Ddos 
A study by Mordechai Guri of Ben-Gurion University unveils a chilling new vector for data exfiltration: smartwatches. Dubbed SmartAttack, this method turns a wearable into a covert ultrasonic receiver, capable of siphoning data from even the most secure, air-gapped systems.
“Smartwatches—despite their growing popularity and frequent presence in high-security environments—remain largely unexplored in this context,” Guri notes.
Air-gapped systems, isolated from external networks, are considered among the most secure. Yet, this isolation isn’t impenetrable. Previous work has shown that acoustic and ultrasonic channels can serve as invisible bridges for data leaks. What sets SmartAttack apart is its weaponization of something nearly ubiquitous in corporate environments: wearable tech.
SmartAttack transmits data via ultrasonic waves (18–22 kHz)—inaudible to humans but perfectly readable by smartwatches equipped with sensitive microphones. These signals can carry keystrokes, encryption keys, or login credentials without ever connecting to a network.
The attack unfolds in two main stages: infiltration and exfiltration.
- Infiltration: Malware is covertly introduced into a secured workstation—possibly via USB, insider threat, or supply chain compromise. Concurrently, a smartwatch worn by an employee or visitor is infected, enabling it to “listen” for ultrasonic signals.
- Exfiltration: The compromised PC uses its speakers to emit modulated ultrasonic signals. The smartwatch detects, decodes, and transmits the stolen data to the attacker via Bluetooth, Wi-Fi, or a paired device.
“The compromised computer transmits sensitive information, such as keystrokes, modulated onto ultrasonic signals, which are received and processed by the smartwatch,” the paper explains.
The inherent stealth of smartwatches makes them ideal espionage tools. Unlike smartphones that may be left behind or placed on a desk, smartwatches are worn continuously. This not only brings them physically closer to air-gapped systems but also removes suspicion—after all, who would question a wristwatch?
Still, there are technical challenges. Smartwatches have lower-quality microphones, less processing power, and their constant motion (e.g., wrist movements) can distort signals. But Guri’s research proves they are still effective for covert communication, especially at lower transmission rates.
“Despite these limitations, smartwatches offer significant advantages in covert communication due to their constant presence on the user’s wrist, minimizing detection risks.”
The SmartAttack system was tested using various types of speakers and transmission rates. The results?
- Active speakers achieved data transmission up to 9 meters at 5 bits per second (bps) with high reliability.
- Laptop speakers, though less powerful, maintained signal integrity up to 6 meters.
- Smartwatches could accurately receive and decode transmissions even in noisy environments, thanks to refined signal processing techniques using FFT, Kalman filtering, and spectral subtraction.
Stopping ultrasonic exfiltration isn’t easy. Traditional firewalls and antivirus software won’t detect sound waves. But there are strategies:
- Ban smartwatches and audio-capable wearables from secure areas.
- Deploy ultrasonic monitoring systems to detect covert transmissions.
- Use jamming devices to flood the environment with ultrasonic noise.
- Physically disable microphones and speakers (audio-gapping) in critical systems.
Security professionals must now consider smartwatches not just as fitness trackers or notification tools, but as potential espionage devices.
“Our analysis highlights smartwatch-specific factors… introducing both operational constraints and advantages compared to previously studied ultrasonic receivers.”
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