Mozilla patches Firefox's critical Pwn2Own bug

Ships 'fire-drill' security update 5 days early, beats Microsoft, Apple to the patch punch

Mozilla Corp. patched two critical Firefox bugs on Friday, including one used the week before by a German student to win $15,000 for hacking three different browsers at the Pwn2Own contest.

Firefox 3.0.8 was released several days earlier than expected. As recently as Thursday, Mozilla had set April 1 as the ship date for what the company labeled a "high-priority fire-drill security update" that would fix not only the Pwn2Own bug, but another that was revealed last Wednesday.

Both vulnerabilities were rated critical by Mozilla, But the most notable was clearly the one exploited earlier this month at CanSecWest, the Vancouver, British Columbia security conference that hosts the Pwn2Own hacking challenge.

At the contest, a 25-year-old computer science student from Germany who would only give his first name as Nils hacked Firefox and Safari on an Apple Inc. notebook, as well as Microsoft Corp.'s Internet Explorer 8 running on Windows 7. Nils was paid $5,000 for each successful exploit by 3Com Inc.'s TippingPoint, the Pwn2Own sponsor.

According to Mozilla, Nils' bug is in XUL, Mozilla's XML user interface markup language. In some cases, the "_moveToEdgeShift" tree method crashed Firefox; that crash could then "be used by an attacker to run arbitrary code on a victim's computer," Mozilla concluded.

Mozilla restricted access to additional information on the vulnerability by locking down Bugzilla, its bug tracking and management database, allowing only authorized users to view more information on the flaw.

Firefox 3.0.8 also patched a critical vulnerability that had gone public on the milw0rm.com exploit site last Wednesday. The bug allowed an attacker to crash Firefox by using malicious XSL code embedded on a Web site. "An attacker could potentially use this crash to run arbitrary code on a victim's computer," Mozilla warned in the accompanying security advisory.

The new version of Firefox can be downloaded for Windows, Mac OS X and Linux from the Mozilla site. Current users can also call up their browsers' built-in updater, or wait for the automatic update notification, which should pop up within 48 hours.

As expected, Mozilla beat rivals Microsoft and Apple Inc. by patching its Pwn2Own vulnerability first. Although the exploit Nils used to hack IE8 Release Candidate 1 (RC1) has been blocked by the final version of the browser -- it shipped a day after Pwn2Own -- the underlying flaw has not been fixed, and can be leveraged by attackers against Windows XP, according to TippingPoint's manager of security response, Terri Forslof.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Gregg Keizer

Computerworld
Show Comments

Father’s Day Gift Guide

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Luke Hill

MSI GT75 TITAN

I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?