ISO 27001 A.8.17: clock synchronization, explained for startups
What A.8.17 asks of a small company, and what an auditor samples.
Keep the clocks on your systems in sync with a trusted time source. Consistent timestamps make logs line up during investigations.
Why it exists: to line up the times in its logs so events can be traced.
A.8.17 Clock synchronization
All systems use the same trusted clock, so logs line up. What proves it: systems set to a trusted time source.
A certification auditor samples time source configuration. A file that usually does the job: host configuration, or provider documentation showing that a trusted time service is used.
How to put it in place
Each step leaves a record, and the record is what the auditor samples rather than the step itself. Inside Polara, the control card for A.8.17 walks you through it in this order.
- Confirm servers and containers use your cloud provider's time service or a trusted Network Time Protocol (NTP) server.
- Make sure laptops set their time automatically.
- Record the setting.
The free ISO 27001 readiness assessment asks one question that evidences it:
- Are system clocks synchronized?
Policies, connectors and the SOC 2 overlap
In the ISO 27001 policy pack, the Logging and Monitoring Policy covers A.8.17. An auditor reads the policy for the rule, then samples the records to see the rule was followed.
The same evidence counts toward SOC 2. The Trust Services criterion that cover this ground: CC7.2, anomaly monitoring.
Technological controls
A.8.17 is one of the 34 technological controls in Annex A. The controls built into your systems: access, devices, malware, vulnerabilities, backups, logging, networks, encryption and secure development. Exports and settings screenshots prove most of them.
Nearby controls in the same theme:
- A.8.14, redundancy
- A.8.15, logging
- A.8.16, monitoring for anomalies
- A.8.18, powerful admin utilities
- A.8.19, installing software
- A.8.20, network security
Before it: A.8.16, monitoring for anomalies. After it: A.8.18, powerful admin utilities. Every control, by theme, is on the Annex A controls page.
Questions
What does ISO 27001 A.8.17 require?
What evidence does an auditor want for A.8.17?
Get ready for ISO 27001 certification.
The readiness assessment is free, with no payment and no card. ISO 27001 is part of Constellation, at $10,800 a year: everything in Orbit plus the management system, the policies, the evidence and the management review for ISO 27001, and your SOC 2 Type 2 audit is included in every contract year. You contract the certification body directly.
The internal audit is priced separately: Polara arranges it with an independent internal auditor from our partner network who works in the platform, and quotes it for your company.
Take the free assessmentPolara Labs is not a certification body. Certification audits are performed by independent accredited certification bodies.