Asterisk Project Security Advisory – AST-2014-016

Product Asterisk
Summary Remote Crash Vulnerability in PJSIP channel driver
Nature of Advisory Denial of Service
Susceptibility Remote Unauthenticated Sessions
Severity Critical
Exploits Known No
Reported On 17 November 2014
Reported By Joshua Colp
Posted On 20 November 2014
Last Updated On November 20, 2014
Advisory Contact Joshua Colp
CVE Name Pending

Description When handling an INVITE with Replaces message the
res_pjsip_refer module incorrectly assumes that it will be
operating on a channel that has just been created. If the
INVITE with Replaces message is sent in-dialog after a
session has been established this assumption will be
incorrect. The res_pjsip_refer module will then hang up a
channel that is actually owned by another thread. When this
other thread attempts to use the just hung up channel it
will end up using freed channel which will likely cause a
crash.

Resolution If REFER support is not required the res_pjsip_refer module
can be unloaded to limit exposure otherwise the
res_pjsip_refer module has been patched so it will not allow
an in-dialog INVITE with Replaces message to be processed.

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-2014-016-12.diff Asterisk
12
http://downloads.asterisk.org/pub/security/AST-2014-016-13.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This document may be superseded by later versions; if so, the latest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-2014-016.pdf and
http://downloads.digium.com/pub/security/AST-2014-016.html

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

Asterisk Project Security Advisory – AST-2014-016
Copyright (c) 2014 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.