[security at asterisk.org: [asterisk-users] AST-2009-001: Information leak in IAX2 authentication]

Diana Cionoiu diana at null.ro
Thu Jan 8 20:51:34 UTC 2009


What about Yate 2?

Diana

Tzafrir Cohen wrote:
> yey, we get to push yet another version of Asterisk.
>
> Though I feel a bit uncomfortable about the fix: we leak (albeit very
> little) information about previous authentication to the next
> authentication. Can this actually help a slow scan?
>
> I'd rather wait a bit with this one.
>
> ----- Forwarded message from Asterisk Security Team <security at asterisk.org> -----
>
> To: asterisk-users at lists.digium.com
> From: Asterisk Security Team <security at asterisk.org>
> Date: Thu, 08 Jan 2009 13:28:55 -0600
> Subject: [asterisk-users] AST-2009-001: Information leak in IAX2
> 	authentication
> Reply-To: Asterisk Users Mailing List - Non-Commercial Discussion <asterisk-users at lists.digium.com>
>
>                Asterisk Project Security Advisory - AST-2009-001
>
>    +------------------------------------------------------------------------+
>    |       Product        | Asterisk                                        |
>    |----------------------+-------------------------------------------------|
>    |       Summary        | Information leak in IAX2 authentication         |
>    |----------------------+-------------------------------------------------|
>    |  Nature of Advisory  | Unauthorized data disclosure                    |
>    |----------------------+-------------------------------------------------|
>    |    Susceptibility    | Remote Unauthenticated Sessions                 |
>    |----------------------+-------------------------------------------------|
>    |       Severity       | Minor                                           |
>    |----------------------+-------------------------------------------------|
>    |    Exploits Known    | Yes                                             |
>    |----------------------+-------------------------------------------------|
>    |     Reported On      | October 15, 2008                                |
>    |----------------------+-------------------------------------------------|
>    |     Reported By      | http://www.unprotectedhex.com                   |
>    |----------------------+-------------------------------------------------|
>    |      Posted On       | January 7, 2009                                 |
>    |----------------------+-------------------------------------------------|
>    |   Last Updated On    | January 7, 2009                                 |
>    |----------------------+-------------------------------------------------|
>    |   Advisory Contact   | Tilghman Lesher < tlesher AT digium DOT com >   |
>    |----------------------+-------------------------------------------------|
>    |       CVE Name       | CVE-2009-0041                                   |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    | Description | IAX2 provides a different response during authentication |
>    |             | when a user does not exist, as compared to when the      |
>    |             | password is merely wrong. This allows an attacker to     |
>    |             | scan a host to find specific users on which to           |
>    |             | concentrate password cracking attempts.                  |
>    |             |                                                          |
>    |             | The workaround involves sending back responses that are  |
>    |             | valid for that particular site. For example, if it were  |
>    |             | known that a site only uses RSA authentication, then     |
>    |             | sending back an MD5 authentication request would         |
>    |             | similarly identify the user as not existing. The         |
>    |             | opposite is also true. So the solution is always to send |
>    |             | back an authentication response that corresponds to a    |
>    |             | known frequency with which real authentication responses |
>    |             | are returned, when the user does not exist. This makes   |
>    |             | it very difficult for an attacker to guess whether a     |
>    |             | user exists or not, based upon this particular           |
>    |             | mechanism.                                               |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    | Resolution | Upgrade to revision 167259 of the 1.2 branch or 167260 of |
>    |            | the 1.4 branch or one of the releases noted below.        |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    |                           Affected Versions                            |
>    |------------------------------------------------------------------------|
>    |          Product           | Release |                                 |
>    |                            | Series  |                                 |
>    |----------------------------+---------+---------------------------------|
>    |    Asterisk Open Source    |  1.2.x  | All version prior to 1.2.31     |
>    |----------------------------+---------+---------------------------------|
>    |    Asterisk Open Source    |  1.4.x  | All versions prior to           |
>    |                            |         | 1.4.23-rc4                      |
>    |----------------------------+---------+---------------------------------|
>    |    Asterisk Open Source    |  1.6.x  | All versions prior to           |
>    |                            |         | 1.6.0.3-rc2                     |
>    |----------------------------+---------+---------------------------------|
>    |      Asterisk Addons       |  1.2.x  | Not affected                    |
>    |----------------------------+---------+---------------------------------|
>    |      Asterisk Addons       |  1.4.x  | Not affected                    |
>    |----------------------------+---------+---------------------------------|
>    |      Asterisk Addons       |  1.6.x  | Not affected                    |
>    |----------------------------+---------+---------------------------------|
>    | Asterisk Business Edition  |  A.x.x  | All versions                    |
>    |----------------------------+---------+---------------------------------|
>    | Asterisk Business Edition  |  B.x.x  | All versions prior to B.2.5.7   |
>    |----------------------------+---------+---------------------------------|
>    | Asterisk Business Edition  | C.1.x.x | All versions prior to C.1.10.4  |
>    |----------------------------+---------+---------------------------------|
>    | Asterisk Business Edition  | C.2.x.x | All versions prior to C.2.1.2.1 |
>    |----------------------------+---------+---------------------------------|
>    |        AsteriskNOW         |   1.5   | Not affected                    |
>    |----------------------------+---------+---------------------------------|
>    | s800i (Asterisk Appliance) |  1.2.x  | All versions prior to 1.3.0     |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    |                              Corrected In                              |
>    |------------------------------------------------------------------------|
>    |                  Product                   |          Release          |
>    |--------------------------------------------+---------------------------|
>    |            Asterisk Open Source            |          1.2.31           |
>    |--------------------------------------------+---------------------------|
>    |            Asterisk Open Source            |         1.4.22.1          |
>    |--------------------------------------------+---------------------------|
>    |            Asterisk Open Source            |          1.6.0.3          |
>    |--------------------------------------------+---------------------------|
>    |         Asterisk Business Edition          |          B.2.5.7          |
>    |--------------------------------------------+---------------------------|
>    |         Asterisk Business Edition          |         C.1.10.4          |
>    |--------------------------------------------+---------------------------|
>    |         Asterisk Business Edition          |         C.2.1.2.1         |
>    |--------------------------------------------+---------------------------|
>    |         s800i (Asterisk Appliance)         |           1.3.0           |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    |                                Patches                                 |
>    |------------------------------------------------------------------------|
>    |                               URL                               |Branch|
>    |-----------------------------------------------------------------+------|
>    |http://downloads.digium.com/pub/security/AST-2009-001-1.2.diff   |1.2   |
>    |-----------------------------------------------------------------+------|
>    |http://downloads.digium.com/pub/security/AST-2009-001-1.4.diff   |1.4   |
>    |-----------------------------------------------------------------+------|
>    |http://downloads.digium.com/pub/security/AST-2009-001-1.6.0.diff |1.6.0 |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    |        Links        | http://code.google.com/p/iaxscan/                |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    | 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-2009-001.pdf and          |
>    | http://downloads.digium.com/pub/security/AST-2009-001.html             |
>    +------------------------------------------------------------------------+
>
>    +------------------------------------------------------------------------+
>    |                            Revision History                            |
>    |------------------------------------------------------------------------|
>    |      Date       |         Editor         |       Revisions Made        |
>    |-----------------+------------------------+-----------------------------|
>    | 2009-01-07      | Tilghman Lesher        | Initial release             |
>    +------------------------------------------------------------------------+
>
>                Asterisk Project Security Advisory - AST-2009-001
>               Copyright (c) 2009 Digium, Inc. All Rights Reserved.
>   Permission is hereby granted to distribute and publish this advisory in its
>                            original, unaltered form.
>
>
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