The number of IMSI-catchers (rogue cell towers) has been steadily increasing in use by hackers and governments around the world. Rogue cell towers, which can be as small as your home router, pose a large security risk to anyone with a phone. If in range, your phone will automatically connect to the rogue tower with no indication to you that anything has happened. At that point, your information passes through the rogue tower and can leak sensitive information about you and your device. Currently, there are no easy ways to protect your phone from connecting to a rogue tower (aside from some Android apps which are phone specific and require root access).

This project demonstrates how you can create a rogue cell tower detector using a Raspberry Pi and a SIM 900 module. The detector can identify rogue towers and triangulate their location. The demonstration uses a SIM 900 GSM module to fingerprint each cell tower and determine the signal strength of each tower relative to the detector.