Title

Trusted add-ins behavior for email must be configured. (Cat II impact)

Discussion

The Outlook object model includes entry points to access Outlook data, save data to specified locations, and send email messages, all of which can be used by malicious application developers. To help protect these entry points, the Object Model Guard warns users and prompts them for confirmation when untrusted code, including add-ins, attempts to use the object model to obtain email address information, store data outside of Outlook, execute certain actions, and send email messages. To reduce excessive security warnings when add-ins are used, administrators can specify a list of trusted add-ins that can access the Outlook object model silently, without raising prompts. This trusted add-in list should be treated with care, because a malicious add-in could access and forward sensitive information if added to the list.

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Security Form Settings -> Programmatic Security -> Trusted Add-ins "Configure trusted add-ins" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\Outlook\security\trustedaddins In some reported configurations, the registry key remains after disabling the setting but the value is empty. If the registry key exists, with entries, this is a finding. If the registry key exists, but with no entries, this is not a finding.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Security Form Settings -> Programmatic Security -> Trusted Add-ins "Configure trusted add-ins" to "Disabled".

Additional Identifiers

Rule ID: SV-54002r2_rule

Vulnerability ID: V-17575

Group Title: DTOO256 - Trusted Add-Ins Security

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.