One document matched: draft-froment-sipping-spit-requirements-01.txt
Differences from draft-froment-sipping-spit-requirements-00.txt
SIPPING H. Tschofenig, Ed.
Internet-Draft Nokia Siemens Networks
Intended status: Informational G. Dawirs
Expires: January 10, 2008 University of Namur
T. Froment
Alcatel-Lucent
D. Wing
Cisco
H. Schulzrinne
Columbia University
July 9, 2007
Requirements for Authorization Policies to tackle Spam and Unwanted
Communication for Internet Telephony
draft-froment-sipping-spit-requirements-01.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
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
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 10, 2008.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Tschofenig, et al. Expires January 10, 2008 [Page 1]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Abstract
Spam over Internet Telephony (SPIT) is one of the foreseen future
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
intrusive. Email as a store-and-forward communication mechanism
allows for several filtering mechanisms to be applied to the full
content before being presented to the user. Session Initiation
Protocol (SIP) interaction is, in contrast, real-time communication
and therefore does not provide much information prior to the
transmission of the content, making it both harder to filter and more
annoying to users. The responsibility for filtering, blocking calls,
or taking any other preventive action can belong to different
elements in the call flow and may depend on various factors.
This document discusses the requirements to define authorization
policies that should allow end users or other parties to setup anti-
SPIT policies for triggering these actions. These policies typically
match a particular SIP communication pattern based on a number of
attributes. The range of attributes includes information provided,
for example, by the SIP protocol itself, by the SIP identity
mechanism, by information carried within SAML assertions, reputation
systems of social networks and other extensions.
Tschofenig, et al. Expires January 10, 2008 [Page 2]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Conditions . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Actions . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Transformations . . . . . . . . . . . . . . . . . . . . . 8
3.4. Generic Requirements . . . . . . . . . . . . . . . . . . . 8
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.2. References . . . . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
Intellectual Property and Copyright Statements . . . . . . . . . . 15
Tschofenig, et al. Expires January 10, 2008 [Page 3]
Internet-Draft SPIT Authorization Policy Requirements July 2007
1. Introduction
The problem of SPIT is an important challenge and it appears that a
combination of several techniques is desirable to provide a framework
to deal with it.
One important building block is to provide a mechanism to instruct a
trusted SIP proxy or any other SIP element to influence message
handling of incoming requests according to policies. Different
entities, such as end users, parents on behalf of their kids or
system administrators, might create and modify authorization
policies.
Some attributes in an incoming message play a more important role
than others. For example, applying authorization policies based on
the authenticated identity, see [RFC4474], is an effective way to
make decisions regarding unwanted traffic in many cases.
This document identifies requirements for authorization policies when
used to influence message handling for unwanted communicaion
attempts.
Tschofenig, et al. Expires January 10, 2008 [Page 4]
Internet-Draft SPIT Authorization Policy Requirements July 2007
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119],
with the important qualification that, unless otherwise stated, these
terms apply to the design of the authorization policies, not its
implementation or application.
Tschofenig, et al. Expires January 10, 2008 [Page 5]
Internet-Draft SPIT Authorization Policy Requirements July 2007
3. Requirements
This section lists the requirements categorized according to their
applicability for the "conditions", "actions" and "transformation"
parts typically found in authorization policies.
3.1. Conditions
The first set of requirements refer to identity related information.
Req-C 1: Policies MUST allow conditions to express single
authenticated identities.
Req-C 2: Policies MUST allow filtering based on the domain part of
the identity.
Req-C 3: Policies MUST support the differentiation between
authenticated and unauthenticated identities.
Req-C 4: Policies MUST be able to express exceptions within a group
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
SIP message header fields.
Req-C 6: Policies SHOULD allow conditions to refer to the
"destination" (which corresponds to the "Request-URI") and
"original-destination" (which corresponds to the "To" header).
Req-C 7: Policies SHOULD allow conditions to refer to the method
invoked by the caller (e.g., INVITE, REFER, MESSAGE).
Motivation: Some SIP methods are more intrusive than others
(the default applicative behaviour when SIP MESSAGEs are
received is often to pop-up the message on the UAS side),
adopting a different filtering policy depending of the method
invoked will enhance the user's protection.
Req-C 8: Policies SHOULD allow the entity that writes the rules to
take actions on messages that are marked as Spam.
Note that such a condition element should be seen in
context of the authenticated domain or or otherwise
protected information to avoid security
vulnerabilities.
Tschofenig, et al. Expires January 10, 2008 [Page 6]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Req-C 9: Policies MAY allow to make decisions based on the current
state of the user. E.g., based on a user selected active
profile, or sphere or other presence information.
Req-C 10: Policies SHOULD support consitions based on the content
type and/or offered (or used) media of a message.
Message handling might be different based on time.
Req-C 11: Policies SHOULD allow conditions that refer to the
reception date, time, timezone or period of time of the
incoming request.
Message handling might be different based on the language.
Req-C 12: Policies SHOULD allow to make decisions based on the
languages in which the originator of the call wishes to
communicate.
3.2. Actions
Req-A 1: Policies SHOULD allow messages to get "blocked", i.e., to
stop forwarding the request and to return an answer with a
``403 Forbidden''
Req-A 2: Policies SHOULD allow messages to get "politely blocked",
i.e., to drop the request without returning an answer.
Req-A 3: Policies SHOULD allow messages to get "marked", i.e., to
forward the request and mark it as "potential Spam" for
filtering at the end point or at subsequent entities along the
signaling path.
Req-A 4: Policies SHOULD allow messages to be "allowed", i.e., to
forward this message.
