Flagged Port

EasyBash

Overview

In this challenge, you'll scan a range of ports (1337-5337) to locate a hidden flag. One port within this range is serving the flag, which follows the format Flag{...}. Your task is to create an automated Bash script that:

  • Connects to each port in the specified range
  • Checks if the port is open
  • Retrieves the response from open ports
  • Identifies and extracts the flag using pattern matching

Target: Ports 1337-5337
Flag Format: Flag{...}

Lab Details

Prerequisites & Requirements

  • Basic understanding of Bash scripting syntax
  • Familiarity with Linux command-line interface
  • Knowledge of networking fundamentals (TCP/IP, ports)
  • Access to a Linux environment or WSL (Windows Subsystem for Linux)

What will you learn?

  • Building a functional TCP port scanner using pure Bash
  • Leveraging Bash's /dev/tcp pseudo-device for network connections
  • Implementing command-line argument handling in shell scripts
  • Using regular expressions for pattern matching in Bash
  • Managing timeouts and error handling in network operations

Tools

  • Web browser for accessing the challenge
  • Linux-based operating system or terminal environment
  • Text editor (vim, nano, or any preferred editor)
  • Bash shell (version 4.0 or higher recommended)

Job Positions

Ethical Hacker

Tags

Bash ScriptingShellTerminalLinux Commands