SC-7(24): Personally Identifiable Information

To meet the sc-7(24): personally identifiable information requirement, you must identify every system boundary where PII crosses (ingress, egress, and internal segmentation) and implement boundary protections that prevent unauthorized disclosure or exfiltration. Operationally, that means mapping PII data flows, enforcing policy at network and application boundaries, and retaining assessor-ready evidence that the protections run continuously ¹.

Key takeaways:

• Scope first: you cannot implement SC-7(24) until you know which systems process PII and where PII traverses trust boundaries ².
• Build boundary controls around PII flows: restrict, inspect, log, and validate transfers of PII across boundaries ³.
• Evidence is a deliverable: define a control owner, procedure, and recurring artifacts so you can prove the control operates, not just that it exists ³.

SC-7 is the NIST SP 800-53 “Boundary Protection” control family, and enhancement (24) narrows attention to a specific high-risk data class: personally identifiable information (PII). The excerpt you have for SC-7(24) is short, but the operational expectation is not. If a system processes PII, you are expected to treat PII movements across boundaries as a first-class security and compliance concern, then demonstrate that your boundary protections actually cover those movements ¹.

For a CCO or GRC lead, the fastest path is to translate SC-7(24) into an implementable requirement statement: “We know where PII enters, exits, and traverses between trust zones, and we enforce and monitor controls at those boundaries to prevent unauthorized transfer.” Then you assign ownership, write a procedure that your engineers can execute, and design evidence that an auditor can verify without reverse-engineering your environment. This page gives you the requirement-level interpretation, a practical implementation playbook, and an evidence checklist tailored to assessment reality ².

Regulatory text

Provided excerpt (verbatim): “For systems that process personally identifiable information:” ³

What the operator must do with this text Because the excerpt flags applicability (“systems that process PII”), your first compliance obligation is scoping: determine which systems are in-scope for SC-7(24) because they process PII ². Your second obligation is operational: implement boundary protections specifically for PII-processing systems and be able to show those protections align to real PII flows ³.

Practical reading for operators:

• If the system stores, transmits, or transforms PII, treat it as in-scope.
• “Boundary” means wherever trust changes: Internet edge, third-party connections, inter-VPC/VNet, prod-to-nonprod, app-to-app APIs, and admin access paths.
• The control is not satisfied by a generic firewall diagram. You need PII-aware boundaries: controls selected and tuned because the data is PII, with monitoring and evidence ².

Plain-English interpretation (what SC-7(24) requires)

For any system that processes PII, you need to prevent unauthorized disclosure by controlling how PII crosses system boundaries. In practice, auditors expect you to: (1) know where PII flows, (2) restrict those flows to approved paths, (3) monitor boundary events, and (4) prove the control works over time with repeatable artifacts ¹.

If you can’t answer “where does PII enter/leave this system?” you are not ready to claim SC-7(24) is implemented.

Who it applies to (entity and operational context)

Organizations

• Federal information systems.
• Contractor systems handling federal data where NIST SP 800-53 is contractually required or inherited through an authorization boundary ².

Systems and environments

• Applications that collect PII (customer onboarding, HR systems, case management).
• Data platforms where PII lands (data lake/warehouse, analytics pipelines).
• Identity, CRM, support tooling, and integrations that transport PII to third parties.
• Hybrid networks where PII traverses on-prem to cloud or cloud-to-cloud links ².

Operational trigger The moment your system processes PII, SC-7(24) becomes a boundary-protection requirement, not a privacy-policy exercise ³.

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

Use this sequence to operationalize sc-7(24): personally identifiable information requirement quickly and cleanly.

1) Define “PII” for scoping and evidence

• Publish a PII data definition and examples relevant to your business (names, government identifiers, account identifiers, contact data, employee data).
• Align the definition to your data classification standard so engineering teams can tag fields and stores consistently ².

Deliverable: PII definition + data classification mapping referenced by security architecture docs.

2) Identify in-scope systems and owners

• Inventory systems that store, process, or transmit PII.
• Assign a control owner per system boundary (often Security Engineering/Network Engineering) and a business owner for PII processing accountability ³.

