SIST-TS TS 102 165-1 V4.1.1:2004
(Main)Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 4; Protocol Framework Definition; Methods and Protocols for Security; Part 1: Threat Analysis
- Abstract
The present document defines by means of an information model, a functional entity behavioural model, and by validated SDL a model of the abstract behaviour of each service and service capability identified as being essential in TIPHON R4. This part derives, by means of a threat analysis, the requirements for security features that when implemented are necessary and sufficient to ensure that TIPHON derived products do no harm to their participants.
- Status
- Published
- Publication Date
- 31-Mar-2004
- Technical Committee
- SPN - Services and Protocols for Networks
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 01-Apr-2004
- Due Date
- 01-Apr-2004
- Completion Date
- 01-Apr-2004
SIST-TS TS 102 165-1 V4.1.1:2004 is the Slovenian version of ETSI TS 102 165-1 V4.1.1 for Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 4. Published by SIST, it is Part 1: Threat Analysis for the TIPHON security framework. It defines the threat model and the security feature requirements needed for TIPHON services, terminals, operators, and service providers.
What does SIST-TS TS 102 165-1 V4.1.1:2004 specify?
SIST-TS TS 102 165-1 V4.1.1:2004 specifies the TIPHON Release 4 security threat analysis and the resulting security requirements. It uses an information model, a functional entity behavioural model, and validated SDL to describe the abstract behaviour of essential TIPHON services and service capabilities.
The standard is organized as a framework document followed by a detailed threat analysis and security requirements section, with informative annexes for SIP and H.323-specific analysis.
| Annex | What it covers |
|---|---|
| Annex A | SIP specific threat analysis |
| Annex B | ITU-T H.323 specific threat analysis |
| Annex C | Bibliography |
The foreword also identifies this document as Part 1 of a multi-part deliverable, with Part 2 covering countermeasures.
What are the key requirements of SIST-TS TS 102 165-1 V4.1.1:2004?
SIST-TS TS 102 165-1 V4.1.1:2004 turns threat analysis into named security services and policy requirements. In practice, it tells a designer which links, identities, and procedures need protection, and why those protections matter.
Security objectives and legal context
Clause 5 says TIPHON security must protect user-related information and the resources of serving and home functional groups from misuse or misappropriation. It also calls for worldwide availability, worldwide interoperability, and the ability to extend the security design as new threats appear.
Clause 6 adds legal constraints. Privacy laws affect what personal data can be collected, stored, processed, and shown; security-order laws may restrict cryptography; lawful interception affects confidentiality; and contract information may need to stand up in court. For implementers, this means security design is not only technical - it also has to fit national law and operator policy.
Threat model and exposed links
Clause 7 treats several links as vulnerable: user to SpoA, user to Registrar, registrar to SpoAs in different domains, service-domain links, service-to-transport links, and transport-domain links. It also states that the user should be able to check network authentication, meaning the serving network must be authorized by the home network and the authorization must be recent.
This matters because the standard assumes attackers can target attachment, signaling, registration, and inter-domain communication. Protection therefore has to cover the access side, the registration side, and the network-to-network side.
Risk assessment method
Clause 8 analyzes intentional non-physical threats only. It classifies threats such as masquerade, unauthorized access, eavesdropping, loss or corruption of information, repudiation, forgery, and denial of service.
Risk is calculated from two 1-to-3 ratings: occurrence likelihood and impact. The result is then grouped as minor, major, or critical risk. The document says threats with risk 4 or higher need countermeasures, and risk 6 or 9 threats get highest priority. For a reader choosing controls, this means the standard is not just descriptive - it gives a way to rank what must be addressed first.
Main security services and policy controls
Clause 9 defines the security services and policy measures used to counter the identified risks:
- Authentication (A1-A7) - terminal, registrar, SpoA, and user authentication.
- Access control (C1-C5) - control of services, data, terminal data, software, and hardware.
- Confidentiality (E1-E7) - protection of user communication, signaling, TIPHON-id, and inter-domain traffic.
