Within the last years the commercial relevance of web applications increased steadily. They developed from simple information sharing platforms to serious business applications like online-banking, e-commerce and social media platforms. Unlike most other technologies, web-based applications are accessible from around the world continuously. Additionally, they are very susceptible for vulnerabilities as there are various technologies interacting. These factors render web applications to very attractive targets for criminals because they are often easy to attack, globally accessible and yield valuable exploits. As a consequence, much e?ort was put into research to prevent, detect and eliminate web application vulnerabilities. However manual security audits are time-consuming, costly and demand expertknowledge. Web vulnerability scanners tackle this problem. They are programs that test web applications for the existence of vulnerabilities. Additionally they categorize and report them. Because these tools work automatically, faster as humans and reduce the necessary knowledge in network security, they became an interesting supplementation to traditional security audits. On the other side web vulnerability scanners also have their limits. They can not test for the absence of vulnerabilities and thus produce false positives or miss weaknesses. Furthermore previous research has shown that there are also vulnerability classes that are especially intricate to detect like stored SQL injections or stored cross-site scripting vulnerabilities. Nonetheless web vulnerability scanners show very much potential and there is a growing interest into automatic web application testing. This is re?ected in the increasing diversity of commercial web vulnerability scanners that can be found online. Thus this thesis compares and examines three web vulnerability scanners, namely Acunetix, Arachni and w3af. Focus is set on delineating the current capabilities and limits of state-of-the-art vulnerability scanners.