Deliverable: System list with owners, boundary diagram links, and “processes PII: yes/no” rationale.

3) Map PII data flows across trust boundaries

For each in-scope system, document:

• Entry points (web forms, APIs, batch imports).
• Exits (reports, exports, notifications, third-party APIs, SFTP, email gateways).
• Internal boundary crossings (microservices, message buses, cross-account or cross-subscription traffic, admin planes) ².

Deliverable: PII data flow diagrams or tables that show source → destination → protocol → authentication method → encryption method → logging point.

4) Define the “approved paths” for PII movement

Translate your flow map into enforceable rules:

• Allowed sources/destinations (by network segment, service identity, or endpoint).
• Approved protocols (for example, HTTPS/TLS-based APIs instead of ad-hoc file transfers).
• Approved third parties and integration points ².

Deliverable: Boundary policy for PII flows (human-readable) plus corresponding technical rule sets (machine-enforceable).

5) Implement boundary protections mapped to each PII flow

Pick control mechanisms appropriate to your architecture; common patterns include:

• Network controls: security groups, firewalls, network segmentation, egress controls.
• Application controls: API gateways, authentication/authorization enforcement, schema validation for PII-bearing payloads.
• Data loss controls at boundary: outbound filtering and blocking where feasible, plus alerting on anomalous exfiltration paths.
• Strong logging at boundary: capture allow/deny, identity context, and destination metadata ².

Implementation check: Every PII flow in your map should have (a) a control point and (b) a log source.

6) Instrument detection and response for boundary events involving PII

• Route boundary logs to a central log platform/SIEM.
• Create alert logic for disallowed destinations, unusual volumes, failed policy checks, and administrative changes to boundary rules.
• Tie alerts to incident response runbooks that explicitly mention PII handling and escalation paths ².

Deliverable: Monitoring coverage statement + alert catalog + incident workflow references.

7) Operationalize: recurring review and change control

• Require security review for changes that introduce new PII flows or modify egress paths.
• Update the PII flow map when onboarding a new third party integration, new API, or new data export ³.

Deliverable: Change management evidence showing boundary rule updates were reviewed and approved.

8) Package the control for assessment: owner, procedure, evidence

NIST-aligned programs often fail here. The simplest durable approach (and the only “recommended control” provided in your data pack) is:

• Map SC-7(24) to a named control owner.
• Write an implementation procedure engineers can follow.
• Define recurring evidence artifacts you can produce on demand ³.

If you run Daydream as your GRC system of record, configure SC-7(24) as a requirement with (1) accountable owner, (2) linked procedures, and (3) evidence tasks that collect artifacts on a predictable cadence. That turns “we have boundary controls” into “we can prove it quickly.”

Required evidence and artifacts to retain

Auditors will ask for proof that your boundary protections cover PII-processing systems. Retain:

1. Scope and system selection

• In-scope system inventory with “processes PII” determination ².
• Data classification/PII definition reference.

2. Architecture and data flow

• Current network/system boundary diagrams for each in-scope system.
• PII data flow map that identifies each boundary crossing ².

3. Control design

• Boundary policy for PII flows (approved paths, allowed endpoints, permitted protocols).
• Standards for segmentation, egress control, and logging requirements ².

4. Control operation (the evidence most teams miss)

• Configuration exports or screenshots for firewall/security group/egress policies tied to named systems.
• API gateway policies, authZ rules, or service-to-service access policies for PII endpoints.
• Logging evidence: sample logs showing allow/deny events and identity context at boundaries.
• Alert definitions and recent alert history (even if benign) showing monitoring runs ³.

5. Governance

• Control owner assignment and responsibility matrix.
• Change tickets showing approvals for boundary rule changes affecting PII flows.
• Exception register for any non-standard PII transfer paths and compensating controls ².

