SC-36(2): Synchronization

To meet the sc-36(2): synchronization requirement, you must identify the “duplicate systems or system components” in scope and implement a repeatable method to keep them aligned so they behave consistently and don’t drift. Operationally, that means defining what “synchronized” means for each duplicate pair, automating updates where possible, and keeping audit-ready evidence that synchronization is working. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Key takeaways:

• Build and maintain an inventory of in-scope duplicate components, then assign a synchronization owner per duplicate set. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Define synchronization attributes (config, data, keys, rules, versions), cadence, and drift tolerances, then enforce them with technical controls and monitoring. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Keep evidence that synchronization is designed, operating, and exceptions are approved and time-bounded. (NIST SP 800-53 Rev. 5 OSCAL JSON)

SC-36(2) is a control enhancement focused on a common failure mode: duplicated systems or components that should match, but don’t. “Duplicates” show up everywhere in modern environments, such as active/active services, warm standbys, load-balanced nodes, clustered databases, golden images, container base images, IAM policy replicas across accounts, or parallel network/security devices meant to enforce the same rules. If those duplicates drift, you can get inconsistent security enforcement, unpredictable recovery behavior, and audit findings that look like basic operational hygiene gaps.

The practical challenge is that NIST leaves the scoping open: the control text requires you to synchronize “the following duplicate systems or system components,” which your organization must explicitly define in a parameter. Your job as a Compliance Officer, CCO, or GRC lead is to force clarity: which duplicates matter, what “synchronized” means for each, who owns it, and what evidence proves it works. This page gives you requirement-level guidance you can hand to engineering and then assess against during an audit. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Regulatory text

Control requirement (excerpt): “Synchronize the following duplicate systems or system components: {{ insert: param, sc-36.02_odp }}.” (NIST SP 800-53 Rev. 5 OSCAL JSON)

Operator meaning: You must (1) name the specific duplicates in scope (the parameter), and (2) implement synchronization so those duplicates remain aligned. Assessors will expect your SSP/control narrative to explicitly list the duplicates, explain the synchronization mechanism, and show operational evidence that drift is detected and corrected. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Plain-English interpretation

SC-36(2) requires you to prevent “security drift” across duplicate components that are supposed to be equivalent. Synchronization can mean different things depending on the technology:

• Configuration synchronization: same baseline configuration, hardening, and settings.
• Policy/rule synchronization: same firewall rules, WAF rules, IAM policies, routing policies.
• Data synchronization: replicated databases, object stores, directory services.
• Software/version synchronization: same OS patch level, agent versions, container base image digest.
• Cryptographic/material synchronization: consistent certificate deployment, key versions, trust stores (where appropriate and safe).

You do not need everything to be identical all the time. You do need a documented definition of “in-sync” plus controls that keep the duplicates within that definition, with managed exceptions. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Who it applies to

Entity scope: Federal information systems and contractor systems handling federal data (for example, environments supporting federal contracts that adopt NIST SP 800-53 controls). (NIST SP 800-53 Rev. 5 OSCAL JSON)

Operational context where this becomes “real”:

• High-availability and disaster recovery: primary vs standby stacks, multi-region deployments, DR “pilot light” environments.
• Horizontal scaling: multiple web/app nodes behind load balancers, Kubernetes worker pools, autoscaling groups.
• Security enforcement duplication: redundant firewalls, duplicate security groups across accounts, parallel proxies.
• Shared services: replicated identity providers, DNS, NTP, logging pipelines, EDR managers in segregated enclaves.

If you have duplicates but no synchronization approach, auditors tend to treat it as a control design gap plus an availability and security risk. (NIST SP 800-53 Rev. 5 OSCAL JSON)

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

Step 1: Define the sc-36.02 parameter (“what duplicates are in scope”)

Create an explicit list of duplicate systems/components that must be synchronized. Keep it short enough to manage, but broad enough to cover meaningful risk.

Practical scoping method:

1. Start with systems supporting federal data or mission-critical services.
2. List duplicates that (a) affect security enforcement or (b) are used for failover/continuity.
3. Exclude duplicates that are intentionally different by design, but document why.

