For less than $500, you can build your own cellular intrusion detection system to detect malicious activity through your own local femtocell. Our team will show how we leveraged root access on a femtocell, reverse engineered the activation process, and turned it into a proof-of-concept cellular network intrusion monitoring system.
We leveraged commercial Home Node-Bs ("femtocells") to create a 3G cellular network sniffer without needing to reimplement the UMTS or CDMA2000 protocol stacks. Inside a Faraday cage, we connected smartphones to modified femtocells running Linux distributions and redirected traffic to a Snort instance. Then we captured traffic from infected phones and showed how Snort was able to detect and alert upon malicious traffic. We also wrote our own CDMA protocol dissector in order to better analyze CDMA traffic.