WordPress CMS Commander Client Plugin unauthenticated PHP Object injection vulnerability

Abstract
A PHP Object injection vulnerability was found in the CMS Commander Client WordPress Plugin, which can be used by an unauthenticated user to instantiate arbitrary PHP Objects. Using this vulnerability it is possible to execute arbitrary PHP code.

Contact
For feedback or questions about this advisory mail us at sumofpwn at securify.nl

The Summer of Pwnage
This issue has been found during the Summer of Pwnage hacker event, running from July 1-29. A community summer event in which a large group of security bughunters (worldwide) collaborate in a month of security research on Open Source Software (WordPress this time). For fun. The event is hosted by Securify in Amsterdam.

OVE ID
OVE-20160803-0003

Tested versions
This issue was successfully tested on the CMS Commander Client WordPress Plugin version 2.21.

Fix
Input validation was added to version 2.22 of CMS Commander Client to mitigate this issue.

Introduction
The CMS Commander Client WordPress Plugin can manage multiple WordPress sites from a single dashboard. A PHP Object injection vulnerability was found in the CMS Commander Client WordPress Plugin, which can be used by an unauthenticated user to instantiate arbitrary PHP Objects.

Details
This issue is possible due to an unsafe call to unserialize() in the cmsc_authenticate() method. The input is taken directly from the POST body as can be seen in the following code fragment:

functions.php:
if( !function_exists('cmsc_authenticate')) {
function cmsc_authenticate() {

global $_cmsc_data, $_cmsc_auth, $cmsc_core;

if (!isset($HTTP_RAW_POST_DATA)) {
$HTTP_RAW_POST_DATA = file_get_contents('php://input');
}
/*if(substr($HTTP_RAW_POST_DATA, 0, 7) == "action="){
$HTTP_RAW_POST_DATA = str_replace("action=", "", $HTTP_RAW_POST_DATA);
}*/

$_cmsc_data = base64_decode($HTTP_RAW_POST_DATA);
if (!$_cmsc_data){
return;
}
$_cmsc_data = cmsc_parse_data( @unserialize($_cmsc_data) );

It has been confirmed that this issues can be used to execute arbitrary PHP code.

#  0day.today [2018-03-31]  #