The SIP security mode in Lync must be enabled.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-223344 | O365-LY-000001 | SV-223344r1043178_rule | CCI-001184 | 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 Office 365 ProPlus Security Technical Implementation Guide | 2025-03-05 | |||
Details
Check Text (C-223344r1043178_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".
Use the Windows Registry Editor to navigate to the following key:
HKLM\Software\Policies\Microsoft\office\16.0\lync
If the value enablesiphighsecuritymode is REG_DWORD = 1, this is not a finding.
Fix Text (F-25005r442252_fix)
Set the policy value for Computer Configuration >> Administrative Templates >> Skype for Business 2016 >> Microsoft Lync Feature Policies "Configure SIP security mode" to "Enabled".