Microsoft Defender AV must block untrusted and unsigned processes that run from USB.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-278649 | WNDF-AV-000045 | SV-278649r1190730_rule | CCI-001170 | medium |
| 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). | ||||
| STIG | Date | |||
| Microsoft Defender Antivirus Security Technical Implementation Guide | 2026-02-17 | |||
Details
Check Text (C-278649r1190730_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 "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 Text (F-83088r1190729_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.