I will secure your Server against the below security concerns.
The below security point will secure your server 99% on server to prevent unauthorized login, protection against brute-force attacks and also general Linux security improvement through the additional security point taken.
The following point will be taken:
SSH port change to custom one so that no one can find ssh port using nmap
Securing cPanel and WHM Access means force redirection to https access
I will setup ssh-keygen to login server ( if you required )
configure to enforce cPanel client usage strong passwords
kernel level patch and upgrade kernel if required
ssh login alert to your mail id
Disable ssh login for other user and configure other shell
Install maldet , rkhunter and chkrootkit to secure against library changed , root Shell kit and mail to complete report ( in extra gig )
Securing Apache and PHP ( in extra gig )
Install firewall and mod_scurity rules ( in extra gig )
secure ftp server ( in extra gig )
Tweak settings of cPanel
install and configure ClamAv for spam protraction ( in extra gig )
For do all things , i will required ssh access of your server
I will secure your cPanel server with many levels.