[asterisk-dev] Dialstring vulnerability and switch =

[Russell Bryant]

On 02/17/2010 03:14 AM, Olle E. Johansson wrote:
> In our sample extensions.conf, there are a few switches included in the default context. How are these affected?
> I think it should be mentioned as an issue in the README too...

Let's go over the types of switches and how they might be affected ...

1) IAX2 Switch

This effectively lets you do a remote dialplan lookup.  If it matches, 
it will send the call over IAX2.  The remote dialplan will need to be 
secured just like the local dialplan.

2) Loopback switch

This is just a weird way to do local dialplan lookups.  Securing the 
dialplan with this switch in use is no different than we have discussed 
so far.

3) DUNDi Switch

This is another remote dialplan lookup method, but amongst a peer to 
peer network.  Similar to IAX2, the only problem that exists is when the 
call is forwarded over SIP, IAX2, etc. to a remote box and dialplan 
executes.  The remote dialplans must be secured.

4) Realtime Switch

This allows dialplan lookups from a realtime backend.  The application 
arguments in the database must be secured just as if they were written 
in extensions.conf.


In summary, I don't think the usage of a switch introduces any new 
elements to the problem.  The end result is still a vulnerability when 
you're accepting VoIP calls via some method, and the dialplan must be 
secure.  Am I missing anything?

-- 
Russell Bryant
Digium, Inc. | Engineering Manager, Open Source Software
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
www.digium.com -=- www.asterisk.org -=- blogs.asterisk.org