Since removable media have become very popular now obscure developers, as I call them, have taken on the task of creating viruses to infect these and among them is the one you mention, which can be removed without antivirus with the command (- attrib -s -r -h /s /d). I recommend you another antivirus called Usb Fix that has as a plus the fact that it also disinfects the hard disk of the computer of a possible latent agent that is found. Very good your step by step explanation.