Tycoon2fa

Detects a sequence of events in Google Workspace where OAuth authorization from a suspicious ASN is immediately followed by device registration, potentially indicating attacker-controlled device enrollment after user authorization of a sensitive client, possibly related to Tycoon2FA.

This rule detects Microsoft 365 audit events indicative of Tycoon 2FA phishing-as-a-service (PhaaS) adversary-in-the-middle (AiTM) activity, identifying UserLoggedIn events where the Microsoft Authentication Broker requests access to Microsoft Graph or Exchange Online, or the Office web client application authenticates to itself, combined with Node.js-style user agents, bypassing MFA by relaying authentication and capturing session material.

Detects Microsoft Entra ID sign-ins consistent with Tycoon2FA phishing-as-a-service (PhaaS) adversary-in-the-middle (AiTM) activity targeting Microsoft 365 and Gmail, where the Microsoft Authentication Broker requests tokens for Microsoft Graph or Exchange Online, or the Office web client application authenticates to itself, combined with Node.js-style user agents (node, axios, undici).

The Tycoon2FA phishing kit now supports device-code phishing attacks targeting Microsoft 365 accounts, abusing Trustifi click-tracking URLs, redirecting victims through Cloudflare Workers to a fake Microsoft CAPTCHA page, tricking them into entering a device code, and granting attackers OAuth tokens and access to their Microsoft 365 accounts.

In Q1 2026, email threats increased, including credential phishing, QR code phishing, and CAPTCHA-gated campaigns, with Microsoft's disruption of the Tycoon2FA phishing platform leading to a 15% volume decrease and shifts in threat actor tactics; BEC activity remained prevalent at 10.7 million attacks.