A telephony application running on the remote host is affected by a privilege escalation vulnerability.
According to the version in its SIP banner, the version of Asterisk running on the remote host is potentially affected by a privilege escalation vulnerability. A flaw exists in the Asterisk Manager Interface (AMI) which allows manager users to execute arbitrary shell commands subject to the privileges of the Asterisk process. This flaw exists due to the lack of authorization of the MixMonitor manager action. Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Upgrade to Asterisk 11.10.1 / 12.3.1 / Certified Asterisk 11.6-cert3, or apply the appropriate patch listed in the Asterisk advisory.