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Protecting organizations from AI-assisted executive impersonation and invoice fraud
Microsoft tracked a campaign of over one million AI-crafted CEO-impersonation emails seeking ~$50,000 ACH payments with fabricated ServiceNow invoices.
Between August 3 and 5, Microsoft detected a campaign of more than one million fraud emails, 87.7% of them targeting US enterprise users, sent through multiple third-party email delivery service accounts. The actor impersonated CEOs, CFOs, and presidents of targeted companies, urging accounts payable staff to process an ACH payment of nearly $50,000. Lures layered executive impersonation, lookalike domains, a fabricated ServiceNow 'Annual Subscription' invoice personalized to the recipient, and forged forwarded email threads; Microsoft found no evidence ServiceNow or the referenced executives were compromised. Microsoft observed indicators consistent with generative AI-assisted template creation, while leftover inconsistencies such as missing forwarding headers and mismatched display names gave defenders detection cues.
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BigBear 2.0 phishing campaign hijacks Microsoft 365 sessions after MFA
CloudSEK uncovered BigBear 2.0, a PhaaS operation that captured 4,148 Microsoft 365 session cookies, hijacking authenticated sessions after MFA via AiTM proxy.
CloudSEK infiltrated the BigBear 2.0 phishing-as-a-service panel in June, finding 5,137 credential records tied to 461 organizations in over 40 countries, including 4,148 captured session cookies and 474 completed post-MFA logins. The operation, built on Evilginx2, uses an attacker-controlled reverse proxy to steal authenticated session cookies and residential proxies to defeat location-based Conditional Access checks, while custom code disables FIDO2/WebAuthn on phishing pages. At least five affiliates operated 42 VPS nodes, with IT services and managed service providers the most targeted sector.
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Attackers Use Passkey Phishing to Hijack Microsoft Cloud Accounts and Exfiltrate Data
Microsoft details two campaigns: million-email CEO impersonation ACH fraud and passkey-themed vishing that hijacks Microsoft cloud accounts for data theft and extortion.
Microsoft disclosed a campaign that sent over one million CEO-impersonation scam emails between August 3-5, 2026, targeting U.S. accounts payable departments with fake ServiceNow subscription invoices to induce ACH transfers, using generative AI to tailor templates. A second campaign detected since May 2026 uses passkey/MFA-themed voice phishing posing as the IT help desk, redirecting victims via SMS to counterfeit Microsoft sign-in pages and adversary-in-the-middle or device-code flows to hijack accounts. Post-compromise activity includes adding attacker-controlled authentication methods, high-volume Microsoft Graph activity, SharePoint and OneDrive downloads, and mailbox collection via REST APIs. Microsoft attributes initial access to Storm-3121 (linked to ShinyHunters and Falcon extortion) and Storm-3032 (UNC6671, a BlackFile splinter operating the Helix extortion brand).
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