Windows Defender AV must be configured block Office applications from creating child processes.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-77967	WNDF-AV-000033	SV-92663r1_rule		Medium

Description
Office apps, such as Word or Excel, will not be allowed to create child processes. This is a typical malware behavior, especially for macro-based attacks that attempt to use Office apps to launch or download malicious executables.

STIG	Date
MS Windows Defender Antivirus Security Technical Implementation Guide	2019-06-24

Details

Check Text ( C-77577r1_chk )
This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions. Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows: Value name: D4F940AB-401B-4EFC-AADC-AD5F3C50688A Value: 1 Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules Criteria: If the value “D4F940AB-401B-4EFC-AADC-AD5F3C50688A” is REG_SZ = 1, this is not a finding.

Check Text ( C-77577r1_chk )

This setting is applicable starting with v1709 of Windows 10, it is NA for prior versions.

Verify the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" is set to "Enabled”. Click ‘Show...’. Verify the rule ID in the Value name column and the desired state in the Value column is set as follows:
Value name: D4F940AB-401B-4EFC-AADC-AD5F3C50688A
Value: 1

Procedure: Use the Windows Registry Editor to navigate to the following key:
HKLM\Software\Policies\Microsoft\Windows Defender\Windows Defender Exploit Guard\ASR\Rules

Criteria: If the value “D4F940AB-401B-4EFC-AADC-AD5F3C50688A” is REG_SZ = 1, this is not a finding.

Fix Text (F-84679r1_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Windows Components -> Windows Defender Antivirus -> Windows Defender Exploit Guard -> Attack Surface Reduction -> "Configure Attack Surface Reduction rules" to "Enabled”. Click ‘Show...’. Set the Value name to “D4F940AB-401B-4EFC-AADC-AD5F3C50688A” and the Value to “1”.