Windows Defender AV must be configured to always enable real-time protection.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75227	WNDF-AV-000021	SV-89907r2_rule		Medium

Description
This policy setting turns off real-time protection prompts for known malware detection. Windows Defender Antivirus alerts you when malware or potentially unwanted software attempts to install itself or to run on your computer. If you enable this policy setting Windows Defender Antivirus will not prompt users to take actions on malware detections. If you disable or do not configure this policy setting Windows Defender Antivirus will prompt users to take actions on malware detections.

Description

This policy setting turns off real-time protection prompts for known malware detection. Windows Defender Antivirus alerts you when malware or potentially unwanted software attempts to install itself or to run on your computer. If you enable this policy setting Windows Defender Antivirus will not prompt users to take actions on malware detections. If you disable or do not configure this policy setting Windows Defender Antivirus will prompt users to take actions on malware detections.

STIG	Date
MS Windows Defender Antivirus Security Technical Implementation Guide	2019-06-24

Details

Check Text ( C-75019r3_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn off real-time protection" is set to "Disabled" or "Not Configured". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection Criteria: If the value "DisableRealtimeMonitoring" is REG_DWORD = 0, this is not a finding. If the value does not exist, this is not a finding. If the value is 1, this is a finding.

Check Text ( C-75019r3_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn off real-time protection" is set to "Disabled" or "Not Configured".

Procedure: Use the Windows Registry Editor to navigate to the following key:
HKLM\Software\Policies\Microsoft\Windows Defender\Real-Time Protection

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

If the value does not exist, this is not a finding.

If the value is 1, this is a finding.

Fix Text (F-81837r2_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Real-time Protection -> "Turn off real-time protection" to "Disabled" or "Not Configured".