SV-278659r1192819: Microsoft Defender AV must randomize scheduled task times. | Microsoft Defender Antivirus STIG SCAP Benchmark

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Assessment Title

Rule Text

Microsoft Defender AV must randomize scheduled task times.

Description

Discussion Text

In Microsoft Defender Antivirus, randomize the start time of the scan to any interval from 0 to 23 hours. By default, scheduled tasks begin at a random time within four hours of the time specified in Task Scheduler.

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

IA Controls

NIST SP 800-53

Not mappedCCI-002624

References

DPMS Target Microsoft Defender Antivirus DISA DPMS Target Microsoft Defender Antivirus 3985

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.windowsdefav:def:278659
# Microsoft Defender AV must randomize scheduled task times.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Verifies 'Randomize scheduled task times' is 'Enabled'
# registry_object (registry_test)
function test_1 {
  return (((@{String='reg_sz';ExpandString='reg_expand_sz';Binary='reg_binary';DWord='reg_dword';MultiString='reg_multi_sz';QWord='reg_qword';None='reg_none'}[(Get-Item -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender').GetValueKind('RandomizeScheduleTaskTimes').ToString()]) -eq 'reg_dword') -and (((Get-ItemProperty -Path 'Registry::HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender' -Name 'RandomizeScheduleTaskTimes' -ErrorAction SilentlyContinue) | Select-Object -ExpandProperty 'RandomizeScheduleTaskTimes') -eq 1))
}

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_defender_antivirus target this check assesses.

# OVAL Definition: oval:mil.disa.stig.windowsdefav:def:278659
$regPath = "HKLM\SOFTWARE\Policies\Microsoft\Windows Defender"
$regKey = "RandomizeScheduleTaskTimes"
$expectedValue = 1
if (Test-Path $regPath -ErrorAction SilentlyContinue) {
    $regValue = Get-ItemProperty -Path $regPath -Name $regKey -ErrorAction SilentlyContinue
    if ($regValue -and $regValue.$regKey -eq $expectedValue) {
        Write-Output "PASS"; exit 0
    }
}
Write-Output "FAIL"; exit 1

Remediation

Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Randomize scheduled task times to "Enabled".