draft-ietf-curdle-rc4-die-die-die-02.txt		draft-ietf-curdle-rc4-die-die-die-03.txt
	Internet Engineering Task Force (IETF) L. Camara		Internet Engineering Task Force (IETF) L. Camara
	Internet-Draft August 8, 2017		Internet-Draft December 9, 2017
	Obsoletes: 4345		Obsoletes: 4345
	Updates: 3501, 4253, 6649, 6733		Updates: 3501, 4253, 6649, 6733
	Intended Status: Best Current Practice		Intended Status: Best Current Practice
	Expires: February 9, 2018		Expires: June 12, 2018
	Deprecating RC4 in all IETF Protocols		Depreciating RC4 in all IETF Protocols
	draft-ietf-curdle-rc4-die-die-die-02		draft-ietf-curdle-rc4-die-die-die-03
	[[RFC-Editor: Please replace all instances of xxxx in this document with		[[RFC-Editor: Please replace all instances of xxxx in this document with
	the RFC number of draft-ietf-curdle-des-des-des-die-die-die.]]		the RFC number of draft-ietf-curdle-des-des-des-die-die-die.]]
	[[RFC-Editor: please replace the second character of my surname by		[[RFC-Editor: please replace the second character of my surname by
	U+00E2 when publishing as RFC in the header and in all pages.		U+00E2 when publishing as RFC in the header and in all pages.
	Non-ASCII characters are allowed in RFCs as per RFC 7997.]]		Non-ASCII characters are allowed in RFCs as per RFC 7997.]]
	Abstract		Abstract
	skipping to change at page 1, line 44 ¶		skipping to change at page 1, line 44 ¶
	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 http://datatracker.ietf.org/drafts/current/.		Drafts is at http://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 January 4, 2018.		This Internet-Draft will expire on June 12, 2018.
	Copyright Notice		Copyright Notice
	Copyright (c) 2017 IETF Trust and the persons identified as the		Copyright (c) 2017 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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://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 36 ¶		skipping to change at page 2, line 36 ¶
	10. Acknowlegdements . . . . . . . . . . . . . . . . . . . . . . . 5		10. Acknowlegdements . . . . . . . . . . . . . . . . . . . . . . . 5
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6		11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
	11.1. Normative References . . . . . . . . . . . . . . . . . . . . 6		11.1. Normative References . . . . . . . . . . . . . . . . . . . . 6
	11.2. Informative References . . . . . . . . . . . . . . . . . . . 6		11.2. Informative References . . . . . . . . . . . . . . . . . . . 6
	12. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 7		12. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 7
	Appendix A. Changelog . . . . . . . . . . . . . . . . . . . . . . 8		Appendix A. Changelog . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	RC4 is extremely weak [RFC6649] [RFC7457] [RFCxxxx] and this document		RC4 is extremely weak [RFC6649] [RFC7457] [RFCxxxx] and this document
	deprecates its use in all IETF protocols, including Kerberos and		depreciates its use in all IETF protocols, including Kerberos and
	Secure Shell (SSH). The reasons for obsoleting RFC 4345 are discussed		Secure Shell (SSH). The reasons for obsoleting RFC 4345 are
	in Section 2. The updates to RFC 3501, RFC 4253, RFC 6649 and RFC		discussed in Section 2. The updates to RFC 3501, RFC 4253, RFC 6649
	RFC 6733 and the reasons for doing them are specified in sections 3,		and RFC 6733 and the reasons for doing them are specified in sections
	4, 5 and 6, respectively.		3, 4, 5 and 6, respectively.
	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		document are to be interpreted as described in
	BCP 14 [RFC2119, RFC8174].		BCP 14 [RFC2119, RFC8174].
	2. Why obsolete RFC 4345		2. Why obsolete RFC 4345
	RFC 4345 defines the "arcfour-128" and "arcfour-256" modes for Secure		RFC 4345 defines the "arcfour-128" and "arcfour-256" modes for Secure
	Shell (SSH), and is moved to Historic as RC4 is extremely		Shell (SSH), and is moved to Historic as RC4 is extremely
	weak [RFC6649, RFC7457, RFCxxxx] and there is research that is at		weak [RFC6649, RFC7457, RFCxxxx] and there is research that is at
	least 5 years old that totally breaks all practical usage of		least 5 years old that totally breaks all practical usage of
	RC4 [RFC6649].		RC4 [RFC6649].
