NAVEX: Precise and Scalable Exploit Generation for Dynamic Web Applications

Modern multi-tier web applications are composed of several dynamic features, which make their vulnerability analysis challenging from a purely static analysis perspective. We describe an approach that overcomes the challenges posed by the dynamic nature of web applications. Our approach combines dynamic analysis that is guided by static analysis techniques in order to automatically identify vulnerabilities and build working exploits. Our approach is implemented and evaluated in NAVEX, a tool that can scale the process of automatic vulnerability analysis and exploit generation to large applications and to multiple classes of vulnerabilities. In our experiments, we were able to use NAVEX over a codebase of 3.2 million lines of PHP code, and construct 204 exploits in the code that was analyzed.