Microsoft Defender AV must block untrusted and unsigned processes that run from USB.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-278649	SRG-APP-000210	WNDF-AV-000045	SV-278649r1144034_rule	2025-11-25	2

Description
This policy setting helps prevents unsigned or untrusted executable files from running from USB removable drives, including SD cards. Blocked file types include executable files (such as .exe, .dll, or .scr).

ℹ️ Check
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 "b2b3f03d-6a65-4f7b-a9c7-1c7ef74a9ba4" is REG_SZ = 1, this is not a finding. If the value is other than 1, this is a finding.

ℹ️ Check

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 "b2b3f03d-6a65-4f7b-a9c7-1c7ef74a9ba4" is REG_SZ = 1, this is not a finding. If the value is other than 1, this is a finding.

✔️ 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 "b2b3f03d-6a65-4f7b-a9c7-1c7ef74a9ba4" in the "Value Name" column. Enter "1" in the "Value" column. Click "OK". Click "Apply".

✔️ 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 "b2b3f03d-6a65-4f7b-a9c7-1c7ef74a9ba4" in the "Value Name" column. Enter "1" in the "Value" column. Click "OK". Click "Apply".