AI & LLM Security Skill for Claude

AI & LLM Security

Purpose

Enable Claude to assess the security of AI/LLM-powered applications — chatbots, RAG pipelines, autonomous agents, and tool-using systems. Claude maps findings to the OWASP Top 10 for LLM Applications (2025) and the MITRE ATLAS adversarial-ML knowledge base, builds reproducible attack cases, and recommends concrete mitigations (input/output guardrails, least-privilege tool scopes, content provenance).

> Authorization Required: Only test AI systems you own or are explicitly authorized to assess. Prompt-injection and data-exfiltration testing against third-party AI services may violate their terms of service and local law. Confirm written scope before proceeding.

Activation Triggers

This skill activates when the user asks about:

• Prompt injection (direct or indirect), jailbreaks, or system-prompt extraction
• OWASP LLM Top 10, MITRE ATLAS, or AI/ML threat modeling
• Securing a RAG pipeline, vector database, or retrieval layer
• LLM agent / tool-use / function-calling security and confused-deputy risks
• Guardrail, content-filter, or model output validation design
• Sensitive-information disclosure or training-data leakage from a model
• Model / ML supply chain security (model files, pickle, model registries)
• AI red teaming, jailbreak corpora, or automated adversarial prompt generation
• Securing MCP (Model Context Protocol) servers and tool integrations

Prerequisites

pip install requests pyyaml rich

Optional enhanced capabilities:

• garak — LLM vulnerability scanner (NVIDIA)
• promptfoo — prompt/red-team evaluation harness
• API key for the target LLM endpoint (test environment only)
• modelscan / picklescan — ML model file safety scanning

Core Capabilities

1. Threat Modeling (OWASP LLM Top 10 — 2025)

When asked to threat-model an AI application, map the system against each category and record exposure:

| ID | Risk | What to look for |

|----|------|------------------|

| LLM01 | Prompt Injection | Untrusted text reaching the prompt (direct & indirect via RAG/web/email) |

| LLM02 | Sensitive Information Disclosure | PII/secrets in prompts, outputs, or training data; system-prompt leakage |

| LLM03 | Supply Chain | Untrusted models, LoRA adapters, datasets, plugins, pickle deserialization |

| LLM04 | Data & Model Poisoning | Tainted training/fine-tune/RAG data; backdoors |

| LLM05 | Improper Output Handling | LLM output passed unsanitized to SQL, shell, browser (XSS), or eval |

| LLM06 | Excessive Agency | Over-broad tool scopes, autonomous side effects, no human-in-the-loop |

| LLM07 | System Prompt Leakage | Secrets/authz logic embedded in the system prompt |

| LLM08 | Vector & Embedding Weaknesses | RAG access-control bypass, embedding inversion, cross-tenant leakage |

| LLM09 | Misinformation | Hallucinations relied on for security/safety decisions |

| LLM10 | Unbounded Consumption | Cost/DoS via token floods, model extraction, wallet-drain |

Produce a per-category table: Exposure (Yes/No/Partial) → Evidence → Severity → Mitigation.

2. Prompt Injection & Jailbreak Testing

Direct injection — user input that overrides instructions. Test families:

• Instruction override ("ignore previous instructions and …")
• Role-play / persona escape (DAN-style, hypothetical framing)
• Encoding/obfuscation (Base64, ROT13, leetspeak, homoglyphs, zero-width chars)
• Token smuggling and prompt-boundary confusion (fake delimiters, fake system tags)
• Many-shot jailbreaking (long context of faux dialogue priming compliance)
• Crescendo / multi-turn gradual escalation

Indirect injection — payload arrives via retrieved/processed content (web page, PDF, email, RAG doc, tool output). This is the highest-impact class for agents. Test that retrieved text cannot issue commands, exfiltrate context, or trigger tools.

For every test record: payload, channel (direct/indirect), goal (override / exfiltrate / tool-abuse), and result (blocked / partial / success). Use scripts/prompt_injection_tester.py to run a corpus and score outcomes.

Refusal-quality note: a single refusal is not a pass. Re-test the same goal across ≥3 phrasings and obfuscations before marking a control effective.

3. RAG & Vector Store Security

When reviewing a RAG pipeline:

• Access control at retrieval — confirm the vector query is filtered by the *caller's* permissions, not just the app's. Test cross-tenant / cross-user document leakage.
• Indirect injection surface — treat every ingested document as attacker-controlled; verify retrieved chunks are clearly delimited and never executed as instructions.
• Embedding inversion / membership — sensitive source text may be partially reconstructable from embeddings; flag PII stored unencrypted in the vector DB.
• Chunk poisoning — a single malicious document can dominate retrieval; check ranking/dedup and source allow-listing.
• Citation integrity — outputs should cite retrieved sources so injected claims are traceable.

