The information has been provided by Gabriel Quadros.
The original article can be found at: http://seclists.org/fulldisclosure/2011/Mar/206
* Related Posts Wordress Plugin
This advisory describes multiple Stored Cross Site Scripting (XSS) vulnerabilities and one Cross Site Request Forgery (CSRF) vulnerability on the plugin. As a result, an attacker can gain elevated access privileges to sensitive page content, session cookies, and a variety of other information maintained by the browser on behalf of the WordPress administrator user. Furthermore, the attacker can perform actions with administrative powers.
This problem was confirmed in the latest version of the plugin, other versions maybe also affected.
The plugin's configuration page is vulnerable to Stored Cross Site Scripting. The three fields wp_relatedposts_ title, wp_relatedposts_num and wp_relatedposts_type are received through POST or GET and included on the response page with little sanitization.
The vulnerable code is shown next:
158: <tr valign="top">
159: <th scope="row">Title:</th>
160: <td><input type="text" name="wp_relatedposts_title" value="<?=$options['
162: <tr valign="top">
163: <th scope="row">Number posts:</th>
164: <td><input type="text" name="wp_relatedposts_num" value="<?=$options['
166: <tr valign="top">
167: <th scope="row">Related on:</th>
169: <select name="wp_relatedposts_type">
170: <option selected
171: <option value="Tags">Tags</option>
172: <option value="Category">Category</option>
Another vulnerable piece of code is the one which prints the related posts list. The title (received through the parameter wp_relatedposts_title is included with little sanitization into suchs lists. The vulnerable code is shown next:
79: $relatedpost.= '<br><br><br><h3>' . $options['title'] . '</h3><ul>';
120: $relatedpost.= '<br><br><br><h3>' . $options['title'] . '</h3><ul>';
Since the plugin's configuration page is not protected against Cross Site Request Forgery, the exploitation permits the attacker to inject configuration values.
Proof of concept exploitation code is available to interested parties.
Date: Thu, 17 Mar 2011