JOSE: Deprecate 'none' and 'RSA1_5'
draft-ietf-jose-deprecate-none-rsa15-04

Javascript Object Signing and Encryption                       N. Madden
Internet-Draft                                                 Hazelcast
Updates: 7518 (if approved)                                 2 March 2026
Intended status: Standards Track                                        
Expires: 3 September 2026

                  JOSE: Deprecate 'none' and 'RSA1_5'
                draft-ietf-jose-deprecate-none-rsa15-04

Abstract

   This document updates [RFC7518] to deprecate the JWS algorithm "none"
   and the JWE algorithm "RSA1_5".  These algorithms have known security
   weaknesses.  It also updates the Review Instructions for Designated
   Experts to establish baseline security requirements that future
   algorithm registrations should meet.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at
   https://NeilMadden.github.io/jose-deprecate-none-rsa1_5/draft-ietf-
   jose-deprecate-none-rsa15.html.  Status information for this document
   may be found at https://datatracker.ietf.org/doc/draft-ietf-jose-
   deprecate-none-rsa15/.

   Discussion of this document takes place on the Javascript Object
   Signing and Encryption Working Group mailing list
   (mailto:jose@ietf.org), which is archived at
   https://mailarchive.ietf.org/arch/browse/jose/.  Subscribe at
   https://www.ietf.org/mailman/listinfo/jose/.

   Source for this draft and an issue tracker can be found at
   https://github.com/NeilMadden/jose-deprecate-none-rsa1_5.

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/.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  The 'none' algorithm  . . . . . . . . . . . . . . . . . .   3
     1.2.  The 'RSA1_5' algorithm  . . . . . . . . . . . . . . . . .   4
     1.3.  Guidance on deprecation . . . . . . . . . . . . . . . . .   5
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   5
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  JOSE Algorithm Deprecations . . . . . . . . . . . . . . .   5
     4.2.  Updated Review Instructions for Designated Experts  . . .   6
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   JSON Web Algorithms (JWA, [RFC7518]) introduced several standard
   algorithms for both JSON Web Signature (JWS) and JSON Web Encryption
   (JWE).  Many of these algorithms have stood the test of time and are
   still in widespread use.  However, some algorithms have proved to be
   difficult to implement correctly leading to exploitable
   vulnerabilities.  This document deprecates two such algorithms:

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   *  The JWS "none" algorithm, which indicates that no security is
      applied to the message at all.

   *  The JWE "RSA1_5" algorithm, which indicates RSA encryption with
      PKCS#1 version 1.5 padding.

   Note that RSA signatures using PKCS#1 version 1.5 padding (RS256,
   RS384, and RS512) are unchanged by this specification and can still
   be used.

   Additionally, this document also updates the Review Instructions for
   the JOSE Designated Experts, to establish baseline security
   requirements for future JOSE algorithm registrations.  Only
   algorithms that are reasonably believed to satisfy these requirements
   should be registered in future.

1.1.  The 'none' algorithm

   The "none" algorithm creates an Unsecured JWS, whose contents are
   completely unsecured as the name implies.  Despite strong guidance in
   the original RFC around not accepting Unsecured JWS by default, many
   implementations have had serious bugs due to accepting this
   algorithm.  In some cases, this has led to a complete loss of
   security as authenticity and integrity checking can be disabled by an
   adversary simply by changing the algorithm ("alg") header in the JWS.
   The website [howmanydays] tracks public vulnerabilities due to
   implementations mistakenly accepting the "none" algorithm.  It
   currently lists 12 reports, many of which have high impact ratings.
   The following is a partial list of issues known to have been caused
   by misuse of the "none" algorithm, with a Common Vulnerability
   Enumeration [CVE] identifier, and a Common Vulnerability Scoring
   System [CVSS] score indicating the severity of the impact:

   *  CVE-2017-10862 (https://nvd.nist.gov/vuln/detail/CVE-2017-10862) -
      CVSS: 5.3 (Medium)

   *  CVE-2018-1000531 (https://nvd.nist.gov/vuln/detail/CVE-
      2018-1000531) - CVSS: 7.5 (High)

