Telecommunications and Internet Converged Services and Protocols for
Advanced Networking (TISPAN); Feasibility study of prevention of unsolicited communication in
the NGN".
[i.43] ETSI SR 002 211: "Electronic communications networks and services; Candidate list of standards
and/or specifications in accordance with Article 17 of Directive 2002/21/EC".
[i.44] ETSI TS 181 016: "Telecommunications and Internet converged Services and Protocols for
Advanced Networking (TISPAN); Service Layer Requirements to integrate NGN services and
IPTV".
[i.45] Directive 95/46/EC Of The European Parliament And Of The Council of 24 October 1995 on the
protection of individuals with regard to the processing of personal data and on the free movement
of such data.
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in EG 202 387 [i.1] and the following apply:
attack: attempt to bypass security controls on a computer
NAT traversal: term used to describe the problem of establishing connections between hosts in IP networks which use
NAT devices (either locally or remotely) to modify their local IP address
Network Address Translation: method by which IP addresses are mapped from one realm to another in order to
provide transparent routing to hosts
NOTE: NAT devices are used to connect address domains with private (unregistered) addresses to public
domains with globally unique (registered) addresses.
T-nnn: numeric identifier for a threat
threat: potential cause of an unwanted incident which may result in harm to a system or organization
NOTE: See ISO/IEC 13335 [i.3].
unwanted incident: incident such as loss of confidentiality, integrity and/or availability
NOTE: See AS/NZS 4360 [i.14].
vulnerability: flaw or weakness in system security procedures, system design, implementation, internal controls, etc.,
that could be exploited to violate system security policy
NOTE: Vulnerability is often used synonymously with weakness.
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12 ETSI TR 187 002 V2.1.1 (2008-12)
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
rd
3G 3 Generation
rd
3GPP 3 Generation Partnership Project
AF Application Function
AGCF Access Gateway Control Function
AGW Access GateWay
AH Authentication Header
A-MGF Access Media Gateway Function
A-RACF Access-Resource and Admission Control Function
ARGW Access Residential media GateWay
AS Application Server
BGF Border Gateway Function
BTF Basic Transport Function
CC Call Control
CD Compact Disc
CHAP Challenge Handshake Authentication Protocol
CLF Connectivity session and repository Location Function
CPE Customer Premises Equipment
C-RACF Core-Resource and Admission Control Function
CSCF Call Session Control Function
DNS Domain Name System
DNSSEC DNS SECurity
DoS Denial-of-Service
DTMF Dual Tone Multi Frequency
EAP Extensible Authentication Protocol
ECN Electronic Communication Network
ECN&S Electronic Communications Networks and Services
ECS Electronic Communication Service
ESP Encapsulating Security Payload
FFS For Further Study
FQDN Fully Qualified Domain Name
GPRS GSM Packet Radio System
ICE Interactive Connectivity Establishment
I-CSCF Interrogating Call Session Control Function
IETF Internet Engineering Task Force
IKE Internet Key Exchange
IMS IP Multimedia Subsystem
IMSI IMS subscriber Identifier
IP Internet Protocol
IPsec Internet Protocol security
IPTV Internet Protocol TeleVision
ISDN Integrated Services Digital Network
ISIM IMS Subscriber Identity Module
ISO International Standards Organization
ISUP ISDN User Part
IVR Interactive Voice Response
MAC Message Authentica
...