Google engineers deny Chrome hack exploited browser's code

Vupen used a bug in bundled Flash, say Google devs; "Not a Chrome pwn"

Several Google security engineers have countered claims that a French security company found a vulnerability in Chrome that could let attackers hijack Windows PCs running the company's browser.

Instead, those engineers said the bug Vupen exploited to hack Chrome was in Adobe's Flash, which Google has bundled with the browser for over a year.

Google's official position, however, has not changed since Monday, when Vupen announced it had successfully hacked Chrome by sidestepping not only the browser's built-in "sandbox" but also by evading Windows 7's integrated anti-exploit technologies.

"The investigation is ongoing because Vupen is not sharing any details with us," a Google spokesman said today via email.

But others who work for Google were certain that at least one of the flaws Vupen exploited was in Flash's code, not Chrome's.

"As usual, security journalists don't bother to fact check," said Tavis Ormandy, a Google security engineer, in a tweet earlier today. "Vupen misunderstood how sandboxing worked in Chrome, and only had a Flash bug."

"It's a legit pwn, but if it requires Flash, it's not a Chrome pwn," tweeted Chris Evans, a Google security engineer and Chrome team lead, using the security-speak term for compromising an application or computer.

Justin Schuh, whose LinkedIn account also identifies him as a Google security engineer, chimed in with, "No one is saying it's not a legit exploit. The point is that it's not the exploit [Vupen] claimed."

When asked to confirm the source of the vulnerabilities it exploited, Vupen was blunt in its refusal to share any information.

"We will not help Google in finding the vulnerabilities," said Chaouki Bekrar, Vupen's CEO and head of research, in an email reply to questions. "Nobody knows how we bypassed Google Chrome's sandbox except us and our customers, and any claim is a pure speculation."

Last year, Vupen changed its vulnerability disclosure policies when it announced it would no longer report bugs to vendors -- as do many researchers -- but instead would reveal its work only to paying customers.

Today's Twitter back-and-forth between Google's engineers and Bekrar grew heated at times.

"When it comes to critical vulnerabilities, all software vendors/devs (including Google) always try to downplay the findings," Bekrar said on Twitter.

"I was thinking something similar about researchers who inflate their accomplishments," Schuh replied, also on Twitter, to Bekrar.

The point made by Ormandy, Evans and Schuh was that Vupen didn't exploit a bug in Chrome's own code, but in Flash, which has been partially sandboxed in the stable version of the browser since early March 2011.

While the Google engineers seemed to acknowledge that a bug in Flash was involved in Vupen's exploit, they also defended the sandbox technology -- meant to isolate Flash from the rest of the computer -- even as it apparently failed to prevent an attack.

"The Flash sandbox blog post went to pains to call it an initial step," said Evans. "It protects some stuff, more to come. Flash sandbox [does not equal] Chrome sandbox."

The blog Evans referred to was published in December 2010, where Schuh and another Google developer, Carlos Pizano said, "While we've laid a tremendous amount of groundwork in this initial sandbox, there's still more work to be done."

Chrome's Flash sandbox is currently available only in the Windows version of the browser; Google has promised to implement it in the Mac and Linux editions, but has not yet done so.

While Bekrar later hinted that Vupen's exploit did leverage a Flash vulnerability, he said the attack code also took advantage of at least one other bug. "[Chrome's] built-in plug-ins such as Flash are launched inside the sandbox which was created by Google, so finding and exploiting a Flash or a WebKit vulnerability will fall inside the sandboxes and will not circumvent it," he wrote. "A sandbox bypass exploit is still required."

Chrome has a reputation as a secure browser, in large part because of its sandbox technology. Chrome is the only browser to have escaped unscathed at the last three Pwn2Own hacking contests, the annual challenge hosted by the CanSecWest conference in Vancouver, British Columbia, and sponsored by HP TippingPoint's bug bounty program.

In March 2011, no one took on Chrome at Pwn2Own, even though Google had offered a $20,000 prize to the first researcher who hacked the browser and its sandbox.

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 e-mail address is

Read more about security in Computerworld's Security Topic Center.

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags securitybrowsersGooglesoftwareapplicationsMalware and Vulnerabilities

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Gregg Keizer

Computerworld (US)
Show Comments

Brand Post

Most Popular Reviews

Latest Articles


PCW Evaluation Team

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.

Walid Mikhael

Brother QL-820NWB Professional Label Printer

It’s easy to set up, it’s compact and quiet when printing and to top if off, the print quality is excellent. This is hands down the best printer I’ve used for printing labels.

Ben Ramsden

Sharp PN-40TC1 Huddle Board

Brainstorming, innovation, problem solving, and negotiation have all become much more productive and valuable if people can easily collaborate in real time with minimal friction.

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Featured Content

Product Launch Showcase

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?