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

From Microsoft Skype for Business 2016 STIG

Part of DTOO421 - Session Initiation Protocol (SIP) security mode

Associated with: CCI-001184

SV-85527r1_rule Session Initiation Protocol (SIP) security mode must be configured.

Vulnerability discussion

Skype for Business 2016 provides a single, unified client for real-time communications, including voice and video calls, Lync Meetings, presence, instant messaging, and persistent chat, using the Session Initiation Protocol (SIP). SIP is widely used for controlling multimedia communication sessions, such as voice and video calls over Internet Protocol (IP) networks. By using TLS it would render a sniff/man in the middle attack very difficult to impossible to achieve within the time period in which a given conversation could be attacked. TLS authenticates all parties and encrypts all traffic. This does not prevent listening over the wire, but the attacker cannot read the traffic unless the encryption is broken.

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Fix text

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

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