Asterisk 13.10.x < 13.11.1 ACK Handling Unrecognized Username NULL Pointer Dereference DoS (AST-2016-006)
Medium Nessus Plugin ID 93533
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 13.10.x prior to 13.11.1. It is, therefore, affected by a NULL pointer dereference flaw due to improper handling of ACK packets from an unknown username. An unauthenticated, remote attacker can exploit this to crash the program, resulting in a denial of service. This vulnerability only affects installations using the PJSIP stack; installations using chan_sip are unaffected.
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 13.11.1.