Updates to the Cipher Suites in Secure Syslog
draft-ietf-uta-ciphersuites-in-sec-syslog-07
The information below is for an old version of the document that is already published as an RFC.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 9662.
|
|
|---|---|---|---|
| Authors | Chris M. Lonvick , Sean Turner , Joseph A. Salowey | ||
| Last updated | 2024-10-07 (Latest revision 2024-07-24) | ||
| Replaces | draft-ciphersuites-in-sec-syslog | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Associated WG milestone |
|
||
| Document shepherd | Kent Watsen | ||
| Shepherd write-up | Show Last changed 2024-02-29 | ||
| IESG | IESG state | Became RFC 9662 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | Francesca Palombini | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | No IANA Actions |
draft-ietf-uta-ciphersuites-in-sec-syslog-07
Internet Engineering Task Force C. Lonvick
Internet-Draft
Updates: 5425 6012 (if approved) S. Turner
Intended status: Standards Track sn3rd
Expires: 25 January 2025 J. Salowey
Venafi
24 July 2024
Updates to the Cipher Suites in Secure Syslog
draft-ietf-uta-ciphersuites-in-sec-syslog-07
Abstract
The IETF published two specifications, namely RFC 5425 and RFC 6012,
for securing the Syslog protocol using TLS and DTLS, respectively.
This document updates the cipher suites in RFC 5425, Transport Layer
Security (TLS) Transport Mapping for Syslog, and RFC 6012, Datagram
Transport Layer Security (DTLS) Transport Mapping for Syslog. It
also updates the transport protocol in RFC 6012.
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 https://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 25 January 2025.
Copyright Notice
Copyright (c) 2024 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 (https://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
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and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Support for Updating . . . . . . . . . . . . . . . . . . . . 3
4. Updates to RFC 5425 . . . . . . . . . . . . . . . . . . . . . 4
5. Updates to RFC 6012 . . . . . . . . . . . . . . . . . . . . . 4
6. Early Data . . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Authors Notes . . . . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
10. Security Considerations . . . . . . . . . . . . . . . . . . . 6
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
11.1. Normative References . . . . . . . . . . . . . . . . . . 6
11.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The IETF published RFC 5425, Transport Layer Security (TLS) Transport
Mapping for Syslog, and RFC 6012, Datagram Transport Layer Security
(DTLS) Transport Mapping for Syslog.
Both specifications, [RFC5425] and [RFC6012], require the use of RSA-
based certificates and the use of TLS/DTLS versions that are not the
most recent.
[RFC5425] requires that implementations "MUST" support TLS 1.2
[RFC5246] and are "REQUIRED" to support the mandatory to implement
cipher suite TLS_RSA_WITH_AES_128_CBC_SHA (Section 4.2).
[RFC6012] requires that implementations "MUST" support DTLS 1.0
[RFC4347] and are also "REQUIRED" to support the mandatory to
implement cipher suite TLS_RSA_WITH_AES_128_CBC_SHA (Section 5.2).
The community is moving away from cipher suits that don't offer
forward secrecy and towards more robust suites.
The DTLS 1.0 transport [RFC4347] has been deprecated by [BCP195] and
the community is moving to DTLS 1.2 [RFC6347] and DTLS 1.3 [RFC9147].
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This document updates [RFC5425] and [RFC6012] to prefer the use of
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 over the use of
TLS_RSA_WITH_AES_128_CBC_SHA.
This document also updates [RFC6012] to make a recommendation of a
mandatory to implement secure datagram transport.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "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.
3. Support for Updating
[draft-ietf-tls-rfc8447bis-09] generally reminds us that
cryptographic algorithms and parameters will be broken or weakened
over time. Blindly implementing the cryptographic algorithms listed
in any specification is not advised. Implementers and users need to
check that the cryptographic algorithms specified continue to provide
the expected level of security.
As the Syslog Working Group determined, Syslog clients and servers
MUST use certificates as defined in [RFC5280]. Since both [RFC5425]
and [RFC6012] REQUIRED the use of TLS_RSA_WITH_AES_128_CBC_SHA, it is
very likely that RSA certificates have been implemented in devices
adhering to those specifications. [BCP195] notes that ECDHE cipher
suites exist for both RSA and ECDSA certificates, so moving to an
ECDHE cipher suite will not require replacing or moving away from any
currently installed RSA-based certificates.
