Cloud asset and tenant segregation controls

Cloud environments fail audits less often due to missing controls than due to fuzzy boundaries: what counts as a “tenant,” where assets live, and how isolation is proven. The cloud asset and tenant segregation controls requirement focuses on two operator outcomes: (1) cloud asset governance so you can identify and control what exists, who owns it, and how it is configured; and (2) tenant isolation so data, workloads, and administrative actions cannot cross boundaries you define (customer-to-customer, business unit-to-business unit, prod-to-nonprod, regulated-to-nonregulated).

ISO/IEC 27017 is a cloud security controls code of practice. The licensed control text is not reproduced here, but the intent is clear: implement controls for cloud asset governance and tenant isolation ¹. For a CCO or GRC lead, the fastest path is to treat this requirement as a boundary-control problem with evidence: you must show your tenancy model, the technical mechanisms that enforce it, and test results that demonstrate isolation behavior in practice. Tools can help, but the exam outcome hinges on documentation quality and repeatable verification.

Regulatory text

Provided excerpt (non-licensed summary): “Baseline implementation-intent summary derived from publicly available framework overviews; licensed standard text is not reproduced in this record.”
Requirement summary: “Implement controls for cloud asset governance and tenant isolation.” ¹

What the operator must do

You must be able to demonstrate, with documented design and operating evidence, that:

1. Cloud assets are governed: you know what cloud resources exist, who owns them, how they are classified, and which baselines/policies apply.
2. Tenants are segregated: your defined tenants are isolated by design and enforced controls, and you can show verification that isolation works.

This is less about a single technical setting and more about a defensible model: defined boundaries, controls at those boundaries, monitoring for boundary drift, and periodic validation.

Plain-English interpretation of the requirement

A “tenant” is any boundary where sharing creates unacceptable risk. In practice, tenants commonly include:

• Different customers in a multi-tenant service you operate.
• Different internal business units or legal entities.
• Production vs non-production.
• Regulated workloads (e.g., sensitive customer data) vs general workloads.

The requirement expects you to prevent:

• Data bleed (Tenant A reads Tenant B’s data).
• Control bleed (Tenant A can modify Tenant B’s resources, IAM, keys, logs, or network).
• Blast-radius bleed (a compromise in one tenant quickly propagates into another due to shared identities, flat networks, shared secrets, or weak admin separation).

Who it applies to (entity and operational context)

Entities

• Cloud customers running workloads on IaaS/PaaS/SaaS who must segregate environments, teams, and data domains.
• Cloud providers / SaaS operators hosting multiple customers and responsible for strong tenant isolation in the service architecture. ¹

Operational contexts where auditors focus

• Multi-account or multi-subscription cloud setups with shared identity tooling.
• Shared Kubernetes clusters or shared databases across tenants.
• Centralized logging/monitoring platforms that ingest from multiple tenants.
• CI/CD pipelines that deploy to multiple tenants/environments.
• Managed services where the provider’s support/admin access can bypass tenant boundaries.

What you actually need to do (step-by-step)

Step 1: Define your tenancy model (the boundary contract)

Create a short “Tenancy and Segregation Standard” that answers:

• What is a tenant in your organization (customer, BU, environment, region)?
• What resources must be dedicated vs may be shared (and under what conditions)?
• What is the minimum segregation layer for each workload class (identity, account/subscription, VPC/VNet, cluster, database, KMS keys)?
• Who can approve exceptions and how they are time-bounded?

Operator tip: If you cannot describe your tenancy model on one page, engineering teams will implement “segregation vibes,” and auditors will find inconsistencies.

Step 2: Build a complete cloud asset inventory with ownership and classification

You need an inventory that is accurate enough to answer: “Show me all assets in scope for Tenant X and who owns them.”

• Establish mandatory tags/labels (owner, system, environment, data classification, tenant ID).
• Define the system-of-record (CMDB, cloud asset inventory service, or inventory pipeline).
• Add detective controls for untagged or unknown assets (alerts + ticketing workflow).

Step 3: Choose segregation mechanisms per layer (defense in depth)

Implement segregation across multiple layers. Pick the strongest feasible boundary first, then add layers for resilience.

