SA-8(6): Minimized Sharing

To meet the sa-8(6): minimized sharing requirement, you must design and configure your system so components share only what they must to perform their function—no broad network trust, no default cross-tenant access, and no “everyone can see everything” service-to-service permissions. Operationalize this by defining explicit sharing boundaries, enforcing least-privilege data flows, and keeping evidence that the design is implemented and maintained. ¹

Key takeaways:

• Treat “sharing” as an architectural property: data, memory, CPU, network, identity, and logs all count. ²
• Convert the principle into enforceable rules: segmentation, scoped identities, minimal APIs, and explicit allow-lists. ²
• Keep assessor-ready proof: diagrams, control narratives, configs, and change records that show minimized sharing stays true over time. ¹

SA-8(6) sits in the “Security and Privacy by Design” family and is easy to misunderstand because the requirement is short, but the operational footprint is large. The control is asking you to implement a design principle: prevent unnecessary coupling between system components and prevent unnecessary exposure between tenants, environments, and services. That means your architecture should not rely on shared resources or shared privileges unless you can justify them and control them tightly. ²

For a CCO or GRC lead, the fastest path is to translate “minimized sharing” into a set of reviewable system design decisions and configuration standards. Then you connect those decisions to build/release gates and recurring evidence collection so the principle doesn’t degrade as teams ship changes. In practice, assessors look for two things: (1) whether you have defined boundaries and constraints, and (2) whether your technical implementation matches your diagrams and narratives. ²

This page gives you requirement-level guidance you can hand to engineering: what to decide, what to configure, and what to retain as proof.

Regulatory text

Control requirement (excerpt): “Implement the security design principle of minimized sharing in {{ insert: param, sa-08.06_odp }}.” ¹

What the operator must do

You must be able to show that your system’s design and configuration intentionally limit sharing of resources and information between:

• components (services, apps, functions),
• trust zones (prod/non-prod, admin/user planes),
• tenants/customers (if multi-tenant),
• users and roles,
• and third parties (including managed services and SaaS integrations),

…to only what is needed for authorized functionality. Your implementation should be demonstrable through architecture artifacts and technical controls (segmentation, IAM scoping, isolation controls, explicit interfaces). ²

Plain-English interpretation (what “minimized sharing” means in real systems)

“Minimized sharing” means you design systems so that compromise or failure in one area does not automatically expose other areas. In concrete terms, you avoid:

• broad flat networks where services can talk to everything by default,
• shared admin credentials or shared service accounts across apps,
• shared storage buckets, queues, or databases across unrelated workloads without strict access boundaries,
• shared compute where one tenant’s workload can influence another’s security boundary (without compensating isolation),
• shared logs that expose sensitive customer or regulated data across teams.

It does not mean “no sharing ever.” It means “sharing is explicit, justified, constrained, and monitored.” ²

Who it applies to (entity and operational context)

This control is commonly assessed for:

• Federal information systems implementing NIST SP 800-53 controls. ²
• Contractor systems handling federal data where NIST SP 800-53 is contractually flowed down or used as the control baseline. ²

Operationally, SA-8(6) matters most when you have:

• microservices or service-oriented architectures,
• cloud environments with multiple accounts/subscriptions/projects,
• container/Kubernetes platforms,
• multi-tenant SaaS products,
• shared CI/CD runners and build services,
• shared “platform” services (logging, metrics, secrets, IAM).

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

Use this as an implementation checklist you can assign to engineering and track in your GRC system.

Step 1: Define “sharing boundaries” and document them

Create a short “Minimized Sharing Design Standard” that defines the boundaries you enforce, such as:

• tenant boundary (customer-to-customer isolation),
• environment boundary (prod vs non-prod),
• trust zone boundary (internet-facing vs internal),
• admin plane boundary (management interfaces separated from data plane),
• third-party boundary (external integrations isolated and scoped).

