Technology > IT

Hard disk drives and operating systems can be damaged by sounds played over low-cost speakers embedded in computers or sold in stores, according to Dan Goodin, reporting for ars technica. 

A research team used sonic and ultrasonic sounds to disrupt magnetic HDDs as data were being read or written. The researchers demonstrated how the technique can be used in preventing video-surveillance systems from recording live streams. It took a mere 12 seconds to interrupt a 720p system made by Ezviz using sophisticated acoustic interference. A stock Western Digital 3.5 HDD stopped recording and was forced to reboot after being subjected to sounds that lasted for 105 seconds or more.  

Such disruptions were caused by a speaker hanging from a ceiling that was four inches above the surveillance system’s HDD. The researchers did not remove the casing or tampered with the surveillance system. They said the recorded data is susceptible to acoustic interference or vibration attacks. 

The technique can also be used in disturbing the performance of HDDs in desktop and laptop computers, forcing such machines to reboot to be able to work properly. For instance, it took just 45 seconds in inducing a Dell XPS 15 9550 laptop to become temporarily disabled by exposing the machine to a “self-stimulation attack," whereby malicious audio is played through the laptop’s built-in speaker. When the sound played for two minutes or more, the computer had to be rebooted for the drive to work properly again.

Audible sounds can cause an HDD’s head stack assembly to vibrate abnormally. The vibrations push the head far away from the center of the drive track to temporarily prevent writing. On the other hand, ultrasonic sounds can create false positives to an HDD’s shock sensor which is designed to prevent the drive head from crashing. This causes the drive to unnecessarily park its head. Besides being used against computers and surveillance systems, the researchers said the attack might also target medical devices that use magnetic HDDs.