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AI Security Reference ArchitecturesTrack A: Model access

A4 In-Boundary Inference

In-boundary inference keeps prompts and outputs inside your cloud provider's compliance boundary or your own cluster, either through a managed service over private networking or with open-weight models on your own GPUs. Both work today. The managed path is buy plus glue, mostly logging and region pinning. Self-hosting is mostly custom work on mature open source, and GPU cost dominates.

Buy + glue Owner: Platform eng + cloud team Control: High to Highest Stand up: 2 wks to 4 mos

Who it fits: Regulated, residency-bound or IP-sensitive orgs. Two variants: a managed cloud AI service, or open-weight models you run.

Frameworks: AWS GenAI scope 3 and 4AWS agentic scope No agencyOWASP LLM02 Sensitive Information Disclosure, LLM04 Supply Chain, LLM05 Data and Model Poisoning

Last reviewed October 2026. Vendor tiers and features change often. Spot something out of date? Tell us.

FlowsPrompt / responseTool callIdentity / credentialTelemetryUnsafe pathBlocked
BoundariesYour boundaryThird party
2 variants
A4.1

Managed cloud AI

The cloud runs the model inside its compliance boundary. You get IAM identity and private networking.
Your VPC, private subnetsCloud AI service123456ACTOREmployeesvia SSOIDENTITYWorkload identityIAM role, no static keysKEEPWORKLOADWorkload (EKS / ECS)RAG app, doc processorWORKLOADVector DB / dataPHI stays in regionCONTROLPrivateLink endpointno internet egressKEEPTELEMETRYCloudTrail + logsinvocations to SIEMSIMPLIFYCONTROLProvider guardrailsBedrock Guardrails etc.DEFERMODELManaged modelsBedrock, Foundry, Agent Platform

Data flow

  1. 1Users sign in to an internal app.
  2. 2The workload gets short-lived credentials from its IAM role. No API keys exist.
  3. 3Retrieval pulls sensitive context from data stores inside the VPC.
  4. 4Model calls go through a PrivateLink endpoint, never the public internet. In-region inference profiles keep data in region.
  5. 5Provider guardrails filter each invocation inside the cloud's compliance boundary (BAA, FedRAMP, region).
  6. 6Invocation logging is off by default and misses Bedrock's newer mantle endpoint, so turn it on, and keep apps on bedrock-runtime or log in the app. With CloudTrail, both land in your account and stream to the SIEM.

Managed cloud AI: build or buy

Buy + glue

What you can buy for each box in the diagram, the open source option, and the part you still build yourself.

ComponentBuyOpen sourceYou buildMaturity
Workload identityAWS IAM roles, Entra managed identities, Google Cloud service accounts·Least-privilege policies per app, plus an IAM condition requiring a guardrailGA
Workload and vector DBEKS or ECS, OpenSearch Serverless, Aurora pgvector, Azure AI Search, AlloyDBpgvector, QdrantPer-user access control on retrieved documentsGA
Private networkingAWS PrivateLink for bedrock-runtime and bedrock-mantle, Azure Private Endpoints, Google Private Service Connect·Private DNS, no NAT on AI subnets, SCPsGA
Invocation logs and CloudTrailBedrock model invocation logging to S3 or CloudWatch, Azure API Management LLM logging, Agent Platform request-response logging·Turn logging on, encrypt, set retention, send metadata to SIEMGA
Provider guardrailsAmazon Bedrock Guardrails, Azure AI Content Safety, Google Model Armor·Policy tuning per appGA
Managed modelsAmazon Bedrock, Microsoft Foundry, Gemini Enterprise Agent Platform (formerly Vertex AI)·Pin regions and inference profilesGA
Separate account for PHI workloadsAWS Organizations, Azure subscriptions, Google Cloud projects·SCPs for approved regions and models, and a deny on disabling loggingGA

Rollout steps

#StepWhoEffort
1Create a dedicated AI account with SCPs for regions, models and logging, and confirm BAA coverageCloud security engineer2-4 days
2Create VPC endpoints for bedrock-runtime, bedrock-mantle, S3, KMS and logs, with private DNS and no NATPlatform engineer2-3 days
3Turn on invocation logging to an encrypted S3 bucket and keep apps on bedrock-runtime, or log in the appSecurity engineer2-3 days
4Give each workload its own IAM role and build retrieval with per-user filteringApplication engineer1-3 weeks
5Add provider guardrails and require them in IAM policySecurity engineer1-2 weeks
6Stream log metadata to the SIEM and keep prompt bodies in a bucket with retentionSecurity engineer3-5 days

What you still build

  • Per-user access control on documents pulled into prompts
  • App-level logging for calls native logs miss, like bedrock-mantle on AWS or Azure without API Management
  • Removing prompt text before logs reach the SIEM
  • SCPs and policy checks that stop logging, region or model drift
  • A gateway in front if apps span more than one cloud

