Microsoft Defender AV must be configured to turn on e-mail scanning.

Documentable No

Rule ID SV-213451r961092_rule

CCI References

CCI-001170

Discussion

This policy setting allows the configuration of e-mail scanning. When e-mail scanning is enabled, the engine will parse the mailbox and mail files according to their specific format in order to analyze the mail bodies and attachments. Several e-mail formats are currently supported, for example: pst (Outlook), dbx mbx mime (Outlook Express), binhex (Mac). If this setting is enabled, e-mail scanning will be enabled. If this setting is disabled or not configured, e-mail scanning will be disabled.

Check Procedure

Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Scan >> "Turn on e-mail scanning" is set to "Enabled".
  
Procedure: Use the Windows Registry Editor to navigate to the following key: 
HKLM\Software\Policies\Microsoft\Windows Defender\Scan

Criteria: If the value "DisableEmailScanning" is REG_DWORD = 0, this is not a finding.

Fix Action

Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Scan >> "Turn on e-mail scanning" to "Enabled".