------------------------------------------------------------------------ Cross-Site Scripting in Activity Log WordPress Plugin ------------------------------------------------------------------------ Yorick Koster, July 2016 ------------------------------------------------------------------------ Abstract ------------------------------------------------------------------------ A Cross-Site Scripting vulnerability was found in the Activity Log 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-20160724-0022 ------------------------------------------------------------------------ Tested versions ------------------------------------------------------------------------ This issue was successfully tested on Activity Log [2] WordPress Plugin version 2.3.2 ------------------------------------------------------------------------ Fix ------------------------------------------------------------------------ This issue is fixed in Activity Log version 2.3.3 [3] ------------------------------------------------------------------------ Introduction ------------------------------------------------------------------------ The Activity Log [2] WordPress Plugin helps monitor & log all changes and activities on a WordPress site. A Cross-Site Scripting vulnerability was found in the Activity Log 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 classes/class-aal-admin-ui.php and is caused by the lack of output encoding on the page request parameter. The vulnerable code is listed below. public function activity_log_page_func() { $this->get_list_table()->prepare_items(); ?>

get_list_table()->display(); ?>
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 ------------------------------------------------------------------------
------------------------------------------------------------------------ References ------------------------------------------------------------------------ [1] https://sumofpwn.nl/advisory/2016/cross_site_scripting_in_activity_log_wordpress_plugin.html [2] https://wordpress.org/plugins/aryo-activity-log/ [3] https://downloads.wordpress.org/plugin/aryo-activity-log.zip