| Internet-Draft | JOSE: Deprecate 'none' and 'RSA1_5' | November 2024 |
| Madden | Expires 7 May 2025 | [Page] |
This draft updates [RFC7518] to deprecate the JWS algorithm "none" and the JWE algorithm "RSA1_5". These algorithms have known security weaknesses.¶
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.¶
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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This Internet-Draft will expire on 7 May 2025.¶
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 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.¶
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 draft deprecates two such algorithms:¶
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.¶
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-2018-1000531 - CVSS: 7.5 (High)¶
CVE-2017-10862 - CVSS: 5.3 (Medium)¶
CVE-2022-23540 - CVSS: 7.6 (High)¶
CVE-2020-15957 - CVSS: 7.5 (High)¶
CVE-2021-29500 - CVSS: 7.5 (High)¶
CVE-2021-29451 - CVSS: 9.1 (Critical)¶
CVE-2021-29455 - CVSS: 7.5 (High)¶
CVE-2021-22160 - CVSS: 9.8 (Critical)¶
CVE-2021-32631 - CVSS: 6.5 (Medium)¶
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 legitimate use-cases for Unsecured JWS, these are relatively few in number and can easily be satisfied by alternative means. 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.¶
The "RSA1_5" algorithm implements RSA encryption using PKCS#1 version 1.5 padding [RFC8017]. 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.¶
Both of the algorithms listed above are deprecated for use in JWS and JWE. JOSE library developers SHOULD deprecate support for these algorithms and commit to a timeline for removal. Application developers SHOULD 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.¶
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.¶
No security issues are introduced by this specification.¶
The following changes are to be made to the IANA JOSE Web Signature and Encryption Algorithms registry:¶
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 reasonably conjectured to meet the standard security goal of existential unforgeability under a chosen message attack (EUF-CMA) should be considered for approval.¶
For JWE key management algorithms (specified with the "alg" header), only algorithms that are reasonably conjectured to meet the standard security goal of indistinguishability under an adaptive chosen ciphertext attack (IND-CCA2) should be considered for approval.¶
For JWE content encryption methods (specified with the "enc" header), only algorithms that are reasonably conjectured to meet the standard security goal of authenticated encryption with associated data (AEAD) should be considered for approval.¶