Generative AI Is Erasing Behavioral Tells, Weakening Behavior-Only Detection, Proofpoint Reports

Generative AI is altering the characteristics of malicious emails, making them appear more fluent and personalized. This change is causing the behavioral signals that email filters have traditionally relied on to become less effective. Malicious emails are now less likely to be identified by their wording, pretexts, and templates. As a result, the traditional methods of detecting malicious emails are weakening. Proofpoint has highlighted this shift with several examples at its Protect 2026 conference. The evolution of malicious emails is making it more challenging for email filters to detect them based on behavior alone.