Browse 1,193 controls and enhancements across 20 security and privacy families. Use the GovRAMP crosswalk to locate controls referenced by Security Snapshot, Core, and Moderate.
A shared catalog supports common-control planning; designation as a common, hybrid, or system-specific control depends on your organization’s implementation and inheritance decisions.
Sources and crosswalk scope
NIST OSCAL content 5.1.1+u4, retrieved 2026-09-18. GovRAMP Snapshot v1.4 and Core selection from Moderate v1.06 reference the December 2020 Rev. 5 text. Mappings establish exact identifier correspondence, not identical requirements, inherited implementation, or GovRAMP authorization. GovRAMP parameters and additional requirements remain authoritative for each program. Full Moderate, High, and other programs are not mapped here. Withdrawn controls are retained for reference.
System and Communications Protection · Base control
SC-45 · System Time Synchronization
Control statement and discussion
NIST control statement
Synchronize system clocks within and between systems and system components.
Discussion
Time synchronization of system clocks is essential for the correct execution of many system services, including identification and authentication processes that involve certificates and time-of-day restrictions as part of access control. Denial of service or failure to deny expired credentials may result without properly synchronized clocks within and between systems and system components. 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. The granularity of time measurements refers to the degree of synchronization between system clocks and reference clocks, such as clocks synchronizing within hundreds of milliseconds or tens of milliseconds. Organizations may define different time granularities for system components. Time service can be critical to other security capabilities—such as access control and identification and authentication—depending on the nature of the mechanisms used to support the capabilities.
GovRAMP crosswalk
GovRAMP Moderate Readiness · SC-45 — Direct NIST identifier reference. GovRAMP source matrix
System and Communications Protection · Enhancement
SC-45(1) · Synchronization with Authoritative Time Source
(a) Compare the internal system clocks [Assignment: frequency] with [Assignment: authoritative time source] ; and
(b) Synchronize the internal system clocks to the authoritative time source when the time difference is greater than [Assignment: time period].
Discussion
Synchronization of internal system clocks with an authoritative source provides uniformity of time stamps for systems with multiple system clocks and systems connected over a network.
GovRAMP crosswalk
GovRAMP Moderate Readiness · SC-45 (1) — Direct NIST identifier reference. GovRAMP source matrix
System and Communications Protection · Enhancement
(a) Identify a secondary authoritative time source that is in a different geographic region than the primary authoritative time source; and
(b) Synchronize the internal system clocks to the secondary authoritative time source if the primary authoritative time source is unavailable.
Discussion
It may be necessary to employ geolocation information to determine that the secondary authoritative time source is in a different geographic region.
GovRAMP crosswalk
Not selected in the imported Snapshot or Core sets. This does not establish exclusion from other GovRAMP baselines.