Common mechanisms (map to your cloud):

• Identity and access: Separate tenants with distinct IAM roles, groups, and permission boundaries; restrict cross-tenant role assumption; enforce MFA and conditional access for admin paths.
• Account/subscription/project separation: Separate tenants into different accounts/subscriptions/projects when the risk profile is high. This reduces blast radius and simplifies evidence.
• Network segmentation: Separate VPCs/VNets/subnets and tightly control peering, routing, and egress; require explicit allowlists for cross-tenant flows.
• Compute/workload isolation: Separate clusters or namespaces with strong policy controls; isolate runtime identities; avoid shared worker nodes for high-risk tenant mixes.
• Data plane segregation: Separate databases/schemas and storage buckets/containers; enforce row-level access only when you can prove it is correct; separate encryption keys per tenant for high-risk data sets.
• Management plane segregation: Restrict who can view/modify logging, KMS, secrets, backups, and monitoring. This is where many “logical isolation” claims fail.

Step 4: Implement preventative guardrails (make the secure path the easy path)

• Infrastructure-as-code templates that “bake in” tenancy boundaries (account structure, network baselines, logging, KMS).
• Policy-as-code that blocks noncompliant deployments (e.g., public storage, missing tags, cross-tenant trust policies).
• Standard patterns for shared services with explicit boundary protections (central logging with tenant-scoped access controls).

Step 5: Validate isolation behavior (required for audit credibility)

The provided control guidance calls this out directly: apply segregation controls and validate isolation behavior ¹.

Build a repeatable validation approach:

• Design review: For each major platform (Kubernetes, data warehouse, message bus), document how tenant isolation is enforced.
• Configuration verification: Evidence from cloud config snapshots/policies that show controls are set (IAM policies, network rules, KMS key policies).
• Isolation tests: Documented tests that attempt cross-tenant access (negative tests) and show denial, plus logs that prove enforcement.
• Ongoing monitoring: Alerts for boundary drift (new peering routes, new cross-account roles, relaxed bucket policies, namespace policy changes).

Step 6: Manage exceptions and shared-responsibility boundaries

Where tenants share resources (shared cluster, shared logging platform), you must document:

• Why sharing is allowed.
• Compensating controls (strong RBAC, tenant-scoped encryption keys, strict audit logging).
• Who approved it and when it expires.
• How you will retest after material changes.

For third parties (including SaaS you consume), document segregation assurances as part of third-party due diligence. If a SaaS tool blends multiple internal tenants, you still own the risk decision.

Required evidence and artifacts to retain

Auditors typically want artifacts that prove both design and operation.

Minimum artifact set (practical)

• Tenancy and Segregation Standard (policy/standard) with approval and version history.
• Cloud asset inventory export showing required metadata (owner, tenant, environment, classification).
• Architecture diagrams: tenant boundaries and shared service boundaries.
• IAM evidence: role definitions, permission boundaries, cross-tenant trust restrictions, admin access procedures.
• Network evidence: segmentation rules, peering approvals, firewall/security group baselines.
• Data isolation evidence: storage policies, database access model, KMS key separation rationale.
• Isolation validation pack: test plans, executed results, and logs showing denied cross-tenant access attempts.
• Exception register: all approved deviations, compensating controls, and expiration dates.
• Change management linkage: tickets/PRs showing review for boundary-impacting changes.

Daydream fit (earned mention): If you already track controls and evidence in Daydream, structure this as an evidence collection workflow tied to your tenancy model. The win is faster audits because you can produce the latest inventory, policies, and validation results without rebuilding the narrative each time.

Common exam/audit questions and hangups

Use these to pre-brief engineering and platform owners.

