Welcart e-Commerce <= 2.8.5 - Authenticated (Subscriber+) Information Disclosure and PHAR deserialization

The Welcart e-Commerce plugin for WordPress is vulnerable to Information Disclosure due to missing capability checks on the wel_check_progress_ajax AJAX action in versions up to, and including, 2.8.5. This makes it possible for authenticated attackers, with subscriber-level privileges or higher, to read certain log files maintained by the plugin leading to information disclosure. While the log file names are known and are directly accessible via browser on a server that is configured to serve .txt and .log files, the vulnerability allows attackers to access log files on other sites sharing the same server and also provides the ability to read such log files even if direct access is forbidden. Furthermore, the plugin is vulnerable to deserialization of untrusted input via the 'progressfile ' parameter. This makes it possible for attackers to call files using a PHAR wrapper, granted they can trick a site administrator into performing an action such as clicking on a link, that will deserialize and call arbitrary PHP Objects that can be used to perform a variety of malicious actions granted a POP chain is also present. It also requires that the attacker is successful in uploading a file with the serialized payload.