AI CTF / Challenge Writeups

Hands-on writeups from AI security capture-the-flag challenges — prompt injection, jailbreaks, and the defenses that try to stop them. Each writeup documents what worked, why it worked at the model level, and what the failure teaches defenders building real LLM applications.

I write these from the builder's side of the table: I build and harden AI agents, and breaking guarded models is how I pressure-test the guardrails I put on my own. These are the attacks I want my systems to survive.

Challenges

Challenge	Focus	Status
Gandalf (Lakera)	Prompt injection across 7 escalating defense layers	Complete (L1–L7)

Why these exist

Prompt injection is the #1 risk on the OWASP Top 10 for LLM Applications. Every technique in these writeups maps to a real vulnerability class in production AI systems — and every level Gandalf loses is a lesson in why "just tell the model not to" is not a security control.

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Writeups by rpriven. Educational and defensive use only — all challenges are public, sanctioned security games.