Teredo Security Updates
RFC 5991

 
Document Type RFC - Proposed Standard (September 2010; No errata)
Updates RFC 4380
Was draft-krishnan-v6ops-teredo-update (individual in int area)
Last updated 2013-03-02
Stream IETF
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Stream WG state (None)
Consensus Unknown
Document shepherd No shepherd assigned
IESG IESG state RFC 5991 (Proposed Standard)
Telechat date
Responsible AD Jari Arkko
Send notices to dthaler@microsoft.com, suresh.krishnan@ericsson.com, Jim_Hoagland@symantec.com, draft-krishnan-v6ops-teredo-update@ietf.org

Email authors IPR 3 References Referenced by Nits Search lists

Internet Engineering Task Force (IETF)                         D. Thaler
Request for Comments: 5991                                     Microsoft
Updates: 4380                                                S. Krishnan
Category: Standards Track                                       Ericsson
ISSN: 2070-1721                                              J. Hoagland
                                                                Symantec
                                                          September 2010

                        Teredo Security Updates

Abstract

   The Teredo protocol defines a set of flags that are embedded in every
   Teredo IPv6 address.  This document specifies a set of security
   updates that modify the use of this flags field, but are backward
   compatible.

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/rfc5991.

Copyright Notice

   Copyright (c) 2010 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.

Thaler, et al.               Standards Track                    [Page 1]
RFC 5991                 Teredo Security Updates          September 2010

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................3
   3. Specification ...................................................4
      3.1. Random Address Flags .......................................4
      3.2. Deprecation of Cone Bit ....................................6
   4. Security Considerations .........................................7
   5. Acknowledgments .................................................7
   6. References ......................................................8
      6.1. Normative References .......................................8
      6.2. Informative References .....................................8
   Appendix A.  Implementation Status .................................9
   Appendix B.  Resistance to Address Prediction ......................9

1.  Introduction

   Teredo [RFC4380] defines a set of flags that are embedded in every
   Teredo IPv6 address.  This document specifies a set of security
   updates that modify the use of this flags field, but are backwards
   compatible.  This document updates RFC 4380.

   The Flags field in a Teredo IPv6 address has 13 unused bits out of a
   total of 16 bits.  To guard against address-scanning risks [RFC5157]
   from malicious users, this update randomizes 12 of the 13 unused bits
   when configuring the Teredo IPv6 address.  Even if an attacker were
   able to determine the external (mapped) IPv4 address and port
   assigned by a NAT to the Teredo client, the attacker would still need
   to attack a range of 4,096 IPv6 addresses to determine the actual
   Teredo IPv6 address of the client.

   The cone bit in a Teredo IPv6 address indicates whether a peer needs
   to send Teredo control messages before communicating with a Teredo
   IPv6 address.  Unfortunately, it may also have some value in terms of
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