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AI-900 Practice Question: Describe features of generative AI workloads on Azure

What is 'prompt injection' and why is it a security concern for AI applications?

⚠ Common exam trap

Test-takers frequently confuse prompt injection with benign prompt engineering or testing activities, failing to recognize that the key distinction is malicious intent to override system instructions rather than legitimate modification or evaluation of prompts.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Malicious input that overrides an AI system's instructions to hijack its behaviour

Prompt injection is a security vulnerability where an attacker crafts input that overrides or bypasses the system-level instructions (system prompt) of an AI model, causing it to behave in unintended ways. This is a critical concern because generative AI models, especially large language models (LLMs), are designed to follow instructions in the prompt, and a malicious user can inject commands that hijack the model's behavior, potentially exposing sensitive data, generating harmful content, or performing unauthorized actions. In Azure AI services, this risk is mitigated through content filtering, input validation, and the use of metaprompt protections.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • When developers inject test prompts to evaluate model performance

    Why it's wrong here

    Running benign test prompts to evaluate a model is a standard QA and red-teaming practice, not a prompt-injection attack as the term is used in security. Prompt injection specifically refers to an adversarial, untrusted input that is crafted to override the model's system instructions and alter its behavior in a harmful way. The intention and the threat model are different: an evaluator controls the test to observe performance, whereas an attacker controls the prompt to break the application's intended policy.

  • Malicious input that overrides an AI system's instructions to hijack its behaviour

    Why this is correct

    Prompt injection is the deliberate insertion of malicious instructions into user-supplied or retrieved content that the model processes as data. Because an LLM treats the system prompt and incoming text as the same token stream, a crafted phrase can override the original instructions and force the model to ignore guardrails, reveal sensitive information, or take unintended actions. This is the canonical exploitation of instruction-following behavior and is one of the most serious security risks for LLM-based applications.

  • The process of adding new prompts to expand a model's capability

    Why it's wrong here

    Adding new prompts to expand what a model can do is prompt engineering or fine-tuning, not an attack. In prompt injection, the attacker does not enhance the model — instead, they exploit the model's existing instruction-following capability to divert it from its intended behavior. The malicious 'new prompt' is not a feature; it is an unauthorized command that the model mistakenly treats with the same authority as its original system instructions.

  • Accidentally sending the wrong prompt to the model due to a software bug

    Why it's wrong here

    Accidentally sending the wrong prompt because of a software bug is an implementation defect, not a security exploit. Prompt injection is a deliberate adversarial action where the attacker crafts input specifically to override the system's instructions, not a coding mistake in how prompts are routed or dispatched. The distinction matters because injection attacks can occur even when the software is perfectly functional — the vulnerability lies in the model's tendency to obey instructions embedded in untrusted text.

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Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

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