Security Implications of IPv6 Fragmentation with IPv6 Neighbor Discovery
draft-ietf-6man-nd-extension-headers-04

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IPv6 maintenance Working Group (6man)                            F. Gont
Internet-Draft                                    SI6 Networks / UTN-FRH
Updates: 3971, 4861 (if approved)                         March 22, 2013
Intended status: Standards Track
Expires: September 23, 2013

Security Implications of IPv6 Fragmentation with IPv6 Neighbor Discovery
                draft-ietf-6man-nd-extension-headers-04

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 counter-measures 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 prevented.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on September 23, 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

Gont                   Expires September 23, 2013               [Page 1]
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   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 . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Traditional Neighbor Discovery and IPv6 Fragmentation  . . . .  5
   3.  SEcure Neighbor Discovery (SEND) and IPv6 Fragmentation  . . .  6
   4.  Rationale for Forbidding IPv6 Fragmentation in Neighbor
       Discovery  . . . . . . . . . . . . . . . . . . . . . . . . . .  7
   5.  Specification  . . . . . . . . . . . . . . . . . . . . . . . .  8
   6.  Operational Advice . . . . . . . . . . . . . . . . . . . . . .  9
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     10.1.  Normative References  . . . . . . . . . . . . . . . . . . 13
     10.2.  Informative References  . . . . . . . . . . . . . . . . . 13
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15

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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, the 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.

   However, a number of factors, such as the use of trust anchors and
   the unavailability of SEND implementations for many widely-deployed
   operating systems, make SEND hard to deploy [Gont-DEEPSEC2011].
   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: