Hardening' within cybersecurity refers to the process of securing a system by reducing its surface of vulnerability. The vulnerable area is, by default, larger when a system performs more functions i.e. a single-function system is more secure than a multipurpose sysem.
Hardening methods can include:
- changing default passwords
- removing unnecessary features, software, unnecessary usernames or logins
- disabling or removing unnecessary services.
- applying patches
- closing open network ports
- setting up firewalls, intrusion detection systems and intrusion prevention systems