Asterisk Project Security Advisory – AST-2014-014

Product Asterisk
Summary High call load may result in hung channels in
ConfBridge.
Nature of Advisory Denial of Service
Susceptibility Remote Unauthenticated Sessions
Severity Moderate
Exploits Known No
Reported On 19 October, 2014
Reported By Ben Klang
Posted On 20 November 2014
Last Updated On November 20, 2014
Advisory Contact Joshua Colp
CVE Name Pending

Description The ConfBridge application uses an internal bridging API to
implement conference bridges. This internal API uses a
state model for channels within the conference bridge and
transitions between states as different things occur. Under
load it is possible for some state transitions to be
delayed causing the channel to transition from being hung
up to waiting for media. As the channel has been hung up
remotely no further media will arrive and the channel will
stay within ConfBridge indefinitely.

Resolution The underlying bridging code that ConfBridge uses has been
fixed so state changes can not occur that will take a
channel out of the hung up state.

Affected Versions
Product Release
Series
Asterisk Open Source 11.x All versions
Certified Asterisk 11.6 All versions

Corrected In
Product Release
Asterisk Open Source 11.14.1
Certified Asterisk 11.6-cert8

Patches
SVN URL Revision
http://downloads.asterisk.org/pub/security/AST-2014-014-11.diff Asterisk
11
http://downloads.asterisk.org/pub/security/AST-2014-014-11.6.diff Certified
Asterisk
11.6

Links https://issues.asterisk.org/jira/browse/ASTERISK-24440

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This document may be superseded by later versions; if so, the latest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-2014-014.pdf and
http://downloads.digium.com/pub/security/AST-2014-014.html

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

Asterisk Project Security Advisory – AST-2014-014
Copyright (c) 2014 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.