Securing your Linux server is a crucial step in protecting your data, intellectual property, and time, from the hands of crackers (hackers). The system administrator is liable for security Linux box. Lets start with this

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

You need to investigate each reported file and either set correct user and group permission or remove it.

Noowner 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

You need to investigate each reported file and either assign it to an appropriate user and group or remove it.