content: Since you're specifically saying that it can't execute anything then no, the questions doesn't really make sense. When it reads the file it has to do something with them, usually just putting them in to RAM which doesn't do any operation on the data.  There's a difference between reading and executing. For example in Windows and Linux you can give a user read permissions without giving them read/execute priveleges. Look up the chmod command for linux to see what I'm talking about.  USB drives are basically auto-executing. So the data on them is safe to store or read if you can not  ffa   auto-execute, but your Windows box always auto-executes a small chunk of it to make sure all the proper drivers and backdoors are working. Edit: just realized SD cards were mentioned too. I have no idea how they work since I haven't had to mess with them but I assume they're closer to USB than CD since they would have to set up parameters for talking to the computer before starting data transfer.   Yeah, I was informed earlier they're basically like a USB, they have firmware and micro-controllers as well . Of course the firmware can be overwritten just like on USB. Everybody needs the ability to update their SD Cards and USB flash drives. /s This blog explains the SD Card's operations & vulnerabilities very well  http://www.bunniestudios.com/blog/?p=3554