New Air-Gap Jumper Covertly Transmits Data in Hard-Drive Sounds (arstechnica.com)
Security researchers have found a new way to siphon data out of an infected computer even when it has been physically disconnected from the Internet -- otherwise known as "air-gap" computers -- to prevent the leakage of sensitive information it stores, reports ArsTechnica. From the article: The method has been dubbed "DiskFiltration" by its creators because it uses acoustic signals emitted from the hard drive of the air-gapped computer being targeted. It works by manipulating the movements of the hard drive's actuator, which is the mechanical arm that accesses specific parts of a disk platter so heads attached to the actuator can read or write data. By using so-called seek operations that move the actuator in very specific ways, it can generate sounds that transfer passwords, cryptographic keys, and other sensitive data stored on the computer to a nearby microphone. The technique has a range of six feet and a speed of 180 bits per minute, fast enough to steal a 4,096-bit key in about 25 minutes.
Considering that people play music with floppy drives then the ability to transfer information acoustically with hard drives isn't really different.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.