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[Full-disclosure] ASA-2007-013: IAX2 users can cause unauthorized data disclosure



>                     Asterisk Project Security Advisory - ASA-2007-013
> 
>    
> +----------------------------------------------------------------------------------+
>    |       Product        | Asterisk                                          
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |       Summary        | IAX2 users can cause unauthorized data disclosure 
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |  Nature of Advisory  | Unauthorized information disclosure               
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |    Susceptibility    | Remote authenticated sessions                     
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |       Severity       | Low                                               
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |    Exploits Known    | No                                                
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |     Reported On      | April 27, 2007                                    
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |     Reported By      | Tim Panton, Mexuar, <tim@xxxxxxxxxx>              
>         |
>    |                      |                                                   
>         |
>    |                      | Birgit Arkesteijn, Westhawk, 
> <birgit@xxxxxxxxxxxxxx>      |
>    
> |----------------------+-----------------------------------------------------------|
>    |      Posted On       | May 4, 2007                                       
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |   Last Updated On    | May 4, 2007                                       
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |   Advisory Contact   | kpfleming@xxxxxxxxxx                              
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |       CVE Name       | CVE-2007-2488                                     
>         |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    | Description | > From: Tim Panton <tim@xxxxxxxxxx>                        
>         |
>    |             |                                                            
>         |
>    |             | > Date: 27 April 2007 08:02:36 BDT                         
>         |
>    |             |                                                            
>         |
>    |             | > To: "Kevin P. Fleming" <kpfleming@xxxxxxxxxx>            
>         |
>    |             |                                                            
>         |
>    |             | > Subject: Possible IAX2 vulnerability (Minor)             
>         |
>    |             |                                                            
>         |
>    |             | >                                                          
>         |
>    |             |                                                            
>         |
>    |             | > We've stumbled on a bug in the way Asterisk's IAX2 
> handles text  |
>    |             |                                                            
>         |
>    |             | > frames.                                                  
>         |
>    |             |                                                            
>         |
>    |             | > I'm emailing you because it is a borderline security     
>         |
>    |             | vulnerability,                                             
>         |
>    |             |                                                            
>         |
>    |             | > and my                                                   
>         |
>    |             |                                                            
>         |
>    |             | > friends in the security world tell me that I should 
> notify the   |
>    |             |                                                            
>         |
>    |             | > vendor privately                                         
>         |
>    |             |                                                            
>         |
>    |             | > first. If you feel it isn't a security issue, let me 
> know and    |
>    |             | I'll                                                       
>         |
>    |             |                                                            
>         |
>    |             | > put it in mantis.                                        
>         |
>    |             |                                                            
>         |
>    |             | >                                                          
>         |
>    |             |                                                            
>         |
>    |             | > chan_iax2 assumes that the content of a text frame is a 
> null     |
>    |             |                                                            
>         |
>    |             | > terminated                                               
>         |
>    |             |                                                            
>         |
>    |             | > string (C style), and when time comes to forward the 
> string it   |
>    |             | uses                                                       
>         |
>    |             |                                                            
>         |
>    |             | > strlen                                                   
>         |
>    |             |                                                            
>         |
>    |             | > to determine the message length.                         
>         |
>    |             |                                                            
>         |
>    |             | >                                                          
>         |
>    |             |                                                            
>         |
>    |             | > If you send a frame without a 0 byte in it, Asterisk 
> forwards a  |
>    |             |                                                            
>         |
>    |             | > frame that                                               
>         |
>    |             |                                                            
>         |
>    |             | > includes the sent data and some extra (presumably heap) 
> data.    |
>    |             |                                                            
>         |
>    |             | >                                                          
>         |
>    |             |                                                            
>         |
>    |             | > If an attacker were lucky, the extra data could contain  
>         |
>    |             | something                                                  
>         |
>    |             |                                                            
>         |
>    |             | > interesting.                                             
>         |
>    |             |                                                            
>         |
>    |             | > Or conceivably it could cause a segmentation violation.  
>         |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    | Resolution | Asterisk code has been modified to enforce null-termination 
> of      |
>    |            | incoming text frames received by the IAX2 channel driver    
>         |
>    |            | (chan_iax2). When text frames are received without          
>         |
>    |            | null-termination, this may result in the last byte of data 
> in the   |
>    |            | frame being lost, if the IAX2 reception process does not 
> have space |
>    |            | in its receive buffer to add a null character.              
