Buffer overflow en el voicemail con storage IMAP

Hace nada salió publicada la versión de Asterisk 1.4.13 que solucionaba varios fallos en la implementación del storage IMAP del voicemail.

Pocos días después, se ha revelado una nueva vulnerabilidad en el almacenamiento IMAP que podría producir un desbordamiento de buffer.

Este es el DSA de Digium:

Asterisk Project Security Advisory - AST-2007-022
+------------------------------------------------------------------------+
|      Product       | Asterisk                                          |
|--------------------+---------------------------------------------------|
|      Summary       | Buffer overflows in voicemail when using IMAP     |
|                    | storage                                           |
|--------------------+---------------------------------------------------|
| Nature of Advisory | Remotely and locally exploitable buffer overflows |
|--------------------+---------------------------------------------------|
|   Susceptibility   | Remote Unauthenticated Sessions                   |
|--------------------+---------------------------------------------------|
|      Severity      | Minor                                             |
|--------------------+---------------------------------------------------|
|   Exploits Known   | No                                                |
|--------------------+---------------------------------------------------|
|    Reported On     | October 9, 2007                                   |
|--------------------+---------------------------------------------------|
|    Reported By     | Russell Bryant >russell@digium.com<               |
|                    |                                                   |
|                    | Mark Michelson >mmichelson@digium.com<            |
|--------------------+---------------------------------------------------|
|     Posted On      | October 9, 2007                                   |
|--------------------+---------------------------------------------------|
|  Last Updated On   | October 10, 2007                                  |
|--------------------+---------------------------------------------------|
|  Advisory Contact  | Mark Michelson >mmichelson@digium.com<            |
|--------------------+---------------------------------------------------|
|      CVE Name      |                                                   |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Description | The function "sprintf" was used heavily throughout the   |
|             | IMAP-specific voicemail code. After auditing the code,   |
|             | two vulnerabilities were discovered, both buffer         |
|             | overflows.                                               |
|             |                                                          |
|             | The following buffer overflow required write access to   |
|             | Asterisk's configuration files in order to be exploited. |
|             |                                                          |
|             | 1) If a combination of the astspooldir (set in           |
|             | asterisk.conf), the voicemail context, and voicemail     |
|             | mailbox, were very long, then there was a buffer         |
|             | overflow when playing a message or forwarding a message  |
|             | (in the case of forwarding, the context and mailbox in   |
|             | question are the context and mailbox that the message    |
|             | was being forwarded to).                                 |
|             |                                                          |
|             | The following buffer overflow could be exploited         |
|             | remotely.                                                |
|             |                                                          |
|             | 2) If any one of, or any combination of the Content-type |
|             | or Content-description headers for an e-mail that        |
|             | Asterisk recognized as a voicemail message contained     |
|             | more than a 1024 characters, then a buffer would         |
|             | overflow while listening to a voicemail message via a    |
|             | telephone. It is important to note that this did NOT     |
|             | affect users who get their voicemail via an e-mail       |
|             | client.                                                  |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Resolution | "sprintf" calls have been changed to "snprintf" wherever  |
|            | space was not specifically allocated to the buffer prior  |
|            | to the sprintf call. This includes places which are not   |
|            | currently prone to buffer overflows.                      |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
|                           Affected Versions                            |
|------------------------------------------------------------------------|
|             Product              |   Release   |                       |
|                                  |   Series    |                       |
|----------------------------------+-------------+-----------------------|
|       Asterisk Open Source       |    1.0.x    | Unaffected            |
|----------------------------------+-------------+-----------------------|
|       Asterisk Open Source       |    1.2.x    | Unaffected            |
|----------------------------------+-------------+-----------------------|
|       Asterisk Open Source       |    1.4.x    | All versions prior to |
|                                  |             | 1.4.13                |
|----------------------------------+-------------+-----------------------|
|    Asterisk Business Edition     |    A.x.x    | Unaffected            |
|----------------------------------+-------------+-----------------------|
|    Asterisk Business Edition     |    B.x.x    | Unaffected            |
|----------------------------------+-------------+-----------------------|
|           AsteriskNOW            | pre-release | Unaffected            |
|----------------------------------+-------------+-----------------------|
| Asterisk Appliance Developer Kit |    0.x.x    | Unaffected            |
|----------------------------------+-------------+-----------------------|
|    s800i (Asterisk Appliance)    |    1.0.x    | Unaffected            |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
|                              Corrected In                              |
|------------------------------------------------------------------------|
|                 Product                  |           Release           |
|------------------------------------------+-----------------------------|
|           Asterisk Open Source           |           1.4.13            |
|------------------------------------------+-----------------------------|
|------------------------------------------+-----------------------------|
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
|        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-2007-022.pdf and          |
| http://downloads.digium.com/pub/security/AST-2007-022.html.            |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
|                            Revision History                            |
|------------------------------------------------------------------------|
|        Date        |          Editor           |    Revisions Made     |
|--------------------+---------------------------+-----------------------|
| October 9, 2007    | mmichelson@digium.com     | Initial Release       |
+------------------------------------------------------------------------+
Asterisk Project Security Advisory - AST-2007-022
Copyright (c) 2007 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.

Esperamos que se solucione pronto. Undecided

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