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Versions: (draft-luis140219-curdle-rc4-die-die-die) 00 01 02 03 04 05 06 07 08 09 10 11 12

Internet Engineering Task Force (IETF)                         L. Camara
Internet-Draft                                          January 10, 2018
Obsoletes: 4345
Updates: 4253
Intended Status: Best Current Practice
Expires: July 14, 2018


                 Depreciating RC4 in Secure Shell (SSH)
                  draft-ietf-curdle-rc4-die-die-die-05

[[RFC-Editor: please replace the second character of my surname by
U+00E2 when publishing as RFC in the header and in all pages.
Non-ASCII characters are allowed in RFCs as per RFC 7997.]]

Abstract

   This document depreciates RC4 in Secure Shell (SSH).  Therefore, this
   document updates RFC 4253, and formally obsoletes and moves to
   Historic RFC 4345.

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 July 14, 2018.

Copyright Notice

   Copyright (c) 2017 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
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   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.




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Table of Contents

   1. Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2. Why obsolete and move to Historic RFC 4345  . . . . . . . . . .  2
   3. Updates to RFC 4253 . . . . . . . . . . . . . . . . . . . . . .  2
   4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . .  2
   5. Security Considerations . . . . . . . . . . . . . . . . . . . .  3
   6. Acknowlegdements  . . . . . . . . . . . . . . . . . . . . . . .  3
   7. References  . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   7.1. Normative References  . . . . . . . . . . . . . . . . . . . .  3
   7.2. Informative References  . . . . . . . . . . . . . . . . . . .  3
   8. Author's Address  . . . . . . . . . . . . . . . . . . . . . . .  4

1. Introduction

   RC4 is extremely weak [RFC6649] [RFC7457] [RFC7465] and this document
   depreciates its use in all IETF protocols, including Kerberos and
   Secure Shell (SSH).  The reasons for obsoleting RFC 4345 are
   discussed in Section 2.  The updates to RFC 4253 and the reasons for
   doing them are specified in Section 3.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in
   BCP 14 [RFC2119, RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2. Why obsolete and move to Historic RFC 4345

   RFC 4345 defines the "arcfour-128" and "arcfour-256" modes for Secure
   Shell (SSH), and is obsoleted and moved to Historic as RC4 is
   extremely weak [RFC6649, RFC7457] and there is research that is at
   least 5 years old that totally breaks all practical usage of
   RC4 [RFC6649].

3. Updates to RFC 4253

   RFC 4253 is updated to note the depreciation of arcfour.

   The last sentence of the paragraph on RC4 (called "arcfour"
   in [RFC4253]) in Section 6.3 of [RFC4253] should read: "Arcfour (and
   RC4) are extremely weak [RFC7457] and therefore it MUST NOT be used."

   An informative reference to RFC 7457 is to be added to [RFC4253].

4. IANA Considerations

   IANA may need to take action as the status for RC4 and 3DES
   algorithms for Secure Shell (SSH) is changed by this document
   (see Section 3, that updates [RFC4253]).


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5. Security Considerations

   This document depreciates RC4, that is obsolete cryptography, and
   several attacks that render it useless have been published
   published [RFC6649] [RFC7457] [RFC7465].

6. Acknowledgements

   Thanks to the numerous authors which have shown the weaknesses of
   RC4 throughout the years.

7. References

7.1. Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in
              RFC 2119 Key Words", BCP 14, RFC 8174, May 2017.

7.2. Informative References

   [RFC4253]  Ylonen, T., and C. Lonvick, Ed., "The Secure Shell (SSH)
              Transport Layer Protocol", RFC 4253, January 2006.

   [RFC6151]  Turner, S., and L. Chen, "Updated Security Considerations
              for the MD5 Message-Digest and the HMAC-MD5 Algorithms",
              RFC 6151, March 2011.

   [RFC6649]  Hornquist Astrand, L. and T. Yu, "Deprecate DES, RC4-HMAC-
              EXP, and Other Weak Cryptographic Algorithms in Kerberos",
              BCP 179, RFC 6649, July 2012.

   [RFC7457]  Sheffer, Y., Holz, R., and P. Saint-Andre, "Summarizing
              Known Attacks on Transport Layer Security (TLS) and
              Datagram TLS (DTLS)", RFC 7457, February 2015.

   [RFC7465]  Popov, A., "Prohibiting RC4 Cipher Suites", RFC 7465,
              February 2015.

   [RFCxxxx]  Kaduk, B., and M. Short, "Deprecate 3DES and RC4 in
              Kerberos", draft-ietf-curdle-des-des-des-die-die-die-05,
              Work in Progress.







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   [[RFC-Editor: please replace the 'i' in my name by U+00ED and the
   first 'a' in the surname by U+00E2, as non-ASCII characters are
   allowed as per RFC 7997]]

11. Author's Address

   Luis Camara

   EMail: <luis.camara@live.com.pt>











































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