Portable jammers can be devices of multiple shapes

Using network vulnerabilities to turn your phone into a distracting device and disrupt the small city network, you only need to make twelve calls. Researchers have found a way to make ordinary mobile phones. In some cases, jammers may interfere with other calls, such as BB in a movie theater, classroom or meeting room. Calls are prohibited in some places. The prison will install jammers to prevent prisoners from claiming to be. This “disease” is not suitable for personal use, is expensive and has low energy consumption. Because they prevent emergency calls, they also pose security risks.

Now, computer scientists have shown that even business phones can change 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 deceive 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 nearby recipients: forge identities and answer 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 allows each phone to check whether it is on the device. ”

However, the replacement phone answers these questions and accepts them, calls and texts faster than other phones. For the transmission tower, it appears that the actual recipient has been notified. But he didn’t learn anything. In the best case, only the phone is lost and there is no call. 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 only tested the GSM standard more than 20 years ago, but have used many modern smartphones when needed. 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. Gold said: “Many GSM agreements are duplicates.

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 moving areas.” This affects the entire community. However, more calls are required during peak hours to meet the demands of more disruptive providers. Attackers can cover an average of 200 square kilometers in Berlin.

Mobile jammers are difficult to find. Researchers say that only by changing the GSM standard can such attacks be prevented. These will be difficult to implement. They complained that the industry refused to include the new standard in the existing network. This will also be expensive because more authentication and traffic can solve this vulnerability. Since attacks not only target network operators and organizations, but also individual users, they may cause further financial losses when security breaches occur.