Technology Tutorials

Story

I bought two Pine a64 2Gb boards when there was a liquidation at my local electronics store half a year ago. Since then they were lying around and collecting dust, mainly because they are a lot more difficult to use than the raspberry pi. I finally found a good use for one. I installed a 12 $ rtlsdr dongle (RTL2832U), so I can listen to the frequencies in the air from 500 kHz up to 1.75 GHz. This means the device receives data from radio, planes, satellites, garage doors and also some mobile communication. One of the most interesting things was to see how smartphones communicate with towers. The following instructions seem pretty long but it is easier than you think and most is copy and paste code.

Installation of Armbian and the RTL-SDR dongle

1. Download the latest Armbian OS (based on Ubuntu) for your device. You should pick the one with graphical desktop. Then on a Windows PC you can unpack it using the free tool 7zip and install the .img file on a microSD card with Win32DiskImager.

2. Hook up the pine64 on a screen with an hdmi cable. Add a usb mouse and keyboard.
Now plug in the microSD and and power the device up. The first boot will take a bit longer then usual.
Eventually, you will be asked to sign in with a username and password. This is for armbian “root” and “1234”.
Now you are prompted to create a new password for the root account and you need to create a normal user with username and password. If you want to access the command line of the pine64 from a windows pc you can use SSH with Putty. Great, now all the basic stuff is done.

3. When you plug in the rtlsdr dongle you should be able to see it in the list created with:

lsusb

.
For me it looks like this:

Bus 001 Device 003: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

In my case “0bda” is the vendor identification and “2838” is the product number.
Run

sudo nano /etc/udev/rules.d/20.rtlsdr.rules

to write a new file with the content:

SUBSYSTEM=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2838", GROUP="adm", MODE="0666", SYMLINK+="rtl_sdr"

You need to insert the vendor id and product number of your device if it is different than my example. This should ensure that the rtl-sdr is available for the pine.

Installation of GNU Radio

1. In the terminal, update the system with:

sudo apt-get update && sudo apt-get upgrade

.

2. First, you can run

sudo apt install gnuradio

to install GNU Radio, which is a software that lets you process information from software radios. Next, you install the rtl-sdr tools. Note that some of the steps can take very long to compute on the Pine a64.

git clone https://github.com/balint256/gr-baz.git
cd gr-baz
mkdir build
cd build
sudo apt-get install cmake
sudo apt-get install gnuradio-dev
cmake ..
make
sudo make install
sudo ldconfig

Installation of Gr-Gsm

1. The installation of gr-gsm follows the instructions from osmocom. First, you need to install a few modules, that are required for the software:

sudo apt-get update && \
sudo apt-get install -y \
cmake \
autoconf \
libtool \
pkg-config \
build-essential \
python-docutils \
libcppunit-dev \
swig \
doxygen \
liblog4cpp5-dev \
python-scipy \
python-gtk2 \
gnuradio-dev \
gr-osmosdr \
libosmocore-dev

2. When this is done, you can install gr-gsm, which is required to see gsm communication:

 cd ~
git clone https://git.osmocom.org/gr-gsm
cd gr-gsm
mkdir build
cd build
cmake ..
mkdir $HOME/.grc_gnuradio/ $HOME/.gnuradio/
cd ~/gr-gsm/build
make
sudo make install
sudo ldconfig

Next, you need some Python modules to run the IMSI-catcher script:

sudo apt-get install python-numpy python-scipy python-scapy

Then, you can download the scripts:

git clone https://github.com/Oros42/IMSI-catcher

Run the following line to update the mobile provider list:

sudo apt-get install python-bs4
python IMSI-catcher/mcc-mnc/update_codes.py

3. Let the fun part begin. You need to have a graphical desktop in front of you. Open two terminal windows. In the first one you enter

grgsm_scanner

to see on what frequencies there are towers around you. Then, start to listen to one of those frequencies with:

grgsm_livemon -f 'YOURFREQUENCY'M

.
e.g.

grgsm_livemon -f 948.2M

In the second window you start to receive the processed data in the form of a list with IMSI numbers, phone providers and countries. To get this run inside the IMSI-catcher folder:

python simple_IMSI-catcher.py

There you go. I hope you have as much fun as I had with this tool 🙂 More information can be found here.

Hint: If you want the data to be directly stored in a textfile, use:

python simple_IMSI-catcher.py >> yourfile.txt

Have you ever seen a demonstration, where a hacker opened a garage door or triggered a wireless doorbell from distance? The Universal Radio Hacker (URH) could be a good choice for such a scenario. However, you can also do more productive things, like connecting incompatible devices to your computer or smart home.

Instructions

Note: In case, that you need to set up rtl-sdr or you get an error, make sure that you check my previous tutorials in the RTL-SDR series in order to have the same starting point.

1. Install the required packages for URH:

sudo apt-get install python3-numpy python3-psutil python3-zmq python3-pyqt5 g++ libpython3-dev python3-pip cython3

2. Install the setup-tools in case you don^t have them already:

sudo apt-get install python3-setuptools

3. Then, you can install URH with PIP:

sudo pip3 install urh

4. To run the program, you can open a terminal on the desktop and type:

urh

Make sure the RTL-SDR is selected in the options.

5. Have fun, I will document my experiences in future. You can also find a series of tutorials on YouTube.

Gqrx is a graphical tool that visualizes radio signals in the spectrum. One of the easiest applications is, to tune to the frequency of a local FM or AM radio station and listen to the music. Assuming that you followed the airplane tracking tutorial, the installation is simple.

1. Run each line separately to add the repositories that are required:

sudo add-apt-repository -y ppa:bladerf/bladerf

sudo add-apt-repository -y ppa:myriadrf/drivers

sudo add-apt-repository -y ppa:myriadrf/gnuradio

sudo add-apt-repository -y ppa:gqrx/gqrx-sdr

sudo apt-get update

2. Install the program:

sudo apt-get install gqrx-sdr

3. Now, you can run the program with

gqrx-sdr

or by clicking on it in the startmenu-section internet. The first time you run it, you need to select an input device. For me it was the recommended one. In the window under ‘file>Start DSP’ you can start the waterfall and the audio.