[walty]

Also interesting that "All the frameworks used USB drives as the physical transmission medium to transfer data in and out of the targeted air-gapped networks. We have not found any case of actual or suspected use of covert physical transmission mediums, such as acoustic or electromagnetic signals."

[jonathankoren]

Probably because to get this stuff to work is really hard in practice.

Several years ago, we were playing with https://github.com/fulldecent/system-bus-radio to work, but we couldn't, even though we had the right MacBooks.

[tbihl]

Alternatively, such a tool would be so valuable that it would be carefully and sparingly employed.

Go too far down that rabbit hole, though, and you start getting into badBIOS territory (a great "conspiracy" theory in the sense of a wild and unprovable idea, though not in the sense of any actual conspiracy.)