Chapter 14 Linux Security 435

Your company’s data is under your protection. Security threats can come from almost anywhere — a disgruntled employee, a hacker, or a rival company.

Network and system security is one of the greatest concerns facing the Linux system administrator.

Security threats arrive in many forms, such as physical theft of a system, a stolen password, or an attack from a remote network user in another country. These security threats can cost your company great amounts of money and time spent on recovering data or fixing a hacked system.

Implementing a proper security policy for your company — and having it backed by management — is integral to protecting your company’s systems and data. This chapter deals with implementing these security policies within the physical environment, and with the users, the system administrators, and the company’s data.

Securing the Environment

5.11 Perform and verify security best practices (e.g., passwords, physical environments)

5.12 Assess security risks (e.g., location, sensitive data, file system permissions, remove/disable unused accounts, audit system services/programs)

The physical security of your Linux system is one of the most overlooked areas in the creation of a secure environment. When planning the physical environment for your Linux system, you need to address some key issues in order to support your security policies.

Location

You don’t want your system sitting out in the open, where it may be damaged, vandalized, stolen, or tampered with. The best place to store your server is in a proper server room or a closet that can be locked. In large environments, many servers are individually locked in cages or server racks, along with the keyboard, mouse, and monitor, to prevent unauthorized people from attempting to access the system.

The server room area should be consistently monitored, and the log files containing information about who has entered and exited the room should be periodically examined for any strange behavior.

The locking device for this cage or closet can be any type, but the traditional method of using keys can be a drawback. For example, if an employee with access to the room leaves the company, the locks must be re-keyed — just in case that employee has made copies of the originals before turning them in. Keys are also easily lost, and therefore, must be replaced often. A better method for securing