MFA now even more vulnerable

markus.preinl • 26. Februar 2026
Adversary-in-the-Middle-attack (AiTM-attack)

Capturing session tokens isn't entirely new, but tools like these make it even easier.


Starkiller is a framework that, as a Phishing as a Service platform, allows even beginners to carry out highly complex phishing attacks based on HTTP reverse proxies. The goal is to steal a Session Token (also called a session ID or cookie) to bypass two-factor authentication (MFA). Conventional security measures struggle to detect and block this proxy-based approach. They currently advertise a 99.7% success rate! Two-factor authentication in Microsoft 365 can also be circumvented with this method.


What to do?


  • Secure your email inbox as effectively as possible, e.g., with Hornet Security

  • Implement authentication using the highly secure FIDO2 standard, a physically based authentication standard
    e.g., with
    YubiKeys or Swissbit iShield Keys


Links on this topic


https://abnormal.ai/blog/starkiller-phishing-kit


https://cybersecuritynews.com/new-phishing-framework-starkiller-proxies/


https://www.ad-hoc-news.de/boerse/news/ueberblick/starkiller-neue-phishing-plattform-knackt-zwei-faktor-authentifizierung/68597478


https://turingpoint.de/blog/phishing-mit-flexiblem-http-reverse-proxy/