AI Security · Agentic Systems

Securing Agentic AI Without Slowing It Down

A layer-by-layer control map for agentic systems — what actually goes wrong at each layer, how to prevent and detect it, which tools do the work, and where the real trade-off between innovation and control sits.

OWASP LLM Top 10 · MITRE ATLAS · NIST AI RMF ~12 min read
In this piece
  1. Why agentic changes the security problem
  2. What goes wrong, and what covers most of it
  3. Layer 1 — Inputs
  4. Layer 2 — Training
  5. Layer 3 — The agentic system
  6. Layer 4 — Outputs and the feedback loop
  7. The trade-off, and six ways to hold it
  8. References

Why agentic changes the security problem

With a chatbot, the risk was confidentiality. With an agent holding tool access, the risk is authorisation and blast radius.

That sentence is the whole argument, and it is worth being precise about why. A model that answers questions has one failure mode that matters: it says something it should not have said. You control that at the output. An agent that plans over a long horizon, invokes tools, writes to systems and spawns sub-agents has a different failure mode — it does something nobody authorised, assembled from a chain of individually permitted steps.

The CISA and ASD ACSC guidance on careful adoption of agentic AI services frames the system in four layers. The frame is useful because each layer fails differently and is defended differently.

1.  INPUTS
User prompt
Operating context
Config parameters
Audio / video
Documents
Vector / RAG data
Trigger conditions
2.  TRAINING
Training data
Algorithms
Pre-trained LLM
Fine-tuning data
3.  AGENTIC AI SYSTEM
LLM Core — Statistical Model Interprets world state · reasons · plans · decides · takes actions Pursues measurable goals from user directions autonomously
PLANNINGDecomposes goals into multi-step execution plans
Can spawn sub-agents
MEMORYShort-term · long-term
External vector / RAG
Episodic store
TOOLS & DATAAPIs · web · databases
Code executors · files
Sub-agents
ACTION & EXECUTION PRIVILEGESPermissions to interact with tools, users, systems and operating environments · least privilege enforced
CISA / ASD ACSC RISK CATEGORIES
PrivilegeDesign & configBehaviourStructuralAccountability
4.  OUTPUTS
Responses
Text · code
Documents
Data & reports
Actions
Tool invocations
File / DB writes
API calls
Sub-agent spawn
Feedback loop
Tool results
Human-in-loop
Re-plan signal
Autonomous feedback loop — the agent observes results and re-plans without human intervention
The agentic AI system, redrawn from CISA / ASD’s ACSC Careful Adoption of Agentic AI Services (1 May 2026), Figure 1.

What follows takes each layer in turn: the risks that actually materialise, each mapped to OWASP’s LLM Top 10, the relevant MITRE ATLAS technique and a NIST AI RMF subcategory — then the preventive control, the detective control, the configuration that makes both real, and the category of tooling that implements it.

One framing note before the tables. Prevention and detection are not alternatives. Every row below has both, deliberately, because a preventive control you cannot verify is an assertion, and a detective control with nothing preventing the event is an incident-report generator. The configuration column is where the two meet — it is the setting that turns an intention into a control.

What goes wrong, and what covers most of it

The guide names five agentic AI risk categories. They are the organising frame for everything below.

Privilege

Over-broad permissions, scope creep, identity spoofing, and the confused-deputy pattern.

  • Least privilege per task; one cryptographically anchored identity per agent
  • Just-in-time credentials for privileged actions

Design & configuration

Unvetted third-party components, stale start-up authorisation, poor segmentation between agents.

  • Re-evaluate entitlements at every invocation, not once at start-up
  • Segment agent enclaves; keep tool allow lists current

Behaviour

Goal misalignment and specification gaming, deception under evaluation, prompt injection and jailbreaks.

  • Explicit do-not-do rules and guardrails the agent cannot override
  • Adversarial testing and red teaming before production

Structural

Cascading failure across coupled agents, tool squatting, rogue agents, insecure agent-to-agent traffic.

  • Isolation and segmentation to bound the blast radius
  • Mutual TLS on every inter-agent and agent-to-service call

Accountability

Opaque decision chains, sub-agent delegation, hallucination, logs that outpace human review.

  • Unified audit log across all inter-agent interactions
  • Human approval where the cost of error is high

Six control categories cover most of them that cover most of them. The practical question is never “what is the best tool” — it is “what do I already own that does this”.

The practical question is never “what is the best tool” — it is “what do I already own that does this”. Six control categories cover most of the four risks above, and most organisations can cover the first two and the last one with services already inside their cloud subscription.

