PT-7(1): Social Security Numbers

To meet the pt-7(1): social security numbers requirement, you must treat Social Security numbers (SSNs) as high-risk personal data and put explicit, testable handling rules around collection, use, display, storage, transmission, sharing, and disposal whenever any system processes SSNs. Operationalize it by inventorying SSN processing, minimizing it, restricting access, protecting it technically, and keeping assessor-ready evidence. ¹

Key takeaways:

• You need an SSN-specific data flow inventory and documented rules for when SSNs are permitted.
• Minimize SSN processing and enforce least privilege plus strong technical protections everywhere SSNs appear.
• Evidence matters as much as design: produce repeatable artifacts that prove SSN controls operate as intended.

PT-7(1) sits in the NIST SP 800-53 privacy control family and is triggered any time a system processes SSNs. The practical goal is simple: if SSNs enter your environment, you should be able to answer, quickly and confidently, “Where are SSNs, why do we have them, who can access them, how are they protected, and how do we prove it?” ²

For a CCO or GRC lead, the fastest path is to treat this as a requirement you can “package” into an assessable control: assign an owner, document the procedure, implement technical guardrails (data discovery, masking, encryption, access controls, logging), and retain recurring evidence. The most common failure mode is not malicious handling; it’s uncontrolled SSN sprawl across tickets, spreadsheets, logs, test data, and third-party integrations, followed by thin documentation that cannot survive an audit interview.

This page gives requirement-level implementation guidance you can put into production: applicability, step-by-step execution, evidence to retain, audit questions, common mistakes, and a practical 30/60/90-day plan.

Regulatory text

Excerpt (as provided): “When a system processes Social Security numbers:” ¹

Operator interpretation: PT-7(1) is a conditional requirement. The moment SSNs are processed by a system (collected, stored, transmitted, used to make decisions, displayed, exported, or shared), you must implement explicit controls for SSN handling and be able to demonstrate those controls to assessors. Treat this as an SSN processing standard plus proof that the standard is enforced. ¹

Plain-English interpretation

If SSNs exist anywhere in a system’s lifecycle, you must:

1. Know where SSNs are and why they’re there.
2. Reduce SSN processing to only what is necessary and authorized.
3. Protect SSNs from unauthorized access or disclosure.
4. Control how SSNs are displayed, shared, and disposed.
5. Maintain evidence that these controls are implemented and operating.
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Who it applies to

Entity scope

• Federal information systems and contractor systems handling federal data implementing NIST SP 800-53 controls. ¹

Operational scope (what “processes SSNs” means in practice)

Treat PT-7(1) as in-scope if SSNs appear in any of the following:

• Enrollment/onboarding workflows (HR, benefits, identity proofing)
• Customer or citizen service intake
• Background checks or eligibility determinations
• Data warehouses/lakes, BI exports, analytics notebooks
• Scanned documents, attachments, case management notes
• Support tooling (tickets, chat transcripts), email, collaboration platforms
• Logs/telemetry if application events capture SSNs
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If a third party processes SSNs on your behalf, you still need governance: contract terms, access boundaries, and evidence that the third party’s processing is controlled and monitored within your third-party risk program.

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

Use this as an implementation runbook you can assign to control owners.

Step 1: Name the control owner and write the “SSN handling standard”

Deliverable: “SSN Handling Standard” (1–3 pages) that answers:

• Approved business purposes for SSN collection/processing
• Prohibited uses (examples: using SSN as a general identifier when alternatives exist)
• Where SSNs may be stored (approved systems) and may not be stored (non-approved tools)
• Display rules (masking/truncation standards; who can view full SSN)
• Sharing rules (internal sharing, third-party sharing, export restrictions)
• Disposal rules (retention triggers, deletion/destruction method)
• Exception process (who approves, time-bound exceptions, compensating controls)
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Operational tip: Keep the standard actionable and testable. Auditors will ask, “Show me how you enforce that statement.”

Step 2: Build an SSN data inventory and data-flow map

Goal: enumerate every system, table/bucket, document store, and integration where SSNs exist or could appear.

