ISO 27001:2022 · Technological controls
ISO 27001:2022 8.17: Clock synchronization
ISO 27001:2022 8.17 covers Clock synchronization . The held text names 5 evidence records for it, the first being Statement of Applicability entry for control A.8.17, showing inclusion or justified exclusion, implementation status and the risks it.... The common gap an assessor flags is Physical access and CCTV systems run on unsynchronized clocks, breaking correlation with IT logs.
The clocks of the organization's information processing systems are to be kept in step with approved time sources. Purpose (stated in ISO/IEC 27002:2022): enables correlation and analysis of security events and recorded data and supports incident investigations. As an Annex A reference control, it is compared with the controls determined in risk treatment (6.1.3 c) and recorded in the Statement of Applicability as included or excluded, with the justification and implementation status (6.1.3 d); implementation guidance is ISO/IEC 27002:2022 8.17.
What evidence supports 8.17?
- Annex A technological controlStatement of Applicability entry for control A.8.17, showing inclusion or justified exclusion, implementation status and the risks it treats
- Annex A technological controlDocumented time requirements (representation, accuracy, synchronization) and the defined organizational reference time
- Annex A technological controlNTP or PTP configuration showing systems synchronized to the approved reference clocks, including building management and physical access systems
- Annex A technological controlEvidence of a trusted reference source such as GPS or national time service, and use of two external sources where adopted
- Annex A technological controlMonitoring of clock drift across systems, with alerts on deviation
Where this requirement comes from
This is our own statement of ISO 27001:2022 8.17, read from the copy we hold (licensed complete copy) and stated in our words, not the standard verbatim. The framework as we hold it.
Common gaps an assessor flags
- Physical access and CCTV systems run on unsynchronized clocks, breaking correlation with IT logs
- Systems synchronize to arbitrary internet time servers not approved by the organization
- Time zones are mixed across logs without a standard representation
- Clock drift is not monitored, so failures of the time service go unnoticed
How it maps to SOC 2
No reviewed link is held for this control.
A link is a topical overlap with a confidence and a reason. It does not establish that meeting one requirement satisfies the other, and it is not certification.