Model layer — the controls below are the same whichever you run:Claude Anthropic API · Bedrock · VertexOpenAI OpenAI API · Azure OpenAIOpen weights Llama · Mistral, self-hosted

Control — what it doesIf you run AWS If you run Azure / MicrosoftOpen source / stack-neutral
1
Agent identity and secretscovers Privilege · Accountability
IAM Roles Anywhere · Secrets ManagerEntra Workload ID · Key VaultSPIFFE / SPIRE · HashiCorp Vault
2
Policy at the tool boundarycovers Privilege · Design & config
Cedar · Verified PermissionsEntra Conditional Access · OPA on AKSOpen Policy Agent
3
Guardrails on input and outputcovers Behaviour
Bedrock GuardrailsAzure AI Content Safety · Purview DLPLakera · NeMo Guardrails · Presidio
4
Sandboxed tool executioncovers Structural · Design & config
Fargate · Lambda (Firecracker)Container Apps · Container InstancesgVisor · Firecracker · E2B
5
Evals as the release gatecovers Behaviour · Accountability
Bedrock EvaluationsAzure AI Foundry evaluationsPromptfoo · DeepEval · Ragas
6
Trace and immutable audit logcovers Accountability · Structural
CloudTrail → Security LakeAzure Monitor → SentinelLangfuse · OpenTelemetry → Splunk
Start here Rows 1 and 2 — scoped agent identity and a policy check at the tool boundary — bound blast radius structurally, stopping an outcome you never authorised rather than trying to anticipate every misuse. Add row 6 next so you can prove what happened. Rows 3 to 5 can follow the second use case.
On the framework mappings. OWASP identifiers follow the OWASP Top 10 for LLM Applications and ATLAS identifiers the MITRE ATLAS matrix; both evolve, so verify against the current published versions before relying on them in an assessment. The NIST AI RMF subcategory mappings are our own derivation — NIST has not published a crosswalk at this granularity, and a mapping you cannot defend is worse than none. Products named are examples of each control category, not recommendations or an endorsement; verify current capability, licensing and fit before selecting.

1 Inputs

User prompt · operating context · config · audio/video · documents · vector & RAG data · triggers

The ingestion boundary is the cheapest place to stop an attack — and the one most often left open because the content is ‘internal’.

# ·  Cyber risk  ·  OWASP / MITRE ATLAS / NIST AI RMFPrevention  ·  Detection  ·  Configuration  ·  Example tools
1
Direct prompt injection overriding operator instructions
OWASP LLM01 · AML.T0051.000 Direct Prompt Injection
NIST MEASURE 2.7
Prevent · Instruction / data separation at the boundary
Detect · Injection classifier on the prompt stream
Configure · Untrusted content in a channel separate from the system prompt
Example tools · Azure AI Prompt Shields · Bedrock Guardrails · Lakera Guard
2
Indirect injection embedded in documents or RAG content
OWASP LLM01, LLM08 · AML.T0051.001 Indirect Prompt Injection
NIST MEASURE 2.7
Prevent · Strip embedded instructions before indexing
Detect · Provenance diff on every corpus change
Configure · Source allow-list with a trust tier per source
Example tools · Microsoft Purview · MS Presidio · Apache Tika
3
Poisoned or tampered retrieval corpus
OWASP LLM04, LLM08 · AML.T0070 RAG Poisoning
NIST MAP 4.1
Prevent · Signed, versioned corpora; write access restricted
Detect · Index integrity hashing against a baseline
Configure · Immutable snapshots; rollback point per re-index
Example tools · Sigstore / cosign · LakeFS · DVC
4
Regulated data ingress — CUI, PHI, PII, privileged
OWASP LLM02 · AML.T0057 LLM Data Leakage
NIST MEASURE 2.10
Prevent · Redaction and minimisation at the boundary
Detect · DLP alerting on prompt content
Configure · Classification labels enforced pre-processing
Example tools · Microsoft Purview · Google Cloud DLP · Nightfall
5
Malicious uploads and parser exploits
OWASP LLM03 · AML.T0011.000 Unsafe ML Artifacts
NIST MEASURE 2.7
Prevent · Sandbox detonation before the parser sees the file
Detect · AV / EDR plus parser crash telemetry
Configure · File-type allow-list; size and token ceilings
Example tools · ClamAV · VirusTotal · Palo Alto WildFire
6
Forged or unauthenticated triggers
OWASP LLM10 · AML.T0034 Cost Harvesting
NIST MEASURE 2.7
Prevent · Signed webhooks and mTLS on every trigger path
Detect · Alert on any trigger from an unknown identity
Configure · Auto-trigger off by default; per-source rate limits
Example tools · Entra ID / Okta · Kong / Apigee · Istio mTLS
Bottom lineThe dominant risk at this layer is indirect prompt injection through content you ingested on purpose. Prevent it by separating untrusted content from the instruction channel and allow-listing sources with a trust tier. Detect it with an injection classifier on the prompt stream and a provenance diff on every corpus change.

