Here’s a list of security programs I usually install on our root-servers. Better install now, before you have a compromised system and you can’t tell what exactly happened:

• snoopy – logs sheel commands via execve()
• tiger – security audit for linux systems
• chrootkit – checks for rootkits
• checksecurity – basic system checks
• munin – tiny and fine; the plugin interface is very easy
• mod_security – Security Module for Apache
• debsecan – checks your installed packages for security problems
• vnstat – Network traffic monitor
• htop – Better top
• mtop – The same for MySQL
• ntpdate - Server ought to have to right time!

If anyone know other good tools suggestions are welcome. And don’t forget to enable apache logging