Blocking mobile communications within one cell hack

Hello, can you tell me is it real that guys Berlin’s Technological University were able to block all mobile communications within one cell in a GSM network with an old GSM phone? As far as I’ve understood, they have updated that phone’s firmware somehow, to block mobile calls. Is it possible and may work, or that’s just a fake? Many thanks in advance!

For starters, it should be mentioned that once these jamming devices are created, they are tested. With all the necessary tests such as transmitted frequencies, battery life and so on, the scrambling range is also tested. And these devices are most often tested on empty ground – this is why manufacturers are still demanding more reach than reality. It is obvious that the range is wider when there are no different buildings and concrete structures. But the fact is that most of us live in big cities and we are often surrounded by tall buildings. This explains why you should not be surprised if the blocking device you have can not block the signal from a phone located 20 meters away from you. There may be many reasons for this, but the most reasonable thing should be that the buildings make the beach smaller as obstacles.

Certainly, there are many types of signal jammers available on the market, so if you want to block any signal in a very wide range, then you will spend a small fortune on one of these devices. However, if you have a tight budget and will not be able to buy an expensive scrambling device, then you can get one of these low power devices. And they have a really decent work range, especially if your main goal is to block people in the surrounding areas. In this case, I think that a real range of about 5 meters will be enough, especially when you use it on the bus and you want people to be quiet for a few minutes. Then a signal jammer like this will definitely be useful.

What happens when you receive a call, or SMS? Your base station receives it first and then it looks for a device, which has to receive it. It simply sends queries to all of the connected phones and they have to answer. When a station gets a positive answer it redirects the call or SMS. But using smartphone vulnerabilities, we can block that process, by simply answering “yes” to all the queries, sent by a base station.

That’s how a simple GSM cell phone may start working as a high-power mobile phone jammer. There are no updates on is it possible to use that hack to intercept phone calls and messages, but technically it is possible. Those researchers also calculated that to create a powerful DDoS attack in German, they will need only 11 “updated” cell phones, that will be enough to block communications in the whole country