Flaws in Videoconferencing Systems Put Boardrooms at Risk
nytimes.com
nytimes.com
That said, there would likely still be indicators that there was an active video. Unless they were able to compromise the firmware also, which is less likely than simply port 5060 being open. Many of the systems are on a URI/IP dialing system and the port may be left open intentionally. So it's bad - but not 'dozens of listeners listening at all times without anyone having a clue' bad (hopefully).