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.
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).
BigBear 2.0 Evilginx2 Phishing Campaign Bypasses Microsoft 365 MFA With Session Cookie Theft
CloudSEK identified BigBear 2.0, an Evilginx2-based AiTM phishing operation stealing Microsoft 365 MFA session cookies, hitting 461 organizations across 40-plus countries.
The campaign proxies Microsoft sign-in pages to capture credentials and authenticated session cookies, enabling session replay into email, Teams, SharePoint, OneDrive, and connected SSO applications. CloudSEK's June 2026 discovery found 5,137 stolen records, 1,032 passwords, and 4,148 session cookies tied to 3,331 victim IPs, linked to operator 'General Boss' across 42 VPS nodes. The operation targeted IT services and managed service providers, used country-matched residential proxies, and involved at least five affiliates.
IT Help Desk Impersonation Lets Hackers Bypass MFA
Arctic Wolf tracks PREY-0058 posing as IT help desk to steal Microsoft 365 sessions via AiTM panels, then extorting executives after SaaS data theft.
Arctic Wolf documented a threat cluster tracked as PREY-0058 that impersonates internal IT help desk staff by phone, luring Directors, VPs, and executives to authentication-themed URLs formatted as victim-organization lure domains. Adversary-in-the-middle panels intercept credentials and MFA approvals, and stolen sessions are replayed through residential proxies such as NodeMaven from IPs matching the victim's geo-location and ASN, defeating impossible-travel alerts. Attackers perform discovery against SharePoint and Entra ID, then harvest data from OneDrive, Exchange, and Box before issuing extortion demands. Defenders are advised to require managed devices, use phishing-resistant MFA like FIDO2, enable Continuous Access Evaluation, and monitor sign-ins, SharePoint SearchQueryPerformed, and MailItemsAccessed events.
UNC6671 Vishing Attacks Target Personal Phones to Steal SaaS Data
Google and Mandiant attribute vishing-based SaaS data extortion attacks to UNC6671, now operating under the Redact, Pink, Helix, and Falcon brands.
Google Threat Intelligence Group and Mandiant track extortion group UNC6671, which uses vishing calls impersonating IT help desks to lure employees to adversary-in-the-middle phishing pages that capture credentials, MFA tokens, and session tokens. The group then registers adversary-controlled MFA devices, pivots through identity providers into Microsoft 365, Okta, and other SaaS applications, and runs automated Python and PowerShell exfiltration scripts. UNC6671 has rotated through extortion brands including BlackFile, Redact, Pink, Helix, and Falcon, and Google tracked over $10.6 million in Bitcoin payments between January 7 and May 12, 2026, with initial demands exceeding $3 million. The actor has hit dozens of organizations in North America, Australia, and the UK, shifting toward high-value financial and legal firms in July 2026.
GhostCode Phishing Kit Bypasses Microsoft 365 MFA to Hijack Accounts in 78 Secondsnew
eSentire identified GhostCode, a phishing kit abusing Microsoft 365 OAuth device-code sign-in to steal tokens and take over accounts in seconds.
eSentire analysts identified GhostCode in late August, a phishing kit that uses business contact-form messages and an NDA pretext to deliver a password-protected HTML attachment leading victims to a Microsoft device-code sign-in. Victims authenticate on legitimate Microsoft pages, letting the kit obtain a Primary Refresh Token in 32 seconds and register three devices in 78 seconds, with residential proxies matching the victim's location. The kit hides its redirect with encrypted addresses, junk data, and scanner-filtering challenges, and uses GHOSTnet-linked infrastructure during device enrolment. eSentire recommends blocking device-code authentication via Conditional Access, invalidating tokens, and reviewing newly enrolled devices.