In Mr. Robot Season 2, Elliot Alderson from f/society compromises phone conversations of FBI using Femto-Cells. Before going to see how Elliot does the hack, let’s see what is Femto-Cell and difference between femtocell and cell phone booster/signal booster.
What is Femtocell?
Femtocell is a small device which is legal in some countries and illegal in some other countries. Femtocells are for those who don’t have good cell phone network or don’t have cell phone network at all in their areas. The coverage of femtocell cell is small i.e. only used for home/office or a single room.
Femtocells are connected to the Internet and the cellular operator’s network via cable modem or DSL router.
In India, cellphone carriers don’t sell the femtocells but in US, Verizon carrier sells them.
Read more about femtocell here.
These FemtoCells are designed to receive the cell signals and send it to cell phone carrier through Internet. Elliot Alderson wants to listen conversations of FBI, but to do this he needs to update the firmware of femtocell device to open a backdoor to listen FBI conversations.
An open source project OpenWRT provides firmware for IoT devices. Elliot was using OpenWRT.
Now the last step, connect the femtocell (modified using OpenWRT) to the Internet where FBI is working on E Corp headquarter. Angela Moss works for E Corp. She is friend of Elliot who installed femtocell on E Corp headquarter where FBI works.
Finally Elliot Alderson can record or divert all the calls of FBI officers/agents routed through this modified femtocell.
This is how we can use femtocells for different purposes and we can modify them using OpenWRT.
Few links for Mr. Robot series fans