- Integrity (I1-I2) - signaling integrity and bulk data transfer integrity.
- General security policy (P1-P10) - billing limits, secure billing administration, subscriber and terminal management, user reports, operator dialogue, contractual arrangements, and secure subscription.
Clause 9.6 then selects an initial set of these measures to cover all risk-9 threats and many risk-6 threats. In practice, if you are specifying a TIPHON-related system, these are the controls to check first for registration, call setup, service profile handling, and billing-related security.
Cryptographic and terminal considerations
Clause 4 says cryptographic countermeasures may use symmetric keying or asymmetric keying, and both should be supported where cryptography is needed. Clause 4.5 also points to a future TIPHON terminal form based on a Secure Signature Creation Device (SSCD), which is relevant where strong authorization and authentication are tied to electronic signatures.
What terms does SIST-TS TS 102 165-1 V4.1.1:2004 define?
- TIPHON-id - The identifier used for a TIPHON user, and a central privacy and masquerade target in the threat analysis.
- Service point of Attachment (SpoA) - The serving network group where the user connects, acting as a service-domain and transport-domain attachment point.
- Transport point of Attachement (TpoA) - The transport-side attachment point used when describing communication protection across domains.
- Security domain - A set of entities and parties governed by one security policy and one security administration.
- Trusted Third Party (TTP) - A party that may be needed to support trust-related security functions between other actors.
- Secure Signature Creation Device (SSCD) - A future terminal form considered for authorization and authentication in the context of advanced electronic signatures.
- Lawful Interception (LI) - The operator obligation to cooperate and provide information for criminal investigations.
Who uses SIST-TS TS 102 165-1 V4.1.1:2004?
The standard is used by TIPHON network operators, service providers, terminal and software vendors, and security architects working on VoIP or packet-based telephony services. It is also relevant to subscribers, service customers, and end users because it maps threats to controls that affect registration, call handling, privacy, and billing.
In practice, these roles use it to design authentication, access control, confidentiality, billing protection, terminal management, and inter-operator security procedures.
Which standards are used with SIST-TS TS 102 165-1 V4.1.1:2004?
- TR 101 877 and TS 101 878 - provide the TIPHON simple-call requirements and service-capability terms used for definitions.
- TS 101 314 and TS 101 303 - provide TIPHON architecture, reference points, and management framework context.
- TS 102 165-2 - the companion Part 2 that defines countermeasures.
- TS 101 331 - gives the Lawful Interception requirements referenced in the security discussion.
- ETR 336 - provides security standardization background for telecommunications management.
- RFC 3261, H.323, Q.1902, RFC 1889, RFC 2326, RFC 3015, RFC 2327 - give the SIP, multimedia, call control, RTP, RTSP, Megaco, and SDP protocol context used in the annexes and threat discussion.
- Directive 1999/93/EC - provides the electronic-signature framework referenced for SSCD considerations.
What does the SIST-TS TS 102 165-1 V4.1.1:2004 document contain?
The document contains a structured threat catalogue, risk tables, and a mapping from threats to security services and policy measures. Clause 8 lists threats for general operation, registration, incoming and outgoing calls, emergency calls, and service-profile handling, then scores them by likelihood and impact.
Clause 9 maps those threats to named services such as authentication, access control, confidentiality, integrity, and policy controls. Annex A repeats the analysis for SIP, including SIP methods, responses, and protocol components. Annex B does the same for ITU-T H.323 and its annex J security profile, including SASET and hybrid security mechanisms.
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Frequently Asked Questions
SIST-TS TS 102 165-1 V4.1.1:2004 is a technical specification published by the Slovenian Institute for Standardization (SIST). Its full title is "Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 4; Protocol Framework Definition; Methods and Protocols for Security; Part 1: Threat Analysis". This standard covers: The present document defines by means of an information model, a functional entity behavioural model, and by validated SDL a model of the abstract behaviour of each service and service capability identified as being essential in TIPHON R4. This part derives, by means of a threat analysis, the requirements for security features that when implemented are necessary and sufficient to ensure that TIPHON derived products do no harm to their participants.