Deliverable: “SC-36(2) Synchronization Scope” register (table format). (NIST SP 800-53 Rev. 5 OSCAL JSON)

Step 2: Define “synchronized” per duplicate set

For each duplicate set, document:

• Synchronization attributes: what must match (configs, rules, versions, datasets).
• Source of truth: where the authoritative definition lives (IaC repo, config management, directory).
• Allowed drift: what differences are acceptable (and under what approval).
• Detection method: how you know drift happened (CI checks, config compliance scans, replication status).
• Remediation method: how drift is corrected (automated rollouts, reconciliation jobs, runbooks).
• Exception path: how teams request, approve, and time-bound deviations.

Deliverable: A one-page “Synchronization Specification” per duplicate set (or a standardized template). (NIST SP 800-53 Rev. 5 OSCAL JSON)

Step 3: Implement technical synchronization controls

Pick mechanisms that match your environment; assessors care less about the tool and more about repeatability and evidence.

Common implementation patterns:

• Infrastructure/config: Infrastructure-as-code with enforced CI gates; configuration management with desired-state enforcement.
• Policy/rules: Central policy-as-code and automated distribution; version-controlled firewall/WAF rule deployments.
• Data: Database replication with health checks; immutable backup + restore tests where replication is not appropriate.
• Software versions: Standard images; controlled rollout pipelines; package pinning and approved repositories.

Control owner assignment: Name an engineering owner and a GRC control owner. The engineering owner fixes drift; the GRC owner validates evidence and manages exceptions. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Step 4: Instrument drift monitoring and response

Synchronization without monitoring fails quietly.

Minimum operational expectations:

• Alerting: drift or replication failures create tickets.
• Triage: severity rules based on what the duplicate does (security enforcement vs non-critical).
• Root cause: capture why drift occurred (manual change, failed pipeline, emergency patch).
• Closure: document re-synchronization and validation.

Deliverable: Drift ticket samples and a runbook that maps alerts to actions. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Step 5: Make exceptions explicit and auditable

Duplicates sometimes must diverge temporarily (incident response, urgent patches, region-specific constraints). Your control survives audits if exceptions are controlled.

Exception minimums:

• documented rationale
• approver
• expiration condition
• compensating controls (if applicable)
• re-sync plan and validation evidence

Deliverable: Exception log tied to the synchronization scope register. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Step 6: Operationalize evidence collection (don’t “handcraft” at audit time)

Map SC-36(2) to:

• the control owner,
• the procedure,
• recurring evidence artifacts.

If you use Daydream, this is where it fits naturally: store the scope register, specs, and recurring evidence as a control record with ownership, review tasks, and an audit-ready evidence trail. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Required evidence and artifacts to retain

Keep evidence that covers design, implementation, and operation:

Core artifacts (audit staples):

• SC-36(2) synchronization scope register (the parameter list) (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Synchronization specifications/templates per duplicate set (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Architecture diagrams showing duplicates and replication/config flows (NIST SP 800-53 Rev. 5)
• Change management records for synchronization mechanisms (pipelines, IaC merges, config baseline approvals) (NIST SP 800-53 Rev. 5)
• Monitoring/alert evidence: dashboards, alerts, tickets, and closure notes for drift events (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Exception log with approvals and expirations (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Assessment mapping: control narrative that explains how synchronization is achieved and verified (NIST SP 800-53 Rev. 5)

Common exam/audit questions and hangups

Assessors tend to probe these areas:

• “Show me the duplicates.” If your parameter list is vague, you will burn time in interviews and still risk a finding. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• “What does synchronized mean here?” “They’re usually the same” does not pass. You need defined attributes and a validation method. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• “How do you detect drift?” Manual spot checks rarely satisfy. Show automated checks or systematic monitoring evidence. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• “What happens when it breaks?” Provide tickets/runbooks and at least one example of a drift event being detected and corrected. (NIST SP 800-53 Rev. 5)
• “Who owns this?” Shared ownership without a named accountable party creates control-operation gaps. (NIST SP 800-53 Rev. 5)

