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| From: | ASTERISK | | Date: | 22.08.2007 | | Subject: | AST-2007-020: Resource Exhaustion Vulnerability in Asterisk SIP channel driver |
Asterisk Project Security Advisory - AST-2007-020
+------------------------------------------------------------------------+
| Product | Asterisk |
|--------------------+---------------------------------------------------|
| Summary | Resource Exhaustion vulnerability in SIP channel |
| | driver |
|--------------------+---------------------------------------------------|
| Nature of Advisory | Denial of Service |
|--------------------+---------------------------------------------------|
| Susceptibility | Remote Unauthenticated Sessions |
|--------------------+---------------------------------------------------|
| Severity | Moderate |
|--------------------+---------------------------------------------------|
| Exploits Known | No |
|--------------------+---------------------------------------------------|
| Reported On | August 9, 2007 |
|--------------------+---------------------------------------------------|
| Reported By | Jon Moldenauer (bugs.digium.com user |
| | jmoldenhauer) |
|--------------------+---------------------------------------------------|
| Posted On | August 21, 2007 |
|--------------------+---------------------------------------------------|
| Last Updated On | August 21, 2007 |
|--------------------+---------------------------------------------------|
| Advisory Contact | Russell Bryant <russell@digium.com> |
|--------------------+---------------------------------------------------|
| CVE Name | CVE-2007-4455 |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Description | The handling of SIP dialog history was broken during the |
| | development of Asterisk 1.4. Regardless of whether |
| | recording SIP dialog history is turned on or off, the |
| | history is still recorded in memory. Furthermore, there |
| | is no upper limit on how many history items will be |
| | stored for a given SIP dialog. |
| | |
| | It is possible for an attacker to use up all of the |
| | system's memory by creating a SIP dialog that records |
| | many entires in the history and never ends. It is also |
| | worth noting for the sake of doing the math to calculate |
| | what it would take to exploit this that each SIP history |
| | entry will take up a maximum of 88 bytes. |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Resolution | The fix that has been added to chan_sip is to restore the |
| | functionality where SIP dialog history is not recorded in |
| | memory if it is not enabled. Furthermore, a maximum of 50 |
| | entires in the history will be stored for each dialog |
| | when recording history is turned on. |
| | |
| | The only way to avoid this problem in affected versions |
| | of Asterisk is to disable chan_sip. If chan_sip is being |
| | used, the system must be upgraded to a version that has |
| | this issue resolved. |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Affected Versions |
|------------------------------------------------------------------------|
| Product | Release | |
| | Series | |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.0.x | Not affected |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.2.x | Not affected |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.4.x | All versions prior to |
| | | 1.4.11 |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | A.x.x | Not affected |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | B.x.x | Not affected |
|----------------------------------+-------------+-----------------------|
| AsteriskNOW | pre-release | All versions prior to |
| | | beta7 |
|----------------------------------+-------------+-----------------------|
| Asterisk Appliance Developer Kit | 0.x.x | All versions prior to |
| | | 0.8.0 |
|----------------------------------+-------------+-----------------------|
| s800i (Asterisk Appliance) | 1.0.x | All versions prior to |
| | | 1.0.3 |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Corrected In |
|------------------------------------------------------------------------|
| Product | Release |
|---------------+--------------------------------------------------------|
| Asterisk Open | 1.4.11, available from |
| Source | http://downloads.digium.com/pub/telephony/asterisk |
|---------------+--------------------------------------------------------|
| 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 | 0.8.0, available from |
| Appliance | http://downloads.digium.com/pub/telephony/aadk |
| Developer Kit | |
|---------------+--------------------------------------------------------|
| s800i | 1.0.3 |
| (Asterisk | |
| Appliance) | |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Links | http://bugs.digium.com/view.php?id=10421 |
| | |
| | http://bugs.digium.com/view.php?id=10418 |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| 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/asa/AST-2007-020.pdf and |
| http://downloads.digium.com/pub/asa/AST-2007-020.html. |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Revision History |
|------------------------------------------------------------------------|
| Date | Editor | Revisions Made |
|---------------------+------------------------+-------------------------|
| August 21, 2007 | russell@digium.com | Initial Release |
+------------------------------------------------------------------------+
Asterisk Project Security Advisory - AST-2007-020
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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