Deliverable: one-page standard plus a system-specific boundary statement in your SSP/control narrative. ²

Step 2: Inventory where sharing exists today (and why)

Run a focused architecture review to identify shared:

• networks/VPCs, subnets, peering, security groups/firewalls,
• IAM roles, service accounts, groups, and permission sets,
• data stores (DBs, object storage, caches), message buses, shared file systems,
• secrets stores, KMS keys, certificates,
• observability pipelines and log sinks,
• CI/CD runners, build agents, artifact repositories.

For each shared element, record:

• what is shared,
• who can access it,
• the business justification,
• the intended control to constrain it (segmentation, ACLs, encryption keys per tenant, etc.).

Deliverable: “Sharing Register” (a structured table) tied to your system boundary diagram. ²

Step 3: Convert the principle into enforceable technical rules

Pick controls that reduce default trust and reduce blast radius:

Network

• Segment by environment and trust zone.
• Default-deny east-west traffic; allow-list only required ports and peers.
• Separate management endpoints from application data paths.

Identity and access

• Separate service identities per application/service (no “shared runtime role”).
• Scope permissions to specific resources (resource-level policies where supported).
• Avoid long-lived shared credentials; prefer short-lived tokens from an identity provider.

Data

• Separate storage by tenant or enforce strong logical separation with tested access controls.
• Minimize shared encryption keys; use key separation where it reduces cross-tenant exposure.
• Restrict data replication and exports to approved paths only.

Application/API

• Create minimal APIs; avoid “admin” endpoints accessible from general service networks.
• Enforce per-tenant authorization checks in every data-access path.
• Reduce shared libraries/components that run with elevated privileges unless necessary.

Platform

• Isolate CI/CD permissions from runtime permissions.
• Restrict who can read centralized logs that may contain sensitive fields.

Deliverable: engineering standards (IAM patterns, network patterns, data tenancy patterns) plus implementation tickets per gap. ²

Step 4: Add build/release gates so sharing does not creep back

Most “minimized sharing” failures are regressions: a new service gets deployed with a permissive role or placed on a shared network “temporarily.”

Add lightweight gates:

• IaC policy checks for overly broad network rules and IAM permissions
• required architecture review for new shared services (logging, queues, data platforms)
• change approvals for modifications that cross defined boundaries (e.g., new peering, new cross-account role trust)

Deliverable: documented SDLC gate + example pipeline evidence (screenshots/exports) showing checks in place. ²

Step 5: Operational monitoring and periodic validation

Minimized sharing is also operational:

• alert on policy drift (new wildcard permissions, new broad security group rules),
• periodically validate tenant isolation and authorization boundaries with targeted tests,
• review third-party connections for scope creep.

Deliverable: recurring review procedure and logs of completed reviews with findings and closure. ²

Step 6: Assign ownership and recurring evidence collection

Make the control assessable:

• Control owner: usually Security Architecture or Platform Security; shared accountability with Cloud/IAM owners.
• Evidence cadence: tie to change management and periodic review cycles appropriate to your system.

If you use Daydream, map SA-8(6) to a named owner, a written procedure, and a recurring evidence list so audits stop being diagram-chasing exercises and become routine exports and approvals. ¹

Required evidence and artifacts to retain

Keep artifacts that prove design intent and real configuration match.

Core artifacts

• System boundary diagram(s) showing trust zones, tenants, and external connections
• “Minimized Sharing” design standard (org-level) and system-specific narrative (SSP section)
• Sharing Register: list of shared components with justification and constraints
• Network segmentation evidence: firewall/security group rules, routing/peering documentation
• IAM evidence: role definitions, trust policies, permission sets, group memberships (exported)
• Data isolation evidence: tenancy model documentation, access policy examples, key management approach
• SDLC gate evidence: IaC policy results, pull request templates requiring boundary review, approval records
• Periodic review records: drift reports, exception reviews, remediation tickets

Exceptions

• Exception/risk acceptance records for unavoidable sharing (with compensating controls and expiry)

Assessors generally accept screenshots, exports, and signed design reviews if they are consistent, dated, and traceable to the system. ²

Common exam/audit questions and hangups

Expect these lines of questioning:

