Prompt injection: complete definition in AI for SMEs

A prompt injection is an attack that inserts malicious instructions into an AI's conversation to hijack its behavior: disclosing internal information, executing unauthorized actions, ignoring system prompt rules, or generating harmful content. It can be direct (the attacker writes to the AI) or indirect (the content of a webpage, PDF or email read by the AI contains the hidden instruction).

What it changes for an SME

Prompt injections are the number one security risk for chatbots and agents connected to your data:

• a visitor manipulates the website chatbot into revealing internal data;
• a received email contains a hidden instruction that your support agent unknowingly executes;
• an attached document pushes the AI to bypass the business rules defined in the system prompt.

How to protect yourself

Never give the AI more rights than necessary. Isolate sensitive data from the public interface. Have humans validate high-stakes actions. Regularly test the system's resistance to injections (security audit). In fractional AI leadership, we integrate these tests into every agent deployment.