NIST SP 800-53 Rev. 5 AU-9(6) — Read-Only Access

What this control requires

Authorizes read-only access to audit information for a defined subset of privileged users or roles to limit potential damage from unauthorized modifications. This control supports the Access Control System capability within the Audit and Accountability family.

In plain English

Authorizes read-only access to audit information for a defined subset of privileged users or roles to limit potential damage from unauthorized modifications. In practice, this means you can prove you access 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.

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-9(6)) 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.

Operational checklist

• Access. 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.
• Review. Document the trigger, the owner and the cadence.
• Access Control. Document the trigger, the owner and the cadence.
• Scope: management, access control, information, system, only, audit information, identity, review.

Evidence to collect

• Identity Scan. IAM / IdP exports — Entra ID, Okta, IAM Identity Center, Workspace directory — showing accounts, roles, MFA state and last sign-in.

Identity analytics (Okta, SailPoint, Access Analyzer) demonstrates least-privilege. Focus: Read-Only Access.

Common pitfalls

• Per-account logging that nobody stitches together at the org level — incidents that cross accounts go undetected for days.

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.

• NIST SP 800-171 Rev. 3 3.3.8 — Protection of Audit Information
• CIS Controls v8 6.7 — Centralize Access Control
• ISO/IEC 27001:2022 A.8.2 — Privileged access rights
• BSI C5:2020 PS-04 — Physical site access control
• SOC 2 (2017 TSC) CC6.2 — Access Provisioning

Related controls in NIST SP 800-53 Rev. 5

• Control AU-9(4) — Access By Subset Of Privileged Users
• Control AU-10(1) — Association Of Identities
• Control AU-6(7) — Permitted Actions
• Control AC-6(2) — Non-Privileged Access For Nonsecurity Functions
• Control AU-16(1) — Identity Preservation
• Control AU-16(2) — Sharing Of Audit Information

References

• NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5
• Catalogue identifier: Control AU-9(6)

Topics: identity accessprivileged accessidentity managementaccess reviewlogging monitoring