Free & Open Source Cybersecurity Tools (2026)
Antivirus, vulnerability scanners, OSINT, encryption, SIEM, and more. Curated and reviewed by category.
Browse 0 cybersecurity solutions, with 0 security professionals searching monthly
Quick Reference
- What is the best free antivirus in 2026?
- For Windows, Microsoft Defender is the default and consistently scores in the top tier of independent tests. Bitdefender Free Antivirus is the cleanest third-party alternative. ClamAV remains the standard for Linux servers and email gateways.
- What is the difference between free and open source security tools?
- Free tools cost nothing to use but may be closed source (Microsoft Defender, vendor free tiers). Open source tools publish their source code under licenses like Apache, MIT, or GPL — you can audit, modify, and self-host. Open source needs more operational effort but is more transparent and customizable.
- Which free SIEM is production-ready?
- Wazuh is the most capable free open source SIEM, with HIDS, file integrity monitoring, vulnerability detection, and compliance dashboards built in. ELK Stack with security tuning and OSSEC are mature alternatives.
- Are open source security tools as good as commercial ones?
- For specific use cases, yes. Wazuh rivals Splunk for detection, OpenVAS rivals Nessus for scanning, OWASP ZAP rivals Burp Suite Pro for testing, and Bitwarden matches 1Password for most teams. The trade-off is operational overhead and the absence of vendor support SLAs.
Acronym Glossary
- SIEM
- Security Information and Event Management — centralized log collection, correlation, and alerting platform.
- HIDS
- Host Intrusion Detection System — agent that monitors a single endpoint for suspicious activity, file changes, and policy violations.
- SAST
- Static Application Security Testing — scans source code for vulnerabilities without executing it.
FEATURED
OPEN SOURCE
Automate Google Hacking Database scraping and searching with Pagodo, a tool for finding vulnerabilities and sensitive information.
A tool to remove malicious artifacts from Microsoft Office documents, preventing malware infections and data breaches.
A reconnaissance tool that retrieves information from Office 365 and Azure Active Directory using a valid credential.
A toolkit to attack Office365, including tools for password spraying, password cracking, token manipulation, and exploiting vulnerabilities in Office365 APIs and services.
A lightweight Command and Control (C2) implant written in Nim that provides remote access capabilities for penetration testing and red team operations.
A collaborative, multi-platform, red teaming framework for simulating attacks and testing defenses.
A macOS Initial Access Payload Generator for penetration testing and red teaming exercises.
MSBuildAPICaller is an offensive security tool that enables interaction with the MSBuild API to execute arbitrary scripts for red teaming and penetration testing purposes.
Mortar is an evasion technique to defeat and divert detection and prevention of security products, including AV, EDR, and XDR solutions.
Modlishka is a reverse proxy tool for intercepting and manipulating HTTP traffic, ideal for penetration testers, security researchers, and developers to analyze and test web applications.
A cross-platform HTTP/2 Command & Control framework written in Golang for post-exploitation activities and remote system management.
Macro_Pack automates the generation and obfuscation of Office documents and scripts for penetration testing and security assessments.
A LinkedIn reconnaissance tool for gathering information about companies and individuals on the platform.
An OSINT tool that generates username lists for companies on LinkedIn for social engineering attacks or security testing purposes.
A COM Command & Control framework that uses JScript to provide fileless remote access capabilities on Windows systems through a modular plugin architecture.
Ivy is a payload creation framework for executing arbitrary VBA source code directly in memory, utilizing programmatical access to load, decrypt, and execute shellcode.
InvisibilityCloak is a proof-of-concept C# code obfuscation toolkit designed for red teaming and penetration testing to conceal post-exploitation tools from detection.
A tool for working with Direct System Calls in Cobalt Strike's Beacon Object Files (BOF) for offensive security purposes.
A template-driven framework for creating custom evasion techniques to test Anti-Virus and EDR detection capabilities.
An open-source phishing toolkit for businesses and penetration testers.
A tool that generates .NET serialized gadgets for triggering assembly load and execution through BinaryFormatter deserialization in JavaScript, VBScript, and VBA scripts.
A standalone man-in-the-middle attack framework used for phishing login credentials and bypassing 2-factor authentication.
EvilClippy is a cross-platform tool that creates malicious MS Office documents with hidden VBA macros and evasion techniques for penetration testing and red team operations.
An open-source tool that automates the detection and analysis of DLL hijacking vulnerabilities in Windows applications, providing detailed reports and remediation guidance.
