Update kernel and all server packages

Attackers often use old well-known bugs to compromise your server infrastructure. To make sure your server is not running on old packages, you should periodically update all packages. Even when you buy a new server from any hosting company, it is built with quite old OS packages and therefore first thing after the order should be to update all server packages to make sure you are running the most up to date and stable components.

On Centos operating system you can do it by calling command:

yum update