This bachelor’s thesis is focused in cyber security and the web-based vulnerabilities and stakeholders who participate in the exploitation as being the technical equipment, the attacker or the victim. The focus of this thesis is to first give the reader the picture about the cyber world and its stakeholders and after that give a picture about three different vulnerabilities that are common in the web services that we use every day. Exploiting these vulnerabilities is a crime and they are usually divided into two different categorize. There are cyber assistant and cyber dependent crimes. Cyber assistant crimes are crimes that can be done without the assistance of it-equipment like fraud in the second-hand markets of the internet. The cyber d...