Closed Bug 1494738 Opened 6 years ago Closed 5 months ago

Web Authentication - Mandate minimum Challenge state space / length

Categories

(Core :: DOM: Web Authentication, enhancement, P2)

64 Branch
enhancement

Tracking

()

RESOLVED WONTFIX
Tracking Status
firefox64 --- affected

People

(Reporter: jcj, Unassigned)

References

Details

(Whiteboard: [webauthn][webauthn-interop])

The WebAuthn spec uses loose language to demand that challenges used in WebAuthn be random to protect from replay attacks [0]. Right now Firefox relies on the server to provide good randomness, but we should do some basic checks (e.g., that it's not empty or really small). There's a SHOULD sentence suggesting 16 bytes, and I think we could just check that we have at least 8 bytes and bail if not.

[0] https://w3c.github.io/webauthn/#cryptographic-challenges
Component: DOM: Device Interfaces → DOM: Web Authentication
Severity: normal → S3
Status: NEW → RESOLVED
Closed: 5 months ago
Resolution: --- → WONTFIX
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