An improved filter against injection attacks using regex and machine learning

Injection-based attacks have consistently made the Open Web Application Security Project (OWASP)Top 10 vulnerabilities for years. 1 Common types of injection attacks include SQL injection, cross-site scripting (XSS) and code injection. Filter engines are used to detect and sanitise user inputs for these malicious attacks. The user input is assumed to be tainted by default. Thus, the ability of a filter in terms of accuracy and latency is important. There exist various approaches to improve filters, primarily including techniques based on regular expressions (regexes), abstract syntax tree, machine learning and so on. However, the testing of modern solutions has achieved no more than 98.5% accuracy for XSS. This article looks at ways to improve accuracy.