ISO 27001A.8 — Networks security
A.8.20
Networks security
ISO 27001 · ISO/IEC 27001:2022 · Last verified July 2026
Objective
Secure networks and network devices to protect information in systems and applications.
Points of focus
- Define scope and requirements for networks security
- Assign ownership and operating cadence
- Integrate with risk treatment and SoA status
- Retain dated records proving operation
Implementation notes
Segment admin planes, restrict public exposure, and manage firewall / security-group changes under change control. Tie the SoA implementation summary to the systems of record engineers already use, and keep dated samples ready for Stage 2 sampling.
Audit tip: Present the SoA line for A.8.20, the current procedure, and one recent dated operating sample with a named owner.
Evidence auditors typically request:
- System configuration export or IaC policy screenshots
- Ticket samples with approver, date, and change outcome
- Monitoring or scan report covering the observation window
- Runbook or SOP linked from the SoA implementation summary
Common gaps
- SoA marks networks security applicable without dated operating samples
- Procedure exists but interviews describe a different tribal process
- Owner unclear or last review older than the stated cadence
Cross-Framework Mapping
| Framework | Requirement | Implementation note |
|---|---|---|
| ISO 27001 | A.8.20 | This control |
| SOC 2 | CC6.6, CC6.7 | Related Trust Services Criteria themes — map in your crosswalk; not identical requirements. |
Primary sources
- ISO/IEC 27001:2022 Annex A: ISO/IEC 27001:2022 Annex A (A.8.20)
Frequently Asked Questions
Applicability depends on risk and scope. Many cloud-native SoAs still include organizational and technological controls; physical themes may be partially inherited from providers with documented shared responsibility.
Applicability decision, brief implementation summary, and justification if excluded. Vague 'N/A — cloud' without rationale is a common Stage 1 finding.
Name the owner, the system of record, and the cadence. Auditors sample reality — tickets, configs, and interviews — not synonym-rewritten ISO text.