Protect stored account data

To meet the protect stored account data requirement in PCI DSS 4.0, you must (1) minimize what account data you store, and (2) apply controls that prevent unauthorized access to any account data that must remain at rest. Operationalize it by completing a data inventory, setting retention rules, enforcing strong access controls, and documenting encryption and key management for every storage location ¹.

Key takeaways:

• Store the minimum account data needed, for the shortest time, and prove it with a retention standard plus deletion evidence ¹.
• Treat every repository as in-scope until you can show it contains no account data ¹.
• Auditors will ask you to trace controls from “where data lives” to “who can access it” to “how it’s protected” with artifacts, not narratives ¹.

“Protect stored account data” is a storage governance requirement, not a single encryption checkbox. Under PCI DSS 4.0, the expectation is straightforward: if you store account data, you control how long it stays, where it can exist, and how it is protected from unauthorized access ¹.

For a CCO, GRC lead, or compliance operator, the hard part is rarely the policy statement. The work is building a defensible operational system across payment applications, databases, logs, analytics platforms, file shares, endpoints, backups, and third parties that may receive or store account data. You need an inventory that does not lie, retention limits that engineering can implement, and technical controls that hold up under testing.

This page gives requirement-level implementation guidance you can run as a short program: identify all stored account data, reduce it aggressively, lock down what remains, and produce audit-ready evidence that the controls operate consistently. The language below stays anchored to the PCI DSS 4.0 baseline excerpt: limit storage and protect stored account data from unauthorized access ¹.

Regulatory text

PCI DSS 4.0 (PCI-08) excerpt: “Limit storage and protect stored account data from unauthorized access.” ¹

Operator interpretation (plain English)

• “Limit storage” means you set explicit rules for what account data is allowed to be stored, where it may be stored, and how long it may remain. If a team cannot justify storage, the default is deletion and prevention of re-creation ¹.
• “Protect stored account data from unauthorized access” means that any repository that stores account data must have technical and administrative controls that prevent access by unauthorized users and systems, and you must be able to show those controls are operating ¹.

A practical test: if an auditor asks, “Show me all places account data is stored and how each is protected,” you can answer with an inventory and a mapped control set, then produce evidence from systems of record.

Who it applies to (entity and operational context)

Entities: Merchants and service providers that store account data in any form ¹.

Operational context (common in-scope storage locations):

• Payment application databases (orders, subscriptions, recurring billing tokens plus any related data)
• Data warehouses and analytics extracts
• Application logs and APM traces that might capture PAN-like values
• Ticketing systems and attachments (support, disputes, chargebacks)
• File shares, SFTP drops, and exports emailed between teams
• Backups, snapshots, DR replicas, and long-term archives
• End-user endpoints where exports are opened or saved
• Third parties that receive data feeds or host systems that store account data

If you cannot prove a system does not store account data, treat it as potentially in scope until proven otherwise.

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

Step 1: Establish the scope with a “stored account data” inventory

Create a living inventory that answers:

• What data elements are stored (be precise: “account data” in PCI terms can appear in structured fields, free text, logs, or attachments)
• Where it is stored (system, environment, database/table/bucket, backup targets)
• Why it is stored (business justification)
• Who/what can access it (roles, service accounts, third parties)
• How it is protected (access controls, encryption, key management, monitoring)

Practical approach:

• Start with payment flows and work outward (app → DB → logs → exports → backups → analytics).
• Add “shadow IT” discovery: shared drives, ad hoc reporting databases, and support tooling.

Artifact to produce: Stored Account Data Inventory (owner, last review date, repository list, data elements, retention, protection method).

Step 2: Set and enforce retention limits (“limit storage”)

You need a written retention standard that engineering can implement:

• Allowed data elements to store vs prohibited elements
• Approved storage locations
• Retention periods by data type and system (business-driven, defensible)
• Deletion and purge mechanisms (automated where possible)
• Exceptions process (who approves, how exceptions expire)

Operationalize the policy:

• Implement automated deletion jobs for databases and object stores.
• Update log configuration to avoid capturing sensitive values; add masking/redaction at ingestion where feasible.
• Ensure backups/snapshots respect the same retention logic, or document compensating controls.

Evidence to retain:

• Data retention policy/standard specific to account data storage ¹.
• System configs or job definitions for purge processes.
• Execution evidence: logs of deletion jobs, lifecycle policies, or change tickets.

Step 3: Protect what remains with layered technical controls

For each storage repository that still contains account data, implement controls in four layers:

1. Access control (prevent unauthorized access)

• Role-based access tied to job function
• Separate duties for administrators vs analysts
• Strong authentication for privileged access
• Tight controls on service accounts (scoped permissions; no shared credentials)

2. Encryption at rest

• Encrypt storage volumes, database fields/columns as needed, and object stores
• Define encryption standards (algorithms, modes) in your security standard
• Ensure encryption keys are protected and access is restricted

3. Key management and custody

• Define key ownership, rotation procedures, and access approvals
• Control who can decrypt (limit key access to a small admin set)
• Centralize key management where feasible (HSM/KMS), or document the design where not

4. Monitoring and change control

• Alert on unusual access patterns to repositories with account data
• Track and approve changes to encryption settings, retention configurations, and access policies

Day-to-day operator tip: A repository with encryption enabled but broad read permissions is a frequent failure mode. Auditors read “protect from unauthorized access” literally.

