draft-ietf-curdle-rc4-die-die-die-15.txt   draft-ietf-curdle-rc4-die-die-die-16.txt 
Internet Engineering Task Force L. Camara Internet Engineering Task Force L. Camara
Internet-Draft Internet-Draft
Obsoletes: 4345 (if approved) L. Velvindron Updates: 4253 (if approved) L. Velvindron
Intended status: Best Current Practice cyberstorm.mu Intended status: Best Current Practice cyberstorm.mu
Expires: July 20, 2019 January 16, 2019 Expires: January 31, 2020 July 30, 2019
Deprecating RC4 in Secure Shell (SSH) Deprecating RC4 in Secure Shell (SSH)
draft-ietf-curdle-rc4-die-die-die-15 draft-ietf-curdle-rc4-die-die-die-16
Abstract Abstract
This document deprecates RC4 in Secure Shell (SSH). Therefore, this This document deprecates RC4 in Secure Shell (SSH). Therefore, this
document formally obsoletes and moves to Historic RFC4345. document formally moves to Historic RFC4345.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 20, 2019. This Internet-Draft will expire on January 31, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 24 skipping to change at page 2, line 24
6.1. Normative References . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction 1. Introduction
The usage of RC4 suites ( also designated as arcfour ) for SSH are The usage of RC4 suites ( also designated as arcfour ) for SSH are
specified in [RFC4253] and [RFC4345]. [RFC4253] specifies the specified in [RFC4253] and [RFC4345]. [RFC4253] specifies the
allocation of the "arcfour" cipher for SSH. [RFC4345] specifies and allocation of the "arcfour" cipher for SSH. [RFC4345] specifies and
allocates the "arcfour-128" and "arcfour-256" ciphers for SSH. RC4 allocates the "arcfour-128" and "arcfour-256" ciphers for SSH. RC4
encryption has known weaknesses [RFC7465] encryption has known weaknesses [RFC7465] [RFC8429], and the
[I-D.ietf-curdle-des-des-des-die-die-die], and the deprecation deprecation process should be begun for their use in Secure Shell
process should be begun for their use in Secure Shell (SSH) (SSH) [RFC4253]. Accordingly, [RFC4253] is updated to note the
[RFC4253]. Accordingly, [RFC4253] is updated to note the deprecation deprecation of the RC4 ciphers and [RFC4345] is moved to Historic as
of the RC4 ciphers and [RFC4345] is moved to Historic as all ciphers all ciphers it specifies MUST NOT be used.
it specifies MUST NOT be used.
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119]RFC
8174 [RFC8174] when, and only when, they appear in all capitals, as
shown here.
2. Updates to RFC 4253 2. Updates to RFC 4253
[RFC4253] is updated to prohibit arcfour's use in SSH. [RFC4253] [RFC4253] is updated to prohibit arcfour's use in SSH. [RFC4253]
allocates the "arcfour" cipher in Section 6.3 by defining a list of allocates the "arcfour" cipher in Section 6.3 by defining a list of
defined ciphers where the "arcfour" cipher appears as optional as defined ciphers where the "arcfour" cipher appears as optional as
mentioned below: mentioned below:
+---------------+-----------------+---------------------------------+ +---------------+-----------------+---------------------------------+
| arcfour | OPTIONAL | the ARCFOUR stream cipher with | | arcfour | OPTIONAL | the ARCFOUR stream cipher with |
skipping to change at page 3, line 23 skipping to change at page 3, line 23
The "arcfour" cipher is the Arcfour stream cipher with 128-bit keys. The "arcfour" cipher is the Arcfour stream cipher with 128-bit keys.
The Arcfour cipher is compatible with the RC4 cipher [SCHNEIER]. The Arcfour cipher is compatible with the RC4 cipher [SCHNEIER].
Arcfour (and RC4) has problems with weak keys, and should be used Arcfour (and RC4) has problems with weak keys, and should be used
with caution. with caution.
The current document updates [RFC4253] Section 6.3 by replacing the The current document updates [RFC4253] Section 6.3 by replacing the
text above with the following text: text above with the following text:
The "arcfour" cipher is the Arcfour stream cipher with 128-bit keys. The "arcfour" cipher is the Arcfour stream cipher with 128-bit keys.
The Arcfour cipher is compatible with the RC4 cipher [SCHNEIER]. The Arcfour cipher is compatible with the RC4 cipher [SCHNEIER].
