Microsoft has come up with a release of a one-click mitigation tool help businesses from the zero-day attacks against on-prem Exchange Servers. By downloading and running this tool, which includes the latest Microsoft Safety Scanner, customers will automatically mitigate CVE-2021-26855 on any Exchange server on which it is deployed. This tool is not a replacement for the Exchange security update but is the fastest and easiest way to mitigate the highest risks to internet-connected, on-premises Exchange Servers prior to patching.
The EOMT tool nce run, the Run EOMT.ps1 tool will perform three operations:
Microsoft Exchange Server
Microsoft recommends following