Summary:ASTERISK-14102: [patch] Early media bridged from caller to callee allows free calls
Reporter:Marcus Hunger (fnordian)Labels:
Date Opened:2009-05-11 06:15:28Date Closed:2011-07-26 14:18:52
Versions:Frequency of
Environment:Attachments:( 0) noincomingearlymedia.patch
german security press reported about this last week ( http://www.heise.de/security/Lauschangriff-in-VoIP-Netzen--/artikel/137297 ). The problem occurs on receiving a call and placing it to an user. Ringing and session progress data are bridged from the callee to the caller and that's good. The bad thing is that media-data from the caller is forwarded to the callee. This allows among other problems free calls. I learned that this might be wanted behavior e.g. for call centers, but it's not good for gateways.

There should be an option for Dial() to disable the forwarding of media-data to the callee during call-setup.
Comments:By: Tilghman Lesher (tilghman) 2009-05-11 16:11:00

You're talking about the design of early media, and it is functioning as designed.  While it may not function the way you'd like, it is not a security hole.  At best, this is a feature request requesting early media to be turned off.

By: Tilghman Lesher (tilghman) 2009-05-11 16:13:32

BTW, the best way to handle this is to use the second parameter of Dial, which specifies a time limit that the Dial is allowed to remain in a dialled state before the call will be considered to have failed.

By: Alec Davis (alecdavis) 2009-05-11 18:00:08

Early media to a SIP device seems to be broken in TRUNK.

Fills screen with the following and no audio.

May 7 22:07:43] WARNING[14412]: chan_sip.c:5922 sip_write: Asked to transmit frame type 64, while native formats is 0x8 (alaw)(8) read/write = 0x8 (alaw)(8)/0x8 (alaw)(8)

By: Marcus Hunger (fnordian) 2009-05-12 08:35:20

Ok, so let's declare it as a feature request. Not providing incoming early-media seems to be common in traditional pstn. So having the possibility to adopt to this behavior is reasonable, isn't it?

By: Joshua C. Colp (jcolp) 2009-05-12 08:36:34

alecdavis: Please file a separate issue for that.

By: Leif Madsen (lmadsen) 2009-06-10 13:04:40

Patch attached, so setting to 'Confirmed'.

By: Russell Bryant (russell) 2011-05-06 15:13:28

This feature is fine but someone will need to update the patch for trunk.

By: Leif Madsen (lmadsen) 2011-07-26 14:18:43.737-0500

Per the Asterisk maintenance timeline page at http://www.asterisk.org/asterisk-versions maintenance (bug) support for the 1.4 and 1.6.x branches has ended. For continued maintenance support please move to the 1.8 branch which is a long term support (LTS) branch. For more information about branch support, please see https://wiki.asterisk.org/wiki/display/AST/Asterisk+Versions

If this is still an issue, please open a new issue so it can be re-triaged appropriately. Thanks!