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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75147	WNDF-AV-000001	SV-89827r2_rule		High

Description
After enabling this feature, Potentially Unwanted Application (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	2019-06-24

Details

Check Text ( C-74939r4_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> MS Security Guide -> "Turn on Windows Defender protection against Potentially Unwanted Applications" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\MpEngine Criteria: If the value "MpEnablePus" is REG_DWORD = 1, this is not a finding.

Check Text ( C-74939r4_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> MS Security Guide -> "Turn on Windows Defender protection against Potentially Unwanted Applications" is set to "Enabled".

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

Criteria: If the value "MpEnablePus" is REG_DWORD = 1, this is not a finding.

Fix Text (F-81759r3_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> MS Security Guide -> "Turn on Windows Defender protection against Potentially Unwanted Applications" to “Enabled”. This policy setting requires the installation of the SecGuide custom templates included with the Windows 10 STIG package. "SecGuide.admx" and "SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.

Fix Text (F-81759r3_fix)

Set the policy value for Computer Configuration -> Administrative Templates -> MS Security Guide -> "Turn on Windows Defender protection against Potentially Unwanted Applications" to “Enabled”.

This policy setting requires the installation of the SecGuide custom templates included with the Windows 10 STIG package. "SecGuide.admx" and "SecGuide.adml" must be copied to the \Windows\PolicyDefinitions and \Windows\PolicyDefinitions\en-US directories respectively.