JWT signature, issuer, audience, or token-purpose validation failure
A service accepts token claims without the required signature or trusted issuer/key validation.
Candidate CWE: CWE-347 · CWE-287
Test hypothesis#
Compare the normal controlled token with one invalid signature. Separately use validly signed lab fixtures for a wrong issuer, audience, expiry or token purpose. Change one condition at a time; read the same harmless protected resource. Trace configured algorithm/key trust and purpose-specific validation when source is available.
Evidence required#
Show which invalid condition was accepted and the resulting synthetic identity/capability. Use CWE-347 for signature verification failures; select the actual authentication/trust weakness for semantic validation errors instead of labelling every JWT bug broken cryptography. Redact live credentials.
Rule out false positives#
Base64-decoding claims, accepting a valid token for its intended audience, or displaying untrusted claims without granting access is insufficient.
Playbook and command references#
- Authentication, recovery, federation, and session lifecycle — Test registration, recovery, identity changes, invitations, SSO enforcement, and deprovisioning as one account state machine.
- OAuth, OIDC, and SAML: transaction binding and token trust — Separate browser transaction binding, issuer trust, token purpose, and identity linking using controlled federation fixtures.
Find the associated command snippets
Referenced by these target playbooks#
Report checklist#
- Capture the affected version, configuration, identities, and object ownership.
- Preserve a valid baseline and a negative control.
- Reproduce the forbidden data access, action, or state change on controlled fixtures.
- Explain the intended security rule and why the observed behavior violates it.
- State prerequisites, uncertainty, cleanup, and the smallest demonstrated impact.
Conditional ATT&CK mapping#
No direct ATT&CK mapping selected. Record the weakness and demonstrated impact without forcing an adversary-behavior classification. See the mapping guide.