Air-gap researcher Mordechai Guri created the proof-of-concept (PoC) attack and described it in a research paper released earlier this month. At a top speed of 100 bps, it would take 22 hours and 13 minutes to send 1MB of data to a receiving device no more than 69 inches away. Guri explains planting malware could be done by a nation-state adversary at the time of manufacturing, during the shipping of equipment or simply via an infected USB drive plugged into the targeted computer.
Source: https://threatpost.com/air-gap-attack-turns-memory-wifi/162358/