[draft-ietf-tls-deprecate-obsolete-kex-04] documents that the cipher
suite TLS_RSA_WITH_AES_128_CBC_SHA, along with some other cipher
suites, may require mitigation techniques to achieve expected
security, which may be difficult to effectively implement. Along
those lines, [BCP195] [RFC9325] notes that
TLS_RSA_WITH_AES_128_CBC_SHA does not provide forward secrecy, a
feature that is highly desirable in securing event messages. That
document also goes on to recommend
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 as a cipher suite that does
provide forward secrecy.
As such, the community is moving away from algorithms that do not
provide forward secrecy. For example, the International
Electrotechnical Commission (IEC) has selected more robust suites
such as TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256, which is also listed
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as a currently RECCOMENDED algorithm in
[draft-ietf-tls-rfc8447bis-09] for their deployments of secure
syslog.
Additionally, [BCP195] [RFC8996] deprecates the use of DTLS 1.0
[RFC4347], which is the mandatory to implement transport protocol for
[RFC6012]. Therefore, the transport protocol for [RFC6012] must be
updated.
Finally, [BCP195] (RFC9325) provides guidance on the support of
[RFC8446] and [RFC9147].
Therefore, to maintain interoperability across implementations, the
mandatory to implement cipher suites listed in [RFC5425] and
[RFC6012] should be updated so that implementations of secure syslog
will still interoperate and provide an acceptable and expected level
of security.
However, since there are many implementations of syslog using the
cipher suites mandatated to be used in [RFC6012], a sudden change is
not desireable. To accomodate a migration path, this specification
will allow the use of both TLS_RSA_WITH_AES_128_CBC_SHA and
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 but REQUIRES that
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 be preferred.
4. Updates to RFC 5425
The mandatory to implement cipher suites are REQUIRED to be
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 and
TLS_RSA_WITH_AES_128_CBC_SHA.
Implementations of [RFC5425] SHOULD offer
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 but MAY offer
TLS_RSA_WITH_AES_128_CBC_SHA.
Implementations of [RFC5425] MUST continue to use TLS 1.2 [RFC5246]
as the mandatory to implement transport protocol.
As per [BCP195], implementations of [RFC5425] SHOULD support TLS 1.3
[RFC8446] and, if implemented, MUST prefer to negotiate TLS 1.3 over
earlier versions of TLS.
5. Updates to RFC 6012
The mandatory to implement cipher suites are REQUIRED to be
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 and
TLS_RSA_WITH_AES_128_CBC_SHA.
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Implementations of [RFC6012] SHOULD offer
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 but MAY offer
TLS_RSA_WITH_AES_128_CBC_SHA.
As specified in [BCP195], implementations of [RFC6012] MUST NOT use
DTLS 1.0 [RFC4347]. Implementations MUST use DTLS 1.2 [RFC6347].
DTLS 1.2 [RFC6347] implementations SHOULD support and prefer the
mandatory to implement cipher suite
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256.
As per [BCP195], implementations of [RFC6012] SHOULD support DTLS 1.3
[RFC9147] and, if implemented, MUST prefer to negotiate DTLS version
1.3 over earlier versions of DTLS.
6. Early Data
Early data (aka 0-RTT data) is a mechanism defined in TLS 1.3
[RFC8446] that allows a client to send data ("early data") as part of
the first flight of messages to a server. Early data is permitted by
TLS 1.3 when the client and server share a PSK, either obtained
externally or via a previous handshake. The client uses the PSK to
authenticate the server and to encrypt the early data.
As noted in Section 2.3 of [draft-ietf-tls-rfc8446bis-09], the
security properties for early data are weaker than those for
subsequent TLS-protected data. In particular, early data is not
forward secret, and there are no protections against the replay of
early data between connections. Appendix E.5 of
[draft-ietf-tls-rfc8446bis-09] requires applications not use early
data without a profile that defines its use. Because syslog does not
support replay protection, see Section 8.4 of [RFC5424]", and most
implementations establish a long-lived connection, this document
specifies that implementations MUST NOT use early data.
