Session Initiation Protocol (SIP) security mode must be configured.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-70903	DTOO421	SV-85527r1_rule		Medium

Description
When Lync connects to the server, it supports various authentication mechanisms. This policy allows the user to specify whether Digest and Basic authentication are supported. Disabled (default): NTLM/Kerberos/TLS-DSK/Digest/Basic Enabled: Authentication mechanisms: NTLM/Kerberos/TLS-DSK Gal Download: Requires HTTPS if user is not logged in as an internal user.

STIG	Date
Microsoft Skype for Business 2016 Security Technical Implementation Guide	2016-11-02

Details

Check Text ( C-71347r2_chk )
Verify the policy value for Computer Configuration -> Administrative Templates -> Skype for Business 2016 -> Microsoft Lync Feature Policies "Configure SIP security mode" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\office\16.0\lync Criteria: If the value enablesiphighsecuritymode is REG_DWORD = 1, this is not a finding.

Check Text ( C-71347r2_chk )

Verify the policy value for Computer Configuration -> Administrative Templates -> Skype for Business 2016 -> Microsoft Lync Feature Policies "Configure SIP security mode" is set to "Enabled".

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

HKLM\Software\Policies\Microsoft\office\16.0\lync

Criteria: If the value enablesiphighsecuritymode is REG_DWORD = 1, this is not a finding.

Fix Text (F-77235r1_fix)
Set the policy value for Computer Configuration -> Administrative Templates -> Skype for Business 2016 -> Microsoft Lync Feature Policies "Configure SIP security mode" to "Enabled".