Windows Defender AV must be configured to not exclude files for scanning.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75155	WNDF-AV-000005	SV-89835r2_rule		Medium

Description
This policy setting allows you to disable scheduled and real-time scanning for files under the paths specified or for the fully qualified resources specified. Paths should be added under the Options for this setting. Each entry must be listed as a name value pair where the name should be a string representation of a path or a fully qualified resource name. As an example a path might be defined as: "c:\Windows" to exclude all files in this directory. A fully qualified resource name might be defined as: "C:\Windows\App.exe". The value is not used and it is recommended that this be set to 0.

Description

This policy setting allows you to disable scheduled and real-time scanning for files under the paths specified or for the fully qualified resources specified. Paths should be added under the Options for this setting. Each entry must be listed as a name value pair where the name should be a string representation of a path or a fully qualified resource name. As an example a path might be defined as: "c:\Windows" to exclude all files in this directory. A fully qualified resource name might be defined as: "C:\Windows\App.exe". The value is not used and it is recommended that this be set to 0.

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

Details

Check Text ( C-74947r3_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Path Exclusions" 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\Exclusions Criteria: If the value "Exclusions_Paths" does not exist, this is not a finding.

Check Text ( C-74947r3_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Path Exclusions" 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\Exclusions

Criteria: If the value "Exclusions_Paths" does not exist, this is not a finding.

Fix Text (F-81767r2_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Path Exclusions" to "Disabled" or "Not Configured".