Asterisk PJProject TCP Connection DoS (AST-2016-005)
Medium Nessus Plugin ID 90997
SynopsisA telephony application running on the remote host is affected by a denial of service vulnerability.
DescriptionAccording to its SIP banner, the version of Asterisk running on the remote host is either 13.x prior to 13.8.1 or 13.1-cert prior to 13.1-cert5. It is, therefore, affected by a flaw in PJProject due to a failure to close TCP connections after receiving new ones. An unauthenticated, remote attacker can exploit this, by opening multiple connections without sending data, to exhaust the number of allowed TCP connections, resulting in a denial of service condition.
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
SolutionUpgrade to Asterisk version 13.8.1 / 13.1-cert5, or apply the appropriate patch according to the Asterisk advisory.