Internet connects around three billions of users worldwide, a number increasing every day. Thanks to this technology, people, companies and devices perform several tasks, such as information broadcasting through websites. Because of the large volumes of sensitive information and the lack of security in the websites, the number of attacks on these applications has been increasing significantly. Attacks on websites have different purposes, one of these is the introduction of unauthorized modifications (defacement). Defacement is an issue which involves impacts on both, system users and company image, thus, the researchers community has been working on solutions to reduce security risks. This paper presents an introduction to the state of the art about techniques, methodologies and solutions proposed by both, the researchers community and the computer security industry.