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Username Enumeration with ffuf

enumerationtool

Summary

Enumerates valid usernames through a signup form by matching the "username already exists" response with ffuf.

Walkthrough

Use ffuf to find valid usernames by abusing a signup/registration form that reveals when a name is already taken.

Steps

  • Send a POST request with FUZZ in the username field and dummy values for the others.
  • Set the form content type with -H.
  • Use -mr "username already exists" to match the response that signals a valid existing username.

Commands

bash

ffuf -w /usr/share/wordlists/SecLists/Usernames/Names/names.txt -X POST -d "username=FUZZ&email=x&password=x&cpassword=x" -H "Content-Type: application/x-www-form-urlencoded" -u http://<TARGET>/customers/signup -mr "username already exists"