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.
	skipping to change at page 1, line 37		skipping to change at page 1, line 37
	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.
	skipping to change at page 9, line 8		skipping to change at page 9, line 8
	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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