draft-ietf-dime-e2e-sec-req-02.txt   draft-ietf-dime-e2e-sec-req-03.txt 
DIME H. Tschofenig DIME H. Tschofenig
Internet-Draft Internet-Draft ARM Limited
Intended status: Informational J. Korhonen Intended status: Informational J. Korhonen, Ed.
Expires: July 30, 2015 Broadcom Expires: December 19, 2015 Broadcom Corporation
G. Zorn G. Zorn
Network Zen Network Zen
K. Pillay K. Pillay
Oracle Communications Oracle Communications
January 26, 2015 June 17, 2015
Diameter AVP Level Security End-to-End Security: Scenarios and Diameter AVP Level Security End-to-End Security: Scenarios and
Requirements Requirements
draft-ietf-dime-e2e-sec-req-02.txt draft-ietf-dime-e2e-sec-req-03.txt
Abstract Abstract
This specification discusses requirements for providing Diameter This specification discusses requirements for providing Diameter
security at the level of individual Attribute Value Pairs. security at the level of individual Attribute Value Pairs.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 30, 2015. This Internet-Draft will expire on December 19, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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between neighboring Diameter peers and mandates that either TLS (for between neighboring Diameter peers and mandates that either TLS (for
TCP), DTLS (for SCTP), or IPsec is used. These security protocols TCP), DTLS (for SCTP), or IPsec is used. These security protocols
offer a wide range of security properties, including entity offer a wide range of security properties, including entity
authentication, data-origin authentication, integrity, authentication, data-origin authentication, integrity,
confidentiality protection and replay protection. They also support confidentiality protection and replay protection. They also support
a large number of cryptographic algorithms, algorithm negotiation, a large number of cryptographic algorithms, algorithm negotiation,
and different types of credentials. and different types of credentials.
The need to also offer additional security protection of AVPs between The need to also offer additional security protection of AVPs between
non-neighboring Diameter nodes was recognized very early in the work non-neighboring Diameter nodes was recognized very early in the work
on Diameter. This lead to work on Diameter security using the on Diameter. This led to work on Diameter security using the
Cryptographic Message Syntax (CMS) [3]. Due to lack of deployment Cryptographic Message Syntax (CMS) [3]. Due to lack of deployment
interest at that time (and the complexity of the developed solution) interest at that time (and the complexity of the developed solution)
the specification was, however, never completed. the specification was, however, never completed.
In the meanwhile Diameter had received a lot of deployment interest In the meanwhile Diameter had received a lot of deployment interest
from the cellular operator community and because of the from the cellular operator community and because of the
sophistication of those deployments the need for protecting Diameter sophistication of those deployments the need for protecting Diameter
AVPs between non-neighboring nodes re-surfaced. Since early 2000 AVPs between non-neighboring nodes re-surfaced. Since early 2000
(when the work on [3] was discontinued) the Internet community had (when the work on [3] was discontinued) the Internet community had
seen advances in cryptographic algorithms (for example, authenticated seen advances in cryptographic algorithms (for example, authenticated
encryption algorithms) and new security building blocks were encryption algorithms) and new security building blocks were
developed. developed.
This document collects requirements for developing a solution to This document collects requirements for developing a solution to
protect Diameter AVPs. protect Diameter AVPs.
2. Terminology 2. Terminology
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this
specification are to be interpreted as described in [1]. documents are to be interpreted as described in RFC 2119 [1].
This document re-uses terminology from the Diameter base This document re-uses terminology from the Diameter base
specification [2]. specification [2].
In the figures below we use the symbols 'AVP' and '{AVP}k'. AVP In the figures below we use the symbols 'AVP' and '{AVP}k'. AVP
refers to an unprotected AVP and {AVP}k refers to an AVP that refers to an unprotected AVP and {AVP}k refers to an AVP that
experiences security protection (using key "k") without further experiences security protection (using key "k") without further
distinguishing between integrity and confidentiality protection. distinguishing between integrity and confidentiality protection.
3. Security Threats 3. Security Threats
The follow description aims to illustrate various security threats The following description aims to illustrate various security threats
that raise the need for protecting Diameter Attribute Value Pairs that raise the need for protecting Diameter Attribute Value Pairs
(AVPs). Figure 1 illustrates an example Diameter topology where a (AVPs). Figure 1 illustrates an example Diameter topology where a
Diameter clients want to interact with the example.com home domain. Diameter clients want to interact with the example.com home domain.
