Mobile network 4G suddenly changes to 2G? You should be careful

      It is undeniable that network technology has developed very rapidly and has become an indispensable part of our lives. But at the same time, it has also provided many criminals with opportunities to take advantage of. Recently, a user found that his mobile network suddenly changed from 4G to 2G, and received a large number of verification code messages, and finally the money in the network account was transferred away.

　　It is reported that these incidents are the result of criminals tampering with the user's network and using "SMS sniffing technology" to obtain the content of the mobile phone and steal money. In fact, sniffing technology is to use fake base stations and SMS interception devices to steal data on the user's mobile phone. At present, many people's mobile banking and payment platforms are bound to their own mobile phone numbers. Criminals use fake base stations to obtain nearby phone numbers. Then use the mobile phone number to log in to the financial website, and at the same time monitor the verification code sent back by the website through the air, so as to log in to the website and steal or transfer money.

　　Once sniffing technology is used, the signal will be downgraded from 4G to 2G. This is because the 2G communication protocol was formulated 30 years ago. Due to the limitations of the conditions at the time, the 2G protocol has a lot of loopholes. The most fundamental loophole is that the original 2G system did not verify the legitimacy of the base station, so as long as the base station parameter configuration is the same as the operator's base station parameter configuration, the mobile phone will think that the base station is legal and will establish a connection and communication with it.

　　Finally, when the victim is targeted by sniffing technology, he will receive a large number of text messages in a short period of time. However, in order not to arouse the victim's suspicion, criminals usually choose to act late at night or early in the morning. In this regard, turning off the phone at night or turning off the cellular network can effectively avoid attacks.