In the event a secure Session Initiation Protocol (SIP) connection fails, the connection must be restricted from resorting to the unencrypted HTTP.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-70905 | DTOO422 | SV-85529r1_rule | CCI-001184 | medium |
| Description | ||||
| Prevents from HTTP being used for SIP connection in case TLS or TCP fail. | ||||
| STIG | Date | |||
| Microsoft Skype for Business 2016 Security Technical Implementation Guide | 2016-11-02 | |||
Details
Check Text (C-85529r1_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".
Procedure: Use the Windows Registry Editor to navigate to the following key:
HKLM\Software\Policies\Microsoft\office\16.0\lync
Criteria: If the value disablehttpconnect is REG_DWORD = 1, this is not a finding.
Fix Text (F-77237r1_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".