Stopping Spam Sent from Bad Microsoft 365 Domains
Anecdotal evidence is that some spam originates from onmicrosoft.com domains. These are the domains used by Microsoft 365 tenants and the spam indicates that attackers sign up for 'disposable' tenants to send their malware. This article describes what onmicrosoft.com domains are and how to use a mail flow rule to control their traffic.
February 26, 2024