Hunt Agent Brute-Force & Rate Limiting

Tools that accept guesses (PINs, tokens, passwords) without rate limiting or lockout are brute-forceable, and any feedback ("digit correct," "too high") is an oracle that collapses the search space. In enterprises this is agent-fronted MFA/OTP/PIN checks, coupon/voucher validation, and token verification exposed as a tool.

Where This Lives / Attack Surface Signals

• Tools that accept guesses: check_pin, verify_token, guess, validate, unlock.
• Feedback returned: "X digits correct," "Y in position," "too high/low."
• Known-format secret (4 digits, 6 hex, etc.); no mention of rate limit/lockout/max attempts.
• Agent encourages retries ("try again!").

Crown Jewel Targets

Agent-fronted authentication (OTP/PIN/API-token verification), voucher/coupon systems, "unlock" gates — recovery = account/resource access.

Characterize First

1. Search space — 4 digits (10k), 6 hex (16M), alphanumeric (larger)?
2. Rate limiting — send 5 rapid guesses; all answered = none.
3. Lockout — send 10 wrong; if the 11th still works = none.
4. Feedback — what does each guess reveal? More feedback = faster elimination.