I saw a tip on our local cyber security center informational page that holding the shift key on Windows while inserting a USB drive protect the system from being filled or attacked by malwares on that USB device.

Is this true? What is the mechanism behind this method? And is it just for the Windows operation system or is it a general rule for all operation systems?

  • holding down shift disables autoplay for removable devices
    – user13267
    Nov 18, 2016 at 5:17

1 Answer 1


In addition to what @matthew has said, there are devices that pretend to be keyboards (most popular one is called a rubber ducky) and will auto type commands at a speed that you either wont see them be executed or if you do, you will be too slow to do anything about it. If you are pressing Shift, Ctrl or Alt then the commands will be changed due to your key press and will fail. Shift is the key that gives you the least amount of protection for this type of attack due to the attach having to be case sensitive to be stopped with it. With Ctrl and Alt a key press will do a completely different operation.

Shift+c produces C

Ctrl+c produces the command "copy"

  • Is there any option in windows to permanently disable autorun of USB?
    – defalt
    Oct 19, 2016 at 10:45
  • 1
    @user334283 in windows 10 you can do it in setting->devices->Autoplay and turn off autoplay for all devices
    – dev-masih
    Oct 19, 2016 at 10:49
  • it is different for all versions of windows, just search for "disable autorun windows X" and replace X with the version of windows you are running. This will not protect you against attacks from rubber duckies Oct 19, 2016 at 10:53
  • When having two keyboards connected, does holding shift on one change the input from the other? (I have no idea, that's why I am asking.)
    – Anders
    Oct 19, 2016 at 11:33
  • 2
    Yes it will, the keyboard sends signals saying that key 21 is pressed or key 33 and 52 are pressed and the computer will interpret that as the symbol it thinks it should be. From my understanding of things is that each key press is put into a buffer without a keyboard identification, This can be seen by the fact that people that want more keys than on a keyboard, they need special software to be able to plug in another keyboard and it act differently to the other one. Oct 19, 2016 at 13:14

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