I have an old server with Ubuntu server and Apache2 installed. I am using it to run a small one page site. I am using 'freenoms' for the free domain 'musicmash.tk' which is connecting to my public IP. The router is just a simple ISP one which is forwarding the server's port to for HTTP (which i think is 80). I am not concerned if someone can wipe the server so much as gain access to the rest of the network (like Samba shares). Should I be concerned about security? Is there anything I can easily do to increase security?
If you only have port 80 forwarded you shouldn't be much concerned, but it depends on your webserver. For instance if you have websait with mysql you should always use strong passwords and instal mod_security because there are many sql injection methods that if they succeed, the attacker will gain access to your ubuntu server (i assume it is on the local network, so this is a potential risk). Also install some firewall to prevent bruteforcing and to monitor activity on the server (access, system file changes etc.). I am currently pleased with csf/lfd, but this is on centos and i am not sure how it works on ubuntu.
IMHO you should pay great attention to those points at least:
- be very careful about software security updates to have vulnerabilities patched as they are discovered, especially around Apache and public web apps you can run on (blog, wiki ...)
- prefer to use non-standard tcp ports to be a bit less targetted by bots
- disable ping answers on your modem
- be very very careful about smart scripts running on your server (php, cgi, upload forms, etc), the lesser the better, the more restrictive the better
You can also set up a firewall with white list rule set like limiting public output traffic to be initiated by incomming tcp requests on your http listening port and incoming public traffic limited to your http destination port, deny new outgoing tcp connections. Using armor or selinux is a good idea too.