I can see some concerns over this, but at the same time hasn't the conventional wisdom always been that you can do anything given physical access to a machine?
The problem with this is that you can be tricked into giving access to it. I would not count plunging a display adapter into my computer giving someone "physical access" but in this case it would do.
Very true. It seems like a simple thing to loudly inform the user that a new PCI device was connected. But that would probably only help savvy people--everyone else would just click ok without reading the dialog.
A real solution would be some sort of DMA whitelist provided by the OS driver.
Physical access should not mean getting close with a wire, it should mean opening the case and messing with the internals.
Your personal preferences are irrelevant to a concept that has been proven over centuries. Physical access is physical access, and I can get root while sitting at most unix-like OSes (including yours) without touching a nutdriver.
I like their scenario of a projector that could dopy the entire contents of a hardrive in the background. But that would require a projector that would do such a thing.
I think what would be an even better scenario is that, since Thunderbolt devices are meant to be daisy-chained and have 2 ports for that purpose, a 'standard' thunderbolt projector could have a homebrew device chained to it, that the presenter knows nothing of. (Hidden, explained as something else, etc). Then this standard-made projector can be made to be a malicious one simply by daisychaining another device on to it that could copy the contents of the presenter's hard drive.
This reminds me of a report we got while building a unix clone. The report stated that a user could craft a setuid root program on a floppy and if any random user executed that file if the floppy was mounted, then the machine was owned.
Wouldn't true security professionals understand that once you grant physical access to the machine, that all is lost?
If I remember correctly you are able to exploit DMA access through firewire by creating an iPod that would be able to dump the contents of memory to the hard drive. If you had DMA access using Thunderbolt you could dump the contents of memory in a very short time!
And even better, you can get access to the other PCIe devices--in particular the SATA devices. Though it might be tough to talk to devices that the main processor is actively using. Even if you somehow disable interrupts on the device, the potential for conflicts (leading to data corruption) seems amazingly high.
It's funny the first thing I thought about when I heard about thunderbolt was "awesome! Now I can build a ghetto NUMA system". But I guess others are concerned about security.
http://www.mactech.com/articles/mactech/Vol.21/21.02/Securit...
(halfway down, "Disabling Fiewire Direct Memory Access", EFI passwords on x86 do the same as OF passwords on PPC machines)