Asterisk SIP Channel Driver ACK with SDP Denial of Service (AST-2013-004)
Medium Nessus Network Monitor Plugin ID 8006
The remote VoIP server is affected by 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. The application does not properly handle 'ACK' messages with SDP after a channel has been closed.
Upgrade to Asterisk 184.108.40.206 / 11.5.1 / Certified Asterisk 1.8.15-cert3 / 11.2-cert2, or apply the appropriate patch listed in the Asterisk advisory.