In a general sense, hardening is the process of securing a computer. More specifically, hardening is the removal or disabling of all components in a computer system that are not necessary to its principal function or functions. By reducing the purposes for which a computer is used, the computer is rendered less vulnerable to outside attack by hackers or other intruders.
General hardening steps include limiting the number of users allowed to access a computer, tightening password and access control, and installing basic intrusion-detection software. The more specific variety of hardening requires the involvement of a highly trained computer technician. Once the user has defined the principal purpose or purposes for which the computer is to be used, then the technician can disable or remove all components that are not necessary to those purposes.
An example of a computer that needs to be hardened is a server, a computer, or device on a network (a group of linked computers) that manages network resources. The server should be equipped with high-quality firewall software to prevent outside intrusion. Often, such software may not provide enough security, in which case hardening is necessary. If the server is properly hardened, this narrows the avenues of access for intruders hoping to get past the server to other computers on the local network.
During the hardening process, a computer should be disconnected from any network. Once it is hardened, the computer will no longer be a general-purpose machine, but will be usable only for the very specific purposes for which it has been designated. The more specific that purpose, and the fewer general-purpose features on the computer, the more difficult it will be for a would-be intruder to access the computer, or to use it effectively once it has been accessed.
█ FURTHER READING:
Akin, Thomas. Hardening Cisco Routers. Sebastopol, CA: O'Reilly, 2002.
Connolly, P. J. "Fight DDoS Attacks with Intelligence." InfoWorld 23, no. 39 (September 24, 2001): 58.
Levine, Bernard. "What's Next for Electronics?" Electronic News 47, no. 40 (October 1, 2001): 1.
Wang, Wallace. "Hardening Your System." Boardwatch 15, no. 8 (June 2001): 44–46.