Token forgery via asymmetric-key HMAC confusion
Published Apr 25, 2024 · Updated Sep 3, 2024
Algorithm confusion in python-jose 3.3.0 and earlier allows remote attackers to forge JWTs with an OpenSSH ECDSA public key. When jwt.decode omits an algorithms allowlist, the cryptography backend's prefix blacklist accepts that public key as an HMAC secret. A target application must verify attacker-supplied HS256 tokens with an asymmetric public key; successful forgery bypasses token authentication and grants the impersonated identity's access.
Summary
What happened
Algorithm confusion in python-jose 3.3.0 and earlier allows remote attackers to forge JWTs with an OpenSSH ECDSA public key. When jwt.decode omits an algorithms allowlist, the cryptography backend's prefix blacklist accepts that public key as an HMAC secret. A target application must verify attacker-supplied HS256 tokens with an asymmetric public key; successful forgery bypasses token authentication and grants the impersonated identity's access.
The record
- CVE
- CVE-2024-33663
- Published
- Apr 25, 2024
- Updated
- Sep 3, 2024
- Vendor
- python-jose project
- Product
- python-jose
- Classifications
- CWE-327, T1550.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 25, 2024CVE publishedPublication date reported by the CVE source.
- Sep 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=3.3.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- OpenSSH ECDSA key algorithm-confusion proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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