[topspin]

You've got the basics right. An optimally coupled pair won't radiate. Nothing is optimal, however, so there is a small amount of RF radiation. Obviously this means not all RF energy from the environment is common mode as well. Thus the ever more substantial shielding that has appeared in later copper Ethernet cabling.

The implication of this click bait is that ordinary traffic is being recovered from RF leakage. While that's theoretically possible given short range and a sensitive receiver, what we have here is someone creating a low frequency transmitter using copper Ethernet. That doesn't mean it is without interest or value; dismissing side channels like that has a poor track record. But it's not what you're led to believe with "attack reveals Ethernet cable traffic!"

[marcan_42]

I do wonder how close you'd have to go to actually demodulate real Gigabit Ethernet over the air. Given the 8 simultaneous data streams (4 pairs times two directions), I imagine you'd need at least 8 antennas to get anywhere, probably arranged in very close proximity to the cable to pick up on the spatial differences between the pairs. Then you'd have to use MIMO demodulation techniques. At that point you might as well just tap the cable.

100BASE-TX would be a lot easier, since that just uses a single pair in each direction.

FWIW, this isn't a side channel, at least not the way he's presenting it. It's a covert channel. That's different; side channels leak (significant) information from uncooperating sources. Covert channels require a cooperating source. There's a huge difference. Covert channels are largely academic and almost never relevant in real life. This isn't like research on things like extracting RSA keys from CPU EMI emitted during OpenSSL operations, which is a real side channel and much more valuable research.

[callesgg]

You would probably need to pierce the cable with needles.

[genewitch]

or just tap the fiber optic cables, which seems easier and more reliable than trying to capture stuff with antennas.

[justshowpost]

Tomorrow news: Mordechai Guri uses $50 camera to see thru your optical patchcords!