Step 4: Prevent re-introduction of stored account data

Once you reduce storage, you must keep it reduced:

• Add DLP-style checks or scanning for account-number patterns in logs, file stores, and ticket attachments.
• Gate new exports and integrations through an intake process that asks, “Does it store account data? Where? For how long?”
• Require engineering reviews for schema changes that introduce new sensitive fields.

Step 5: Document controls in an audit-traceable way

Turn the above into a control narrative plus mapping:

• For each repository in the inventory, map: retention rule + access control + encryption + key management owner.
• Document exception handling and review cadence.

If you use Daydream to manage PCI evidence, set up a single requirement workspace for the protect stored account data requirement, attach the inventory, retention standard, encryption/key management standards, and link each system’s proof artifacts to reduce scramble during assessment.

Required evidence and artifacts to retain

Keep evidence in a form an assessor can validate without interpretive effort:

Governance

• Stored Account Data Inventory (versioned; owner; last review)
• Data retention standard for stored account data ¹
• Encryption and key management standard covering stored account data

Technical configurations

• Screenshots/exports of encryption settings per storage service (DB, storage buckets, volumes)
• Key management configuration evidence (KMS policies, key access lists)
• Access control evidence (role assignments, group membership, IAM policies)

Operational proof

• Data purge job logs / lifecycle policy execution evidence
• Tickets/approvals for exceptions and access grants
• Evidence of periodic review of stored account data locations and access

Common exam/audit questions and hangups

Use this as your pre-audit checklist:

1. “Show me where account data is stored.”
   Hangup: teams provide a diagram, not a repository list. Provide the inventory with system-level detail.

2. “Why do you store it, and for how long?”
   Hangup: “because the app does” is not a justification. Tie retention to a business purpose and show deletion controls ¹.

3. “How do you prevent unauthorized access?”
   Hangup: encryption is offered as the only answer. Provide access control evidence plus encryption and key custody ¹.

4. “Do backups contain the same data? Are they protected and retained appropriately?”
   Hangup: backups are out of mind. Add backup targets to inventory and show retention and access controls.

5. “How do you ensure logs and tickets don’t store account data?”
   Hangup: teams assume “we don’t log that.” Show logging configs, masking rules, and scans.

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails	What to do instead
Writing a retention policy but not implementing deletion	Auditors test operation, not intent	Implement purge automation and keep execution logs
Ignoring non-database storage (logs, tickets, attachments)	Sensitive values appear in “unstructured” places	Scan and redact; restrict attachments; add prevention checks
Encrypting at rest but allowing broad read access	Unauthorized access can still occur via valid credentials	Tighten RBAC, reduce groups, require approvals and MFA for privileged access
Forgetting backups/snapshots	They preserve deleted data and expand scope	Apply lifecycle rules; restrict restore permissions; document retention
Key access is too broad	Anyone who can decrypt effectively has access	Limit KMS/HSM permissions; review key access regularly

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement. You should still treat this as a real risk control: stored account data increases breach impact, extends incident response scope, and raises assessment scrutiny because assessors can validate storage and protection through sampling and configuration review ¹.

Practical 30/60/90-day execution plan

First 30 days: Get to an honest inventory and stop new storage

• Assign an owner (security or GRC) and system owners per repository.
• Build the Stored Account Data Inventory with initial discovery across prod systems, logs, exports, and backups.
• Implement a change gate: any new data store or export must declare whether it stores account data and how it will be protected.
• Draft the retention standard for stored account data and circulate it for engineering sign-off ¹.

Days 31–60: Reduce storage and harden access

• Remove account data from non-essential locations (analytics extracts, old file shares, legacy exports).
• Implement purge automation per system and validate outcomes with before/after samples.
• Tighten access controls: least privilege roles, approval workflow, service account scoping.
• Enable encryption at rest where missing; document exceptions and compensating controls.

Days 61–90: Prove operations and get assessment-ready

• Add scanning/monitoring for re-introduction (log redaction validation, periodic repository scans).
• Conduct an internal control test: pick repositories at random and verify retention, access control, encryption, and key access evidence.
• Package evidence in an audit-ready format (inventory + standards + per-system proof). If you use Daydream, link artifacts directly to the requirement so the evidence set stays current between assessments.

Frequently Asked Questions

Do we fail the protect stored account data requirement if we store account data at all?

No. PCI DSS 4.0 requires you to limit storage and protect stored account data from unauthorized access ¹. Your job is to justify storage, minimize it, and prove protection and retention controls operate.

Does “stored account data” include logs and support tickets?

Treat them as in scope if they can contain account data in text fields or attachments. Build controls to prevent capture (masking/redaction), restrict access, and apply retention limits consistent with your standard ¹.

Is encryption at rest enough to satisfy “protect stored account data”?

Encryption is part of protection, but the requirement is protection from unauthorized access ¹. Assessors commonly expect tight access controls plus key management that limits who can decrypt.

How should we handle backups that contain account data?

Add backups, snapshots, and archives to your inventory and apply retention and access controls. Control restore permissions tightly and document lifecycle settings and evidence of operation.

What evidence is most persuasive to an auditor?

A repository-level inventory mapped to controls, plus system-generated proof: IAM policies/role assignments, encryption settings, KMS/HSM access lists, and deletion job logs. Avoid relying on policy statements without operating evidence.

How can we keep this from becoming a quarterly fire drill?

Make the inventory a living asset: tie it to change management, require updates when systems change, and schedule periodic owner attestations. Tools like Daydream help by keeping artifacts and control mappings in one place so evidence doesn’t decay between assessments.

Related compliance topics

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

Footnotes

1. PCI DSS v4.0, PCI DSS Document Library