Toward an SDN-Based Web Application Firewall:Defending against SQL Injection Attacks

Web attacks pose a significant threat to enterprises, as attackers often target web applications first. Various solutions have been proposed to mitigate and reduce the severity of these threats, such as web application firewalls (WAFs). On the other hand, software-defined networking (SDN) technology has significantly improved network management and operation by providing centralized control for network administrators. In this work, we investigated the possibility of using SDN to implement a firewall capable of detecting and blocking web attacks. As a proof of concept, we designed and implemented a WAF to detect a known web attack, specifically SQL injection. Our design utilized two detection methods: signatures and regular expressions. The experimental results demonstrate that the SDN controller can successfully function as a WAF and detect SQL injection attacks. Furthermore, we implemented and compared ModSecurity, a traditional WAF, with our proposed SDN-based WAF. The results reveal that our system is more efficient in terms of TCP ACK latency, while ModSecurity exhibits a slightly lower overhead on the controller.