The present document defines by means of an information model, a functional entity behavioural model, and by validated SDL a model of the abstract behaviour of each service and service capability identified as being essential in TIPHON R4. This part derives, by means of a threat analysis, the requirements for security features that when implemented are necessary and sufficient to ensure that TIPHON derived products do no harm to their participants.
SIST-TS TS 102 165-1 V4.1.1:2004 is classified under the following ICS (International Classification for Standards) categories: 33.020 - Telecommunications in general. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST-TS TS 102 165-1 V4.1.1:2004 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2004
Harmonizacija telekomunikacij in internetnega protokola prek omrežij (TIPHON), 4.
izdaja - Definicija okvira protokola - Varnostne metode in protokoli - 1. del: Analiza
groženj
Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON)
Release 4; Protocol Framework Definition; Methods and Protocols for Security; Part 1:
Threat Analysis
Ta slovenski standard je istoveten z: TS 102 165-1 Version 4.1.1
ICS:
33.020 Telekomunikacije na splošno Telecommunications in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
Technical Specification
Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON) Release 4;
Protocol Framework Definition;
Methods and Protocols for Security;
Part 1: Threat Analysis
2 ETSI TS 102 165-1 V4.1.1 (2003-02)
Reference
DTS/TIPHON-08005-1R4
Keywords
IP, protocol, security, VoIP
ETSI
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The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2003.
All rights reserved.
TM TM TM
DECT , PLUGTESTS and UMTS are Trade Marks of ETSI registered for the benefit of its Members.
TM
TIPHON and the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members.
TM
3GPP is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners.
ETSI
3 ETSI TS 102 165-1 V4.1.1 (2003-02)
Contents
Intellectual Property Rights.6
Foreword.6
1 Scope.7
2 References.7
3 Definitions and abbreviations.8
3.1 Definitions.8
3.2 Abbreviations.8
4 TIPHON overview.8
4.1 Introduction.8
4.2 Architecture.9
4.2.1 Specific meta-protocols.9
4.2.2 Specific implementations.9
4.3 Forms of implementation .10
4.3.1 Terminal types.10
4.4 Cryptographic countermeasures.10
4.5 Future TIPHON terminal.11
5 Security objectives.11
6 Legislation issues.12
6.1 Privacy.12
6.2 Security order.12
6.3 Lawful Interception (LI).12
6.4 Contract.13
7 Security framework.13
7.1 General assumptions.13
7.2 Capabilities in framework .13
7.2.1 Network access security.13
7.2.1.1 User identity confidentiality.13
7.2.1.2 Entity authentication.13
7.2.1.3 Confidentiality.14
7.2.2 Security visibility and configurability .14
7.2.2.1 Visibility.14
7.2.2.2 Configurability.14
8 Threat analysis and risk assessment .15
8.1 Threats.15
8.2 Actors and roles.16
8.3 Security domains.16
8.4 Description of threats .16
8.4.1 General threats.16
8.4.1.1 Eavesdropping of TIPHON-id on interfaces or entities .16
8.4.1.2 Getting the TIPHON-id from a terminal .16
8.4.1.3 Denial of service.17
8.4.1.4 Unauthorized access to data .17
8.4.1.5 Flooding the network .17
8.4.1.6 Stolen terminals.17
8.4.1.7 Subscription fraud.17
8.4.1.8 Unauthorized access to data in terminals .18
8.4.1.9 Masquerading as one network entity to an other one .18
8.4.2 Threats related to data deletion procedures.18
8.4.2.1 Eavesdropping of old address .18
8.4.2.2 Masquerading as a network entity to delete data.18
8.4.3 Threats related to subscription registration procedures.18
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4 ETSI TS 102 165-1 V4.1.1 (2003-02)
8.4.3.1 Illegal registration by an attacker masquerading as service provider.18
8.4.4 Threats related to subscription de-registration procedures .19
