Lord of SQL injection – darkknight

Level 12

Source Code

<?php 
  include "../config.php"; 
  login_chk(); 
  dbconnect(); 
  if(preg_match('/prob|_|\.|\(\)/i', $_GET[no])) exit("No Hack ~_~"); 
  if(preg_match('/\'/i', $_GET[pw])) exit("HeHe"); 
  if(preg_match('/\'|substr|ascii|=/i', $_GET[no])) exit("HeHe"); 
  $query = "select id from prob_darkknight where id='guest' and pw='{$_GET[pw]}' and no={$_GET[no]}"; 
  echo "<hr>query : <strong>{$query}</strong><hr><br>"; 
  $result = @mysql_fetch_array(mysql_query($query)); 
  if($result['id']) echo "<h2>Hello {$result[id]}</h2>"; 
   
  $_GET[pw] = addslashes($_GET[pw]); 
  $query = "select pw from prob_darkknight where id='admin' and pw='{$_GET[pw]}'"; 
  $result = @mysql_fetch_array(mysql_query($query)); 
  if(($result['pw']) && ($result['pw'] == $_GET['pw'])) solve("darkknight"); 
  highlight_file(__FILE__); 
?>

Analyse

http://los.sandbox.cash/darkknight-~~.php?pw=123&no=12 이라고 입력하게 되면
select id from prob_darkknight where id='guest' and pw='123' no=12과 같이 MySQL 쿼리문이 입력된다.
그리고 5번째 줄에서 ‘or’, ‘and’, ‘substr’, ‘=’, ‘ascii’이 필터링 되어있다.
 15번째 줄을 보면 &result['pw']에 admin의 pw가 들어가야만 darkknight문제가 풀린다.

Frist Hint is next page