Custom Content Type Manager (CCTM) is a relatively popular plugin with three years of development, 10,000+ active installs, and a satisfaction rating of 4.8. It helps create custom post types. Website owners find the classical “blog format” too restrictive, use the plugin to add custom elements to their posts. So far so good.
This week we cleaned one infected site and found a very suspicious auto-update.php file inside wp-content/plugins/custom-content-type-manager/.
https://blog.sucuri.net/2016/03/when-wordpress-plugin-goes-bad.html