PR.DS-01: The confidentiality, integrity, and availability of data-at-rest are protected

PR.DS-01 requires you to protect the confidentiality, integrity, and availability of data stored on disks, databases, backups, endpoints, and removable media. Operationalize it by classifying stored data, encrypting it with managed keys, restricting and monitoring access, hardening storage platforms, validating backup/restore, and retaining evidence that controls run continuously (NIST CSWP 29).

Key takeaways:

• Treat “data-at-rest” broadly: production, backups, logs, endpoints, and snapshots all count (NIST CSWP 29).
• Auditors look for provable control operation: encryption status, key management, access reviews, and restore tests, not policy statements.
• Assign a control owner and build recurring evidence collection so you can defend PR.DS-01 on demand (NIST CSF 1.1 to 2.0 Core Transition Changes).

The target keyword for this page is pr.ds-01: the confidentiality, integrity, and availability of data-at-rest are protected requirement. For a CCO or GRC lead, PR.DS-01 is straightforward in wording and easy to miss in execution: it covers every place data is stored, including “secondary” storage that lives outside your core application stack (backups, exported reports, developer laptops, SaaS attachments, and analytic extracts).

This requirement sits at the intersection of security engineering and compliance operations. Security teams can encrypt databases and call it “done,” while auditors will still flag gaps if keys are unmanaged, backups are untested, access is overbroad, or integrity controls are informal. Availability is the other common miss: you can protect confidentiality and integrity and still fail PR.DS-01 if ransomware or accidental deletion can take stored data offline without a verified recovery path.

Your goal is to make PR.DS-01 defensible. That means clear scope, clear control ownership, an implementation standard teams can follow, and evidence you can produce quickly. The guidance below is written so you can assign actions, set expectations with IT and engineering, and pass an exam without improvising.

Regulatory text

Requirement (excerpt): “The confidentiality, integrity, and availability of data-at-rest are protected” (NIST CSWP 29; NIST CSF 1.1 to 2.0 Core Transition Changes).

Operator interpretation: You must implement technical and procedural controls that (1) prevent unauthorized reading of stored data (confidentiality), (2) prevent or detect unauthorized/accidental modification of stored data (integrity), and (3) keep stored data accessible and recoverable when needed (availability). “Data-at-rest” includes data on servers, databases, file shares, endpoints, cloud object storage, snapshots, and backups (NIST CSWP 29).

Plain-English interpretation (what you’re being held to)

PR.DS-01 is satisfied when you can show all three outcomes across all in-scope storage locations:

• Confidentiality: Stored sensitive data is encrypted or otherwise protected from unauthorized disclosure, and access is least privilege.
• Integrity: You can detect or prevent unauthorized changes to stored data through controls like access controls, immutability/WORM where appropriate, checksums, logging, and change governance.
• Availability: You can restore stored data and access it within business needs, even after incidents like ransomware, misconfiguration, or deletion.

A policy that says “we encrypt data at rest” is not enough. You need evidence that encryption is actually enabled, keys are protected, access is controlled, and recovery is tested (NIST CSWP 29).

Who it applies to (entity and operational context)

Applies to: Any organization running a cybersecurity program and adopting NIST CSF 2.0 practices, especially those storing regulated, confidential, or mission-critical data (NIST CSWP 29).

Operational scope to include (typical):

• Cloud storage (object/block/file), managed databases, data warehouses, and SaaS storage where you control configuration
• On-prem storage arrays, file shares, NAS/SAN, virtual disks
• Endpoints and mobile devices storing corporate data
• Backups, snapshots, archives, and exported reports
• Logs containing sensitive data (app logs, audit logs, security logs)

Third-party dependency note: Even if data is stored by a third party (SaaS, managed hosting), PR.DS-01 still translates into due diligence and configuration assurance. You may “inherit” some controls, but you still own governance, risk decisions, and evidence.

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

Use this sequence to operationalize quickly and avoid the common trap of addressing only encryption.

1) Define “data-at-rest” scope and classify data

1. Inventory storage locations that contain organizational data (include backups and endpoints).
2. Classify data types stored in each location (public, internal, confidential, regulated).
3. Document which systems are in scope for PR.DS-01 and who owns each system.

