Whitehats break out of Google Chrome sandbox
ASLR and DEP, too
Researchers say they've developed attack code that pierces key defenses built into Google's Chrome browser, allowing them to reliably execute malware on end user machines.
The attack contains two separate exploits so it can bypass the security counter measures, which include address space layout randomization (or ASLR), data execution prevention (or DEP), and a “sandbox” designed to isolate browser functions from core operating-system operations. So far, there have been relatively few reported exploits that can penetrate the sandbox, and that's one of the reasons the browser has managed to emerge unscathed during the annual Pwn2Own hacker competition for three years in a row.
“While Chrome has one of the most secure sandboxes and has always survived the Pwn2Own contest during the last three years, we have now uncovered a reliable way to execute arbitrary code on any installation of Chrome despite its sandbox, ASLR and DEP,” researchers from France-based Vupen Security wrote in a blog post published on Monday.
They included a video showing the latest version of Chrome running on a 64-bit version of Windows 7. By loading the address of a specially designed website, the researchers are able to force the browser to download and run a calculator application without crashing or showing any other signs of anything amiss.
The Vupen researchers said they plan to share technical details of the exploit only with government customers “for defensive and offensive security.” Neither Google nor the public will be privy to the specifics.
“We're unable to verify VUPEN's claims at this time as we have not received any details from them,” a Google spokesman said. “Should any modifications become necessary, users will be automatically updated to the latest version of Chrome.”
Google to date has awarded more than $150,000 under its bug bounty program, which pays as much as $3133.7 for reports of serious security bugs.
As is typical with attacks that bypass security sandboxes, the Vupen proof-of-concept actually contains two separate exploits, said Chaouki Bekrar, the company's CEO. In an email, he expanded:
The first one results in a memory disclosure and corruption leading to the bypass of ASLR/DEP and execution of the first payload as low integrity level (inside the sandbox). A second payload is then used to exploit another vulnerability which allows the bypass of the sandbox and execution of the final payload with Medium integrity level (outside the sandbox).
Bekrar described one of the exploited flaws as a memory-corruption vulnerability and the other as a design error. ®