Custom Outlook Object Model (OOM) action execution prompts must be configured.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17802	DTOO247	SV-53994r1_rule		Medium

Description
Custom actions add functionality to Outlook that can be triggered as part of a rule. Among other possible features, custom actions can be created that reply to messages in ways that circumvent the Outlook model's programmatic send protections. By default, when Outlook or another program initiates a custom action using the Outlook object model, users are prompted to allow or reject the action. If this configuration is changed, malicious code can use the Outlook object model to compromise sensitive information or otherwise cause data and computing resources to be at risk.

Description

Custom actions add functionality to Outlook that can be triggered as part of a rule. Among other possible features, custom actions can be created that reply to messages in ways that circumvent the Outlook model's programmatic send protections. By default, when Outlook or another program initiates a custom action using the Outlook object model, users are prompted to allow or reject the action. If this configuration is changed, malicious code can use the Outlook object model to compromise sensitive information or otherwise cause data and computing resources to be at risk.

STIG	Date
Microsoft Outlook 2013 STIG	2017-03-17

Details

Check Text ( C-47965r1_chk )
Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Security Form Settings -> Custom Form Security "Set Outlook object model Custom Actions execution prompt" is "Enabled (Automatically Deny)". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\outlook\security Criteria: If the value PromptOOMCustomAction is REG_DWORD = 0, this is not a finding.

Check Text ( C-47965r1_chk )

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Security Form Settings -> Custom Form Security "Set Outlook object model Custom Actions execution prompt" is "Enabled (Automatically Deny)".

Procedure: Use the Windows Registry Editor to navigate to the following key:

HKCU\Software\Policies\Microsoft\Office\15.0\outlook\security

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

Fix Text (F-46883r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Security Form Settings -> Custom Form Security "Set Outlook object model Custom Actions execution prompt" to "Enabled (Automatically Deny)".