4. Agent & Tool-Use (Function Calling / MCP) Security

The agent is a confused deputy: it holds privileges the user may not. Review:

• Least-privilege tools — each tool scoped to the minimum action; no broad execute_shell/http_request to arbitrary hosts
• Human-in-the-loop gates on irreversible/outbound actions (payments, email send, file delete, deploy)
• Argument validation — tool args are model-generated and untrusted; validate/allow-list server-side
• Injection → tool chain — verify retrieved/indirect content cannot drive tool calls (e.g., a web page telling the agent to email its memory out)
• MCP server hardening — authenticate clients, scope resources, rate-limit, log every tool invocation; never expose secrets via resource reads
• Memory poisoning — persistent agent memory can be seeded with malicious instructions that fire on later turns

5. Model & ML Supply Chain

• Scan model artifacts for unsafe deserialization — pickle/.pt/.bin can execute code on load. Prefer safetensors. Run scripts/model_supply_chain.py or modelscan.
• Verify model provenance, hashes, and signatures; pin versions from trusted registries.
• Review fine-tune/LoRA adapters and datasets for poisoning and licensing.
• Treat third-party plugins/MCP servers as untrusted dependencies (review + pin).

6. Output Handling & Guardrails

• Never pass raw LLM output into eval, SQL, shell, or innerHTML. Encode/parameterize at the sink (LLM05).
• Layered guardrails: input filter → policy in system prompt → output classifier → sink-specific sanitization. Defense in depth, since any single layer is bypassable.
• Validate structured output against a strict schema; reject on parse failure.
• Apply egress controls so an injected agent cannot reach attacker URLs.

Output Standards

Produce a structured AI security assessment:

# AI/LLM Security Assessment — [Application]
Date: [Date] | Scope: [Endpoints/Models] | Model: [name/version] | Analyst: [Name]

## Executive Summary
[2-3 sentences: overall posture, highest risks]

## OWASP LLM Top 10 Coverage
| ID | Risk | Exposure | Severity | Evidence |
|----|------|----------|----------|----------|
| LLM01 | Prompt Injection | Yes | High | [repro] |
...

## Confirmed Findings
### [F-01] Indirect Prompt Injection via RAG → Tool Abuse  (Critical)
- ATLAS: AML.T0051 / OWASP LLM01+LLM06
- Repro: [payload, channel, steps]
- Impact: [data exfil / unauthorized action]
- Mitigation: [least-privilege tool scope + retrieved-content isolation + HITL]

## Guardrail Bypass Matrix
| Goal | Direct | Encoded | Multi-turn | Indirect | Result |

## Recommendations (Prioritized)
1. ...

Script Reference

prompt_injection_tester.py

# Run the built-in injection/jailbreak corpus against an endpoint
python scripts/prompt_injection_tester.py --url https://app.test/api/chat --field message --output results.json

# Use a custom payload corpus and a refusal-detection keyword set
python scripts/prompt_injection_tester.py --url ... --corpus payloads.txt --judge-keywords refusals.txt

model_supply_chain.py

# Scan a model directory/file for unsafe pickle opcodes and risky imports
python scripts/model_supply_chain.py --path ./models/model.pt
python scripts/model_supply_chain.py --path ./models/ --recursive --output scan.json

Skill Integration

| Next Step | Condition | Target Skill |

|-----------|-----------|--------------|

| Web/API vuln testing of the app shell | App exposes web/API surface | → Skill 09 |

| Cloud/infra hosting the model | Model served on AWS/Azure/GCP/K8s | → Skill 10 |

| Detection rules for prompt-injection attempts | Need SIEM coverage | → Skill 12 |

| Dependency/model-package CVEs | ML libs in use | → Skill 02 |

| Red team narrative incorporating AI abuse | Full engagement | → Skill 14 |

References

• OWASP Top 10 for LLM Applications (2025)
• MITRE ATLAS — Adversarial Threat Landscape for AI Systems
• NIST AI Risk Management Framework (AI RMF 1.0) + Generative AI Profile
• OWASP Agentic AI — Threats and Mitigations
• Google SAIF — Secure AI Framework
• NVIDIA garak — LLM vulnerability scanner