Mozilla to Release JavaScript Fuzzer for Firefox

The home-brewed JavaScript fuzzer used to poke holes in Firefox is the first in a series of tools for the open-source community.

Mozilla has distilled what its learned from pounding its Firefox browser and will release its home-brewed knowledge in a series of open-source tools, the first of which is a JavaScript fuzzer that will be released at the Black Hat conference in Las Vegas Aug. 2.

Security chief Window Snyder will detail the "gory details" of how Mozilla gets security done—something you dont get out of a traditional vendor, she told eWEEK in an interview. "[At] Mozilla, the whole worlds watching—we couldnt hide if we wanted to," Snyder said.

Before she came to work for Mozilla, Snyder was a security consultant. She said she saw people constantly reinventing the wheel in terms of security testing processes, tools or how to get a baseline. One thing she came away with: Smaller environments that cant afford a human security professional are struggling to get security information.

So when she got to Mozilla, Snyder decided to make things better for those frantic people. "At Mozilla, since the whole world can see what were doing, [we thought] maybe we can package it up, make it available, get some feedback on it, have people contribute, and have other projects use them," she said.

The JavaScript fuzzer Mozilla plans to release Aug. 2 has found dozens of vulnerabilities in Firefox. The tool can be modified, built on and used with any technology that employs JavaScript, Snyder said.

"Thats our hope, that people might find it useful," Snyder said.

A fuzzer is a tool that sends data to an application in ways that the application might not expect. A fuzzer can run through test cases—in some cases millions of test cases—with combinations of data and fields manipulated in many ways. The tool by itself isnt dangerous, but it can be used to find where unexpected behavior is in input validation—a useful clue to identifying a vulnerability.

Mozilla also plans to release a protocol fuzzer for HTTP on the client side and a fuzzer for FTP, also from the client side, in a few months, and still more tools after that.

/zimages/3/28571.gifClick here to read about serious URI-handling holes in Firefox that, if left unpatched, leave a system open to hijacking.

Mozilla already shared the JavaScript fuzzer in May with companies whose products Mozilla thinks are vulnerable from relevant risks, wanting to get it into the big vendors hands before letting the world know what it knows about how to bring their products down. That includes Apple, Microsoft and Opera.

Only one company thanked the open-source foundation. None has given Mozilla the feedback it would be grateful to hear regarding whether the tool was useful, Snyder said.

At her Black Hat presentation, Snyder will give more details on the JavaScript fuzzer, including a description of the process Mozilla goes through and how the security team weeds out bugs. Snyder also plans to detail the security features of the upcoming Firefox 3.0 release, due in the fall.

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