Security News > 2020 > December > How to leak data via Wi-Fi when there's no Wi-Fi chip: Boffin turns memory bus into covert data transmitter

In a newly released working paper [PDF], "AIR-FI: Generating Covert Wi-Fi Signals from Air-Gapped Computers," Guri, head of research and development at Ben-Gurion University of the Negev, Israel's Cyber-Security Research Center, describes a technique for turning DDR SDRAM buses into transmitters that can spew sensitive data.

It's a method for sending data via Wi-Fi signals when the target device doesn't have Wi-Fi capability.

"Since the clock speed of memory modules is typically around the frequency of 2.4 GHz or its harmonics, the memory operations generate electromagnetic emissions around the IEEE 802.11b/g/n Wi-Fi frequency bands," the paper explains.

For memory modules where that's not the case, the setup malware would need to overclock or underclock the memory speed to generate emissions in the frequency of Wi-Fi bands or their harmonics.

Guri suggests various potential defenses, such as not allowing network-capable devices near air-gapped hardware, implementing Wi-Fi jamming, muddying any potential covert Wi-Fi signal with a background process running random memory/CPU operations, and Faraday shielding.

News URL

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