Microsoft Defender AV must report Dynamic Signature dropped events.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-278675 | WNDF-AV-000071 | SV-278675r1190765_rule | CCI-001170 | medium |
| Description | ||||
| Microsoft Defender Antivirus logs "Dynamic Signature dropped" events when it blocks or removes a file based on a dynamically updated signature, but the signature itself is dropped, meaning it was not fully processed or applied. This can indicate a potential issue with signature updates or the system's ability to handle them. | ||||
| STIG | Date | |||
| Microsoft Defender Antivirus Security Technical Implementation Guide | 2026-02-17 | |||
Details
Check Text (C-278675r1190765_chk)
Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Reporting >> Configure whether to report Dynamic Signature dropped events is set to "Enabled"; otherwise, this is a finding.
Procedure: Use the Windows Registry Editor to navigate to the following key:
HKLM\Software\Policies\Microsoft\Windows Defender\Reporting
Criteria: If the value "EnableDynamicSignatureDroppedEventReporting" is REG_DWORD = 1, this is not a finding.
If the value is 0, this is a finding.
Fix Text (F-83114r1190764_fix)
Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Reporting >> Configure whether to report Dynamic Signature dropped events to "Enabled".