How to Use Aircrack-ng in Kali Linux

How to Use Aircrack-ng in Kali Linux

This ethical hacking guide explains how to use Aircrack-ng in Kali Linux for penetration testing of WiFi networks in cyber security.

Overview: Aircrack-ng

Aircrack-ng is a powerful suite of tools used for assessing and testing the security of wireless networks. It is a valuable tool for security professionals, penetration testers, and network administrators. However, it’s crucial to emphasize that the use of Aircrack-ng should be strictly limited to legitimate and authorized security assessments.

Unauthorized access to wireless networks is illegal and unethical. In this comprehensive guide, we’ll explain you how to use Aircrack-ng in Kali Linux for ethical and legal purposes.

Prerequisites: Kali Linux

Before you get started, ensure that you have the following prerequisites in place:

  1. Kali Linux: Aircrack-ng is pre-installed on Kali Linux. If you don’t have Kali Linux installed, you can download it from the official website and follow the installation instructions.
  2. Wireless Network Adapter: You’ll need a compatible wireless network adapter that supports monitor mode and packet injection. Some popular options include Alfa AWUS036NHA and TP-Link TL-WN722N. Ensure your adapter is recognized and supported by Kali Linux.

Using Aircrack-ng in Kali Linux

Below are the detailed steps on how to use Aircrack-ng in Kali Linux:

Step 1: Open a Terminal

Launch a terminal on your Kali Linux system. You’ll be running Aircrack-ng commands from the terminal, so having it open is essential for the entire process.

Step 2: Put Your Wireless Card in Monitor Mode

Monitor mode allows your wireless adapter to capture all wireless traffic in the vicinity. To put your wireless card in monitor mode, use the airmon-ng command. Replace wlan0 with the name of your wireless interface (it may vary):

Bash
sudo airmon-ng start wlan0

This command will create a new interface typically named wlan0mon. This interface is set up for monitoring and capturing packets.

Step 3: Scan for Wireless Networks

Use the airodump-ng command to scan for available wireless networks and capture information about them. Replace wlan0mon with your monitor mode interface:

Bash
sudo airodump-ng wlan0mon

You will see a list of nearby Wi-Fi networks, each identified by its BSSID (MAC address), ESSID (network name), channel, and encryption type. Take note of the network you want to assess, as you’ll need its BSSID and channel for further steps.

Step 4: Capture Data Packets

To capture data packets from the target network, open a new terminal window or tab and use the airodump-ng command again. This time, specify the BSSID and channel of the target network and choose an output file name:

Bash
sudo airodump-ng --bssid <BSSID> --channel <channel> -w <output-file-prefix> wlan0mon
  • <BSSID>: Replace this with the BSSID of the target network.
  • <channel>: Replace this with the channel number of the target network.
  • <output-file-prefix>: Choose a prefix for the output capture files (e.g., “mycapture”).

This command will capture packets related to the target network and save them in files with the prefix you provided.

Step 5: Deauthenticate a Client (Optional)

To expedite the process of capturing a WPA/WPA2 handshake (used for password cracking), you can deauthenticate a client device connected to the target network using the aireplay-ng command:

Bash
sudo aireplay-ng -0 1 -a <BSSID> -c <client-MAC> wlan0mon
  • <BSSID>: Replace this with the BSSID of the target network.
  • <client-MAC>: Replace this with the MAC address of a connected client.

This command sends deauthentication packets to the specified client, causing it to disconnect and potentially trigger a reconnection, which may result in capturing the WPA/WPA2 handshake.

Step 6: Capture the WPA/WPA2 Handshake

While monitoring the airodump-ng window from Step 4, wait for the “WPA handshake” message to appear in the top right corner. This indicates that a handshake has been captured.

Step 7: Crack the WPA/WPA2 Key

To crack the WPA/WPA2 passphrase, you’ll need a wordlist containing potential passwords. Kali Linux includes several wordlists in /usr/share/wordlists/. You can use the aircrack-ng command to perform the cracking:

Bash
sudo aircrack-ng -w /usr/share/wordlists/rockyou.txt -b <BSSID> <output-file.cap>
  • /usr/share/wordlists/rockyou.txt: Replace this with the path to your chosen wordlist.
  • <BSSID>: Replace this with the BSSID of the target network.
  • <output-file.cap>: Replace this with the name of the capture file (e.g., “mycapture-01.cap”).

Aircrack-ng will attempt to crack the passphrase using the provided wordlist. If successful, it will display the WPA/WPA2 key in the terminal.

Step 8: Analyze the Results

After successfully cracking the WPA/WPA2 key (if applicable), carefully analyze the results. Ensure that you document the key and any other relevant information for your security assessment report.

Bottom Line

Aircrack-ng is a valuable tool for assessing the security of wireless networks, but it should only be used for authorized and ethical purposes. Unauthorized access to wireless networks is illegal and unethical, and it’s crucial to obtain proper authorization before conducting any security assessments.

This comprehensive guide has provided you with the necessary steps to use Aircrack-ng in Kali Linux for legitimate security assessments, helping you identify and address vulnerabilities in wireless networks responsibly and ethically.

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