WPC Shop as a Customer for WooCommerce <= 1.2.8 - Authentication Bypass Due to Insufficiently Unique Key

The WPC Shop as a Customer for WooCommerce plugin for WordPress is vulnerable to account takeover and privilege escalation in all versions up to, and including, 1.2.8. This is due to the 'generate_key' function not producing a sufficiently random value. This makes it possible for authenticated attackers, with Subscriber-level access and above, to log in as site administrators, granted they have triggered the ajax_login() function which generates a unique key that can be used to log in.