Windows Defender AV must be configured to block the Potentially Unwanted Application (PUA) feature.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75147	WNDF-AV-000001	SV-89827r3_rule		High

Description
After enabling this feature, PUA protection blocking takes effect on endpoint clients after the next signature update or computer restart. Signature updates take place daily under typical circumstances. PUA will be blocked and automatically quarantined.

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

Details

Check Text ( C-74939r6_chk )
Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Windows Defender Antivirus >> "Configure detection for potentially unwanted applications" is set to "Enabled" and "Block". Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender If the value "PUAProtection" does not exist, this is a finding. If the value "PUAProtection" is REG_DWORD = 1, this is not a finding.

Check Text ( C-74939r6_chk )

Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Windows Defender Antivirus >> "Configure detection for potentially unwanted applications" is set to "Enabled" and "Block".

Use the Windows Registry Editor to navigate to the following key:

HKLM\Software\Policies\Microsoft\Windows Defender

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

If the value "PUAProtection" is REG_DWORD = 1, this is not a finding.

Fix Text (F-81759r4_fix)
Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Windows Defender Antivirus >> "Configure Detection for Potentially Unwanted Applications" to "Enabled" and "Block".