Why Your Business Needs to Analyze Sound Waves?
Theoretically, a computer that's not a physical network, Wi-Fi signal or Bluetooth should be completely inaccessible in a network security method known as an "air-gapped". However, in 2010, security consultant Dragos Ruiu discovered that one of his air-gapped computers had been infected with malicious software that replaced his Basic I/O System (known for "BadBIOS"), the basic software that controls hardware and loads the operating system. Even after he removed the wireless and Bluetooth components, the malware kept reinstalling itself after being wiped. In the end, he discovered the source: high-frequency sound waves inaudible to humans.
The sound is transmitted from one device to another, using the computer's microphone to translate sound waves into data. While Ruiu's claims sounded like science fiction, the method which can transmit data from up to 64 feet away was later proven to work by two German scientists who had been researching (PDF) the topic separately.
It's currently not clear whether affected machines had to have been already infected with malware, for instance through a USB stick, or if the sound waves can directly infect a computer. The virus could potentially be prevented, however, by installing a low pass filter that blocks out high-frequency sounds, the paper states.
