help hacking the login form....hacker challenge

[k_tech]

ok, I came across this hacker challenge, and it seems to work like this:.... anyone can register, once you register you can login, but you get a message saying that "you are a regular user, and you need administrator rights"....all the authentication is done against a mysql backend database, which contains the usernames and passwords, with that the first thing I tried was sql injection to see if the app would spit out all the content of the table... so I tried something simple like ' or 'x'='x which in sql evaluates to true, that didn't work so I use webscarab to kind of launch a dictionary attack against the login page using sql injection, but I think the application is doing input validation or stripping the input from any tags or slashes.... the other vector attack could be either a weakness in the cookie or sessionid but I haven't got there yet.

here's the link http://www.pctechtips.org/pwn3d_login.php

any help appreciated

thanks