An attacker can implement an attack to disable the phone, and the user of the phone will not even guess. This will turn on the mobile device. The mobile device will not be able to receive incoming calls and SMS messages. On the phone screen, the link strength indicator will show the maximum value. To implement such an attack, the attackers do not contact the mobile operator. An attacker can implement such an attack with little effort. The only thing that gives out an attack is the rapid discharge of the phone's battery. The phone will drain quickly. Some phone models, when exposed to an attack, turn on the backlight of the phone, and it does not turn off while the attack is in progress.
With such attacks, threats are created in which possible disruptions in important negotiations or critical situations when a work phone is needed. Sometimes such attacks are only part of a larger plan for the user.
How do attackers implement such attacks?
The article on SMS spam describes how SMS services work. But few people know that such services can implement undocumented features. There is a special type of SMS messages - invisible SMS. Such SMS are not displayed on the phone screen and are not notified by the phone about its receipt. Such SMS is usually used by operators to check the existence of a mobile phone, but so that the user does not know about the request. Attackers can use this to implement a DoS attack on a mobile phone.
The implementation of a DoS attack through invisible SMS is implemented because SMS messages implement a signaling layer in the GSM network. Such messages clog the signaling channel. It is possible to create generators for sending invisible messages using HTTP or SMPP protocols. The basis of invisible-sms includes a simple scheme. Table 1 shows the format of the SMS message. With the help of these parts, an SMS is formed and sent to the SMS center.
Table 1.
