Security Bughunt

2017 - August - Amsterdam

2017 Target - IoT



Yorick Koster, March 2017

Simple Ads Manager WordPress plugin unauthenticated PHP Object injection vulnerability

Abstract

A PHP Object injection vulnerability was found in the Simple Ads Manager WordPress plugin. The unauthenticated PHP Object injection vulnerability can be used by an unautenthicated user to instantiate arbitrary PHP Objects. This issue can potentially result in arbitrary code execution, but this has not been confirmed.

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-20160712-0041

Tested versions

This issue was succesfully tested on the Simple Ads Manager WordPress plugin version 2.9.8.125.

Fix

There is currently no fix available.

Introduction

The Simple Ads Manager WordPress Plugin is an easy to use plugin providing a flexible logic of displaying advertisements. A PHP Object injection vulnerability was found in Simple Ads Manager WordPress plugin. The unauthenticated PHP Object injection vulnerability can be used by an unautenthicated user to instantiate arbitrary PHP Objects.

Details

This issue is possible due to two unsafe calls to unserialize() in the sam-ajax-loader.php file. The input is taken directly from the POST request as can be seen in the following code fragment:

sam-ajax-loader.php:

if ( in_array( $action, $allowed_actions ) ) {
   switch ( $action ) {
      case 'sam_ajax_load_place':
         echo json_encode( array( 'success' => false, 'error' => 'Deprecated...' ) );
         break;
   
      case 'sam_ajax_load_ads':
         if ( ( isset( $_POST['ads'] ) && is_array( $_POST['ads'] ) ) && isset( $_POST['wc'] ) ) {
            $clauses = unserialize( base64_decode( $_POST['wc'] ) );

This issue can potentially result in arbitrary code execution, but this has not been confirmed.