A method for mitigating namespace collisions
draft-wkumari-dnsop-defense-collision-mitigate-02

Network Working Group                                          W. Kumari
Internet-Draft                                                    Google
Intended status: Experimental                         September 17, 2013
Expires: March 21, 2014

              A method for mitigating namespace collisions
           draft-wkumari-dnsop-defense-collision-mitigate-02

Abstract

   This document outlines a possible, but not recommended, method to
   mitigate the effect of collisions in the DNS namespace by providing a
   means for end users to disambiguate the conflict.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on March 21, 2014.

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
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   described in the Simplified BSD License.

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Table of Contents

   1.  Introduction / Background . . . . . . . . . . . . . . . . . .   2
   2.  Mitigation  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Implementation / Disclaimers  . . . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   Appendix A.  Changes / Author Notes.  . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction / Background

   Collisions in the DNS occur in multiple ways; one common case is that
   an organization has used an sub-domain (foo) of their primary domain
   (example.com) for corporate infrastructure, and then the string "foo"
   is delegated as a TLD.  When an employee of the organization enters
   'www.foo', is the goal to reach a machine in the internal namespace
   (www.foo.example.com) or the hostname 'www' in the 'foo' TLD?

   This document describes a means of disambiguating these, and similar
   cases.

   Implementation of these methods are not recommended; they are
   documented here to explain some of the pitfalls with approaches like
   these.

2.  Mitigation

   The mitigation described in this document involves presenting the
   multiple options to the user, and allowing them to indicate which of
   the names is the one they were trying to reach.

   The mitigation would lookup the name in multiple namespaces.  When if
   a conflict is detected, it would then provide a means for the user to
   indicate which one of the colliding names they wish to connect to,
   and return the disambiguated answer to the application.  An
   additional feature could be for the mitigation to cache the user's
   choice, and / or provide a means to set priorities.

   This could be accomplished in a number of ways, including:

      Intercepting the resolution requests from the application in a
      "shim" type library

      Replacing the resolver library entirelyT

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      Integrating this type of mitigation into applications (some web
      browsers already do something similar to this)

      Proxying the request to a server that provides an interstitial
      page that allows the user to indicate the intended name (for
      applications such as HTTP requests)

   There are a number of issues with this solution, including but not
   limited to:

   o  There may not be a human available to disambiguate the answer
      (unattended machines, mail servers, etc.)

   o  The human / user may have no idea which is the correct choice,
      especially in the case of a phishing attackor other malicious
      intent

   o  The additional latency introduced may cause the originating
      application to time out

   o  The user experience would be time consuming to select each site
      and subsite intended (www.intranet, images.intranet, etc.)

   o  Caching the responses could lead to problems when the user changes
      location (internal sites would fail when offsite, or otherwise
      lead to incorrect sites being loaded)

   For these and other reasons, implementation of this technique is not
   recommended.

3.  Implementation / Disclaimers

   This document does not reference an implementation.  Due to the
   numerous issues described above, we do not recommend this solution be
   implemented.  We do not recommend that this be viewed as a solution
   to the namespace collision problem.

   This is a very slight mitigation.  It should not be viewed as a
   solution to the "namespace collision" issue.

4.  IANA Considerations

   This document contains no IANA considerations.

5.  Security Considerations

   While this method may make some users more aware of which version of
   a name they are going to (and so careful users may avoid some

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   phishing attacks), the security risks described above outweigh this
   potential benefit.

   There are numerous security implications in this approach, including
   leaking internal names (secret-project.corp.example.com), users being
   tricked into selecting the incorrect choice when trying to
   disambiguate answers, etc.

   For these reasons, it is not recommended that this solution be
   deployed.

6.  Acknowledgements

   The authors wish to thank some folk, including Fred Baker, Bob
   Braden, Carsten Bormann, Nevil Brownlee, Eric Burger, Brian
   Carpenter, Benoit Claise, Keith Drage, Martin J. Duerst, David
   Harrington, Paul Hoffamn, John Levine and Ted Lemon,

7.  References

Appendix A.  Changes / Author Notes.

   [RFC Editor: Please remove this section before publication.]

   From -00 to -01.

   o  Nothing changed in the template.

   from -01 to -02

   o  Rewrite.  Less flippant.

Author's Address

   Warren Kumari
   Google
   1600 Amphitheatre Parkway
   Mountain View, CA  94043
   US

   Email: warren@kumari.net

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