[throwaway202302]

I’ve read some related things, which said its the hdmi cable that radiates, but I understand any component might be.

Two questions: - How many meters do we need to expect our lcd/ips monitors to radiate? - Do we know about any monitor/cables that prevent the worst radiation and what to buy?

p.s. There are also papers that describe how to pickup keyboard strokes using the same method.

[cushychicken]

Test grade shielded HDMI connectors would probably mitigate this. They’re generally about $50 for 2 meters.

I’d also expect this attack to only work within a few feet of the target system. The author admits that the quality of transmission is pretty heavily affected by antenna and cable orientation. The bigger concern IMO is proximity - if you’re close enough to pull this off, you’re already at “physical access” levels of threat to a secure system.

[throwaway202302]

https://www.lightbluetouchpaper.org/2006/03/09/video-eavesdr...

Rather old one, where 25m was claimed. (Markus Kuhn).

Some like 200m were claimed by anons in random threads (https://www.mikrocontroller.net/topic/319197, in german), but that might have been related to CRT, not sure. They said they pointed antennas towards an office building.

All in all, the topic seems valid but unfortunately the discussions tend to be trolled.

One takeaway from the original link for me was to prefer displayport cable over hdmi/dvi. Yet, if the shielded connectors you have been referring to are easy to find, sounds good as well.

Absolute security is not possible, they say. Yet I wonder, can we have some sort of it at least outside a horizon of lets say 5 meters? Broadcasting the signals few meters/across the street/100m seem to be quite of a difference.

[throwaway202302]

What about the neighbor above/below your apartment? A ceiling of ferroconcrete is a good blocker (or a good multiplier?)

From my apartment, I can see a telecommunication tower, about 1.2 kilometers away. Wondering what it could pick up with enterprise grade antennas if it wanted to. maybe the other monitors around would disturb the signals?

https://www.usenix.org/legacy/events/sec09/tech/full_papers/...

[cushychicken]

A telecom tower has orders of magnitude more transmit power than an HDMI cable, by design. It’s also an intentional, rather than unintentional radiator. However, neither of these facts can overcome the fact that radio energy decays with the inverse square of distance, and that the noise local to the receiver on the telecom tower would swamp any fragment of energy radiated by the hdmi cable by the time it got there.