Which tool is open-source vulnerability scanner used widely?

• A. OpenVAS
• B. Nessus Professional
• C. GFI LanGuard
• D. Nikto

Answer: (A)

Open-source vulnerability scanners are valued for being freely available and community-supported, with broad coverage and regular updates. OpenVAS fits this well and is widely used as the go-to open-source scanner. It’s part of the Greenbone Vulnerability Management project and provides a comprehensive set of checks across many platforms, backed by an active community, which is why it’s a common choice in both labs and production environments.

Nessus Professional is a popular scanner but it’s commercial and not open-source, so it doesn’t fit the “open-source” criterion. GFI LanGuard is also a commercial product with its own licensing. Nikto is open-source and focuses specifically on web server vulnerabilities rather than serving as a broad, general-purpose vulnerability scanner, so it isn’t the best match for “open-source vulnerability scanner used widely.”