The fans that accompany the computer cases and that serve to cool and protect the life of its components, produce subtle vibrations that go unnoticed by our human ears. Now, a team of researchers from the Ben-Gurion University of the Negev (Israel) has discovered a creative way in which computer scientists can steal sensitive data from a highly secure computer. How is it possible? Taking advantage of the vibrations of a cooling system fan.
A new form of cyberattack
Cybersecurity principal investigator Mordechai Guri from the Israeli university explained that data encoded by hackers in fan vibrations could be transmitted to a compromised smartphone or smartphone located near the target computer.
“We observed that computers vibrate at a frequency correlated with the rotation speed of their internal fans,” Guri said. “Malware can control computer vibrations by manipulating the internal speeds of the fan. These inaudible vibrations affect the entire structure in which the computer is placed.”
Thanks to this new cyberattack method, it is possible to connect the phone with a PC without any wired or wireless connection and transfer this information to a nearby compromised mobile phone. Accelerometer sensors on smartphones are unsecured and “can be accessed by any application without requiring user permissions, making this attack very evasive.”
The vulnerability that uses changes in the vibrations of PC fans to filter data through a complex method that involves more than one compromised device, has been dubbed Air-ViBeR.
Should we be concerned?
There is an infinitesimal and purely mathematical possibility that this type of cyberattack affects us, however, it must be recognized that, above all, it is a very ingenious method, worthy of a Hollywood hacker movie.
The Air-ViBeR technique regulates the speed of the fans to alter the acoustics of the computer quickly, without our being able to realize it, to transmit data to a listening device connected to the Internet that then converts those vibrations into ones and zeros that can transmit to network.
Yes indeed; there is no way by which this method can transmit our hard disk C: of 100 gigabytes (or similar) of all life, and much less during the few hours that the smartphone is placed on the same desk as the computer , but the attacker would look for something specific; data that will wrap to about 4KB (one block or 32,768 bits) for easy grabbing and transmission.
“The malware in question does not filter data by breaking encryption standards or by breaking a network firewall , but encodes the data in vibrations and transmits them to the accelerometer of a smartphone,” Guri clarifies.
How to protect ourselves
Although it is practically unfeasible -because it is an investigation-, three measures would help protect a computer against this cyberattack :
- Running the CPU continuously in the maximum power consumption mode, which would prevent it from adjusting the consumption.
- Set CPU and GPU fan speeds to a single, fixed speed.
- Restrict the CPU to a single clock frequency.
Mordechai Guri, demonstrated his method and wrote a paper explaining what he calls “covert air gap channels” in an article posted on arXiv.
Referencia: AiR-ViBeR: Exfiltrating Data from Air-Gapped Computers via Covert Surface ViBrAtIoNs, arXiv:2004.06195 [cs.CR] https://arxiv.org/abs/2004.06195v1
