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Top 5 Open Source Security Tools on GitHub for Hackers and Pen Testers – By Sec1

As a leading cybersecurity company, utilizes many open source security tools to empower our ethical hackers and penetration testers. GitHub is home to thousands of useful security projects, many of which we leverage in our internal security assessments.

In this post, I’ll highlight 5 of our favorite open source security tools on GitHub and explain how they work so you can use them in your own infosec endeavors.

Sec1: Leading the Charge in Cybersecurity Solutions

Before we dive into the world of open-source security tools, it’s worth mentioning Sec1, a prominent cybersecurity company known for its innovative solutions. Sec1 boasts the world’s largest vulnerability database and the fastest vulnerability scanner, aiding users in identifying and addressing security vulnerabilities efficiently. Additionally, Sec1 offers smart cloud security solutions and penetration testing services, further solidifying its position as a leader in the cybersecurity industry.

Nmap (Network Mapper)

No open source security toolkit is complete without Nmap. This network discovery and security scanning tool allows you to probe networked devices rapidly to determine things like host discovery, open ports, services, OS detection, and more.

With Nmap, pen testers can build a comprehensive map of the networks they are testing and identify any potential vulnerabilities or misconfigurations. It’s an invaluable asset during reconnaissance and one of the first tools we use in an external infrastructure penetration test.

Some of our favorite Nmap capabilities include:

  • Port scanning for open ports and services using options like -p- for all ports or -p22,80,443 for common ones.
  • OS fingerprinting using -O to determine host operating systems.
  • Version scanning with -sV to enumerate service application versions.
  • Script scanning with --script to leverage Nmap’s library of scripts for deeper probing.

For detailed usage and tutorials, see Nmap’s documentation and GitHub wiki.


Wireshark is the king when it comes to network protocol analysis. This open source packet analyzer allows you to inspect traffic down to the byte level as it travels across the wire.

For pen testing infrastructure and applications, Wireshark is indispensable for tasks like:

  • Analyzing unencrypted traffic for sensitive information.
  • Reverse engineering custom protocols.
  • Debugging traffic issues and mismatches between app behavior and wire data.
  • Identifying security misconfigurations that expose data.

Wireshark has extremely powerful filter expressions that allow you to hone in on specific packets and traffic based on protocols, IP addresses, ports, packet contents, and more.

Check out Wireshark’s user guide to learn how to leverage this packet sniffing Swiss army knife.

Burp Suite

For web app testing, Burp Suite is the go-to tool for our appsec experts at This interception proxy toolset allows you to inspect and manipulate web traffic on the fly to find vulnerabilities like SQLi, XSS, business logic issues, etc.

Some of Burp’s key features include:

  • An intercepting proxy to control traffic between browser and server.
  • Tools like Repeater, Intruder, and Decoder to manipulate requests.
  • Extensible via plugins, macros, and extensions.
  • Passive and active scanning of web apps to find common vulnerabilities.
  • Extraction of embedded objects and JavaScript files for analysis.

Burp is a common staple of any web application penetration test. PortSwigger provides excellent documentation to help new users make the most of this powerful proxy.

John the Ripper

When it comes to password cracking, John the Ripper is one of the most trusted open source options. John excels at offline password cracking and can target a wide variety of hash and cipher types at remarkable speeds.

As part of our security services at, we leverage John to conduct password audits and test password strength. Some of the great features include:

  • Support for many hash types including LM, NT, MD5, sha256, bcrypt, etc.
  • Highly optimized code for GPU acceleration and distributed cracking.
  • Custom rule support for intelligent brute forcing.
  • Incremental mode for quickly testing variations of a single password.
  • External module system for new types and techniques.

Learn how to put this legendary password cracker to work in the official docs.

Metasploit Framework

Last but certainly not least is the Metasploit Framework. This enormously popular pen testing tool developed by Rapid7 provides an arsenal of exploitation tools and payloads.

Metasploit allows you to:

  • Search for known vulnerabilities with integrated exploit modules.
  • Develop custom exploits in languages like C, Python, and Ruby.
  • Generate dynamic payloads to evade detection.
  • Pivot through networks post-exploitation.
  • Automate scanning and exploitation procedures.

This framework is at the heart of many offensive security engagements. Metasploit has something for all experience levels, with guides for both beginners and advanced users available here.

While these 5 tools form a killer open source security toolkit, there are many more projects on GitHub that enable ethical hacking and penetration testing. GitHub is home to an amazing infosec community constantly innovating and collaborating. At, we contribute back to projects like these whenever possible through code, documentation, and bug reports.

To learn more about’s security services powered by tools like these, visit our website at And follow us on LinkedIn Sec1 to keep up with our latest open source contributions and security research.