draft-ietf-uta-tls-attacks-01.txt		draft-ietf-uta-tls-attacks-02.txt
	uta Y. Sheffer		uta Y. Sheffer
	Internet-Draft Porticor		Internet-Draft Porticor
	Intended status: Informational R. Holz		Intended status: Informational R. Holz
	Expires: December 26, 2014 TUM		Expires: February 13, 2015 TUM
	P. Saint-Andre		P. Saint-Andre
	&yet		&yet
	June 24, 2014		August 12, 2014
	Summarizing Current Attacks on TLS and DTLS		Summarizing Current Attacks on TLS and DTLS
	draft-ietf-uta-tls-attacks-01		draft-ietf-uta-tls-attacks-02
	Abstract		Abstract
	Over the last few years there have been several serious attacks on		Over the last few years there have been several serious attacks on
	TLS, including attacks on its most commonly used ciphers and modes of		TLS, including attacks on its most commonly used ciphers and modes of
	operation. This document summarizes these attacks, with the goal of		operation. This document summarizes these attacks, with the goal of
	motivating generic and protocol-specific recommendations on the usage		motivating generic and protocol-specific recommendations on the usage
	of TLS and DTLS.		of TLS and DTLS.
	Status of This Memo		Status of This Memo
	skipping to change at page 1, line 37		skipping to change at page 1, line 37
	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 December 26, 2014.		This Internet-Draft will expire on February 13, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 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 18		skipping to change at page 2, line 18
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Attacks on TLS . . . . . . . . . . . . . . . . . . . . . . . 3		2. Attacks on TLS . . . . . . . . . . . . . . . . . . . . . . . 3
	2.1. SSL Stripping . . . . . . . . . . . . . . . . . . . . . . . 3		2.1. SSL Stripping . . . . . . . . . . . . . . . . . . . . . . . 3
	2.2. BEAST . . . . . . . . . . . . . . . . . . . . . . . . . . . 3		2.2. BEAST . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2.3. Lucky Thirteen . . . . . . . . . . . . . . . . . . . . . . 3		2.3. Lucky Thirteen . . . . . . . . . . . . . . . . . . . . . . 3
	2.4. Attacks on RC4 . . . . . . . . . . . . . . . . . . . . . . 3		2.4. Attacks on RC4 . . . . . . . . . . . . . . . . . . . . . . 3
	2.5. Compression Attacks: CRIME and BREACH . . . . . . . . . . . 4		2.5. Compression Attacks: CRIME and BREACH . . . . . . . . . . . 4
	2.6. Certificate Attacks . . . . . . . . . . . . . . . . . . . . 4		2.6. Certificate Attacks . . . . . . . . . . . . . . . . . . . . 4
	2.7. Diffe-Hellman Parameters . . . . . . . . . . . . . . . . . 4		2.7. Diffie-Hellman Parameters . . . . . . . . . . . . . . . . . 4
	2.8. Denial of Service . . . . . . . . . . . . . . . . . . . . . 4		2.8. Renegotiation . . . . . . . . . . . . . . . . . . . . . . . 5
	3. Security Considerations . . . . . . . . . . . . . . . . . . . 5		2.9. Triple Hanshake . . . . . . . . . . . . . . . . . . . . . . 5
	4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5		2.10. Denial of Service . . . . . . . . . . . . . . . . . . . . . 5
	5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5		2.11. Implementation Issues . . . . . . . . . . . . . . . . . . . 5
	6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5		3. Applicability to DTLS . . . . . . . . . . . . . . . . . . . . 6
	6.1. Normative References . . . . . . . . . . . . . . . . . . . 5		4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
	6.2. Informative References . . . . . . . . . . . . . . . . . . 5		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
	Appendix A. Appendix: Change Log . . . . . . . . . . . . . . . . 7		6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
	A.1. draft-ietf-uta-tls-bcp-01 . . . . . . . . . . . . . . . . . 7		7. Informative References . . . . . . . . . . . . . . . . . . . 6
	A.2. draft-ietf-uta-tls-bcp-00 . . . . . . . . . . . . . . . . . 7		Appendix A. Appendix: Change Log . . . . . . . . . . . . . . . . 9
	A.3. draft-sheffer-uta-tls-bcp-00 . . . . . . . . . . . . . . . 7		A.1. draft-ietf-uta-tls-attacks-02 . . . . . . . . . . . . . . . 9
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8		A.2. draft-ietf-uta-tls-attacks-01 . . . . . . . . . . . . . . . 9
			A.3. draft-ietf-uta-tls-attacks-00 . . . . . . . . . . . . . . . 9
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
	1. Introduction		1. Introduction
	Over the last few years there have been several major attacks on TLS		Over the last few years there have been several major attacks on TLS
	[RFC5246], including attacks on its most commonly used ciphers and		[RFC5246], including attacks on its most commonly used ciphers and
	modes of operation. Details are given in Section 2, but suffice it		modes of operation. Details are given in Section 2, but suffice it
	to say that both AES-CBC and RC4, which together make up for most		to say that both AES-CBC and RC4, which together make up for most
	current usage, have been seriously attacked in the context of TLS.		current usage, have been seriously attacked in the context of TLS.
