The mute button does not prevent the video calling software from listening to your microphone. Researchers from two American universities discovered this when they analyzed the mute buttons in programs like Skype, Teams, Zoom, and Slack. Cisco Webex was also investigated and found that it sends voice data to its servers for telemetry even when the microphone is muted.
We’ve tested it ourselves, and the mute button in Skype doesn’t really mute the mic at the driver level. This can be useful if the microphone is being used by several programs at the same time, but this allows the software to continue listening. According to the researchers, most of the tested apps do not use this option.
One exception is Cisco’s Webex, a video conferencing program for the job market. Webex was receiving data from the microphone every minute even when muted. This included data derived from the sound, such as the volume of background sounds. So there are no recorded audio tracks, but according to the research there is enough information to be able to determine what activities are taking place in the background.
Cisco responded to the results of the investigation. The company reported to news site The Register that it had adapted their software; No more microphone data will be sent to servers, except for information used for Webex’s mute notification feature.
The 21-page study of the mute buttons is available online in PDF format on the Wisconsin Privacy and Security Group website.
Sources: “Are you really quiet?” work (PDF), The Register
Source: Hardware Info
