Gersinia - testing network protocols and generating packets

The Gersinia tool takes advantage of known weaknesses in several network protocols.It helps with trying to abuse the weaknesses to ensure that network protections are implemented where possible.

Screenshots

A modern GUI application for network protocol testing and packet crafting, similar to Yersinia but with updated functionality and a user-friendly interface.

Features

• ARP Spoofing: Perform ARP cache poisoning attacks between targets
• DHCP Starvation: Exhaust DHCP server resources with fake requests
• LLMNR Spoofing: Intercept and respond to LLMNR queries
• Packet Crafting: Create custom network packets with various protocols
• Modern GUI: Built with CustomTkinter for a clean, dark-themed interface
• Real-time Logging: Monitor all activities with timestamped output

Requirements

• Python 3.7+
• Administrator/root privileges (required for packet crafting and network attacks)
• Dependencies listed in requirements.txt

Installation

1. Clone or download the project:

git clone https://github.com/mscbuild/Gersinia
cd Gersinia

2. Install dependencies:

pip install -r requirements.txt

Usage

Running the Application

Windows:

# Run as Administrator
python main.py

Linux/macOS:

# Run as root
sudo python3 main.py

Attack Modules

ARP Spoofing

1. Select a network interface
2. Enter target IP address
3. Enter gateway IP address
4. Click "Start ARP Spoof"
5. Monitor output for attack progress

DHCP Starvation

1. Select a network interface
2. Set the number of DHCP requests (default: 100)
3. Click "Start DHCP Starvation"
4. Watch as DHCP leases are exhausted

LLMNR Spoofing

1. Select a network interface
2. Enter your attacker IP address
3. Click "Start LLMNR Spoof"
4. The tool will respond to LLMNR queries with your IP

Packet Crafting

1. Click the "Packet Crafter" button
2. Add layers to your packet:
   • Ethernet: Configure MAC addresses and EtherType
   • IP: Set source/destination IPs, TTL, protocol
   • TCP: Configure ports, sequence numbers, flags
   • UDP: Set source/destination ports
   • ARP: Configure ARP request/response parameters
   • ICMP: Set type, code, ID, and sequence
3. Click "Build Packet" to construct the packet
4. Preview the packet structure in the preview window
5. Configure send options (count and interval)
6. Click "Send Packet" to transmit

Packet Templates

• Save Template: Save current packet configuration as JSON
• Load Template: Load previously saved packet configurations
• Templates are stored as JSON files for easy sharing and modification

Network Interface Selection

The tool automatically detects available network interfaces:

1. Use the dropdown to select your active network interface
2. Click "Refresh Interfaces" if you change network connections
3. The selected interface is used for all attacks and packet sending

Logging and Output

• All activities are logged in the main output window
• Logs include timestamps and detailed information
• Activities are also saved to network_attack_tool.log
• Use "Clear Output" to reset the display

Security Considerations

IMPORTANT: This tool is designed for:

• Educational purposes and security research
• Network penetration testing with proper authorization
• Understanding network protocol vulnerabilities

Do NOT use for:

• Unauthorized network access
• Malicious activities
• Violating laws or organizational policies

Always ensure you have:

• Explicit permission to test networks
• Proper authorization for penetration testing
• Understanding of legal and ethical implications

Troubleshooting

Common Issues

1. "Administrator privileges required"

   • Windows: Right-click and "Run as administrator"
   • Linux/macOS: Use sudo or run as root

2. "No network interfaces found"

   • Check network adapter is enabled
   • Try refreshing interfaces
   • Ensure you have network connectivity

3. Packet sending fails

   • Verify network interface is correct
   • Check firewall settings
   • Ensure administrator privileges

4. LLMNR spoofing not working

   • LLMNR queries may be disabled on target network
   • Check if port 5355 is blocked
   • Verify target is using Windows name resolution

Development

Project Structure

network_attack_tool/
├── main.py              # Main application and GUI
├── packet_crafter.py    # Packet crafting module
├── requirements.txt     # Python dependencies
└── README.md           # This file

Adding New Attacks

1. Create attack method in main.py
2. Add GUI controls in create_widgets()
3. Implement toggle method for start/stop
4. Add logging for attack status

Protocol Support

The tool supports common network protocols:

• Ethernet II
• IPv4
• TCP/UDP
• ARP
• ICMP
• DHCP
• LLMNR/NetBIOS
• DNS (basic support)

Why it's used

The Gersinia tool helps network administrators and security professionals:

• Test network resilience to Layer 2 attacks.

• Demonstrate vulnerabilities that are often overlooked during security assessments (usually focused on Layer 3/L4).

• Test security settings: Port Security, DHCP Snooping, Dynamic ARP Inspection.

License

This project is for educational and research purposes. Users are responsible for compliance with applicable laws and regulations.

Contributing

Contributions are welcome for:

• New attack modules
• Protocol support
• UI improvements
• Bug fixes
• Documentation updates

Warning

Please ensure all contributions maintain ethical use guidelines.

✅ No vulnerable dependencies detected.