	This situation motivated the creation of the UTA working group, which		This situation motivated the creation of the UTA working group, which
	is tasked with the creation of generic and protocol-specific		is tasked with the creation of generic and protocol-specific
	recommendation for the use of TLS and DTLS.		recommendations for the use of TLS and DTLS.
	"Attacks always get better; they never get worse" (ironically, this		"Attacks always get better; they never get worse" (ironically, this
	saying is attributed to the NSA). This list of attacks describes our		saying is attributed to the NSA). This list of attacks describes our
	knowledge as of this writing. It seems likely that new attacks will		knowledge as of this writing. It seems likely that new attacks will
	be invented in the future.		be invented in the future.
	For a more detailed discussion of the attacks listed here, the		For a more detailed discussion of the attacks listed here, the
	interested reader is referred to [Attacks-iSec].		interested reader is referred to [Attacks-iSec].
	2. Attacks on TLS		2. Attacks on TLS
	skipping to change at page 3, line 18		skipping to change at page 3, line 21
	recommendations. This is not intended to be an extensive survey of		recommendations. This is not intended to be an extensive survey of
	TLS's security.		TLS's security.
	While there are widely deployed mitigations for some of the attacks		While there are widely deployed mitigations for some of the attacks
	listed below, we believe that their root causes necessitate a more		listed below, we believe that their root causes necessitate a more
	systemic solution.		systemic solution.
	2.1. SSL Stripping		2.1. SSL Stripping
	Various attacks attempt to remove the use of SSL/TLS altogether, by		Various attacks attempt to remove the use of SSL/TLS altogether, by
	modifying HTTP traffic and HTML pages as they pass on the wire.		modifying unencrypted protocols that request the use of TLS,
	These attacks are known collectively as SSL Stripping, and were first		specifically modifying HTTP traffic and HTML pages as they pass on
	introduced by Moxie Marlinspike [SSL-Stripping]. In the context of		the wire. These attacks are known collectively as SSL Stripping, and
	Web traffic, these attacks are only effective if the client accesses		were first introduced by Moxie Marlinspike [SSL-Stripping]. In the
	a Web server using a mixture of HTTP and HTTPS.		context of Web traffic, these attacks are only effective if the
			client accesses a Web server using a mixture of HTTP and HTTPS.
	2.2. BEAST		2.2. BEAST
	The BEAST attack [BEAST] uses issues with the TLS 1.0 implementation		The BEAST attack [BEAST] uses issues with the TLS 1.0 implementation
	of CBC (that is, the predictable initialization vector) to decrypt		of CBC (that is, the predictable initialization vector) to decrypt
	parts of a packet, and specifically to decrypt HTTP cookies when HTTP		parts of a packet, and specifically to decrypt HTTP cookies when HTTP
	is run over TLS.		is run over TLS.
	2.3. Lucky Thirteen		2.3. Lucky Thirteen
	A consequence of the MAC-then-encrypt design in all current versions		A consequence of the MAC-then-encrypt design in all current versions
	of TLS is the existence of padding oracle attacks [Padding-Oracle].		of TLS is the existence of padding oracle attacks [Padding-Oracle].
