



Network                                                  P. Wouters, Ed.
Internet-Draft                                                     Aiven
Updates: 8221, 8247 (if approved)                       19 December 2022
Intended status: Standards Track                                        
Expires: 22 June 2023


             Deprecation of IKEv1 and obsoleted algorithms
              draft-ietf-ipsecme-ikev1-algo-to-historic-09

Abstract

   Internet Key Exchange version 1 (IKEv1) has been deprecated and its
   specification in RFC2407, RFC2408 and RFC2409 have been moved to
   Historic status.  This document updates RFC 8221 and RFC 8247 to
   reflect the usage guidelines of old algorithms that are associated
   with IKEv1, and are not specified or commonly implemented for IKEv2.
   This document further updates the IANA IKEv2 Transform Type
   registries to add a Status column where deprecation status can be
   listed.

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 22 June 2023.

Copyright Notice

   Copyright (c) 2022 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
   and restrictions with respect to this document.  Code Components



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   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.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  RFC2407, RFC2408 and RFC2409 are Historic . . . . . . . . . .   3
   4.  IKEv1 feature equivalents for IKEv2 . . . . . . . . . . . . .   4
     4.1.  IKEv2 postquantum support . . . . . . . . . . . . . . . .   4
     4.2.  IKEv2 Labeled IPsec support . . . . . . . . . . . . . . .   4
     4.3.  IKEv2 Group SA / Multicast support  . . . . . . . . . . .   4
   5.  Deprecating obsolete algorithms . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   IKEv1 has been moved to Historic status.  IKEv1 [RFC2409] and its
   related documents for ISAKMP [RFC2408] and IPsec DOI [RFC2407] were
   obsoleted by IKEv2 [RFC4306] in December 2005.  The latest version of
   IKEv2 at the time of writing was published in 2014 in [RFC7296].  The
   Internet Key Exchange (IKE) version 2 has replaced version 1 over 15
   years ago.  IKEv2 has now seen wide deployment and provides a full
   replacement for all IKEv1 functionality.  No new modifications or new
   algorithms have been accepted for IKEv1 for at least a decade.  IKEv2
   addresses various issues present in IKEv1, such as IKEv1 being
   vulnerable to amplification attacks.

   Algorithm implementation requirements and usage guidelines for IKEv2
   [RFC8247] and ESP/AH [RFC8221] gives guidance to implementors but
   limits that guidance to avoid broken or weak algorithms.  These two
   RFCs do not deprecate algorithms that have aged and are not in use,
   but leave these algorithms in a state of "MAY be used" by not
   mentioning them.  This document deprecates those unmentioned
   algorithms that are no longer advised but for which there are no
   known attacks resulting in their earlier deprecation.









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2.  Requirements Language

   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.  RFC2407, RFC2408 and RFC2409 are Historic

   IKEv1 is deprecated.  Systems running IKEv1 should be upgraded and
   reconfigured to run IKEv2.  Systems that support IKEv1 but not IKEv2
   are most likely also unsuitable candidates for continued operation:

   *  IKEv1 development ceased over a decade ago and no new work will
      happen.  This poses the risk of unmaintained code in an otherwise
      supported product which can result in security vulnerabilities.

   *  A number of IKEv1 systems have reached their End of Life and
      therefor will never be patched by the vendor if a vulnerability is
      found.

   *  There are vendors that still provide updates for their equipment
      that supports IKEv1 and IKEv2, but have "frozen" their IKEv1
      implementation.  Such users might not be aware that they are
      running unmaintained code with its associated security risks.

   *  IKEv1 systems can be abused for packet amplification attacks, as
      documented in the Security Bulletin [CVE-2016-5361].

   *  Great strides have been made in cryptography since IKEv1
      development ceased.  While some modern cryptographic algorithms
      were added to IKEv1, interoperability concerns mean that the
      defacto algorithms negotiated by IKEv1 will consist of dated or
      deprecated algorithms like AES-CBC, SHA1, and Diffie-Hellman
      groups 1 or 2.  IKEv2 provides state-of-the-art suite of
      cryptographic algorithms that IKEv1 lacks.

   IKEv2 is a more secure protocol than IKEv1.  For example, IKEv2
   offers more modern cryptographic primitives, proper defense against
   denial of service attacks, improved authentication via EAP methods,
   PAKE support and is actively worked on with respect to defending
   against quantum computer attacks.

