Firefox 3.0 may Block Sites Fingered by Google

Sites that Google has determined to be housing malware would be blocked by a feature under discussion for the next major release of Firefox.

Mozilla Corp. is considering adding a tool to Firefox 3.0 that would automatically block Web sites thought to harbor malicious downloads, but the company's security chief refused to spell out details, saying Mozilla is "not ready to talk about the feature."

Even so, there are numerous details to be found on a blog by a Firefox designer and in a back-and-forth discussion of the feature in Bugzilla, the management system that Mozilla uses to track changes in its software. Together, the two offer a behind-the-scenes look into Mozilla's open-source development process.

"Similar to how Firefox 2 blocks Web sites that are potentially going to try to steal your personal information, Firefox 3 will block Web sites that we believe are going to try to install malicious programs on your computer," said Alex Faaborg, a user experience designer in a blog entry last week. "Mozilla is coordinating with Google on this feature."

And in a Bugzilla entry that offers comments from Mozilla and Google employees -- including Chris Hofmann, Mozilla's director of engineering, and Mike Shaver, its director of ecosystem development -- information is even more free-flowing about malicious site blocking in the next major update to Firefox.

The discussion centers on how Firefox 3.0 will warn or alert users to a potentially malicious site. Faaborg mocks up a warning notice, then someone else offers up another option entitled "Scarier error page". But at times the thread lingers on technical issues.

"If a site does not appear in the blacklist but the response from Google says 'this is a malware site,' will Firefox stop showing the page immediately and load this error page in its place?" asked Jesse Ruderman, a PhD student at the University of California, San Diego, and a unpaid Firefox developer.

"I think the plan for malware is to only use the local lists so we don't have to slow down page load or unload a page (which would probably be too late anyway)," replied Tony Chang, one of the Google software engineers who works full-time on Firefox.

"This is an example of how development goes on [at Mozilla]," said Window Snyder, the company's chief security officer. "This is a great example of working with the [open-source] community" in a give-and-take atmosphere where ideas are batted back and forth, she added.

Still, she wouldn't commit Mozilla to adding a malicious blocking tool to the anti-phishing filter already present in Firefox. "It's definitely one of the things we're looking at," Snyder acknowledged, while noting that the feature is currently rated P2 (Priority 2). By Mozilla's definitions, only P1 features are mandatory for Firefox 3.0.

If the security tool makes it into Firefox 3.0's final build, Mozilla will rely on long-time partner Google to provide the blocking blacklists. Google already does that for Firefox 2.0's anti-phishing feature, which is powered by the search giant's open-source "Safe Browsing" code. (Safe Browsing was offered as a separate plug-in for Firefox before Version 2.0, then baked into the Google Toolbar for Firefox.)

But comments made by developers, designers and others on Bugzilla show that Mozilla has questions about the Google technology. "Will the google malware blacklist include sites that are known to be exploiting just Firefox, or IE, or all browsers?" queried Chris Hofmann. "Do we need to make that distinction and/or communicate it to the user so we don't overstep our bounds?"

"What we are actually doing here is giving Google veto power over any web page. Hmm..." added Gervase Markham, a lead developer for Bugzilla.

Google warns its search engine users of potentially dangerous sites with an interstitial page. Google's current blacklists, and presumably those downloaded to Firefox browsers, come from StopBadware.org, a group created by Google, Chinese computer maker Lenovo Group Ltd., and Sun Microsystems Inc. that collects flagged URLs. Some Web sites, however, including one associated with a in Kansas educational service center, have complained that Google erroneously blocks their sites.

No other browser currently includes an integrated tool for blocking sites flagged for downloading malicious code. When asked if Mozilla sees this as a chance to pull away from the competition, Snyder said: "We're always looking for ways to keep our users safe."

Mozilla's developers have until mid-July to add the feature to Firefox 3.0. According to Mozilla's development schedule, the browser will be feature-frozen for Beta 1 on July 17.

That urgency was communicated by at least one Bugzilla commenter. "Alex's design depends on being able to render error messages as he mocked up, which I'd love to see, but am not sure we can do," said Mozilla's Mike Beltzer. "We need to scope and determine that feasibility pretty damned quickly, IMO."