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PL-2(2) Planning

Functional Architecture

High Risk Moderate Medium Cost

PL-2(2) (Functional Architecture) enhances base PL-2 within the NIST Planning family. Base PL-2 sets the foundational expectation; this enhancement adds specificity: This enhancement strengthens PL-2 with requirements for functional architecture in environments that create, receive, maintain, or transmit ePHI. Covered entities and business associates apply it to system security plans, rules of behavior, and security architecture for clinical systems holding ePHI.

Control Objective

Implement Functional Architecture so organization-defined planning safeguards operate consistently on systems and networks that handle ePHI, with measurable evidence for HIPAA and NIST assessments.

Implementation Guidance

  1. Map PL-2(2) to systems in scope (EHR, imaging, lab, pharmacy, billing, identity, backups, and BA connections).\n2. Translate “Functional Architecture” into technical settings, procedures, or architecture patterns owned by named roles.\n3. Prefer enforceable controls (config, automation, mediation) over awareness-only measures where feasible.\n4. Integrate with change, incident, and downtime processes so clinical operations are not surprised.\n5. Log and retain evidence of operation (tickets, configs, test results) aligned to audit needs.\n6. Include vendors/BAs in contracts and connection standards when they touch the control surface.\n7. Test after major EHR, network, or cloud changes — upgrades often reset protections.\n8. Review exceptions at least quarterly; expire “temporary” holes that expose ePHI paths.

Real-World Use Cases

How this control shows up in healthcare and HIPAA-covered environments.

Real-world scenario

EHR SSP CONOPS (PL-2(2))\nSystem security plan describes how charting, identity, and interfaces operate under PL-2 CONOPS. Evidence labeled for PL-2(2).\n\n### Coordinate with privacy (PL-2(2))\nSSP updates are coordinated with privacy and HIM when new ePHI data stores appear. Evidence labeled for PL-2(2).\n\n### Functional architecture diagram (PL-2(2))\nArchitecture appendix shows trust boundaries for patient portal, EHR, and claims systems. Evidence labeled for PL-2(2).

Best Practices

  • Name an owner for PL-2(2) in the SSP control matrix.\n- Favor system enforcement on ePHI paths over informal email approval.\n- Measure coverage: percent of in-scope clinical systems where the enhancement operates.\n- Review exceptions quarterly with security and clinical informatics.\n- Feed relevant events to SIEM with a named use case.\n- Keep a one-page evidence pack (config + sample log + last test) ready for assessors.

Common Gaps & Violations

  • Policy cites PL-2(2) but production EHR/network paths show no enforcement of functional architecture.\n- Permanent exceptions with no expiry for vendors or “special” clinics.\n- Control implemented only on corporate IT — clinical devices and interfaces omitted.\n- No logs or test records; reliance on tribal knowledge.\n- Major upgrade silently disabled the enhancement.

Required Documentation

  • Procedure/standard for Functional Architecture (PL-2(2))\n- Architecture or configuration baselines showing enforcement points\n- Exception register with owners and expiry\n- Sample logs, alerts, or test results\n- Training or runbook references for clinical/IT operators

How to Test & Validate

  1. Attempt a prohibited or out-of-policy action related to functional architecture; confirm block, alert, or required workflow.\n2. Complete an authorized clinical/IT path; confirm success and logging.\n3. Sample open exceptions for approval and expiry.\n4. Verify at least one EHR-adjacent and one BA/vendor path are in scope.\n5. Confirm evidence retained for the last 90 days (or per policy).

Audit Considerations

Assessors look for operating evidence of Functional Architecture on systems touching ePHI — configs, logs, restore/DR artifacts, or failed-test results — not only a policy paragraph referencing PL-2(2).

HIPAA Mapping

How this NIST control supports HIPAA Security Rule expectations.

  • 164.316(a) Policies and Procedures — implement reasonable and appropriate policies for ePHI safeguards.\n- 164.308(a)(1)(i) Security Management Process — plan security measures protecting ePHI.\n- 164.316(b)(1) Documentation — maintain written security plans and related records.\n- 164.306(a) Security standards — ensure CIA of ePHI through planned controls.

Compliance Tips

  • List PL-2(2) explicitly in the system security plan with system inventory references.\n- Prioritize emergency department, inpatient EHR, and remote access paths first.\n- Bundle evidence with related HIPAA evaluation, integrity, or workforce-security narratives where they overlap.

References & Resources

  • NIST SP 800-53 Rev. 5 — PL-2(2)\n- Related controls: PL-2, PL-8

Related Guidelines

Related controls that commonly accompany PL-2(2).

PL-2 Medium

System Security Plan

PL-2 requires developing system security and privacy plans that define the system boundary, operational environment…
PL-8 High

Information Security Architecture

PL-8 requires developing an information security architecture that describes how security requirements are allocated to system elements…
PL-1 Medium

Planning Policy and Procedures

PL-1 requires planning policy and procedures addressing purpose, scope, roles, management commitment, coordination, and compliance, plus…

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