404 Error Monitor <= 1.1 - Cross-Site Request Forgery to Plugin Settings Update via updatePluginSettings Function

Description

The 404 Error Monitor plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.1. This is due to missing or incorrect nonce validation on the updatePluginSettings() function. This makes it possible for unauthenticated attackers to make changes to plugin settings and clear up all the error logs via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.