Comment 2 for bug 1393612

Sadly, the solution is not easy nor obvious. Ubuntu is used in a wide variety of different ways and many of them do not lend themselves well to just popping up a dialog box.

Furthermore, the problem is not at all restricted to just devices that can be reprogrammed to act like keyboards.

A fairly lengthy discussion can be found here: http://www.openwall.com/lists/oss-security/2014/08/09/4

Thanks