draft-ietf-6man-nd-extension-headers-01.txt   draft-ietf-6man-nd-extension-headers-02.txt 
IPv6 maintenance Working Group (6man) F. Gont IPv6 maintenance Working Group (6man) F. Gont
Internet-Draft SI6 Networks / UTN-FRH Internet-Draft SI6 Networks / UTN-FRH
Updates: 3971, 4861 (if approved) November 5, 2012 Updates: 3971, 4861 (if approved) December 10, 2012
Intended status: Standards Track Intended status: Standards Track
Expires: May 9, 2013 Expires: June 13, 2013
Security Implications of IPv6 Fragmentation with IPv6 Neighbor Discovery Security Implications of IPv6 Fragmentation with IPv6 Neighbor Discovery
draft-ietf-6man-nd-extension-headers-01 draft-ietf-6man-nd-extension-headers-02
Abstract Abstract
This document analyzes the security implications of using IPv6 This document analyzes the security implications of using IPv6
Extension Headers with Neighbor Discovery (ND) messages. It updates Extension Headers with Neighbor Discovery (ND) messages. It updates
RFC 4861 such that use of the IPv6 Fragmentation Header is forbidden RFC 4861 such that use of the IPv6 Fragmentation Header is forbidden
in all Neighbor Discovery messages, thus allowing for simple and in all Neighbor Discovery messages, thus allowing for simple and
effective counter-measures for Neighbor Discovery attacks. Finally, effective counter-measures for Neighbor Discovery attacks. Finally,
it discusses the security implications of using IPv6 fragmentation it discusses the security implications of using IPv6 fragmentation
with SEcure Neighbor Discovery (SEND), and formally updates RFC 3971 with SEcure Neighbor Discovery (SEND), and formally updates RFC 3971
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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 May 9, 2013. This Internet-Draft will expire on June 13, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 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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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Traditional Neighbor Discovery and IPv6 Fragmentation . . . . 5 2. Traditional Neighbor Discovery and IPv6 Fragmentation . . . . 5
3. SEcure Neighbor Discovery (SEND) and IPv6 Fragmentation . . . 6 3. SEcure Neighbor Discovery (SEND) and IPv6 Fragmentation . . . 6
4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . . 11
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.2. Informative References . . . . . . . . . . . . . . . . . . 11
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
The Neighbor Discovery Protocol (NDP) is specified in RFC 4861 The Neighbor Discovery Protocol (NDP) is specified in RFC 4861
[RFC4861] and RFC 4862 [RFC4862]. It is used by both hosts and [RFC4861] and RFC 4862 [RFC4862]. It is used by both hosts and
routers. Its functions include Neighbor Discovery (ND), Router routers. Its functions include Neighbor Discovery (ND), Router
Discovery (RD), Address Autoconfiguration, Address Resolution, Discovery (RD), Address Autoconfiguration, Address Resolution,
Neighbor Unreachability Detection (NUD), Duplicate Address Detection Neighbor Unreachability Detection (NUD), Duplicate Address Detection
(DAD), and Redirection. (DAD), and Redirection.
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o Certification Path Solicitation o Certification Path Solicitation
Nodes SHOULD normally process the following messages when the packets Nodes SHOULD normally process the following messages when the packets
carrying them include an IPv6 Fragmentation Header: carrying them include an IPv6 Fragmentation Header:
o Certification Path Advertisement o Certification Path Advertisement
SEND nodes SHOULD NOT employ keys that would result in fragmented CPA SEND nodes SHOULD NOT employ keys that would result in fragmented CPA
messages. messages.
5. Security Considerations 5. IANA Considerations
There are no IANA registries within this document. The RFC-Editor
can remove this section before publication of this document as an
RFC.
6. Security Considerations
The IPv6 Fragmentation Header can be leveraged to circumvent network The IPv6 Fragmentation Header can be leveraged to circumvent network
monitoring tools and current implementations of mechanisms such as monitoring tools and current implementations of mechanisms such as
RA-Guard [I-D.ietf-v6ops-ra-guard-implementation]. By updating the RA-Guard [I-D.ietf-v6ops-ra-guard-implementation]. By updating the
relevant specifications such that the IPv6 Fragment Header is not relevant specifications such that the IPv6 Fragment Header is not
allowed in any Neighbor Discovery messages except "Certification Path allowed in any Neighbor Discovery messages except "Certification Path
Advertisement", protection of local nodes against Neighbor Discovery Advertisement", protection of local nodes against Neighbor Discovery
attacks, and monitoring of Neighbor Discovery traffic is greatly attacks, and monitoring of Neighbor Discovery traffic is greatly
simplified. simplified.
