A website defacement is an attack on a website that changes the visual appearance of the site or a webpage.
These are typically the work of system crackers, who break into a web server and replace the hosted website with one of their own.
The most common method of defacement is using SQL Injections to log on to administrator accounts.
Defacements usually consist of an entire page. This page usually includes the defacer’s pseudonym or “Hacking Codename.” Sometimes, the Website Defacer makes fun of the system administrator for failing to maintain server security. Most times, the defacement is harmless, however, it can sometimes be used as a distraction to cover up more sinister actions such as uploading malware or deleting essential files from the server.