Tutorial: How to Use GoFire for Creating Cybersecurity Command-Line Applications in Go

In this guide, we will explore how to use GoFire, a powerful CLI generator tool for Go, to create cybersecurity command-line applications. This tutorial is perfect for cybersecurity professionals and hackers looking to build robust CLI tools quickly without writing all the boilerplate code manually and may have less overall programming experience.

What is GoFire?

GoFire is inspired by Python's fire and automatically generates command-line interfaces (CLI) for your Go functions. It handles tasks such as parsing parameters, casting types, setting entry points, and generating help documentation. This tool allows you to focus on your application's logic while it takes care of the plumbing.

Step-by-Step Guide to Using GoFire for Cybersecurity Tools

Let's walk through building various cybersecurity tools using GoFire, with a focus on simplifying the CLI creation process.

1. Setting Up Your Go Environment

Before we dive into building applications, make sure your Go environment is properly set up.

Step 1: Install Go

If you haven’t installed Go yet, follow the instructions here.

Step 2: Install GoFire

Install GoFire using the following command:

go install github.com/1pkg/gofire/cmd/gofire@latest

Step 3: Initialize a New Go Project

Navigate to your desired project folder and initialize a new Go module:

mkdir passwordchecker        

cd passwordchecker        

go mod init passwordchecker        

2. Create a Simple Cybersecurity Command-Line Tool

Let’s start by creating a password strength checker that assesses the strength of a password based on length and the presence of numbers, symbols, and uppercase/lowercase letters.

Step 1: Write the Function

Create a file named main.go and write the core function that checks password strength.

package main

import (
	"fmt"
	"unicode"
)

// CheckPasswordStrength assesses password strength based on certain criteria.
func CheckPasswordStrength(password string) string {
	length := len(password) >= 8
	hasUpper := false
	hasLower := false
	hasNumber := false
	hasSymbol := false

	for _, ch := range password {
		switch {
		case unicode.IsUpper(ch):
			hasUpper = true
		case unicode.IsLower(ch):
			hasLower = true
		case unicode.IsDigit(ch):
			hasNumber = true
		case unicode.IsSymbol(ch) || unicode.IsPunct(ch):
			hasSymbol = true
		}
	}

	var result string
	if length && hasUpper && hasLower && hasNumber && hasSymbol {
		result = "Password strength: Strong"
	} else if length && hasUpper && hasLower && hasNumber {
		result = "Password strength: Moderate"
	} else {
		result = "Password strength: Weak"
	}

	// Print the result directly within the function
	fmt.Println(result)

	return result
}
        

This function checks the complexity of the password by checking for different character classes (upper, lower, numbers, symbols).

Step 2: Generate the CLI with GoFire

Now, we will use GoFire to generate the command-line interface for the CheckPasswordStrength function.

Run the following command from the project root:

gofire --driver=flag --pckg=main . CheckPasswordStrength
        

This will generate a flag.gen.go file, which includes the code to parse command-line arguments and pass them to the function.

Step 3: Run the CLI

Now, you can test the command-line application. Use the following command to run the tool and test the password strength:

go run ./... "P@ssw0rd123"        

Password strength: Strong        

GoFire handles all the CLI details, including parsing arguments, and directly integrates the function you wrote. While the default generates Go code simplistically it also has support for generating command line applications using the very popular Cobra framework in Go which has been used for writing various cybersecurity tools. Essentially if you can learn to write functions in Go you can then generate robust, powerful, and scalable command line tools.

3. Building More Advanced Cybersecurity Tools with GoFire

Let's look at some more complex cybersecurity applications that you can build using GoFire.

Example 1: Log File Analyzer

A log file analyzer can be useful for detecting suspicious activities in server logs. We'll write a function that scans a log file for specific keywords such as "error", "failed", or "unauthorized".

