Microsoft has added a new Exchange Server feature that automatically applies interim mitigations for high-risk security flaws to secure on-premises servers against incoming attacks and give admins more time to apply security updates.
The new Exchange Server component, aptly named Microsoft Exchange Emergency Mitigation service, builds upon Microsoft’s Exchange On-premises Mitigation Tool released in March to help customers minimize the attack surface exposed by the ProxyLogon bugs.
EM runs as a Windows service on Exchange Mailbox servers and it will be automatically installed on servers with the Mailbox role after deploying the September 2021 CU on Exchange Server 2016 or Exchange Server 2019.
Exchange service mitigation: disables a vulnerable service on an Exchange server.
“This new service is not a replacement for installing Exchange Server Security Updates, but it is the fastest and easiest way to mitigate the highest risks to Internet-connected, on-premises Exchange servers prior to installing applicable SUs,” the Exchange Team explained.
Admins can disable the EM service if they don’t want Microsoft to apply mitigations to their Exchange servers automatically.