tssci security

Path X -- Explosive Security Testing

We have received details from ShmooCon with the scheduled day and time of our talk. We have been scheduled for the last talk on Sunday at 12pm noon (before the room split) on the "Build It" track. I'm not sure whether that's a good thing or bad thing, but we'll see. We're excited about the research we've done thus far -- we haven't seen much being done in this area, and we hope you see the value in it all. Check out the ShmooCon schedule and speakers list for the full schedule and list of all presentations and bios.

In this talk, we'll discuss how using XPath can aid security testing during unit tests and in the integration phase of the software development lifecycle. By using XPath, it's easier to share data between both open source and commercial quality testing, source code analysis tools and web application scanners.

First we'll go over a little history behind using regex in security tools and the paradox of parsers both being a vulnerability problem and a solution. Later, we'll explain XPath and how it's used in testing and then some XML parsing implementations in various languages. We'll close out our talk with a discussion on web application security internals, and how you can begin to [with relative ease] write your own web application security scanners.

"So all this talk about XPath without even mentioning what it is or what it does," you say? Well, XPath isn't really a tool. Tools use XPath to locate elements in web pages. Other ways of locating elements in a web pages is using DOM (Document Object Model) selectors or CSS selectors. An example of each is shown below, which would select the <h1> element within the <div id="header">:

DOM:
document.getElementById('header').getElementsByTagName('h1');
CSS:
div#header>h1
XPath:
//div[@id='header']/h1

So how do I use XPath? How does it apply to security? Those who've read Secure Programming with Static Analysis by Brian Chess and Jacob West would make the connection to using abstract syntax trees and lexical analysis to identify software vulnerabilities. In our talk, we look at using XPath expressions to find flaws in web applications.

Posted by Marcin on Sunday, February 17, 2008 in Conferences and Security.

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