Active X One-Off forms must only be enabled to load with Outlook Controls. (Cat II impact)
By default, third-party ActiveX controls are not allowed to run in one-off forms in Outlook. You can change this behavior so that Safe Controls (Microsoft Forms 2.0 controls and the Outlook Recipient and Body controls) are allowed in one-off forms, or so that all ActiveX controls are allowed to run.
Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Outlook 2016 >> Security >> Allow Active X One Off Forms is set to "Enabled" "Load only Outlook Controls". Use the Windows Registry to navigate to the following key: HKCU\software\policies\microsoft\office\16.0\outlook\security If the value for allowactivexoneoffforms is REG_DWORD = 0, this is not a finding.
Set the policy value for User Configuration >> Administrative Templates >> Microsoft Outlook 2016 >> Security >> Allow Active X One Off Forms to "Enabled" "Load only Outlook Controls".
Rule ID: SV-223352r508019_rule
Vulnerability ID: V-223352
Group Title: SRG-APP-000210
The information system prevents the automatic execution of mobile code in organization-defined software applications.
Prevent Automatic Execution