Security Implications of IPv6 Fragmentation with IPv6 Neighbor Discovery
RFC 6980
Document | Type | RFC - Proposed Standard (August 2013; No errata) | |
---|---|---|---|
Author | Fernando Gont | ||
Last updated | 2015-10-14 | ||
Replaces | draft-gont-6man-nd-extension-headers | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Bob Hinden | ||
Shepherd write-up | Show (last changed 2012-12-10) | ||
IESG | IESG state | RFC 6980 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Brian Haberman | ||
Send notices to | (None) | ||
IANA | IANA review state | IANA - Review Needed | |
IANA action state | No IANA Actions |
Internet Engineering Task Force (IETF) F. Gont Request for Comments: 6980 SI6 Networks / UTN-FRH Updates: 3971, 4861 August 2013 Category: Standards Track ISSN: 2070-1721 Security Implications of IPv6 Fragmentation with IPv6 Neighbor Discovery Abstract This document analyzes the security implications of employing IPv6 fragmentation with Neighbor Discovery (ND) messages. It updates RFC 4861 such that use of the IPv6 Fragmentation Header is forbidden in all Neighbor Discovery messages, thus allowing for simple and effective countermeasures for Neighbor Discovery attacks. Finally, it discusses the security implications of using IPv6 fragmentation with SEcure Neighbor Discovery (SEND) and formally updates RFC 3971 to provide advice regarding how the aforementioned security implications can be mitigated. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6980. Gont Standards Track [Page 1] RFC 6980 ND and IPv6 Fragmentation August 2013 Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction ....................................................2 2. Traditional Neighbor Discovery and IPv6 Fragmentation ...........4 3. SEcure Neighbor Discovery (SEND) and IPv6 Fragmentation .........5 4. Rationale for Forbidding IPv6 Fragmentation in Neighbor Discovery .......................................................6 5. Specification ...................................................6 6. Operational Advice ..............................................7 7. Security Considerations .........................................7 8. Acknowledgements ................................................8 9. References ......................................................8 9.1. Normative References .......................................8 9.2. Informative References .....................................9 Appendix A. Message Size When Carrying Certificates ...............10 1. Introduction The Neighbor Discovery Protocol (NDP) is specified in RFC 4861 [RFC4861]. It is used by both hosts and routers. Its functions include Neighbor Discovery (ND), Router Discovery (RD), address autoconfiguration, address resolution, Neighbor Unreachability Detection (NUD), Duplicate Address Detection (DAD), and redirection. Many of the possible attacks against the Neighbor Discovery Protocol are discussed in detail in [RFC3756]. In order to mitigate the aforementioned possible attacks, SEcure Neighbor Discovery (SEND) was standardized. SEND employs a number of mechanisms to certify the origin of Neighbor Discovery packets and the authority of routers, and to protect Neighbor Discovery packets from being the subject of modification or replay attacks. Gont Standards Track [Page 2] RFC 6980 ND and IPv6 Fragmentation August 2013 However, a number of factors, such as the high administrative overhead of deploying trust anchors and the unavailability of SEND implementations for many widely deployed operating systems, make SEND hard to deploy [Gont-DPSC]. Thus, in many general scenarios, it may be necessary and/or convenient to use other mitigation techniques for NDP-based attacks. The following mitigations are currently available for NDP attacks: o Static Access Control Lists (ACLs) in switches o Layer-2 filtering of Neighbor Discovery packets (such as RA-Guard [RFC6105]) o Neighbor Discovery monitoring tools (e.g., NDPMon [NDPMon] and ramond [ramond]) o Intrusion Prevention Systems (IPS)Show full document text