If you run the Shazam song identification app an Mac, the mic will never switch off, even when the program reports that it has.
The makers of the app confirm that this is deliberate, a design choice to make Shazam more responsive, without any delay as the OS initializes the mic. They also report that this behavior is present with Ios, Apple's mobile operating system. They say that though the mic is taking in sound when in the off position, that input is discarded without further processing.
The behavior was discovered by Patrick Wardle, whose Oversight tool monitors the status of the mic and camera to detect their covert operation. An Oversight user informed Wardle that Oversight was being triggered when Shazam was running, and Wardle published an investigation into the program's ability to override the operating system.
"I saw no indication that this recorded data is ever processed (nor saved, exfiltrated, etc)," Wardle wrote in his blog post, which he shared with Motherboard in advance. "However, I still don't like an app that appears to be constantly pulling audio off my computer's internal mic."
For Wardle, that's not good because a piece of malware could inject into the app and piggyback on this feature to surreptitiously record the user, without prompting an alert. And Shazam could change the way the app works and ad "as users we are just going to have to trust they won't."
So is Shazam keeping your mic always-on—even when you switch the app off—a feature or bug? That's up to you to decide. Far what it's worth, Wardle said he deleted the app.
Forget the NSA, it's Shazam that's always listening!
[Patrick Wardle/Objective See]
Shazam Keeps Your Mac's Microphone Always On, Even When You Turn It Off