Microsoft Defender AV must use advanced protection against ransomware.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-278650 | WNDF-AV-000046 | SV-278650r1190732_rule | CCI-001170 | medium |
| Description | ||||
| This policy setting provides an extra layer of protection against ransomware. It uses both client and cloud heuristics to determine whether a file resembles ransomware. This rule does not block files that have one or more of the following characteristics: - The file is found to be unharmful in the Microsoft cloud. - The file is a valid signed file. - The file is prevalent enough to not be considered as ransomware. - The rule tends to err on the side of caution to prevent ransomware. | ||||
| STIG | Date | |||
| Microsoft Defender Antivirus Security Technical Implementation Guide | 2026-02-17 | |||
Details
Check Text (C-278650r1190732_chk)
Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Microsoft Defender Exploit Guard >> Attack Surface Reduction >> Configure Attack Surface Reduction rules is set to "Enabled".
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 "c1db55ab-c21a-4637-bb3f-a12568109d35" is REG_SZ = 1, this is not a finding.
If the value is other than 1, this is a finding.
Fix Text (F-83089r1190731_fix)
Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Microsoft Defender Exploit Guard >> Attack Surface Reduction >> Configure Attack Surface Reduction rules to "Enabled".
Under the policy option "Set the state for each ASR rule:", then click "Show".
Enter GUID "c1db55ab-c21a-4637-bb3f-a12568109d35" in the "Value Name" column.
Enter "1" in the "Value" column.