Message formats must be set to use SMime.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17755	DTOO260 - Outlook	SV-33563r1_rule		Medium

Description
E-mail typically travels over open networks and is passed from server to server. Messages are therefore vulnerable to interception, and attackers might read or alter their contents. It is therefore important to have a mechanism for signing messages and providing end-to-end encryption. Outlook supports three formats for encrypting and signing messages: S/MIME, Exchange, and Fortezza. By default, Outlook only uses S/MIME to encrypt and sign messages. If your organization has policies that mandate the use of specific encryption formats, allowing users to choose freely between these formats could cause them to violate such policies.

Description

E-mail typically travels over open networks and is passed from server to server. Messages are therefore vulnerable to interception, and attackers might read or alter their contents. It is therefore important to have a mechanism for signing messages and providing end-to-end encryption. Outlook supports three formats for encrypting and signing messages: S/MIME, Exchange, and Fortezza. By default, Outlook only uses S/MIME to encrypt and sign messages. If your organization has policies that mandate the use of specific encryption formats, allowing users to choose freely between these formats could cause them to violate such policies.

STIG	Date
Microsoft Outlook 2010 STIG	2018-04-04

Details

Check Text ( C-34024r1_chk )
The policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Cryptography “Message Formats” must be set to “Enabled (S\MIME)”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\14.0\outlook\security Criteria: If the value MsgFormats is REG_DWORD = 1, this is not a finding.

Fix Text (F-29709r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Cryptography “Message Formats” to “Enabled (S\MIME)”.