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails	Fix
Listing “all systems” as duplicates	Unassessable scope; no operational focus	Define a bounded list tied to risk and architecture (NIST SP 800-53 Rev. 5 OSCAL JSON)
Treating sync as a one-time project	Drift returns after the audit	Build monitoring + recurring evidence capture (NIST SP 800-53 Rev. 5)
No definition of acceptable drift	Teams disagree during incidents	Write explicit drift tolerances and exception criteria (NIST SP 800-53 Rev. 5 OSCAL JSON)
Manual synchronization steps	Error-prone, hard to prove	Use pipelines/IaC/config management with logs (NIST SP 800-53 Rev. 5)
Exceptions live in chat	No audit trail	Formal exception log with approvals and expiry (NIST SP 800-53 Rev. 5 OSCAL JSON)

Enforcement context and risk implications

No public enforcement cases were provided in the source material for this specific control enhancement, so you should treat SC-36(2) primarily as an assessment-readiness and operational resilience requirement under NIST-based programs. The practical risk is straightforward: duplicates that drift can create inconsistent security enforcement (policy gaps), failed failovers (availability events), and unreliable recovery (integrity concerns). (NIST SP 800-53 Rev. 5 OSCAL JSON)

Practical 30/60/90-day execution plan

First 30 days (stabilize scope and ownership)

• Name the in-scope duplicates (populate the sc-36.02 parameter list) and get system owner sign-off. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Assign a single accountable engineering owner per duplicate set and a GRC owner for evidence. (NIST SP 800-53 Rev. 5)
• Draft synchronization specs for the highest-risk duplicates (security enforcement and DR components first). (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Create an exceptions register and start logging any known divergence immediately. (NIST SP 800-53 Rev. 5 OSCAL JSON)

By 60 days (implement repeatable synchronization + monitoring)

• Implement or tighten the synchronization mechanism for each in-scope duplicate set (IaC/config management/replication with documented source of truth). (NIST SP 800-53 Rev. 5)
• Stand up drift detection and connect alerts to ticketing with defined triage ownership. (NIST SP 800-53 Rev. 5)
• Run one tabletop or operational test per critical duplicate set: “simulate drift, detect it, restore sync, document proof.” (NIST SP 800-53 Rev. 5)

By 90 days (make it audit-ready and sustainable)

• Finalize control narrative, scope register, and evidence map for SC-36(2). (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Establish a recurring evidence routine: periodic drift reports, sample tickets, and exception reviews. (NIST SP 800-53 Rev. 5)
• Store artifacts in a single system of record (for example, Daydream) and assign review tasks so evidence accrues continuously. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Frequently Asked Questions

What counts as a “duplicate system or system component” for SC-36(2)?

Treat anything designed to be functionally equivalent and interchangeable as a duplicate, especially HA nodes, DR stacks, replicated security devices, and replicated policy/config endpoints. Document your list explicitly in the sc-36.02 parameter scope. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Do duplicates have to be identical at all times?

No. You need a documented definition of “in-sync” and a method to keep components within that definition, plus controlled exceptions when they must diverge. Auditors look for clarity and proof of operation. (NIST SP 800-53 Rev. 5 OSCAL JSON)

How should we handle emergency changes that break synchronization?

Allow emergency divergence through an exception workflow with an approver, expiration condition, and a re-sync plan. Keep the ticket trail that shows detection, approval, remediation, and validation. (NIST SP 800-53 Rev. 5)

What evidence is most persuasive in an assessment?

A scoped list of duplicates, written synchronization specs, automated drift detection outputs, and tickets showing at least one drift event resolved end-to-end are usually stronger than policy text alone. Keep exceptions documented and time-bounded. (NIST SP 800-53 Rev. 5 OSCAL JSON)

We use multiple cloud accounts and regions. How do we show policy synchronization?

Use a single source of truth (policy-as-code or centralized config) and automated deployment to each account/region. Provide commit history, pipeline logs, and drift reports that compare deployed state against the source baseline. (NIST SP 800-53 Rev. 5)

How do we operationalize SC-36(2) in a GRC tool without creating busywork?

Track the duplicate sets as control sub-items with named owners, link each to its synchronization spec, and attach recurring evidence (drift scans, tickets, exception reviews). Daydream fits well as the evidence system of record because it keeps procedures and artifacts tied to the control. (NIST SP 800-53 Rev. 5 OSCAL JSON)