A telephony application running on the remote host is affected by a denial of service vulnerability.
According to the version in its SIP banner, the version of Asterisk running on the remote host is potentially affected by a denial of service vulnerability. A flaw exists in the handling of TCP and TLS connections when the connection is initiated but not completed. A remote attacker could repeatedly send such requests that may result in a denial of service. 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 184.108.40.206 / 11.10.1 / 12.3.1 / Certified Asterisk 1.8.15-cert6 / 11.6-cert3, or apply the appropriate patch listed in the Asterisk advisory.