Arcfour (and RC4) has known weakenesses [RFC7465] Arcfour (and RC4) has known weakenesses [RFC7465] [RFC8429], and MUST
[I-D.ietf-curdle-des-des-des-die-die-die], and MUST NOT be used. NOT be used.
3. IANA Considerations 3. IANA Considerations
The IANA is requested to update the Encryption Algorithm Name The IANA is requested to update the Encryption Algorithm Name
Registry of the Secure Shell (SSH) Protocol Parameters [IANA]. The Registry of the Secure Shell (SSH) Protocol Parameters [IANA]. The
Registration procedure is IETF Review which is achieved by this Registration procedure is IETF Review which is achieved by this
document. The registry should be updated as follows: document. The registry should be updated as follows:
+-------------+------------------------------------+ +------------------------------+------------+------+
| Encryption | Algorithm Name Reference Note | | Encryption Algorithm Name | Reference | Note |
+-------------+------------------------------------+ +------------------------------+------------+------+
| arcfour | [RFC-TBD] | | arcfour | [RFC-TBD] | |
| arcfour128 | [RFC-TBD] | | arcfour128 | [RFC-TBD] | |
| arcfour256 | [RFC-TBD] | | arcfour256 | [RFC-TBD] | |
+-------------+------------------------------------+ +------------------------------+------------+------+
Where TBD is the RFC number assigned to the document. Where TBD is the RFC number assigned to the document.
4. Acknowledgements 4. Acknowledgements
The authors would like to thank Eric Rescorla, Daniel Migault and The authors would like to thank Eric Rescorla, Daniel Migault and
Rich Salz. Rich Salz.
5. Security Considerations 5. Security Considerations
skipping to change at page 4, line 14 skipping to change at page 4, line 14
6. References 6. References
6.1. Normative References 6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
6.2. Informative References [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[I-D.ietf-curdle-des-des-des-die-die-die] 6.2. Informative References
Kaduk, B. and M. Short, "Deprecate 3DES and RC4 in
Kerberos", draft-ietf-curdle-des-des-des-die-die-die-05
(work in progress), September 2017.
[IANA] "Secure Shell (SSH) Protocol Parameters: Encryption [IANA] "Secure Shell (SSH) Protocol Parameters: Encryption
Algorithm Names", <https://www.iana.org/assignments/ssh- Algorithm Names", <https://www.iana.org/assignments/ssh-
parameters/ssh-parameters.xhtml#ssh-parameters-17>. parameters/ssh-parameters.xhtml#ssh-parameters-17>.
[RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) [RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253, Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
January 2006, <https://www.rfc-editor.org/info/rfc4253>. January 2006, <https://www.rfc-editor.org/info/rfc4253>.
[RFC4345] Harris, B., "Improved Arcfour Modes for the Secure Shell [RFC4345] Harris, B., "Improved Arcfour Modes for the Secure Shell
(SSH) Transport Layer Protocol", RFC 4345, (SSH) Transport Layer Protocol", RFC 4345,
DOI 10.17487/RFC4345, January 2006, DOI 10.17487/RFC4345, January 2006,
<https://www.rfc-editor.org/info/rfc4345>. <https://www.rfc-editor.org/info/rfc4345>.
[RFC7465] Popov, A., "Prohibiting RC4 Cipher Suites", RFC 7465, [RFC7465] Popov, A., "Prohibiting RC4 Cipher Suites", RFC 7465,
DOI 10.17487/RFC7465, February 2015, DOI 10.17487/RFC7465, February 2015,
<https://www.rfc-editor.org/info/rfc7465>. <https://www.rfc-editor.org/info/rfc7465>.
[RFC8429] Kaduk, B. and M. Short, "Deprecate Triple-DES (3DES) and
RC4 in Kerberos", BCP 218, RFC 8429, DOI 10.17487/RFC8429,
October 2018, <https://www.rfc-editor.org/info/rfc8429>.
[SCHNEIER] [SCHNEIER]
Schneier, B., "Applied Cryptography Second Edition: Schneier, B., "Applied Cryptography Second Edition:
protocols algorithms and source in code in C", , 1996, protocols algorithms and source in code in C", , 1996,
<SCHNEIER>. <SCHNEIER>.
Authors' Addresses Authors' Addresses
Luis Camara Luis Camara
Email: luis.camara@live.com.pt Email: luis.camara@live.com.pt
Loganaden Velvindron Loganaden Velvindron
cyberstorm.mu cyberstorm.mu
Mauritius Mauritius
Email: loganaden@gmail.com Email: logan@cyberstorm.mu
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