CP-6(3): Accessibility

CP-6(3) requires you to proactively identify how an area-wide disaster could prevent access to your alternate storage site, then document explicit mitigation actions so backups remain reachable when you need them most ¹. Operationalize it by threat-modeling site accessibility, adding redundant access paths and custody options, and keeping testable runbooks and evidence.

Key takeaways:

• Focus on “can we physically and logically reach stored backups during regional disruption,” not just “do we have backups” ¹.
• Document specific mitigations per accessibility risk (transport, network, identity, third party dependencies), with owners and triggers.
• Retain evidence that the mitigations exist and work: diagrams, contracts, runbooks, test results, and exception records.

The cp-6(3): accessibility requirement sits in the contingency planning family and targets a common failure mode: organizations store backups offsite, but a regional incident makes that “alternate storage site” unreachable. CP-6(3) forces you to treat accessibility as a first-class design constraint. You must identify the ways an area-wide disruption or disaster could block access to the alternate storage site and outline explicit mitigation actions ¹.

For a CCO or GRC lead, the fastest path is to turn CP-6(3) into a small, auditable package: a scoped set of storage locations, a shortlist of credible “area-wide” scenarios, a risk-to-mitigation matrix, and test artifacts that prove you can retrieve what you stored. Done well, CP-6(3) also improves recovery time predictability and reduces executive surprise during incidents, because you have already answered practical questions like “What if the region is inaccessible?” and “What if our people cannot travel?” without improvising.

This page gives requirement-level guidance you can hand to control owners to implement quickly, with a bias toward evidence and examiner-ready outputs.

Regulatory text

Requirement (CP-6(3): Accessibility): “Identify potential accessibility problems to the alternate storage site in the event of an area-wide disruption or disaster and outline explicit mitigation actions.” ¹

Operator meaning: You must (1) enumerate credible ways you could lose access to your alternate storage site during a regional event, and (2) document specific actions that reduce those risks and keep backup retrieval viable. “Explicit” means named actions, owners, and conditions for use; not generic statements like “use redundancy.” ¹

Primary compliance outcome: During a disaster, you can still reach backup media/data, authorize access, and transport or restore it within your recovery expectations because accessibility dependencies were identified and mitigated in advance.

Plain-English interpretation (what CP-6(3) is really asking)

CP-6(3) is an accessibility stress test for backup storage. You are not being asked to prove you have an alternate storage site; you are being asked to prove you can get to it when the surrounding area is disrupted.

“Accessibility problems” usually fall into four buckets:

• Physical access: roads closed, curfews, facility lockouts, staff cannot travel, unsafe conditions.
• Network access: regional ISP outage, peering problems, blocked routes, DDoS spillover, cloud region connectivity issues.
• Identity and authorization: MFA outage, IdP unavailable, break-glass accounts missing, privileged access tool down.
• Third party dependencies: storage provider operational outage, courier unavailable, colocation access restrictions, contract limitations.

Your job is to identify these problems for your specific storage design and write down mitigations that you can execute under pressure.

Who it applies to (entity and operational context)

CP-6(3) is relevant to:

• Federal information systems implementing NIST SP 800-53 controls ².
• Contractor systems handling federal data where NIST SP 800-53 is a contractual or assessment basis ².

Operationally, it applies anywhere you have an “alternate storage site,” including:

• Backup repositories (cloud object storage, backup appliances, tape vaults).
• Replicated storage used for recovery (warm standby storage, immutable backup stores).
• Managed backup services operated by a third party.

If your alternate storage is entirely within the same metro area, CP-6(3) becomes more critical because “area-wide” events can hit both primary and alternate locations.

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

Use this as an implementation runbook for the cp-6(3): accessibility requirement.

Step 1: Define scope and ownership

1. List in-scope alternate storage sites (include cloud regions/accounts, colocation vaults, tape vendors, SaaS backup targets).
2. Assign a control owner (typically Infrastructure/IT Ops, Backup/Storage team, or SRE) and a GRC owner for evidence collection.
3. Confirm recovery assumptions that depend on that site (systems relying on it, restore pathways).

Deliverable: Control scope statement + owner assignment in your control inventory.

