A Symbolic Execution Framework for JavaScript

In Proc. of the 31st IEEE Symposium on Security and Privacy (Oakland 2010)


As AJAX applications gain popularity, client-side JavaScript code is becoming increasingly complex. However, few automated vulnerability analysis tools for JavaScript exist. In this paper, we describe the first system for exploring the execution space of JavaScript code using symbolic execution. To handle JavaScript code's complex use of string operations, we design a new language of string constraints and implement a solver for it. We build an automatic end-to-end tool, Kudzu, and apply it to the problem of finding client-side code injection vulnerabilities. In experiments on 18 live web applications, Kudzu automatically discovers 2 previously unknown vulnerabilities and 9 more than that were previously found only with a manually-constructed test suite.

Kaluza String Solver

Kaluza, a solver for strings, that we created as part of the project is described here, and is also available as an online demo.


This work has been awarded the AT&T Best Applied Security Research Paper Award 2010.