2 Training

Training data · algorithms · pre-trained LLM · fine-tuning data

Most organisations buy this layer rather than build it — which makes vendor terms, version pinning and an AIBOM the real controls.

# ·  Cyber risk  ·  OWASP / MITRE ATLAS / NIST AI RMFPrevention  ·  Detection  ·  Configuration  ·  Example tools
1
Training-data poisoning and implanted backdoors
OWASP LLM04 · AML.T0020 Poison Training Data
NIST MEASURE 2.6
Prevent · Curated sources with provenance review before use
Detect · Backdoor and canary probes on held-out evals
Configure · Dataset version pinning with attestation
Example tools · Cleanlab · Great Expectations · TF Data Validation
2
Model supply-chain compromise — weights, adapters, registries
OWASP LLM03 · AML.T0010.003 ML Supply Chain: Model
NIST GOVERN 6.1
Prevent · Trusted registries only; verify signatures
Detect · Hash mismatch alert on every artifact pull
Configure · Pinned model versions; auto-upgrade blocked
Example tools · Sigstore / cosign · Protect AI ModelScan · HF scanning
3
Fine-tuning leakage of regulated or privileged data
OWASP LLM02 · AML.T0057 LLM Data Leakage
NIST MEASURE 2.10
Prevent · Minimisation and redaction ahead of any tune
Detect · Memorisation and extraction probes post-tune
Configure · Isolated tuning environment; production data excluded
Example tools · MS Presidio · Gretel · Opacus
4
Unverified provenance and licence contamination
OWASP LLM03 · AML.T0010.002 ML Supply Chain: Data
NIST MAP 4.1
Prevent · Licence review gate before dataset ingestion
Detect · Periodic dataset and licence audit
Configure · AIBOM entry mandatory per dataset and adapter
Example tools · CycloneDX AI-BOM · SPDX · FOSSA
5
Model or embedding theft by extraction
OWASP LLM10 · AML.T0024.002 Extract ML Model
NIST MEASURE 2.7
Prevent · Export restriction; keys held in a broker
Detect · Rate and volume anomaly on the inference API
Configure · Per-key quotas and an egress allow-list
Example tools · AWS WAF · Cloudflare · HashiCorp Vault
6
Silent vendor model update invalidating validation
OWASP LLM03 · AML.T0010.001 ML Supply Chain: Software
NIST MANAGE 4.1
Prevent · Contractual notice of material model change
Detect · Eval regression run on every version change
Configure · Version pin plus a staged promotion gate
Example tools · MLflow Registry · Weights & Biases · Bedrock / Azure OpenAI pinning
Bottom lineThe dominant risk at this layer is an unverified model supply chain, because you buy this layer rather than build it. Prevent it by pulling only from trusted registries with signature verification and pinned versions. Detect it with a hash-mismatch alert on every artifact pull and an eval regression run on every version change.

3 The Agentic System

LLM core · planning · memory · tools & data · action and execution privileges

With a chatbot the risk was confidentiality. With an agent holding tool access the risk is authorisation and blast radius.

