Device hardening is the practice of reducing an endpoint’s attack surface so it is harder to infect, control, or misuse. It usually includes changing default passwords, disabling unnecessary services, applying security updates, limiting exposed ports, enforcing least privilege, and turning on logging and secure configuration settings.
In cyber security, hardening matters because many attacks start with weak devices such as home routers, servers, and IoT equipment that are easy to scan and exploit. A hardened device is less likely to become part of a botnet, a relay for malicious traffic, or a foothold inside a network. Defenders use hardening in builds, baselines, and incident response to contain damage and make cleanup more reliable. The stronger the baseline, the fewer opportunities attackers have to persist or move laterally.