Toll Free Calls Fraud on Internet

[omendieta77]

Hi folks,

I don't know if you have been going through this problem.

Many clients that have acces to Internet through ADSL service are having their phone/voice lines busy because an external user through Internet takes their lines to make world wide phone calls, charging this cost to the ADSL user.

The fraud is related to the way the hacker takes the gateway that belongs to another user in another country and provides phone services.

PLease let me know if you have heard about this. Is there any vulnerability?

Thanks in advance.

Orlando

[shikamarunara]

You need to get in touch with the IXC or whoever is providing the SIP telephony service. They will have a CDR of all calls and the IP address that the call originated from. The reason that these fraudsters are able to make these calls is because there is basically no real authentication at the IXC SIP peer. It should require a username, password, and a hardcoded static IP address (in other words, not just any host should be able to connect to the SIP proxy and generate calls, only hosts from a specific static IP address.) If you can't do that, there will pretty much always be fraud use. Change to a telephony provider that has some security.

HTH - don't forget to rate posts!

-Shikamaru