AIR-FI: Generating Covert Wi-Fi Signals from Air-Gapped Computers Mordechai Guri Ben-Gurion University of the Negev, Israel Cyber-Security Research Center
[email protected] demo video: https://www.youtube.com/watch?v=vhNnc0ln63c air-gap research page: http://www.covertchannels.com Abstract—In this paper, we show that attackers can exfiltrate deceived insiders [20][5]. These techniques allow the attackers data from air-gapped computers via Wi-Fi signals. Malware in to insert targeted malware into systems within the isolated a compromised air-gapped computer can generate signals in the environment. Wi-Fi frequency bands. The signals are generated through the memory buses - no special hardware is required. Sensitive data One of the most famous incidents in which the air-gap can be modulated and secretly exfiltrated on top of the signals. was breached involved the Stuxnet worm which targeted su- We show that nearby Wi-Fi capable devices (e.g., smartphones, pervisory control and data acquisition (SCADA) systems and laptops, IoT devices) can intercept these signals, decode them, destroyed an estimated 1,000 centrifuges at an Iranian uranium and send them to the attacker over the Internet. To extract enrichment facility [53]. In 2018, the US Department of the signals, we utilize the physical layer information exposed by the Wi-Fi chips. We implement the transmitter and receiver Homeland Security accused Russian hackers of penetrating the and discuss design considerations and implementation details. We internal network of America’s electric utilities [4]. In 2019, the evaluate this covert channel in terms of bandwidth and distance media reported that the Kudankulam Nuclear Power Plant was and present a set of countermeasures.