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V-8557

The Windows Time Service on the forest root PDC Emulator must be configured to acquire its time from an external time source.

Finding ID
AD.0295
Rule ID
SV-9054r2_rule
Severity
Cat II
CCE
(None)
Group Title
Time Synchronization-Authoritative Source
CCI
CCI-001891
Target Key
(None)
Documentable
No
Discussion

When the Windows Time service is used to synchronize time on client computers (workstations and servers) throughout an AD forest, the forest root domain PDC Emulator is the normal default to provide the authoritative time source for the entire forest. To obtain an accurate time for itself, the forest root domain PDC Emulator acts as a client to an external time source. If the Windows Time service on the forest root domain PDC Emulator is not configured to acquire the time from a proper source, it may cause time service clients throughout the forest to operate with the inaccurate time setting. When a Windows computer operates with an inaccurate time setting, access to resources on computers with the accurate time might be denied. This is notably true when Kerberos authentication is utilized. Operation with an inaccurate time setting can reduce the value of audit data and invalidate it as a source of forensic evidence in an incident investigation. Further Policy Details: The Windows Time service is the preferred time synchronization tool for Windows domain controllers. This check is Not Applicable for Component locations that do not have the AD forest root domain on site. This check must be performed on the domain controller in the *forest root domain* that holds the PDC Emulator FSMO role.

Fix Text

Configure the Windows Time service on the forest root PDC Emulator to acquire its time from an external time source.

Check Content

1. Use Registry Editor to navigate to the following: HLM\System\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient 2. If the value for “Enabled” is not “1”, then this is a finding. 3. Use Registry Editor to navigate to the following: HKLM\System\CurrentControlSet\Services\W32Time\Parameters 4. If the value for “Type” is not “NTP”, then this is a finding. Note: If these checks indicate a finding because the NtpClient is not enabled, ask the SA to demonstrate that a) an alternate time synchronization tool is installed and enabled and that b) a DoD-authorized external time source is being used. 5. If the Windows Time service is not enabled or no alternate tool is installed and enabled in its place, then this is a finding.

Responsibility

Information Assurance Officer

IA Controls

ECTM-1, ECTM-2