A new generation of GSM eavesdropping devices

For several weeks now, a new generation of GSM eavesdropping systems has become market-ready. The further development of this already known eavesdropping method benefits from the increasing miniaturization of GSM-based communication systems. It is currently possible to accommodate a GSM chipset including a micro-SIM card reader unit in a volume of 10 x 10 x 3 mm. This chipset includes a complete GSM protocol stack with all data transmission functions. This miniaturization makes it possible, for example, to fit a completely GSM-based eavesdropping system into the USB plug of an inconspicuous smartphone charging cable.

The SIM card holder can be easily covered with a cap that can be fixed with glue if necessary, so that it can no longer be removed without damage.

Integrated into a suitable power-carrying object, such as a USB plug, charging cable, table clock, calculator, multi-power plug, and much more, the manipulated object can no longer be distinguished from a normal one.

This hidden GSM unit can be called at any time and from anywhere in the world to secretly listen to the surroundings within a radius of up to about 10 m. Additionally, the device can be programmed via SMS to automatically dial a definable number when a certain sound level is reached. The GSM unit can also transmit LBS data of the cell tower and thus locate the user. The accuracy depends on the cell tower density and ranges from 100 m in the city to several kilometers in the countryside.

For several reasons, the effectiveness of such a GSM bug is considered very high: for example, it would be relatively easy to replace an existing USB charging cable with the manipulated cable or to plug a USB connector unnoticed into the PC. Likewise, the same can of course also be specifically deployed with a target person. As long as this tiny GSM listening device is powered, it remains active, even for years.

X-ray images show that this highly miniaturized GSM unit features a professionally designed circuit board originating from the mass production of the mobile phone industry. It requires little imagination to realize that such an extremely miniaturized eavesdropping unit can be parasitically integrated into almost any electrical device or machine with a power supply. Although the circuit can be detected with highly advanced and high-resolution stationary X-ray equipment, this approach would require extensive expert knowledge about the specific device being examined. In practice, these highly integrated circuits can no longer be reliably detected or distinguished from regular circuits using simple X-ray devices.