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unless [RFC4861] is updated (as proposed in this document), Neighbor unless [RFC4861] is updated (as proposed in this document), Neighbor
Discovery monitoring tools (such as NDPMon [NDPMon]) would remain Discovery monitoring tools (such as NDPMon [NDPMon]) would remain
unreliable and trivial to circumvent by a skilled attacker. unreliable and trivial to circumvent by a skilled attacker.
As noted in Section 3, use of SEND could potentially result in As noted in Section 3, use of SEND could potentially result in
fragmented "Certification Path Advertisement" messages, thus allowing fragmented "Certification Path Advertisement" messages, thus allowing
an attacker to employ IPv6 fragmentation-based attacks against such an attacker to employ IPv6 fragmentation-based attacks against such
messages. Therefore, to the extent that is possible, such use of messages. Therefore, to the extent that is possible, such use of
fragmentation should be avoided. fragmentation should be avoided.
6. Acknowledgements 7. Acknowledgements
The author would like to thank (in alphabetical order) Mikael The author would like to thank (in alphabetical order) Mikael
Abrahamsson, Ran Atkinson, Ron Bonica, Jean-Michel Combes, David Abrahamsson, Ran Atkinson, Ron Bonica, Jean-Michel Combes, David
Farmer, Roque Gagliano, Bob Hinden, Philip Homburg, Ray Hunter, Farmer, Roque Gagliano, Bob Hinden, Philip Homburg, Ray Hunter,
Arturo Servin, and Mark Smith, for providing valuable comments on Arturo Servin, and Mark Smith, for providing valuable comments on
earlier versions of this document. earlier versions of this document.
This document resulted from the project "Security Assessment of the This document resulted from the project "Security Assessment of the
Internet Protocol version 6 (IPv6)" [CPNI-IPv6], carried out by Internet Protocol version 6 (IPv6)" [CPNI-IPv6], carried out by
Fernando Gont on behalf of the UK Centre for the Protection of Fernando Gont on behalf of the UK Centre for the Protection of
National Infrastructure (CPNI). The author would like to thank the National Infrastructure (CPNI). The author would like to thank the
UK CPNI, for their continued support. UK CPNI, for their continued support.
7. References 8. References
7.1. Normative References 8.1. 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.
[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
Neighbor Discovery (SEND)", RFC 3971, March 2005. Neighbor Discovery (SEND)", RFC 3971, March 2005.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862, September 2007.
7.2. Informative References 8.2. Informative References
[RFC3756] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor [RFC3756] Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor
Discovery (ND) Trust Models and Threats", RFC 3756, Discovery (ND) Trust Models and Threats", RFC 3756,
May 2004. May 2004.
[RFC6104] Chown, T. and S. Venaas, "Rogue IPv6 Router Advertisement [RFC6104] Chown, T. and S. Venaas, "Rogue IPv6 Router Advertisement
Problem Statement", RFC 6104, February 2011. Problem Statement", RFC 6104, February 2011.
[RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J. [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J.
Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105, Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105,
February 2011. February 2011.
[NDPMon] "NDPMon - IPv6 Neighbor Discovery Protocol Monitor", [NDPMon] "NDPMon - IPv6 Neighbor Discovery Protocol Monitor",
<http://ndpmon.sourceforge.net/>. <http://ndpmon.sourceforge.net/>.
[ramond] "ramond", <http://ramond.sourceforge.net/>. [ramond] "ramond", <http://ramond.sourceforge.net/>.
[I-D.ietf-v6ops-ra-guard-implementation] [I-D.ietf-v6ops-ra-guard-implementation]
Gont, F., "Implementation Advice for IPv6 Router Gont, F., "Implementation Advice for IPv6 Router
Advertisement Guard (RA-Guard)", Advertisement Guard (RA-Guard)",
draft-ietf-v6ops-ra-guard-implementation-05 (work in draft-ietf-v6ops-ra-guard-implementation-07 (work in
progress), October 2012. progress), November 2012.
[CPNI-IPv6] [CPNI-IPv6]
Gont, F., "Security Assessment of the Internet Protocol Gont, F., "Security Assessment of the Internet Protocol
version 6 (IPv6)", UK Centre for the Protection of version 6 (IPv6)", UK Centre for the Protection of
National Infrastructure, (available on request). National Infrastructure, (available on request).
[Gont-DEEPSEC2011] [Gont-DEEPSEC2011]
Gont, "Results of a Security Assessment of the Internet Gont, "Results of a Security Assessment of the Internet
Protocol version 6 (IPv6)", DEEPSEC 2011 Conference, Protocol version 6 (IPv6)", DEEPSEC 2011 Conference,
Vienna, Austria, November 2011, <http:// Vienna, Austria, November 2011, <http://
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