Netcat - 4. Lancer un shell distant | tutos fr

Introduction

This tutorial will guide you through using Netcat to launch a remote shell, specifically a Bash shell, allowing you to execute commands from a source machine. While this technique can be used for ethical purposes, such as remote management and automation, be aware that it is often associated with hacking activities. The aim here is to empower you with practical skills for everyday tasks in a secure environment.

Step 1: Install Netcat

Before you can use Netcat, ensure it is installed on your system.

• For Debian/Ubuntu systems, use the following command:

  sudo apt-get install netcat
  

• For Red Hat/CentOS systems, use:

  sudo yum install nc
  

Step 2: Prepare the Listening Machine

You need to set up a machine to listen for incoming connections.

1. Open your terminal.
2. Run the following command to start Netcat in listening mode on a specified port (e.g., 4444):

   nc -l -p 4444 -e /bin/bash
   

   • -l puts Netcat in listening mode.
   • -p specifies the port number.
   • -e allows you to execute a program (in this case, /bin/bash).

Step 3: Connect from the Source Machine

Now that the listening machine is set up, connect from your source machine.

1. Open the terminal on the source machine.
2. Use the following command to connect to the listening machine, replacing TARGET_IP with the IP address of the listening machine:

   nc TARGET_IP 4444
   

3. Upon a successful connection, you should have a shell prompt from the listening machine.

Step 4: Execute Commands Remotely

You can now execute commands directly on the listening machine from your source machine.

• Type any command, such as:

  ls
  

  This will list the files in the current directory of the listening machine.

Step 5: Close the Connection

To terminate the session, simply type exit in the command prompt of the remote shell or close the terminal on the source machine.

Practical Tips

• Always ensure you have permission to connect to the remote machine.
• Use secure networks to avoid unauthorized access.
• Be aware of firewall settings that may block your connection.

Conclusion

You have successfully learned how to use Netcat to launch a remote shell. This skill can be useful for various legitimate purposes, including server management and troubleshooting. Always remember to use these tools responsibly and ethically. Next, explore more advanced networking techniques or delve into other tools like SSH for secure remote access.