Asterisk Project Security Advisory - 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.
099b772e3a144709929f99b4de56abb1 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@digium.com> |
|--------------------+---------------------------------------------------|
| 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@digium.com | 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.
© 2012 Packet Storm. All rights reserved.
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