USB Condoms
Recently, it comes to light that those handling the Snowden files are using air-gapped computers and passing encrypted data to the outside world via ... USB sticks.Can't USB sticks execute arbitrary code?  Couldn't an attacker infiltrate the publically accessible computers that these people use and put a data-stealing trojan onto USB sticks used to bridge the air-gap?Do other media that most computers accept these days e.g. sd cards support arbitrary code execution too?  How can you get around this?EDIT: it was DMA attacks that I was thinking off, and USB seems free of them at least.  I guess, if you trust the robustness of your USB stack against exploit, that USB is a fairly safe bet.  As these very people are reading the NSA secrets, one wonders what'd happen if they discovered some hint that that NSA could do precisely that - exploit via USB plugging in.