	A recent incarnation of these attacks is the Lucky Thirteen attack		A recent incarnation of these attacks is the Lucky Thirteen attack
	[CBC-Attack], a timing side-channel attack that allows the attacker		[CBC-Attack], a timing side-channel attack that allows the attacker
	to decrypt arbitrary ciphertext.		to decrypt arbitrary ciphertext.
			The Lucky Thirteen attack can be mitigated by using authenticated
			encryption like AES-GCM [RFC5288] and encrypt-then-mac
			[I-D.ietf-tls-encrypt-then-mac] instead of the TLS default of MAC-
			then-encrypt.
	2.4. Attacks on RC4		2.4. Attacks on RC4
	The RC4 algorithm [RC4] has been used with TLS (and previously, SSL)		The RC4 algorithm [RC4] has been used with TLS (and previously, SSL)
	for many years. RC4 has long been known to have a variety of		for many years. RC4 has long been known to have a variety of
	cryptographic weaknesses, e.g. [RC4-Attack-Pau], [RC4-Attack-Man],		cryptographic weaknesses, e.g. [RC4-Attack-Pau], [RC4-Attack-Man],
	[RC4-Attack-FMS]. Recent cryptanalysis results [RC4-Attack-AlF]		[RC4-Attack-FMS]. Recent cryptanalysis results [RC4-Attack-AlF]
	exploit biases in the RC4 keystream to recover repeatedly encrypted		exploit biases in the RC4 keystream to recover repeatedly encrypted
	plaintexts.		plaintexts.
	These recent results are on the verge of becoming practically		These recent results are on the verge of becoming practically
	exploitable; currently they require 2^26 sessions or 13x2^30		exploitable; currently they require 2^26 sessions or 13x2^30
	encryptions. As a result, RC4 can no longer be seen as providing a		encryptions. As a result, RC4 can no longer be seen as providing a
	sufficient level of security for TLS sessions.		sufficient level of security for TLS sessions. For further details,
			the reader is refered to [I-D.ietf-tls-prohibiting-rc4].
	2.5. Compression Attacks: CRIME and BREACH		2.5. Compression Attacks: CRIME and BREACH
	The CRIME attack [CRIME] allows an active attacker to decrypt		The CRIME attack [CRIME] allows an active attacker to decrypt
	ciphertext (specifically, cookies) when TLS is used with protocol-		ciphertext (specifically, cookies) when TLS is used with TLS level
	level compression.		compression.
	The TIME attack [TIME] and the later BREACH attack [BREACH] both make		The TIME attack [TIME] and the later BREACH attack [BREACH] both make
	similar use of HTTP-level compression to decrypt secret data passed		similar use of HTTP-level compression to decrypt secret data passed
	in the HTTP response. We note that compression of the HTTP message		in the HTTP response. We note that compression of the HTTP message
	body is much more prevalent than compression at the TLS level.		body is much more prevalent than compression at the TLS level.
	The former attack can be mitigated by disabling TLS compression, as		The former attack can be mitigated by disabling TLS compression. We
	recommended below. We are not aware of mitigations at the protocol		are not aware of mitigations at the TLS protocol level to the latter
	level to the latter attack, and so application-level mitigations are		attack, and so application-level mitigations are needed (see
	needed (see [BREACH]). For example, implementations of HTTP that use		[BREACH]). For example, implementations of HTTP that use CSRF tokens
	CSRF tokens will need to randomize them even when the recommendations		will need to randomize them even when the recommendations of
	of [I-D.ietf-uta-tls-bcp] are adopted.		[I-D.ietf-uta-tls-bcp] are adopted.
	2.6. Certificate Attacks		2.6. Certificate Attacks
	There have been several practical attacks on TLS when used with RSA		There have been several practical attacks on TLS when used with RSA
	certificates (the most common use case). These include		certificates (the most common use case). These include
	[Bleichenbacher98] and [Klima03]. While the Bleichenbacher attack		[Bleichenbacher98] and [Klima03]. While the Bleichenbacher attack
	has been mitigated in TLS 1.0, the Klima attack that relies on a		has been mitigated in TLS 1.0, the Klima attack that relies on a
	version-check oracle is only mitigated by TLS 1.1.		version-check oracle is only mitigated by TLS 1.1.
