Individual skill

hunt-mfa-bypass

Hunt MFA / 2FA bypass — 7 distinct patterns. (1) MFA not enforced on sensitive endpoints (password change, email change accept without MFA challenge), (2) MFA-step skip via direct navigation to post-login URL, (3) MFA-token replay (same code accepted twice), (4) brute-force the 6-digit OTP without rate limit (10^6 attempts at server speed), (5) race condition on OTP validation, (6) recovery-code dump via /api/me, (7) backup factor downgrade (SMS factor with no rate limit). Plus the chain: cookie theft + password oracle + no step-up = ATO without MFA challenge. Detection: trace auth flow in Burp, find every state transition, check if MFA is middleware-gated vs per-endpoint, check OTP entropy and rate limit on OTP-validate. Validate: attacker session reaching post-MFA state. Use when hunting auth bypass, MFA flows, chaining primitives toward ATO.

knowledge/Claude-BugHunter/skills/hunt-mfa-bypass/SKILL.md

Source commit 961a0dd3d2d2f66a07a416ade3b1d4473b64802e

What was checked

Matches the observed repository HEAD

Yes

Scanner rules are current

No

Repository scan complete

No

Skill scan complete

No

Observed behavior

Not checked yet

Last checked

Nov 4, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

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