What is ISO 27001:2022 Annex A 8.17 Clock synchronisation in ISO 27001?
ISO 27001 Annex A 8.17 ensures all clocks align across information systems. It is a documented process within your organisational tools. This control maintains log accuracy for forensic investigations. It prevents timestamps from becoming unreliable. Use SharePoint to store your time standards.
Auditor’s Eye: The Shortcut Trap
SaaS compliance platforms offer green ticks for NTP policies. These dashboards provide surface-level compliance only. They do not prove that your internal servers actually align. I prefer seeing configuration logs in your native SharePoint library. Jira tickets prove you investigate time drift actively. Relying on “Black Box” software decouples security from your infrastructure. Authentic evidence resides in your internal document repositories. This shows real management ownership.
| 2013 Control Reference | 2022 Control Reference | Nature of Change |
|---|---|---|
| Annex A 12.4.4 | Annex A 8.17 | Requirement renumbered but fundamentally unchanged. Focus remains on log integrity. |
How to Implement ISO 27001:2022 Annex A 8.17 (Step-by-Step)
Synchronise system clocks by integrating standards into your daily technical operations. Lead with a clear reference source in SharePoint. This ensures all logs remain accurate for incident response. Use your existing technical tools to maintain control.
- Select a reliable external time source like NTP.org.
- Document these sources in your SharePoint configuration library.
- Apply Group Policy Objects to sync all domain devices.
- Record server NTP settings in your internal Confluence wiki.
- Establish Jira alerts for synchronisation failures on critical servers.
- Log all drift remediation actions within Jira tickets.
ISO 27001:2022 Annex A 8.17 Audit Evidence Checklist
Auditors require manual records that prove continuous oversight. Your evidence must show intent and consistent management. Keep these files in your primary document management system.
- Version-controlled NTP configuration policy in SharePoint.
- Technical screenshots of NTP settings from core servers.
- Jira ticket history showing resolution of time drift alerts.
- Quarterly management review minutes discussing log integrity.
- Evidence of GPO deployment for workstation time sync.
Relational Mapping
Control A 8.17 connects to other ISO 27001 requirements:
- Annex A 8.16 (Monitoring): Accurate time is vital for log correlation.
- Annex A 5.24 (Incident Management): Timestamps enable chronological event mapping.
- Clause 8.1 (Operational Planning): Defines how time sync is maintained.
Auditor Interview
Auditor: How do you verify your systems share the same time?
Manager: We use an internal NTP server synced to NTP.org. Settings are documented in Confluence.
Auditor: Where can I see the history of synchronisation failures?
Manager: We track all NTP alerts in Jira. You can see the remediation steps in the ticket history.
Common Non-Conformities
| Failure Mode | Description | Corrective Action |
|---|---|---|
| Automated Complacency | Trusting a SaaS tick without local drift logs. | Move drift reviews to internal Jira workflows. |
| Conflicting Sources | Different servers syncing to different external sources. | Centralise reference time in the SharePoint policy. |
| Manual Overrides | Admins manually setting time on legacy systems. | Disable manual time changes via local policy. |
Frequently Asked Questions
What is the requirement for clock synchronisation in ISO 27001?
The Bottom Line Up Front: All system clocks must align with a single reference time source. This ensures log timestamps remain accurate for investigations. You must document this process in SharePoint. It prevents disputes over the timing of security events within your infrastructure.
How does an auditor verify clock synchronisation?
The Bottom Line Up Front: Auditors examine your internal configuration logs and NTP settings. They check Jira for records of synchronisation alerts. They look for management sign-off in meeting minutes. This proves your team actively manages time accuracy through your native repositories.
Why avoid SaaS platforms for NTP compliance?
The Bottom Line Up Front: SaaS tools provide surface level ticks but lack technical depth. They do not show if local server clocks actually match. Internal repositories like Confluence provide better forensic evidence. This keeps your security data integrated with daily technical operations.