IMSI Catcher is an international mobile subscriber identity catcher. Basically, it is a phone eavesdropping device designed to intercept the traffic of mobile phones. This device can also track mobile phone users’ location data.
This catcher acts as a fake mobile tower between the real tower of the service provider and the target mobile phone. Intelligence agencies and law enforcement have been using this device in several countries. But the use of this device raises privacy concerns and significant civil liberty concerns.
What Is This Sophisticated Device?
The first VBTS or virtual base transceiver station was commercialized in 2003. The device is designed to identify the TMSI or temporary mobile subscriber identity and IMSI or international mobile subscriber identity of the closest GSM mobile devices.
And then the device going to intercept the mobile devices’ calls. Some more advanced devices are even able to detect the IMEI or international mobile equipment identity of mobile phones. This catcher device is a great help for search and rescue operations, especially to find missing persons.
Functions of The IMSI Catcher
This catcher device comes with at least three different functions. The first one is to identify an IMSI and the second function is to tap a mobile device. And the last function of this device is to detect passive IMSI. Learn more about the three functions of this catcher device below.
1. To identify an IMSI
Each mobile phone has specific requirements to optimize the reception of the phone. If around the mobile phone there are several base stations of the subscribed network operator, the mobile phone is going to choose one base station that has the strongest signal.
The catcher device is going to masquerade as one of the base stations. It makes the mobile phone within the defined radius receive the signal. The special identity request makes the catcher device able to force the IMSI transmission.
2. Tapping the mobile phone
The IMSI Catcher makes mobile phones around this device a target to the MITM or man-in-the-middle attack. The device will appear as s base station with a stronger signal that the mobile phone needs. The SIM helps the catcher to make the phone log into the GSM network as the mobile station.
The base station is going to choose the encryption mode but the catcher device will induce the mobile station so that it will not use encryption at all. This device will encrypt the plain traffic of text that comes from the mobile station before passing the text to the base station.
The targeted mobile device will get a signal but the user doesn’t know how to tell apart the device from the authentic infrastructure of the cell service provider. As the result, the device is going to take the data that the cell tower will get from the mobile phone.
3. To detect passive IMSI
What makes the passive IMSI and the active IMSI Catcher different is that the active catcher device will intercept the data that is being transferred, like web, mail, text, and spoke traffic between the cell tower and the endpoint. An active catcher will also intercept all data traffic and conversations.
The active catcher device will also send a signal to the endpoints with a lot of commands. The endpoints will respond by routing all data traffic and conversations after establishing a connection. It will create a route between the actual cell tower and the endpoints as long as the attacker wants.
How to use the passive catcher device? This passive catcher device will only detect the IMEI, IMSI, or TMSI of the endpoint. It will then send out a signal to the endpoints with one specific command only. Then the endpoints will respond and share the endpoint’s identifiers with the catcher device.
Quality Device for Legal Agents
One quality device that is going to replace the catcher device is the Hitech Interceptor. Government and intelligence agents can use this device to catch the network of the target cell phones. This device can intercept the conversations in the target phone.
It can record the calls automatically and listen to live calls. So many awesome features come along with this device. Instead of using the IMSI Catcher, check this Hitech Interceptor device at SMS Broadcaster.