I have recently read of a dangerous USB drive containing a circuit instead of storage, that destroys the hardware of a computer by injecting a high voltage, high current pulse into the port it is plugged into. See [this article](http://hackaday.com/2015/03/11/killer-usb-drive-is-designed-to-fry-laptops/)

It should be easy to test an unknown USB drive for this sort of danger by plugging it into a separate test module before taking the risk of inserting it into a computer's USB port. Does such a test module exist? Is there a commercial version, a circuit or kit that can be obtained?

Having read that article I would routinely test every USB device before using it.