	3. Updates to RFC 3501		3. Updates to RFC 3501
	The second paragraph of [RFC3501] required that implementations of		The second paragraph of [RFC3501] required that implementations of
	IMAP clients and servers implement a RC4 cipher suite in TLS		IMAP clients and servers implement a RC4 cipher suite in TLS
	(contradicts [RFC7465]) and recommends implementing a weak cipher		(contradicts [RFC7465]) and recommends implementing a weak cipher
	suite (3DES is used in the suite). Unfortunately, at the time of		suite (3DES is used in the suite). Unfortunately, at the time of
	writing of RFC 3501, AES cipher suites were extremely new (the first		writing of RFC 3501, AES cipher suites were extremely new (the first
	AES cipher suites were defined in RFC 3268, published in June 2002),		AES cipher suites were defined in RFC 3268, published in June 2002),
	less than 1 year old and the strongest choice they have come up with		less than 1 year old and the strongest choice they have come up with
	at the time was TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA.		at the time was TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA.
	As the document is over 14 years old, the second paragraph of		As the document is over 14 years old, the second paragraph of
	Section 11.1 of [RFC3501] is replaced with the following paragraph:		Section 11.1 of [RFC3501] is replaced with the following paragraph:
	"""		"""
	IMAP client and server implementations were formerly required to		IMAP client and server implementations were formerly required to
	implement TLS_RSA_WITH_RC4_128_MD5 {TLS}, an extremely weak cipher		implement TLS_RSA_WITH_RC4_128_MD5 {TLS}, an extremely weak cipher
	suite [RFC6151] [RFC6649] [RFC7457] [RFCxxxx] [RFCyyyy] that TLS		suite [RFC6151] [RFC6649] [RFC7457] [RFCxxxx] [RFCyyyy] that TLS
	clients MUST NOT implement per [RFC7465]. Compatibility requirements		clients MUST NOT implement per [RFC7465]. Compatibility requirements
	were removed in the grounds of security, and all clients and servers		were removed in the grounds of security, and all clients and servers
	SHOULD comply to [RFC7525].		SHOULD comply to [RFC7525].
	"""		"""
	The TLS reference in [RFC3501] should be replaced with a reference to		The TLS reference in [RFC3501] should be replaced with a reference to
	RFC 5246, and references to RFC 6151, RFC 6649, RFC 7457, RFC 7465,		RFC 5246, and references to RFC 6151, RFC 6649, RFC 7457, RFC 7465,
	RFC xxxx and this document (as RFC yyyy) should be added.		RFC xxxx and this document (as RFC yyyy) should be added.
	4. Updates to RFC 4253		4. Updates to RFC 4253
	RFC 4253 is updated to note the deprecation of arcfour and 3des-cbc.		RFC 4253 is updated to note the deprecation of arcfour and 3des-cbc.
	This document changes "OPTIONAL" to "NOT RECOMMENDED" for arcfour and		This document changes "OPTIONAL" to "NOT RECOMMENDED" for arcfour and
	"REQUIRED" to "OPTIONAL" for 3des-cbc in the table of		"REQUIRED" to "OPTIONAL" for 3des-cbc in the table of
	Section 6.3 of [RFC4253] as 3DES is weak and maintaining the		Section 6.3 of [RFC4253] as 3DES is weak and maintaining the
	requirement will compromise systems. [RFC4253] was published in 2006,		requirement will compromise systems. [RFC4253] was published in
	11 years ago, and states that """At some future time, it is expected		2006, 11 years ago, and states that """At some future time, it is
	that another algorithm, one with better strength, will become so		expected that another algorithm, one with better strength, will
	prevalent and ubiquitous that the use of "3des-cbc" will be		become so prevalent and ubiquitous that the use of "3des-cbc" will be
	deprecated by another STANDARDS ACTION."""		deprecated by another STANDARDS ACTION."""
