Microsoft Defender AV must enable asynchronous inspection.

Documentable No

Rule ID SV-278678r1144079_rule

CCI References

CCI-001170

Discussion

Network protection includes performance optimization that allows block mode to asynchronously inspect long-lived connections, which might provide a performance improvement. This optimization can also help with app compatibility problems.

Check Procedure

Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Network Inspection System >> Turn on asynchronous inspection 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\NIS

Criteria: If the value "AllowSwitchToAsyncInspection" is REG_DWORD = 1, this is not a finding.

If the value is 0, this is a finding.

Fix Action

Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> MpEngine >> Turn on asynchronous inspection to "Enabled".

Click "OK".

Click "Apply".