I had a problem that sometimes somebody hacked my password to my Linux server and run some programs on my Linux server. Every time when I decided to rebuild my Linux distribution on the server and change password to more crazy after a few months this happened
again – somebody hacked access to my Linux.
I
Go to file: /etc/ssh/sshd_config
Find a line with text: #PermitRootLogin yes
Change it PermitRootLogin no
Confirm with: sudo service ssh restart
Confirm with
Save and done.
https://mediatemple.net/community/products/dv/204643810/how-do-i-disable-ssh-login-for-the-root-user