Susan needs an open source tool for remote vulnerability scanning. Which tool would meet her requirements?

OpenVAS is an open-source vulnerability scanning tool that is specifically designed for identifying security issues in systems and networks. This tool provides the ability to assess vulnerabilities remotely, allowing users to scan target systems over the network to discover potential weaknesses that could be exploited by attackers.

One of the key advantages of OpenVAS is that it includes a comprehensive vulnerability database that is regularly updated, making it effective at detecting a wide array of vulnerabilities, particularly those in open-source software. OpenVAS also features a web-based interface, making it user-friendly for security professionals.

Additionally, being an open-source tool means that it is free to use and can be modified or extended by users, which is particularly beneficial for organizations that may want to customize their tools to fit specific needs or to investigate specific vulnerabilities.

Other tools, such as Nessus, Burp Suite, and Qualys, may provide excellent capabilities for vulnerability scanning, but they do not meet the open-source requirement: Nessus is a commercial product after a limited free usage period; Burp Suite is primarily focused on web application security testing; and Qualys is a commercial platform as well. Therefore, OpenVAS is the most suitable choice for Susan's needs for a remote vulnerability scanning tool that is open source.