Phishers hijack AI evasion tactics to bypass email filters
Microsoft researchers identified a massive phishing campaign that repurposed 'ASCII smuggling,' a technique previously associated with AI prompt injection, to evade email security filters. By inserting invisible Unicode tag characters into financial keywords like 'funding,' attackers prevented keyword and machine learning detectors from recognizing malicious content. The campaign, which peaked at over 2.37 million messages daily in late February 2026, utilized the ActiveCampaign marketing platform and targeted small business loan applicants. Microsoft advises defenders to normalize invisible characters in their filtering pipelines to close this detection gap.
