NIST SP 800-53 Rev. 5 AU-3(3) — Limit Personally Identifiable Information Elements

What this control requires

Limits PII in audit records to elements identified in privacy risk assessments, reducing privacy risks when PII is not needed for operations. This control supports the PII Filtering Module capability within the Audit and Accountability family.

In plain English

Limits PII in audit records to elements identified in privacy risk assessments, reducing privacy risks when PII is not needed for operations. In practice, this means you can prove you policy management-level controls on a defined cadence.

Why it matters

SP 800-53 is the catalogue every U.S. federal authorisation (FedRAMP, FISMA, CMMC) and most regulated industries point at. A missing control surfaces as a Plan of Action & Milestones (POA&M) item that an Authorizing Official must approve before the Authority To Operate is granted or renewed.

This control is rated high. Auditors expect a named owner, a remediation SLA, and a tooling artefact that evidences continuous operation.

What an auditor looks for

A 3PAO (FedRAMP) or Independent Assessor (NIST RMF) tests against NIST SP 800-53A assessment procedures. For each control they expect a documented implementation that addresses every assessment objective (Examine, Interview, Test) and an implementation summary in the System Security Plan.

Within Audit and Accountability, the assessor will trace your implementation back to the catalogue reference (Control AU-3(3)) and look for objective evidence on the latest two assessment cycles.

How to implement

Logging Monitoring

AWS. Org-trail CloudTrail to a central log archive account, GuardDuty in every region, and Security Hub for cross-source correlation.

Azure. Pipe every diagnostic setting into a central Log Analytics workspace; onboard Microsoft Sentinel for SIEM/SOAR.

GCP. Aggregate audit logs in a dedicated logging project with sink to BigQuery; enable Security Command Center Premium and route findings to Chronicle SIEM.

Policy Management

Docs. Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA.

Operational checklist

• Policy. Document the trigger, the owner and the cadence.
• Audit. Document the trigger, the owner and the cadence.
• Information. Document the trigger, the owner and the cadence.
• Data. Document the trigger, the owner and the cadence.
• Protection. Document the trigger, the owner and the cadence.
• Scope: management, information, privacy, personally identifiable information, records, audit records, personally identifiable information elements, protection.

Evidence to collect

• Policy Document. A signed and version-controlled policy / standard / procedure document.

Signed policy or standard documents the safeguard. Focus: Limit Personally Identifiable Information Elements.

Common pitfalls

• Per-account logging that nobody stitches together at the org level — incidents that cross accounts go undetected for days.
• Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• SOC 2 (2017 TSC) P2.1 — Communication of Data Subject Choices and Consequences
• NIST SP 800-171 Rev. 3 3.3.8 — Protection of Audit Information

Related controls in NIST SP 800-53 Rev. 5

• Control AU-16(3) — Disassociability
• Control SI-12(1) — Limit Personally Identifiable Information Elements
• Control AU-3 — Content Of Audit Records
• Control SI-18(1) — Automation Support
• Control SI-19 — De-Identification
• Control SI-19(2) — Archiving

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control AU-3(3)

Topics: governance riskdata protectionprivacy managementlogging monitoringpolicy management