	The "future time" referred to by [RFC4253] is set to 2017, the		The "future time" referred to by [RFC4253] is set to 2017, the
	"STANDARDS ACTION" is set to the publication of this document and		"STANDARDS ACTION" is set to the publication of this document and
	the "algorithm" is set to the Advanced Encryption Standard (AES), as		the "algorithm" is set to the Advanced Encryption Standard (AES), as
	AES is ubiquitous in Kerberos implementations (see Section 11).		AES is ubiquitous in Kerberos implementations (see Section 11).
	The last sentence of the paragraph on RC4 (called "arcfour"		The last sentence of the paragraph on RC4 (called "arcfour"
	in [RFC4253]) in Section 6.3 of [RFC4253] should read: "Arcfour (and		in [RFC4253]) in Section 6.3 of [RFC4253] should read: "Arcfour (and
	RC4) are extremely weak [RFC6649] [RFC7457] [RFCxxxx] [RFCyyyy] and		RC4) are extremely weak [RFC6649] [RFC7457] [RFCxxxx] [RFCyyyy] and
	therefore their use is NOT RECOMMENDED."		therefore their use is NOT RECOMMENDED."
	References to RFC 6649, RFC 7457, RFC xxxx and this document (the		References to RFC 6649, RFC 7457, RFC xxxx and this document (the
	reference to this document is RFCyyyy in the above paragraph) should		reference to this document is RFCyyyy in the above paragraph) should
	be added to Section 6.3 of [RFC4253].		be added to Section 6.3 of [RFC4253].
	5. Updates to RFC 6649		5. Updates to RFC 6649
	RFC 6649, also known as BCP 179, deprecates DES, RC4-HMAC-EXP and		RFC 6649, also known as BCP 179, depreciates DES, RC4-HMAC-EXP and
	other weak cryptography in Kerberos. It is updated to note the		other weak cryptography in Kerberos. It is updated to note the
	deprecation of rc4-hmac and the deprecation of RC4 in all IETF		deprecation of rc4-hmac and the deprecation of RC4 in all IETF
	protocols.		protocols.
	The security considerations of [RFC6649] (Section 6 of [RFC6649])		The security considerations of [RFC6649] (Section 6 of [RFC6649])
	read, in their last paragraph:		read, in their last paragraph:
	"""		"""
	The security considerations of [RFC4757] continue to apply to		The security considerations of [RFC4757] continue to apply to
	RC4-HMAC, including the known weaknesses of RC4 and MD4, and this		RC4-HMAC, including the known weaknesses of RC4 and MD4, and this
	document does not change the Informational status of [RFC4757] for		document does not change the Informational status of [RFC4757] for
	skipping to change at page 4, line 43 ¶		skipping to change at page 4, line 43 ¶
	Section 13.1 of [RFC6733] required that clients implement two RC4		Section 13.1 of [RFC6733] required that clients implement two RC4
	cipher suites and a 3DES cipher suite (but recommends implementing an		cipher suites and a 3DES cipher suite (but recommends implementing an
	AES cipher suite).		AES cipher suite).
	RFC 6733 was published in October 2012, and all paragraphs but the		RFC 6733 was published in October 2012, and all paragraphs but the
	last of Section 13.1 of [RFC6733] are to be replaced with:		last of Section 13.1 of [RFC6733] are to be replaced with:
	"""		"""
	Diameter nodes were formerly required to implement insecure RC4		Diameter nodes were formerly required to implement insecure RC4
	cipher suites and weak 3DES cipher suites. RC4 MUST NOT be used		cipher suites and weak 3DES cipher suites. RC4 MUST NOT be used
	because it is prohibited by RFC 7465.		because it is prohibited by RFC 7465.
	Diameter nodes MUST comply to [RFC7525].		Diameter nodes MUST comply to [RFC7525].