Gotchas

  • Bedrock invocation logging is off by default. Turn it on before launch.
  • Bedrock invocation logging doesn't capture calls on the bedrock-mantle endpoint, which AWS recommends for new apps. Use bedrock-runtime or log in your app.
  • CloudTrail records who called a model, not what they sent. Prompts only appear in invocation logs.
  • Azure diagnostic logs don't include prompt or response text. You need API Management LLM logging.
  • Google's request-response logging is opt-in, sampled and writes to BigQuery.
  • Global cross-region inference can process data outside your region. Use in-region or geo profiles for residency.
  • Catalogs differ by cloud. Bedrock now has OpenAI and Anthropic models, but Gemini is only on Google, and features can trail the first-party APIs.
  • Azure Foundry needs three private DNS zones, and a missing zone silently falls back to the public endpoint.
A4.2

Self-hosted open weights

You run the models on GPUs you own. Nothing leaves, and you own everything.
Your cluster, egress denied1234×6ACTORUsers & appsvia SSOWORKLOADBatch & code jobsrepo scans, doc runsCONTROLInternal gatewayauth, quotas, routingSIMPLIFYTELEMETRYCluster logsforward to SIEMSIMPLIFYWORKLOADInference serversvLLM on GPU nodesCONTROLModel registryscanned, signed, pinnedKEEPRISKPublic internetall egress deniedMODELHugging Face / vendoropen-weight models

Data flow

  1. 1Users and batch jobs call one internal, OpenAI-compatible endpoint.
  2. 2The gateway handles SSO, quotas and routing to the right model size.
  3. 3New open-weight models are imported deliberately, never pulled at runtime.
  4. 4The registry scans, signs and pins versions before GPU nodes load them. Scanners catch malicious files, not backdoored weights, so evaluate each new model.
  5. 5Outbound internet is denied, so prompts and outputs never leave the cluster. Offline settings let the stack start without it.
  6. 6Gateway and inference logs stay in-cluster and forward to the SIEM.

Self-hosted open weights: build or buy

Mostly custom

What you can buy for each box in the diagram, the open source option, and the part you still build yourself.

ComponentBuyOpen sourceYou buildMaturity
Inference serversNVIDIA NIM with NVIDIA AI Enterprise. GPUs from AWS, Azure, Google Cloud or neoclouds like CoreWeave, Lambda, NebiusvLLM, SGLang, KServe, llm-dCapacity planning, autoscaling, model evalsGA
Internal gatewayLiteLLM Enterprise, Kong Gateway EnterpriseLiteLLM OSS, Envoy AI Gateway 1.0SSO, quotas, routing by model size and data classGA
Model registry with scanning and signingPrisma AIRS Model Security (formerly Protect AI Guardian), HiddenLayerModelScan, picklescan, OpenSSF model-signing, MLflow, HarborQuarantine import, scan, sign, pin by digest, verify at deployGA
Egress denyCloud security groups, no NAT gatewayCilium, Calico network policiesAllowlist for internal registry and patch mirrorsGA
Cluster logsYour existing SIEMOpenTelemetry, Fluent BitJoin gateway and inference logs by request ID, remove prompt textGA
Model sourceHugging Face, model vendors·Deliberate import process, never pulled at runtimeGA

Rollout steps

#StepWhoEffort
1Pick models with evals on your real tasks and load-test GPU sizingML engineer1-2 weeks
2Build the GPU node pool, autoscaling and subnets with no egressPlatform engineer2-3 weeks
3Build the import pipeline: quarantine, scan, require safetensors, review config code, sign, pinSecurity engineer2-3 weeks
4Stand up the internal gateway with SSO, quotas and routingPlatform engineer1 week
5Forward gateway and inference logs to the SIEM and set up a CVE watch for vLLM, CUDA and driversSecurity engineer1 week
6Run monthly upgrades, model refreshes and capacity reviewsPlatform engineerOngoing, 0.5-3 FTE depending on size

What you still build

  • Model import pipeline with scanning, signing, digest pinning and signature checks at deploy
  • Behavioral evals that look for backdoors and quality regressions
  • Routing by model size and data class
  • GPU capacity planning and autoscaling
  • CVE response process for the serving stack

Gotchas

  • GPU cost and the people to run it dominate. Compare against your managed token bill at the same volume.
  • vLLM had several 2026 code execution CVEs tied to remote model code. Run 0.28.0 or later with trust_remote_code off.
  • Scanners catch malicious pickle files, not backdoored weights. You still need evals.
  • With all egress denied, set offline flags like HF_HUB_OFFLINE and LiteLLM's local cost map, or startup can break.
  • Prisma AIRS Model Security scans only public Hugging Face repos directly. Download private models and scan them locally.
  • Plan two to four months to stand this up, not two weeks.

Common use cases

  • PHI and PII document processing
  • Regulated customer support bots
  • Source code and IP analysis
  • Residency-bound or air-gapped workloads

Key risks

  • Model catalogs differ by cloud
  • Invocation logging off by default, with gaps on newer endpoints
  • Malicious or backdoored open weights
  • You own GPU capacity and every serving-stack CVE

Fast path

  • KEEPIAM roles, no static keys
  • KEEPSeparate cloud account for PHI AI workloads
  • KEEPPrivate networking or egress deny
  • KEEPInvocation logging on, plus app-level logs
  • KEEPRegistry with scanning and pinning (self-hosted)
  • DEFERProvider guardrails at launch
  • SIMPLIFYLogs to bucket before SIEM

Sources

Vendor documentation and announcements we checked for this page. Products are examples of a category, not endorsements.

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