Manipulating Web Application Interfaces, A New Approach To Input Validation presented at OWASP Appsec 2009

by Felipe Moreno (Ernst & Young ),

Tags: Security Web Application Security Browser

URL :,_a_new_approach_to_input_validation

Summary : This talk will suggest a new approach for web application input validation testing and introduce Groundspeed, an open-source Firefox extension that manipulates the interface of web applications in order to make the life of the security tester easier. Today, most of the manual parameter manipulation tests in web applications are performed using tools that modify the raw HTTP requests sent to the server. While this approach works best on simple applications, it is often inappropriate for more complex applications. Groundspeed is a Firefox extension that allows the security tester to modify the application user interface by manipulating the forms and form elements, eliminating annoying limitations and client-side controls. Some of the practical uses of Groundspeed include changing all hidden fields into text fields, removing size limitations on input fields and modifying JavaScript event handlers to bypass client side validation without actually removing it. The extension works by dynamically modifying the Document Object Model (DOM) of the page after Firefox has finished loading and rendering it. The changes take effect immediately and, since it happens entirely on the client side without generating new requests to the server, it is completely transparent to the application. More information, including a link to download and install groundspeed is available here:

Felipe Moreno: Felipe Moreno is a manager at the Ernst & Young Advanced Security Center (ASC), based in New York City. He has more than 8 years of information security experience performing application security reviews and penetration tests in addition to teaching secure coding classes to Fortune 500 clients both in the US and Europe.