SmartAttack: Air-Gap Attack via Smartwatches

2025-06-10

AI Summary

Prior work has not systematically evaluated the eavesdropping potential of smartwatches as ultrasonic receivers in air-gapped scenarios. Method: This paper introduces the first covert air-channel communication scheme operating at 18–22 kHz, leveraging built-in smartwatch microphones for cross-domain data exfiltration. It innovatively models human-body channel attenuation, microphone directivity, and ambient noise, and designs a lightweight modulation/demodulation scheme with robust signal acquisition. Contribution/Results: Experiments demonstrate a bit error rate below 2.3% at 3-meter distance, across multiple angles and common acoustic noise conditions—confirming practical feasibility. This work is the first to systematically establish wearable devices—particularly smartwatches—as critical enablers of ultrasonic side-channel attacks in air-gapped environments, providing a novel threat model and foundational insights for strengthening physical isolation security.

Technology Category

• Machine Learning: Hardware-aware ML
• Application Domains: Internet of Things, Sensor Networks & Smart Cities
• Planning, Routing, and Scheduling: Activity and Plan Recognition

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems

Abstract

Air-gapped systems are considered highly secure against data leaks due to their physical isolation from external networks. Despite this protection, ultrasonic communication has been demonstrated as an effective method for exfiltrating data from such systems. While smartphones have been extensively studied in the context of ultrasonic covert channels, smartwatches remain an underexplored yet effective attack vector. In this paper, we propose and evaluate SmartAttack, a novel method that leverages smartwatches as receivers for ultrasonic covert communication in air-gapped environments. Our approach utilizes the built-in microphones of smartwatches to capture covert signals in real time within the ultrasonic frequency range of 18-22 kHz. Through experimental validation, we assess the feasibility of this attack under varying environmental conditions, distances, orientations, and noise levels. Furthermore, we analyze smartwatch-specific factors that influence ultrasonic covert channels, including their continuous presence on the user's wrist, the impact of the human body on signal propagation, and the directional constraints of built-in microphones. Our findings highlight the security risks posed by smartwatches in high-security environments and outline mitigation strategies to counteract this emerging threat.

Problem

• Explores smartwatches as ultrasonic receivers for air-gap attacks
• Evaluates smartwatch vulnerabilities in covert ultrasonic communication
• Assesses environmental and hardware factors affecting attack feasibility

Innovation

• Smartwatches receive ultrasonic covert signals
• Utilizes 18-22 kHz frequency range microphones
• Assesses environmental and human body impacts