ASCII smuggling crosses over from AI prompt injection to phishing evasion

Microsoft observed a large-scale finance-themed phishing campaign that used invisible Unicode tag characters (the Unicode Tags block U+E0000–U+E007F, especially U+E0020) to split high-signal lure words (e.g., "funding" -> "fun⟨U+E0020⟩ding") and evade keyword/token-based detections. The technique, adapted from AI prompt-injection research ('ASCII smuggling'), produced weekday-focused spikes beginning 9 Feb 2026 and persisted through mid-May 2026 with millions of messages per day, leveraged disposable finance-branded sender domains relayed through the ActiveCampaign platform (notably traffic from 173.236.20.0/24), and yielded concrete detection and normalization guidance plus hunting queries and IOCs.