Security hardening is the process of making a system harder to abuse by removing unnecessary software, disabling unused services, tightening permissions, and enforcing safer defaults. The goal is to shrink the attack surface so that a compromise requires more effort, more privileges, or a second weakness. Hardening is central to cyber defense because many intrusions start by exploiting exposed features that were never needed in the first place.
In practice, hardening appears in endpoint lockdowns, VDI and thin-client configurations, server baseline templates, and application allowlists. Defenders may restrict local admin rights, close management ports, enforce strong authentication, and keep firmware and operating systems updated. Attackers benefit when hardening is weak: a low-privilege local foothold can become a path to unauthorized access if UI features, services, or permissions are left broader than necessary.