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.
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.
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.
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.
Risky Bulletin: BEC campaign steals €35 million from French notaries
Hackers stole over €35 million from 500+ French notary offices in a four-year BEC campaign; ANSSI spent two years helping evict the attackers.
A business email compromise campaign breached more than 500 French notary offices — about 7% of all French notaries per the Conseil Supérieur du Notariat — over four years, stealing more than €35 million by phishing initial access and silently modifying wire transfer details. France's cybersecurity agency ANSSI worked for two years behind the scenes to help notaries remove the persistent attackers, who had deep access; officials also feared hackers could issue fake notarized acts such as marriage certificates or forged real estate deals. No forged documents have been found so far, but notaries have added two-factor authentication and in-person requirements for banking details, and banks added extra checks in 2024. The newsletter also notes other incidents, including a $320 million Bitcoin extraction from Blockstream's Liquid Network and a JetBrains Cadence breach via TeamCity servers.