Connect with us

Hi, what are you looking for?


IoT Security

Power Supply Can Turn Into Speaker for Data Exfiltration Over Air Gap

A researcher has demonstrated that threat actors could exfiltrate data from an air-gapped device over an acoustic channel even if the targeted machine does not have any speakers, by abusing the power supply.

A researcher has demonstrated that threat actors could exfiltrate data from an air-gapped device over an acoustic channel even if the targeted machine does not have any speakers, by abusing the power supply.

Some isolated systems may have their audio hardware disabled in an effort to prevent stealthy data exfiltration. However, researcher Mordechai Guri from the Cyber-Security Research Center at the Ben-Gurion University of the Negev in Israel has shown that a piece of malware can cause a device’s power supply unit to generate sounds that can be picked up by a nearby receiver.

The malware, which requires no special permissions, can modulate information from the air-gapped device over the acoustic signals and send them to a smartphone that “listens.” This method can be used to exfiltrate passwords, encryption keys, and files from PCs, servers and even IoT devices that have no audio hardware.

Tests conducted by Guri have shown that the attack method, which he has dubbed POWER-SUPPLaY, can be used to steal data from an air-gapped system over a distance of up to 5 meters (16 feet) with a maximum transfer rate of 50 bits per second — the transfer rate decreases as the distance increases.

The attack involves starting and stopping the CPU workload, which influences the switching frequency of the power supply, which in turn impacts the transformers and capacitors in the power supply. These transformers and capacitors generate acoustic signals (i.e. noise).

Guri showed that a piece of malware able to control a device’s CPU workload can accurately cause the power supply to generate both audible and inaudible sounds. The researcher demonstrated that a power supply can play the song “Happy Birthday” using this method.

Of course, a piece of malware whose goal is to silently exfiltrate data would not play any sound that would attract attention. Instead, it would play audible or inaudible sounds on two or more different frequencies, each frequency representing a 0 bit, a 1 bit or a sequence of bits (e.g. 00, 01, 10, 11) that will be captured by a receiver.

The receiving smartphone can be owned by the attacker or it can be a compromised device belonging to someone who works in the targeted organization.

Advertisement. Scroll to continue reading.

This is not the first time a researcher from the Ben-Gurion University of the Negev has demonstrated a method for exfiltrating data from air-gapped devices. Over the past years, they showed techniques for silently stealing data using fan vibrations, heat emissionshard drive LEDsinfrared camerasmagnetic fieldspower linesrouter LEDsscannersscreen brightnessUSB devices, and noise from hard drives and fans.

Related: Hackers Can Steal Data From Air-Gapped Computers Via Screen Brightness

Related: China-linked Hackers Targeting Air-Gapped Systems: Report

Related: Hackers Can Steal Cryptocurrency From Air-Gapped Wallets: Researcher

Written By

Eduard Kovacs (@EduardKovacs) is a managing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

Join us as we delve into the transformative potential of AI, predictive ChatGPT-like tools and automation to detect and defend against cyberattacks.


As cybersecurity breaches and incidents escalate, the cyber insurance ecosystem is undergoing rapid and transformational change.


Expert Insights

Related Content

Identity & Access

Zero trust is not a replacement for identity and access management (IAM), but is the extension of IAM principles from people to everyone and...


Less than a week after announcing that it would suspended service indefinitely due to a conflict with an (at the time) unnamed security researcher...

Data Breaches

OpenAI has confirmed a ChatGPT data breach on the same day a security firm reported seeing the use of a component affected by an...

Risk Management

The supply chain threat is directly linked to attack surface management, but the supply chain must be known and understood before it can be...

IoT Security

A group of seven security researchers have discovered numerous vulnerabilities in vehicles from 16 car makers, including bugs that allowed them to control car...


A researcher at IOActive discovered that home security systems from SimpliSafe are plagued by a vulnerability that allows tech savvy burglars to remotely disable...


Patch Tuesday: Microsoft warns vulnerability (CVE-2023-23397) could lead to exploitation before an email is viewed in the Preview Pane.


Patch Tuesday: Microsoft calls attention to a series of zero-day remote code execution attacks hitting its Office productivity suite.