GHSA-gwjm-x277-ww8p: 
JavaScript vulnerability analysis and mitigation

Impact

signHttpRequest / sign_http_request build the HTTP signature base from @request-target, host, date, content-digest and x-request-nonce, but do not include the "@signature-params" line required by RFC 9421 section 2.5. The created, expires, keyid and alg parameters in Signature-Input are therefore not signed. An attacker who captures a signed request can rewrite created and expires to current values and the signature still verifies. The project's anti-replay guidance tells verifiers to purge cached nonces once expires has passed, so after that point the captured request can be replayed indefinitely. The covered Date header does not prevent this because the verifier does not check its freshness. Exploitation requires access to a previously signed request (for example through logs, a compromised intermediary, or TLS termination).

Patches

The signature base now ends with an "@signature-params" line carrying the exact Signature-Input value, and verifiers rebuild it from the received header. Fixed in @agentdid/sdk 1.0.0-rc.1 and agent-did-sdk 1.0.0rc1. This is a breaking wire change: signatures from affected versions do not verify with patched versions.

Workarounds

On affected versions, verifiers should reject any request whose Date header is outside a short accepted skew window. Date is covered by the signature, so it cannot be rewritten. They should also keep each nonce in the replay cache for at least that window, measured from Date rather than from the unsigned expires value.

References

• RFC 9421 section 2.5 (Creating the Signature Base)