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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17734	DTOO280	SV-54053r1_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 2013 STIG	2017-03-17

Details

Check Text ( C-47993r1_chk )
Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Account Settings -> Exchange "Authentication with Exchange Server" is set to "Enabled (Kerberos/NTLM Password Authentication)". 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 AuthenticationService is REG_DWORD = 9, this is not a finding.

Check Text ( C-47993r1_chk )

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Account Settings -> Exchange "Authentication with Exchange Server" is set to "Enabled (Kerberos/NTLM Password Authentication)".

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 AuthenticationService is REG_DWORD = 9, this is not a finding.

Fix Text (F-46933r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Account Settings -> Exchange "Authentication with Exchange Server" to "Enabled (Kerberos/NTLM Password Authentication)".