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Versions: 00 01 RFC 5095
Network Working Group J. Abley
Internet-Draft Afilias
Updates: 2460 (if approved) P. Savola
Intended status: Standards Track CSC/FUNET
Expires: November 17, 2007 G. Neville-Neil
Neville-Neil Consulting
May 16, 2007
Deprecation of Type 0 Routing Headers in IPv6
draft-ietf-ipv6-deprecate-rh0-00
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Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
The functionality provided by IPv6's Type 0 Routing Header can be
exploited in order to perform remote network discovery, to bypass
firewalls and to achieve packet amplification for the purposes of
generating denial-of-service traffic. This document updates the IPv6
specification to deprecate the use of IPv6 Type 0 Routing Headers, in
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the light of these security concerns.
This document updates RFC 2460.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Deprecation of RH0 . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Origination . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Processing . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Operations . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4.1. Ingress Filtering . . . . . . . . . . . . . . . . . . . . . 3
4.2. Packet Filtering . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
7. Acknowlegements . . . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . . 5
Appendix A. Change History . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 7
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1. Introduction
[RFC2460] defines an IPv6 extension header called "Routing Header",
identified by a Next Header value of 43 in the immediately preceding
header. A particular Routing Header subtype denoted as "Type 0" is
also defined. Type 0 Routing Headers are referred to as "RH0" in
this document.
Use of RH0 has been shown to have unpleasant security implications,
some of which are summarised in Section 5. This document deprecates
the use of RH0.
This document updates [RFC2460].
2. Definitions
RH0 in this document denotes the IPv6 Extension Header type 43
("Routing Header") variant 0 ("Type 0 Routing Header"), as defined in
[RFC2460].
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 [RFC2119].
3. Deprecation of RH0
3.1. Origination
IPv6 nodes MUST NOT originate IPv6 packets containing RH0.
3.2. Processing
IPv6 nodes MUST NOT process RH0 in packets addressed to them. Such
packets MUST be processed according to the behaviour specified in
Section 4.4 of [RFC2460] for a datagram which includes an
unrecognised Routing Type value.
4. Operations
4.1. Ingress Filtering
It is to be expected that it will take some time before all IPv6
nodes are updated to remove support for RH0. Some of the uses of RH0
described in [CanSecWest07] can be mitigated using ingress filtering,
as recommended in [RFC2827] and [RFC3704].
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4.2. Packet Filtering
Firewall policy intended to protect against packets containing RH0
should be constructed such that routing headers of other types (which
may well have legitimate and benign applications) are handled on
their own merits. For example, discarding all packets with any type
of routing header simply as a reaction to the problems with RH0 is
inappropriate, and may hamper future functionality designed using
non-type 0 routing headers. For example, Mobile IPv6 uses the type 2
Routing Header [RFC3775].
Where filtering capabilities do not facilitate matching specific
types of Routing Headers, filtering based on the presence of any
Routing Headers on IPv6 routers, regardless of type, is strongly
discouraged.
5. Security Considerations
The purpose of this document is to deprecate a feature of IPv6 which
has been shown to have serious security implications.
Specific examples of vulnerabilities which are facilitated by the
availability of RH0 can be found in [CanSecWest07].
6. IANA Considerations
The IANA registry "Internet Protocol Version 6 (IPv6) Parameters"
should be updated to reflect that variant 0 of IPv6 header-type 43
("Routing Header") is deprecated.
7. Acknowlegements
Potential problems with Routing Headers were identified in 2001
[I-D.savola-ipv6-rh-ha-security]. In 2002 a proposal was made to
restrict Routing Header processing in hosts
[I-D.savola-ipv6-rh-hosts]. These efforts did not gain sufficient
momentum to change the IPv6 specification, but resulted in the
modification of the Mobile IPv6 specification to use the type 2
Routing Header instead of RH0 [RFC3775]. Routing Header issues were
later documented in [I-D.ietf-v6ops-security-overview].
An eloquent and useful description of the operational security
implications of RH0 was presented by Philippe Biondi and Arnaud
Ebalard at the CanSecWest conference in Vancouver, 2007
[CanSecWest07]. This presentation resulted in widespread publicity
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for the risks associated with RH0.
This document also benefits from the contributions of IPv6 and V6OPS
orking group participants, including Jari Arkko, Arbaud Ebalard, Tim
Enos, Brian Haberman, Jun-ichiro itojun HAGINO, Bob Hinden, JINMEI
Tatuya, David Malone, Jeroen Massar, Dave Thaler and Guillaume
Valadon.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
8.2. Informative References
[CanSecWest07]
BIONDI, P. and A. EBALARD, "IPv6 Routing Header Security",
April 2007.
http://www.secdev.org/conf/IPv6_RH_security-csw07.pdf
[I-D.ietf-v6ops-security-overview]
Davies, E., "IPv6 Transition/Co-existence Security
Considerations", draft-ietf-v6ops-security-overview-06
(work in progress), October 2006.
[I-D.savola-ipv6-rh-ha-security]
Savola, P., "Security of IPv6 Routing Header and Home
Address Options", draft-savola-ipv6-rh-ha-security-02
(work in progress), March 2002.
[I-D.savola-ipv6-rh-hosts]
Savola, P., "Note about Routing Header Processing on IPv6
Hosts", draft-savola-ipv6-rh-hosts-00 (work in progress),
February 2002.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed
Networks", BCP 84, RFC 3704, March 2004.
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[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
Appendix A. Change History
This section to be removed prior to publication.
00 Strawman, draft-jabley-ipv6-rh0-is-evil, circulated to provoke
discussion.
01 Clarified Section 3; presented more options in Section 4; added
Pekka and George as authors. This document version was not widely
circulated.
00 Renamed, draft-ietf-ipv6-deprecate-rh0, a candidate working group
document.
Authors' Addresses
Joe Abley
Afilias Canada Corp.
Suite 204, 4141 Yonge Street
Toronto, ON M2P 2A8
Canada
Phone: +1 416 673 4176
Email: jabley@ca.afilias.info
Pekka Savola
CSC/FUNET
Espoo,
Finland
Email: psavola@funet.fi
George Neville-Neil
Neville-Neil Consulting
2261 Market St. #239
San Francisco, CA 94114
USA
Email: gnn@neville-neil.com
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