Which open-source software is developed from the Nessus codebase for vulnerability scanning?

OpenVAS, or Open Vulnerability Assessment System, is an open-source software that originated from the Nessus codebase. Nessus was initially released as free software, but it later transitioned to a proprietary model, leading to the creation of OpenVAS as a fully open-source alternative focused on vulnerability scanning and assessment.

OpenVAS provides a wide range of tools for network vulnerability scanning and management, leveraging the extensive knowledge and capabilities derived from Nessus. This includes a comprehensive suite of network tests and the ability to detect vulnerabilities based on various factors, including configuration and known vulnerabilities.

The other options listed are related to vulnerability management and scanning but do not share the same direct lineage from Nessus. Qualys is a commercial product known for its cloud-based security and compliance services, while nmap is primarily a network discovery and security auditing tool, not specifically focused on vulnerability management in the same way OpenVAS is. Tenable is the company that develops Nessus, but it is not derived from the Nessus codebase like OpenVAS is. Thus, OpenVAS stands out as the correct choice for this question regarding an open-source software specifically developed from the Nessus codebase.