By exploiting network vulnerabilities to turn your mobile phone into a distracting device and disrupt small city networks, only twelve calls are required. Researchers have found a way to make ordinary mobile phones. In some cases, jammers may interfere with other calls, such as B. B. in a movie theater, classroom or meeting room. Phone calls are prohibited in some places. The prison will install jammers to prevent prisoners from claiming to be a prison. This "trouble" is not suitable for personal use, expensive and low energy consumption. Because they prevent emergency calls, they also pose security risks.
Now, computer scientists have shown that even business phones can be changed due to software changes. The team led by the Institute of Software Technology and Theoretical Computer Science exchanged software on mobile phones and took advantage of their weaknesses in the GSM radio standard. Computer scientists presented their research results at a security seminar and will develop an electronic device that can suppress cell phone signals.
Run optimized open source software on the backup phone. Therefore, they fool the radio antenna mast like a portable jammer and dip the frequency into a small part of the interference signal. Wrong calls may prevent text messages and calls from being sent to recipients in the area: forging people’s identities and answering questions with strange names. In the worst case, you can even block text messages. Because the radio station will send hundreds of square kilometers of status information before being called. This process is called paging. The lead author of the study said: "The call can be sent to all phones in the area." It contains an identification number that any phone can use to check whether it is on the device. "
However, the replacement phone will answer these questions and accept them, make calls and text messages faster than other phones. At the transmission tower, it seems that the actual receiver has been notified. But he didn't learn anything. In the best case, only the phone will be lost and no calls will be made. In the worst case, even text messages may be intercepted and read due to broken encryption and lack of authentication. So far, computer scientists have tested the GSM standard only more than 20 years ago, but have used many modern smartphones when necessary. In addition, the researchers said, this gap threatens the communication between machines and the future Internet of Things. New UMTS or LTE networks may also be vulnerable. Golde said: "Many GSM protocols are duplicated, and there are paging mechanisms in the third and fourth generation mobile standards." Similar attacks can be here. "But so far, there is a lack of correct hardware, especially software.
The computers used in their research are the same as those in Berlin before, and as long as 11 mobile phones can weaken the Berlin network. The scientist said: "You can respond to all paging requests and block the moving area." This affects the entire community. However, more calls need to be made during peak hours to meet the demands of more disruptive providers. Attackers can cover an area of 200 square kilometers on average in Berlin.
Mobile jammers are hard to find. Researchers say that only changes to the GSM standard can prevent such attacks. These will be difficult to implement. They complain that the industry refuses to add new standards to existing networks. Since more authentication and traffic can solve this vulnerability, the price will also be high. Since attacks not only target network operators and organizations, but also individual users, they may cause further financial losses when security breaches occur.