MC234252 - Configuration Change in Guest access for Microsoft Teams
Author: Microsoft
…Beginning on February 8th, 2021, we are turning on Guest access in Microsoft Teams by default for any customers who have not configured this setting…
…if you want Guest access to remain disabled for your organization, you will need to confirm that the Guest access setting is set to "Off" instead of "Service default"…
Because MSFT Admin notices are not posted in a public facing site, I am attaching a PDF of the notice below. Cyber threats and indirect hacking attempts have blossomed in the pandemic remote working age. I brought this change up to cyber security guru John Wilson (HaystackID) on a webinar prep call today. He commented that this could be the equivalent of ‘rolling out the red carpet to hackers’. Many corporate sales/marketing/PR/shareholder relations teams are using Teams externally. All it takes is guest access and weak default Teams permissions to invoke/transmit malicious code to jump to a critical internal target.