DexterJS: robust testing platform for DOM-based XSS vulnerabilities

Abstract

DOM-based cross-site scripting (XSS) is a client-side vulnerability that pervades JavaScript applications on the web, and has few known practical defenses. In this paper, we introduce DEXTERJS, a testing platform for detecting and validating DOM-based XSS vulnerabilities on web applications. DEXTERJS leverages source-to source rewriting to carry out character-precise taint tracking when executing in the browser context—thus being able to identify vulnerable information flows in a web page. By scanning a web page, DEXTERJS produces working exploits that validate DOM-based XSS vulnerability on the page. DEXTERJS is robust, has been tested on Alexa’s top 1000 sites, and has found a total of 820 distinct zero-day DOM-XSS confirmed exploits automatically.