Step 2: Identify “area-wide disruption” scenarios that matter to you

Create a concise scenario set tied to your footprint. Keep it plausible and testable. Examples:

• Regional natural disaster affecting transportation and power.
• Widespread civil emergency restricting movement.
• Regional network outage affecting connectivity to the site/provider.
• A cloud region impairment affecting access to storage services.

Deliverable: Scenario list with a short narrative (“what breaks and why”).

Step 3: Map accessibility dependencies (physical + logical)

For each alternate storage site, document dependencies in a simple table:

Dependency area	Questions to answer	Typical evidence
Physical entry	Who can enter, how, and under what conditions?	Site access procedure, badge/escort rules, emergency contacts
Transport	How would media/people move if roads/air travel are constrained?	Courier contract terms, alternate courier, internal chain-of-custody
Network path	How do restores reach production? What network components are required?	Network diagrams, VPN/Direct Connect design, DNS dependencies
Identity	How do admins authenticate if primary IdP is down?	Break-glass procedure, offline MFA codes, privileged account inventory
Provider ops	What if the third party is degraded?	SLA/BCP clauses, status escalation path, multi-region design notes

Deliverable: “Accessibility dependency map” per site.

Step 4: Identify accessibility problems (failure modes)

Convert dependencies into explicit failure modes. Examples:

• Staff cannot physically reach a vault location due to regional travel restrictions.
• The only restore path requires a corporate VPN endpoint hosted in the impacted region.
• Backup encryption keys are only accessible via a key management service tied to the impacted environment.
• A single third party (courier or storage provider) is a choke point during widespread disruption.

Deliverable: Failure-mode list per site.

Step 5: Outline explicit mitigation actions (the heart of CP-6(3))

For each failure mode, document mitigations with:

• Action (specific change or procedure)
• Owner
• Trigger condition (when to invoke)
• How to execute (link to runbook)
• Residual risk/exception (if not fully mitigated)

Common mitigation patterns:

• Geographic separation: add a second alternate storage site in a different region or metro area.
• Multiple access methods: ensure restore access works over more than one path (private link plus internet failover).
• Identity resilience: create audited break-glass access that does not depend on the primary IdP.
• Key escrow and recovery: ensure decryption keys are recoverable during outages without weakening security controls.
• Third party redundancy: contract secondary courier/vault option or ensure provider supports cross-region access.
• Pre-staged restore capability: keep a “restore environment” pattern that can be brought up outside the impacted area.

Deliverable: Risk-to-mitigation matrix that reads like an execution plan, not a narrative.

Step 6: Test the mitigations (tabletop + technical)

CP-6(3) expects mitigations to be real, not theoretical. Build a test cadence that your program can sustain:

• Tabletop: walk through an “area-wide disruption” scenario and execute the runbook steps on paper with named roles.
• Technical validation: prove at least one restore path works when you remove a key dependency (for example, simulate IdP unavailability or primary network path failure in a controlled way).

Deliverable: Exercise report + restore test record + corrective action tickets.

Step 7: Operationalize as BAU (business-as-usual)

1. Add CP-6(3) checks to change management (storage changes, network changes, identity changes).
2. Tie evidence collection to recurring workflows so audit prep is not a scramble.
3. Track exceptions with expirations and compensating controls.

Deliverable: Control operating procedure + evidence calendar.

Required evidence and artifacts to retain

Auditors typically want proof of identification, mitigation, and operational testing. Keep:

• CP-6(3) control narrative (what you do, who does it, tools used).
• Inventory of alternate storage sites (including third party providers in scope).
• Accessibility dependency maps (network and identity diagrams; physical access notes).
• Risk-to-mitigation matrix with owners and triggers.
• Runbooks: restore procedures, break-glass access, emergency contact lists.
• Exercise records: tabletop minutes, scenarios used, after-action items.
• Restore test evidence: logs/screenshots, tickets, reports showing success/failure and remediation.
• Third party artifacts: relevant contract/SOW clauses, escalation paths, attestation reports you rely on (if applicable).
• Exception register entries where mitigations are not yet in place.

Tip: In Daydream, teams commonly package this as a single “CP-6(3) evidence binder” mapped to the control owner, implementation procedure, and recurring artifacts so assessments are repeatable rather than bespoke.