	The use of RSA certificates often involves exploitable timing issues		The use of RSA certificates often involves exploitable timing issues
	[Brumley03], unless the implementation takes care to explicitly		[Brumley03], unless the implementation takes care to explicitly
	eliminate them.		eliminate them.
	2.7. Diffe-Hellman Parameters		2.7. Diffie-Hellman Parameters
	TLS allows to define ephemeral Diffie-Hellman and Elliptic Curve		TLS allows to define ephemeral Diffie-Hellman and Elliptic Curve
	Diffie-Hellman parameters in its respective key exchange modes. This		Diffie-Hellman parameters in its respective key exchange modes. This
	results in an outstanding attack, detailed in [Cross-Protocol]. In		results in an outstanding attack, detailed in [Cross-Protocol]. In
	addition, clients that do not properly verify the received parameters		addition, clients that do not properly verify the received parameters
	are exposed to MITM attacks. Unfortunately the TLS protocol does not		are exposed to man in the middle (MITM) attacks. Unfortunately the
	require this verification, see [RFC6989] for the IPsec analogy.		TLS protocol does not require this verification, see [RFC6989] for
			the IPsec analogy.
	2.8. Denial of Service		2.8. Renegotiation
			A major attack on the TLS renegotiation mechanism applies to all
			current versions of the protocol. The attack and the TLS extension
			that resolves it are described in [RFC5746].
			2.9. Triple Hanshake
			The triple handshake attack [[TRIPLE-HS, add the reference when
			published]] enables the attacker to cause two TLS connections to
			share keying material. This leads to a multitude of attacks, e.g.
			Man-in-the-Middle, breaking safe renegotiation and breaking channel
			binding via TLS Exporter [RFC5705] or "tls-unique" [RFC5929].
			2.10. Denial of Service
	Server CPU power has progressed over the years so that TLS can now be		Server CPU power has progressed over the years so that TLS can now be
	turned on by default. However the risk of malicious clients and		turned on by default. However the risk of malicious clients and
	coordinated groups of clients ("botnets") mounting denial of service		coordinated groups of clients ("botnets") mounting denial of service
	attacks is still very real. TLS adds another vector for		attacks is still very real. TLS adds another vector for
	computational attacks, since a client can easily (with little		computational attacks, since a client can easily (with little
	computational effort) force the server to expend relatively large		computational effort) force the server to expend relatively large
	computational work. It is known that such attacks have in fact been		computational work. It is known that such attacks have in fact been
	mounted.		mounted.
	3. Security Considerations		2.11. Implementation Issues
			Even when the protocol is fully specified, the are very common issues
			that often plague implementations. In particular, the integration of
			higher-level protocols, TLS and its PKI-based authentication is the
			source of misunderstandings and implementation "shortcuts". An
			extensive survey of these issues can be found in [Georgiev2012].
			o Implementations may omit validation of the server certificate
			altogether. For example, this is true of the default
			implementation of HTTP client libraries in Python 2.
			o Implementations may not validate the server identity. This
			validation typically amounts to matching the protocol-level server
			name with the certificate's Subject Alternative Name field.
			o Implementations may be validating the certificate chain
			incorrectly or not at all, or using an incorrect or outdated trust
			anchor list.
			3. Applicability to DTLS
			DTLS [RFC4347] [RFC6347] is an adaptation of TLS for UDP datagrams.
			With respect to the attacks described in the current document, DTLS
			1.0 is equivalent to TLS 1.1. The only exception is RC4 which is
			disallowed in DTLS. DTLS 1.2 is equivalent to TLS 1.2.
			4. Security Considerations
	This document describes protocol attacks in an informational manner,		This document describes protocol attacks in an informational manner,
	and in itself does not have any security implications. Its companion		and in itself does not have any security implications. Its companion
	documents certainly do.		documents certainly do.
	4. IANA Considerations		5. IANA Considerations
	This document requires no IANA actions.		This document requires no IANA actions. [Note to RFC Editor: please
			remove this whole section before publication.]
