Authentication bypass via A256GCM header confusion
Published Apr 24, 2024 · Updated Aug 2, 2024
Authentication bypass in cdbattags lua-resty-jwt 0.2.3 allows attackers to pass unsigned JWTs as verified tokens. verify_jwt_obj treats any parsed JWT carrying enc=A256GCM as a JWE, while verify_jwe_obj assumes that A256GCM authentication already occurred during JWE parsing and skips its signature check. An application must authorize requests from attacker-controlled JWTs; forged claims then receive whatever access the application assigns to those claims.
Summary
What happened
Authentication bypass in cdbattags lua-resty-jwt 0.2.3 allows attackers to pass unsigned JWTs as verified tokens. verify_jwt_obj treats any parsed JWT carrying enc=A256GCM as a JWE, while verify_jwe_obj assumes that A256GCM authentication already occurred during JWE parsing and skips its signature check. An application must authorize requests from attacker-controlled JWTs; forged claims then receive whatever access the application assigns to those claims.
The record
- CVE
- CVE-2024-33531
- Published
- Apr 24, 2024
- Updated
- Aug 2, 2024
- Vendor
- cdbattags
- Product
- lua-resty-jwt
- Classifications
- CWE-290, T1606
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 24, 2024CVE publishedPublication date reported by the CVE source.
- Aug 2, 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?
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- Affected versionversion=0.2.3
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.
Public exploit references
- A256GCM JWT authentication-bypass demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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