Step 1: Write the Log Analysis Function

Create a new function in main.go that analyzes a log file.

package main

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

// AnalyzeLog scans a log file for suspicious keywords.
func AnalyzeLog(filePath string, keywords []string) {
	file, err := os.Open(filePath)
	if err != nil {
		fmt.Println("Error opening file:", err)
		return
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		for _, keyword := range keywords {
			if strings.Contains(line, keyword) {
				fmt.Println("Suspicious activity detected:", line)
			}
		}
	}

	if err := scanner.Err(); err != nil {
		fmt.Println("Error reading file:", err)
	}
}        

Step 2: Generate the CLI with GoFire

Generate the CLI for the AnalyzeLog function by running:

gofire --driver=flag --pckg=main . AnalyzeLog        

Step 3: Run the CLI

To run this tool, provide a log file path and keywords:

go run ./... /path/to/logfile.log --keywords="error,failed,unauthorized"        

Expected Output:

Suspicious activity detected: Failed login attempt for user admin        

Example 2: Subdomain Enumeration Tool

A subdomain enumeration tool can be useful for identifying potential subdomains for a given domain, which is a common task in penetration testing.

Step 1: Write the Subdomain Finder Function

package main

import (
	"fmt"
	"net"
)

// SubdomainFinder finds subdomains by brute-forcing common subdomains for a domain.
func SubdomainFinder(domain string, subdomains []string) []string {
	var found []string
	for _, subdomain := range subdomains {
		fullDomain := fmt.Sprintf("%s.%s", subdomain, domain)
		_, err := net.LookupIP(fullDomain)
		if err == nil {
			found = append(found, fullDomain)
		}
	}
	return found
}        

Step 2: Generate the CLI with GoFire

Generate the CLI for the SubdomainFinder function:

gofire --driver=flag --pckg=main . SubdomainFinder        

Step 3: Run the CLI

Run the subdomain enumeration tool with the following command:

go run ./... --subdomains="www,api,mail" example.com        

Expected Output:

Found subdomains: [www.example.com api.example.com]        

4. Tips for Using GoFire Effectively

• Use GoFire for Multiple Functions: You can generate CLIs for multiple functions in a single Go project. Just run the gofire command for each function you want to expose as a command-line tool.
• Integration with Build Process: You can integrate GoFire into your build process by adding a //go:generate directive to your Go files. This way, the CLI will automatically regenerate when you run go generate.

//go:generate gofire --driver=flag --pckg=main . CheckPasswordStrength        

Customize CLI Behavior: You can extend GoFire’s functionality by using struct tags to modify how parameters are passed in the CLI. This is useful for grouping flags or setting default values.

Conclusion

In cybersecurity, innovation and efficiency are key to staying ahead of evolving threats. GoFire enables you to quickly build command-line interfaces, allowing you to focus on the core logic of solving real-world security problems. From detecting suspicious log activity to uncovering vulnerable subdomains, GoFire takes care of the boilerplate work, letting you develop powerful tools that make a real impact.

Consider the range of command-line tools you could build with GoFire:

• Port Scanners to identify open and vulnerable ports on a network.
• Hash Crackers to automate brute-force attacks and compare password hashes.
• Vulnerability Scanners that check systems for known weaknesses.
• Active Directory Attack Tools to automate tasks like Kerberoasting, user enumeration, and password spraying.
• Brute-Forcing Tools for attacking login forms or services like SSH, FTP, and RDP.
• Exploit Frameworks to test vulnerabilities across various systems.
• Packet Analyzers to decode and monitor network traffic for anomalies.
• Automation for OSINT (open-source intelligence) gathering to streamline the information-gathering phase of a pentest.

With GoFire, these tools can be developed more quickly than ever, allowing you to iterate rapidly and deploy solutions when you need them. GoFire simplifies the development process, so you can focus on creating innovative solutions, whether you’re automating Active Directory attacks, building brute-forcing tools, or designing a custom exploit framework.

If you're passionate about finding efficient ways to build impactful cybersecurity tools, GoFire is an indispensable part of your toolkit. By automating the tedious aspects of CLI creation, it lets you focus on solving the complex problems that really matter.