Asterisk chan_pjsip Incompatible Codecs DoS (AST-2015-001)
Medium Nessus Plugin ID 81205
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 has a flaw in which it fails to reclaim allocated RTP ports whenever a connection is made to an authenticated endpoint whose SPD offers only codecs that are not allowed by Asterisk. An attacker could exploit this vulnerability to cause an exhaustion of available ports, leading to a denial of service. Note that this only affects Asterisk using the PJSIP channel driver.
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 12.8.1 / 13.1.1 or apply the appropriate patch listed in the Asterisk advisory.