   *  CVE-2020-15957 (https://nvd.nist.gov/vuln/detail/CVE-2020-15957) -
      CVSS: 7.5 (High)

   *  CVE-2021-22160 (https://nvd.nist.gov/vuln/detail/CVE-2021-22160) -
      CVSS: 9.8 (Critical)

   *  CVE-2021-29500 (https://nvd.nist.gov/vuln/detail/CVE-2021-29500) -
      CVSS: 7.5 (High)

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   *  CVE-2021-29451 (https://nvd.nist.gov/vuln/detail/CVE-2021-29451) -
      CVSS: 9.1 (Critical)

   *  CVE-2021-29455 (https://nvd.nist.gov/vuln/detail/CVE-2021-29455) -
      CVSS: 7.5 (High)

   *  CVE-2021-32631 (https://nvd.nist.gov/vuln/detail/CVE-2021-32631) -
      CVSS: 6.5 (Medium)

   *  CVE-2022-23540 (https://nvd.nist.gov/vuln/detail/CVE-2022-23540) -
      CVSS: 7.6 (High)

   *  CVE-2023-29357 (https://nvd.nist.gov/vuln/detail/CVE-2023-29357) -
      CVSS: 9.8 (Critical)

   Many other vulnerabilities have been reported without an accompanying
   CVE, which we do not list here.

   Although there are some historical use-cases for Unsecured JWS that
   are not security vulnerabilities, these are relatively few in number
   and can easily be satisfied by alternative means.  For example, two
   of these are in OpenID Connect [OpenID.Core]: (1) securing unsigned
   ID Tokens via transmission over TLS in Section 3.1.3.7 and (2) the
   use of unsigned request objects in Section 6.1.  The small risk of
   breaking some of these use-cases is far outweighed by the improvement
   in security for the majority of JWS users who may be impacted by
   accidental acceptance of the "none" algorithm.

1.2.  The 'RSA1_5' algorithm

   The "RSA1_5" algorithm implements RSA encryption using PKCS#1 version
   1.5 padding [RFC8017] (section 7.2).  This padding mode has long been
   known to have security issues, since at least Bleichenbacher's attack
   in 1998.  It was supported in JWE due to the wide deployment of this
   algorithm, especially in legacy hardware.  However, more secure
   replacements such as OAEP [RFC8017] or elliptic curve encryption
   algorithms are now widely available.  NIST has disallowed the use of
   this encryption mode for federal use since the end of 2023
   [NIST.SP800-131Ar2] and a CFRG draft [I-D.irtf-cfrg-rsa-guidance]
   also deprecates this encryption mode for IETF protocols.  This
   document therefore also deprecates this algorithm for JWE.

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1.3.  Guidance on deprecation

   Both of the algorithms listed above are deprecated for use in
   JOSE—the none algorithm for JWS, and RSA1_5 for JWE.  JOSE library
   developers should deprecate support for these algorithms.
   Application developers MUST disable support for these algorithms by
   default.  New specifications building on top of JOSE MUST NOT allow
   the use of either algorithm.

   The IANA algorithm registry distinguishes between algorithms that are
   "Deprecated" and those that are "Prohibited".  The algorithms
   identified in this document are to be marked as Deprecated only.
   Existing specifications and applictions that make use of these
   algorithms can continue to do so, but should consider adopting
   alternatives in future updates.

2.  Conventions and Definitions

   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.  Security Considerations

   This entire document is concerned with security, since the security
   of JOSE implementations directly affects the security of systems that
   include them (see for example the long list of CVEs in Sec. 1.1).

4.  IANA Considerations

4.1.  JOSE Algorithm Deprecations

   The following changes are to be made to the IANA JOSE Web Signature
   and Encryption Algorithms registry:

   *  For the entry with Algorithm Name "none", update the JOSE
      Implementation Requirements to "Deprecated".

   *  For the entry with Algorithm Name "RSA1_5", update the JOSE
      Implementation Requirements to "Deprecated".

