SV-205706r1051075: Windows Server 2019 computer clock synchronization tolerance must be limited to five minutes or less. | Microsoft Windows Server 2019 STIG SCAP Benchmark

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Assessment Title

Rule Text

Windows Server 2019 computer clock synchronization tolerance must be limited to five minutes or less.

Description

Discussion Text

This setting determines the maximum time difference (in minutes) that Kerberos will tolerate between the time on a client's clock and the time on a server's clock while still considering the two clocks synchronous. To prevent replay attacks, Kerberos uses timestamps as part of its protocol definition. For timestamps to work properly, the clocks of the client and the server need to be in sync as much as possible. Satisfies: SRG-OS-000112-GPOS-00057, SRG-OS-000113-GPOS-00058

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-001941Not mappedCCI-001942V-93451SV-103537

References

DPMS Target Microsoft Windows Server 2019 DISA DPMS Target Microsoft Windows Server 2019 2907

Checks

DISA STIG (Manual Reference)

This applies to domain controllers. It is NA for other systems.

Verify the following is configured in the Default Domain Policy:

Open "Group Policy Management".

Navigate to "Group Policy Objects" in the Domain being reviewed (Forest >> Domains >> Domain).
 
Right-click on the "Default Domain Policy".

Select "Edit".

Navigate to Computer Configuration >> Policies >> Windows Settings >> Security Settings >> Account Policies >> Kerberos Policy.

If the "Maximum tolerance for computer clock synchronization" is greater than "5" minutes, this is a finding.

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

# Windows PowerShell
# Reconstructed from oval:mil.disa.stig.windows2019:def:205706
# Windows Server 2019 computer clock synchronization tolerance must be limited to five minutes or less.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Kerberos Policy - Maximum tolerance for computer clock synchronization - 5 minutes or less
# wmi57_object (wmi57_test)
function test_1 {
  return (((Get-CimInstance -Namespace 'root\rsop\computer' -Query 'SELECT setting FROM RSOP_SecuritySettingNumeric WHERE KeyName=''MaxClockSkew''' | Select-Object -First 1) | Select-Object -ExpandProperty 'setting') -eq '5')
}

if (test_1) {
  Write-Output "PASS"
} else {
  Write-Output "FAIL"
}

Assessment Script Powered by AISyntax-verified

A standalone PowerShell script to assess this control automatically. Review before running it in your environment.

Syntax-checked as valid PowerShell. Not executed here — running it for real needs the actual ms_windows_server_2019 target this check assesses.

# OVAL Definition: oval:mil.disa.stig.windows2019:def:205706
$compliance = Get-CimInstance -ClassName RSOP_SecuritySettingNumeric -Namespace "root\rsop\computer" -Filter "KeyName='MaxClockSkew'"
if ($compliance -and $compliance.setting -le 5) { Write-Output "PASS"; Exit 0 } else { Write-Output "FAIL"; Exit 1 }

Remediation

Configure the policy value in the Default Domain Policy for Computer Configuration >> Windows Settings >> Security Settings >> Account Policies >> Kerberos Policy >> "Maximum tolerance for computer clock synchronization" to a maximum of "5" minutes or less.