[VulnWatch] ASA-2007-015: Remote Crash Vulnerability in IAX2 channel driver



Asterisk Project Security Advisory - ASA-2007-015

+------------------------------------------------------------------------+
| Product | Asterisk |
|--------------------+---------------------------------------------------|
| Summary | Remote Crash Vulnerability in IAX2 channel driver |
|--------------------+---------------------------------------------------|
| Nature of Advisory | Denial of Service |
|--------------------+---------------------------------------------------|
| Susceptibility | Remote Unauthenticated Sessions |
|--------------------+---------------------------------------------------|
| Severity | Critical |
|--------------------+---------------------------------------------------|
| Exploits Known | No |
|--------------------+---------------------------------------------------|
| Reported On | July 13, 2007 |
|--------------------+---------------------------------------------------|
| Reported By | Chris Clark and Zane Lackey, iSEC Partners |
|--------------------+---------------------------------------------------|
| Posted On | July 17, 2007 |
|--------------------+---------------------------------------------------|
| Last Updated On | July 17, 2007 |
|--------------------+---------------------------------------------------|
| Advisory Contact | Russell Bryant <russell@xxxxxxxxxx> |
|--------------------+---------------------------------------------------|
| CVE Name | CVE-2007-3763 |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| Description | The Asterisk IAX2 channel driver, chan_iax2, has a |
| | remotely exploitable crash vulnerability. A NULL pointer |
| | exception can occur when Asterisk receives a LAGRQ or |
| | LAGRP frame that is part of a valid session and includes |
| | information elements. The session used to exploit this |
| | issue does not have to be authenticated. It can simply |
| | be a NEW packet sent with an invalid username. |
| | |
| | The code that parses the incoming frame correctly parses |
| | the information elements of IAX frames. It then sets a |
| | pointer to NULL to indicate that there is not a raw data |
| | payload associated with this frame. However, it does not |
| | set the variable that indicates the number of bytes in |
| | the raw payload back to zero. Since the raw data length |
| | is non-zero, the code handling LAGRQ and LAGRP frames |
| | tries to copy data from a NULL pointer, causing a crash. |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| Resolution | All users that have chan_iax2 enabled should upgrade to |
| | the appropriate version listed in the corrected in |
| | section of this advisory. |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| Affected Versions |
|------------------------------------------------------------------------|
| Product | Release | |
| | Series | |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.0.x | All versions |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.2.x | All versions prior to |
| | | 1.2.22 |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.4.x | All versions prior to |
| | | 1.4.8 |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | A.x.x | All versions |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | B.x.x | All versions prior to |
| | | B.2.2.1 |
|----------------------------------+-------------+-----------------------|
| AsteriskNOW | pre-release | All versions prior to |
| | | beta7 |
|----------------------------------+-------------+-----------------------|
| Asterisk Appliance Developer Kit | 0.x.x | All versions prior to |
| | | 0.5.0 |
|----------------------------------+-------------+-----------------------|
| s800i (Asterisk Appliance) | 1.0.x | All versions prior to |
| | | 1.0.2 |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| Corrected In |
|------------------------------------------------------------------------|
| Product | Release |
|-------------------+----------------------------------------------------|
| Asterisk Open | 1.2.22 and 1.4.8, available from |
| Source | ftp://ftp.digium.com/pub/telephony/asterisk |
|-------------------+----------------------------------------------------|
| Asterisk Business | B.2.2.1, available from the Asterisk Business |
| Edition | Edition user portal on http://www.digium.com or |
| | |
| | via Digium Technical Support |
|-------------------+----------------------------------------------------|
| AsteriskNOW | Beta7, available from http://www.asterisknow.org/. |
| | Beta5 and Beta6 users can update using the system |
| | update feature in the appliance control panel. |
|-------------------+----------------------------------------------------|
| Asterisk | 0.5.0, available from |
| Appliance | |
| Developer Kit | ftp://ftp.digium.com/pub/telephony/aadk/ |
|-------------------+----------------------------------------------------|
| s800i (Asterisk | 1.0.2 |
| Appliance) | |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| Links | |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| 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://ftp.digium.com/pub/asa/ASA-2007-015.pdf. |
+------------------------------------------------------------------------+

+------------------------------------------------------------------------+
| Revision History |
|------------------------------------------------------------------------|
| Date | Editor | Revisions Made |
|-------------------+-------------------------+--------------------------|
| July 17, 2007 | russell@xxxxxxxxxx | Initial Release |
+------------------------------------------------------------------------+

Asterisk Project Security Advisory - ASA-2007-015
Copyright (c) 2007 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.



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