Linux Server Security Cheklist.

1. Keep the system Updated with Latest Security Patches
2. Keep Yourself updated with latest vulnerabilities through mailing lists, forums etc.
3.Disable and stop unwanted services on the server.
4.Use SUDO to limit ROOT Access
5. SSH security settings.
6. Check the integrity of critical files using checksum
7.Tunnel all of your X-Window Sessions through SSH.
8.Use SeLinux
10.Only create required no of users
11.Maintain a good firewall policy
12.Configure SSL/TLS if you are using FTP.
13.check file permissions accross filesystems.
14.Use tools like adeos for potential file state
15.Ensure sticky bit on /tmp Directory
16.check and lock users with blank passwords.
17. Bootloader and BIOS security
18.Give special attention to portmap related services
19.Deploy your NFS shares with Kerberos Authentication.
20.Enable remote Logging
21. Disable root Logins by editing /etc/securetty
22.Keep A good Pasword Policy.