Agent Series (13): Agent Security and Defense — Prompt Injection, Tool Abuse, and Data Leakage (opens in new tab)

An Agent's Attack Surface Is Bigger Than You Think A plain LLM application has one attack surface: user input → LLM output. Add tools to the mix, and it triples: User input ──→ [LLM] ──→ Tool call args ──→ [Tool exec] ──→ Tool result ──→ [LLM] ──→ Output ↑ ↑ ↑ Prompt injection Tool param injection Indirect injection / leakage Every arrow is a potential attack vector. This article covers three main attack chains and the defenses that correspond to each. Attack Types at a Glance 1. Prompt Injec...