1. “Show me your boundaries.” Where is the formal definition of zones, tenants, and trust levels? ²
2. “Where do components share resources?” List shared networks, IAM roles, databases, log sinks, and CI/CD agents. ²
3. “Prove sharing is minimized.” What prevents workload A from accessing workload B by default? Show deny-by-default and explicit allow-lists. ²
4. “How do you prevent drift?” What stops a developer from adding * permissions or opening broad inbound rules? ²
5. “How do you handle third parties?” Are integrations scoped to the minimum needed and isolated from core data planes? ²

Hangup to plan for: auditors often conflate “shared platform” with “noncompliant.” Your job is to show the constraints, separation model, and monitoring that make the shared platform safe. ²

Frequent implementation mistakes and how to avoid them

Mistake	Why it fails SA-8(6)	Fix
One shared “service role” for many services	Creates broad lateral movement paths	Issue per-service identities; scope permissions per resource
Flat internal network	Implicit trust across services	Segment, default-deny east-west, allow-list dependencies
Shared data stores without clear tenancy controls	Increases cross-tenant exposure risk	Separate by tenant where feasible or implement strong logical isolation and test it
“Temporary” exceptions that never expire	Sharing creep becomes baseline	Require expiry dates and periodic re-approval for exceptions
No evidence trail	Control may exist in minds, not in artifacts	Maintain diagrams, exports, and review records tied to change history

Risk implications (why assessors care)

Minimized sharing reduces blast radius. If one service is compromised, the attacker should not automatically gain access to unrelated data, unrelated admin functions, or other tenants’ resources. In federal and contractor contexts, a failure here often cascades into findings across IAM, segmentation, and data protection controls because shared privileges and shared networks defeat multiple safeguards at once. ²

Practical execution plan (30/60/90-day)

First 30 days (establish the control)

• Name the SA-8(6) control owner and backup.
• Publish the “Minimized Sharing Design Standard” (short, enforceable rules).
• Create the initial boundary diagram and Sharing Register for the in-scope system.
• Identify the highest-risk sharing hotspots (broad IAM, flat networks, shared sensitive data stores) and open remediation work.

By 60 days (implement and prove)

• Implement priority segmentation and IAM scoping changes.
• Add IaC and CI/CD checks for the most common regressions (wildcards, broad ingress/egress, cross-account trust).
• Document exceptions with justification, compensating controls, and expiry.
• Run a validation review: confirm diagrams match deployed reality; update artifacts where needed.

By 90 days (make it repeatable)

• Establish recurring drift reviews and evidence exports.
• Add an architecture review trigger for any new shared service or cross-boundary connection.
• Build an “assessor packet” that includes: diagrams, Sharing Register, sample configs, gate evidence, and last review results.
• In Daydream (or your GRC system), tie SA-8(6) to the procedure and recurring evidence tasks so the control stays continuously assessable. ¹

Frequently Asked Questions

Does “minimized sharing” require physical separation for each tenant?

No. SA-8(6) requires minimized sharing as a design principle, which can be satisfied with strong logical isolation if you can demonstrate boundaries, constraints, and validation. ²

What counts as “sharing” for SA-8(6)?

Treat it broadly: networks, identities, credentials, storage, compute, logs, and admin functions. If compromise in one area exposes another due to shared access, it’s in scope. ²

How do I show compliance if we rely on shared cloud services (logging, KMS, IAM)?

Document the shared service in the Sharing Register, explain why it must be shared, and show controls that constrain access (scoped roles, separate keys/policies, restricted log access). ²

What’s the minimum evidence an auditor will accept?

Provide a boundary diagram, a written minimized-sharing standard/narrative, and configuration evidence for segmentation and IAM scoping. Add change records that show these controls stay in place. ²

How do we handle exceptions where sharing is required for business reasons?

Use time-bound exceptions with documented risk acceptance and compensating controls, then review them on a recurring basis. Keep the exception record with approvals and closure evidence. ²

Where does this fit relative to least privilege?

Least privilege focuses on who can do what; minimized sharing focuses on how system components are coupled and what they can access by default. In practice you implement both through segmentation and scoped identities. ²

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON

2. NIST SP 800-53 Rev. 5