AirHopper: Bridging the Air-Gap between Isolated Networks and Mobile Phones using Radio Frequencies
This addresses a critical problem for cybersecurity professionals by demonstrating a novel exfiltration method from isolated networks, though it is incremental in building on known radio emission techniques.
The authors tackled the challenge of data exfiltration from air-gapped networks by developing AirHopper, a malware that uses FM signals to transmit data to nearby mobile phones, achieving effective bandwidths of 13-60 Bps over distances of 1-7 meters.
Information is the most critical asset of modern organizations, and accordingly coveted by adversaries. When highly sensitive data is involved, an organization may resort to air-gap isolation, in which there is no networking connection between the inner network and the external world. While infiltrating an air-gapped network has been proven feasible in recent years (e.g., Stuxnet), data exfiltration from an air-gapped network is still considered to be one of the most challenging phases of an advanced cyber-attack. In this paper we present "AirHopper", a bifurcated malware that bridges the air-gap between an isolated network and nearby infected mobile phones using FM signals. While it is known that software can intentionally create radio emissions from a video display unit, this is the first time that mobile phones are considered in an attack model as the intended receivers of maliciously crafted radio signals. We examine the attack model and its limitations, and discuss implementation considerations such as stealth and modulation methods. Finally, we evaluate AirHopper and demonstrate how textual and binary data can be exfiltrated from physically isolated computer to mobile phones at a distance of 1-7 meters, with effective bandwidth of 13-60 Bps (Bytes per second).