Advisory Text :  

Asterisk Project Security Advisory - AST-2008-002

+-----------------------------------------------------------------------

-+
| Product | Asterisk
|

|--------------------+--------------------------------------------------

-|
| Summary | Two buffer overflows in RTP Codec Payload
|
| | Handling
|

|--------------------+--------------------------------------------------

-|
| Nature of Advisory | Exploitable Buffer Overflow
|

|--------------------+--------------------------------------------------

-|
| Susceptibility | Remote Unauthenticated Sessions
|

|--------------------+--------------------------------------------------

-|
| Severity | Critical
|

|--------------------+--------------------------------------------------

-|
| Exploits Known | No
|

|--------------------+--------------------------------------------------

-|
| Reported On | March 11, 2008
|

|--------------------+--------------------------------------------------

-|
| Reported By | Mu Security Research Team
|

|--------------------+--------------------------------------------------

-|
| Posted On | March 18, 2008
|

|--------------------+--------------------------------------------------

-|
| Last Updated On | March 18, 2008
|

|--------------------+--------------------------------------------------

-|
| Advisory Contact | Joshua Colp <jcolp (at) digium (dot) com
[email concealed]> |

|--------------------+--------------------------------------------------

-|
| CVE Name | CVE-2008-1289
|

+-----------------------------------------------------------------------

-+

+-----------------------------------------------------------------------

-+
| Description | Two buffer overflows exist in the RTP payload
handling |
| | code of Asterisk. Both overflows can be caused by an
|
| | INVITE or any other SIP packet with SDP. The request
may |
| | need to be authenticated depending on configuration
of |
| | the Asterisk installation.
|
| |
|
| | The first overflow is caused by sending a payload
number |
| | that surpasses the programmed maximum payload number
of |
| | 256. This causes an invalid memory write outside of
the |
| | buffer. While this does not allow the attacker to
write |
| | arbitrary data it does allow the attacker to write a
0 |
| | to other memory locations.
|
| |
|
| | The second overflow is caused by sending more than 32
|
| | RTP payloads. This causes a buffer on the stack to
|
| | overflow allowing the attacker to write values
between 0 |
| | and 256 (the maximum payload number) to memory
locations |
| | after the buffer.
|

+-----------------------------------------------------------------------

-+

+-----------------------------------------------------------------------

-+
| Resolution | Two fixes have been added to check the provided data
to |
| | ensure it does not exceed static buffer sizes.
|
| |
|
| | When removing internal information regarding an RTP
|
| | payload the given payload number will now be checked
to |
| | make sure it does not exceed the maximum acceptable
|
| | payload number.
|
| |
|
| | When reading RTP payloads from SDP a maximum limit of
32 |
| | in total will be enforced. Any further RTP payloads
will |
| | be discarded.
|

+-----------------------------------------------------------------------

-+

+-----------------------------------------------------------------------

-+
| 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
1.4.18.1 |
| | | and 1.4.19-rc3
|

|----------------------------+---------+--------------------------------

-|
| Asterisk Open Source | 1.6.x | All versions prior to
|
| | | 1.6.0-beta6
|

|----------------------------+---------+--------------------------------

-|
| Asterisk Business Edition | A.x.x | Unaffected
|

|----------------------------+---------+--------------------------------

-|
| Asterisk Business Edition | B.x.x | Unaffected
|

|----------------------------+---------+--------------------------------

-|
| Asterisk Business Edition | C.x.x | All versions prior to
C.1.6.1 |

|----------------------------+---------+--------------------------------

-|
| AsteriskNOW | 1.0.x | All versions prior to 1.0.2
|

|----------------------------+---------+--------------------------------

-|
| Asterisk Appliance | SVN | All versions prior to
Asterisk |
| Developer Kit | | 1.4 revision 109386
|

|----------------------------+---------+--------------------------------

-|
| s800i (Asterisk Appliance) | 1.1.x | All versions prior to
1.1.0.2 |

+-----------------------------------------------------------------------

-+

+-----------------------------------------------------------------------

-+
| Corrected In
|

|-----------------------------------------------------------------------

-|
| Product | Release
|

|---------------+-------------------------------------------------------

-|
| Asterisk Open | 1.4.18.1/1.4.19-rc3/1.6.0-beta6, available from
|
| Source |
http://downloads.digium.com/pub/telephony/asterisk |

|---------------+-------------------------------------------------------

-|
| Asterisk | C.1.6.1
|
| Business |
|
| Edition |
|

|---------------+-------------------------------------------------------

-|
| AsteriskNOW | 1.0.2, available from http://www.asterisknow.org/
|
| |
|
| | Current users can update using the system update
|
| | feature in the appliance control panel.
|

|---------------+-------------------------------------------------------

-|
| Asterisk | Asterisk 1.4 revision 109386. Available by
performing |
| Appliance | an svn update of the AADK tree.
|
| Developer Kit |
|

|---------------+-------------------------------------------------------

-|
| s800i | 1.1.0.2
|
| (Asterisk |
|
| 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://downloads.digium.com/pub/security/AST-2008-002.pdf and
|
| http://downloads.digium.com/pub/security/AST-2008-002.html
|

+-----------------------------------------------------------------------

-+

+-----------------------------------------------------------------------

-+
| Revision History
|

|-----------------------------------------------------------------------

-|
| Date | Editor | Revisions Made
|

|------------------+--------------------+-------------------------------

-|
| 2008-03-18 | Joshua Colp | Initial Release
|

+-----------------------------------------------------------------------

-+

Asterisk Project Security Advisory - AST-2008-002
Copyright (c) 2008 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory
in its
original, unaltered form.