Black Hat Briefings, Usa 2007 [audio] Presentations From The Security Conference.

Several protection techniques based on run-time taint analysis have been proposed within the last 3 years. Some of them provide full-automated protection for existing web applications, others require human interaction, and yet others require source code modification and/or special tunning. We briefly discuss advantages and disadvantages of these approaches. Next, we introduce a new technique which permits to efficiently identify and block several attack vectors on the fly by augmenting the web application's execution environment to include tracking information. Most web-scripting languages including PHP, ASP, Python, Perl and Java can be protected with this technique. Typical exploitation methods such as database-injection attacks, shell injection attacks, cross-site scripting attacks and directory-transversal attacks are prevented. More generally, this solution to the injection vulnerability problem for web applications is based on a characterization of the injection attacks family -that we implemented. T