Device Class 1: Time Stamps

Control ID: AU-8 Time Stamps Family: Audit and Accountability Source: NIST 800-53r4
Control: The information system:
  1. Uses internal system clocks to generate time stamps for audit records; and
  2. Records time stamps for audit records that can be mapped to Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT) and meets [Assignment: organization-defined granularity of time measurement].
Supplemental Guidance:
Time stamps generated by the information system include date and time. Time is commonly expressed in Coordinated Universal Time (UTC), a modern continuation of Greenwich Mean Time (GMT), or local time with an offset from UTC. Granularity of time measurements refers to the degree of synchronization between information system clocks and reference clocks, for example, clocks synchronizing within hundreds of milliseconds or within tens of milliseconds. Organizations may define different time granularities for different system components. Time service can also be critical to other security capabilities such as access control and identification and authentication, depending on the nature of the mechanisms used to support those capabilities.

Related Controls: AU-3, AU-12
Control Enhancements:
(1) Time Stamps | Synchronization With Authoritative Time Source
The information system:
  1. Compares the internal information system clocks [Assignment: organization-defined frequency] with [A GPS-derived measure of UTC]; and
  2. Synchronizes the internal system clocks to the authoritative time source when the time difference is greater than [Assignment: organization-defined time period].

Supplemental Guidance: This control enhancement provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network.
Related Controls: N/A
References: N/A
Mechanisms:

  • The device shall support NTP and/or contain or have a means of synchronizing with a GPS receiver.

Protocol Implementation Conformance Statements:
ID Statement Status Reference Notes
AU-8/1 Supports NTP C1
AU-8/2 Provides alternative means of synchronizing with GPS receiver C1