Indeed, it wouldn't surprise me if cryptolocker or it's ilk will look for bitcoin (etc.) private keys while it's doing it's evil stuff from your PC. So physical

Indeed, it wouldn't surprise me if cryptolocker or it's ilk will look for bitcoin (etc.) private keys while it's doing it's evil stuff from your PC. So physical access is not a requirement. To some extent one should assume everything on your PC could be accessed by a criminal (like your house... which is why people buy safes)