	TLS_RSA_WITH_AES_128_CBC_SHA was not chosen to be absolutely required		TLS_RSA_WITH_AES_128_CBC_SHA was not chosen to be absolutely required
	as Diameter nodes may require all connections to use forward secrecy		as Diameter nodes may require all connections to use forward secrecy
	by only implementing cipher suites with forward secrecy.		by only implementing cipher suites with forward secrecy.
	TLS_RSA_WITH_AES_128_CBC_SHA is not a forward secrecy cipher suite		TLS_RSA_WITH_AES_128_CBC_SHA is not a forward secrecy cipher suite
	because all connections can be decrypted once the private RSA key is		because all connections can be decrypted once the private RSA key is
	known by an attacker.		known by an attacker.
	skipping to change at page 5, line 26 ¶		skipping to change at page 5, line 26 ¶
	(for example, using "NOT RECOMMENDED" or "SHOULD NOT").		(for example, using "NOT RECOMMENDED" or "SHOULD NOT").
	8. IANA Considerations		8. IANA Considerations
	IANA may need to take action as the status for RC4 and 3DES		IANA may need to take action as the status for RC4 and 3DES
	algorithms for Secure Shell (SSH) is changed by this document		algorithms for Secure Shell (SSH) is changed by this document
	(see Section 6, that updates [RFC4253]).		(see Section 6, that updates [RFC4253]).
	9. Security Considerations		9. Security Considerations
	This document deprecates RC4, that is obsolete cryptography, and		This document depreciates RC4, that is obsolete cryptography, and
	several attacks that render it useless have been published [RFC6649].		several attacks that render it useless have been published [RFC6649].
	Refer to Section 5 of [RFCxxxx] for further security considerations.		Refer to Section 5 of [RFCxxxx] for further security considerations.
	10. Acknowledgements		10. Acknowledgements
	[[RFC-Editor: When possible, add native names according to the		[[RFC-Editor: When possible, add native names according to the
	conventions of RFC 7997.]]		conventions of RFC 7997.]]
	Thanks to the following people:		Thanks to the following people:
	* Sean Turner and Lily Chen for writing RFC 6151, that contains		* Sean Turner and Lily Chen for writing RFC 6151, that contains
	updated security considerations for MD5 and HMAC-MD5.		updated security considerations for MD5 and HMAC-MD5.
	* Love Hornquist Astrand and Tom Yu for writing RFC 6649, that		* Love Hornquist Astrand and Tom Yu for writing RFC 6649, that
	deprecates weak cryptographic algorithms in Kerberos.		depreciates weak cryptographic algorithms in Kerberos.
	* Yaron Sheffer, Ralph Holz and Peter Saint-Andre for writing		* Yaron Sheffer, Ralph Holz and Peter Saint-Andre for writing
	RFC 7457, that summarises known attacks against Transport Layer		RFC 7457, that summarises known attacks against Transport Layer
	Security (TLS), and RFC 7525, that provides recommendations for		Security (TLS), and RFC 7525, that provides recommendations for
	the use of TLS and Datagram Transport Layer Security (DTLS).		the use of TLS and Datagram Transport Layer Security (DTLS).
	* Andrei Popov for writing RFC 7465, that prohibits RC4 cipher		* Andrei Popov for writing RFC 7465, that prohibits RC4 cipher
	suites in Transport Layer Security (TLS).		suites in Transport Layer Security (TLS).
	* Julien Elie for sending me an email about the requirements to		* Julien Elie for sending me an email about the requirements to
	implement RC4 cipher suites in RFC 3501 and RFC 6733.		implement RC4 cipher suites in RFC 3501 and RFC 6733.
	Also thanks to SSL Labs for capping server grades to B (RC4 only used
	with older protocols) and C (RC4 used with modern protocols) when
	servers support RC4, and flagging cipher suites and clients using RC4
	with a red colour (for INSECURE and RC4). You can test any server at
	<https://www.ssllabs.com/ssltest/>.
	Refer to the acknowledgements section of RFC 6649, RFC 7457 and		Refer to the acknowledgements section of RFC 6649, RFC 7457 and
	RFC xxxx for further acknowledgements.		RFC xxxx for further acknowledgements.