# ·  Cyber risk  ·  OWASP / MITRE ATLAS / NIST AI RMFPrevention  ·  Detection  ·  Configuration  ·  Example tools
1
Excessive agency — escalation by chaining legitimate tools
OWASP LLM06 · AML.T0053 LLM Plugin Compromise
NIST GOVERN 3.2
Prevent · Tool allow-list with an explicit policy per tool
Detect · Alert on an unexpected tool-call sequence
Configure · Scoped, short-lived credentials; no ambient auth
Example tools · Open Policy Agent · AWS Cedar · scoped MCP servers
2
Goal drift and unbounded autonomous re-planning
OWASP LLM06, LLM10 · AML.T0034 Cost Harvesting
NIST MANAGE 4.1
Prevent · Human approval gate on consequential actions
Detect · Plan-depth and cycle-count monitoring
Configure · Hard caps on steps, depth, time and spend
Example tools · LangGraph recursion limits · LangSmith · Langfuse
3
Memory poisoning persisting across sessions
OWASP LLM08 · AML.T0070 RAG Poisoning
NIST MEASURE 2.7
Prevent · No memory writes originating from untrusted content
Detect · Provenance-tag audit on every memory read
Configure · TTL on long-term memory; signed writes only
Example tools · Qdrant / Pinecone namespaces & ACLs · Redis ACL · Sigstore
4
Uncontrolled sub-agent spawning
OWASP LLM06, LLM10 · AML.T0029 Denial of ML Service
NIST MANAGE 2.4
Prevent · Spawning requires an explicit grant
Detect · Live inventory of active agent identities
Configure · Max concurrent sub-agents; one identity per agent
Example tools · SPIFFE / SPIRE · Entra Workload ID · IAM Roles Anywhere
5
Tool and API abuse — SSRF, code execution, egress
OWASP LLM05 · AML.T0055 Unsecured Credentials
NIST MEASURE 2.7
Prevent · Sandboxed executor with a read-only filesystem
Detect · Egress and syscall monitoring on the executor
Configure · Network egress allow-list scoped per tool
Example tools · gVisor · Firecracker · E2B
6
Non-determinism defeating repeatable assurance
OWASP LLM09 · AML.T0031 Erode ML Model Integrity
NIST MEASURE 2.3
Prevent · Schema-constrained outputs at the tool boundary
Detect · Continuous eval harness with pass thresholds
Configure · Signed action log attributing each step to a plan
Example tools · Promptfoo · DeepEval · Ragas
Bottom lineThe dominant risk at this layer is excessive agency — a chain of individually permitted tool calls producing an outcome nobody authorised. Prevent it with least-privilege scoped credentials per tool and a human gate on consequential actions. Detect it by alerting on unexpected tool-call sequences and monitoring plan depth and cycle count.

4 Outputs and the Feedback Loop

Responses · actions · tool results · human-in-loop · re-plan signal

The governance question is no longer whether a human was in the loop — it is whether anyone can demonstrate judgment was exercised.

# ·  Cyber risk  ·  OWASP / MITRE ATLAS / NIST AI RMFPrevention  ·  Detection  ·  Configuration  ·  Example tools
1
Fabricated content reaching a customer, court or regulator
OWASP LLM09 · AML.T0062 Discover LLM Hallucinations
NIST MEASURE 2.3
Prevent · Mandatory human review before external release
Detect · Citation and fact verification step, logged
Configure · Release gate keyed to a named reviewer
Example tools · Ragas · TruLens · Galileo
2
Sensitive data exfiltration through the response channel
OWASP LLM02 · AML.T0057 LLM Data Leakage
NIST MEASURE 2.10
Prevent · Output redaction before the response leaves
Detect · Egress DLP on the response channel
Configure · Classification-driven egress rules
Example tools · Purview DLP · Nightfall · MS Presidio
3
Unauthorised or irreversible actions — writes, deletions, payments
OWASP LLM06 · AML.T0053 LLM Plugin Compromise
NIST MANAGE 2.4
Prevent · Explicit approval required for irreversible operations
Detect · Alert on any out-of-policy write attempt
Configure · Dry-run by default; idempotency keys on writes
Example tools · OPA / Cedar · ServiceNow approvals · Temporal compensations
4
Insecure generated code promoted to production
OWASP LLM05 · AML.T0011 User Execution
NIST MEASURE 2.7
Prevent · Peer review, the same as any other code
Detect · SAST and SCA in the delivery pipeline
Configure · Secure SDLC gate regardless of code origin
Example tools · Semgrep · Snyk · GitHub CodeQL
5
Feedback loop amplifying an error with no checkpoint
OWASP LLM10 · AML.T0034 Cost Harvesting
NIST MANAGE 4.1
Prevent · Human checkpoint before the loop repeats
Detect · Cycle-count and repeat-failure alerting
Configure · Hard cap on autonomous cycles per task
Example tools · LangGraph max iterations · Langfuse · AgentOps
6
Attribution gap — no evidence that judgment was exercised
OWASP LLM09 · no direct ATLAS technique — assurance gap
NIST MEASURE 2.8
Prevent · Reviewer identity captured against each artifact
Detect · Periodic audit sampling of AI-assisted work
Configure · Immutable per-transaction audit trail
Example tools · Splunk · Microsoft Sentinel · CloudTrail Lake
Bottom lineThe dominant risk at this layer is fabricated output reaching a third party with no evidence anyone reviewed it. Prevent it with a release gate keyed to a named reviewer and no irreversible action without approval. Detect it with a logged citation-verification step and periodic audit sampling of AI-assisted work.

