[StapleHorse]

Nice. I wonder if something like this has been ever used to exfiltrate data from some air gapped computer.

Some years ago I tried the FM transmitter via GPIO hack for the raspberry pi. The range was surprisingly high, around 100m. First google result. https://linuxhint.com/turn-raspberry-pi-fm-transmitter/

[idiotsecant]

Definitely. All you have to do is look at American military intelligence's insistence on using SCIFs for viewing and working with sensitive electronic (and physical, but for more boring reasons) documentation.

https://en.wikipedia.org/wiki/Sensitive_compartmented_inform...

They know it's important to limit what kind of emissions make it from your equipment to the outside world because they've successfully used exactly these techniques in the past to extract information from others.

[dmajor2]

It very much has been exploited since the beginning of computing https://en.wikipedia.org/wiki/Tempest_(codename)

[carapace]

Yeah. If you've ever wondered why, when you type in a password, it shows up as asterisks or dots, now you know. TEMPEST is why.

[toast0]

Does showing asterisks or dots help mask the signals from the keyboard vs not showing anything (ala most unixy auth)?

I'm pretty sure passwords are not shown to reduce shoulder surfing, especially from across the room.

[jonathankoren]

The dots are just there for shoulder surfing and to give a visual feedback to the user.

If you want to steal a password, all the cool kids use a microphone or your phone's accelerometers.

https://arxiv.org/abs/1609.09359

https://www.cise.ufl.edu/~traynor/papers/marq-ccs11.pdf

https://phys.org/news/2017-04-criminals-pin-tracking-motion....

[carapace]

Those are much more recent attacks. We're talking about a time when CRT screens were the norm, they are noisy enough to read from quite a distance.

> A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen.

https://en.wikipedia.org/wiki/Cathode-ray_tube

That causes a bit more signal than a keyboard, mic, or MEMS accelerometer, eh? :)