Passkey-themed social engineering leads to identity and cloud compromise
Microsoft tracks ongoing cloud intrusions where passkey-themed helpdesk lures enable AiTM credential theft, MFA persistence, and SharePoint data theft.
Microsoft Security Research is tracking active cloud-based intrusions, observed since May 2026, that begin with helpdesk impersonation calls and SMS lures urging urgent passkey, MFA, or SSO updates. The lures lead to adversary-in-the-middle phishing or device-code authentication flows that capture credentials and session tokens or grant actor access, after which the actors add authentication methods, conduct Microsoft Graph reconnaissance, and download SharePoint and OneDrive content via REST APIs. Phishing domains embed victim organization names as subdomains (e.g., contoso.add-passkey[.]com), are often registered with Nicenic, and go operational within hours. Microsoft advises revoking sessions and removing unauthorized authentication methods for confirmed compromises.
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.
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.
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.
Inside Knight Office, a New M365 AiTM Phishing Kit
Huntress details Knight Office, a new AiTM phishing kit stealing Microsoft 365 session tokens and registering attacker-controlled devices.
Huntress investigated an August 18, 2026 adversary-in-the-middle attack using the Knight Office phishing kit, which captured Microsoft 365 session tokens via a DocuSign-style lure routed through a Monday.com tracking link and a compromised Joomla site. After token capture, the actor enrolled an unauthorized host in Microsoft Entra ID and bound a Windows Hello for Business key credential to the account. The kit's operator console, found at IP 104.37.188.94, is built on Python Flask and hosts at least 25 .vu phishing domains. Telemetry links the kit to at least nine token-replay logins in two weeks and roughly 700 reported lure emails since April.
Infostealer Logs Expose Replayable AI Tokens That Can Bypass MFA
Okta finds infostealer logs contain thousands of replayable AI session tokens and API keys, letting criminals bypass MFA and access services from Google, Anthropic and OpenAI.
Okta analyzed a 7 GB infostealer dump from August 2, 2026 covering 5,871 infected machines in 162 countries and found 555 of 44,791 JWTs related to AI services, plus 1,843 unexpired JWTs and JWEs (largely set by OpenAI via NextAuth.js) and 24 still-valid API keys for Google Gemini, OpenAI, Groq and OpenRouter. Valid session tokens and API keys can be replayed with anti-detect browsers like Camoufox to bypass credential and MFA checks, fueling an underground market for AI account access known as LLMjacking, where attackers rack up victims' AI compute bills. Some 17.7% of the JWTs contained plaintext PII usable for social engineering. Google's GTIG reported growing buyer demand for Claude, Gemini, Cursor and Devin credentials, and Mandiant handled an incident where an actor used an exposed GitHub PAT to deploy unauthorized AI infrastructure and scale high-performance compute.
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.
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.
The Top 4 Threats We Found by Investigating Every Alert for a Quarter
Prophet Security's quarterly threat report finds identity attacks made up roughly half of confirmed malicious activity, with stolen authenticated sessions bypassing conditional access controls.
Between May 1 and July 31, 2026, Prophet Security investigated every alert in customer environments immediately on arrival; about 7% of completed investigations were confirmed malicious. Direct account/session attacks made up roughly 18% of confirmed activity, with replayed authenticated sessions bypassing conditional access since no re-authentication occurs. Infostealer activity affected about a quarter of investigated organizations, mostly delivered via browsers through compromised websites, malicious ads, sponsored search results and ClickFix fake CAPTCHA gates, with payloads including Lumma Stealer, Vidar, HijackLoader and AsyncRAT. Credential phishing was the largest category at about 28%, with adversary-in-the-middle relays revealed by seconds-long MFA approvals from distant countries and MFA fatigue attacks exploiting automatic unlock policies.
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.
BigBear Microsoft 365 phishing service bypassed MFA at 258 organizations
The BigBear 2.0 phishing-as-a-service framework bypassed MFA to steal 5,000+ Microsoft 365 credentials across 258 organizations, CloudSEK researchers found.
CloudSEK researchers gained administrator access to the BigBear 2.0 control panel, finding the phishing-as-a-service operation ran 42 VPS nodes all configured to target Microsoft 365. The framework has been used to bypass multi-factor authentication at 258 organizations and harvest more than 5,000 credentials, indicating an active credential-theft campaign against enterprise tenants.
ThreatsDay Bulletin: Claude Security Plugin, Azure Priv-Esc, Kali365 MFA Bypass, FIFA Scams +15 More
BigBear phishing crew nets thousands of Microsoft 365 credentials
CloudSEC accessed the BigBear 2.0 phishing panel, finding 5,137 stolen Microsoft 365 records across 461 organizations, including 474 MFA-bypassed sessions.
CloudSEC researchers got inside the admin panel of BigBear 2.0, an Evilginx2-based phishing-as-a-service operation run by someone known as 'General Boss'. The panel contained 5,137 records tied to 461 organizations: 1,032 plaintext passwords and 4,148 session cookies, with 474 complete MFA-bypassed authentications. The adversary-in-the-middle proxy captures Microsoft 365 session cookies that can be replayed to access email, Teams, SharePoint, and OneDrive, potentially pivoting into Entra ID and federated SaaS. The operation was still active, used custom JavaScript to disable FIDO2/WebAuthn on phishing pages, and routed logins through a residential proxy pool spanning 69 countries.
CTM360 Uncovers Over 3,000 Recruitment Phishing URLs Using Browser-in-the
CTM360's RecruitTrap report documents 3,000+ recruitment phishing URLs using BitB windows to steal credentials and relay MFA.
CTM360 identified over 3,000 phishing URLs impersonating recruiters from more than 50 organizations across 14 sectors in the RecruitTrap campaign. Attacks use Browser-in-the-Browser popups with spoofed address bars to harvest Google and Facebook credentials and relay MFA prompts in real time. About 96% of pages used a Calendly theme, with infrastructure concentrated on AWS EC2 and hidden behind Cloudflare.
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).