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Hardware Write-once Media

LOW MODERATE HIGH
1 Overlay 2 Related Controls
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Requirements NIST SOURCE

Write audit trails to hardware-enforced, write-once media.

Discussion (NIST Supplemental Guidance)

Writing audit trails to hardware-enforced, write-once media applies to the initial generation of audit trails (i.e., the collection of audit records that represents the information to be used for detection, analysis, and reporting purposes) and to the backup of those audit trails. Writing audit trails to hardware-enforced, write-once media does not apply to the initial generation of audit records prior to being written to an audit trail. Write-once, read-many (WORM) media includes Compact Disc-Recordable (CD-R), Blu-Ray Disc Recordable (BD-R), and Digital Versatile Disc-Recordable (DVD-R). In contrast, the use of switchable write-protection media, such as tape cartridges, Universal Serial Bus (USB) drives, Compact Disc Re-Writeable (CD-RW), and Digital Versatile Disc-Read Write (DVD-RW) results in write-protected but not write-once media.

Implementation Guidance

Engineering Interpretation

Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.

No engineering interpretation has been authored for AU-9(1) yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.

Assessment

NIST SP 800-53A REV 5.2.0

Assessment Objectives

  1. audit trails are written to hardware-enforced, write-once media.

Examine

[SELECT FROM: Audit and accountability policy; system security plan; privacy plan; access control policy and procedures; procedures addressing protection of audit information; system design documentation; system hardware settings; system configuration settings and associated documentation; system storage media; system audit records; other relevant documents or records].

Interview

[SELECT FROM: Organizational personnel with audit and accountability responsibilities; organizational personnel with information security and privacy responsibilities; system/network administrators; system developers].

Test

[SELECT FROM: System media storing audit trails].

Overlays

Showing the OT/ICS overlay for the parent control AU-9 — see the AU-9(1) entries within each baseline below.

OT/ICS Overlay SP 800-82r3

NIST SP 800-82r3 Appendix F, Table 22. Blank baseline means the control/control enhancement is not selected in that initial OT baseline.

LOW

  • Base control: Included (matches standard baseline)

MODERATE

  • Base control: Included (matches standard baseline)
  • Included: (4)

HIGH

  • Base control: Included (matches standard baseline)
  • Included: (2) (3) (4)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for AU-9(1). This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.

Learn more about STIG/CCI integration →

Evidence

Potential Evidence — Derived

Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.

Policy

  • Audit and accountability policy
  • system security plan
  • privacy plan
  • access control policy and procedures

Configuration

  • system design documentation
  • system configuration settings and associated documentation

Testing

  • System media storing audit trails

Other Records

  • procedures addressing protection of audit information
  • system hardware settings
  • system storage media
  • system audit records
  • other relevant documents or records