Airgapped systems have an air gap between the system and the wider world. The only way to move data to and from them is for someone to walk across the gap with physical media.
There are no communication cables between the host system and the wider world.
* air-gap malware can be designed to communicate secure information acoustically, at frequencies near or beyond the limit of human hearing.
* In 2014, researchers introduced ″AirHopper″, a bifurcated attack pattern showing the feasibility of data exfiltration from an isolated computer to a nearby mobile phone, using FM frequency signals.
* In 2015, "HELLONE", a covert signaling channel between air-gapped computers using thermal manipulations, was introduced. "BitWhisper" supports bidirectional communication and requires no additional dedicated peripheral hardware.
* Later in 2015, researchers introduced "GSMem", a method for exfiltrating data from air-gapped computers over cellular frequencies. The transmission - generated by a standard internal bus - renders the computer into a small cellular transmitter antenna.
There are no communication cables between the host system and the wider world.