Google, Adobe sandbox Flash for Chrome to protect users

Chrome's 'dev' build for Windows now blocks Flash attack code from infecting PCs

Adobe and Google have collaborated to put the Flash Player plug-in inside a sandbox within Chrome, an effort by the two companies to better protect users from attacks.

The sandbox has been introduced into the roughest version of Chrome -- the "dev" build -- and is currently available only on the Windows edition of Google's browser.

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A "sandbox" isolates processes on the computer, preventing or at least hindering malware from escaping an application to wreak havoc on the machine.

Flash has become a very popular target for hackers, who have regularly exploited its vulnerabilities this year. Adobe has had to patch Flash five times since January, and in several cases had to issue emergency fixes to stymie ongoing attacks.

Apple, which has been squabbling with Adobe over Flash since the 2007 introduction of the iPhone, recently yanked the software from its newest MacBook Air, and plans to eliminate it from future machines as well. It cited security as the reason for dropping Flash from its Mac OS X operating system.

Google took a different tack: It worked with Adobe to craft a sandbox that shelters Flash Player.

"There was a lot of work on both sides," said Peleus Uhley, Adobe's platform security strategist, in a Wednesday interview. "The interfaces to open-source browsers are completely different from, say, Internet Explorer, and we had to restructure Flash Player to put it in a sandbox."

The Flash sandbox uses some elements of the already-in-place technology that Chrome uses to protect HTML and JavaScript, but much of the new work was created from scratch, added Brad Arkin, Adobe's director of security and privacy. "The biggest challenge was getting the full functionally of Flash from within this new sandbox," he said.

Adobe worked with Google to create new APIs (application programming interfaces) to support Flash in a sandbox, a necessary step because Flash Player, unlike HTML and JavaScript, is a plug-in.

"The Flash Player sandbox is specifically designed around Flash's processes and functionality to protect certain sensitive resources from being accessed by malicious code, while allowing the use of less sensitive ones," said Google's Chrome team in an e-mail reply to Computerworld's questions Wednesday.

Specifically, Google's and Adobe's engineers partnered to build a "broker" process, which decides which functions Flash can conduct outside the sandbox, and mediates requests between the plug-in and the rest of the browser, as well as the operating system.

"This restricts the ability of malicious code that may be running in Flash Player to compromise sensitive system resources," Google explained.

"The concept is the same as the sandbox in Reader X," said Uhley, talking about the latest version of Adobe's PDF viewer. "The goal is the same and the model is identical: Flash Player runs with low privileges and uses a broker process. But the sandbox [in Chrome] is very different from the one in Reader X."

While only Windows XP, Vista and Windows 7 versions of Chrome include the new Flash sandbox, Adobe and Google plan to add the security feature to Mac OS X and Linux editions. The companies did not set a timetable for the expansion to those two platforms, however.

"We think of this as a working prototype," said Arkin. "It will progress to maturity with Chrome."

"There are still bugs we're working through, so it will be in the dev channel for a while yet," added Uhley.

Google said the Flash sandbox should show up in the "stable" build of Chrome -- the production version of the browser -- in early-to-mid 2011.

While Adobe said that the quality of this first sandbox is credible, it plans to continue working on the technology until it's rock solid. Arkin compared the Flash sandbox now in Chrome to the quality of the code in Reader X when Adobe issued several private betas to testers before launching the PDF program to the public last month.

"We're confident that when it makes it into the [Chrome] stable channel, it will be solid," said Arkin.

Adobe wants to apply what it learns with Google and Chrome to other browsers, particularly Mozilla's Firefox and Apple's Safari.

"We wanted to do a working prototype [of the sandbox] to make sure we could do it," said Uhley. "But we want to have these same discussions with Mozilla and Apple and see if this will work for them."

Uhley said Adobe couldn't craft a Flash Player sandbox for other browsers without their help. "We can't to it all ourselves," he said. "It requires changes on the browser side as well as in Flash."

Some of the work, including the critical broker process, will be available as open-source in the Chromium project, which feeds into Chrome, said Uhley.

On Google's part, it's planning to add APIs to Chrome that will allow other plug-in makers to run inside a sandbox. "We are always interested in improving plug-in security, and thus we are committed to our ongoing next-generation plugin API work, which provides a standard way for plug-ins to run inside the sandbox," Google said.

Google and Adobe have collaborated on Flash before. Last April Chrome began packaging Flash Player with the browser, which automatically updates Adobe's software when the latter issues security updates.

The Windows Chrome dev build with the Flash sandbox was released yesterday. Users can switch to the dev channel by visiting Chrome's website.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer or subscribe to Gregg's RSS feed. His email address is

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This story, "Google, Adobe sandbox Flash for Chrome to protect users" was originally published by Computerworld.

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