Auditor question	What they’re testing	What you show
“Define ‘tenant’ in your environment.”	Clarity of boundary	Tenancy model + examples (customer, BU, prod/nonprod)
“Show how Tenant A is prevented from accessing Tenant B.”	Technical enforcement	IAM, network, data controls + negative test results
“How do you know your inventory is complete?”	Asset governance maturity	Inventory method + tagging policy + detection of unknown assets
“Where are logs and keys stored, and who can access them?”	Management plane isolation	Access controls for logging/KMS/secrets, admin procedures
“How are exceptions handled?”	Risk acceptance discipline	Exception register + approvals + compensating controls

Frequent implementation mistakes and how to avoid them

1. Relying on network segmentation alone. Identity misconfigurations bypass network boundaries. Put IAM separation first, then network.
2. Shared admin roles across tenants. This collapses the management plane boundary. Use tenant-scoped admin roles and break-glass procedures with logging.
3. Tagging without enforcement. “Required tags” that aren’t blocked or monitored do not support governance claims. Add preventative policy checks and detective alerts.
4. Row-level security without proof. Logical controls can be correct, but auditors want validation evidence. Keep test cases and results.
5. Centralized tooling that becomes a backdoor. CI/CD, monitoring, backup, and support tools often have broad access. Document and restrict those paths explicitly.

Enforcement context and risk implications

No public enforcement cases were provided in the supplied source catalog for this requirement, so this page does not list specific cases. Practically, weak segregation increases the likelihood and impact of cross-tenant data exposure, unauthorized administrative action, and lateral movement after compromise. From a governance standpoint, the common failure mode is inability to prove isolation works under real operating conditions.

Practical 30/60/90-day execution plan

First 30 days: define, scope, and stop the bleeding

• Publish the tenancy definition and minimum segregation requirements (policy/standard).
• Identify “highest risk sharing” areas (shared clusters, shared databases, shared admin roles) and open remediation tickets.
• Implement mandatory asset tags and start inventory exports for in-scope cloud accounts/subscriptions/projects.
• Stand up an exception register with approval workflow.

Days 31–60: implement guardrails and baseline validation

• Enforce preventative policies for tagging and high-risk misconfigs (public storage, cross-tenant trust).
• Implement baseline segmentation for identity and network in the highest risk tenants/environments.
• Write the isolation test plan and execute initial negative tests for at least one representative stack (app + data + admin plane).
• Centralize evidence collection (policy, diagrams, configs, test results) in your GRC system.

Days 61–90: expand coverage and make it repeatable

• Extend segregation patterns to remaining tenants and shared services.
• Add drift monitoring and alerting for boundary-impacting changes (IAM trust, peering routes, storage policies, KMS key policy edits).
• Formalize change management checks: “Does this change cross a tenant boundary?” as a required reviewer question.
• Run a tabletop scenario for cross-tenant exposure and verify logs support investigation and containment.

Frequently Asked Questions

What counts as a “tenant” for this requirement?

A tenant is any boundary where you must prevent data or control-plane access across groups, such as customer-to-customer, business unit-to-business unit, or prod-to-nonprod. Define it explicitly in your tenancy standard and apply it consistently across assets and access models.

Do I need separate cloud accounts/subscriptions for every tenant?

Not always. Separate accounts/subscriptions are strong isolation, but you can use logical segmentation if you can prove enforcement and keep validation evidence that auditors accept for your risk profile.

How do we prove tenant isolation in a shared Kubernetes cluster?

Document the isolation design (namespaces, network policies, workload identities, admission controls) and run negative tests that attempt cross-namespace and cross-tenant access. Retain policy exports and logs that show access was denied.

What evidence is most commonly missing during audits?

Teams often have some controls configured but lack a clean tenancy definition, an inventory that maps assets to tenants, and executed isolation test results. Auditors need a coherent story with artifacts.

How should we handle shared services like centralized logging or CI/CD?

Treat shared services as high-risk management-plane components. Restrict access with tenant-scoped roles, isolate secrets, and document why sharing is acceptable plus what monitoring detects boundary drift.

Where does third-party due diligence fit into tenant segregation?

If a third party hosts or processes tenant data (or provides admin tooling across tenants), your due diligence should confirm their segregation model and your configuration responsibilities. Document those assumptions as part of your control narrative.

Related compliance topics

• 2025 SEC Marketing Rule Examination Focus Areas
• Access and identity controls
• Access Control (AC)
• Access control and identity discipline
• Access control management

Footnotes

1. ISO/IEC 27017 overview