Asterisk 13.13 < 13.13-cert3 / 13.x < 13.14.1 / 14.x < 14.3.1 CDR user Field RCE (AST-2017-001)
High Nessus Plugin ID 99363
SynopsisA telephony application running on the remote host is affected by a remote code execution vulnerability.
DescriptionAccording to its SIP banner, the version of Asterisk running on the remote host is 13.13 prior to 13.13-cert3, 13.x prior to 13.14.1, or 14.x prior to 14.3.1. Is it, therefore, affected by a buffer overflow condition due to a failure to check the size when setting the user field on a CDR. An authenticated, remote attacker can exploit this, via a large string, to write past the end of the user field storage buffer, resulting in a denial of service condition or the execution of arbitrary code.
Note that this vulnerability affects any system using CDRs that also makes use of the following :
- The 'X-ClientCode' header within a SIP INFO message when using chan_sip and the 'useclientcode' option is enabled (which is disabled by default).
- The CDR dialplan() function executed from AMI when setting the user field.
- The AMI Monitor action when using a long file name or path.
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 13.13-cert3 / 13.14.1 / 14.3.1 or later.