Output: Data-at-rest scope register (system → data type → owner → storage type).

2) Set minimum security standards for stored data

Establish a written standard (one page is fine) that states:

• Encryption requirements by data classification
• Key management expectations (ownership, rotation approach, separation of duties)
• Access control baseline (least privilege, MFA for admin paths where applicable)
• Backup and restore expectations (including protection from tampering)

Tie the standard to PR.DS-01 so it is auditable (NIST CSWP 29).

3) Implement confidentiality controls (encryption + access)

1. Enable encryption-at-rest on databases, file systems, object stores, and managed services where available.
2. Ensure encryption coverage for backups, snapshots, and replicas.
3. Centralize key management where feasible; document who can administer keys and how access is approved.
4. Restrict access to stored data:
   • Minimize administrators with direct read access
   • Separate duties: storage admins should not automatically be data readers
   • Require approvals and ticketing for privileged access

Exam-ready test: Pick one critical dataset and trace it through production storage and backups. Confirm encryption and access controls exist at each hop.

4) Implement integrity controls (prevent/detect tampering)

1. Enable immutable or write-once protections for backups and archives where your threat model includes ransomware.
2. Enforce change control for storage configurations (encryption settings, replication policies, lifecycle rules).
3. Turn on audit logging for access and administrative actions on storage platforms; retain logs per your retention policy.
4. Establish a process to review high-risk changes (key policy edits, disabling encryption, changing bucket policies).

Integrity is where teams often under-document. Auditors want to see how you would detect unauthorized modification and how you prevent silent drift.

5) Implement availability controls (recoverability, not promises)

1. Define recovery expectations for critical datasets (what must be restorable and by whom).
2. Ensure backups exist, are protected, and are not trivially erasable by the same identities that can modify production.
3. Run restore tests and record outcomes, issues, and remediation actions.
4. Confirm storage resiliency settings (replication, snapshots) align with business needs.

Availability evidence almost always carries more weight than architectural diagrams.

6) Assign control ownership and recurring evidence collection

PR.DS-01 fails in audits when it is “everyone’s job,” meaning nobody owns evidence. Assign:

• A control owner (typically Security, IT, or Cloud Platform)
• System owners accountable for configuration compliance
• A cadence for collecting evidence (monthly/quarterly, aligned to your control schedule)

This maps directly to NIST CSF implementation discipline: policy, procedure, owner, and recurring evidence (NIST CSF 1.1 to 2.0 Core Transition Changes; NIST CSWP 29).

Where Daydream fits: Daydream is useful here as the operating layer to map PR.DS-01 to owners, procedures, and evidence requests, then track recurring collection so you can answer audits without rebuilding proof each cycle.

Required evidence and artifacts to retain

Keep artifacts that prove design and operation:

Governance

• Data classification standard and data-at-rest protection standard mapped to PR.DS-01
• Scope register (systems/storage locations in scope, owners, data types)
• RACI (control owner, system owners, approvers)

Technical evidence (samples are fine if scoped and justified)

• Screenshots/exports showing encryption-at-rest enabled for representative systems
• Key management configuration evidence (key policies, access lists, administrative role assignments)
• Access control evidence: role/group membership, privileged access approvals, periodic access reviews
• Audit logging configuration and sample log entries for storage admin events
• Backup configuration and immutability/WORM settings where applicable
• Restore test records (tickets, runbooks, logs, post-test notes)

Operational

• Procedures/runbooks: enabling encryption, key access requests, backup/restore, incident recovery steps
• Exceptions register: any system not encrypted, why, compensating controls, risk acceptance, expiration date

Common exam/audit questions and hangups

Use these as a readiness checklist:

• “Show me all systems where sensitive data is stored and confirm encryption-at-rest is enabled.”
• “Are backups encrypted and protected from deletion or tampering by normal administrators?”
• “Who can access encryption keys? How is that access approved and reviewed?”
• “How do you detect unauthorized changes to stored data or storage policies?”
• “Prove you can restore critical data. Show the latest restore test and remediation.”

