Windows Defender AV must be configured for automatic remediation action to be taken for threat alert level High.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-79965	WNDF-AV-000040	SV-94669r1_rule		Medium

Description
This policy setting allows you to customize which automatic remediation action will be taken for each threat alert level. Threat alert levels should be added under the Options for this setting. Each entry must be listed as a name value pair. The name defines a threat alert level. The value contains the action ID for the remediation action that should be taken. Valid threat alert levels are: 1 = Low 2 = Medium 4 = High 5 = Severe Valid remediation action values are: 2 = Quarantine 3 = Remove 6 = Ignore

Description

This policy setting allows you to customize which automatic remediation action will be taken for each threat alert level. Threat alert levels should be added under the Options for this setting. Each entry must be listed as a name value pair. The name defines a threat alert level. The value contains the action ID for the remediation action that should be taken. Valid threat alert levels are: 1 = Low 2 = Medium 4 = High 5 = Severe Valid remediation action values are: 2 = Quarantine 3 = Remove 6 = Ignore

STIG	Date
MS Windows Defender Antivirus Security Technical Implementation Guide	2018-03-29

Details

Check Text ( C-79633r2_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" is set to "Enabled". Click the “Show…” box option and verify the ‘Value name’ field contains a value of “4” and the ‘Value’ field contains a “2". A value of “3” in the ‘Value’ field is more restrictive and also an acceptable value. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Threats\ThreatSeverityDefaultAction Criteria: If the value "4" is REG_SZ = 2 (or 3), this is not a finding.

Check Text ( C-79633r2_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" is set to "Enabled". Click the “Show…” box option and verify the ‘Value name’ field contains a value of “4” and the ‘Value’ field contains a “2". A value of “3” in the ‘Value’ field is more restrictive and also an acceptable value.

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

Criteria: If the value "4" is REG_SZ = 2 (or 3), this is not a finding.

Fix Text (F-86769r1_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Threats -> "Specify threat alert levels at which default action should not be taken when detected" to "Enabled". Select the “Show…” option box and enter "4” in the ‘Value name’ field and enter “2" in the ‘Value’ field.