Microsoft's Top Execs' Emails Breached in Sophisticated Russia-Linked APT Attack

Microsoft disclosed that a Russian-linked APT (Midnight Blizzard / APT29) conducted a password-spray campaign beginning in late November 2023 that compromised a legacy non-production test tenant, allowing the adversary to access and exfiltrate emails and attachments from a small percentage of corporate accounts—including senior leaders and employees in cybersecurity and legal—discovered and mitigated on January 12, 2024; Microsoft emphasized no evidence of customer, production, source-code, or AI-system access.