https://arstechnica.com/information-technology/2018/05/attackers-can-send-sounds-to-ddos-video-recorders-and-pcs/ >Attackers can cause potentially harmful hard drive and operating system crashes by playing sounds over low-cost speakers embedded in computers or sold in stores, a team of researchers demonstrated last week. >The attacks use sonic and ultrasonic sounds to disrupt magnetic HDDs as they read or write data. The researchers showed how the technique could stop some video-surveillance systems from recording live streams. Just 12 seconds of specially designed acoustic interference was all it took to cause video loss in a 720p system made by Ezviz. Sounds that lasted for 105 seconds or more caused the stock Western Digital 3.5 HDD in the device to stop recording altogether until it was rebooted.