8.4.4.1 Illegal de-registration by an attacker masquerading as service provider.19
8.4.4.2 Subscriber does not allow de-registration by manipulating his terminal.19
8.4.4.3 Subscriber does not allow de-registration by manipulating the signalling interface .19
8.4.5 Threats related to incoming call procedures .19
8.4.5.1 Masquerading by using someone's TIPHON-id.19
8.4.5.2 Masquerading by using someone's TIPHON-id and authentication information.20
8.4.5.3 Eavesdropping of the communication on the access interface by use of the session key .20
8.4.5.4 Eavesdropping of the start of a communication on the access interface .20
8.4.5.5 Eavesdropping of roaming number or routing number .20
8.4.5.6 Modification of routing data .20
8.4.6 Threats related to outgoing call procedures .20
8.4.6.1 Masquerading by using someone's TIPHON-id.20
8.4.6.2 Masquerading by using someone's TIPHON-id and authentication information.21
8.4.6.3 Eavesdropping of the communication on the access interface by use of the session key .21
8.4.6.4 Eavesdropping of the communication on the NNI interfaces.21
8.4.6.5 Eavesdropping of the start of a communication on the access interface .21
8.4.6.6 Eavesdropping of the phone number of the called party.21
8.4.6.7 Modification of the dialled number.21
8.4.6.8 Masquerading by using someone's TIPHON-id only.21
8.4.7 Threats related to emergency call procedures.21
8.4.7.1 Misuse of emergency call.21
8.4.7.2 Manipulate data to give an emergency number to somebody .22
8.4.8 Threats related to service profile.22
8.4.8.1 Eavesdropping of transmitted information during service profile transfer.22
8.4.8.2 Manipulation of transmitted information during service profile transfer.22
8.4.8.3 Unauthorized access to the service profile of somebody by unauthorized use of service profile
interrogation .22
8.4.8.4 Unauthorized access to, or unauthorized use of, the service profile modification procedure .22
8.5 Tabulated summary of threats .23
8.6 Risk Measurement.24
8.7 Risk Assessment for the TIPHON network procedures .25
8.8 Consolidated Risk Assessment.29
8.9 Conclusion.29
9 TIPHON security requirements and security services.31
9.1 Authentication.32
9.1.1 A1 = Authentication of the terminal by the registrar (home of the user profile) .32
9.1.2 A2 = Authentication of the registrar by the terminal .32
9.1.3 A3 = Authentication of the terminal by the Service point of Attachment (SpoA).32
9.1.4 A4 = Authentication of the SpoA by the terminal .32
9.1.5 A5 = Authentication of the SpoA by the registrar .32
9.1.6 A6 = Authentication of the registrar by the SpoA .32
9.1.7 A7 = Authentication of the user to the TIPHON terminal device.32
9.2 Access control.32
9.2.1 C1 = Access control to services.32
9.2.2 C2 = Access control to data .33
9.2.3 C3 = Access control to data in terminal.33
9.2.4 C4 = Access control to software .33
9.2.5 C5 = Access control to hardware.33
9.3 Confidentiality.33
9.3.1 E1 = Confidentiality of user communication on the access interface .33
9.3.2 E2 = Confidentiality of signalling on the access interface.33
9.3.3 E3 = Confidentiality of signalling between SpoA entities.33
9.3.4 E4 = Confidentiality of signalling between SpoA and TpoA .34
9.3.5 E5 = Confidentiality of communication between TpoAs.34
9.3.6 E6 = Confidentiality of TIPHON-id on signalling interfaces .34
9.3.7 E7 = Confidentiality of communication between SpoA and Registrar (registration services).34
9.4 Integrity.34
9.4.1 I1 = Signalling data integrity .34
9.4.2 I2 = Bulk data transfer data integrity .34
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5 ETSI TS 102 165-1 V4.1.1 (2003-02)
9.5 General security policy.34
9.5.1 P1 = Bill limitations.34
9.5.2 P2 = Secure billing administration.35
9.5.3 P3 = Subscriber and terminal management.35
9.5.4 P4 = Hotline.35
9.5.5 P5 = Security related reports to the user .35
9.5.6 P6 = Secure dialogue between operators .36
