# Course #370: Introduction to Multimon-ng in Kali Linux
## Section 1: Installation and Configuration of Multimon-ng
### What is Multimon-ng?
Multimon-ng is a powerful tool used in the realm of digital forensics and pentesting for decoding various digital packet transmissions. It is particularly effective for decoding signals from various digital modes, such as POCSAG, FLEX, and others. As a versatile and robust tool, it can transform the way professionals understand and interact with digital signals.
### Installation on Kali Linux
**Step 1: Update Your System**
Before installing any package, it is always a good practice to ensure that your system is up to date. Open the terminal in Kali Linux and run the following command:
"`bash
sudo apt update && sudo apt upgrade -y
"`
**Step 2: Install Multimon-ng**
Multimon-ng is included in the Kali Linux repositories. You can install it using the `apt` package manager. Run the following command:
"`bash
sudo apt install multimon-ng -y
"`
**Step 3: Verify the Installation**
To verify that Multimon-ng has been successfully installed, you can check the version of the application. Run:
"`bash
multimon-ng –version
"`
This should display the version number of Multimon-ng, confirming that it is installed and ready for use.
### Configuration of Multimon-ng
Multimon-ng uses various input source types. It can operate with either live radio signals received through a software-defined radio (SDR) or input from a captured file.
#### Setting Up for Live Input
1. **Install Required Software:**
For live monitoring, you typically need additional software like `gnuradio` and `gqrx` or a compatible SDR hardware. Install Gnu Radio with:
sudo apt install gnuradio gqrx-sdr
2. **Connect Your SDR Device:**
Make sure your SDR device is connected to your computer. For example, if you're using a USB SDR like RTL-SDR, plug it in and ensure it's recognized.
3. **Set Up Audio Input:**
Depending on your installation, you may need to configure the audio input settings to ensure Multimon-ng can process the incoming signals.
### Usage of Multimon-ng
#### Running Multimon-ng
To use Multimon-ng, you can run it directly from the terminal. The basic syntax for running Multimon-ng is as follows:
"`bash
multimon-ng -a
"`
– `
– `
##### Example: Decoding POCSAG
1. **Capture Live POCSAG Signals:**
First, you need to tune into the frequency transmitting POCSAG signals. You can do this using `gnuradio` or another SDR application.
2. **Running Multimon-ng:**
Once you've tuned your device, you can begin capturing and decoding. For example, if you were using a device like RTL-SDR, your command might look like this (assuming your RTL-SDR device is `/dev/stdin`):
rtl_fm -f 433.920M -s 22050 -r 48000 – | multimon-ng -a POCSAG_TEXT -t –
This command tells `rtl_fm` to tune to 433.920 MHz and pipe the output directly into `multimon-ng`.
#### Real-world Use Cases
1. **Emergency Services Monitoring:**
Multimon-ng can be employed by digital forensics investigators to monitor emergency services communications. For instance, a security professional can decode POCSAG messages from pagers to understand the operations of local emergency services during a critical incident.
2. **Wireless Security Analysis:**
In a penetration testing scenario, Multimon-ng can assist in the analysis of security protocols in wireless systems. By capturing and decoding management frames from wireless networks, pentesters can identify vulnerabilities and misconfigurations.
3. **Data Recovery:**
In a digital forensics setting, Multimon-ng can help recover data from compromised systems where the data transmission has been logged. By decoding the captured transmissions, valuable insights may be recovered.
### Detailed Technical Explanations
#### Modes Supported by Multimon-ng
Multimon-ng is capable of decoding various digital modes. Here’s a breakdown of some of the most common modes:
– **POCSAG:** A paging protocol commonly used for sending messages to pagers.
– **FLEX:** Another paging protocol utilized by some of the more modern paging systems.
– **DMTF:** Dual Tone Multi Frequency, often used in telephony.
– **FSK:** Frequency Shift Keying, a modulation scheme for transmitting digital signals.
Each of these modes operates on a different set of protocols and requires specific configurations for successful decoding.
### External Resources
For further reading and advanced configurations, you can refer to the following resources:
1. [Multimon-ng Official Documentation](https://github.com/EliasOenal/multimon-ng)
2. [Kali Linux Official Documentation on Wireless Attacks](https://www.kali.org/docs/wireless/)
3. [GNU Radio Documentation](https://wiki.gnuradio.org/index.php/Main_Page)
### Code Examples
Here are some common command examples formatted in Markdown code blocks for inclusion in WordPress:
#### Example: POCSAG Decoding
"`bash
rtl_fm -f 433.920M -s 22050 -r 48000 – | multimon-ng -a POCSAG_TEXT -t –
"`
#### Example: FLEX Decoding
"`bash
rtl_fm -f 462.550M -s 22050 -r 48000 – | multimon-ng -a FLEX -t –
"`
#### Example: Decoding from a File
"`bash
multimon-ng -a POCSAG_TEXT -t /path/to/captured.wav
"`
### Conclusion
Multimon-ng is an essential tool for any pentester or digital forensics investigator working with digital signals. Its flexibility and range of supported modes make it invaluable for monitoring, decoding, and analyzing various digital communications. By mastering installation, configuration, and practical usage, you can harness the power of Multimon-ng to enhance your security assessments and investigations.
—
Made by pablo rotem / פבלו רותם