A team of researchers from the Ben-Gurion University’s Cyber Security Research Center in Israel have developed a type of malware that is able to steal data from an air-gapped machine – which is a computer that is physically isolated from any network, including the internet – by listening to a PC’s cooling fans, according to a new research paper [PDF].
Dubbed “Fansmitter”, the software – if installed on an air-gapped machine – can control the CPU and chassis fans to create an acoustic waveform that renders binary data. A nearby microphone can record and decode this audio data, which can be transmitted at 900 bits/hour. Not great for sending large amounts of data, admittedly, but enough to steal passwords, keys, and basic text documents.
“Using our method we successfully transmitted data from [an] air-gapped computer without audio hardware, to a smartphone receiver in the same room,” the research paper reads. “We demonstrated the effective transmission of encryption keys and passwords from a distance of zero to eight meters, with [a] bit rate of up to 900 bits/hour. We show that our method can also be used to leak data from different types of IT equipment, embedded systems, and IoT devices that have no audio hardware, but contain fans of various types and sizes.”
Image courtesy of Wikimedia.
Would it work if one or more of the chassis fans were running off a molex adaptor, or fan controller?