9.5.7 P7 = Contractual agreements between operators .36
9.5.8 P8 = Contractual agreements between service providers and subscribers .36
9.5.9 P9 = Security related reports to the service provider .37
9.5.10 P10 = Secure subscription process.37
9.6 Threats and counteracting security measures .37
Annex A (informative): SIP specific threat analysis.40
A.1 Introduction.40
A.2 Extract from RFC 3261 .40
A.3 SIP protocol, methods and responses.41
A.3.1 Protocol.41
A.3.2 Methods.41
A.3.2.1 Security concerns of SIP methods .41
A.3.3 Protocol components.41
A.4 The threats and risk factors .42
Annex B (informative): ITU-T H.323 specific threat analysis.46
B.1 Introduction.46
B.2 Extract from H.323 (November 2000) .46
B.3 Discussion.46
B.4 Extract from H.323 annex J.47
B.4.1 Secure Audio Simple Endpoint Type (SASET) .47
B.4.1.1 Assumptions.47
B.4.1.2 Overview.47
B.4.3 Observations for TIPHON.48
B.5 The threats and risk factors .49
Annex C (informative): Bibliography.53
History .54
ETSI
6 ETSI TS 102 165-1 V4.1.1 (2003-02)
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).
All published ETSI deliverables shall include information which directs the reader to the above source of information.
Foreword
This Technical Specification (TS) has been produced by ETSI Project Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON).
The present document is part 1 of a multi-part deliverable covering Methods and Protocols for security in TIPHON
Release 4, as identified below:
Part 1: "Threat Analysis";
Part 2: "Counter Measures".
ETSI
7 ETSI TS 102 165-1 V4.1.1 (2003-02)
1 Scope
The present document defines by means of an information model, a functional entity behavioural model, and by
validated SDL a model of the abstract behaviour of each service and service capability identified as being essential in
TIPHON R4.
This part derives, by means of a threat analysis, the requirements for security features that when implemented are
necessary and sufficient to ensure that TIPHON derived products do no harm to their participants.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• 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.
• For a non-specific reference, the latest version applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
[1] Void.
[2] ETSI TR 101 877: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Requirements Definition Study; Scope and Requirements for a Simple call".
[3] ETSI TS 101 878: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Service Capability Definition; Service Capabilities for a simple call".
[4] Directive 1999/93/EC of the European Parliament and of the Council of 13 December 1999 on a
Community framework for electronic signatures.
[5] ETSI TS 101 331: "Telecommunications security; Lawful Interception (LI); Requirements of Law
Enforcement Agencies".
[6] ETSI ETR 336: "Telecommunications Management Network (TMN); Introduction to
standardizing security for TMN".
[7] ETSI TS 101 314: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Abstract Architecture and Reference Points Definition; Network
Architecture and Reference Points".
[8] ETSI TS 101 303: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 4; Service Independent Requirements Definition; Service and Network
Management Framework; Part 1: Overview and Introduction".
[9] ETSI TS 102 165-2: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 4; Protocol Framework Definition; Methods and Protocols for Security;
Part 2: Counter Measures".
[10] IETF RFC 3261: "SIP: Session Initiation Protocol ".
[11] ITU-T Recommendation H.323: "Packet-based multimedia communications systems".
[12] ITU-T Recommendation Q.1902 (1 to 6): "Bearer Independent Call Control protocol (Capability
Set 2)".
[13] ETSI EN 300 347-1: "V interfaces at the digital Local Exchange (LE); V5.2 interface for the
support of Access Network (AN); Part 1: V5.2 interface specification".