Minimum fields for the inventory:

• System/application name and owner
• Data elements (full SSN, last-4, hashed, tokenized)
• Purpose/legal basis (your internal authority and business justification)
• Storage locations (including backups and archives)
• Data entry points (forms, imports, API endpoints, batch feeds)
• Recipients (internal teams, third parties)
• Retention requirement and deletion mechanism
• Security controls in place (access model, encryption, masking, logging)
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How to execute quickly:

• Run targeted data discovery for SSN patterns across structured and unstructured stores.
• Review top export pathways: SFTP drops, reporting extracts, ad hoc analyst queries.
• Validate with SMEs: HR, Finance, Identity, Benefits, Case Management, Security Operations.

Step 3: Minimize SSN processing

Minimization is your best risk reducer and simplest audit story.

Controls to implement:

• Replace SSN as a primary key with a system-generated identifier.
• Store last-4 only where full SSN is not required for the business purpose.
• Tokenize or vault full SSNs and keep applications on tokens.
• Block SSNs from free-text fields when feasible (form validation, DLP patterns).
• Keep SSNs out of lower environments (dev/test) unless a documented exception exists.
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Decision rule: If the process can complete without full SSN, do not collect or store full SSN.

Step 4: Restrict access (least privilege) and harden authentication paths

What assessors look for is clarity: “Who can see full SSNs, and why?”

Implement:

• Role-based access control with explicit “view full SSN” permission.
• Segregate duties for bulk export/reporting of SSNs (separate roles or approvals).
• Strong authentication for privileged roles and sensitive workflows.
• Periodic access reviews focused on SSN-capable roles and service accounts.
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Step 5: Protect SSNs in storage, transmission, and display

Your standard should translate into technical enforcement:

• Encryption for SSN-bearing data stores and backups, with controlled key access.
• TLS for SSN transmission paths (APIs, file transfer).
• Masking/truncation in UI and reports by default; “reveal full SSN” requires elevated privilege and is logged.
• Redaction in attachments, generated PDFs, and outbound correspondence templates.
• DLP rules for email/collaboration and endpoints where feasible in your environment.
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Step 6: Detect and respond to SSN exposure

PT-7(1) becomes real during incidents. Build operating muscle:

• Log access to full SSN fields and bulk exports.
• Alert on anomalous access (new role assignments, high-volume reads, unusual export jobs).
• Maintain an incident playbook branch for “SSN exposure,” including containment and third-party notifications where applicable.
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Step 7: Control third-party processing

If a third party receives or processes SSNs:

• Contractually define permitted purposes, security requirements, and breach notification terms.
• Require data minimization (only fields needed) and restrict onward transfer.
• Confirm secure transfer method and destination controls.
• Keep an integration-level data sharing register tied to the SSN inventory.
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Step 8: Make it assessable (map to owner, procedure, recurring evidence)

A common gap is “we do this” without a repeatable evidence set. Build a control record that includes:

• Control owner
• Implementation procedure
• Evidence list and collection cadence
• Known exceptions and risk acceptance workflow
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Daydream fits naturally here as the system of record to map PT-7(1) to an accountable owner, document the procedure, and schedule recurring evidence requests so audits stop being scavenger hunts. ¹

Required evidence and artifacts to retain

Keep artifacts that prove both design and operation:

Governance artifacts

• SSN Handling Standard (approved, versioned)
• Data classification standard showing SSN sensitivity tier
• Exception register for SSN processing (approvals, expiration, compensating controls)
• Third-party data sharing register entries for SSN transfers
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Technical artifacts

• Data discovery scan outputs or reports showing where SSNs were detected
• Screenshots or config exports showing masking rules and field-level permissions
• Encryption configuration evidence (storage encryption settings; key access controls)
• DLP policies (pattern definitions, enforcement mode, incident queue samples)
• Logging configuration demonstrating SSN access is logged and retained
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Operational artifacts (ongoing)

• Access review attestations for SSN-capable roles and service accounts
• Sample audit logs showing SSN access events and export events
• Ticket/change records showing remediation of newly discovered SSN locations
• Incident exercises or post-incident reports involving SSN exposure scenarios (if applicable)
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Common exam/audit questions and hangups

Assessors tend to drill into “show me” proof. Prepare tight answers to:

1. Where are SSNs stored and processed? Provide the inventory and data-flow map. ¹
2. Why do you need SSNs at all? Show documented business purpose, minimization decisions, and alternatives evaluated. ¹
3. Who can see full SSNs? Show role definitions, least-privilege rationale, and access review results. ¹
4. How do you prevent SSNs from ending up in logs/tickets/spreadsheets? Show technical controls (validation, DLP) and detection scans. ¹
5. How do you know controls are operating? Show recurring evidence and monitoring outputs. ¹

Hangup to expect: teams often document encryption generally, but cannot demonstrate field-level exposure control (masking + privileged reveal + logging). Build that trail.

