Microsoft Defender for Office 365 is introducing Mail Bombing Detection to protect against email bombing attacks. This feature will be available worldwide from late June to early July 2025. It will automatically identify and block such attacks, sending them to the Junk folder without manual configuration. Inform your security team and update documentation accordingly.
Applies to: Exchange Online · Microsoft Defender XDR
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).