Microsoft Exchange's security is "Swiss-cheese"

Wow! Microsoft have had a really bad start to 2021. What does that mean for its customers? What we do know is that if you’re using on-premise Microsoft Exchange servers and use Outlook Web Access (or OWA) , since at least early January 2021 until early March 2021 (or beyond if you hadn’t yet patched AND done a post-patch security audit of your network) there is a very good chance that your data has been exposed or worse that your Microsoft Exchange servers and/or your entire internal Microsoft Windows Server network is compromised.
This is a companion discussion topic for the original entry at https://dominopeople.ie/microsoft-exchanges-security-is-swiss-cheese/