webeasy

Flag checker

hackerlab

Task: a Flask/Werkzeug web service lets users verify a flag through a separate `/check` endpoint. Solution: inspect the frontend JavaScript, detect that the API leaks whether the submitted value is a correct prefix, and brute-force the flag one character at a time until the endpoint returns full success.

$ ls tags/ techniques/
brute_forceflaskwerkzeugprefix_oracleflag_validationapplication_logic_flaw
prefix_oracle_bruteforceresponse_based_enumeration
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