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Hackers Pose as IT Support to Hijack Microsoft 365 Accounts With Fake Passkey Alerts
Microsoft warns of vishing campaigns by Storm-3121 and Storm-3032 hijacking Microsoft 365 accounts via fake passkey alerts, adding attacker-controlled MFA and exfiltrating cloud data.
Microsoft Security Research has tracked the campaign since May 2026: callers posing as IT helpdesk staff tell employees to urgently update passkeys, MFA, or SSO settings via domains such as add-passkey[.]com and contoso[.]add-passkey[.]com. The lures lead to adversary-in-the-middle phishing or device-code authentication flows that yield credentials, session tokens, or OAuth tokens, after which attackers enroll their own MFA methods for persistence and run Microsoft Graph reconnaissance. They then collect SharePoint, OneDrive, and sometimes Exchange Online data at deliberately low rates (often under 1,000 files or messages per hour), with python-httpx seen in high-volume file access. Microsoft attributes initial access tradecraft to Storm-3121 and Storm-3032, linked respectively to ShinyHunters/Falcon and BlackFile/Helix extortion operations.
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Passkey-themed phishing attacks lead to Microsoft 365 data theft
Microsoft links ShinyHunters- and Helix-affiliated actors to passkey-themed vishing and device-code phishing that compromises Microsoft 365 accounts and steals cloud data.
Microsoft attributes passkey- and SSO-themed social engineering activity, observed since May 2026, to Storm-3121 (linked to ShinyHunters and Falcon) and Storm-3032 (tied to BlackFile members now operating as Helix). Attackers impersonate corporate IT help desks by phone or SMS, urging fake passkey, MFA, or SSO updates and directing victims to adversary-in-the-middle phishing pages or device-code authentication flows that yield credentials, session tokens, and OAuth tokens. Post-compromise behavior includes Microsoft Graph enumeration of users, SharePoint, and OAuth grants, plus persistence via attacker-controlled MFA methods. Google Threat Intelligence tracks related activity as UNC6671, linked to the BlackFile, Helix, Falcon, Pink, and Redact extortion gangs.
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BigBear Microsoft 365 phishing service bypassed MFA at 258 organizations
CloudSEK found the BigBear 2.0 phishing-as-a-service platform bypassed MFA at 258 organizations and captured over 5,000 Microsoft 365 credentials.
CloudSEK researchers gained administrator access to the BigBear 2.0 phishing-as-a-service control panel and found it had exfiltrated 5,137 credential records, including 474 completed MFA-bypassed authentications, 1,032 plaintext passwords, and 4,148 session cookies across 3,331 victim IPs in 40+ countries. The Evilginx2-based AitM proxy intercepts credentials and authenticated session cookies, and custom JavaScript interferes with FIDO2/WebAuthn to force weaker authentication. The panel is leased to at least five affiliate operators via Telegram exfiltration bots, and geo-matched residential proxies cover 69 countries to evade detection.
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GhostCode Abuses Microsoft Entra Device Enrollment to Maintain Access After Token Revocation
eSentire exposes GhostCode, a device-code phishing kit that abuses Microsoft Entra device enrollment to persist even after stolen tokens are revoked.
eSentire's Threat Response Unit observed GhostCode campaigns in late August 2026, using BEC-style social engineering that impersonated procurement staff, including BJ's Wholesale Club, via Salesforce contact forms. Victims received password-protected HTML lures disguised as a FlipBook document portal, with junk-data padding, HTML comment injection, and AES-256-GCM encrypted redirects gated by anti-bot checks. The kit exploits the OAuth 2.0 device authorization grant, prompting victims to approve real Microsoft device-code sign-ins with MFA. Within 78 seconds of approval, attackers registered three Entra devices and obtained a Primary Refresh Token, so rogue device registrations persist even after session token revocation.
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Hackers Use Passkey-Themed Phishing to Hijack Microsoft 365 Accounts and Steal Cloud Data
Microsoft reports passkey-themed phishing campaigns hijacking Microsoft 365 accounts via AiTM and device-code flows, then exfiltrating cloud data.
Microsoft researchers identified passkey-themed phishing across cloud intrusions observed since May 2026, where callers posing as IT support direct victims to lookalike sign-in pages. The flows include adversary-in-the-middle phishing and device-code authentication, letting attackers capture usable sessions even when MFA succeeds, followed by rogue MFA registration for persistence. Attackers enumerate tenants via Microsoft Graph and collect SharePoint, OneDrive, and Exchange data at rates below 1,000 items per hour; lure domains include passkeyhelpdesk.com and setupmypasskey.com.
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Hackers Impersonate IT Support on Microsoft Teams to Take Control of Employee PCs
Microsoft warns of a human-operated campaign where attackers pose as IT support in Teams to gain remote PC control and reach domain controllers.
Microsoft Threat Intelligence observed attackers abusing Microsoft Teams external collaboration to impersonate IT/helpdesk staff, persuading employees to grant screen control via Quick Assist or RMM tools. Operators deploy malicious MSI packages via silent msiexec, run encrypted JavaScript implants through portable Node.js, and persist via EdgeUpdate Run keys or Startup folder entries. The Node.js backdoor uses HTTPS long-polling C2, captures screenshots, enumerates Active Directory, and moves laterally over WinRM (TCP 5985) to domain controllers and certificate authorities. Initial access maps to MITRE ATT&CK T1566.003 (Spearphishing via Service); no Teams vulnerability is exploited.
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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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