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails in audits	Fix
“We don’t store SSNs” stated without evidence	Discovery scans or exports contradict the claim	Run discovery, document results, and remediate findings; keep scan reports. 1
SSNs in non-approved tools (tickets, email, chat, spreadsheets)	Uncontrolled access and retention	Add DLP + user guidance + intake form controls; route SSNs into approved systems only. 1
Full SSN visible by default in UI	Overexposure to broad user base	Mask by default; “reveal full SSN” requires permission and is logged. 1
Test environments populated with real SSNs	Lower environments often have weaker controls	Enforce synthetic data; restrict and time-box exceptions with compensating controls. 1
Third-party sharing handled informally	No proof of permitted purpose or boundaries	Add integration-specific SSN transfer records; contract clauses; periodic review. 1

Enforcement context and risk implications

No public enforcement case sources are provided in the source catalog for this requirement, so this page does not list specific cases. ¹

Risk still concentrates in predictable areas:

• Breach impact: SSNs are persistent identifiers. Exposure tends to drive high incident response cost and downstream harm for individuals.
• Operational risk: SSN sprawl makes incident scope determination slow and error-prone.
• Assessment risk: the easiest PT-7(1) finding is “no evidence,” even when teams believe controls exist. ¹

Practical 30/60/90-day execution plan

Use this as a sprint plan for a CCO/GRC lead coordinating Security, IT, and system owners.

First 30 days (stabilize and locate)

• Assign a PT-7(1) control owner and identify systems likely to process SSNs. ¹
• Publish an interim SSN handling rule: approved systems, “no SSNs in tickets/email,” and default masking expectation. ¹
• Start SSN discovery scans across priority repositories (data warehouse, document stores, ticketing, shared drives). ¹
• Stand up an evidence checklist and repository, and begin capturing configs and screenshots as you go. ¹

Days 31–60 (minimize and control)

• Complete the SSN inventory and data-flow maps for in-scope systems. ¹
• Implement masking by default in key apps and reports; restrict “view full SSN” to specific roles. ¹
• Reduce SSN retention and remove SSNs from non-approved tools; track remediation tickets to closure. ¹
• Add monitoring: logs for SSN field access and bulk export events, plus alerting paths. ¹

Days 61–90 (prove operation and make it repeatable)

• Run an access review for SSN-capable roles and service accounts; document approvals and removals. ¹
• Test incident response for an SSN exposure scenario and capture lessons learned. ¹
• Finalize the SSN Handling Standard, exception workflow, and recurring evidence calendar. ¹
• In Daydream, map PT-7(1) to the owner, procedure, and recurring artifacts so evidence collection survives staff turnover. ¹

Frequently Asked Questions

Does PT-7(1) apply if we only store last-4 SSN?

Treat last-4 as in-scope if it can still identify an individual in your context or is processed as an SSN-derived identifier. Document what you store (full vs last-4), why, and how display/access differs. ¹

What counts as “processing” an SSN for this requirement?

Processing includes collecting, storing, transmitting, displaying, exporting, or using SSNs in decisions or matching logic. If SSNs appear in logs, tickets, attachments, or analytics, you are processing them. ¹

How do we prove we don’t have SSNs in unstructured tools like email or ticketing?

Keep outputs from SSN discovery scans, DLP policy configurations, and remediation tickets that show detected SSNs were removed and controls were put in place to prevent recurrence. Evidence beats assertions. ¹

What should we do if a third party needs SSNs for a business process?

Record the transfer in your SSN data-flow map, minimize fields shared, restrict permitted purpose contractually, and confirm secure transfer and access controls. Keep the contract language and integration diagrams as evidence. ¹

Is encryption alone enough to satisfy PT-7(1)?

No. Encryption addresses confidentiality at rest and in transit, but assessors also expect minimization, access restriction, masking, monitoring, and evidence that the rules are enforced in day-to-day operations. ¹

What evidence is most likely to be missing during an assessment?

Teams often lack a single SSN inventory/data-flow map and a repeatable evidence set for access reviews, masking enforcement, and detection of SSNs in non-approved repositories. Build those first. ¹

Footnotes

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

2. NIST SP 800-53 Rev. 5