Token Smuggling: Bypassing Filters with Non-Standard Encodings
IT InstaTunnel Team Published by our engineering team Token Smuggling: Bypassing Filters with Non-Standard Encodings 🕵️♂️🔠Introduction: The “Lost in Translation” Vulnerability In the rapidly evolving world of Large Language Model (LLM) security, a silent arms race is being fought not with complex code injections, but with the fundamental building blocks of language itself. Security filters—the guardrails designed to catch malicious inputs—are often like bouncers checking ID cards at the door. They look for specific “banned” faces: words like DROP TABLE , system_prompt , or explicit hate speech. Token Smuggling acts as a master of disguise. It allows attackers to slip these banned concepts past the bouncers by altering their appearance just enough to be unrecognizable to the filter, yet perfectly legible to the LLM inside. This technique exploits a critical discrepancy: the difference between how a simple text-matching filter “reads” a string and how an LLM’s...