Generally means to mar or alter a Website in some undesirable way. Because most Web servers are vulnerable to being exploited, they are often compromised by crackers who replace the information on Web pages with other information to their liking.

One particular Website at http://www.attrition.org/mirror/attrition/ lists various sites that have been defaced—an item that they call “the defacement mirror.” However, a note on this attrition Website currently says that what began as a rather tiny collection of Website defacement mirrors soon turned into a massive 24-hour-a-day, seven-day-a-week project. By 2001, says this note, a single day’s mirroring included more than 100 defaced Websites—more than three times the total mirrored for 1995 and 1996. By May 2001, maintaining “the mirror” became a full-time, thankless chore, so the sponsors stopped the activity. Today’s Website features what had been there as of May 21, 2001.

See Also: Crackers; Cracking.