Hackers claim zero-day flaw in Firefox

by admin October 1, 2006 at 2:45 pm

SAN DIEGO–The open-source Firefox Web browser is critically flawed in the way it handles JavaScript, two hackers said Saturday afternoon.

An attacker could commandeer a computer running the browser simply by crafting a Web page that contains some malicious JavaScript code, Mischa Spiegelmock and Andrew Wbeelsoi said in a presentation at the ToorCon hacker conference here. The flaw affects Firefox on Windows, Apple Computer’s Mac OS X and Linux, they said.

“Internet Explorer, everybody knows, is not very secure. But Firefox is also fairly insecure,” said Spiegelmock, who in everyday life works at blog company SixApart. He detailed the flaw, showing a slide that displayed key parts of the attack code needed to exploit it.

The flaw is specific to Firefox’s implementation of JavaScript, a 10-year-old scripting language widely used on the Web. In particular, various programming tricks can cause a stack overflow error, Spiegelmock said. The implementation is a “complete mess,” he said. “It is impossible to patch.”

The JavaScript issue appears to be a real vulnerability, Window Snyder, Mozilla’s security chief, said after watching a video of the presentation Saturday night. “What they are describing might be a variation on an old attack,” she said. “We’re going to do some investigating.”

Full story: CNET News.com