>         |
>    |            |                                                             
>         |
>    |            | As this vulnerability is of 'low' severity, it does not 
> justify new |
>    |            | releases of Asterisk solely for mitigating its impact. The 
> fix for  |
>    |            | this vulnerability has been committed to the Asterisk 
> Subversion    |
>    |            | source code repositories and is available to all users who 
> wish to  |
>    |            | upgrade to a prerelease checkout of the respective 
> development      |
>    |            | branch for their release series of Asterisk. All other 
> users can    |
>    |            | upgrade when the next regularly scheduled release of their 
> product  |
>    |            | is produced.                                                
>         |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    |                                Affected Versions                         
>         |
>    
> |----------------------------------------------------------------------------------|
>    |             Product              |   Release   |                         
>         |
>    |                                  |   Series    |                         
>         |
>    
> |----------------------------------+-------------+---------------------------------|
>    |       Asterisk Open Source       |    1.0.x    | has not been evaluated 
> as this  |
>    |                                  |             | release series is no 
> longer     |
>    |                                  |             | maintained              
>         |
>    
> |----------------------------------+-------------+---------------------------------|
>    |       Asterisk Open Source       |    1.2.x    | all releases prior to 
> 1.2.19    |
>    
> |----------------------------------+-------------+---------------------------------|
>    |       Asterisk Open Source       |    1.4.x    | all releases prior to 
> 1.4.4     |
>    
> |----------------------------------+-------------+---------------------------------|
>    |    Asterisk Business Edition     |    A.x.x    | all releases            
>         |
>    
> |----------------------------------+-------------+---------------------------------|
>    |    Asterisk Business Edition     |    B.x.x    | all releases prior to 
> B.2.1     |
>    
> |----------------------------------+-------------+---------------------------------|
>    |           AsteriskNOW            | pre-release | all releases prior to 
> and       |
>    |                                  |             | including Beta 5        
>         |
>    
> |----------------------------------+-------------+---------------------------------|
>    | Asterisk Appliance Developer Kit |    0.x.x    | all releases prior to 
> 0.4.1     |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    |                                   Corrected In                           
>         |
>    
> |----------------------------------------------------------------------------------|
>    |       Product        |                          Release                  
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    | Asterisk Open Source |          1.2.19 and 1.4.4 will be available from  
>         |
>    |                      | ftp://ftp.digium.com/pub/telephony/asterisk when 
> released |
>    
> |----------------------+-----------------------------------------------------------|
>    |  Asterisk Business   |    B.2.1, will be available from the Asterisk 
> Business    |
>    |       Edition        |    Edition user portal on http://www.digium.com 
> or via    |
>    |                      |          Digium Technical Support when released   
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |     AsteriskNOW      |  Beta 6, when available from 
> http://www.asterisknow.org,  |
>    |                      |   Beta 5 users can use 'System Update' in the 
> appliance   |
>    |                      | control panel to update their version of 
> AsteriskNOW when |
>    |                      |             Asterisk 1.4.4 has been released      
>         |
>    
> |----------------------+-----------------------------------------------------------|
>    |  Asterisk Appliance  |               0.4.1, will be available from       
>         |
>    |    Developer Kit     |   ftp://ftp.digium.com/pub/telephony/aadk when 
> released   |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    |        Links         | http://bugs.digium.com/view.php?id=9638           
>         |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    | 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://ftp.digium.com/pub/asa/ASA-2007-013.pdf.        
>         |
>    
> +----------------------------------------------------------------------------------+
> 
>    
> +----------------------------------------------------------------------------------+
>    |                                 Revision History                         
>         |
>    
> |----------------------------------------------------------------------------------|
>    |       Date        |           Editor            |         Revisions Made 
>         |
>    
> |-------------------+-----------------------------+--------------------------------|
>    |    May 4, 2007    |    kpfleming@xxxxxxxxxx     | initial release        
>         |
>    
> +----------------------------------------------------------------------------------+
> 
>                     Asterisk Project Security Advisory - ASA-2007-013
>                    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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