Started off by
- Enabling unattended updates
- Enable only ssh login with key
- Create user with sudo privileges
- Disable root login
- Enable ufw with necessary ports
- Disable ping
- Change ssh default port 21 to something else.
Got the ideas from networkchuck
Did this on the proxmox host as well as all VMs.
Any suggestions?
Unattended updates can be tricky.
Think of config changes which need manual adjustment, or a broken update. This is something you would probably not like to happen at night without notice. Could easily break your vital systems (e.g. homeassistant, authentication, vaults...)
+1
Use unattended updates ONLY for bug and security fixes, nor for minor or major releases. Ensure you configure your auto-updaters properly!
Debian
unattended-upgrades
only upgrades packages from the main and security repos by default, so it should be fine since no major updates are performed within a particular Debian version.