ETSI
8 ETSI TS 102 165-1 V4.1.1 (2003-02)
[14] IETF RFC 1889: "RTP: A Transport Protocol for Real-Time Applications".
[15] IETF RFC 2326: "Real Time Streaming Protocol (RTSP)".
[16] IETF RFC 3015: "Megaco Protocol Version 1.0".
[17] IETF RFC 2327: "SDP: Session Description Protocol".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 101 877 [2] and TS 101 878 [3] apply.
3.2 Abbreviations
For the purposes of the present document, the abbreviations defined in TR 101 877 [2], TS 101 878 [3] and the
following apply:
ATM Asynchronous Transfer Mode
BICC Bearer Independent Call Control
FDDI Fibre Distributed Data Interface
GK GateKeeper
GSTN General Switched Talaphone Network
ISDN Integrated Service Digital Network
LI Lawful Interception
MEGACO Media Gateway Control Protocol
NNI Network to Network Interface
PBN Packet Based Network
PSTN Public Switched Telephone Network
QoS Quality of Service
RPC Remote Procedure Call
RTP Real-time Transport Protocol
RTSP Real Time Streaming Protocol
SASET Secure Audio Simple Endpoint Type
SDP Session Description Protocol
SET Simple Endpoint Types
SIP Session Initiation Protocol
SpoA Service point of Attachment
SSCD Secure Signature Creation Device
TpoA Transport point of Attachement
TTP Trusted Third Party
UAC User Agent Client
UAS User Agent Server
4 TIPHON overview
4.1 Introduction
TIPHON acts in the first instance as an umbrella set of service and service capability specifications defined in the form
of a meta-protocol (see TS 101 882-1), and secondly as a set of protocol implementation mappings to the meta-protocol.
In this respect there is no single protocol or service that has to be protected by counter measures within TIPHON.
Furthermore the conventions of a threat analysis most often consider an implemented product (or protocol in TIPHON
terms) and rarely deal with the purely abstract environment considered in TIPHON's meta-protocol.
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9 ETSI TS 102 165-1 V4.1.1 (2003-02)
4.2 Architecture
The TIPHON architecture shown in simplified form in figure 1 is formed from functional entities co-operating to
provide capabilities which are then added to form services.
Home
SP
SpoA IVN SpoA
Terminal Terminal
TpoA (SP + TP) TpoA
Figure 1: Simplified TIPHON interconnection architecture
In summary in TIPHON a Terminal is connected to a Serving network group that acts as both Service point of
Attachment and as Transport point of Attachment (i.e. offers both service domain and transport domain). The serving
network group is also connected to the Home Service Provider of the User and this acts as registrar and initial route for
incoming calls. Between the originating and terminating domain may be one or more intervening domains containing
both Service and Transport sub-domains.
The UNI interfaces have a scope of a single user. The Network to Network Interface (NNI) interfaces have a scope of
many users.
Two forms of domain are considered in TIPHON: The Service Domain and the Transport Domain. The NNI signalling
for a single service within the Service Domain may carry with it an association of many supporting services offered by
the Transport Domain.
4.2.1 Specific meta-protocols
Each meta-protocol is described in terms of essential functional element and by identification of the information
elements that need to be transferred between functional elements to facilitate operation. Threat analysis and
countermeasures are in the first instance applied to the meta-protocol.
4.2.2 Specific implementations
Implementations that conform to the TIPHON meta-protocols are described for a number of protocol families and will
include but not be restricted to:
SIP [10];
H.323 [11] (including H.225.0, H.245, H.248);
BICC [12]; and
V5.2 [13].
Where countermeasures exist in the meta-protocols to which a mapping is made then it is expected that a provision in
the mapping for a specific protocol's implementation will also include provision of the countermeasures.
