http://www.hackthis.co.uk/ctf/4

gistfile1.php

<?php
    //Note: PHP < 4.2.0 only
    $user = $_POST['user'];
    $pass = $_POST['pass'];

    if ($user->login($user, $pass)) {
        $loggedIn = true;
        if ($user->isAdmin()) {
            $priv = 1;
        }
    }

    // ...

    if (!$loggedIn) {
        include("login.php");
    } else if ($priv > 0) {
        include("admin.php");
    } else {
        include("intro.php");
    }
?>