> I'm not too worried about backdoors in microcontrollers, they're too small to hide much. You can hide a LOT on a chip, though for embedded systems the attack

> I'm not too worried about backdoors in microcontrollers, they're too small to hide much. You can hide a LOT on a chip, though for embedded systems the attacks are not likely to be generic, or scale. If I was a spook agency, I'd definitely try to compromise USB handling, at a low level. Most controllers I know of use DMA, so it's likely that sneaking in a few hundred gates would open up a whole SOC. The USB controllers are just libraries that people buy; I don't know how closely they are audited by customers. Hook that up to a compromised PC (read about system management CPUs...) and that's the ball game. Silicon is pretty opaque.