Port Scanning Challenge

A cybersecurity educational challenge that simulates port scanning and connection in a CTF-style environment.

Overview

This challenge teaches participants about port scanning and service enumeration in a controlled environment. Participants must find open ports on a simulated server, connect to them, and collect encoded flag fragments. The challenge is designed to be educational while maintaining the authentic feel of a CTF competition.

Key Features

• Realistic nmap-style scan output
• Service-specific connection responses
• Encoded flag fragments distributed across ports
• Two experimental conditions (control/treatment)
• Progress milestones and CTF-style feedback

Challenge Objective

Participants need to:

1. Scan for open ports on the target system
2. Connect to any 4 of the 8 discovered ports
3. Collect encoded flag fragments
4. Decode the flag (outside the challenge)

Experimental Conditions

The challenge features two conditions that can be toggled with command-line arguments:

1. Control Condition: The eight ports include four lesser-known default ports (e.g., SMTP, DNS, POP3, IMAP) and four non-default (user-defined) ports.

2. Treatment Condition: The eight ports include four well-known default ports (e.g., HTTP, SSH, FTP, HTTPS) and four non-default (user-defined) ports.

All options are presented in random order during the scan.

Flag System

• Each successful port connection reveals part of an encoded flag
• Participants need to connect to any 4 ports to collect all flag fragments
• The encoded flag is split into 4 equal parts
• Milestone messages appear after finding the first and last parts
• A hint about base64 decoding is provided upon completion

Setup and Running

Requirements

• Python 3.6+

Running the Challenge

Basic usage:

python port_scanning_challenge.py

With options:

# Run in control condition 
python port_scanning_challenge.py 


# Run in treatment condition (well-known ports)
python port_scanning_challenge.py --treatment

# Run with debug information
python port_scanning_challenge.py --debug

# Run treatment with debug information
python port_scanning_challenge.py --treatment --debug

• Using Docker
  1. docker build -t port-scanning .
  2. docker run -it --rm port-scanning

Available Commands

During the challenge, participants can use the following commands:

• scan - Scan for open ports
• connect <port> - Connect to a specific port
• status - Display current progress
• help - Display help message
• exit - Exit the challenge

Challenge Flow

1. The participant starts by running a scan to discover open ports
2. For each port they connect to, they receive a fragment of the encoded flag
3. After connecting to 4 ports, they have the full encoded flag
4. They receive a hint about decoding the base64-encoded flag
5. Challenge is completed after collecting all 4 fragments

Error Messages

The challenge provides helpful feedback when:

• Attempting to connect to closed or unscanned ports
• Specifying invalid port numbers
• Using incorrect command syntax

Scoring and Data Collection

At the end of the challenge, a summary is shown with:

• Ports connected
• Total unique ports connected
• Total ports attempted
• Number of flag fragments collected

This information can be used for research or educational assessment.

Developer Notes

You can modify the challenge by:

• Changing the encoded flag in the generate_flag_parts() method
• Adjusting the ports in the control and treatment conditions
• Adding more service-specific responses for different port types