The Linux operating system has two default levels of security.

Level 1

To access a Linux workstation, users must supply a Login ID and password. Without these the user cannot access any part of the system.

Users should be instructed to keep their passwords confidential. This is because if a person with malicious intent gets a users password, they can use it to log on and damage the system.

Level 2

Once a user is logged on to the system they do not have access to everything because the files and directories are protected by permissions. These permissions (discussed in detail later in this chapter) are: read, write and execute.

Files and directories are automatically protected by permissions when they are created.

Example:

The following example shows the default permissions for a directory and a file:

drwxr-xr-x 2 chuck peanuts 102 Oct 29 05:50 Snoopy
-rw-r--r-- 1 chuck peanuts 612 Oct 29 05:55 lucy