   IKEv1-only systems should be upgraded or replaced by systems
   supporting IKEv2.  IKEv2 implementations SHOULD NOT directly import
   IKEv1 configurations without updating the cryptographic algorithms
   used.



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4.  IKEv1 feature equivalents for IKEv2

   A few notable IKEv1 features are not present in the IKEv2 core
   specification [RFC7296] but are available for IKEv2 via an additional
   specification:

4.1.  IKEv2 postquantum support

   IKEv1 and its way of using Preshared Keys (PSKs) protects against
   quantum computer based attacks.  IKEv2 updated its use of PSK to
   improve the error reporting, but at the expense of post-quantum
   security.  If post-quantum security is required, these systems should
   be migrated to use IKEv2 Postquantum Preshared Keys (PPK) [RFC8784]

4.2.  IKEv2 Labeled IPsec support

   Some IKEv1 implementations support Labeled IPsec, a method to
   negotiate an additional Security Context selector to the SPD, but
   this method was never standardized in IKEv1.  Those IKEv1 systems
   that require Labeled IPsec should migrate to an IKEv2 system
   supporting Labeled IPsec as specified in
   [draft-ietf-ipsecme-labeled-ipsec].

4.3.  IKEv2 Group SA / Multicast support

   The Group Domain of Interpretation (GDOI, [RFC6407]) protocol, based
   on IKEv1 defines the support for Multicast Group SAs.  For IKEv2,
   this work is currently in progress via [draft-ietf-ipsecme-g-ikev2]

5.  Deprecating obsolete algorithms

   This document deprecates the following algorithms:

   *  Encryption Algorithms: RC5, IDEA, CAST, Blowfish, and the
      unspecified 3IDEA, ENCR_DES_IV64 and ENCR_DES_IV32

   *  PRF Algorithms: the unspecified PRF_HMAC_TIGER

   *  Integrity Algorithms: HMAC-MD5-128

   *  Diffie-Hellman groups: none

6.  Security Considerations

   There are only security benefits by deprecating IKEv1 for IKEv2.






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   The deprecated algorithms have long been in disuse and are no longer
   actively deployed or researched.  It presents an unknown security
   risk that is best avoided.  Additionally, these algorithms not being
   supported in implementations simplifies those implementations and
   reduces the accidental use of these deprecated algorithms through
   misconfiguration or downgrade attacks.

7.  IANA Considerations

   This document instructs IANA to insert the following line at the top
   of the Notes section of the 'Internet Key Exchange (IKE) Attributes'
   registry and the '"Magic Numbers" for ISAKMP Protocol' registry: All
   registries listed below have been closed, see RFCxxxx.  [Note to RFC
   Editor: change RFCxxx to this document's RFC number]

   This document further instructs IANA to add an additional Status
   column to the IKEv2 Transform Type registries and mark the following
   entries as DEPRECATED:


             Transform Type 1 - Encryption Algorithm IDs

             Number    Name                Status
             ------    ---------------     ------
             1         ENCR_DES_IV64       DEPRECATED [this document]
             2         ENCR_DES            DEPRECATED [RFC8247]
             4         ENCR_RC5            DEPRECATED [this document]
             5         ENCR_IDEA           DEPRECATED [this document]
             6         ENCR_CAST           DEPRECATED [this document]
             7         ENCR_BLOWFISH       DEPRECATED [this document]
             8         ENCR_3IDEA          DEPRECATED [this document]
             9         ENCR_DES_IV32       DEPRECATED [this document]

                                  Figure 1

             Transform Type 2 - Pseudorandom Function Transform IDs

             Number    Name                Status
             ------    ------------        ----------
             1         PRF_HMAC_MD5        DEPRECATED [RFC8247]
             3         PRF_HMAC_TIGER      DEPRECATED [this document]

                                  Figure 2








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             Transform Type 3 - Integrity Algorithm Transform IDs

             Number    Name                Status
             ------    -----------------   ----------
             1         AUTH_HMAC_MD5_96    DEPRECATED [RFC8247]
             3         AUTH_DES_MAC        DEPRECATED [RFC8247]
             4         AUTH_KPDK_MD5       DEPRECATED [RFC8247]
             6         AUTH_HMAC_MD5_128   DEPRECATED [this document]
             7         AUTH_HMAC_SHA1_160  DEPRECATED [this document]

                                  Figure 3

           Transform Type 4 - Diffie Hellman Group Transform IDs

           Number    Name                           Status
           ------    ----------------------------   ----------
           1         768-bit MODP Group             DEPRECATED [RFC8247]
           22        1024-bit MODP Group with
                     160-bit Prime Order Subgroup   DEPRECATED [RFC8247]

                                Figure 4

   All entries not mentioned here should receive no value in the new
   Status field.

