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?
Enabling unattended updates -> Hell no. Regular Patchdays
Enable only ssh login with key -> yes
Create user with sudo privileges -> yes
Disable root login -> no
Enable ufw with necessary ports -> Basic iptables, but not on all hosts. But fail2ban
Disable ping -> nope
Change ssh default port 21 to something else. -> nope
Remember to configure fail2ban, the defaults are silly.
Also, these days I prefer crowdsec to fail2ban.
Can you give me ressources on how to configure f2b?
I usually leave the defaults, or maybe tweak the times a bit.
One could only enter my network thru vpn or nginx on 443 anyway, so I am not that worried
The majority of the default fail2ban installations only bans an IP for 10 minutes and uses a 10 minute findtime, e.g. slow brute forcing is not at all banned.
Before I switched to crowdsec (which I really recommend you do, its quite easy) I changed my bantime and findtime in /etc/fail2ban/jail.conf (I think I made a local file... read the file it should say) to something like 8 hours (e.g. change 10m to 640m for both those variables).
Well if you are using strong passwords or no passwords from outside at all, but key auth only, i think you are pretty in the safe side. As i said, i have no ssh port open to the internet. Raising the ban time could only lead to banning myself. ๐
But for ports open to the outside, yes. I ppbly would do that too. Plus hardening the ssh config a bit
I have an open ssh port and I use key auth with password as well as crowdsec. Even if people get my ssh key they would still need to know the password.