Thursday, March 8, 2018

Pentest via cellular network (II): Hologram Nova Global 2G/3G Modem


- Layout for this exercise (Smartphone and Raspberry Pi / SIM card / Modem):

1 - Hologram Nova Global 2G/3G Modem

- The modem Hologram Nova is a global 3G/2G cellular modem purpose-built for IoT and single board computers like the Raspberry Pi. 

- Paired with Hologram's CLI/Python SDK and global cellular network, the Nova is a simple plug-and-play modem for instant connectivity and secure data messaging.

- At the moment of writing this text, it can be bought online at a price of $49.

- Before the Nova modem can be operational the SIM must be activated (as done at previous exercise) so that it can gain access to the cellular network.

- The SIM card is inserted into the slot of the bottom of the Nova board, being careful that the Nova is not plugged-in at that moment:

- The Nova modem kit includes two quad-band flexible UFL anntenas, operating over 850/900/1900/2100 MHz bands.

- The larger black anntena is expected to provide better reception, though the yellow antenna has the benefit of fitting better due to its smaller size.

- The anntenas are attached pressing firmly down the gold UFL connector:

- Once the modem is operating correctly there are two LEDs (blue and red) providing feedback about what is going on inside the modem:

  • The blue LED represents whether the modem is on/off.
  • The red LED indicates the network status: off (no network detected), double blink(2G), rapid blink (3G), solid (connected)

2 - Hologram Python SDK

- The Python SDK and Hologram CLI are available on Github as open source.

- The Hologram Ptython SDK allows to connect and communicate the Hologram SIM card and the Nova USB modem with other IoT platforms for cellular connectivity:

- Installing the Hologram Python SDK to the Raspberry Pi device:


- On next exercises this Python SDK platform will be used abundantly:

3 - Checking the functionality of the modem

- First of all, let's check that Raspberry Pi detects the modem connected to one of its USB ports:

- Accessing available ports:

- hologram command has got several options:

- Detecting the type of modem:

- Printing the celullar network available:

- Printing the SIM card number used with the modem:

- Printing the signal strength:

- Printing the location:

4 - Sending and receiving SMS messages between a cellular phone and a modem

- Connecting the modem to the cellular network:

- A new interface ppp0 (point-to-point-protocol) is created:

- Checking the Internet connectivity let's see the huge replay delays of the pings, what it is understable in this kind of connection:

- Now, to send/receive SMS messages the cellular phone device key is required (available at the user Dashboard):

- Sending a message from the modem to the phone:

- The message is successfully received at the phone:

- Preparing the modem to receive SMSs:

- The phone answers:

- The phone receives the message:

- Finally the modem can be disconnected: