In March 2015, Google announced its intention to offer up to $100,000 for an exploit chain that would lead to a persistent compromise of a Chromebox or Chromebook in guest mode via a web page. Prior to that, the company had offered $50,000 for such an exploit.
A researcher who uses the online moniker Gzob Qq informed Google on September 18 that he had identified a series of vulnerabilities that could lead to persistent code execution on Chrome OS, the operating system running on Chromebox and Chromebook devices.
Gzob Qq provided Google a proof-of-concept (PoC) exploit tested with Chrome 60 and Chrome OS platform version 9592.94.0. Google patched the vulnerabilities on October 27 with the release of Chrome OS 62 platform version 9901.54.0/1, which also addressed the recently disclosed KRACK vulnerabilities.
Google informed the researcher on October 11 that he had earned the $100,000 Pwnium reward. Pwnium was a single-day hacking competition that Google held every year alongside the CanSecWest conference until February 2015, when it decided to turn Pwnium into a year-round program.
Gzob Qq’s initial report, which describes the entire exploit chain, was made public by Google earlier this week, along with the advisories for each of the vulnerabilities it leverages.
This is not the first time the researcher has earned a $100,000 reward from Google. Roughly one year prior, he reported a similar Chrome OS exploit chain for which he received the same amount.
Back in 2014, at the Pwnium competition, researcher George Hotz earned $150,000 for a persistent Chrome OS exploit.