A Monitor’s Ultrasonic Sounds Can Reveal What’s on the Screen August 23, 2018 https://www.wired.com/story/monitor-ultrasonic-sounds-reveal-content-side-channel/ Synesthesia: Detecting Screen Content via Remote Acoustic Side Channels (PDF): https://www.cs.tau.ac.il/~tromer/synesthesia/synesthesia.pdf
SonarSnoop Acoustic Side-Channel Attack Can Steal Touchscreen Interactions August 31, 2018 https://www.bleepingcomputer.com/ne...el-attack-can-steal-touchscreen-interactions/ SonarSnoop: Active Acoustic Side-Channel Attacks (PDF): https://arxiv.org/pdf/1808.10250v1.pdf
Interesting to see so many potential functions coming to light which can likely be realized with today's increased probing & testing this and that. Back on Windows 98 many of these matters were discussed but could only go so far since touchscreen tech was relatively new at the time.
This is clever and all, but ultrasonics don't penetrate all that well. So just don't let adversaries or their devices into your workspace