LLM Prompt Injection | Testing & Defence

Understand and test for prompt injection, the most critical vulnerability in LLM applications.

What is LLM Prompt Injection?

LLM prompt injection is a class of attack where crafted input manipulates a language model into ignoring its instructions. It covers both direct injection through user input and indirect injection through poisoned content.

Why it matters

It tops the OWASP LLM Top 10 for good reason: a successful injection can leak your system prompt and data, bypass safety controls, and abuse any tools the model can reach. Every LLM feature is exposed to some degree.

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How Solusec tests it

We test your application for direct and indirect prompt injection, measure the real impact against your guardrails and data, and give you layered mitigations that reduce the risk to an acceptable level.

AI testing, led by a human

Solusec is one of the first firms worldwide accredited under CREST's AI-Enabled Penetration Testing standard, so our use of AI is independently assured: responsible, transparent and always human-led. You get faster, broader testing, your data stays out of public AI tools, and every finding is validated by a qualified tester. Read about the accreditation.

What you get

You get a clear, prioritised report mapped to business risk, a walkthrough of every finding with practical fixes your developers can action, and a free retest once you have remediated. No scanner dump, no jargon, no sales team: you deal directly with the tester.

Common questions

Is prompt injection really that serious?

Yes. It is the top LLM risk because it can undermine every other control in your AI system.

Do you test both direct and indirect injection?

Yes, both, because defending one without the other leaves a wide gap.

How quickly can testing start?

After a short, free scoping call we give a fixed price and a start date, often within days.

Is your AI use safe and independently assured?

Yes. Solusec holds CREST's AI-Enabled Penetration Testing accreditation, which independently assures that our AI use is responsible, secure and human-led.

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