< draft-froment-sipping-spit-requirements-00.txt		draft-froment-sipping-spit-requirements-01.txt >
	SIPPING H. Tschofenig, Ed.		SIPPING H. Tschofenig, Ed.
	Internet-Draft Nokia Siemens Networks		Internet-Draft Nokia Siemens Networks
	Intended status: Informational G. Dawirs		Intended status: Informational G. Dawirs
	Expires: December 16, 2007 University of Namur		Expires: January 10, 2008 University of Namur
	T. Froment		T. Froment
	Alcatel-Lucent		Alcatel-Lucent
	D. Wing		D. Wing
	Cisco		Cisco
	H. Schulzrinne		H. Schulzrinne
	Columbia University		Columbia University
	June 14, 2007		July 9, 2007
	Requirements for Authorization Policies to tackle Spam for Internet		Requirements for Authorization Policies to tackle Spam and Unwanted
	Telephony and Unwanted Traffic		Communication for Internet Telephony
	draft-froment-sipping-spit-requirements-00.txt		draft-froment-sipping-spit-requirements-01.txt
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 42 ¶		skipping to change at page 1, line 42 ¶
	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."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	This Internet-Draft will expire on December 16, 2007.		This Internet-Draft will expire on January 10, 2008.
	Copyright Notice		Copyright Notice
	Copyright (C) The IETF Trust (2007).		Copyright (C) The IETF Trust (2007).
	Abstract		Abstract
	Spam over Internet Telephony (SPIT) is one of the foreseen future		Spam over Internet Telephony (SPIT) is one of the foreseen future
	forms of spamming that SIP open-wide networks may have to handle.		forms of spamming that SIP open-wide networks may have to handle.
	SPIT also has more impact on users than email spam since it is more		SPIT also has more impact on users than email spam since it is more
	skipping to change at page 3, line 14 ¶		skipping to change at page 3, line 14 ¶
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
	3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 6		3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 6
	3.1. Conditions . . . . . . . . . . . . . . . . . . . . . . . . 6		3.1. Conditions . . . . . . . . . . . . . . . . . . . . . . . . 6
	3.2. Actions . . . . . . . . . . . . . . . . . . . . . . . . . 7		3.2. Actions . . . . . . . . . . . . . . . . . . . . . . . . . 7
	3.3. Transformations . . . . . . . . . . . . . . . . . . . . . 8		3.3. Transformations . . . . . . . . . . . . . . . . . . . . . 8
	3.4. Generic Requirements . . . . . . . . . . . . . . . . . . . 8		3.4. Generic Requirements . . . . . . . . . . . . . . . . . . . 8
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 11		5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12		6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13		7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	7.1. Normative References . . . . . . . . . . . . . . . . . . . 13		7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
	7.2. References . . . . . . . . . . . . . . . . . . . . . . . . 13		7.2. References . . . . . . . . . . . . . . . . . . . . . . . . 12
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
	Intellectual Property and Copyright Statements . . . . . . . . . . 17		Intellectual Property and Copyright Statements . . . . . . . . . . 15
	1. Introduction		1. Introduction
	The problem of SPIT is an important challenge and it appears that a		The problem of SPIT is an important challenge and it appears that a
	combination of several techniques is desirable to provide a framework		combination of several techniques is desirable to provide a framework
	to deal with it.		to deal with it.
	One important building block is to provide a mechanism to instruct a		One important building block is to provide a mechanism to instruct a
	trusted SIP proxy or any other SIP element to influence message		trusted SIP proxy or any other SIP element to influence message
	handling of incoming requests according to policies. Different		handling of incoming requests according to policies. Different
	skipping to change at page 5, line 14 ¶		skipping to change at page 6, line 5 ¶
	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
	document are to be interpreted as described in RFC 2119 [RFC2119],		document are to be interpreted as described in RFC 2119 [RFC2119],
	with the important qualification that, unless otherwise stated, these		with the important qualification that, unless otherwise stated, these
	terms apply to the design of the authorization policies, not its		terms apply to the design of the authorization policies, not its
	implementation or application.		implementation or application.
