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.<p>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?<p>Do other media that most computers accept these days e.g. sd cards support arbitrary code execution too?  How can you get around this?<p>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.