Hangup pattern: Teams produce a policy and a cloud architecture diagram, but cannot produce configuration evidence or restore test records.

Frequent implementation mistakes and how to avoid them

1. Encrypting only production databases.
   Fix: include snapshots, replicas, exports, logs, and backups in scope and evidence.

2. Key management as an afterthought.
   Fix: document who can administer keys, require approvals, and separate key admins from routine data readers.

3. Overreliance on “the cloud provider handles it.”
   Fix: identify what you inherit versus what you configure, and retain third-party assurance plus your tenant configuration evidence.

4. No integrity story.
   Fix: enable audit logging for storage admin actions, use immutability for backups where relevant, and document change control for storage policies.

5. No restore proof.
   Fix: run restore tests, record results, and track follow-ups. Treat failures as findings with owners and due dates.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so this page does not cite specific actions or penalties.

From a risk standpoint, PR.DS-01 maps to common incident failure modes: exposed storage, stolen backups, insider access misuse, ransomware encryption of stored data, and data corruption that goes undetected until recovery is needed. Examiners focus on whether your controls would have reduced the likelihood or impact of those events and whether you can prove controls operated as designed (NIST CSWP 29).

Practical 30/60/90-day execution plan

Use time horizons as operational phases. Adapt to your control calendar and audit dates.

First 30 days (stabilize scope and minimum controls)

• Name the PR.DS-01 control owner and define in-scope systems and storage locations.
• Publish a data-at-rest protection standard mapped to PR.DS-01 (encryption, keys, access, backups).
• Triage high-risk gaps: unencrypted storage holding confidential data, publicly exposed buckets/shares, unknown backup status.
• Set up an evidence pack structure (folders or GRC system) and start collecting configuration proof.

Days 31–60 (close core gaps and make it auditable)

• Roll out encryption-at-rest across in-scope platforms; document exceptions with compensating controls and approvals.
• Implement or tighten key management access controls and approvals; produce an access list and review record.
• Turn on storage audit logging and route logs to your logging platform; validate you can retrieve events.
• Define and approve backup/restore procedures for critical datasets.

Days 61–90 (prove availability and integrity; harden operations)

• Execute restore tests for representative critical datasets; log results and remediation.
• Add immutability/WORM controls for backups where your threat model warrants it; document design decisions.
• Formalize recurring evidence collection (scheduled exports/screenshots, access review cadence, restore test schedule).
• Run a lightweight internal audit: pick one dataset and trace it through storage, backup, access, keys, and restore proof.

Frequently Asked Questions

Does PR.DS-01 require encryption-at-rest everywhere?

The requirement is outcome-based: confidentiality, integrity, and availability of stored data must be protected (NIST CSWP 29). In practice, encryption-at-rest is the default control for confidentiality; if you don’t encrypt a store, document the exception and compensating controls.

What counts as “data-at-rest” for SaaS and third parties?

Any organizational data stored by a third party is still “data-at-rest” from your risk perspective. Treat it as shared responsibility: collect third-party assurance and also retain evidence of your tenant-side configuration (access controls, export controls, retention settings).

How do I prove integrity for stored data without building custom hashing for everything?

Start with controls that prevent and detect tampering: least-privilege access, administrative audit logs for storage platforms, change control on storage policies, and immutability for backups where appropriate. Auditors usually accept platform-native integrity controls if they are configured and evidenced.

What evidence is most persuasive to auditors?

Configuration evidence (encryption enabled, key policies, access lists), restore test records, and audit log samples are usually more persuasive than narrative documents. Keep a scoped sample set and document why it represents the full population.

How do we handle legacy systems that can’t encrypt at rest?

Put them in an exceptions register with business justification, compensating controls (segmentation, strict access, monitoring), and an exit plan. Tie the exception to a named risk owner and review it on a defined cadence.

Where does Daydream help with PR.DS-01?

Daydream helps you operationalize the control by mapping PR.DS-01 to owners, procedures, and recurring evidence requests, then tracking collection and exceptions. That reduces audit fire drills and makes control operation visible across teams.