[asterisk-users] asterisk security....again

[Ricardo Carvalho]

Probably, you are receiving INVITE attacks from some tool like sipvicious.
You should rearange your network to cover some inportant security issues.

The IP address of you server can be revealed in some unincrypted SIP
signaling of some call through the Internet to/from your server's client, or
simply by your client SRV record in the DNS, if you added it to his DNS.

Probably your network is exposed to the Internet. To address those
situations, you can use a distinct VLAN to address SIP phones and you also
can use port security at the switching ports where you connect your ATAs and
phones. You should also deliver with tagging (802.1Q) that VLAN to those
ATAs and phones. This should protect you from inside sniffers.
This VLAN should just communicate with the DMZ where you should have your
asterisk server and between those two networks you should only open the
needed ports - for a common SIP infrastructure you should open UDP 5060 and
the specified UDP range shown in rtp.conf file for the media to pass. Phones
VLAN should not communicate directlly with the world, just in the outbound
direction if you like.

Regards,
Ricardo Carvalho.






On Mon, Feb 28, 2011 at 10:33 AM, Rizwan Hisham <rizwanhasham at gmail.com>wrote:

> Hi all,
> The problem I have been experiencing since last month is that some of my
> customers are getting calls with "Asterisk <Unknown>" caller id. Most of
> them in the middle of the night. And my asterisk server has no record of
> these calls. The customers were getting irritated as you can imagine. I
> guessed the only way to receive incoming calls by by-passing the
> registration server is thru sip-uri calls directly to customers. I have
> updated the customers atas to not accept any calls from sources other than
> the registration server. Thats all fine now. But the question is how can
> anyone know the direct sip uri addresses of our customers.
>
> My guess is that someone has been sniffing my server's sip traffic. In that
> case what should i do to get rid of the sniffers?
>
> If you think there is another reason for that then please tell me even if
> you dont have the solution.
>
> Thanks
>
> --
> Best Ragards
> Rizwan Qureshi
> VoIP/Asterisk Engineer
> Axvoice Inc.
> V: +92 (0) 3333 6767 26
> E: rizwanhasham at gmail.com
> W: www.axvoice.com
>
>
> --
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