Yesterday, I wrote about all the great things Apple did to improve security in its new operating system. Today however, we got a new, and quite different, vulnerability. It turns out that the firmware in Apple's laptop batteries is secured with a default passwords. An attacker would be able to use this password to change the battery firmware or settings, permanently ruining the battery. So its more of a denial of service attack. Persistent malware should be possible but it is not clear how much access it would have to the system.

It is always amazing what devices have firmware which may be manipulated by an attacker. I remember a while back a firmware update for the display port to VGA addapter. If there is a firmware update, there is always a change for a malicious firmware install. Recently, we talked about thunderbolt, Intel's new interface standard that provides direct bus access similar to Firewire. Thunderbolt cables are fare removed from "pairs of copper" we are used to. Instead, each thunderbolt cable has active circuits, and you guessed it, firmware embedded in the connector.

A malicious thunderbolt cable could potentially have direct access to system memory and disk.

http://blogs.forbes.com/andygreenberg/2011/07/22/apple-laptops-vulnerable-to-hack-that-kills-or-corrupts-batteries/

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Johannes B. Ullrich, Ph.D.
SANS Technology Institute
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