Understanding LLM Prompt Injection Attacks

Prompt injection is one of the most critical vulnerabilities in LLM-powered applications. This article explores the taxonomy of prompt injection attacks, real-world examples, and practical defense strategies.

What is Prompt Injection?

Prompt injection occurs when an attacker crafts input that manipulates the behavior of an LLM beyond its intended purpose. This can lead to data exfiltration, unauthorized actions, or bypassing safety guardrails.

Types of Prompt Injection

• Direct Injection: Overriding system prompts with adversarial user input
• Indirect Injection: Embedding malicious instructions in external data sources
• Stored Injection: Persisting malicious prompts that trigger on future interactions

Defense Strategies

Effective defense requires a layered approach: input validation, output filtering, sandboxing, and continuous monitoring.