auth-jwt

To test JWT authentication bypass vulnerabilities, you must analyze algorithm enforcement, claim validation, and key management practices. This approach identifies flaws like algorithm confusion or weak token lifecycle management without attacking production signing keys directly.

JWT algorithm confusion occurs when an application accepts asymmetric algorithms like RS256 as symmetric HS256 tokens, allowing attackers to sign forged tokens with the public key. Evaluating algorithm enforcement detects this flaw to prevent full authentication bypass.

Validating JWT claims like exp, iat, aud, and iss requires assessing token lifecycle management and strict claim enforcement. This prevents replay attacks and privilege escalation by ensuring tokens expire correctly and match expected issuers and audiences.

You can assess JWT security posture without attacking production signing keys by analyzing test-issued tokens and the JWKS endpoint. This non-destructive security testing verifies that applications reject forged tokens and enforce strict key management practices.

JWT security testing requires structured token metadata and target-specific scope definitions to perform non-destructive security testing. These inputs authorize the assessment and define boundaries for evaluating identity providers and web applications.

Applications accept forged JWT tokens using the none algorithm due to inadequate algorithm enforcement. Reviewing token validation logic identifies this authentication bypass vulnerability by ensuring the application strictly rejects unsigned tokens.