	The term 'Rule Maker' is defined in RFC 3693 [RFC3693].
	3. Requirements		3. Requirements
	This section lists the requirements categorized according to their		This section lists the requirements categorized according to their
	applicability for the "conditions", "actions" and "transformation"		applicability for the "conditions", "actions" and "transformation"
	parts of authorization policies. Furthermore, we describe		parts typically found in authorization policies.
	requirements that are more generic in nature and apply to the entire
	rule set.
	3.1. Conditions		3.1. Conditions
	The first set of requirements refer to identity related information.		The first set of requirements refer to identity related information.
	Req-C 1: Policies MUST allow conditions to express single		Req-C 1: Policies MUST allow conditions to express single
	authenticated identities.		authenticated identities.
	Req-C 2: Policies MUST allow filtering based on the domain part of		Req-C 2: Policies MUST allow filtering based on the domain part of
	the identity.		the identity.
	Req-C 3: Policies MUST support the differentiation between		Req-C 3: Policies MUST support the differentiation between
	authenticated and unauthenticated identities.		authenticated and unauthenticated identities.
	Req-C 4: Policies MUST be able to express expections within a group		Req-C 4: Policies MUST be able to express exceptions within a group
	of users/domain.		of users or a domain.
			Req-C 5: Policies SHOULD allow an anonymous identity as a condition.
	Message handling might be different depending on the content of the		Message handling might be different depending on the content of the
	SIP message header fields.		SIP message header fields.
	Req-C 5: Policies SHOULD allow conditions to refer to the		Req-C 6: Policies SHOULD allow conditions to refer to the
	"destination" (which corresponds to the "Request-URI") and		"destination" (which corresponds to the "Request-URI") and
	"original-destination" (which corresponds to the "To" header).		"original-destination" (which corresponds to the "To" header).
	Req-C 6: Policies SHOULD allow conditions to refer to the method		Req-C 7: Policies SHOULD allow conditions to refer to the method
	invoked by the caller (e.g., INVITE, REFER, MESSAGE).		invoked by the caller (e.g., INVITE, REFER, MESSAGE).
	Motivation: Some SIP methods are more intrusive than others		Motivation: Some SIP methods are more intrusive than others
	(the default applicative behaviour when SIP MESSAGEs are		(the default applicative behaviour when SIP MESSAGEs are
	received is often to pop-up the message on the UAS side),		received is often to pop-up the message on the UAS side),
	adopting a different filtering policy depending of the method		adopting a different filtering policy depending of the method
	invoked will enhance the user's protection.		invoked will enhance the user's protection.
	Req-C 7: Policies SHOULD allow Rule Makers to take actions on		Req-C 8: Policies SHOULD allow the entity that writes the rules to
	messages that are marked as Spam.		take actions on messages that are marked as Spam.
	Note that such a condition element should be seen in		Note that such a condition element should be seen in
	context of the authenticated domain or or otherwise		context of the authenticated domain or or otherwise
	protected information to avoid security		protected information to avoid security
	vulnerabilities.		vulnerabilities.
	[Editor's Note: Should we allow message handling based on the		Req-C 9: Policies MAY allow to make decisions based on the current
	existence or non-existence of certain SDP / SIP content, such as		state of the user. E.g., based on a user selected active
	specific mime types? For example, is a "exists" test useful that		profile, or sphere or other presence information.
	returns true if the headers listed in the argument exist within the
	message. Furthermore, do we need test operators (such as "allof" and		Req-C 10: Policies SHOULD support consitions based on the content
	"anyof", which implement logical "and" and logical "or",		type and/or offered (or used) media of a message.
	respectively)?
	Message handling might be different based on time.		Message handling might be different based on time.
