Security expert Charlie Miller of Accuvant says he's discovered that Apple laptops are vulnerable to being hacked through the chip that manages battery charging.
The problem he says, is that the chips are shipped with default passwords - and that hackers who know these passwords can use them to install malware that could steal data, control the computer or brick it completely.
And with Apple batteries no longer removable, there's nothing that can be done to revive the machine.
Miller was able to capture two passwords associated with a 2009 firmware update from Apple - and used them to disable batteries and rewrite the chip's firmware. He bricked seven machines during the tests.
Paul Ducklin of security firm Sophos says that similar techniques could in theory be used to hack any hardware with field-updatable firmware.
"That includes the motherboard itself, your wireless card, your 3G modem, network card, graphics device, storage devices and much more," he says.
But, says Ducklin, reports that Miller's technique could be used to make a battery explode are a little alarmist. The batteries have built-in safeguards against explosions, such as fuses based on an alloy that melts at high temperatures, breaking the circuit.
Miller plans to present his results next month at the Black Hat security conference in Las Vegas. He says he has a fix for the problem, which rewrites a battery's default passwords to a random string of characters.