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10 ETSI TS 102 165-1 V4.1.1 (2003-02)
4.3 Forms of implementation
TIPHON, in achieving the goal of an umbrella specification, allows many forms of implementation. Each form of
implementation will address a common set of threats, and will also address a technology specific set of threats. One of
the goals of the present document (and its partner Countermeasures document) is to develop as large as possible the set
of common threats and to therefore provide as large a set as possible of common countermeasures.
4.3.1 Terminal types
The user terminal for TIPHON services within the umbrella will fall within a continuum of implementations from
hardware without built-in intelligence, to a wholly software platform with advanced intelligence. Examples are given in
the following lists:
VoIP terminal types:
Personal computer + SIP SW client;
Personal computer + H.323 SW client;
SIP HW telephone;
H.323 HW telephone.
VoSCN terminal types:
PSTN phone;
ISDN phone;
GSM terminal;
3G/UMTS terminal.
Hybrid terminal environments:
PSTN/ISDN terminals connected directly to the PSTN/ISDN network;
PSTN/ISDN terminals connected to an adapter for SIP telephony; and
PSTN/ISDN terminals connected to an adapter for H.323 telephony.
4.4 Cryptographic countermeasures
Countermeasures to security threats do not need to be made cryptographic. In many cases countermeasures cannot be
applied that employ cryptography. However where cryptographic countermeasures are employed they use essentially
one of two (2) keying stratagems:
Symmetric keying
Parties have access to the same key and generally only two parties are involved.
Asymmetric keying
Each party has a two part key, one part is public and available to all correspondents, one part is private
and known to only one party (the key owner). Security is derived from the premise that it is
mathematically difficult (assumed impossible in current technology) to derive the private part from
knowledge of the public part.
These keying mechanisms are generally bound to an identity and used to provide authenticity of the source, with the
possibility to use the same keying stratagem for provision of confidentiality of transmitted content and for determining
the integrity of transmitted content. Where the parties are known to one another in advance symmetric keying methods
are traditionally favoured, and where the parties are unknown to one another in advance asymmetric methods are
commonly employed.
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Within the framework of TIPHON where a threat needs to be countered by the provision of cryptographic
countermeasures both stratagems of keying should be supported.
4.5 Future TIPHON terminal
The constraints applied to future TIPHON terminals need to be considered.
The Directive 1999/93/EC of the European Parliament and of the Council of 13 December 1999 on a Community
framework for electronic signatures [4] quoted in the Official Journal L 013, 19/01/2000 P. 0012 - 0020 says:
QUOTE: Advanced electronic signatures which are based on a qualified certificate and which are created by
a secure-signature-creation device can be regarded as legally equivalent to hand-written signatures.
This may suggest that future TIPHON terminals take the form of a Secure Signature Creation Device (SSCD) and that
standardizations must advance to a stage that a card can be inserted into any SSCD to enable authorization and
authentication to services.
5 Security objectives
TIPHON™ shall meet the following objectives:
a) to ensure that information generated by or relating to a user is adequately protected against misuse or
misappropriation;
b) to ensure that the resources and services provided by serving and home functional groups are adequately
protected against misuse or misappropriation;
c) to ensure that the security features standardized are compatible with world-wide availability (i.e. there should
be at least one ciphering algorithm that can be exported on a world-wide basis (in accordance with the
Wassenaar agreement, see bibliography);
d) to ensure that the security features are adequately standardized to ensure world-wide interoperability between
different serving functional groups;
e) to ensure that the implementation of security features and mechanisms can be extended and enhanced as
required by new threats and services.
The basic security features employed in existing fixed and mobile systems will be retained, or where needed, enhanced.
These include:
- subscriber authentication,
- encryption,
- subscriber identity confidentiality,
- use of removable subscriber module,
- secure application layer channel between subscriber module and home network,
- transparency of security features,
- minimized need for trust between home and serving functional groups.
The above objectives together can be met by provision of methods to achieve the following goals:
• confidentiality
The avoidance of the disclosure of information without the permission of its owner.
• integrity
The property that data has not been altered or destroyed in an unauthorized manner.
