What are the 7 layers of security?

The 7 layers of security refer to a defense in depth model used in cybersecurity and physical security to protect systems by layering multiple defenses so if one fails another protects. While models vary, a common 7 layer model for IT security includes Layer 1 Physical Security, protecting buildings, servers, and devices from theft and damage. Layer 2 Perimeter Security including firewalls and intrusion prevention. Layer 3 Network Security including network segmentation, VPNs, and monitoring. Layer 4 Endpoint Security protecting computers, phones, and devices with antivirus and encryption. Layer 5 Application Security including secure coding, patching, and web application firewalls. Layer 6 Data Security including encryption, access controls, and data loss prevention. Layer 7 Human Layer including security awareness training, policies, and human factor, often considered weakest link. Another physical security model lists deterrence, detection, delay, defense, denial, decontamination, and debrief. The concept is that no single layer is foolproof, so layering provides redundancy, and attacker must defeat multiple layers to reach asset. This layered approach is fundamental to modern security strategy.