Windows Defender AV must be configured to check for definition updates daily.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75245	WNDF-AV-000030	SV-89925r2_rule		Medium

Description
This policy setting allows you to specify the day of the week on which to check for definition updates. The check 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 (default) (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never If you enable this setting the check for definition updates will occur at the frequency specified. If you disable or do not configure this setting the check for definition updates will occur at a default frequency.

Description

This policy setting allows you to specify the day of the week on which to check for definition updates. The check 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 (default) (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never If you enable this setting the check for definition updates will occur at the frequency specified. If you disable or do not configure this setting the check for definition updates will occur at a default frequency.

STIG	Date
MS Windows Defender Antivirus Security Technical Implementation Guide	2020-05-12

Details

Check Text ( C-75037r3_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Specify the day of the week to check for definition updates" is set to "Enabled" and "Every Day" is selected in the drop down box. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Signature Update Criteria: If the value "ScheduleDay" is REG_DWORD = 0, this is not a finding.

Check Text ( C-75037r3_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Specify the day of the week to check for definition updates" is set to "Enabled" and "Every Day" is selected in the drop down box.

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

Criteria: If the value "ScheduleDay" is REG_DWORD = 0, this is not a finding.

Fix Text (F-81855r3_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Signature Updates -> "Specify the day of the week to check for definition updates" to "Enabled" and select "Every Day" in the drop down box.