The issue here is that Apple, like most OS vendors, still don't seem to use the IOMMU facilities built into chipsets, especially for untrusted devices, like anything connected to a thunderbolt port. Considering that the Firewire attack has been known for several years, it's rather foolish that a company would implement a spec that can provide direct access to RAM without such basic precautions.
A good account of the current state of affairs is here:
http://derflounder.wordpress.com/2012/02/05/protecting-yours...
And a diagram of protection methods that do work:
http://www.frameloss.org/2011/09/18/firewire-attacks-against...
I had thought that the OS X FW drivers didn't map any RAM until a driver requested some 1394 address space, but apparently that isn't the case... That would be the sane and easy way to fix this.
"We have successfully tested that after unloading AppleFWOHCI.kext the current tools won't work anymore."
If that's true then an option for those who need to use FW/TB devices is to remove the drivers from the system folder to prevent loading at startup and kextload/kextunload on demand.
The following named drivers are present in "/System/Library/Extensions/" :
IOFireWireAVC.kext IOFireWireFamily.kext //(The AppleFWOHCI.kext mentioned above is included here) IOFireWireIP.kext IOFireWireSBP2.kext IOFireWireSerialBusProtocolTransport.kext
IOThunderboltFamily.kext AppleThunderboltDPAdapters.kext AppleThunderboltEDMService.kext AppleThunderboltNHI.kext AppleThunderboltPCIAdapters.kext AppleThunderboltUTDM.kext
Lion even disables Firewire DMA when the screen is locked if you are running Filevault, or if you have an EFI password.
The second thought was, gee, what if someone writes a crappy driver that scribbles another hosts memory.
I am shocked, shocked, good sir!
If this was VGA or DVI, you have no reason to be suspicious. But with Thunderbolt, you can never be sure anymore.
Physical access is relative. 'Remote' vulns are still exploited with some level of physical access: i.e. via a network that lets you touch bits on the other side of the machine's ethernet jack / wireless card.
The other extreme is standing over the ripped carcass of the machine case, triumphantly raising an unencrypted hard disk over your head, and blowing a kiss to the receptionist on your way out through the main lobby.
The OP's attack can be staged multiple hops away, through a physical network of peripheral devices. In a heavy SAN or PPPoFW environment, where FW cables are regularly disappearing under desks, a somewhat-insider could dump a lot of RAM.
RAM which, for some goddamned reason on OS X, apparently contains an unencrypted copy of my login password?! Ouch.
Really? Most software does that, most crypto software and encryption algorithms are vulnerable to RAM attacks. It's not as easy to protect against that as you think it is.
Did I mention that Thunderbolt daisychains, so compromising a Thunderbolt monitor (or better still, projector) is a simple matter of plugging an attack machine into the Daisy-chain out port.
Who really worries about plugging their laptop into a projector?
Added to the bucket list.
