Physical Security Recap

By no means have we covered all of physical security in this brief introduction. Professionals become experts at individual aspects, such as fire control or power provision. However, this section should have made you aware of the major issues in physical security. We have to protect the facility against many sorts of disasters, from weather to chemical spills and vehicle crashes to explosions. No one can predict what will occur or when. The physical security manager must consider all assets and a wide range of harm.

Malicious humans seeking physical access are a different category of threat agent. With them, you can consider motive or objective: Is it theft of equipment, disruption of processing, interception of data, or access to service? Fences, guards, solid walls, and locks will deter or prevent most human attacks. But you always need to ask where weaknesses remain; a solid wall has a weakness in every door and window.

The primary physical controls are strength and duplication. Strength means overlapping controls implementing a defense-in-depth approach so that if one control fails, the next one will protect. People who built ancient castles practiced this philosophy with moats, walls, drawbridges, and arrow slits. Duplication means eliminating single points of failure. Redundant copies of data protect against harm to one copy from any cause. Spare hardware components protect against failures.