	5. Acknowledgements		6. Acknowledgments
	We would like to thank Stephen Farrell, Simon Josefsson, Yoav Nir,		We would like to thank Stephen Farrell, Simon Josefsson, John
	Kenny Paterson, Patrick Pelletier, Tom Ritter and Rich Salz for their		Mattsson, Yoav Nir, Kenny Paterson, Patrick Pelletier, Tom Ritter and
	review of this document. We thank Andrei Popov for contributing text		Rich Salz for their review of this document. We thank Andrei Popov
	on RC4.		for contributing text on RC4, Kohei Kasamatsu for text on Lucky13,
			Ilari Liusvaara for text on attacks and on DTLS.
	The document was prepared using the lyx2rfc tool, created by Nico		The document was prepared using the lyx2rfc tool, created by Nico
	Williams.		Williams.
	6. References		7. Informative References
	6.1. Normative References		[RFC4347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
			Security", RFC 4347, April 2006.
	[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security		[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
	(TLS) Protocol Version 1.2", RFC 5246, August 2008.		(TLS) Protocol Version 1.2", RFC 5246, August 2008.
	6.2. Informative References		[RFC5288] Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
			Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
			August 2008.
	[I-D.ietf-uta-tls-bcp]		[RFC5705] Rescorla, E., "Keying Material Exporters for Transport
	Sheffer, Y., Holz, R., and P. Saint-Andre,		Layer Security (TLS)", RFC 5705, March 2010.
	"Recommendations for Secure Use of TLS and DTLS", draft-
	ietf-uta-tls-bcp-00 (work in progress), March 2014.		[RFC5746] Rescorla, E., Ray, M., Dispensa, S., and N. Oskov,
			"Transport Layer Security (TLS) Renegotiation Indication
			Extension", RFC 5746, February 2010.
			[RFC5929] Altman, J., Williams, N., and L. Zhu, "Channel Bindings
			for TLS", RFC 5929, July 2010.
			[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
			Security Version 1.2", RFC 6347, January 2012.
	[RFC6989] Sheffer, Y. and S. Fluhrer, "Additional Diffie-Hellman		[RFC6989] Sheffer, Y. and S. Fluhrer, "Additional Diffie-Hellman
	Tests for the Internet Key Exchange Protocol Version 2		Tests for the Internet Key Exchange Protocol Version 2
	(IKEv2)", RFC 6989, July 2013.		(IKEv2)", RFC 6989, July 2013.
			[I-D.ietf-uta-tls-bcp]
			Sheffer, Y., Holz, R., and P. Saint-Andre,
			"Recommendations for Secure Use of TLS and DTLS", draft-
			ietf-uta-tls-bcp-01 (work in progress), June 2014.
			[I-D.ietf-tls-prohibiting-rc4]
			Popov, A., "Prohibiting RC4 Cipher Suites", draft-ietf-
			tls-prohibiting-rc4-00 (work in progress), July 2014.
			[I-D.ietf-tls-encrypt-then-mac]
			Gutmann, P., "Encrypt-then-MAC for TLS and DTLS", draft-
			ietf-tls-encrypt-then-mac-03 (work in progress), July
			2014.
	[CBC-Attack]		[CBC-Attack]
	AlFardan, N. and K. Paterson, "Lucky Thirteen: Breaking		AlFardan, N. and K. Paterson, "Lucky Thirteen: Breaking
	the TLS and DTLS Record Protocols", IEEE Symposium on		the TLS and DTLS Record Protocols", IEEE Symposium on
	Security and Privacy , 2013.		Security and Privacy , 2013.
	[BEAST] Rizzo, J. and T. Duong, "Browser Exploit Against SSL/TLS",		[BEAST] Rizzo, J. and T. Duong, "Browser Exploit Against SSL/TLS",
	2011, <http://packetstormsecurity.com/files/105499/		2011, <http://packetstormsecurity.com/files/105499/
	Browser-Exploit-Against-SSL-TLS.html>.		Browser-Exploit-Against-SSL-TLS.html>.
	[CRIME] Rizzo, J. and T. Duong, "The CRIME Attack", EKOparty		[CRIME] Rizzo, J. and T. Duong, "The CRIME Attack", EKOparty
	skipping to change at page 6, line 34		skipping to change at page 8, line 16
	Fluhrer, S., Mantin, I., and A. Shamir, "Weaknesses in the		Fluhrer, S., Mantin, I., and A. Shamir, "Weaknesses in the
	Key Scheduling Algorithm of RC4", Selected Areas in		Key Scheduling Algorithm of RC4", Selected Areas in
	Cryptography , 2001.		Cryptography , 2001.
