Friday, July 22, 2011

Apple Laptops Vulnerable To Hack That Kills Or Corrupts Batteries

Via (Firewall Blog) -

Your laptop’s battery is smarter than it looks. And if a hacker like security researcher Charlie Miller gets his digital hands on it, it could become more evil than it appears, too.

At the Black Hat security conference in August, Miller plans to expose and provide a fix for a new breed of attack on Apple laptops that takes advantage of a little-studied weak point in their security: the chips that control their batteries.

Modern laptop batteries contain a microcontroller that monitors the power level of the unit, allowing the operating system and the charger to check on the battery’s charge and respond accordingly. That embedded chip means the lithium ion batteries can know when to stop charging even when the computer is powered off, and can regulate their own heat for safety purposes.

When Miller examined those batteries in several Macbooks, Macbook Pros and Macbook Airs, however, he found a disturbing vulnerability. The batteries’ chips are shipped with default passwords, such that anyone who discovers that password and learns to control the chips’ firmware can potentially hijack them to do anything the hacker wants. That includes permanently ruining batteries at will, and may enable nastier tricks like implanting them with hidden malware that infects the computer no matter how many times software is reinstalled or even potentially causing the batteries to heat up, catch fire or explode. “These batteries just aren’t designed with the idea that people will mess with them,” Miller says. “What I’m showing is that it’s possible to use them to do something really bad.”


Miller says he’s received messages from several other researchers asking him not proceed with the battery work because it could be too dangerous. But Miller has worked to fix the problems he’s exposing. At Black Hat he plans to release a tool for Apple users called “Caulkgun” that changes their battery firmware’s passwords to a random string, preventing the default password attack he used. Miller also sent Apple and Texas Instruments his research to make them aware of the vulnerability. I contacted Apple for comment but haven’t yet heard back from the company.

Implementing Miller’s “Caulkgun” prevents any other hacker from using the vulnerabilities he’s found. But it would also prevent Apple from using the battery’s default passwords to implement their own upgrades and fixes. Those who fear the possibilities of a hijacked chunk of charged chemicals in their laps might want to consider the tradeoff.

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