Bridging the Air Gap: Inaudible Data Exfiltration by Insiders
Samuel Joseph O’Malley, Kim‐Kwang Raymond Choo · Journal of the Association for Information Systems · 2014
As critical systems are increasingly dependent on software and are connected to the Internet, insider threats will be of ongoing concern. For example, corrupt insiders could deliberately introduce malicious software into the organisation’s system to surreptitiously gain control, and launch online attacks via and against compromised systems. In this paper, we present a method that an insider can use to facilitate data exfiltration from an air-gapped system without using any modified hardware. The method presented here uses inaudible sounds transmitted from the target machine’s speakers, which can transfer data to a nearby computer equipped with a microphone. We demonstrate how inaudible communication bridge airgapped systems without any additional hardware. Our system is low-risk for an insider as it only requires one-off access to a system, and can be erased leaving little-to-no trace once it is no longer required. Finally we provide some recommendations for organisations to avoid similar data exfiltration techniques.