

You should turn off ssh password logins on external facing servers at a minimum. Only use ssh keys, install fail2ban, disable ssh root logins, and make sure you have a firewall limiting ports to ssh and https.
This will catch most scripted login attempts.
If you want something more advanced, look into https://en.m.wikipedia.org/wiki/Security_Technical_Implementation_Guide and try to find an ansible playbook to apply them.
Wait until they find out about Ansible.