Research on protection security problems in web applications

Web applications generally have a result-oriented and rapid development process. At the development time, security criterion ignored consciously or unconsciously. Therefore, it allows security vulnerabilities that will cause differently behave the developed applications than they should behave. These vulnerabilities in developed web applications provide an opportunity for malicious users. Another mistake made in the development web applications is that the security application's security is confused with the network layer's security. It should be known that Firewall (security gateway) does not protect web applications. Therefore, it is absolutely necessary to conduct infiltration and safety tests for the developed applications. The above mentioned weakness and the presence of malicious users causes some risks on the system. These risks can also spread to other users on the system. We can give the definition of risk as follows: Risk = Threat + Vulnerability The goal of writing thesis is that to handle the current weakness in the web applications, to learn what are the thoughts and approaches that cause these weaknesses to occur, what alternatives can be made to these approaches and what measures can be taken to eliminate weaknesses. Keywords: Web Application Security, SQL Injection, Cross Site Request Forgery, Cross Site Scripting, Secure Socket Layer, Same Origin Policy.