"Microsoft Defender will automatically prevent Exchange server exploits. A security update for Defender will mitigate CVE-2021-26855 on vulnerable Exchange servers. Microsoft has been rolling out one security measure after another ever since it discovered that bad actors have been exploiting four zero—day flaws in Exchange Server. Its latest step is updating the Microsoft Defender Antivirus so that it automatically mitigates CVE-2021-26855, which is the most critical vulnerability among the four. Since it serves as the entry point to be able to exploit the three other flaws, preventing perpetrators from being able to take advantage of it takes priority...." https://www.engadget.com/microsoft-defender-prevent-exchange-server-exploits-191547916.html