To interconnect the two visited networks a AAA interconnection To interconnect the two visited networks a AAA interconnection
provider, labeled as AAA Broker, is used. provider, labeled as AAA Broker, is used.
+oooooooooooooooooo+ +====================+ +oooooooooooooooooo+ +====================+
| Example.net | | | | Example.net | | |
| | | | | | | |
+--------+ +--------+ +--------+ +--------+ +--------+ +--------+ +--------+ +--------+
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To detect such actions additional security protection needs to be To detect such actions additional security protection needs to be
applied at the Diameter layer. applied at the Diameter layer.
Nodes that could launch such an attack are any Diameter agents Nodes that could launch such an attack are any Diameter agents
along the end-to-end communication path. along the end-to-end communication path.
Impersonation: Imagine a case where a Diameter message from Impersonation: Imagine a case where a Diameter message from
Example.net contains information claiming to be from Example.org. Example.net contains information claiming to be from Example.org.
This would either require strict verification at the edge of the This would either require strict verification at the edge of the
AAA broker network or cryptographic assurance at the Diameter AAA broker network or cryptographic assurance at the Diameter
layer to provent a successful impersonation attack. layer to prevent a successful impersonation attack.
Any Diameter realm could launch such an attack aiming for Any Diameter realm could launch such an attack aiming for
financial benefits or to disrupt service availability. financial benefits or to disrupt service availability.
4. Scenarios for Diameter AVP-Level Protection 4. Scenarios for Diameter AVP-Level Protection
This scenario outlines a number of cases for deploying security This scenario outlines a number of cases for deploying security
protection of individual Diameter AVPs. protection of individual Diameter AVPs.
In the first scenario, shown in Figure 2, end-to-end security In the first scenario, shown in Figure 2, end-to-end security
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security protection for individual Diameter AVPs. Without protection security protection for individual Diameter AVPs. Without protection
there is the possibility for password sniffing, confidentiality there is the possibility for password sniffing, confidentiality
violation, AVP insertion, deletion or modification. Additionally, violation, AVP insertion, deletion or modification. Additionally,
applying digital signature offers non-repudiation capabilities; a applying digital signature offers non-repudiation capabilities; a
feature not yet available in today's Diameter deployment. feature not yet available in today's Diameter deployment.
Modification of certain Diameter AVPs may not necessarily be the act Modification of certain Diameter AVPs may not necessarily be the act
of malicious behavior but could also be the result of of malicious behavior but could also be the result of
misconfiguration. An over-aggressively configured firewalling misconfiguration. An over-aggressively configured firewalling
Diameter proxy may also remove certain AVPs. In most cases data Diameter proxy may also remove certain AVPs. In most cases data
origin authentication and integrity protection of AVPs will provide origin authentication and integrity protection of AVPs will provide
most benefits for existing deployments with minimal overhead and the most benefits for existing deployments with minimal overhead and
(potentially) operating in a full-backwards compatible manner. (potentially) operating in a full-backwards compatible manner.
5. Requirements 5. Requirements
Requirement #1: Solutions MUST support an extensible set of Requirement #1: Solutions MUST support an extensible set of
cryptographic algorithms. cryptographic algorithms.
Motivation: Crypto-agility is the ability of a protocol to Motivation: Solutions MUST be able to evolve to adapt to
adapt to evolving cryptographic algorithms and security evolving cryptographic algorithms and security requirements.
requirements. This may include the provision of a modular This may include the provision of a modular mechanism to allow
mechanism to allow cryptographic algorithms to be updated cryptographic algorithms to be updated without substantial
without substantial disruption to deployed implementations. disruption to deployed implementations.
Requirement #2: Solutions MUST support confidentiality, integrity, Requirement #2: Solutions MUST support confidentiality, integrity,
and data-origin authentication. Solutions for integrity and data-origin authentication. Solutions for integrity
protection MUST work in a backwards-compatible way with existing protection MUST work in a backwards-compatible way with existing
Diameter applications. Diameter applications.
