Abstract
A Cross-Site Scripting vulnerability was found in the Top 10 - Popular posts 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-20160712-0017
Tested versions
This issue was successfully tested on Top 10 - Popular posts plugin for WordPress WordPress Plugin version 2.3.0.
Fix
This issue is resolved in Top 10 version 2.3.1.
Introduction
The Top 10 - Popular posts plugin for WordPress WordPress Plugin tracks daily and total visits on blog posts. Display the count as well as popular and trending posts. A Cross-Site Scripting vulnerability was found in the Top 10 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.
Details
The issue exists in the file class-stats.php and is caused by the lack of output encoding on the page request parameter. The vulnerable code is listed below.
<form method="get">
<input type="hidden" name="page" value="<?php **echo $_REQUEST['page']** ?>" />
<?php
// If this is a search?
if ( isset( $_REQUEST['s'] ) ) {
$args['search'] = esc_sql( $_REQUEST['s'] );
}
[...]
</form>
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=tptn_popular_posts" method="POST">
<input type="hidden" name="page" value=""<script>alert(document.cookie);</script>" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>