Common exam/audit questions and hangups

Expect these lines of questioning:

• “Show me the alternate storage sites in scope and how you determined them.”
• “What ‘area-wide disruption’ scenarios did you consider, and why are they relevant?”
• “Where is the documented list of accessibility problems, and how was it created?”
• “Point to mitigations that are explicit. Who owns them? Where are the runbooks?”
• “Show evidence you tested accessibility under degraded conditions.”
• “If you rely on a third party storage provider, what happens if that provider or region is unavailable?”

Common hangup: teams provide a DR plan but cannot show site accessibility analysis. CP-6(3) is narrower and more concrete than a general BCP statement.

Frequent implementation mistakes (and how to avoid them)

1. Mistake: Treating “alternate storage exists” as compliant.
   Fix: Document how you will access it during regional disruption, including identity, network, and physical constraints ¹.

2. Mistake: Single-path restores.
   Fix: Build at least one independent restore path that does not share the same regional dependencies as production (network, IdP, or staff travel).

3. Mistake: Vague mitigations (“we have redundancy”).
   Fix: Write mitigations as executable actions with owners, triggers, and linked runbooks.

4. Mistake: No third party failure assumptions.
   Fix: Add provider outage and contract constraints to the failure-mode list. Document escalation and alternatives.

5. Mistake: No evidence trail.
   Fix: Predefine what artifacts you will save after each test or change. Store them in a controlled repository with retention aligned to your audit cycle.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for CP-6(3). Practically, the risk is operational: inaccessible backups can convert a recoverable outage into prolonged downtime and data loss, and it can derail incident response commitments to customers and regulators. For federal and contractor environments, a CP-6(3) gap often shows up as an assessment finding because evidence is missing or mitigations are not testable ¹.

Practical 30/60/90-day execution plan

Use this phased plan to stand up CP-6(3) quickly without waiting for a full DR program refresh.

First 30 days (establish the control and identify gaps)

• Name the control owner and approver; document scope of alternate storage sites.
• Build the dependency map for each site (physical, network, identity, third party).
• Produce the initial failure-mode list and prioritize by plausibility and impact.
• Draft the risk-to-mitigation matrix and open work items for top gaps.
• Create an evidence checklist and repository folder structure.

By 60 days (implement high-value mitigations + run a tabletop)

• Implement no-regret mitigations: updated runbooks, emergency contacts, break-glass access procedure, alternate restore connectivity option where feasible.
• Validate third party contracts have operational escalation paths and access terms documented.
• Run a tabletop exercise for an area-wide disruption scenario; capture action items and owners.
• Start exception tracking for anything that requires longer engineering lead time.

By 90 days (prove operability with a degraded-access test)

• Execute a restore test that stresses accessibility (for example, restore without the primary network path or with a simulated identity dependency outage).
• Close or re-plan the highest-risk gaps uncovered in testing.
• Finalize the CP-6(3) control narrative and ensure evidence is assessment-ready.
• Add CP-6(3) checks to change management triggers for storage/network/identity changes.

Frequently Asked Questions

What counts as an “alternate storage site” for CP-6(3)?

Any location or service where you store backup copies intended for recovery qualifies, including cloud storage accounts/regions, tape vaults, and managed backup repositories. If recovery depends on it, include it in scope ¹.

Do we have to use a second region or second provider to meet CP-6(3)?

CP-6(3) does not mandate a specific architecture; it requires you to identify accessibility problems and document explicit mitigations ¹. A second region/provider is a common mitigation when regional disruption is a credible blocker.

How do we document “explicit mitigation actions” in an auditor-friendly way?

Use a risk-to-mitigation matrix with named owners, triggers, and links to runbooks or tickets. Avoid generic statements; each mitigation should be independently verifiable ¹.

We use a third party for backups. Can we inherit CP-6(3) from them?

You can rely on third party capabilities, but you still need your own analysis of accessibility problems and documented actions you will take if that third party or region is impaired ¹. Keep contracts, escalation paths, and test evidence that your restore process works.

What evidence is most commonly missing during assessments?

Teams often lack a written accessibility problem analysis and a record of tests that simulate degraded access. A DR plan alone rarely shows CP-6(3)-specific work ¹.

How should we handle exceptions where mitigations are planned but not implemented?

Record the failure mode, the planned mitigation, interim compensating controls, an accountable owner, and a target completion trigger tied to your risk process. Auditors look for managed risk, not silent gaps.

Footnotes

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

2. NIST SP 800-53 Rev. 5