JWT Algorithm Confusion Vulnerability Identified in C Library
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🛠️ Critical JWT Algorithm Confusion Vulnerability Discovered in C Library. During a recent talk in Brisbane, security expert Louis Nyffenegger identified a significant algorithm confusion vulnerability in the xmidt-org/cjwt library while reviewing code. This vulnerability arises when systems fail to properly verify the signature type in JSON Web Tokens (JWTs), allowing attackers to exploit the system by using an HMAC signature where an asymmetric algorithm is expected. Nyffenegger demonstrated the issue with a proof of concept, successfully generating a malicious token that bypassed security checks. He emphasizes the importance of questioning assumptions in code reviews to uncover such vulnerabilities, urging developers to adopt a critical mindset. The vulnerability has been documented in a report, highlighting the need for improved security measures in JWT libraries.
