OpenVAS (Open Vulnerability Assessment System) is a cornerstone tool referenced in the CompTIA PenTest+ curriculum, specifically within the Vulnerability Discovery and Analysis domain. It serves as a comprehensive, open-source vulnerability scanner and manager, often utilized as a zero-cost alterna…OpenVAS (Open Vulnerability Assessment System) is a cornerstone tool referenced in the CompTIA PenTest+ curriculum, specifically within the Vulnerability Discovery and Analysis domain. It serves as a comprehensive, open-source vulnerability scanner and manager, often utilized as a zero-cost alternative to commercial giants like Tenable Nessus or Qualys. Maintained by Greenbone Networks as part of the Greenbone Vulnerability Management (GVM) framework, OpenVAS operates by utilizing a constantly updated feed of Network Vulnerability Tests (NVTs). These NVTs are scripts that check for specific known vulnerabilities, including unpatched software, weak configurations, and protocol flaws.
In the context of a penetration test, OpenVAS is deployed during the active scanning phase to map the attack surface. It supports both unauthenticated scanning—simulating an outside attacker looking for exposed ports and service banners—and authenticated scanning. The latter involves providing credentials to the scanner, allowing it to log into the target system to query local package databases, registry keys, and configuration files, resulting in a much higher degree of accuracy and detail.
OpenVAS automatically scores findings using the Common Vulnerability Scoring System (CVSS), assisting testers in prioritizing risks based on severity. It generates detailed reports in various formats (XML, HTML, PDF) necessary for the final deliverable of an engagement. For PenTest+ candidates, mastering OpenVAS is crucial not just for its scanning capabilities, but for demonstrating the ability to manage false positives, configure scan profiles for specific environments (to avoid denial of service), and interpret technical output to provide actionable remediation advice.
OpenVAS Scanner: Vulnerability Discovery and Analysis
What is OpenVAS? OpenVAS (Open Vulnerability Assessment System), often managed under the Greenbone Vulnerability Management (GVM) framework, is a full-featured, open-source vulnerability scanner. It serves as a critical tool in the Vulnerability Discovery phase of a penetration test. Unlike passive reconnaissance tools, OpenVAS actively probes target systems to identify security loopholes, missing patches, and misconfigurations by comparing the system state against a vast database of known vulnerabilities known as Network Vulnerability Tests (NVTs).
Why is it Important for PenTest+? As an open-source alternative to commercial giants like Tenable Nessus or Qualys, OpenVAS is frequently the tool of choice for budget-conscious organizations and is standard in many Linux distributions (like Kali Linux). For the CompTIA PenTest+ exam, understanding OpenVAS is crucial because it tests your ability to configure scans, interpret XML/HTML reports, and differentiate between scanning modes without relying solely on paid commercial software.
How it Works The OpenVAS architecture functions through several distinct steps: 1. Feed Updates: The scanner downloads the latest NVTs (Network Vulnerability Tests) from the Greenbone Community Feed to ensure it recognizes recent threats. 2. Target Definition: The tester defines the scope (IP addresses, subnets, or hostnames). 3. Configuration: The tester selects a scan profile (e.g., 'Full and fast', 'Discovery'). Crucially, the tester decides between Authenticated (credentialed) and Unauthenticated (non-credentialed) scanning. 4. Scanning: The scanner interacts with the target's ports and services, sending probe packets and analyzing responses against the NVT database. 5. Reporting: It generates reports ranking vulnerabilities by severity (High, Medium, Low, Log) often using CVSS scores.
How to Answer Questions Regarding OpenVAS When facing exam scenarios involving OpenVAS, follow this logic: 1. Identify the Goal: Is the question asking about setup (updating feeds), execution (choosing a scan type), or analysis (reading the report)? 2. Check for Credentials: If the scenario mentions 'missing patches' or 'deep inspection' of registry keys/local packages, the answer usually involves Authenticated/Credentialed Scanning. 3. Analyze Output: If presented with log output, look for CVE IDs and severity ratings. Be prepared to identify False Positives (a vulnerability reported that doesn't exist) vs. False Negatives (a vulnerability exists but was missed).
Exam Tips: Answering Questions on OpenVAS Scanner Tip 1: Credentialed vs. Non-Credentialed Always remember that non-credentialed scans only see what an outsider sees (external services). Credentialed scans log into the machine and see internal configurations. If a question asks why a scanner missed a specific software patch but found open ports, the answer is likely that credentials were not provided.
Tip 2: Greenbone Security Assistant (GSA) OpenVAS is often managed via a web-based GUI called Greenbone Security Assistant. If a question refers to the web interface for managing OpenVAS, GSA is the keyword to look for.
Tip 3: Reducing Noise If a scan takes too long or crashes the target service, look for answers related to tuning the scan intensity or ensuring the Safe Checks option is enabled.
Tip 4: Interpretation You may see a snippet of XML or a screenshot of a report. Focus on the CVSS Score to prioritize remediation. A score of 9.0+ is Critical and should be addressed first.