Unlike penetration tests, vulnerability tests do not consist of performing real attacks. However, they’re no less valuable, as they can spot vulnerabilities missed by a penetration test and provide a baseline for comparison. In addition, vulnerability tests allow IT teams to identify weaknesses before they become an actual problem.
The goal is not to be stealthy but to assess risks from the inside, like how hackers would deploy their attack after breaking into a network. That’s why vulnerability tests involve both passive and active scans.
Vulnerability assessment tools usually scan applications for known vulnerabilities. It should be noted that many pentesting solutions also include advanced scanners, so they can be used for vulnerability assessment too. While there are premium products, organizations often leverage the benefits of robust open-source technologies to save money.
Some of the tools we’ll see in this top 10 list are bundled in Kali Linux, a super-charged security distribution that can run both pentests and vulnerability tests. Kali Linux can save a lot of time and remove the hassle of installing each tool separately.
Also see our guides to:
- Breach and attack simulation tools
- Vulnerability scanning tools
- Vulnerability management solutions
- Patch management software
10 Top Open Source Vulnerability Tools
Jump ahead to:
- OWASP Zed Attack Proxy (ZAP)
- Burp Suite Free Edition
There are three categories of vulnerability assessment tools you should consider before making any buying or use decisions: general or multi-purpose tools; specialized scanners; and analysis and fuzz testing tools. We recommend starting with a generic tool and using either a specialized scanner or analysis and fuzz testing tool to complement or fill in a gap for any missing or desired functionalities.
Generic Vulnerability Testing Tools
In this section, you’ll find security suites and frameworks that help run vulnerability tests.
OpenVAS is a multi-purpose scanner, inspired by Nessus, with high capabilities to perform large-scale assessments and network vulnerability tests. The tool collects insights from a massive range of sources, allowing almost blind tests.
- Probably the most comprehensive tool in the list
- Actively maintained by Greenbone
- Covers many CVEs (common vulnerabilities and exposures)
- The scan database is updated regularly
- Can be overwhelming for beginners
- No policy management
OWASP’s Zed Attack Proxy (ZAP), also available on Kali Linux, places itself between the tester’s browser and the web application to intercept requests, hence the term “proxy,” which allows modifying contents or forwarding packets, among other tasks.
- Actively maintained by OWASP teams
- Very comprehensive
- Both graphical and command-line interfaces are available
- Fast learning curve and great documentation
- Convenient for various levels, from beginners to security teams
- Can be harder to install and less friendly to use than premium editions of the Burp Suite
- Requires additional plugins for some features
Burp is one of the most popular security suites available on the market. While the free edition has fewer features than paid plans, it provides a comprehensive series of modules to monitor, intercept, and modify the traffic between the browser and a web application thanks to the Intercepting Proxy feature.
It can also automate web crawling with the application-aware Spider and repeat series of requests with the Repeater tool.
- Maintained by PortSwigger
- Huge community (over 15,000 organizations)
- Can scale vulnerability scanning
- Advanced passive scan features
- Not the most convenient tool to generate reports
- High-value features, such as advanced searches, content discovery, scheduling, and saved sessions, require the professional edition at least, which is relatively expensive.
For more on the Burp Suite, see Getting Started with the Burp Suite: A Pentesting Tutorial
Vega is a comprehensive and automated assessment tool that can detect various flaws such as XSS, SQL injections, dangerous file inclusions, and many more.
- Nice and friendly UI (user interface)
- Includes a website crawler and an automated scanner
- Can do automated, manual, and hybrid security testing
- Still early-stage software
Also read: 10 Top Open Source Penetration Testing Tools
Specialized Vulnerability Scanners
The following tools are less generic and should be used in specific contexts. You can combine them with the previous scanners, though, for more comprehensive testing.
Nikto2 is a web server scanner that can spot dangerous files and programs as well as server misconfigurations hackers want to exploit. Users can also access Nikto on Kali Linux.
- Pretty light but still powerful
- Supports files for input and output
- Can test IDS (intrusion detection systems)
- No interface, only command lines
- Very specific, which can be confusing for beginners
- Lack of support and community
Nexpose by Rapid7, a predecessor to InsightVM, is a popular security solution that offers a real risk score, adaptive security, and policy assessments to help users create in-depth reports on vulnerabilities.
- Always on and based on a constant live list of known exploits
- Can be easily combined with other tools such as Metasploit (pro version)
- Prioritize alerts and attributes scores to exploits
- Policy management and recommendations
- On-premises deployment
- The trial edition has limited features and capabilities (e.g., 32 targets max)
- The free version is now a trial that expires after 1 year
- Requires lots of RAM
- Can generate lots of noise, requiring testers to determine the most important findings
- Seems to have been replaced by InsightVM, which has more capabilities, especially for remediation and reporting
OpenSCAP is an open-source framework for Linux platforms. The Security Content Automation Protocol (SCAP) consists of open standards used to enumerate flaws and misconfigurations. And the scanner provides an extensive range of tools that support scanning on web applications, network infrastructure, databases, and hosts.
- Automates assessments
- Policy management and security benchmark
- Quick identification of security issues and instant corrective operations
- Significantly harder to learn than many other tools
Analysis Tools and Fuzz Testing
This section is for advanced analysis tools and fuzzers you can use to look deeper into your network and find vulnerabilities.
Wireshark is a protocol analyzer used by most professionals and a powerful tool to identify issues in WAN/LAN but also wireless connections. Users can also access Wireshark on Kali Linux.
- Users get the finest details at a microscopic level
- Power users can use advanced filters to inspect networks in depth
- Supports various protocols and formats to export outputs
- Requires advanced skills and knowledge to master protocol analysis and identify suspicious patterns
Aircrack-ng, also available on Kali Linux, is a complete suite of tools to assess Wi-Fi network security. Users can monitor and capture packets or check Wi-Fi cards and capabilities. The tool is often used for pentesting (e.g, packet injections, fake access points, replay attacks) Wi-Fi, but the scanning feature is pretty efficient for vulnerability assessment.
- Light and straightforward
- Users get the finest details at microscopic level
- Allows heavy scripting
- Can be harder to learn and use for beginners
- No graphical interface
VAF (Very Advanced Fuzzer) is a powerful web fuzzer you can install on your distribution, for example, Kali Linux. It’s not pre-bundled but you only have to clone the repository and run the install script git clone https://github.com/d4rckh/vaf.git && cd vaf && sudo -s && ./install.sh.
VAF provides commands to filter files and directories by HTTP status code, detect XSS, fuzz POST data. While users have to provide a URL and a wordlist to make it work, it’s relatively easy to find public lists used in brute-force scanning, which you can scan with your custom list.
- Extra light and pretty straightforward
- Can output results in files, allowing you to schedule scans and save analysis
- Can grep (advanced searches) and detect reflectiveness
- Actively maintained
- Still pretty young
- No GUI (graphical user interface)
- No default wordlist (mandatory parameter)