Checklist of ISO/IEC 27001-A.12.4.4 Clock synchronisation


The A.12.4.4 standard of ISO/IEC 27001 requires organizations to ensure that their system clocks are synchronized and accurate. 

This ensures that time-sensitive events are recorded accurately, and that systems across the organization are in sync with one another. 

This standard is essential to prevent security breaches and ensure operational efficiency. 

In this article, we will discuss the importance of clock synchronization, provide a sample checklist, and conclude with key takeaways.

Sample Checklist:

  • Is there a defined reference time based on atomic clocks such as GPS or NTP to a stratum 1 time reference?
  • Does the method for synchronizing clocks with the reference meet business, security, operational, legal, regulatory, and contractual requirements?
  • Has the synchronization method been implemented across the IT estate, including monitoring systems such as CCTVs, alerting and alarm systems, access control mechanisms, auditing and logging systems, IoT things, etc.?
  • Are monitoring arrangements in place to ensure the reference time is always available and accurate?
  • What happens if a time reference becomes unavailable? Are there alternative sources or failover mechanisms in place?
  • How are clock changes, leap seconds, and other time-related issues handled?
  • Have the associated information risks been analyzed and appropriately treated?


Ensuring clock synchronization is critical for maintaining accurate time-sensitive event recording and operational efficiency. 

The A.12.4.4 standard provides guidelines for organizations to synchronize their clocks, including the use of a defined reference time, appropriate synchronization methods, and monitoring arrangements. 

Organizations must ensure that clock synchronization is implemented across their IT estate and that associated information risks are analyzed and treated. 

See also  Cybersecurity Tips for Small/Medium Businesses

By following the sample checklist provided in this article, organizations can comply with the A.12.4.4 standard and maintain efficient operations.

Leave a comment

Your email address will not be published. Required fields are marked *