Title: Discussion 3 — Picking Your Leg of the Lethal Trifecta
Course: AIINFRA 302: AI Security, Guardrails & Governance > Section: Week 03 — Direct and Indirect Prompt Injection Attacks

💬 Discussion 3 — Picking Your Leg of the Lethal Trifecta (20 pts)

Imagine a customer-support email agent: it reads incoming customer emails (untrusted content), has access to the customer database and past ticket history (private data), and can send emails and update tickets on its own (external communication) — all three legs of Willison's lethal trifecta. Using the lethal-trifecta checklist from this week's lecture: which single leg would you remove to make this agent safe against indirect injection, and what functionality would that cost you? Be specific — name the leg, describe the concrete change you'd make to the system architecture, and be honest about the tradeoff (e.g., what the agent could no longer do for customers or for your support team). Post your initial response (150+ words) by the midweek deadline, then respond to at least two classmates — ideally classmates who picked a different leg than you — and engage with whether their tradeoff is actually acceptable in practice.