Detections
Analytics
2.5.14.3.3.7 Ensure 'Configure Outlook object model prompt when sending mail' is set to 'Enabled: Automatically Deny'
Information
This policy setting controls what happens when an untrusted program attempts to send e-mail programmatically using the Outlook object model.When the option Automatically deny is selected, Outlook will automatically deny programmatic access requests from any program.
The recommended state for this setting is: Enabled: Automatically Deny.
Rationale:
If an untrusted application programmatically sends e-mail, that application could send mail that includes malicious code, impersonates a user, or launches a denial-of-service attack by sending a large volume of mail to a user or group of users.
Impact:
An untrusted program will not be able to send e-mail programmatically using the Outlook object model.
Important: For this setting to apply, the Outlook Security Mode setting must be enabled in User Configuration\Administrative Templates\Microsoft Outlook 2016\Security\Security with Use Outlook Security Group Policy selected, as set in this benchmark in Section 2.5.14.3.
If Group Policy security settings are used for Outlook, the Programmatic Access section of the Trust Center is not used. In this situation, the default is to prompt users based on computer security, which is the equivalent of the Only when antivirus software is out of date or not running option in the Trust Center, and the user experience is not affected.
Solution
To establish the recommended configuration via GP, set the following UI path to Enabled: Automatically Deny:User Configuration\Administrative Templates\Microsoft Outlook 2016\Security\Security Form Settings\Programmatic Security\Configure Outlook object model prompt when sending mail
Default Value:
Enabled: Prompt user based on computer security. (Outlook will only prompt users when antivirus software is out of date or not running.)
When an untrusted application attempts to send mail programmatically, Outlook relies on the setting configured in the ''Programmatic Access'' section of the Trust Center.
Additional Information:
By default, when an untrusted application attempts to send mail programmatically, Outlook relies on the setting configured in the 'Programmatic Access' section of the Trust Center. This setting determines whether Outlook will warn users about programmatic access attempts:
Only when antivirus software is out of date or not running (the default setting)
Every time
Not at all
If the 'Not at all' option is selected, Outlook will silently grant programmatic access to any program that requests it, which could allow a malicious program to gain access to sensitive information. Note: This described default functionality assumes that you have not followed the recommendation to enable the 'Outlook Security Mode' Group Policy setting to ensure that Outlook security settings are configured by Group Policy. If Group Policy security settings are used for Outlook, the 'Programmatic Access' section of the Trust Center is not used. In this situation, the default is to prompt users based on computer security, which is the equivalent of the 'Only when antivirus software is out of date or not running' option in the Trust Center, and the user experience is not affected.
See Also
Item Details
Audit Name: CIS Microsoft Office Enterprise v1.1.0 L1
Category: CONFIGURATION MANAGEMENT, SYSTEM AND COMMUNICATIONS PROTECTION
References: 800-53|CM-10, 800-53|CM-11, 800-53|SC-18
Plugin: Windows
Control ID: 202be906b25e3b9f0383cfd0f2fc2f2cc8fc7cbc4db9dfb2076d0fa365f9a794