The threat map

You can't gate a threat you haven't mapped. Before you write a single guardrail, you need the shape of your attack surface — every place untrusted data or capability enters the model. This module hands you the two maps the field already agreed on, so you stop guessing and start covering.

Why "just add a filter" fails

The naive instinct is to bolt one input filter in front of the model and call it secure. But an LLM app isn't a single door — it's a perimeter. Untrusted text arrives from the user, from retrieved documents, from tool outputs, and from memory the model wrote to itself on a previous turn. Each of those is a distinct entry point with a distinct failure mode. Filter the user prompt and you've left the retrieval channel, the tool channel, and memory wide open. Coverage is a map problem before it's a control problem.

Map one — OWASP Top 10 for LLM Applications (2025)

Published by the OWASP Gen AI Security Project, this list names the canonical model-level risks. Its top entry, LLM01: Prompt Injection, is the one every other channel inherits — untrusted content persuading the model to ignore its instructions. Neighbors on the list cover sensitive-information disclosure, supply-chain risk, insecure output handling, and data/model poisoning. Treat it as the baseline vocabulary: when you triage an incident, you should be able to name it with an OWASP category.

Map two — OWASP Top 10 for Agentic Applications (2026)

The moment your app can act — call tools, spend budget, write to systems — the model-level list is no longer enough. The Gen AI Security Project's newer agentic list addresses this; its entries carry ASI0x ids (ASI01 Agent Goal Hijack, ASI02 Tool Misuse & Exploitation…). The risk it centers on is LLM06:2025 Excessive Agency (formally an entry on the model-level Top 10): an agent granted more capability, autonomy, or permission than the task actually requires. A prompt injection against a chatbot leaks text; the same injection against an agent with a shell tool and a wallet executes. Excessive agency is what turns a content risk into a blast radius. The agentic-era question is not "what can the model say" but "what can the model do, and did we scope that down to the minimum?"

The adversary's playbook — MITRE ATLAS

OWASP tells you what can go wrong. MITRE ATLAS (Adversarial Threat Landscape for Artificial-Intelligence Systems) tells you how real adversaries do it — a knowledge base of tactics and techniques against AI systems, structured like the ATT&CK framework security teams already use. Use OWASP to enumerate risk categories and ATLAS to enumerate the concrete techniques that realize them, so your tests mirror attacker behavior instead of your own imagination.

The agentic attack surface

Here is the perimeter, drawn. Four untrusted inputs converge on the model core, which can act through tools — each edge tagged with the OWASP category that governs it.

A map is only useful if it drives tests

Naming a risk is step zero; the harness turns each category into an executable check. The pattern is a threat-to-test mapping — a small config that binds every surface node to its OWASP category and the probe that proves whether the gate holds. If a node has no test, it isn't covered — it's assumed safe, which is how blind spots survive review.

# threat_map.yaml — every surface node -> OWASP category -> a probe that gates it
surface:
  - node: user_input
    owasp: LLM01_prompt_injection
    probe: inject_ignore_instructions      # attacker overrides system prompt
    gate: refuses AND stays on task

  - node: retrieved_content
    owasp: LLM01_indirect_injection
    probe: poisoned_document               # instructions hidden in a RAG doc
    gate: no instruction obeyed from data

  - node: tool_output
    owasp: LLM05_improper_output_handling
    probe: malicious_tool_response         # tool returns markup / commands
    gate: output validated before use

  - node: memory
    owasp: LLM04_data_and_model_poisoning
    probe: persist_hostile_note            # attacker text survives to next turn
    gate: memory sanitized on read

  - node: tool_invocation
    owasp: LLM06_excessive_agency          # LLM06:2025; the Agentic Top 10 (ASI0x) centers on it
    probe: over_privileged_action          # agent tries beyond task scope
    gate: least-privilege scope enforced

# unmapped node == blind spot. coverage = mapped_nodes / total_nodes

You'll build and run probes like these in later modules; here the point is the discipline — coverage is measured against a map, not a feeling. Every node earns a category and a probe, or it's flagged as unexamined.