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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

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
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   This Internet-Draft will expire on November 17, 2007.

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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Full Copyright Statement

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Acknowledgment

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).





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