	Req-C 7: Policies SHOULD allow conditions that refer to the		Req-C 11: Policies SHOULD allow conditions that refer to the
	reception date, time or period of time of the incoming		reception date, time, timezone or period of time of the
	request.		incoming request.
	Message handling might be different based on the language.		Message handling might be different based on the language.
	Req-C 8: Policies SHOULD allow to make decisions based on the		Req-C 12: Policies SHOULD allow to make decisions based on the
	languages in which the originator of the call wishes to		languages in which the originator of the call wishes to
	communicate.		communicate.
	Message handling might be different based on the SIP resource
	priority fields, on emergency service related messages or more
	generic forms of indicating the type of service.
	Req-C 9: Policies MAY allow to make decisions based on the presence
	of SIP Resouce Priority headers, as described in [RFC4412].
	Req-C 10: Policies SHOULD allow to make decisions based on the
	messages marked as emergency calls indicated in
	[I-D.ietf-ecrit-service-urn].
	Req-C 11: Policies MAY allow to make decisions based on service
	identification fields, see
	[I-D.rosenberg-sipping-service-identification].
	3.2. Actions		3.2. Actions
	Req-A 1: Policies SHOULD allow messages to get "blocked", i.e., to		Req-A 1: Policies SHOULD allow messages to get "blocked", i.e., to
	stop forwarding the request and to return an answer with a		stop forwarding the request and to return an answer with a
	``403 Forbidden''		``403 Forbidden''
	Req-A 2: Policies SHOULD allow messages to get "politely blocked",		Req-A 2: Policies SHOULD allow messages to get "politely blocked",
	i.e., to drop the request without returning an answer.		i.e., to drop the request without returning an answer.
	Req-A 2: Policies SHOULD allow messages to get "marked", i.e., to		Req-A 3: Policies SHOULD allow messages to get "marked", i.e., to
	forward the request and mark it as "potential Spam" for		forward the request and mark it as "potential Spam" for
	filtering at the end point or at subsequent entities along the		filtering at the end point or at subsequent entities along the
	signaling path.		signaling path.
	Req-A 3: Policies SHOULD allow messages to be "allowed", i.e., to		Req-A 4: Policies SHOULD allow messages to be "allowed", i.e., to
	forward this message.		forward this message.
	Req-A 4: Policies MUST allow messages to be "redirected" to, for		Req-A 5: Policies MUST allow messages to be "redirected" to, for
	example, voicemail or to a different device in the possession		example, voicemail or to a different device in the possession
	of the user.		of the user.
	Req-A 5: Policies MUST allow the ability to execute other SPIT		Req-A 6: Policies MUST allow executing other SPIT prevention
	prevention procedures, such as computational puzzles		procedures, such as computational puzzles
	[I-D.jennings-sip-hashcash] or the consent framework"		[I-D.jennings-sip-hashcash] or the consent framework"
	[I-D.ietf-sip-consent-framework]. Ideally, a specification		[I-D.ietf-sip-consent-framework]. A specification developing
	developing a SPIT prevention mechanism SHOULD provide		a SPIT prevention mechanism should provide information on how
	information on how they can be incorporated into the		they can be incorporated into the authorization policy
	authorization policy framework.		framework.
	As an example, for a statistical analysis tool a URI is
	defined. The algorithms itself do not need to be
	standardized and hence the impact for authorization
	policies is mainly the ability to allow a Rule Maker to
	enable or to disable the usage of these statistical
	techniques for SPIT filtering and potentially to map
	the output of the analysis process to value range from
	0 (i.e., the message is not classified as Spam) and 100
	(i.e., the message was classified as as Spam). A Rule
	Maker may decide the appropriate action on the message
	depending on the determined SPIT probability.
	Req-A 6: Policies MAY allow an e-mail (or SMS, MMS) to be sent to		Req-A 7: Policies MAY allow an e-mail (or SMS, MMS) or other
	the user about the actions taken due to a specific call		notifications to be sent to the user about the actions taken
	attempt.		due to a specific call attempt.
