TUCoPS :: Asterisk :: bx3835.htm

Asterisk Traffic amplification in IAX2 firmware provisioning system
AST-2008-011: Traffic amplification in IAX2 firmware provisioning system
AST-2008-011: Traffic amplification in IAX2 firmware provisioning system



               Asterisk Project Security Advisory - AST-2008-011

   +------------------------------------------------------------------------+
   |      Product       | Asterisk                                          |
   |--------------------+---------------------------------------------------|
   |      Summary       | Traffic amplification in IAX2 firmware            |
   |                    | provisioning system                               |
   |--------------------+---------------------------------------------------|
   | Nature of Advisory | Traffic amplification attack                      |
   |--------------------+---------------------------------------------------|
   |   Susceptibility   | Remote unauthenticated sessions                   |
   |--------------------+---------------------------------------------------|
   |      Severity      | Critical                                          |
   |--------------------+---------------------------------------------------|
   |   Exploits Known   | No                                                |
   |--------------------+---------------------------------------------------|
   |    Reported On     | July 18, 2008                                     |
   |--------------------+---------------------------------------------------|
   |    Reported By     | Tilghman Lesher < tlesher AT digium DOT com >     |
   |--------------------+---------------------------------------------------|
   |     Posted On      | July 22, 2008                                     |
   |--------------------+---------------------------------------------------|
   |  Last Updated On   | July 22, 2008                                     |
   |--------------------+---------------------------------------------------|
   |  Advisory Contact  | Tilghman Lesher < tlesher AT digium DOT com >     |
   |--------------------+---------------------------------------------------|
   |      CVE Name      | CVE-2008-3264                                     |
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   | Description | An attacker may request an Asterisk server to send part  |
   |             | of a firmware image. However, as this firmware download  |
   |             | protocol does not initiate a handshake, the source       |
   |             | address may be spoofed. Therefore, an IAX2 FWDOWNL       |
   |             | request for a firmware file may consume as little as 40  |
   |             | bytes, yet produces a 1040 byte response. Coupled with   |
   |             | multiple geographically diverse Asterisk servers, an     |
   |             | attacker may flood an victim site with unwanted firmware |
   |             | packets.                                                 |
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   | Workaround | The only device which used this firmware upgrade          |
   |            | procedure was the IAXy ATA device, and the last firmware  |
   |            | upgrade was more than 18 months ago. It is unlikely that  |
   |            | any IAXy devices in use today still need the last         |
   |            | firmware upgrade. Therefore, deleting the firmware image  |
   |            | from the directory where it is served from and sending a  |
   |            | reload event to the Asterisk server is sufficient to      |
   |            | purge the firmware image from the Asterisk server's       |
   |            | memory. An Asterisk server which is unable to serve out   |
   |            | the requested firmware image will reply to any such       |
   |            | request with a much smaller REJECT packet, which is       |
   |            | smaller than even the FWDOWNL packet.                     |
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   | Resolution | This firmware download procedure has been disabled by     |
   |            | default in Asterisk. If you should still need to upgrade  |
   |            | IAXys in the field, there is an option 'allowfwdownload'  |
   |            | which can be enabled. However, due to the reasons         |
   |            | specified on the Workaround section, it is recommended    |
   |            | that you leave this option disabled and enable it only on |
   |            | secure internal networks when an IAXy is initially        |
   |            | provisioned.                                              |
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   |                           Affected Versions                            |
   |------------------------------------------------------------------------|
   |             Product              |   Release   |                       |
   |                                  |   Series    |                       |
   |----------------------------------+-------------+-----------------------|
   |       Asterisk Open Source       |    1.0.x    | All versions          |
   |----------------------------------+-------------+-----------------------|
   |       Asterisk Open Source       |    1.2.x    | All versions prior to |
   |                                  |             | 1.2.30                |
   |----------------------------------+-------------+-----------------------|
   |       Asterisk Open Source       |    1.4.x    | All versions prior to |
   |                                  |             | 1.4.21.2              |
   |----------------------------------+-------------+-----------------------|
   |         Asterisk Addons          |    1.2.x    | Not affected          |
   |----------------------------------+-------------+-----------------------|
   |         Asterisk Addons          |    1.4.x    | Not affected          |
   |----------------------------------+-------------+-----------------------|
   |    Asterisk Business Edition     |    A.x.x    | All versions          |
   |----------------------------------+-------------+-----------------------|
   |    Asterisk Business Edition     |    B.x.x    | All versions prior to |
   |                                  |             | B.2.5.4               |
   |----------------------------------+-------------+-----------------------|
   |    Asterisk Business Edition     |    C.x.x    | All versions prior to |
   |                                  |             | C.1.10.3              |
   |----------------------------------+-------------+-----------------------|
   |           AsteriskNOW            | pre-release | All versions          |
   |----------------------------------+-------------+-----------------------|
   | Asterisk Appliance Developer Kit |    0.x.x    | All versions          |
   |----------------------------------+-------------+-----------------------|
   |    s800i (Asterisk Appliance)    |    1.0.x    | All versions prior to |
   |                                  |             | 1.2.0.1               |
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   |                              Corrected In                              |
   |------------------------------------------------------------------------|
   |                   Product                   |         Release          |
   |---------------------------------------------+--------------------------|
   |            Asterisk Open Source             |          1.2.30          |
   |---------------------------------------------+--------------------------|
   |            Asterisk Open Source             |         1.4.21.2         |
   |---------------------------------------------+--------------------------|
   |          Asterisk Business Edition          |         B.2.5.4          |
   |---------------------------------------------+--------------------------|
   |          Asterisk Business Edition          |         C.1.10.3         |
   |---------------------------------------------+--------------------------|
   |          Asterisk Business Edition          |         C.2.0.3          |
   |---------------------------------------------+--------------------------|
   |         s800i (Asterisk Appliance)          |         1.2.0.1          |
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   |        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://downloads.digium.com/pub/security/AST-2008-011.pdf and | 
| http://downloads.digium.com/pub/security/AST-2008-011.html | 
   +------------------------------------------------------------------------+

   +------------------------------------------------------------------------+
   |                            Revision History                            |
   |------------------------------------------------------------------------|
   |      Date       |       Editor       |         Revisions Made          |
   |-----------------+--------------------+---------------------------------|
   | July 22, 2008   | Tilghman Lesher    | Initial release                 |
   |-----------------+--------------------+---------------------------------|
   | July 22, 2008   | Tilghman Lesher    | Revised C.1 version numbers     |
   +------------------------------------------------------------------------+

               Asterisk Project Security Advisory - AST-2008-011
              Copyright (c) 2008 Digium, Inc. All Rights Reserved.
  Permission is hereby granted to distribute and publish this advisory in its
                           original, unaltered form.


TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2024 AOH