The SIP security mode in Lync must be enabled.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-223344 | SRG-APP-000219 | O365-LY-000001 | SV-223344r1043178_rule | 2026-02-12 | 3 |
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.
ℹ️ Check
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
Set the policy value for Computer Configuration >> Administrative Templates >> Skype for Business 2016 >> Microsoft Lync Feature Policies "Configure SIP security mode" to "Enabled".