Nessus, developed by Tenable, is a powerful platform designed to scan for security vulnerabilities in various systems—devices, applications, operating systems, and cloud services. This tool started as an open-source project back in 1998, and it became a commercial product in 2005. Nowadays, Nessus offers two enterprise versions: Nessus Professional and Nessus Expert. Both versions allow unlimited vulnerability assessments, but Nessus Expert goes a step further by including features like web application scanning and external attack surface scanning.
So, what can Nessus do? It helps organizations find and fix security weaknesses before attackers can exploit them. It checks for software flaws, missing patches, misconfigurations, and other vulnerabilities across a wide array of systems. Nessus also conducts configuration and compliance audits to help IT teams discover vulnerabilities that increase the risk of cyberattacks. It supports various scoring systems, including the Common Vulnerability Scoring System (CVSS), showcasing how severe different vulnerabilities are.
When Nessus scans an organization’s IT assets, it identifies vulnerabilities and generates detailed reports for remediation. It uses a comprehensive plugin database, updating over 100 plugins every week, ensuring the system stays current with the latest threats. Nessus allows for custom checks based on specific organizational needs, making it flexible and efficient.
A standout feature is the Vulnerability Priority Rating (VPR), which helps teams prioritize vulnerabilities based on severity. It combines Tenable’s collected data with third-party threat intelligence, giving a clearer picture of what needs immediate attention. The Live Results capability means teams don’t always have to run a full scan; they can get vulnerability updates based on previous scans instead.
Generating reports is easy with Nessus, as you can create them in different formats and customize them according to what you need to know—like vulnerability types or affected hosts. The Grouped View feature helps visualize similar issues together, simplifying the assessment process. Additionally, Nessus has a packet capture function to help troubleshoot scanning issues efficiently.
For advanced needs, Nessus Expert includes features like asset discovery, audits against compliance standards, and checks for Active Directory configurations. It’s crucial for scanning internet-facing assets and cloud-based services, along with scanning infrastructure as code (IaC) repositories. This proactive approach ensures vulnerabilities are detected before deployment—helping teams prevent potential issues in production.
The benefits of using Nessus are significant. It allows organizations to assess all types of assets and prevent vulnerabilities from reaching production environments. Frequent scanning can help organizations identify and address misconfigurations and other risks early. Plus, it covers a wide variety of assets, providing coverage for over 77,000 vulnerabilities as of January 2025.
Nessus has a solid reputation for being user-friendly and effective with a low false-positive rate, which is crucial for busy security teams. However, its cost can be a consideration for smaller organizations, especially given the commitment of a one-year license.
When choosing between Nessus Professional and Nessus Expert, it’s essential to know the differences. Nessus Professional, ideal for consultants and security practitioners, covers key features like a vast plugin library and configurable reports. In contrast, Nessus Expert expands on this by providing enhanced capabilities for external and cloud infrastructure assessments, making it suitable for organizations seeking comprehensive vulnerability management.
Both versions use the VPR tool to prioritize vulnerabilities based on threat severity. This sophisticated system integrates machine learning to analyze historical data and generate accurate threat forecasts, allowing security teams to focus on the most pressing vulnerabilities.
Nessus effectively empowers organizations to safeguard their systems and proactively address vulnerabilities. The blend of intuitive use, extensive features, and continuous updates ensures that it remains a vital tool in any cybersecurity strategy.