The situation has become even more desperate in recent days. The Russians are shelling cities indiscriminately killing women and children. They are now narrowing in on Kyiv and the mayor has imposed a two day curfew in anticipation of heavy fighting.

The cyber war against Russia is entering Round 2. The first round was won by the united front of world hackers who have successfully DDoSed nearly the entire internet in Russia. Russia has identified 17,000 IP addresses that were involved in probably the largest DoS attack in history. Good work! In addition, Russia is now trying to put into place a wall around its Internet to keep non-Russians out and circumvent the attacks.

This next round will likely involve street to street fighting. Russia is calling in mercenaries from Syria and Chechnya to conduct this urban warfare. This is because they have years of experience in form of brutal and inhuman warfare and they have no religious, language, ethnic or family ties to Ukraine enabling them to be even more ruthless than the Russian fighters who share ethnic, religious, language and families ties with the Ukrainians they are ordered to brutalize.

Now that the war has entered this street to street faze, we need to look at ways to interrupt and hinder the Putin war machine. One of the things that Ukrainians hackers can do is to jam their radio signals using the HackRF.

Military forces around the world use radio signals for variety of purposes including;

1. Land Communication

2. Aircraft communication

3. Location

4. Radar

5. Precision Guided missiles

6. Drones

In this tutorial, I’ll show you how the Russian military signals can be jammed.

What is Jamming?

Although the term may seem intuitive, there many ways to jam radio signals. In general, jamming is the deliberate blocking or interfering with radio signals. radio jamming has been used for decades by totalitarian regimes such as Russia and China to interfere with signals from other countries or transmitters sending information that they dislike. Signal jamming has a long military history including jamming communication, jamming drones, and jamming GPS among others.

If we tune our transmitter (HackRF in this case) to the same frequency and type of modulation, and with enough power we can “drown out” the signal coming to the receiver. Some of the most common types of jamming include sending random noise, a random pulse, stepped tones, a pulse and sweep through.

Step #1: Initial Steps

First, you will need a HackRF One. The RTL-SDR is inadequate for this task. Although the inexpensive RTL-SDR is an excellent receiver, it is ONLY a receiver. We need hardware that can transmit signals that can jam the Russian military signals. You can purchase one here and you can set it up in this tutorial here.

Next, you need an installation of Kali Linux (most other Linux distributions will work equally well). You will then need to install GNU Radio and gr-osmosdr. Fortunately, both are in the Kali repository so we can use the apt utility to install.

kali > sudo apt install gnuradio

kali > sudo apt install gr-osmosdr

 

Step #2: Identify the Frequencies Used by the Russian Military

The frequencies used by the Russian military are published online in numerous location including the one below.

https://wiki.radioreference.com/index.php/Category:Russia_Military_Frequencies

In addition, the adept radio jammer is recommended to simply listen to the frequencies around them to identify potential frequencies to jam.

Step #3 Jamming their Signals

osmosdr package we just downloaded has a utility named osmocom_siggen_nogui. This is a signal generator. As a signal generator, it has the capability of also jamming signals.

This signal generator is capable of producing various signals useful for jammimg including;

constant

sinusoid

uniform noise

Gaussian noise

Frequency sweep

GSM bursts

Two Tone

Let’s take a look at the help screen for this utility.

kali > osmocom_siggen_nogui -h

Now, check that your HackRF One is connected and functioning.

Kali > sudo hackrf_info

Now, we can begin the jamming! Select a frequency that the Russians are using for communication or other purposes and create a command similar to the following;

kali > osmocom_siggen_nogui -a hackrf -f 4182e6 –gaussian -x 2e6 -y 10 -v

This command uses our HackRF (-a hackrf) at 4182 kHz (one of Russian military communication frequencies) and uses a Gaussian noise (similar to white noise) jamming technique.

To apply this jamming on other communication frequencies, simply edit the frequency setting (in this case, 4182e6) and possibly the jamming technique. Different jamming techniques work better on different frequencies and communication protocols (GSM bursts, for instance, on GSM cellular communication).

Limitations

The primary limitation we must be concerned with is strength of signal. These are only effective if we are close to the receiver or can project a VERY strong signal. In addition, Russian military signals employ frequency hopping where the signal changes frequencies at a very rapid rate. In such cases, we may have employ multiple transceivers and target multiple frequencies (we don’t need to target all the frequencies as missing components will garble the signal adequately) or set the sending bandwidth very wide to cover the multiple frequencies.

Summary

Signal jamming has long and storied history in military tactics. Although some military communication is encrypted (many of the Russian shortwave communication is unencrypted and can be intercepted) this does not stop us from jamming it. It essence, jamming it keeps the signal from being received as sent as the receiver. That can have critical military implications.

Look for more tutorials here on using our HackRF to blunt the Russian attack in Ukraine.