The U.S. National Security Agency (NSA) recently discovered additional security vulnerabilities in Microsoft Exchange Server 2013 through 2019.
In response, Microsoft released yesterday more security updates for these systems. It is critical that you patch these systems immediately because Microsoft expects threat actors will exploit these vulnerabilities soon. Exchange Online customers are already protected and do not need to act.
To protect your organization, update your Exchange Server.
You can get the Microsoft updates here.
Interested to learn more? Read our article from the beginning of March which explained what happened.