Common exam/audit questions and hangups

Expect these questions, and prepare “show me” answers:

• “Which systems process PII, and how do you know?” Bring the system inventory and your PII definition mapping ².
• “Show me where PII crosses your boundary.” Provide one data flow map per in-scope system and trace a real example transaction ².
• “Where is the control point for this flow?” Point to the specific firewall rule, gateway policy, or egress allowlist covering that flow.
• “How do you detect policy violations?” Show alert logic and evidence it is live ².
• “How do you ensure changes don’t create new, unapproved PII paths?” Show change control steps and recent tickets.

Hangup to plan for: assessors may reject a “generic boundary protection” narrative if you cannot tie it to PII-specific flows. Keep the mapping explicit.

Frequent implementation mistakes (and how to avoid them)

1. Mistake: Scoping PII systems by intuition.
   Fix: Require a documented “PII present” determination for each system, backed by data stores/fields or interface descriptions ².

2. Mistake: Diagram-only compliance.
   Fix: Pair diagrams with enforceable rules and configuration evidence that matches the diagram.

3. Mistake: Forgetting egress.
   Fix: Treat outbound paths (exports, third-party APIs, email, logging sinks) as primary boundary risk for PII.

4. Mistake: No operational evidence.
   Fix: Pre-define recurring artifacts (config exports, sample logs, alert tests, ticket samples) and collect them continuously ³.

5. Mistake: Shadow integrations.
   Fix: Gate new third party integrations through architecture review that includes “does this move PII across a boundary?”

Enforcement context and risk implications

No public enforcement cases are provided in your source catalog for SC-7(24), so you should treat this as an assessment-readiness and breach-risk requirement rather than mapping to a specific penalty outcome ³. The practical risk is straightforward: undocumented or uncontrolled PII egress paths are hard to monitor and easy to misuse, and they complicate incident response because you cannot quickly determine what left the boundary and how.

A practical 30/60/90-day execution plan

First 30 days (stabilize scope and ownership)

• Publish your PII definition and scope rules for “system processes PII.”
• Build the in-scope system list and assign control owners.
• For the highest-risk system, produce a PII data flow map and identify all boundary crossings ².

By 60 days (implement enforceable boundaries for priority flows)

• Formalize approved PII transfer paths (policy + technical standards).
• Implement or tighten egress restrictions for priority systems (Internet, third-party connections, cross-network links).
• Centralize boundary logging and stand up first-pass alerts tied to PII flows ².

By 90 days (make it repeatable and auditable)

• Expand flow maps and boundary control mappings across remaining in-scope systems.
• Add change control checks for new PII flows and new third party integrations.
• Stand up an evidence routine: periodic config exports, log samples, and alert validation captured in your GRC workflow ³.

Daydream fit: this is the point where teams either keep evidence in scattered folders or convert it into a managed requirement with assigned owners and recurring evidence tasks. Daydream supports the second path by making SC-7(24) evidence collection predictable instead of heroic.

Frequently Asked Questions

Does SC-7(24) apply if we only transmit PII and don’t store it?

Yes, if your system processes PII, transmission counts as processing for scoping. Treat transmission boundaries (APIs, file transfers, third-party connections) as in-scope and control them ².

What’s the minimum documentation an assessor will accept for “PII flows”?

A table can work if it clearly shows source, destination, protocol, control point, and logging point for each PII flow. The key is traceability from a PII flow to an enforced boundary control ².

We use SaaS tools that handle PII. Is SC-7(24) relevant to third parties?

Yes. The boundary often becomes your integration point to the third party (API, SSO, data export). Document the PII flows into the third party and the controls and approvals around that connection ².

Does encryption alone satisfy SC-7(24)?

Encryption reduces exposure in transit, but SC-7(24) is a boundary protection expectation, so you still need allowed paths, access controls, and monitoring at the boundary. Show how encryption fits into a broader boundary control design ².

How do we handle exceptions, like a legacy PII export process?

Track an explicit exception with scope, business justification, compensating controls, and an owner and review workflow. Keep evidence that the exception is approved and monitored ².

What evidence is most likely to fail an audit for SC-7(24)?

Teams often fail on operational proof: no config exports tied to PII flows, no log samples, and no evidence that alerts are active. Treat evidence artifacts as required deliverables, not optional attachments ³.

Footnotes

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

2. NIST SP 800-53 Rev. 5

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