InjectionGuard — Multilingual Prompt Injection Defence

InjectionGuard is a security research tool that detects and blocks indirect prompt injection attacks against LLM-powered applications — a threat class where hidden instructions embedded in emails or documents hijack an AI assistant's behaviour.

Built as a 3-layer guardrail: (1) a Unicode/HTML sanitiser that strips invisible characters and hidden tags, (2) a heuristic pattern engine with 30+ regex rules covering both English and Arabic injection phrases, and (3) a spotlighting layer that wraps untrusted content so the model treats it as data, not commands.

Key result: 95% detection accuracy with 100% precision and zero false positives across a 20-payload benchmark spanning English and Arabic. The bilingual coverage addresses a real gap — most existing guardrails are English-only.

Grounded in research from Greshake et al. (ACM CCS 2023) and Microsoft's Spotlighting work (2024).