WiFi Penetration Testing with NodeMCU ESP8266 and PhiSiFi Framework

Table of Contents

• Project Overview
• Hardware Requirements
• Environment Setup
• Firmware Installation
• Attack Execution
• Advanced Configurations
• Defense and Mitigation

Project Overview

The NodeMCU ESP8266 is a powerful, low-cost WiFi development board that can be weaponized for wireless security testing. Using the PhiSiFi firmware, this $5 device becomes capable of performing deauthentication attacks, evil twin AP deployments, and credential harvesting - all while validating captured passwords against the actual network.

Hardware Requirements

The beauty of this project lies in its simplicity - minimal hardware components are required:

Environment Setup

Setting up the development environment is straightforward with the Arduino IDE:

Arduino IDE Configuration

Download and install Arduino IDE, then configure it for ESP8266 development:

# Add ESP8266 Board Manager URL in File > Preferences:
http://arduino.esp8266.com/stable/package_esp8266com_index.json

# Install ESP8266 boards:
# Tools > Board > Boards Manager > Search "ESP8266" > Install

# Board Settings:
# Board: NodeMCU 1.0 (ESP-12E Module)
# Upload Speed: 115200
# CPU Frequency: 80 MHz

Firmware Installation

The PhiSiFi firmware provides an intuitive web interface for WiFi security testing. Here's how to get it running:

Downloading PhiSiFi

Navigate to the PhiSiFi GitHub repository: https://github.com/p3tr0s/PhiSiFi

Download the repository as a ZIP file or clone it. You'll find the main .ino file in the downloaded folder.

Opening in Arduino IDE

Instead of editing through command line, simply:

1. Open Arduino IDE
2. Navigate to File > Open
3. Select the PhiSiFi.ino file from the downloaded repository
4. The entire project will load with all dependencies

Firmware Customization

Before flashing, customize the access point settings directly in the Arduino IDE:

// Customizable AP settings in the .ino file
const char* ap_ssid = "PhiSiFi_Test";        // Change your AP name here
const char* ap_password = "password123";      // Change your AP password here
const char* hostname = "phisifi";

// Network configuration
IPAddress local_IP(192,168,4,1);
IPAddress gateway(192,168,4,1);
IPAddress subnet(255,255,255,0);

Flashing Process

Connect your NodeMCU via USB and flash the firmware:

# Verify settings in Arduino IDE:
# Port: Select appropriate COM port (Windows) or /dev/ttyUSB* (Linux)
# Board: NodeMCU 1.0 (ESP-12E Module)
# Upload Speed: 115200

# Click Upload button - process takes 30-60 seconds

Attack Execution

Once flashed and powered on, the NodeMCU creates its own access point. The interface is intuitive and requires no technical expertise to navigate.

Initial Connection

# Connect to the PhiSiFi access point:
# SSID: PhiSiFi_Test (or your custom name)
# Password: password123 (or your custom password)
# Auto-redirect to: http://192.168.4.1

Network Reconnaissance

The web interface automatically scans and displays all 2.4GHz networks within range, showing:

• SSID: Network names
• Channel: Operating frequencies
• Signal Strength: RSSI values
• Encryption Type: WPA2/WPA3/Open
• Client Count: Connected devices

Deauthentication Attack

The deauth feature disconnects all clients from target networks by sending spoofed deauthentication frames:

Evil Twin Attack

The evil twin creates an identical access point to capture credentials:

Attack Workflow:

1. Target Selection: Choose high-value network
2. AP Cloning: Creates identical SSID
3. Simultaneous Deauth: Disconnects legitimate users
4. Captive Portal: Presents convincing login page
5. Password Validation: **PhiSiFi actually validates captured passwords against the real network**

Credential Harvesting and Validation

One of PhiSiFi's advanced features is its ability to validate captured passwords:

# Validation Process:
# 1. User enters password in captive portal
# 2. PhiSiFi attempts connection to real AP with credentials
# 3. Validates if password is correct
# 4. Stores result with validation status
# 5. Notifies attacker of successful captures

After the attack completes, reconnect to your PhiSiFi AP to view captured and validated credentials through the web interface.

Advanced Configurations

Since this was my first project in this domain, I've since advanced the concept significantly. Here are some improvements for more sophisticated testing:

Dual-Device Setup

For enhanced effectiveness, consider using two NodeMCU devices:

Alternative Firmware Options

# Advanced firmware options:
# 1. ESP8266 Deauther - Multi-attack platform
# 2. WiFi Pineapple firmware ports
# 3. Custom Arduino implementations
# 4. Marauder firmware for enhanced features

Range Extension

For professional testing, consider hardware modifications:

• External Antennas: Increase range to 200+ meters
• Power Amplifiers: Boost signal strength
• Directional Antennas: Focus attacks on specific targets
• Battery Packs: Enable portable operations

Defense and Mitigation

Understanding these attacks enables better defense strategies:

Detection Indicators

# Signs of WiFi attacks:
# - Duplicate SSIDs with different BSSIDs
# - Sudden client disconnections
# - Unusual deauth frame volumes
# - New APs appearing unexpectedly
# - Clients connecting to unknown networks

Lessons Learned

This project taught me several important concepts about wireless security:

• Hardware Accessibility: Sophisticated attacks are possible with minimal investment
• Social Engineering: Users often reconnect without verifying network authenticity
• Validation Importance: Password validation makes attacks more reliable
• Defense Complexity: Protecting against these attacks requires multiple layers

Future Enhancements

Since completing this initial project, I've identified several areas for improvement:

• Multi-band Support: Adding 5GHz capabilities
• Automated Reporting: Integration with penetration testing frameworks
• Stealth Features: Reduced detectability
• Cloud Integration: Remote monitoring and control

Conclusion

This NodeMCU ESP8266 project demonstrated how accessible hardware can create effective WiFi penetration testing tools. The PhiSiFi framework's password validation feature sets it apart from basic evil twin implementations, providing more realistic assessment of network security.

While this was my first venture into hardware-based wireless testing, it laid the foundation for more advanced projects involving RF security, cellular networks, and IoT device exploitation.