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 CSO newsletter!

Error: Please check your email address.

Tags applicationsGooglesecuritybrowserssoftwareMalware and Vulnerabilities

More about Adobe SystemsAppleGoogleHewlett-Packard AustraliaHPLinuxMicrosoftTippingPointTippingPointTopicWest

Show Comments

Featured Whitepapers

Editor's Recommendations

Solution Centres

Stories by Gregg Keizer

Latest Videos

  • 150x50

    CSO Webinar: The Human Factor - Your people are your biggest security weakness

    ​Speakers: David Lacey, Researcher and former CISO Royal Mail David Turner - Global Risk Management Expert Mark Guntrip - Group Manager, Email Protection, Proofpoint

    Play Video

  • 150x50

    CSO Webinar: Current ransomware defences are failing – but machine learning can drive a more proactive solution

    Speakers • Ty Miller, Director, Threat Intelligence • Mark Gregory, Leader, Network Engineering Research Group, RMIT • Jeff Lanza, Retired FBI Agent (USA) • Andy Solterbeck, VP Asia Pacific, Cylance • David Braue, CSO MC/Moderator What to expect: ​Hear from industry experts on the local and global ransomware threat landscape. Explore a new approach to dealing with ransomware using machine-learning techniques and by thinking about the problem in a fundamentally different way. Apply techniques for gathering insight into ransomware behaviour and find out what elements must go into a truly effective ransomware defence. Get a first-hand look at how ransomware actually works in practice, and how machine-learning techniques can pick up on its activities long before your employees do.

    Play Video

  • 150x50

    CSO Webinar: Get real about metadata to avoid a false sense of security

    Speakers: • Anthony Caruana – CSO MC and moderator • Ian Farquhar, Worldwide Virtual Security Team Lead, Gigamon • John Lindsay, Former CTO, iiNet • Skeeve Stevens, Futurist, Future Sumo • David Vaile - Vice chair of APF, Co-Convenor of the Cyberspace Law And Policy Community, UNSW Law Faculty This webinar covers: - A 101 on metadata - what it is and how to use it - Insight into a typical attack, what happens and what we would find when looking into the metadata - How to collect metadata, use this to detect attacks and get greater insight into how you can use this to protect your organisation - Learn how much raw data and metadata to retain and how long for - Get a reality check on how you're using your metadata and if this is enough to secure your organisation

    Play Video

  • 150x50

    CSO Webinar: How banking trojans work and how you can stop them

    CSO Webinar: How banking trojans work and how you can stop them Featuring: • John Baird, Director of Global Technology Production, Deutsche Bank • Samantha Macleod, GM Cyber Security, ME Bank • Sherrod DeGrippo, Director of Emerging Threats, Proofpoint (USA)

    Play Video

  • 150x50

    IDG Live Webinar:The right collaboration strategy will help your business take flight

    Speakers - Mike Harris, Engineering Services Manager, Jetstar - Christopher Johnson, IT Director APAC, 20th Century Fox - Brent Maxwell, Director of Information Systems, THE ICONIC - IDG MC/Moderator Anthony Caruana

    Play Video

More videos

Blog Posts