Server security commands:

1) Make Sure No Non-Root Accounts Have UID Set To 0
awk -F: ‘($3 == “0”) {print}’ /etc/passwd

2) Disable Unwanted Services
Type the following command to list all services which are started at boot time in run level # 3:
chkconfig –list | grep ‘3:on’

3) Find Listening Network Ports

Use the following command to list all open ports and associated programs:
netstat -tulpn

4) OR
nmap -sT -O localhost
nmap -sT -O server.example.com

5) World-Writable Files

Anyone can modify world-writable file resulting into a security issue. Use the following command to find all world writable

and sticky bits set files:
find /dir -xdev -type d \( -perm -0002 -a ! -perm -1000 \) -print

6) Noowner/nobody Files

Files not owned by any user or group can pose a security problem. Just find them with the following command which do not

belong to a valid user and a valid group
find /dir -xdev \( -nouser -o -nogroup \) -print