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Microsoft patches 'sexy' Bluetooth bug in Vista, Windows 7

Difficult to pull off, say experts, but worthwhile for high-value targets

July 12, 2011 03:59 PM ET

Computerworld - Microsoft today patched 22 vulnerabilities in Windows and Office, including a bug in the Bluetooth technology within Vista and Windows 7 that could be used to hijack a nearby PC.

Of Tuesday's four updates, called "bulletins" by Microsoft, only one was labeled "critical" -- the most-serious rating in the company's four-step scoring system -- while the other three were marked "important," the next-most-dangerous category.

The 22 individual bugs patched today were more than in most odd-numbered months, which are typically light months for Microsoft. July's total was bested only by April's 64 and June's 34, and was tied with February's.

The standout bulletin was clearly the sole critical update, MS11-053, researchers said today.

"It's quirky, and it's remotely exploitable," said Andrew Storms, director of security operations for nCircle Security, of the Vista and Windows update that plugs a hole in the operating systems' Bluetooth stack.

"It's at the top of our priority list," echoed Amol Sarwate, manager of Qualys' vulnerability research lab. "It could be exploited against someone using a Bluetooth mouse or headset, perhaps in a coffee shop, so it's tremendously important that people apply the patch, or if they can't do that, disable Bluetooth [on Vista and Windows 7]."

"This one's sexy," said Marcus Carey, a security researcher with Rapid7. "It's classical spy kind of stuff, being able to access [a PC] using Bluetooth when [the victim] doesn't even know you're there. All [an attacker] would have to do is go to Washington, D.C. or northern Virginia, where lots of U.S. government employees work, and sit at a Starbucks or somewhere else with free Wi-Fi."

Windows XP is not affected by the vulnerability. Although the 10-year-old operating system supports Bluetooth, Microsoft rewrote its supporting code for Vista.

Microsoft also had MS11-053 at the top of its patch chart today, but cited several caveats to explain why it believes attackers will not be able to come up with a reliable exploit in the next month.

"Your system's 48-bit Bluetooth address is not 'discoverable' by default," said Jonathan Ness, an engineer with the Microsoft Security Response Center, in a blog post today. "In the default state, an attacker must obtain your Bluetooth address another way -- either via brute forcing it or extracting it from Bluetooth traffic captured over-the-air."

The former could take an attacker hours, Ness added, while the latter requires specialized hardware that costs thousands.

Even so, experts pointed out that the Bluetooth vulnerability might be worthwhile to some attackers.

"I can see this being used in really, really targeted attacks," said Sarwate. "If someone knows you are a CEO, and may even be following you, they could exploit this to try to gain access to your system."

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