I've secured SSH on my server (key authentication, no rootlogin, protocol 2, etc), but I'm a bit paranoid.
I cannot use some ip filter since I want to keep flexibility as to from where I can login myself.
I'm thinking about sending an email to myself when someone logs into my system using SSH.
However this makes me wonder:
Let's say I have the above implemented and I get an email that someone just logged in using SSH. And I know for sure it isn't me :) nor is it another admin.
What would be the appropriate response?
- Bring the server down in panic?
- Monitor what the malicious user is doing on the server?
- Kick out the user?
- Kill it with fire?
- Something else?
Server is Centos 5.7
The server is used as a webserver (Apache/Postgres/PHP) and mailserver (Zimbra).
So I guess the data is mails and databases.