The most secure organizations conduct continuous, ongoing vulnerability assessments for their networks to identify the existing vulnerabilities. This is where vulnerability scanning tools come in handy. The results of such an assessment can help IT teams in understanding the security posture of their network and mitigate risks and enhance defenses against potential threats.

Many vulnerability assessments and penetration testing services involve a use of network vulnerability scanner tool which can be open-source, commercially licensed, or a mixture of both.

Vulnerability scanning tools are extremely useful for allowing organizations to validate any low-hanging fruit vulnerabilities. Lets look at the Top 3 Open-Source tools for Vulnerability Scanning and the Pros and Cons of each:

3. OpenSCAP – Best for Compliance Testing

OpenSCAP is an Linux-based, Open-Source vulnerability scanning tool with strong focus on compliance testing, security tool validation, and policy enforcement. It derives its name from the Security Content Automation Protocol (SCAP), which is maintained by the National Institute of Standards and Technology (NIST).

OpenSCAP is a collection of open-source tools to support web applications, network infrastructure, databases, hosts, but does have an automated vulnerability scanner module. The biggest difference with OpenSCAP is that they test against the SCAP standard, rather than the Common Vulnerabilities and Exposures (CVEs) standard.

Fast discovery of security vulnerabilities with remediation stepsDifficult to learn in comparison to the other tools listed here
Mixture of security vulnerability and compliance network scanningMany other tools besides the vulnerability scanner that may not be needed
Ability to scan docker container imagesDoesn’t follow conventional CVEs standard

2. OpenVAS – Best for General Network Scanning

Open Vulnerability Assessment Scanner or OpenVAS is a full-featured, open-source vulnerability scanner with extensive, large-scale scan coverage. By utilizing the last available open source code for Nessus before they shifted to a proprietary enterprise tool, Greenbone Networks developed OpenVAS. Various plugins for OpenVAS are written using the Nessus Attack Scripting Language (NASL).

OpenVAS maintains high performance all-in-one scanning for network vulnerability tests on endpoints, hosts, networks, and environments. The extensive database of CVEs that OpenVAS searches through allows for thorough insights on any network security issues.

Covers many CVEs with proper remediation stepsRequires prior knowledge on vulnerabity assessment tools and Cybersecurity expertise
Regularly updated and maintained scan database and toolsExcessive use of concurrent scans can crash the tool
Backed by large community for supportLimited capabilities from the Community Edition

1. Nmap – Best for Port Scanning and Validation

Nmap is an lightweight, quick, and effective open-source network scanning tool for port scanning, service fingerprinting, and identifying operation system versions. The Nmap Scripting Engine (NSE) allows Penetration Testers and IT teams to detect security network vulnerabilities and service misconfigurations.

Nmap uses IP packets to scan device ports and determine what is available on the given assets under inspection. Within every asset scanned has hosts, services, versions, and operating systems to be discovered. Nmap also works well when combined with other vulnerability scanning tools to provide validation on identified vulnerabilities.

Fast and reliable port scanner that can determine running services, protocols, applications, and versions.Not beginner friendly – Requires experience in the cybersecurity field and IT knowledge
Proprietary scripts allow for further vulnerability assessment capabilitiesNot entirely all-in-one solution to vulnerability assessments and management
Great synergy with other vulnerability assessment tools to aid in validationLack of formal support

Our Criteria

After researching various Open-Source vulnerability scanning tools, we looked for certain criteria based on the following factors:

While there are many tools out there for vulnerability scanning, there could be some limitations to entering the space with enterprise-level security tools. Our reasoning for creating this list serves to help and assist anyone looking for free, functional, and top-rated tools to help with vulnerability management, assessment, and scans.

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