Hackers Use AI-Assisted CEO Emails to Trick Finance Teams Into Sending $50,000 Payments.
Microsoft tracked a million-message AI-assisted BEC campaign impersonating executives with fake ServiceNow invoices to steal ~$50,000 ACH payments.
Microsoft detected over one million messages in a BEC campaign running August 3-5, using AI-assisted phishing templates, executive impersonation, and fabricated ServiceNow subscription invoices to trick finance teams into authorizing fraudulent ACH payments of roughly $50,000. The US received 87.7% of volume. Attackers used lookalike domains like service-nowinc[.]com registered just days before delivery, with no compromise of ServiceNow itself. Telltale signs included verbose HTML comments, uniform formatting, and inconsistent forwarded-message headers.
Phishing Campaign Sends Millions of Emails Using Invisible Unicode to Evade Filters
Microsoft warns of a high-volume phishing campaign using invisible Unicode characters to split keywords like 'funding' and evade filters, peaking at 2.37 million daily messages.
Microsoft's Security Research team documented a high-volume phishing operation inserting deprecated Unicode Tags characters (U+E0000-U+E007F) inside financial keywords such as 'funding' so literal-string and regex email filters stop matching them. The campaign ran on a weekly cadence with 1-2.37 million weekday messages between February and May 15, 2026, peaking on February 26, 2026. It used hundreds of disposable finance-themed sender domains and relayed mail through ActiveCampaign's click-tracking infrastructure (acemlnd[.]com, activehosted[.]com), lending legitimate platform reputation. Microsoft ties the activity to an AI-assisted SBA loan phishing campaign that Fortra's FIRE team disclosed in September 2025.
ASCII smuggling crosses over from AI prompt injection to phishing evasion
Microsoft details high-volume phishing campaign using ASCII smuggling (Unicode tag chars) for filter evasion, peaking at 2.3M messages.
Microsoft researchers observed a high-volume finance-themed phishing campaign using invisible Unicode tag characters (U+E0000–U+E007F), a technique known from AI prompt injection research as ASCII smuggling, to split lure words like 'funding' and evade email filters. Telemetry from Microsoft Defender for Office 365 showed signature hits jump from roughly 21,000 messages on February 8, 2026 to more than 1.3 million on February 9, peaking above 2.3 million on February 11, with elevated weekday activity lasting approximately three months. The discovery emerged from prompt injection protection research, showing AI-era evasion techniques crossing into traditional phishing. Most messages were flagged by layered Defender protections rather than a single Unicode-specific signal.
Detect and disrupt AI-themed attacks with Microsoft Defender
Microsoft Threat Intelligence reports criminal campaigns impersonating ChatGPT, Copilot, Claude, and DeepSeek in phishing, AiTM, and malvertising attacks reaching 100,000 emails daily.
Microsoft Threat Intelligence observed a growing set of campaigns that abuse trust in popular AI brands: a ChatGPT-themed phishing campaign sent up to 100,000 emails in one day to steal payment card data, and a Claude-themed campaign used adversary-in-the-middle techniques to harvest credentials and access tokens. Other campaigns included malvertising for a fake AI Windows plugin delivering the Vidar stealer and fraudulent DeepSeek installers distributed via GitHub. Initial access broker Storm-3075 used AI-themed malvertising to distribute payloads for multiple downstream actors, and Microsoft notes the AI services themselves were not compromised. Microsoft also details Defender protections such as Safe Links, Safe Attachments, and attack disruption against these multi-stage lures.
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).
Trezor: 347,000 users targeted in phishing attacks after Brevo breach
Trezor reported phishing after the Brevo breach targeted 347,000 newsletter subscribers, with 2,500 users clicking before the domain was taken down.
Threat actors who breached Trezor's third-party email provider Brevo on September 9, 2026 sent fake 'critical security alert' emails from [email protected] to 347,000 opted-in newsletter subscribers, claiming an STM32 microcontroller vulnerability exposed wallet seeds. The emails linked to a malicious app that asked users to enter their wallet backup; 2,500 users clicked before Trezor disabled the phishing domain within 20 minutes. Trezor also disclosed that a prior breach via logistics provider ShipMonk, exploited through a critical Metabase SQL injection zero-day, affected 81,000 customers and drew extortion emails from the ShinyHunters gang.