	[RC4-Attack-AlF]		[RC4-Attack-AlF]
	AlFardan, N., Bernstein, D., Paterson, K., Poettering, B.,		AlFardan, N., Bernstein, D., Paterson, K., Poettering, B.,
	and J. Schuldt, "On the Security of RC4 in TLS", Usenix		and J. Schuldt, "On the Security of RC4 in TLS", Usenix
	Security Symposium 2013, 2013, <https://www.usenix.org/		Security Symposium 2013, 2013, <https://www.usenix.org/
	conference/usenixsecurity13/security-rc4-tls>.		conference/usenixsecurity13/security-rc4-tls>.
			[Georgiev2012]
			Georgiev, M., Iyengar, S., Jana, S., Anubhai, R., Boneh,
			D., and V. Shmatikov, "The most dangerous code in the
			world: validating SSL certificates in non-browser
			software", 2012,
			<http://doi.acm.org/10.1145/2382196.2382204>.
	[Attacks-iSec]		[Attacks-iSec]
	Sarkar, P. and S. Fitzgerald, "Attacks on SSL, a		Sarkar, P. and S. Fitzgerald, "Attacks on SSL, a
	comprehensive study of BEAST, CRIME, TIME, BREACH, Lucky13		comprehensive study of BEAST, CRIME, TIME, BREACH, Lucky13
	and RC4 biases", 8 2013, <https://www.isecpartners.com/		and RC4 biases", 8 2013, <https://www.isecpartners.com/
	media/106031/ssl_attacks_survey.pdf>.		media/106031/ssl_attacks_survey.pdf>.
	[Padding-Oracle]		[Padding-Oracle]
	Vaudenay, S., "Security Flaws Induced by CBC Padding		Vaudenay, S., "Security Flaws Induced by CBC Padding
	Applications to SSL, IPSEC, WTLS...", EUROCRYPT 2002,		Applications to SSL, IPSEC, WTLS...", EUROCRYPT 2002,
	2002, <http://www.iacr.org/cryptodb/archive/2002/		2002, <http://www.iacr.org/cryptodb/archive/2002/
	skipping to change at page 7, line 35		skipping to change at page 9, line 21
	sessions in SSL/TLS", 2003.		sessions in SSL/TLS", 2003.
	[Brumley03]		[Brumley03]
	Brumley, D. and D. Boneh, "Remote timing attacks are		Brumley, D. and D. Boneh, "Remote timing attacks are
	practical", 2003.		practical", 2003.
	Appendix A. Appendix: Change Log		Appendix A. Appendix: Change Log
	Note to RFC Editor: please remove this section before publication.		Note to RFC Editor: please remove this section before publication.
	A.1. draft-ietf-uta-tls-bcp-01		A.1. draft-ietf-uta-tls-attacks-02
			o Added implementation issues ("most dangerous code"),
			renegotiation, triple handshake.
			o Added text re: mitigation of Lucky13.
			o Added applicability to DTLS.
			A.2. draft-ietf-uta-tls-attacks-01
	o Added SSL Stripping, attacks related to certificates, Diffie		o Added SSL Stripping, attacks related to certificates, Diffie
	Hellman parameters and denial of service.		Hellman parameters and denial of service.
	o Expanded on RC4 attacks, thanks to Andrei Popov.		o Expanded on RC4 attacks, thanks to Andrei Popov.
	A.2. draft-ietf-uta-tls-bcp-00		A.3. draft-ietf-uta-tls-attacks-00
	o Initial WG version, with only updated references.
	A.3. draft-sheffer-uta-tls-bcp-00
	o Initial version, extracted from draft-sheffer-tls-bcp-01.		o Initial version, extracted from draft-sheffer-tls-bcp-01.
	Authors' Addresses		Authors' Addresses
	Yaron Sheffer		Yaron Sheffer
	Porticor		Porticor
	29 HaHarash St.		29 HaHarash St.
	Hod HaSharon 4501303		Hod HaSharon 4501303
	Israel		Israel
End of changes. 28 change blocks.
	57 lines changed or deleted		149 lines changed or added
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