Req-A 5: Policies MUST allow messages to be "redirected" to, for
example, voicemail or to a different device in the possession
of the user.
Req-A 6: Policies MUST allow executing other SPIT prevention
procedures, such as computational puzzles
[I-D.jennings-sip-hashcash] or the consent framework"
[I-D.ietf-sip-consent-framework]. A specification developing
a SPIT prevention mechanism should provide information on how
they can be incorporated into the authorization policy
framework.
Tschofenig, et al. Expires January 10, 2008 [Page 7]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Req-A 7: Policies MAY allow an e-mail (or SMS, MMS) or other
notifications to be sent to the user about the actions taken
due to a specific call attempt.
3.3. Transformations
Req-T 1: Policies SHOULD allow SIP messages to be marked with a
certain SPIT probability in case SPIT detection and policy
enforcement is excecuted on different entities. For example,
a network element might run a statistical SPIT detection tool
but the authorization policies are executed on a different
entity, such as the end host. Note that it needs to be
ensured that an adversary is not able to set the SPIT
probabity values since otherwise the authorization policies
that rely on such information are misguided.
3.4. Generic Requirements
Req-G 1: It SHOULD be possible to allow a hierarchy of authorization
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
authorization policy capabilities implemented by the server.
Req-G 3: Policies MUST be extensible and these extensions MUST exist
within a different namespace. Furthermore, a published schema
and the namespace for elements defined within it MUST NOT be
altered by future specifications.
Req-G 4: The policies MUST provide a mandatory-to-implement conflict
resolution mechanism.
Tschofenig, et al. Expires January 10, 2008 [Page 8]
Internet-Draft SPIT Authorization Policy Requirements July 2007
4. IANA Considerations
This document does not require actions by IANA.
Tschofenig, et al. Expires January 10, 2008 [Page 9]
Internet-Draft SPIT Authorization Policy Requirements July 2007
5. Security Considerations
This document describes the requirements for elements contained in
the authorization policies that allow communication attempts to be
treated differently based on the content of the message, time-of-day,
context of the user, reputation of the sending party, and many other
factors.
The security concerns are related to the ability of certain entities
to create, update and delete authorization policies. If an
unauthorized entity is allowed to modify policies (and to distribute
them to other domains) then a denial of service attack is the
consequence with impact for more than a single end point. These
security aspects are, however, not subject of this document.
Tschofenig, et al. Expires January 10, 2008 [Page 10]
Internet-Draft SPIT Authorization Policy Requirements July 2007
6. Acknowledgements
The content of this document is inspired by the work of CPL
[RFC3880], SIEVE [I-D.ietf-sieve-3028bis], Common Policy [RFC4745]
and Presence Authorization Policy [I-D.ietf-simple-presence-rules].
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.
Tschofenig, et al. Expires January 10, 2008 [Page 11]
Internet-Draft SPIT Authorization Policy Requirements July 2007
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
7.2. References
[I-D.ietf-sieve-3028bis]
Showalter, T. and P. Guenther, "Sieve: An Email Filtering
Language", draft-ietf-sieve-3028bis-12 (work in progress),
February 2007.
[I-D.ietf-simple-presence-rules]
Rosenberg, J., "Presence Authorization Rules",
draft-ietf-simple-presence-rules-10 (work in progress),
July 2007.
[I-D.ietf-sip-consent-framework]
Rosenberg, J., "A Framework for Consent-Based
Communications in the Session Initiation Protocol (SIP)",
draft-ietf-sip-consent-framework-02 (work in progress),
July 2007.
[I-D.jennings-sip-hashcash]
Jennings, C., "Computational Puzzles for SPAM Reduction in
SIP", draft-jennings-sip-hashcash-05 (work in progress),
June 2007.
[RFC3880] Lennox, J., Wu, X., and H. Schulzrinne, "Call Processing
Language (CPL): A Language for User Control of Internet
Telephony Services", RFC 3880, October 2004.
[RFC4474] Peterson, J. and C. Jennings, "Enhancements for
Authenticated Identity Management in the Session
Initiation Protocol (SIP)", RFC 4474, August 2006.
[RFC4745] Schulzrinne, H., Tschofenig, H., Morris, J., Cuellar, J.,
Polk, J., and J. Rosenberg, "Common Policy: A Document
Format for Expressing Privacy Preferences", RFC 4745,
February 2007.
Tschofenig, et al. Expires January 10, 2008 [Page 12]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Authors' Addresses
Hannes Tschofenig (editor)
Nokia Siemens Networks
Otto-Hahn-Ring 6
Munich, Bavaria 81739
Germany
Email: Hannes.Tschofenig@nsn.com
URI: http://www.tschofenig.com
Geoffrey Dawirs
University of Namur
21, rue Grandgagnage
Namur B-5000
Belgique
Email: gdawirs@gdawirs.be
Thomas Froment
Alcatel-Lucent
Route de Villejust
Nozay, Paris 91620
France
Email: Thomas.Froment@alcatel-lucent.fr
Dan Wing
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: dwing@cisco.com
Tschofenig, et al. Expires January 10, 2008 [Page 13]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Henning Schulzrinne
Columbia University
Department of Computer Science
450 Computer Science Building
New York, NY 10027
US
Phone: +1 212 939 7004
Email: hgs@cs.columbia.edu
URI: http://www.cs.columbia.edu
Tschofenig, et al. Expires January 10, 2008 [Page 14]
Internet-Draft SPIT Authorization Policy Requirements July 2007
Full Copyright Statement
Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
Tschofenig, et al. Expires January 10, 2008 [Page 15]
| PAFTECH AB 2003-2026 | 2026-04-22 16:29:09 |