Windows Defender AV must be configured to perform a weekly scheduled scan.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75237	WNDF-AV-000026	SV-89917r2_rule		Medium

Description
This policy setting allows you to specify the day of the week on which to perform a scheduled scan. The scan can also be configured to run every day or to never run at all. This setting can be configured with the following ordinal number values: (0x0) Every Day (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never (default) If you enable this setting a scheduled scan will run at the frequency specified. If you disable or do not configure this setting a scheduled scan will run at a default frequency.

Description

This policy setting allows you to specify the day of the week on which to perform a scheduled scan. The scan can also be configured to run every day or to never run at all. This setting can be configured with the following ordinal number values: (0x0) Every Day (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never (default) If you enable this setting a scheduled scan will run at the frequency specified. If you disable or do not configure this setting a scheduled scan will run at a default frequency.

STIG	Date
Windows Defender Antivirus Security Technical Implementation Guide	2017-12-27

Details

Check Text ( C-75029r3_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Specify the day of the week to run a scheduled scan" is set to "Enabled" and anything other than "Never" selected in the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Scan Criteria: If the value "ScheduleDay" is REG_DWORD = 0x8, this is a finding. Values of 0x0 through 0x7 are acceptable and not a finding.

Check Text ( C-75029r3_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Specify the day of the week to run a scheduled scan" is set to "Enabled" and anything other than "Never" selected in the drop down box.

Procedure: Use the Windows Registry Editor to navigate to the following key:
HKLM\Software\Policies\Microsoft\Windows Defender\Scan

Criteria: If the value "ScheduleDay" is REG_DWORD = 0x8, this is a finding.

Values of 0x0 through 0x7 are acceptable and not a finding.

Fix Text (F-81847r2_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Scan -> "Specify the day of the week to run a scheduled scan" to "Enabled " and select anything other than "Never" in the drop down box.