8.  References

8.1.  Normative References

   [RFC2119]  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>.

   [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>.

   [RFC8247]  Nir, Y., Kivinen, T., Wouters, P., and D. Migault,
              "Algorithm Implementation Requirements and Usage Guidance
              for the Internet Key Exchange Protocol Version 2 (IKEv2)",
              RFC 8247, DOI 10.17487/RFC8247, September 2017,
              <https://www.rfc-editor.org/info/rfc8247>.

8.2.  Informative References






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   [CVE-2016-5361]
              National Institute of Science and Technology (NIST),
              "National Vulnerability Database - CVE-2016-5361", 16 June
              2016, <https://nvd.nist.gov/vuln/detail/CVE-2016-5361>.

   [draft-ietf-ipsecme-g-ikev2]
              Smyslov, V. and B. Weis, "Group Key Management using
              IKEv2", Work in Progress, Internet-Draft, draft-ietf-
              ipsecme-g-ikev2, 11 January 2021,
              <https://www.ietf.org/archive/id/draft-ietf-ipsecme-
              g-ikev2-03.txt>.

   [draft-ietf-ipsecme-labeled-ipsec]
              Wouters, P. and S. Prasad, "Labeled IPsec Traffic Selector
              support for IKEv2", Work in Progress, Internet-Draft,
              draft-ietf-ipsecme-labeled-ipsec, 25 October 2021,
              <https://tools.ietf.org/id/draft-ietf-ipsecme-labeled-
              ipsec-06.txt>.

   [RFC2407]  Piper, D., "The Internet IP Security Domain of
              Interpretation for ISAKMP", RFC 2407,
              DOI 10.17487/RFC2407, November 1998,
              <https://www.rfc-editor.org/info/rfc2407>.

   [RFC2408]  Maughan, D., Schertler, M., Schneider, M., and J. Turner,
              "Internet Security Association and Key Management Protocol
              (ISAKMP)", RFC 2408, DOI 10.17487/RFC2408, November 1998,
              <https://www.rfc-editor.org/info/rfc2408>.

   [RFC2409]  Harkins, D. and D. Carrel, "The Internet Key Exchange
              (IKE)", RFC 2409, DOI 10.17487/RFC2409, November 1998,
              <https://www.rfc-editor.org/info/rfc2409>.

   [RFC4306]  Kaufman, C., Ed., "Internet Key Exchange (IKEv2)
              Protocol", RFC 4306, DOI 10.17487/RFC4306, December 2005,
              <https://www.rfc-editor.org/info/rfc4306>.

   [RFC6407]  Weis, B., Rowles, S., and T. Hardjono, "The Group Domain
              of Interpretation", RFC 6407, DOI 10.17487/RFC6407,
              October 2011, <https://www.rfc-editor.org/info/rfc6407>.

   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.






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   [RFC8221]  Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T.
              Kivinen, "Cryptographic Algorithm Implementation
              Requirements and Usage Guidance for Encapsulating Security
              Payload (ESP) and Authentication Header (AH)", RFC 8221,
              DOI 10.17487/RFC8221, October 2017,
              <https://www.rfc-editor.org/info/rfc8221>.

   [RFC8784]  Fluhrer, S., Kampanakis, P., McGrew, D., and V. Smyslov,
              "Mixing Preshared Keys in the Internet Key Exchange
              Protocol Version 2 (IKEv2) for Post-quantum Security",
              RFC 8784, DOI 10.17487/RFC8784, June 2020,
              <https://www.rfc-editor.org/info/rfc8784>.

Author's Address

   Paul Wouters (editor)
   Aiven
   Email: paul.wouters@aiven.io

































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