AI Spam Filters Defeated by Decades-Old Text Salting
New AI-powered defenses can be vulnerable to old, low-tech evasion tactics.
Old trick, new targets
Text salting is a technique where spammers insert invisible or barely visible characters into messages to evade keyword-based filters. The method dates back decades to early email spam wars.
Some LLM-powered email filters are now proving susceptible to these same techniques. The AI systems, trained to understand natural language, can be fooled by character insertions that would trip traditional pattern matching.
Why AI filters miss it
Large language models are designed to be robust to minor text variations, a feature that helps them handle typos and informal writing. That same flexibility becomes a weakness when spammers deliberately introduce noise.
The finding suggests that combining multiple detection approaches — statistical, pattern-based, and AI-powered — may be more resilient than relying on any single method.