Seasoning email threats with hidden text salting

Cisco Talos details a rise in phishing emails using “hidden text salting” to evade detection by inserting invisible or visually hidden content via CSS (e.g., display/width/overflow), zero-width characters, language poisoning to mislead headers, and obfuscated base64 in HTML smuggling; the report explains how these tactics undermine brand extraction, language detection, and attachment decoding, and recommends advanced filtering that flags suspicious CSS/HTML usage and augments text-based parsing with visual features, supported by AI-driven email security.