Certified: The Security+ Prepcast

In this episode, we are going to shift our focus back to the physical world and explore the essentials of physical security. While cybersecurity often brings to mind firewalls and encryption, it is important to remember that physical access to systems is one of the most direct and dangerous paths an attacker can take. If someone can physically access your devices, networks, or storage, they can bypass many of your digital defenses in seconds.
Physical security must be integrated with digital strategies to create a complete defense-in-depth approach. This means considering physical protection as one more layer of security, working in harmony with firewalls, access controls, and encryption. In high-security environments, digital and physical systems are deeply connected—badge readers may link to network access controls, cameras may integrate with system logging, and physical presence may be a factor in authentication.
Within any comprehensive security framework, physical security plays a foundational role. If you cannot secure the buildings, rooms, and infrastructure that house your digital systems, your other protections are significantly weakened. A strong physical security program not only reduces risks related to theft and sabotage but also supports compliance with industry regulations that require access controls and audit readiness.
Physical security helps mitigate a wide range of threats. These include unauthorized access, theft of equipment, tampering with network devices, and even environmental sabotage like disabling cooling systems. Without physical controls, a determined attacker could unplug a server, clone a hard drive, or install a rogue device with little effort. With proper controls in place, these threats can be detected, deterred, or completely blocked.
Let’s explore some of the major components of a physical security system, starting with entry control. Entry control refers to the methods used to restrict who can enter a secure area. Bollards are short, sturdy posts placed in front of entrances to prevent vehicles from driving into buildings. While simple, they are effective at stopping both intentional and accidental threats. Access control vestibules, also known as mantraps, are small spaces with two sets of locked doors. A person must be verified and approved before being allowed to move from the outer door to the inner door. These vestibules help prevent tailgating and unauthorized entry.
Perimeter defenses are the first line of physical security. Fencing around the facility helps define boundaries and delay intruders. It may include barbed wire or sensors to detect movement. Video surveillance systems monitor the perimeter in real time or record footage for later review. These cameras serve both as a deterrent and as a detection tool. In many cases, the presence of visible cameras is enough to stop suspicious activity before it begins.
Human controls are another important component. Security guards provide flexible, real-time protection that automated systems cannot always deliver. They can verify identities, respond to incidents, and enforce access policies. Badge systems help guards and automated systems confirm whether a person is authorized to enter a space. These badges can be programmed with access levels, time-of-day restrictions, and logging features that track movement throughout a facility.
Deterrents are used to influence behavior by making security measures visible and obvious. Strategic lighting is one of the most effective deterrents. Well-lit areas reduce hiding spots and increase the chance that an intruder will be seen. Lighting should be placed near entry points, around fences, and along paths commonly used at night. Visibility management is also key—removing obstructions and keeping camera views clear helps make surveillance effective and reduces blind spots.
Detection technologies support both deterrence and response. Infrared sensors detect heat signatures and are commonly used in motion detectors. Pressure sensors can detect when someone steps on a surface or opens a door. Microwave sensors use radio waves to detect movement, often in large or open areas. Ultrasonic sensors use high-frequency sound waves to detect motion and are often used in indoor spaces. Each of these sensor types has unique strengths, and many organizations use a combination to provide full coverage of a secure area.
Together, these components create a layered physical security posture that protects assets, enforces access controls, and supports digital systems. A secure server room may be protected by a locked door with badge access, monitored by cameras, and located within a building protected by fencing, guards, and surveillance. Add lighting, alarms, and detection sensors, and the result is a physical space that strongly supports cybersecurity goals.
For the Security Plus exam, be ready to identify physical security controls and match them to their functions. Know the difference between deterrents, detection tools, and entry controls. Understand how physical security works alongside digital controls to protect systems and data. Practice recognizing the names and uses of specific technologies like bollards, infrared sensors, and badge readers. The exam may describe a scenario where physical security is the weak link—and your job will be to spot the control that would fix it.