Conducting Wireless Attacks with Aircrack-ng: A Comprehensive Guide

Wireless networks are often the target of cybersecurity attacks due to their ubiquitous nature and, sometimes, weak security measures. Aircrack-ng is a powerful suite of tools designed to assess and improve the security of wireless networks. In this article, we will take an in-depth look at how to conduct wireless attacks using Aircrack-ng on Kali Linux. This guide is perfect for technical students and professionals who are eager to advance their cybersecurity skills.

For those looking to deepen their knowledge, we recommend enrolling in our Kali Linux in Cyber Security course at Indian Cyber Security Solutions.

1. Introduction to Aircrack-ng

Aircrack-ng is a comprehensive suite of tools that includes a packet sniffer, WEP and WPA/WPA2-PSK cracker, hash capture tools, and more. It is widely used in penetration testing to assess the security of Wi-Fi networks.

Key Components of Aircrack-ng:

• Airmon-ng: Enables monitor mode on wireless interfaces.
• Airodump-ng: Captures packets and provides details about the networks.
• Aireplay-ng: Injects packets into a network to create traffic.
• Aircrack-ng: The main tool used to crack WEP and WPA/WPA2-PSK keys.

2. Installing and Configuring Aircrack-ng

Step 1: Verify Installation

Aircrack-ng comes pre-installed with Kali Linux. You can verify its presence by running:

aircrack-ng --help        

If it is not installed, use the following command to install it:

sudo apt-get install aircrack-ng        

Step 2: Identify Your Wireless Interface

Identify the wireless interface card (WIC) on your system by running:

ifconfig        

Look for an interface with names like wlan0 or wlan1.

Step 3: Enable Monitor Mode

Monitor mode is essential for capturing packets on a wireless network. Enable it using:

sudo airmon-ng start wlan0        

Replace wlan0 with your interface name. This will start a virtual interface, typically named wlan0mon.

3. Capturing Packets with Airodump-ng

Step 1: Start Packet Capture

Once monitor mode is enabled, you can start capturing packets from nearby wireless networks using:

sudo airodump-ng wlan0mon        

This command will display all the wireless networks in range along with key details like BSSID (MAC address), channel, encryption type, and more.

Step 2: Capture Targeted Network Traffic

To focus on a specific network, use the following command:

sudo airodump-ng --bssid [target_BSSID] -c [channel_number] -w [output_file] wlan0mon        

• target_BSSID: Replace with the BSSID of the target network.
• channel_number: The channel number on which the target network is operating.
• output_file: The name of the file where captured data will be saved.

4. Deauthentication Attack with Aireplay-ng

A deauthentication attack is used to force connected clients to disconnect from the network, which can help capture a WPA/WPA2 handshake.

Step 1: Identify Connected Clients

With Airodump-ng running, identify clients connected to the target network. Look for stations under the BSSID of your target.

Step 2: Launch the Deauthentication Attack

Once you have identified a client, execute the following command:

sudo aireplay-ng --deauth 10 -a [target_BSSID] -c [client_MAC] wlan0mon        

• target_BSSID: The BSSID of the target network.
• client_MAC: The MAC address of the client you want to deauthenticate.

This command sends deauthentication packets to the client, forcing it to reconnect to the network.

5. Capturing the WPA/WPA2 Handshake

The goal of deauthenticating a client is to capture the WPA/WPA2 handshake, which is crucial for cracking the network’s password.

Step 1: Capture the Handshake

With Airodump-ng still running and the deauthentication attack in progress, look for a WPA handshake in the top right corner of the Airodump-ng output. It will indicate that a handshake has been successfully captured.

Step 2: Verify the Handshake

Once captured, you can verify the handshake capture with the following command:

aircrack-ng [output_file]-01.cap        

This command will check if the WPA handshake was captured successfully.

6. Cracking the Password with Aircrack-ng

Once you have captured the handshake, you can attempt to crack the network’s password using a dictionary attack.

Step 1: Use a Wordlist

Aircrack-ng requires a wordlist to attempt to crack the password. Kali Linux includes a popular wordlist called rockyou.txt. Use it as follows:

sudo aircrack-ng -w /usr/share/wordlists/rockyou.txt -b [target_BSSID] [output_file]-01.cap        

• target_BSSID: The BSSID of the target network.
• output_file: The file containing the captured handshake.

Step 2: Wait for Cracking to Complete

Aircrack-ng will now attempt to crack the password by comparing the captured handshake with each password in the wordlist. The process can take time depending on the wordlist size and complexity of the password.

7. Advanced Techniques with Aircrack-ng

Step 1: Using Custom Wordlists

You can create custom wordlists tailored to your target using tools like Crunch:

crunch 8 12 abcdefghijklmnopqrstuvwxyz0123456789 -o custom_wordlist.txt        

This command generates a wordlist of passwords with lengths between 8 and 12 characters, using lowercase letters and numbers.

Step 2: Performing a WPS Attack

WPS (Wi-Fi Protected Setup) attacks are another method for cracking Wi-Fi passwords. Use Reaver to perform a brute-force attack on the WPS PIN:

sudo reaver -i wlan0mon -b [target_BSSID] -vv        

Reaver will attempt to crack the WPS PIN and retrieve the WPA/WPA2 passphrase.

8. Securing Your Wireless Network

Understanding these attacks also highlights the importance of securing your own wireless networks:

• Disable WPS: Disable WPS on your router to prevent WPS attacks.
• Use Strong Passwords: Use complex, non-dictionary passwords for your wireless networks.
• Regularly Monitor Network Traffic: Use tools like Airodump-ng to monitor for unauthorized activity on your network.

Conclusion

Conducting wireless attacks with Aircrack-ng on Kali Linux is a fundamental skill for cybersecurity professionals. By following this guide, you can effectively test the security of wireless networks and understand how attackers may exploit vulnerabilities. To further enhance your skills, consider enrolling in our Kali Linux in Cyber Security course at Indian Cyber Security Solutions, where you will receive hands-on training and expert guidance.