Authentication bypass via public-key HMAC confusion
Published Dec 19, 2024 · Updated Dec 20, 2024
Algorithm confusion in XMiDT cjwt before 2.3.0 allows remote attackers to forge accepted JWTs by substituting an HMAC algorithm. cjwt_decode trusted the token's alg header and could treat an asymmetric public key as an HMAC secret instead of enforcing the caller's expected key type. Exploitation requires a consuming application to expect an asymmetric JWT, pass its public key to cjwt_decode, and trust the decoded claims for authorization.
Summary
What happened
Algorithm confusion in XMiDT cjwt before 2.3.0 allows remote attackers to forge accepted JWTs by substituting an HMAC algorithm. cjwt_decode trusted the token's alg header and could treat an asymmetric public key as an HMAC secret instead of enforcing the caller's expected key type. Exploitation requires a consuming application to expect an asymmetric JWT, pass its public key to cjwt_decode, and trust the decoded claims for authorization.
The record
- CVE
- CVE-2024-54150
- Published
- Dec 19, 2024
- Updated
- Dec 20, 2024
- Vendor
- XMiDT
- Product
- cjwt
- Classifications
- CWE-347, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 19, 2024CVE publishedPublication date reported by the CVE source.
- Dec 20, 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=< 2.3.0
What conditions does exploitation require?
What is affected?
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
- GitHub advisory 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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