Tenable Nessus
Overview What it is: Nessus is a proprietary, industry-standard vulnerability scanner developed by Tenable. While OpenVAS is the open-source alternative, Nessus is the commercial heavyweight used by enterprises and government agencies to actively scan networks, servers, and applications for known vulnerabilities, missing patches, and misconfigurations. Target Phase: Enumeration / Vulnerability Assessment Operating System: Cross-Platform (Linux, Windows, macOS)
⚙️ Core Capabilities
- Massive Vulnerability Database: Uses a constantly updated feed of plugins to check for over 120,000 Common Vulnerabilities and Exposures (CVEs).
- Compliance Auditing: Can scan infrastructure against specific regulatory frameworks (like CIS benchmarks, HIPAA, or ISO standards) to ensure configurations meet legal or internal security policies.
- Predictive Prioritization: Uses an algorithm to assign a Vulnerability Priority Rating (VPR), helping teams filter out “noise” and focus on the vulnerabilities most likely to be actively exploited in the wild.
- Credentialed & Unauthenticated Scanning: Capable of scanning from the outside looking in (unauthenticated) or logging directly into the target machine (credentialed) for a deep-dive analysis of local registries, files, and software versions.
💻 Common Commands
Note: Like OpenVAS, Nessus is primarily driven via a Web GUI (running on port 8834 by default), not the command line. However, the service is managed via the CLI.
| Command | Description |
|---|---|
sudo systemctl start nessusd | Starts the Nessus daemon/service on a Linux machine. |
sudo systemctl status nessusd | Checks if the Nessus scanner is currently running. |
https://[Your-IP]:8834 | The default URL to access the Nessus Web UI from your browser. |
⚠️ Notes & Limitations
- Cost: Nessus Professional requires a paid commercial license (typically around $3,500+ per year), though “Nessus Essentials” is free for personal use and can scan up to 16 IP addresses.
- Stealth: Like all vulnerability scanners, Nessus is extremely loud and will immediately trigger Intrusion Detection Systems (IDS).
- The DoD Connection (ACAS): In enterprise defense environments, specifically within the U.S. Department of Defense, Nessus is the core active scanning engine behind the Assured Compliance Assessment Solution (ACAS). If you see ACAS on a network, you are essentially looking at Tenable Nessus and Tenable Security Center doing the heavy lifting.
🔗 Links & Resources
🏷️ Tags
Nessus #Tenable #VulnerabilityScanner #VulnerabilityAssessment #EnterpriseSecurity #ACAS #PenTestPlus