Bad news for security enthusiasts with air-gapped systems, This technique is based on the idea that two computers will be isolated from each other if there is no physical or logical connection linking them, Researchers have explained how this system could become insecure simply by turning speakers into ultrasonic transmitters.
Since computers come with interfaces not designed for communication, It is necessary to covertly modify one of them to bridge this gap. According to research from Israel's Ben-Gurion University of the Negev, This affects devices such as speakers and headphones.
The same research center has claimed to be able to use speakers and headphones to act as microphones and receive data. The devices can be used to send the signals back and make the supposedly safe practice of Air-Gapped systems less secure.
However, doing the same for two devices of the same type (speakers and headphones designed to transmit sound) it should be much more difficult.
Overcoming this required the exploitation of two obscure techniques: The reversibility of the speaker and jack reassignment. Reversibility is based on the observation that speakers and headphones can be considered microphones in reverse: A speaker converts electrical signals into a sound waveform, mientras que un micrófono transforma los sonidos en señales eléctricas.
Los investigadores descubrieron que es posible utilizar la inversión eléctrica para convertir un altavoz o auriculares en un dispositivo que se comporte como un micrófono tosco.
Los autores también proporcionaron varias técnicas de mitigación pero admitieron que todas tenían sus limitaciones. Estas técnicas incluyeron el diseño de altavoces y auriculares equipados con amplificadores integrados para evitar su uso como micrófono.