An approach for SQL injection detection based on behavior and response analysis

摘要

Nowadays the Internet is closely related to our daily life. We enjoy the quality of service the provided by The Internet at the same time, but also suffer from the threat of network security. Among the many threats, SQL injection attacks are ranked in the first place. SQL injection attack refers to “when the user sends a request to the server, the malicious SQL command will be inserted into the web form or request URL parameters, leading to the server to perform illegal SQL query. The existing SQL injection detection methods include static analysis, dynamic analysis, parameterized query, intrusion detection system, parameter filtering and so on. However, these methods have some defects. Static analysis method can only detect the type and grammatical errors of SQL. Dynamic analysis can only detect the vulnerability predefined by application developers. Parameter filtering is based on regular expressions and black list to filter invalid characters. This method needs predefined regular expressions, but due to the diversity of SQL syntax and user input, resulting in a regular expression can't meet the requirements of detection, and has the defects that the attackers bypass detection to inject by the way of encoding parameters. In this paper, we propose a new approach to detect and prevent SQL injection. Our approach is based on the attack behavior and the analysis of response and state of the web application under different attacks. Our method perfectly solves the problems existing in methods mentioned above, and has higher accuracy.