The HTTP fallback for SIP connection in Lync must be disabled.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-223345 | O365-LY-000002 | SV-223345r1043178_rule | CCI-001184 | medium |
| Description | ||||
| Prevents from HTTP being used for SIP connection in case TLS or TCP fail. | ||||
| STIG | Date | |||
| Microsoft Office 365 ProPlus Security Technical Implementation Guide | 2025-03-05 | |||
Related Frameworks
3 paths across 3 frameworks
Related Frameworks
NIST 800-531 mapping
SC-23
1.00
- DISA · 3 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
NIST 800-1711 mapping
3.13.15
1.00
- DISA · 3 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
- NIST · Rev 2 (Feb 2020, errata Jan 2021) · nist_800_171_app_d · equivalent
CCI1 mapping
CCI-001184
1.00
- DISA · 3 · disa_xccdf · related
Details
Check Text (C-223345r1043178_chk)
Verify the policy value for Computer Configuration >> Administrative Templates >> Skype for Business 2016 >> Microsoft Lync Feature Policies "Disable HTTP fallback for SIP connection" 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 disablehttpconnect is REG_DWORD = 1, this is not a finding.
Fix Text (F-25006r442255_fix)
Set the policy value for Computer Configuration >> Administrative Templates >> Skype for Business 2016 >> Microsoft Lync Feature Policies "Disable HTTP fallback for SIP connection" to "Enabled".