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

From MS Windows Defender Antivirus Security Technical Implementation Guide

Associated with: CCI-001242

SV-89835r2_rule Windows Defender AV must be configured to not exclude files for scanning.

Vulnerability discussion

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.

Check content

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

Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Exclusions -> "Path Exclusions" to "Disabled" or "Not Configured".

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