JSON Web Tokens (JWT) are widely used for authentication and authorization in modern web applications, but they come with inherent security risks if not implemented correctly. Common vulnerabilities include algorithm confusion, where attackers can switch the signing algorithm to 'none' or use a public key as an HMAC secret. Other risks involve token expiration mishandling, weak secrets, and improper validation of claims. To defend against these attacks, developers should enforce strict algorithm whitelisting, use strong secrets, and validate all claims thoroughly. Additionally, implementing short token lifetimes and refresh token rotation can mitigate the impact of token theft. This guide provides a practical overview of JWT security, helping teams build more robust authentication systems. By understanding the attack surface, developers can proactively address vulnerabilities and protect user data from unauthorized access.
Learn about common JWT vulnerabilities, attack techniques, and best practices to secure your authentication systems.