After the pandemic Remote operation And distance learning has become the new norm for millions of people. To achieve this they had to use video calling platforms like Zoom, Skype, TeamsBy the way, which allows the camera and microphone to be turned off, however, Is the microphone really off?

One of the features of these platforms is to turn off video and audio so that external conversations are not filtered or awkward to view. The popularity of these apps has prompted security experts to check how secure they are.

Kaspersky, Cyber ​​Security Company, Analyzed whether the microphone mute function in various applications does not actually filter audio; Find important results that are worth considering.

To conduct the investigation, the specialists asked themselves, how is this function actually performed? Whether there is a microphone sound on the program serverWhile silent mode is on? And to answer that, the researchers analyzed the microphone performance in a total of ten services, based on calls made through the browser.

What were the consequences

This was announced by the Cyber ​​Security Company in its tests Used an open source browser As in the case of Chromium (the basis of many browsers such as Google Chrome and Microsoft Edge).

The goal was to make all services comply with the microphone interaction rules set by the browser engine developers. That is, when the microphone mute button is activated in the web interface, the service should not receive a sound. Desktop native apps have more permissions.

The result, as expected, he was Each program has a different behavior. The results of each video calling platform were as follows:

Zoom in

It is reliable: The microphone mute mode does not listen to what is happening around you. In addition, it regularly requests information that allows it to determine the noise level close to the microphone. As soon as he finds a noise or sound, he remembers, as always, that the audio needs to be activated.

Microsoft teams

Things get a little more complicated. Instead, Microsoft Teams does not use the standard system interface for microphone interaction Directly related to Windows. For this reason researchers Could not find out in detail How to manage silent mode during a call.

cisco-webex

It continuously processes the sound during a call from the microphone, regardless of the audio status inside the app (on or off). Researchers have found that Webex is not observed as such because in silent mode! The voice is not transmitted. But it sends metadata such as signal volume level.

It seems to be somewhat disturbing. However, they were able to guess a number of key parameters of what was going on in the user environment. For example, It was possible to determine which customer was connected to the work call, turned off the microphone and camera, and cleaned with a vacuum cleaner, preparing if there was a dog barking. Close.

Until They were able to tell if there were other people in the room (E.g., to determine if a call came from a public place). Specialists used an algorithm similar to Shazam and other music recognition apps. A set of templates was created for each “noise sample” and compared with data from a Cisco Webex client.

It should be noted that The real danger is not these tools, but rather Malicious program Who can track victims and send audio recordings of these conversations. In this case, you not only need a security solution that deals with unwanted programs, but also a means to control who accesses the microphone and when.

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