If you own a web server with cPanel and WHM, and you wish to further strengthen the security in order to mitigate unauthorised access to accounts (or, more importantly, the root account via WHM), you can add a safety net by enabling “Security Questions”.
Simply log in to WHM, and search for “Security Questions” (or go to Security Center -> Security Questions where you are able to enable this security provision).
Bear in mind this will also affect every cPanel account on the server, so if you have any customers with a cPanel account, they will need to add security questions the next time they login to their cPanel account.
While there are even more stringent security provisions you can implement, for example by disallowing access to the SSH service or the MySQL service to anything other than verified IPs (via the Host Access Control section of WHM), this in itself is a good security implementation irregardless.