Over the years I have had to harden a great number of LAMP boxes, I have found some methods work for better than others. I will now share with you all my favorite 10 along with methods to implement them on Debian/Ubuntu.

10. Lock SSH access right down. I do this by disabling root logins, disabling password authentication and using denyhosts.

To disable root logins do this: vi /etc/ssh/sshd_config and look for the following line: PermitRootLogin yes and change it thus: PermitRootLogin no

To disable password authentication (you will have to use public/private keys) do this: vi /etc/ssh/sshd_config and look for the following line: #PasswordAuthentication yes (note its commented out) and change it thus: PasswordAuthentication no

To install denyhosts do this: apt-get install denyhosts once installed it shouldn't need any configuration, but you can tweak the settings if you wish in /etc/denyhosts.conf

9. Always use Sudo for root access, This is one of the things Ubuntu does really well and its about time other distros did the same.