Google today said it had paid a researcher $40,000 for a partial exploit of Chrome OS at its Pwnium 3 hacking contest two weeks ago.

The researcher, known as "Pinkie Pie," was the only participant who submitted an exploit during the challenge Google ran March 7 at CanSecWest, the Canadian security conference which also hosted the eighth-annual Pwn2Own contest.

Two others had been working on Chrome OS exploits for Pwnium, said Google, but neither wrapped up in time, even after the contest deadline was extended.

According to Chris Evans, an engineer with the Chrome security team who announced the award on the Chromium blog, Pinkie Pie submitted a "plausible bug chain involving video parsing, a Linux kernel bug and a config file error" in Chrome OS, Google's browser-based operating system.

Pinkie Pie is no stranger to Google's hacking contests.

Last year, he took home $120,000 from the first two Pwniun contests, winning $60,000 in March 2012 after chaining a half-dozen vulnerabilities to bring down Google's Chrome, and another $60,000 in October with an exploit of the browser at the second Pwnium, held in Kuala Lumpur, Malaysia.

Google patched the two vulnerabilities disclosed by Pinkie Pie Friday in an update to Chrome OS. As is Google's practice, it has barred public access to the technical details of those bugs.

Pwnium 3 had attracted attention for its large awards -- up to $150,000 for each hack -- the $3.14 million Google committed to spending if necessary, and the focus on Chrome OS, which powers notebooks such as the $249 Samsung Chromebook and Google's own $1,299 Chromebook Pixel.

It was the first Google-sponsored contest to shift the target from Chrome the browser to Chrome OS.

Google was able to change the focus because the search giant agreed to co-sponsor Pwn2Own, which in turn offered top dollar -- $100,000 -- to the first Chrome hack. A two-man team from MWR InfoSecurity broke into Chrome 25 on Windows 7 by exploiting a pair of "zero-day," or unpatched, vulnerabilities in the browser and operating system.

The MWR team included Nils -- a young German who is known only by his first name -- and Jon Butler. Nils has his own Pwn2Own history: He won $10,000 by hacking Mozilla's Firefox in 2010, and $15,000 the year before for exploiting Firefox, Internet Explorer 8 (IE8) and Apple's Safari.

Google patched the Nils/Butler Chrome bug last Thursday, about 24 hours after the company's security team received the vulnerability information and a working exploit. The Windows kernel flaw they also used in their attack was passed along to Microsoft for analysis and patching.

Pinkie Pie, whose prior hacking has been called "works of art" by Google engineers, got another shout-out from the company today.

"We'd like to thank Pinkie Pie for honoring the spirit of the competition by disclosing a partial exploit at the deadline, rather than holding on to bugs in lieu of an end-to-end exploit," said Google's Evans. "This means that we can find fixes sooner, target new hardening measures and keep users safe."

Google also runs bug bounty programs for Chrome and its Web properties, including youtube.com and google.com. Bounties for both programs were boosted last summer, with payments increased to as much as $20,000 for remote code vulnerabilities in its core domains.

Today, Google said that the total pay-out from its contests and Chrome bounty program has exceeded $900,000. When bounties for Web properties vulnerabilities are included, it's awarded more than $1.5 million to date.

HP TippingPoint, which co-sponsored Pwn2Own with Google this year, awarded several other prizes to researchers, including $250,000 to Vupen, a French vulnerability research and bug-selling firm, for hacking IE10, Firefox, and Adobe's Flash Player and Reader plug-ins.

Altogether, Pwn2Own issued checks totaling $480,000 to participating researchers.

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

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