4. Microsegmentation

Microsegmentation is a security approach that divides an IT environment into smaller, tightly controlled segments. It uses detailed logical rules to limit which systems, users, services, or departments can communicate with each other.

This helps stop attackers from moving easily between systems after gaining access. Modern attacks often bypass static perimeter controls and spread inside the environment, so microsegmentation reduces that risk by containing movement.

It supports least privilege by allowing access only where it is specifically needed. For example, sensitive departments like HR can be isolated so other business units cannot access their data.

Microsegmentation is enforced through software and logical policies, not physical separation. Rules can be applied at a very granular level, such as by machine, user, IP address, time, credentials, or service type.

It is especially useful in data centers, cloud environments, shared infrastructure, virtualization, and software-defined networking. In cloud systems, similar controls are often implemented through tools like security groups or virtual network policies.

Main Idea
Microsegmentation limits internal communication in fine detail so attacks are contained, sensitive systems are isolated, and least-privilege access is enforced across the environment.