Hint: It’s really a cell tower. Engineer and artist Julian Oliver has created what he calls the “Stealth Cell Tower.” It’s an office printer modified to become a GSM base station.
“It brings the covert design practice of disguising cellular infrastructure as other things — like trees and lamp-posts — indoors, while mimicking technology used by police and intelligence agencies to surveil mobile phone users,” he states in his blog.
The device catches phones and sends them SMSs written to appear they are from someone the recipient knows — all without needing to know the phone number, according to Oliver.
With each response to the messages, a transcript is printed revealing the captured message sent, alongside the victim’s unique IMSI number and other identifying information. Sometimes the printer randomly calls phones in the environment. It plays a GSM encoding of an MP3 owned by the artist of Stevie Wonder’s “I Just Called To Say I Love You” when the call is answered.
The device is a Hewlett Packard Laserjet 1320 printer modified to contain and power components required implement a GSM 900 Base Station. These components include:
- BladeRF x40
- Raspberry Pi 3
- 2x short GSM omnidirectional antennas with magnetic base
- 2x SMA cable
- Cigarette-lighter-to-USB-charger circuit (converting 12-24v to 5v)
- 1x USB Micro cable (cut and soldered to output of USB charger)
- 1x USB A cable (cut and soldered to printer mainboard)
Oliver chose the HP Laserjet because it had unused space to host the components. No cables, other than one power cord, are visible on the exterior. The printer functions normally when connected via a USB cable to an electrical outlet.
November 3, 2016