Asterisk Project Security Advisory – AST-2014-015

Product Asterisk
Summary Remote Crash Vulnerability in PJSIP channel driver
Nature of Advisory Denial of Service
Susceptibility Remote Unauthenticated Sessions
Severity Moderate
Exploits Known No
Reported On 30 October 2014
Reported By Yaron Nahum
Posted On 20 November 2014
Last Updated On November 20, 2014
Advisory Contact Joshua Colp
CVE Name Pending

Description The chan_pjsip channel driver uses a queue approach for
actions relating to SIP sessions. There exists a race
condition where actions may be queued to answer a session
or send ringing AFTER a SIP session has been terminated
using a CANCEL request. The code will incorrectly assume
that the SIP session is still active and attempt to send
the SIP response. The PJSIP library does not expect the SIP
session to be in the disconnected state when sending the
response and asserts.

Resolution Asterisk has been patched so any queued actions that occur
after a SIP session has been disconnected will not execute.

Affected Versions
Product Release
Series
Asterisk Open Source 12.x All versions
Asterisk Open Source 13.x All versions

Corrected In
Product Release
Asterisk Open Source 12.7.1, 13.0.1

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2014-015-12.diff Asterisk
12
http://downloads.asterisk.org/pub/security/AST-2014-015-13.diff Asterisk
13

Links https://issues.asterisk.org/jira/browse/ASTERISK-24471

Asterisk Project Security Advisories are posted at
http://www.asterisk.org/security

This document may be superseded by later versions; if so, the latest
version will be posted at
http://downloads.digium.com/pub/security/AST-2014-015.pdf and
http://downloads.digium.com/pub/security/AST-2014-015.html

Revision History
Date Editor Revisions Made
November 20 2014 Joshua Colp Initial Revision

Asterisk Project Security Advisory – AST-2014-015
Copyright (c) 2014 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.