Using the microphones and speakers that come standard in many of today's laptop computers and mobile devices, hackers can secretly transmit and receive data using high-frequency audio signals that are mostly inaudible to human ears, a new study shows.
Michael Hanspach and Michael Goetz, researchers at Germany's Fraunhofer Institute for Communication, Information Processing, and Ergonomics, recently performed a proof-of-concept experiment that showed that "covert acoustical networking," a technique which had been hypothesized but considered improbable by most experts, is indeed possible.
Their findings, detailed in a recent issue of the Journal of Communications, could have major implications for electronic security.
"If you have a high demand for information security and assurance, you would need to prepare countermeasures," Hanspach wrote in an email to Inside Science.
In particular, it means "air-gapped" computers — that is, computers that are not connected to the Internet — are vulnerable to malicious software designed to steal or corrupt data.
"This is indeed a newsworthy development," said retired Navy Capt. Mark Hagerott, a cybersecurity professor at the U.S. Naval Academy in Annapolis, Md.
"These arms races between defensive and offensive advanced technologies have been going on for [a long time], but now, with the low cost of writing code, it may get progressively more challenging to defend against," said Hagerott, who was not involved in the study.