Microsoft Purges Millions of Cloud Tenants in Wake of Storm-0558

Microsoft's Secure Future Initiative (SFI) responds to the Storm-0558 nation-state breach of Exchange Online and a later password-spraying attack by Midnight Blizzard; Microsoft reports removing 550,000 inactive Azure tenants, inventorying >99% of network assets and pipelines, standardizing Entra ID token validation with a hardened SDK, migrating signing keys to HSMs and confidential VMs, enforcing MFA and access controls, and reducing admin roles—while external experts note remaining gaps and the need for continued improvements.