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June 7, 2005
 

Low-cost, internet phone service lacks protection

The next wave of telecommunication is almost upon us, but it lacks the proper protections, says Ram Dantu, an assistant professor of computer science and engineering at UNT. The next big thing seems to be VoIP, or voice over internet protocols. These systems combine the mobility of cell phones and the low-cost use of internet service, in contrast to the current system of dedicated circuits from calling party to called party. Though the advantages of new IP services are great, so are their vulnerabilities.

"VOIP stands for voice over internet protocol- basically, how you actually transport voice on the internet. The internet is run on a protocol called IP, whereas the existing telephone networks run on circuit switch networks. Internet is used for several different services, not just voice; it is used for data, for video. So all different services are going to run as internet, so there will be service degradation as well as the [lack of] security aspect." .wav file (42 seconds)

Dantu explains a 'denial of service attack', one of the most common assaults that hackers use to debilitate IP phones. 

"Denial of service attack means that there will be somebody continuously sending unwanted traffic to you, either to your IP phone sitting on your desk, or your IP phone sitting in your house, or a PBX studies telephone switch in an enterprise like UNT. If they keep sending a large amount of traffic, then the particular device becomes unusable." .wav file (28 seconds)

VoIP cannot be protected by traditional firewall or computer security systems. Dantu explains why running calls through an IP system is so vulnerable to spoofing, a technique used to gain unauthorized access to computers or phone systems.

"Since the voice is run on an internet infrastructure, the voice stream goes through several routers and switches and different servers, there is the possibility of several people in the middle having the chance to listen to the voice or spoof the voice. Since the cost of sending information on the internet is almost free, people from other countries like Singapore, India or China could actually generate spam onto the voice network." .wav file (36 seconds)

In order to secure IP phone systems and conversations, researchers have developed systems that recognize and accept or deny callers based on their "reputation."

"In our lab at UNT we are actually doing research in preventing these denial of service and spamming attacks. We are using almost entirely different techniques to stop this, because we are based on the trust and reputation of the other party. So we actually have trust and reputation levels assigned dynamically to the other calling parties. What it means is that, if your grandmother calls, to you her reputation is a lot higher than somebody who is an anonymous caller, whose reputation is a lot lower. For example, if you get a call from john something and you don't know him, but you know your friend knows him, that means his reputation is higher than compared to [an anonymous person]."  .wav file (51 seconds)

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