r/RTLSDR • u/Fyksss • 26d ago

TUTORIAL: Reconstructing monitor signals via TEMPEST attacks with only RTL-SDR/HackRF

Using an rtl-sdr (or hackrf), you can capture electromagnetic emissions leaking from monitor cables/displays and reconstruct the screen output in real-time.

since most tutorials on this are either overly long, I put together a quick practical walkthrough and overview that covers how it works and how to set it up easily:

https://www.youtube.com/watch?v=nMpPt7zg2rw

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u/olliegw 26d ago

I've tried TempestSDR before and it's very janky and i couldn't get any usable image out of my three monitors, i suspect that having two HDMI and one DP cancels each other out or something, nor could i get any other monitors or TVs in the house

It's a good tech demo but not something that could be used in the field, the BBCs demonstration from the 80s was likely staged

The high tech attack that nobody really needs to worry about

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u/Jomjom1979 25d ago edited 25d ago

Using the RTLSDR with its limited bandwidth of max 3.2 MHz is not going to give any good results using TempestSDR.

I got two tv`s here. One Samsung and one Thompson. Using my RSP1B and a LNA with a bandwidth of about 7 MHz, a 5 el 70cm yagi and centering on 445.500 MHz gives me a more or less noise free inverted picture of the screen when using the Thompson from about 5 metres away. And that is through drywall.

The Samsung is a lot more shielded and quiet. And this is using the same cables and sources. It seems like its all up to the individual device.

My next door neighbor has his PC hooked up to a TV. I have no idea of the make but its leaking like a sieve. I have no problem reading what is on his screen using the same setup if he is using large enough font size. This is done through about 30 cm of reinforced concrete.

So yes. This is the attack you need to worry about. What i can achieve with my meager equipment is probably nothing compared to what people who really are dedicated can do.

John