Apparently a lot of people on this website staunchly believe that the Earth's atmosphere is but a warm fuzzy coat protecting us from the frigid winter temperatures of outer space.
I just cannot even anymore.
Your air-gapped servers are covered by a faraday cage, you think you're safe from key exfiltration? You fool.
Low-frequency magnetic fields pass right through Faraday cages.
Researchers were able to extract data off an air-gapped shielded computer by spawning fake work loads