Remove SHA-1 from active use within DNSSEC
draft-ietf-dnsop-must-not-sha1-00

Network Working Group                                        W. Hardaker
Internet-Draft                                                   USC/ISI
Intended status: Standards Track                               W. Kumari
Expires: 9 January 2025                                           Google
                                                             8 July 2024

               Remove SHA-1 from active use within DNSSEC
                   draft-ietf-dnsop-must-not-sha1-00

Abstract

   This document retires the use of SHA-1 within DNSSEC.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on 9 January 2025.

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   2
   2.  Deprecating SHA-1 algorithms in DNSSEC  . . . . . . . . . . .   3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   3
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .   5
   Appendix B.  Current algorithm usage levels . . . . . . . . . . .   5
   Appendix C.  Github Version of this document  . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The security of the SHA-1 algorithm [RFC3174] has been slowly
   diminishing over time as various forms of attacks have weakened its
   cryptographic underpinning.  DNSSEC [RFC4033] [RFC4034] [RFC4035]
   originally made extensive use of SHA-1 as a cryptographic
   verification algorithm in RRSIG and Delegation Signer (DS) records,
   for example.  Since then, multiple other signing algorithms with
   stronger cryptographic strength are now widely available for DS
   records (such as SHA-256 [RFC4509], SHA-384 ([RFC6605])) and for
   DNSKEY and RRSIG records (such as RSASHA256 ([RFC5702]), RSASHA512
   ([RFC5702]), ECDSAP256SHA256 [RFC6605], ECDSAP384SHA384 [RFC6605],
   ED25519 [RFC8080], and ED448 [RFC8080]).  Further, support for
   validating SHA-1 based signatures has been removed from some systems.
   As a result, SHA-1 is no longer fully interoperable in the context of
   DNSSEC.  As adequate alternatives exist, the use of SHA-1 is no
   longer advisable.

   This document thus further deprecates the use of RSASHA1 and
   RSASHA1-NSEC3-SHA1 for DNS Security Algorithms.

1.1.  Requirements notation

   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.

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2.  Deprecating SHA-1 algorithms in DNSSEC

   The RSASHA1 [RFC4034] and RSASHA1-NSEC3-SHA1 [RFC5155] algorithms
   MUST NOT be used when creating DNSKEY and RRSIG records.

   Validating resolvers MUST continue to support validation using these
   algorithms as they are diminishing in use but still actively in use
   for some domains as of this publication.  Validating resolvers MAY
   treat RRSIG records created from DNSKEY records using these
   algorithms as an unsupported algorithm.

3.  Security Considerations

   This document reduces the risk that a zone cannot be validated due to
   lack of SHA-1 support in a validator, by guiding signers to choose a
   more interoperable signing algorithm.

4.  Operational Considerations

   Zone owners currently making use of SHA-1 based algorithms should
   immediately switch to algorithms with stronger cryptographic
   strengths, such as those listed in the introduction.

5.  IANA Considerations

   IANA is requested to set the "Use for DNSSEC Delegation" field of the
   "Digest Algorithms" registry [DS-IANA] for SHA-1 (1) to MUST NOT.

   IANA is requested to set the "Use for DNSSEC Signing" column of the
   DNS Security Algorithm Numbers registry [DNSKEY-IANA] to MUST NOT for
   the RSASHA1 (5) and RSASHA1-NSEC3-SHA1 (7) algorithms.

   All other columns should remain as currently specified.

6.  References

6.1.  Normative References

   [DNSKEY-IANA]
              IANA, "Domain Name System Security (DNSSEC) Algorithm
              Numbers", n.d., <https://www.iana.org/assignments/dns-sec-
              alg-numbers/dns-sec-alg-numbers.xhtml>.

   [DS-IANA]  IANA, "Delegation Signer (DS) Resource Record (RR) Type
              Digest Algorithms", n.d.,
              <http://www.iana.org/assignments/ds-rr-types>.

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   [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/rfc/rfc2119>.

   [RFC3174]  Eastlake 3rd, D. and P. Jones, "US Secure Hash Algorithm 1
              (SHA1)", RFC 3174, DOI 10.17487/RFC3174, September 2001,
              <https://www.rfc-editor.org/rfc/rfc3174>.

   [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "DNS Security Introduction and Requirements",
              RFC 4033, DOI 10.17487/RFC4033, March 2005,
              <https://www.rfc-editor.org/rfc/rfc4033>.

   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              RFC 4034, DOI 10.17487/RFC4034, March 2005,
              <https://www.rfc-editor.org/rfc/rfc4034>.

   [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Protocol Modifications for the DNS Security
              Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
              <https://www.rfc-editor.org/rfc/rfc4035>.

   [RFC4509]  Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer
              (DS) Resource Records (RRs)", RFC 4509,
              DOI 10.17487/RFC4509, May 2006,
              <https://www.rfc-editor.org/rfc/rfc4509>.

   [RFC5155]  Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
              Security (DNSSEC) Hashed Authenticated Denial of
              Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008,
              <https://www.rfc-editor.org/rfc/rfc5155>.

   [RFC5702]  Jansen, J., "Use of SHA-2 Algorithms with RSA in DNSKEY
              and RRSIG Resource Records for DNSSEC", RFC 5702,
              DOI 10.17487/RFC5702, October 2009,
              <https://www.rfc-editor.org/rfc/rfc5702>.

   [RFC6605]  Hoffman, P. and W.C.A. Wijngaards, "Elliptic Curve Digital
              Signature Algorithm (DSA) for DNSSEC", RFC 6605,
              DOI 10.17487/RFC6605, April 2012,
              <https://www.rfc-editor.org/rfc/rfc6605>.

   [RFC8080]  Sury, O. and R. Edmonds, "Edwards-Curve Digital Security
              Algorithm (EdDSA) for DNSSEC", RFC 8080,
              DOI 10.17487/RFC8080, February 2017,
              <https://www.rfc-editor.org/rfc/rfc8080>.

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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/rfc/rfc8174>.

Appendix A.  Acknowledgments

   TBD

Appendix B.  Current algorithm usage levels

   The DNSSEC scanning project by Viktor Dukhovni and Wes Hardaker
   highlights the current deployment of various algorithms on the
   https://stats.dnssec-tools.org/ website.

   <RFC Editor: please delete this section upon publication>

Appendix C.  Github Version of this document

   While this document is under development, it can be viewed, tracked,
   fill here:

   https://github.com/hardaker/draft-hardaker-dnsop-must-not-sha1

Authors' Addresses

   Wes Hardaker
   USC/ISI
   Email: ietf@hardakers.net

   Warren Kumari
   Google
   Email: warren@kumari.net

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