Listening to and protecting mobile phones

What are the options for listening to conversations on a mobile phone, how can you provide protection against attacks of this kind, and how can a subscriber determine that his telephone may be tapped? Due to the recent wave of espionage scandals, these issues become relevant again. Journalists turned to Ukrainian mobile operators with a request to explain how to behave to a subscriber in such cases.

It turned out to be striking that almost all the operators whom the journalists contacted simply could not give answers to the questions posed. The only company that agreed to help were representatives of MTS Ukraine. The operator Life :) didn’t give an answer to the sent request at all, and they replied to Kyivstar that they were not experts in such matters, and that such issues should be addressed to special public services (read, the Ministry of Internal Affairs, the Security Service of Ukraine, etc. ) The article below also used information on tapping mobile phones obtained from public sources.

How carriers protect their networks

When developing GSM technology, as well as at the stage of its implementation, all requirements from the state control were taken into account. bodies to the level of protection. It is precisely because of these requirements that in many countries of the world the sale and purchase of special equipment is prohibited, such as powerful encoders, crypto equipment, scramblers, as well as very secure technologies for public communication. But mobile operators themselves protect their radio channels using signal encryption methods. Encryption uses very sophisticated algorithms. Which cryptographic algorithm will be used for encryption is selected at the stage when a connection is established between the base station and the subscriber himself. The degree of probability of a leak of information about the subscriber from the operator’s equipment, as MTS employees assured reporters, that it is practically zero. Why to zero, we asked - and all because of the complexity and control over access to the facilities and equipment of the operator.

How can you “listen” to mobile phones

There are two methods of wiretapping of subscribers - the active method and the passive method. With passive listening, you need to use very expensive equipment and have specially trained workers. If you have money (read - a lot of money) on the “black market” you can purchase special systems, using which you can listen to the conversations of any subscriber within a radius of 500 meters. Ask why you need to have a lot of money? The answer is simple - the price of one such set starts from several hundred thousand Eurocurrencies. What such a kit looks like can be seen in the next photo. There are many sites on the network where you can familiarize yourself with the description and principle of operation of such kits and listening systems.


As manufacturers of such listening systems convince, their systems can track GSM conversations in real time, because the principle of operation of the equipment is based on access to the SIM card of a mobile subscriber, or directly to the database of the cellular operator itself. Although, if those who listen to you do not have such access, they can listen to all your conversations with some delay. The amount of delay depends on the level of encryption of the communication channel that one or another operator uses. Similar systems can also be mobile centers to provide listening and tracking the movement of objects.

The second method of wiretapping is to actively intervene directly on the authentication process and control protocols. For this, special mobile complexes are used. Such mobile systems, which, in fact, are a pair of specially modified phones and a laptop, despite their external simplicity and small size, are also an expensive pleasure - their price varies from a couple of tens of thousands to several hundred thousand US dollars. And again - only highly qualified specialists in the field of communications can work on such equipment.

An attack on a subscriber is carried out according to the following principle: since the complex is mobile and is located at a close distance to the subscriber - up to 500 meters - it “intercepts” signals to establish a connection and transfer data, replacing the base station of the operator. In fact, the complex itself becomes a "mediator bridge" between the nearest base station and the subscriber himself.

After “capturing” the desired mobile subscriber in this way, this complex can actually perform any control function over the intercepted channel: for example, connect the listener to any number necessary for those who listen, decrease the encryption algorithm, or completely disable this encryption for a particular communication session, etc. .d.

How similar a complex looks like is seen in the photo below.


As the experts shared, it’s impossible to determine 100% that the subscriber’s phone is being tapped at this moment. But, you can get indirect evidence that may indicate that there is such a possibility. In the recent past, some mobile models (namely, push-button phones) had in their functionality a special symbol-icon in the form of a lock. If the lock was closed, it means the signal is encrypted, and vice versa - if the lock is open ... well, you yourself understood everything.

But already in phones over the past 5-6 years, there is no such function ... A pity. Although, for some models of smartphones there are special applications that will signal the owner of the phone about the configuration of the settings used in the current communication session. One option is to notify the user of the mode in which his conversation is being transmitted - using encryption algorithms or openly. Listed below are a few of these applications:

Eagle security

It is one of the most powerful applications to protect your mobile from wiretapping. This program prevents any connections to false base stations. To determine the reliability of the station, the verification of signatures and station identifiers is used. In addition, the program independently monitors and remembers the location of all base stations and when it is detected that some base is moving around the city, or its signal disappears from its location from time to time - such a base is marked as false and suspicious and the application will notify the owner phone. Another useful feature of the program is the ability to show which of the applications and programs installed on the phone have access to the camcorder and microphone of your phone. There is also a function to disable (prohibit) access of any software you do not need to the camera.


This program differs from the previous one and its main function is to track any suspicious activity on the network, including when using SMS, which can be sent without the permission of the phone owner. The application real-time evaluates how secure your network is and what encryption algorithm is used at this moment and much more.

Android IMSI-Catcher Detector

This application also helps protect your smartphone from any connections to pseudo-databases. The only minus of this program is that you will not find it on Google Play and if you still want to install it, you will have to tinker with this procedure.


The CatcherCatcher program, like its counterparts above, detects false base stations that cybercriminals (or special services?) Use as intermediate “intermediary bridges” between the subscriber and the real base station.

And finally, experts also recommended using special applications to ensure the security of personal conversations and data, including encrypting your conversations. Similar analogues are the anonymous web browsers Orbot or Orweb, for example. There are also special programs that encrypt your phone calls, photos, and many already use secure messengers.

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