Microsoft Defender AV must set cloud protection level to High.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-278863	SRG-APP-000210	WNDF-AV-000073	SV-278863r1144086_rule	2025-11-25	2

Description
Cloud protection in Microsoft Defender Antivirus delivers accurate, real-time, and intelligent protection. Cloud protection should be enabled by default.

ℹ️ Check
Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> MpEngine >> Select cloud protection level is set to "Enabled". Verify the policy value for "Select cloud blocking level" is set to "High blocking level"; otherwise, this is a finding. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\MpEngine Criteria: If the value "MpCloudBlockLevel" is REG_DWORD = 2, this is not a finding. If the value is other than 2, this is a finding.

ℹ️ Check

Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> MpEngine >> Select cloud protection level is set to "Enabled". Verify the policy value for "Select cloud blocking level" is set to "High blocking level"; otherwise, this is a finding. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\MpEngine Criteria: If the value "MpCloudBlockLevel" is REG_DWORD = 2, this is not a finding. If the value is other than 2, this is a finding.

✔️ Fix
Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> MpEngine >> Select cloud protection level to "Enabled". Set policy value "Select cloud blocking level" to "High blocking level". Click "OK". Click "Apply".