Academic Paper from the year 2018 in the subject Computer Science - IT-Security, grade: 10, , course: Master thesis, language: English, abstract: Modern web applications have higher user expectations and greater demands than ever before. The security of these applications is no longer optional; it has become an absolute necessity. Web applications contain vulnerabilities, which may lead to serious security flaws such as stealing of confidential information. To protect against security flaws, it is important to understand the detailed steps of attacks and the pros and cons of existing possible solutions. The goal of this paper is to research modern web application security flaws and vulnerabilities. It then describes steps by steps possible approaches to mitigate them.