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4.2.  Updated Review Instructions for Designated Experts

   The review instructions for the designated experts for the IANA "JSON
   Web Signature and Encryption Algorithms" registry [IANA.jose] in
   Section 7.1 of [RFC7518] are updated to add these additional review
   criteria:

   *  For JWS signature algorithms, only algorithms that are believed to
      meet the standard security goal of existential unforgeability
      under a chosen message attack (EUF-CMA) should be considered for
      approval.  See textbooks such as [BonehShoup] (Section 13.1.1) for
      a definition of existential unforgeability.

   *  For JWE key management algorithms (specified with the "alg"
      header), only algorithms that are believed to meet the standard
      security goal of indistinguishability under an adaptive chosen
      ciphertext attack (IND-CCA2) should be considered for approval, as
      defined in textbooks such as [BonehShoup] (Section 9.2.2 and
      Chapter 12).

   *  For JWE content encryption methods (specified with the "enc"
      header), only algorithms that are believed to meet the standard
      security goal of authenticated encryption with associated data
      (AEAD) should be considered for approval.  See [RFC5116], and
      textbooks such as [BonehShoup] (Section 9.1), for the definition
      of AEAD security.

5.  References

5.1.  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/rfc/rfc2119>.

   [RFC5116]  McGrew, D., "An Interface and Algorithms for Authenticated
              Encryption", RFC 5116, DOI 10.17487/RFC5116, January 2008,
              <https://www.rfc-editor.org/rfc/rfc5116>.

   [RFC7518]  Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
              DOI 10.17487/RFC7518, May 2015,
              <https://www.rfc-editor.org/rfc/rfc7518>.

   [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>.

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5.2.  Informative References

   [BonehShoup]
              Boneh, D. and V. Shoup, "A Graduate Course in Applied
              Cryptography (v0.6)", 14 January 2023,
              <https://crypto.stanford.edu/~dabo/cryptobook/
              BonehShoup_0_6.pdf>.

   [CVE]      MITRE, "Common Vulnerability Enumeration Database", n.d.,
              <https://cve.mitre.org>.

   [CVSS]     FIRST, "Common Vulnerability Scoring System", n.d.,
              <https://www.first.org/cvss/>.

   [howmanydays]
              Sanderson, J., "How Many Days Has It Been Since a JWT
              alg:none Vulnerability?", 25 September 2023, <https://gith
              ub.com/zofrex/howmanydayssinceajwtalgnonevuln/blob/deploy/
              data/vulns.yml>.

   [I-D.irtf-cfrg-rsa-guidance]
              Kario, A., "Implementation Guidance for the PKCS #1 RSA
              Cryptography Specification", Work in Progress, Internet-
              Draft, draft-irtf-cfrg-rsa-guidance-06, 17 September 2025,
              <https://datatracker.ietf.org/doc/html/draft-irtf-cfrg-
              rsa-guidance-06>.

   [IANA.jose]
              IANA, "JSON Object Signing and Encryption (JOSE)",
              <https://www.iana.org/assignments/jose>.

   [NIST.SP800-131Ar2]
              Barker, E. and A. Roginsky, "Transitioning the use of
              cryptographic algorithms and key lengths", National
              Institute of Standards and Technology,
              DOI 10.6028/nist.sp.800-131ar2, March 2019,
              <https://doi.org/10.6028/nist.sp.800-131ar2>.

   [OpenID.Core]
              Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
              C. Mortimore, "OpenID Connect Core 1.0 incorporating
              errata set 2", December 2023,
              <https://openid.net/specs/openid-connect-core-1_0.html>.

   [RFC8017]  Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
              "PKCS #1: RSA Cryptography Specifications Version 2.2",
              RFC 8017, DOI 10.17487/RFC8017, November 2016,
              <https://www.rfc-editor.org/rfc/rfc8017>.

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Appendix A.  Acknowledgments

   The author would like to thank the following people for feedback and
   useful suggestions: Mike Ounsworth, Michael B.  Jones, Yaron Sheffer,
   Brian Campbell, Aaron Parecki, Filip Skokan, Tim Bray, and John
   Mattsson.

Author's Address

   Neil Madden
   Hazelcast
   Email: neil.e.madden@gmail.com

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