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Private Data Exfiltration From Cyber−Physical Systems Using Channel State Information

Thomas Burton and Kasper Rasmussen

Abstract

Data exfiltration methods aim to extract data without authorization from a network or device without detection. In this paper, we present a novel data exfiltration method using Channel State Information (CSI) from ambient WiFi signals. Modulation is performed by modifying the environment by moving a physically actuated machine resulting in a change to the channel response that is measurable by a distant receiver capable of collecting CSI samples. An attacker can use this to exfiltrate data when transmission using conventional methods is impossible, yet the attacker controls a moving mechanism. We discuss the design of the covert channel in detail and produce a proof of concept implementation to evaluate the performance in terms of communication quality. We find that even a simple implementation provides robust communication in an office environment. Additionally, we present several countermeasures against an attack of this type.

Book Title
Workshop on Privacy in the Electronic Society
Month
November
Year
2021