Outlook must be configured to force authentication when connecting to an Exchange server.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-71255	DTOO280	SV-85879r1_rule		Medium

Description
Exchange Server supports the Kerberos authentication protocol and NTLM for authentication. The Kerberos protocol is the more secure authentication method and is supported on Windows 2000 Server and later versions. NTLM authentication is supported in pre-Windows 2000 environments. When authentication is enabled, Outlook will attempt to authenticate using the Kerberos authentication protocol, if it cannot (because no Windows 2000 or later domain controllers are available), it will authenticate using NTLM, ensuring a more secure authentication to the Exchange server.

Description

Exchange Server supports the Kerberos authentication protocol and NTLM for authentication. The Kerberos protocol is the more secure authentication method and is supported on Windows 2000 Server and later versions. NTLM authentication is supported in pre-Windows 2000 environments. When authentication is enabled, Outlook will attempt to authenticate using the Kerberos authentication protocol, if it cannot (because no Windows 2000 or later domain controllers are available), it will authenticate using NTLM, ensuring a more secure authentication to the Exchange server.

STIG	Date
Microsoft Outlook 2016 STIG	2016-07-28

Details

Check Text ( None )
None

Fix Text (F-46933r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2016 -> Account Settings -> Exchange "Authentication with Exchange Server" to "Enabled (Kerberos Password Authentication)".