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Comment by pixelcloud | Hacker News Reader

I would say no.

http://en.wikipedia.org/wiki/DMA_attack

Some servers used to have a resettable "case has been opened" flag in the BIOS - the pieces that was based on could be leveraged against the DMA attacks. Overwrite certain items in memory, or maybe just power off the system, when the box is opened, and obstruct opening of the box (a lot of glue? or somesuch) to extend the time past the "recover memory" window.

Yes, I realize this would still be susceptible to coercion of the humans involved, and other issues, but it could be a building block of some degree of NSA-proofing.

I see this option in my bios switched every time I open my computer. I never thought it might be a security feature, just an flag that must be set for someone with mild OCD.

I'm still not sure how my motherboard detects if my case is open...

Are there any instances of this being used in the field?

Yes, very easy. In a mac you just plug in a Firewire/thunderbolt device[1]. More extreme measures involve freezing the RAM. Both require physical access to the machine, but a bit more scary that plugging your laptop into a public display/TV gives an attacker control of your computer and passwords.

Full disk encryption TrueCrypt/BitLocker/FileVault can act as countermeasures[2] and modern versions of OSX don't allow DMA from the login screen anymore.

[1] http://www.breaknenter.org/2012/02/adventures-with-daisy-in-...

[2] http://www.researchgate.net/publication/49277520_Cold_Boot_M...

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