A method for detecting code security vulnerability based on variables tracking with validated-tree

SQL injection poses a major threat to the application level security of the database and there is no systematic solution to these attacks. Different from traditional run time security strategies such as IDS and firewall, this paper focuses on the solution at the outset; it presents a method to find vulnerabilities by analyzing the source codes. The concept of validated tree is developed to track variables referenced by database operations in scripts. By checking whether these variables are influenced by outside inputs, the database operations are proved to be secure or not. This method has advantages of high accuracy and efficiency as well as low costs, and it is universal to any type of web application platforms. It is implemented by the software code vulnerabilities of SQL injection detector (CVSID). The validity and efficiency are demonstrated with an example.