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• accountability
The principle whereby individuals are held responsible for the effect of any of their actions that might lead to a
violation.
• availability
The property of being accessible and usable upon demand by an authorized entity.
• non-repudiation
A property by which one of the entities or parties in a communication cannot deny having participated in the
whole or part of the communication.
6 Legislation issues
The following areas of legislation may have influence on the realization of security.
6.1 Privacy
Privacy legislation is of increasing importance; there are strong restrictions in many countries with regard to storage and
visibility of data. Therefore, when offering a service within TIPHON, or when designing data processing functions and
defining the kind of data being generated or stored within TIPHON systems, TIPHON service providers shall consider
the relevant national data protection laws.
The definition of privacy includes:
- privacy of information: keeping information exchanged between service functions away from third parties;
- limitations on collection, storage and processing of personal data: personal data may only be collected, stored
and processed if there is a relationship between the data and the actual provision of services;
- disclosure: the obligation of a network and service providers to keep information concerning customers away
from third parties;
- inspection and correction: the right of the customer to inspect and correct information about himself stored by
the service and/or network provider.
Privacy legislation will mostly concern the security objectives regarding "data confidentiality" and "data integrity". For
TIPHON special concern in this respect shall be paid to the contents of personal data in the TIPHON service profile.
These data and the access conditions to it for the service provider's personnel, the subscriber and the user himself shall
be limited, in accordance with the relevant European guidelines and national laws.
6.2 Security order
National laws concerning the security order:
- demand proper protection of information and infrastructure to ensure the availability and the integrity of the
telecommunication network;
- may restrict the usage of cryptographic methods.
This legislation will mostly concern the security objectives regarding "data confidentiality", "data integrity" and
"availability".
6.3 Lawful Interception (LI)
Lawful Interception means the obligation of the network operator to co-operate and provide information in case of
criminal investigations (see e.g. TS 101 331 [5]).
This legislation will mostly influence the security objectives regarding "data confidentiality".
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6.4 Contract
It shall be possible to use information concerning the contract for communication services between two entities in case
of a dispute in a court of law.
This legislation will mostly influence the security objectives regarding "accountability" and "data integrity".
7 Security framework
7.1 General assumptions
The following general assumptions are made for the provision of security functions in TIPHON:
• The user to SpoA link is vulnerable;
• The user to Registrar link is vulnerable;
• Links from SpoA to other network resident entities in the same network are not vulnerable;
• Links from the registrar to SpoAs in different networks/domains are vulnerable;
• Links between service domains are vulnerable;
• Links between service domains and transport domains are vulnerable; and
• Links between transport domains are vulnerable.
7.2 Capabilities in framework
7.2.1 Network access security
7.2.1.1 User identity confidentiality
The following security features related to user identity confidentiality should be provided:
- user identity confidentiality: the property that the permanent user identity of a user to whom a service is
delivered cannot be eavesdropped on the access link;
- user location confidentiality: the property that the presence or the arrival of a user in a certain area cannot be
determined by eavesdropping on the access link;
- user untraceability: the property that an intruder cannot deduce whether different services are delivered to the
same user by eavesdropping on the access link.
To achieve these objectives, the user should normally be identified by a temporary identity by which he is known by the
visited (serving) network. To avoid user traceability, which may lead to the compromise of user identity confidentiality,
the user should not be identified for a long period by means of the same temporary identity. To achieve these security
features, in addition it is required that any signalling or user data that might reveal the user's true identity is protected
(enciphered) on the access link.
7.2.1.2 Entity authentication
The following security features related to entity authentication should be provided:
- user authentication: the property that the serving network corroborates the identity of the user;
- network entity authentication: the property that the serving network corroborates the identity of entities that
operate within the network;
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- network authentication: the property that the user corroborates that he is connected to a serving network that
is authorized by the user's home to provide him services; this includes the guarantee that this authorization is
recent.
7.2.1.3 Confidentiality
The following security features with respect to confidentiality of data on the access link (terminal to SpoA
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