	3.3. Transformations		3.3. Transformations
	Req-T 1: Policies SHOULD allow SIP messages to be marked with a		Req-T 1: Policies SHOULD allow SIP messages to be marked with a
	certain SPIT probability in case SPIT detection and policy		certain SPIT probability in case SPIT detection and policy
	enforcement is excecuted on different entities. For example,		enforcement is excecuted on different entities. For example,
	a network element might run a statistical SPIT detection tool		a network element might run a statistical SPIT detection tool
	but the authorization policies are executed on a different		but the authorization policies are executed on a different
	entity, such as the end host. Note that it needs to be		entity, such as the end host. Note that it needs to be
	ensured that an adversary is not able to set the SPIT		ensured that an adversary is not able to set the SPIT
	skipping to change at page 9, line 4 ¶		skipping to change at page 8, line 22 ¶
	certain SPIT probability in case SPIT detection and policy		certain SPIT probability in case SPIT detection and policy
	enforcement is excecuted on different entities. For example,		enforcement is excecuted on different entities. For example,
	a network element might run a statistical SPIT detection tool		a network element might run a statistical SPIT detection tool
	but the authorization policies are executed on a different		but the authorization policies are executed on a different
	entity, such as the end host. Note that it needs to be		entity, such as the end host. Note that it needs to be
	ensured that an adversary is not able to set the SPIT		ensured that an adversary is not able to set the SPIT
	probabity values since otherwise the authorization policies		probabity values since otherwise the authorization policies
	that rely on such information are misguided.		that rely on such information are misguided.
	3.4. Generic Requirements		3.4. Generic Requirements
	Req-G 1: It SHOULD be possible to allow a hierarchy of authorization		Req-G 1: It SHOULD be possible to allow a hierarchy of authorization
	policies to be used.		policies to be used.
			It is quite likely that a rules from different rule writing
			entities are provided. For example, in a company environment
			policies from the system administrator are provided in
			addition to the end users policies. The former might reflect
			the overall company policy. The impact for the policy is
			mainly on the definition of an appropriate conflict resolution
			mechanism.
	Req-G 2: It MUST be possible for a client to learn the supported		Req-G 2: It MUST be possible for a client to learn the supported
	authorization policy capabilities implemented by the server.		authorization policy capabilities implemented by the server.
	Req-G 3: Policies MUST be extensible and these extensions MUST exist		Req-G 3: Policies MUST be extensible and these extensions MUST exist
	within a different namespace. Furthermore, a published schema		within a different namespace. Furthermore, a published schema
	and the namespace for elements defined within it MUST NOT be		and the namespace for elements defined within it MUST NOT be
	altered by future specifications.		altered by future specifications.
	Req-G 4: The policies MUST provide a mandatory-to-implement conflict		Req-G 4: The policies MUST provide a mandatory-to-implement conflict
	resolution mechanism.		resolution mechanism.
	skipping to change at page 13, line 5 ¶		skipping to change at page 11, line 12 ¶
	consequence with impact for more than a single end point. These		consequence with impact for more than a single end point. These
	security aspects are, however, not subject of this document.		security aspects are, however, not subject of this document.
	6. Acknowledgements		6. Acknowledgements
	The content of this document is inspired by the work of CPL		The content of this document is inspired by the work of CPL
	[RFC3880], SIEVE [I-D.ietf-sieve-3028bis], Common Policy [RFC4745]		[RFC3880], SIEVE [I-D.ietf-sieve-3028bis], Common Policy [RFC4745]
	and Presence Authorization Policy [I-D.ietf-simple-presence-rules].		and Presence Authorization Policy [I-D.ietf-simple-presence-rules].
	We would like to thank the authors of these documents for their work.		We would like to thank the authors of these documents for their work.
			Furthermore, we would like to thank Eva Leppanen for the detailed
			review provided in June 2006.