Requirement #3: Solutions MUST support replay protection. Any Requirement #3: Solutions MUST support replay protection. All
Diameter node has an access to network time and thus can Diameter nodes have access to network time and thus can
synchronise their clocks. synchronize their clocks.
Requirement #4: Solutions MUST support the ability to delegate Requirement #4: Solutions MUST support the ability to delegate
security functionality to another entity security functionality to another entity
Motivation: As described in Section 4 the ability to let a Motivation: As described in Section 4 the ability to let a
Diameter proxy to perform security services on behalf of all Diameter proxy to perform security services on behalf of all
clients within the same administrative domain is important for clients within the same administrative domain is important for
incremental deployability. The same applies to the other incremental deployability. The same applies to the other
communication side where a load balancer terminates security communication side where a load balancer terminates security
services for the servers it interfaces. services for the servers it interfaces.
Requirement #5: Solutions MUST be able to selectively apply their Requirement #5: Solutions MUST be able to selectively apply their
cryptographic protection to certain Diameter AVPs. cryptographic protection to certain Diameter AVPs.
Motivation: Some Diameter applications assume that certain AVPs Motivation: Some Diameter applications assume that certain AVPs
are added, removed, or modified by intermediaries. As such, it are added, removed, or modified by intermediaries. As such, it
MUST be possible to apply security protection selectively. MUST be possible to apply security protection selectively.
Furthermore, there are AVPs that MUST NOT be confidentiality
protected but MAY still be integrity protected such as those
required for Diameter message routing.
Requirement #6: Solutions MUST recommend a mandatory-to-implement Requirement #6: Solutions MUST recommend a mandatory-to-implement
cryptographic algorithm. cryptographic algorithm.
Motivation: For interoperability purposes it is beneficial to Motivation: For interoperability purposes it is beneficial to
have a mandatory-to-implement cryptographic algorithm specified have a mandatory-to-implement cryptographic algorithm specified
(unless profiles for specific usage environments specify (unless profiles for specific usage environments specify
otherwise). otherwise).
Requirement #7: Solutions MUST support symmetric keys and asymmetric Requirement #7: Solutions MUST support symmetric keys and asymmetric
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This entire document focused on the discussion of new functionality This entire document focused on the discussion of new functionality
for securing Diameter AVPs selectively between non-neighboring nodes. for securing Diameter AVPs selectively between non-neighboring nodes.
7. IANA Considerations 7. IANA Considerations
This document does not require actions by IANA. This document does not require actions by IANA.
8. Acknowledgments 8. Acknowledgments
We would like to thank Guenther Horn, Martin Dolly, for his review We would like to thank Guenther Horn, Martin Dolly, Steve Donovan and
comments. Tom Taylor for their review comments.
9. References 9. References
9.1. Normative References 9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate [1] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[2] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn, [2] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
"Diameter Base Protocol", RFC 6733, October 2012. "Diameter Base Protocol", RFC 6733, October 2012.
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Security Application", draft-ietf-aaa-diameter-cms-sec-04 Security Application", draft-ietf-aaa-diameter-cms-sec-04
(work in progress), March 2002. (work in progress), March 2002.
[4] Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible [4] Eronen, P., Hiller, T., and G. Zorn, "Diameter Extensible
Authentication Protocol (EAP) Application", RFC 4072, Authentication Protocol (EAP) Application", RFC 4072,
August 2005. August 2005.
Authors' Addresses Authors' Addresses
Hannes Tschofenig Hannes Tschofenig
Hall in Tirol 6060 ARM Limited
Austria Austria
Email: Hannes.tschofenig@gmx.net Email: Hannes.tschofenig@gmx.net
URI: http://www.tschofenig.priv.at URI: http://www.tschofenig.priv.at
Jouni Korhonen Jouni Korhonen (editor)
Broadcom Broadcom Corporation
Porkkalankatu 24 3151 Zanker Rd.
Helsinki 00180 San Jose, CA 95134
Finland USA
Email: jouni.nospam@gmail.com Email: jouni.nospam@gmail.com
Glen Zorn Glen Zorn
Network Zen Network Zen
227/358 Thanon Sanphawut 227/358 Thanon Sanphawut
Bang Na Bangkok 10260 Bang Na Bangkok 10260
Thailand Thailand
Email: glenzorn@gmail.com Email: glenzorn@gmail.com
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