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

Generative AI is enabling threat actors to craft phishing emails that are grammatically flawless, highly personalized, and unique at scale, stripping away the behavioral 'tells' — poor grammar, repetitive phrasing, unusual formatting — that traditional detection systems relied upon to flag malicious messages. This represents a fundamental shift in the threat landscape: defenses built around recognizing human error in attacker communications are now structurally obsolete. Organizations that have not updated their email security strategies to incorporate multi-signal detection (including content analysis, sender reputation, link analysis, and contextual awareness) are increasingly exposed. The human element is also at greater risk, as even security-aware employees may struggle to distinguish AI-polished phishing from legitimate correspondence.