7. Authors Notes
This section will be removed prior to publication.
This is version -07 for the UTA Working Group. These edits reflect
comments from IESG review.
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8. Acknowledgments
The authors would like to thank Arijit Kumar Bose, Steffen Fries and
the members of IEC TC57 WG15 for their review, comments, and
suggestions. The authors would also like to thank Tom Petch, Juergen
Schoenwaelder, Hannes Tschofenig, Viktor Dukhovni, and the IESG
members for their comments and constructive feedback.
9. IANA Considerations
This document makes no requests to IANA.
10. Security Considerations
[BCP195] deprecates an insecure DTLS transport protocol from
[RFC6012] and deprecates insecure cipher suits from [RFC5425] and
[RFC6012]. However, the installed base of syslog implementations is
not easily updated to immediately adhere to those changes.
This document updates the mandatory to implement cipher suites to
allow for a migration from TLS_RSA_WITH_AES_128_CBC_SHA to
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 without deprecating the former.
Implementations should prefer to use
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256.
If a device currently only has TLS_RSA_WITH_AES_128_CBC_SHA, an
administrator of the network should evaluate the conditions and
determine if TLS_RSA_WITH_AES_128_CBC_SHA should be allowed so that
syslog messages may continue to be delivered until the device is
updated to have TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256.
11. References
11.1. Normative References
[BCP14] Best Current Practice 14,
<https://www.rfc-editor.org/info/bcp14>.
At the time of writing, this BCP comprises the following:
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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>.
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[BCP195] Best Current Practice 195,
<https://www.rfc-editor.org/info/bcp195>.
At the time of writing, this BCP comprises the following:
Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS
1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,
<https://www.rfc-editor.org/info/rfc8996>.
Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>.
[RFC4347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security", RFC 4347, DOI 10.17487/RFC4347, April 2006,
<https://www.rfc-editor.org/info/rfc4347>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
[RFC5424] Gerhards, R., "The Syslog Protocol", RFC 5424, March 2009,
<https://www.rfc-editor.org/rfc/rfc5424>.
[RFC5425] Miao, F., Ed., Ma, Y., Ed., and J. Salowey, Ed.,
"Transport Layer Security (TLS) Transport Mapping for
Syslog", RFC 5425, DOI 10.17487/RFC5425, March 2009,
<https://www.rfc-editor.org/info/rfc5425>.
[RFC6012] Salowey, J., Petch, T., Gerhards, R., and H. Feng,
"Datagram Transport Layer Security (DTLS) Transport
Mapping for Syslog", RFC 6012, DOI 10.17487/RFC6012,
October 2010, <https://www.rfc-editor.org/info/rfc6012>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
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[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC9147] Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
<https://www.rfc-editor.org/info/rfc9147>.
11.2. Informative References
[draft-ietf-tls-deprecate-obsolete-kex-04]
Bartle, C. and N. Aviram, "Deprecating Obsolete Key
Exchange Methods in TLS", Work in Progress, Internet-
Draft, draft-ietf-tls-deprecate-obsolete-kex-04, 11 July
2023, <https://www.ietf.org/archive/id/draft-ietf-tls-
deprecate-obsolete-kex-04.txt>.
[draft-ietf-tls-rfc8446bis-09]
Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", Work in Progress, Internet-Draft, draft-
ietf-tls-rfc8446bis-09, 7 July 2023,
<https://www.ietf.org/archive/id/draft-ietf-tls-
rfc8446bis-09.txt>.
[draft-ietf-tls-rfc8447bis-09]
Salowey, J. A. and S. Turner, "IANA Registry Updates for
TLS and DTLS", Work in Progress, Internet-Draft, draft-
ietf-tls-rfc8447bis-09, 28 March 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-tls-
rfc8447bis-09>.
Authors' Addresses
Chris Lonvick
Email: lonvick.ietf@gmail.com
Sean Turner
sn3rd
Email: sean@sn3rd.com
Joe Salowey
Venafi
Email: joe@salowey.net
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