Analyzing GSM with AirprobeGR GSM and Wireshark. The RTL SDR software defined radio can be used to analyze cellular phone GSM signals, using Linux based tools GR GSM or Airprobe and Wireshark. This tutorial shows how to set up these tools for use with the RTL SDR. Example Analysing GSM with RTL SDR Software Defined Radio. Decrypt P File Matlab Code' title='Decrypt P File Matlab Code' />Here is a screenshot and video showing an example of the type of data you can receive. You can see the unencrypted GSM packet information. You will not be able to see any sensitive information like voice or text message data since that part is encrypted. Decryption of messages that are not your own is very difficult, illegal and is not covered in this tutorial. First, you will need to find out at what frequencies you have GSM signals in your area. For most of the world, the primary GSM band is 9. MHz, in the USA it starts from 8. THE CAR HACKERS HANDBOOK. A Guide for the Penetration Tester. Craig Smith. MHz. If you have an E4. RTL SDR, you may also find GSM signals in the 1. MHz band for most of the world, and 1. MHz band for the USA. Open up SDRSharp, and scan around the 9. MHz or 8. 50 MHz band for a signal that looks like the waterfall image below. This is a non hopping GSM downlink signal. Using NFM, it will sound something like the example audio provided below. Note down the strongest GSM frequencies you can find. GSMNon. Hopping. Audio. Example. ogg. The rest of the tutorial is performed in Linux and we assume that you have basic Linux skills in using the terminal. For this tutorial we used Ubuntu 1. VMWare session. You can download the various ready to go Ubuntu VMWare images from here, and the free VMWare player from here. Note that virtual box is reported not to work well with the RTL SDR, as its USB bandwidth capabilities are poor, so VMWare player should be used. Install GR GSMThis tutorial is heavily based on the instructions from the gr gsm Git. Hub readme at https github. The easiest way to install gr gsm is to use Pybombs. Pybombs will automatically install gr gsm, and all the required dependencies including GNU Radio. Permission issue on JAR file can also cause NoClassDefFoundError in Java. If you are running your Java program in a multiuser operating system like Linux then you. Search and download open source project source codes from CodeForge. Novelics-Mentor-figure.jpg' alt='Decrypt P File Matlab Code' title='Decrypt P File Matlab Code' />Py. BOMBS sudo pybombs prefix init usrlocal a defaultprx sudo pybombs config defaultprefix defaultprx sudo pybombs recipes add gr recipes githttps github. Plug in your RTL SDR and connect it to your VM if necessary. Run grgsmlivemon by typing grgsmlivemon at the terminal. A new window should open. In the new window tune to a GSM downlink frequency which you determined while browsing in SDR and set the gain appropriately. Start Wireshark by using sudo wireshark k Y You may get an error when opening Wireshark but this can be ignored. You should now see the GSM data scrolling along in Wireshark. Old Method using Airprobe Click to ExpandInstall GNU Radio. You will need to install GNU Radio first in order to get RTL SDR to work. An excellent video tutorial showing how to install GNU Radio in Kali Linux can be found in this video shown below. Note that I had to run apt get update in terminal first, before running the build script, as I got 4. You can also use March Leechs install script to install the latest version of GNU Radio on any Linux OS. Installation instructions can be found here. I recommend installing from source to get the latest version. B8. Acp. 63. DA0. Update The new version 3. GNU Radio is not compatible with Air. Probe. You will need to install GNU Radio 3. However, neeo from the comments section of this post has created a patch which makes Air. Probe compatible with GNU Radio 3. To run it, place the patch file in your airprobe folder and then run patch p. Install Airprobe. Airprobe is the tool that will decode the GSM signal. I used multiple tutorials to get airprobe to install. First from this University of Freiberg tutorial, I used their instructions to ensure that the needed dependencies that airprobe requires were installed. Install Basic Dependenciessudo apt get y install git core autoconf automake libtool g python dev swig libpcap. Update Thanks to shyam jos from the comments section who has let us know that some extra dependencies are required when using the new Kali Linux 1. If youve skipped installing GNURadio because youre using the new Kali 1. SDR tools preinstalled, use the following command to install the extra required dependencies. Install libosmocoregit clone git git. Clone Airprobe. Now, I discovered that the airprobe git repository used in the University tutorial  berlin. From this reddit thread I discovered a more up to date airprobe git repository that does compile. Clone airprobe using the following git command. Now install gsmdecode and gsm receiver. Install gsmdecodecd airprobegsmdecode. Install gsm receivercd airprobegsm receiver. Testing Airprobe. Now, cd into to the airprobegsm receiversrcpython directory. First we will test Airprobe on a sample GSM cfile. Get the sample cfile which I found from this tutorial by typing into terminal. De. Modulationcapture9. M1. 12. cfile. Note The tutorial and cfile link is sometimes dead. I have mirrored the cfile on megaupload at this link. Place the cfile in the airprobegsm receiversrcpython folder. Now open wireshark, by typing wireshark into a second terminal window. Wireshark is already installed in Kali Linux, but may not be in other Linux distributions. Since Airprobe dumps data to a UDP port, we must set Wireshark to listen to this. Under Start in Wireshark, first set the capture interface to lo loopback, and then press Start. Then in the filter box, type in gsmtap. This will ensure only airprobe GSM data is displayed. Back in the first terminal that is in the python directory, type in. M1. 12. cfile. If everything installed correctly, you should now be able to see the sample GSM data in wireshark. Receive a Live Channel. To decode a live channel using RTL SDR type in terminal. A new window will pop up. Tune to a known non hopping GSM channel that you found earlier using SDRSharp by entering the Center Frequency. Then, click in the middle of the GSM channel in the Wideband Spectrum window. Within a few seconds some GSM data should begin to show constantly in wireshark. Type. gsmreceivertl. The s flag is used here to set the sample rate to 1. MSPS, which seems to work much better than the default of 1. MSPS as it seems that there should be only one GSM peak in the wideband spectrum window. Capturing a cfile with the RTL SDR Added 1. I wasnt able to find a way to use airprobe to capture my own cfile. I did find a way to capture one using. GNU Radio however. First save a rtlsdr. GSM signal frequency and g is the gain setting. Next, download this GNU Radio Companion GRC flow graph scroll all the way down for the link, which will convert the rtlsdr. Set the file source to the capture. Also, make sure that Repeat in the File Source block is set to No. Now execute the GRC flow graph by clicking on the icon that looks like grey cogs. This will create the capture. The flow chart will not stop by itself when its done, so once the file has been written press the red X icon in GRC to stop the flow chart running. The capture. cfile can now be used in airprobe. Ebay Auction Template For Fine Art. However, to use this cfile, I found that I had to use. Im not sure why, but a decimation rate of 6. I rtlsdrcapture. We dont cover how to decode the actual encrypted GSM data here, but this is possible to do with messages going to your own phone once you extract the encryption code for your sim card.