[muthdra]

A secretly-IoT keyboard that shares your key presses and may "type" malicious stuff when you're not looking at it; the OS wouldn't be able to tell it's not you doing the typing. Not scary at all, no sir.

[yipbub]

It can't read your keypresses (I think)

[int_19h]

So long as it can simulate them, installing a keylogger that can read them too is a matter of a few seconds (to "type" a PowerShell script that will download and execute the desired payload).

[blattimwind]

It can't (unless it's the keyboard cable).

[ngcc_hk]

Hid usually ok with systems and hence a wireless mouse and keyboard pretended.

A windows hack may be - The “mouse” would ask to move to leftmost bottom corner then click. Type searching terms like Cmd<r>. Then if can get hold of the windows one is in ...

Any better idea?

[tyingq]

<windows-key>R brings up a run dialog with the focus already in the text box waiting for a command. No mouse needed.

[muthdra]

Keyboard shortcuts.

[blotter_paper]

I took GP to be speculating about a hypothetical secretly-IoT-keyboard, not the cable being discussed. Similar thoughts are explored in the comments on TFA.

[muthdra]

Yes. I assumed it would be straightforward after you figure out how to hide wifi inside a USB cable.