The trade-off, and six ways to hold it

The trade-off is real. It is just not the one most organisations argue about.

The argument is usually framed as speed versus safety: engineering wants to ship, security wants to gate, and the outcome is a committee. That framing loses every time, because it makes security a tax on velocity rather than a precondition for it.

The real distinction is between controls you can evidence and controls you merely assert. An asserted control — a policy, a review board, a signed attestation — costs almost nothing to create and buys nothing durable, because every new use case reopens the same conversation. An evidenced control — a scoped credential, an action log, an eval that passes in CI — costs something once, then makes the second and third use case cheap.

Six practical positions that follow from that.

1

Tier by blast radius, not by model

A read-only research agent and one that can move money are not the same risk. Gate on what the agent can do to the world, not on which vendor supplies the weights.

2

Make the eval the gate, not the committee

A non-deterministic system cannot be assured by a review board and a screenshot. Pass thresholds in CI let you ship weekly; a monthly committee does not.

3

Scope the credential, not the conversation

Least privilege per tool, short-lived, one identity per agent. Draw the box tightly and the agent can explore freely inside it — that is where the speed comes from.

4

Default to reversible

Dry-run, idempotency keys, compensating transactions. Reversibility is what buys autonomy: an action you can undo does not need a human standing over it.

5

Instrument before you widen

An action log attributing each step to a plan and an identity is the artifact that lets you say yes to the next use case. Without it every expansion restarts the argument.

6

Time-box the pilot, not the ambition

A 90-day bounded pilot with a kill switch and a named owner beats an 18-month governance programme that ships nothing and learns nothing.

The one to act on first: point 3. Scoping the credential rather than policing the conversation is what gives engineering room to move while keeping blast radius bounded. Every other control on this page gets easier once each agent and sub-agent holds its own short-lived, tightly scoped identity.

Where to start

Start with the layer that carries your blast radius. For most organisations that is Layer 3 — action and execution privileges — not Layer 1, even though Layer 1 is where the attack enters. The reason is asymmetry: a prompt injection reaching an agent with read-only scope is an annoyance; the same injection reaching an agent with write access to a production system is an incident. Bound the privilege first, then work outward to the ingestion boundary and the output gate.

Two artifacts are worth building before anything else, because everything else depends on them. An inventory of what agents exist, what tools each can invoke and what data each can reach — you cannot assess a population you have not defined. And an action log attributing each step to a plan and an identity — without it you cannot scope an incident after the fact, and you cannot answer the question a client or regulator will eventually ask: how was AI used here, who reviewed it, and when?

References

Primary guidance

Careful Adoption of Agentic AI Services — ASD’s ACSC, CISA, NSA, the Canadian Centre for Cyber Security, NCSC-NZ and NCSC-UK, 30 April 2026. The first coordinated Five Eyes guidance on agentic AI; source of the five risk categories and the system diagram. cisa.gov · full PDF

Industry research

Cloud Security Alliance, AI Safety Initiative — research notes on the joint guidance and the 2026 agentic identity survey: 82% of organisations have found unknown AI agents in their environment, 65% had an agent security incident in the past twelve months, and 21% have a formal agent decommissioning process. labs.cloudsecurityalliance.org

Frameworks used for mapping

OWASP Top 10 for LLM Applications — source of the OWASP identifiers on every risk row. The guidance also cites OWASP Top 10 for Agentic Applications (2026), worth reviewing alongside it.

MITRE ATLAS™ — Adversarial Threat Landscape for AI Systems; source of the AML.T identifiers, and named in the guidance as a recommended threat-modelling taxonomy.

NIST AI Risk Management Framework — source of the GOVERN / MAP / MEASURE / MANAGE subcategory references. Those mappings are our derivation, not an official crosswalk.

Also cited in the guidance

NIST SP 800-207 Zero Trust Architecture · CISA 2025 Minimum Elements for a Software Bill of Materials · CISA AI Cybersecurity Collaboration Playbook · NCSC-UK Guidelines for Secure AI System Development · MIT STAMP / STPA-Sec materials

Verification note. OWASP and MITRE ATLAS identifiers change between published versions — check both against the current release before using them in an assessment. The NIST AI RMF subcategory mappings are our derivation; NIST has not published a crosswalk at this granularity. Products named throughout are examples of a control category, not recommendations or an endorsement.

Diagram redrawn from Figure 1 of the joint guidance. © Commonwealth of Australia 2026, licensed CC BY 4.0.