	11. References		11. References
	11.1. Normative References		11.1. 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, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	skipping to change at page 6, line 34 ¶		skipping to change at page 6, line 28 ¶
	[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,		[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
	"Recommendations for Secure Use of Transport Layer		"Recommendations for Secure Use of Transport Layer
	Security (TLS) and Datagram Transport Layer Security		Security (TLS) and Datagram Transport Layer Security
	(DTLS)", BCP 195, RFC 7525, May 2015.		(DTLS)", BCP 195, RFC 7525, May 2015.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in
	RFC 2119 Key Words", BCP 14, RFC 8174, May 2017.		RFC 2119 Key Words", BCP 14, RFC 8174, May 2017.
	[RFCxxxx] Kaduk, B., and M. Short, "Deprecate 3DES and RC4 in		[RFCxxxx] Kaduk, B., and M. Short, "Deprecate 3DES and RC4 in
	Kerberos", draft-ietf-curdle-des-des-des-die-die-die-04,		Kerberos", draft-ietf-curdle-des-des-des-die-die-die-05,
	Work in Progress.		Work in Progress.
	11.2. Informative References		11.2. Informative References
	[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - Version		[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - Version
	4rev1", RFC 3501, March 2003.		4rev1", RFC 3501, March 2003.
	[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, January 2006.		Transport Layer Protocol", RFC 4253, January 2006.
	skipping to change at page 8, line 9 ¶		skipping to change at page 8, line 9 ¶
	12. Author's Address		12. Author's Address
	Luis Camara		Luis Camara
	EMail: <luis.camara@live.com.pt>		EMail: <luis.camara@live.com.pt>
	Appendix A. Changelog		Appendix A. Changelog
	[[RFC-Editor: please remove this section when publishing.]]		[[RFC-Editor: please remove this section when publishing.]]
	WG draft (draft-ietf-curdle-rc4-die-die-die):		WG draft:
	02 - addressed Todd Short's concerns.		03 - Style changes, removed SSL Labs paragraph in the
			acknowledgements section and updated RFCxxxx reference to v05.
			Now British English is used in all parts of the document,
			except quotations.
	01 - massive simplification: removed informational updates, removed		02 - Addressed Todd Short's concerns.
			01 - Massive simplification: removed informational updates, removed
	all Pre-5378 Material, retracted all "Obsoletes:" except for		all Pre-5378 Material, retracted all "Obsoletes:" except for
	RFC 4345, removed Appendix A and renamed changelog to Appendix A.		RFC 4345, removed Appendix A and renamed changelog to Appendix A.
	00 - dummy update to get the draft into the curdle WG.		00 - Dummy update to get the draft into the curdle WG.
	Individual draft (draft-luis140219-curdle-rc4-die-die-die):		Individual draft:
	02 - changed title to "Deprecating RC4 in all IETF Protocols", changed		02 - Changed title to "Deprecating RC4 in all IETF Protocols", changed
	the header of all pages to "Deprecating RC4 in all Protocols",		the header of all pages to "Deprecating RC4 in all Protocols",
	updated RFC 3501 and RFC 6733, simplified the reference to		updated RFC 3501 and RFC 6733, simplified the reference to
	draft-ietf-curdle-des-des-des-die-die-die to a simple "Work in		draft-ietf-curdle-des-des-des-die-die-die to a simple "Work in
	Progress" reference and fixed typos.		Progress" reference and fixed typos.
	01 - explained reasons for updating RFC 7905 and added an informative		01 - Explained reasons for updating RFC 7905 and added an informative
	reference to RFC 4757 to take away a missing reference warning.		reference to RFC 4757 to take away a missing reference warning.
	00 - first version. [RFCxxxx] is a reference to		00 - First version. [RFCxxxx] is a reference to
	draft-ietf-curdle-des-des-des-die-die-die. The quote in		draft-ietf-curdle-des-des-des-die-die-die. The quote in
	Section 11 is from version 03 of this draft (posted 2017-06-15)		Section 11 is from version 03 of this draft (posted 2017-06-15)
End of changes. 22 change blocks.
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