1. We send a POST request to `/api/login` using the username admin and a regex match query for the password with a random (printable) character.
2. If the login is successful, we assume that this character is indeed part of the password, so we add it to our flag, and try again with the next position in the password
3. Simple as that, let's script it

Original writeup (https://kblagoev.com/blog/wild-goose-hunt-cyberapocalypse-2021-ctf/).