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] 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.
	7.2. References		7.2. References
	[I-D.ietf-ecrit-service-urn]
	Schulzrinne, H., "A Uniform Resource Name (URN) for
	Services", draft-ietf-ecrit-service-urn-06 (work in
	progress), March 2007.
	[I-D.ietf-sieve-3028bis]		[I-D.ietf-sieve-3028bis]
	Showalter, T. and P. Guenther, "Sieve: An Email Filtering		Showalter, T. and P. Guenther, "Sieve: An Email Filtering
	Language", draft-ietf-sieve-3028bis-12 (work in progress),		Language", draft-ietf-sieve-3028bis-12 (work in progress),
	February 2007.		February 2007.
	[I-D.ietf-simple-presence-rules]		[I-D.ietf-simple-presence-rules]
	Rosenberg, J., "Presence Authorization Rules",		Rosenberg, J., "Presence Authorization Rules",
	draft-ietf-simple-presence-rules-09 (work in progress),		draft-ietf-simple-presence-rules-10 (work in progress),
	March 2007.		July 2007.
	[I-D.ietf-sip-consent-framework]		[I-D.ietf-sip-consent-framework]
	Rosenberg, J., "A Framework for Consent-Based		Rosenberg, J., "A Framework for Consent-Based
	Communications in the Session Initiation Protocol (SIP)",		Communications in the Session Initiation Protocol (SIP)",
	draft-ietf-sip-consent-framework-01 (work in progress),		draft-ietf-sip-consent-framework-02 (work in progress),
	November 2006.		July 2007.
	[I-D.jennings-sip-hashcash]		[I-D.jennings-sip-hashcash]
	Jennings, C., "Computational Puzzles for SPAM Reduction in		Jennings, C., "Computational Puzzles for SPAM Reduction in
	SIP", draft-jennings-sip-hashcash-05 (work in progress),		SIP", draft-jennings-sip-hashcash-05 (work in progress),
	June 2007.		June 2007.
	[I-D.rosenberg-sipping-service-identification]
	Rosenberg, J., "Identification of Communications Services
	in the Session Initiation Protocol (SIP)",
	draft-rosenberg-sipping-service-identification-02 (work in
	progress), May 2007.
	[RFC3693] Cuellar, J., Morris, J., Mulligan, D., Peterson, J., and
	J. Polk, "Geopriv Requirements", RFC 3693, February 2004.
	[RFC3880] Lennox, J., Wu, X., and H. Schulzrinne, "Call Processing		[RFC3880] Lennox, J., Wu, X., and H. Schulzrinne, "Call Processing
	Language (CPL): A Language for User Control of Internet		Language (CPL): A Language for User Control of Internet
	Telephony Services", RFC 3880, October 2004.		Telephony Services", RFC 3880, October 2004.
	[RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource
	Priority for the Session Initiation Protocol (SIP)",
	RFC 4412, February 2006.
	[RFC4474] Peterson, J. and C. Jennings, "Enhancements for		[RFC4474] Peterson, J. and C. Jennings, "Enhancements for
	Authenticated Identity Management in the Session		Authenticated Identity Management in the Session
	Initiation Protocol (SIP)", RFC 4474, August 2006.		Initiation Protocol (SIP)", RFC 4474, August 2006.
	[RFC4745] Schulzrinne, H., Tschofenig, H., Morris, J., Cuellar, J.,		[RFC4745] Schulzrinne, H., Tschofenig, H., Morris, J., Cuellar, J.,
	Polk, J., and J. Rosenberg, "Common Policy: A Document		Polk, J., and J. Rosenberg, "Common Policy: A Document
	Format for Expressing Privacy Preferences", RFC 4745,		Format for Expressing Privacy Preferences", RFC 4745,
	February 2007.		February 2007.
	Authors' Addresses		Authors' Addresses
End of changes. 30 change blocks.
	97 lines changed or deleted		62 lines changed or added
This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/