(sekoia.io) EvilTokens: A New Phishing-as-a-Service Platform Weaponizing Microsoft Device Code Authentication
New PhaaS platform EvilTokens weaponizes Microsoft OAuth 2.0 Device Code flow for large-scale M365 account takeovers. Active since Feb 2026, it enables BEC operators to harvest refresh tokens, convert them to PRTs, and hijack SSO sessions without MFA.
In brief - EvilTokens is a Phishing-as-a-Service platform exploiting Microsoft device code authentication to enable persistent Microsoft 365 account access. It has been adopted by BEC threat actors globally, leveraging Telegram bots and Cloudflare Workers to deliver phishing pages impersonating Adobe, DocuSign, and SharePoint.
Technically - EvilTokens abuses the OAuth 2.0 Device Authorization Grant using first-party client IDs (e.g., Microsoft Office). The backend exposes REST API endpoints for device code initiation (/api/device/start), token polling (/api/device/status/:sessionId), PRT conversion (/api/prt/convert), and OWA session cookie generation (/api/prt/owa-session). Harvested refresh tokens are converted to PRTs, enabling silent SSO hijacking via x-ms-RefreshTokenCredential cookies. Phishing pages use AES-GCM encrypted HTML with an X-Antibot-Token header for bot detection. Tracking via URL patterns, headers, and provided YARA rules is possible.
Source: https://blog.sekoia.io/new-widespread-eviltokens-kit-device-code-phishing-as-a-service-part-1/
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