OpenVAS vs Nessus: Which is the best choice for you? [2025]

Vulnerability scanning remains one of the most critical pillars of any cybersecurity strategy. As organizations grow their digital infrastructure across cloud workloads, on-prem systems, APIs, and internet-facing applications, the attack surface expands rapidly. Regular vulnerability assessments help security teams identify weaknesses before attackers exploit them, reduce exposure to known CVEs, and meet regulatory and customer security expectations.

Two tools that frequently come up in vulnerability management discussions are OpenVAS and Nessus. Both are widely used, mature scanners, but they are built with different philosophies and target different types of teams. OpenVAS is best known as an open-source solution with deep configurability, while Nessus has become a commercial industry standard focused on scale, performance, and compliance readiness.

This blog breaks down OpenVAS vs Nessus in detail and also introduces Beagle Security as an alternative web and API penetration testing platform for teams that need application-focused, modern security testing beyond traditional infrastructure scanning.

Overview of OpenVAS and Nessus

OpenVAS is an open-source vulnerability scanner maintained by Greenbone as part of the Greenbone Vulnerability Management framework. It relies on a large collection of vulnerability tests, often referred to as Network Vulnerability Tests, which are maintained by the community and Greenbone. OpenVAS is commonly adopted by security professionals, researchers, and smaller teams that want flexibility and full control over their scanning environment.

Nessus, developed by Tenable, is a commercial vulnerability scanner used extensively in enterprise environments. It provides broad vulnerability coverage, frequent plugin updates, and built-in compliance and configuration auditing. Nessus is designed to deliver fast results with minimal setup, making it suitable for organizations that need consistent scanning across large and complex environments.

While both tools aim to identify vulnerabilities, they differ significantly in usability, scalability, maintenance effort, and the type of security problems they are best suited to solve.

OpenVAS vs Nessus at a glance

An alternative web and API penetration testing platform for comparison: Beagle Security

While OpenVAS and Nessus are primarily infrastructure-centric vulnerability scanners, many modern security risks originate at the application and API layer. Authentication flows, business logic flaws, broken authorization, and API misuse are often outside the core focus of traditional network scanners.

Beagle Security is positioned differently. It is an automated web and API penetration testing platform designed to simulate real-world attacks against applications and APIs. Instead of focusing only on missing patches or insecure services, Beagle Security emphasizes how an attacker would actually exploit vulnerabilities in running applications.

This makes Beagle Security a complementary or alternative option for teams that want deeper application-layer coverage alongside or instead of infrastructure scanning.

Why Beagle Security might be a better fit for modern teams

Modern development teams ship code continuously. Applications change weekly or even daily, APIs evolve rapidly, and authentication mechanisms are often complex. In this environment, traditional vulnerability scanners can miss critical issues because they are not designed to understand application workflows or API logic.

Beagle Security is often a better fit for modern teams because it:

• Focuses on web and API attack simulation rather than passive scanning

• Handles authenticated scans and complex login flows

• Produces contextual findings that developers can act on quickly

• Integrates cleanly into CI/CD pipelines for continuous testing

For organizations where application security is a priority, Beagle Security addresses gaps that OpenVAS and Nessus are not primarily designed to cover.

OpenVAS vs Nessus vs Beagle Security: Feature comparison

OpenVAS vulnerability scanning features

OpenVAS provides a wide range of network-level vulnerability checks across operating systems, services, and common software stacks. It supports credentialed and non-credentialed scans, allowing deeper inspection when valid credentials are provided.

Key features include:

• Detection of known CVEs across hosts and services

• Support for custom scan configurations

• Open and transparent vulnerability tests

• Integration with the broader Greenbone ecosystem

However, OpenVAS requires ongoing maintenance. Users are responsible for managing updates, tuning scans, and scaling infrastructure as scan scope increases. Reporting is largely technical, which can make it harder to communicate risk to non-security stakeholders.

Nessus vulnerability scanning features

Nessus is designed for efficiency and breadth. It offers one of the largest vulnerability plugin libraries in the industry, covering operating systems, network devices, databases, cloud services, and misconfigurations.

Key features include:

• Rapid vulnerability detection using updated plugins

• Configuration and compliance audits

• Credentialed scanning for deeper visibility

• High-quality reports with remediation guidance

Nessus excels in environments where speed, scale, and compliance are priorities. Its main limitation is that it focuses more on identifying known weaknesses than simulating real-world exploitation, especially at the application layer.

Beagle Security features

Beagle Security approaches security testing from an attacker’s perspective, focusing on how vulnerabilities can actually be exploited in live applications and APIs.

Key features include:

• Automated web and API penetration testing

• Support for REST and GraphQL APIs

• Intelligent handling of authentication and sessions

• Context-rich reports with proof of exploitability

• Retesting workflows and CI/CD integration

Unlike OpenVAS and Nessus, Beagle Security is purpose-built for application security teams and developers who need fast, actionable feedback on real security risks in production or staging environments.

OpenVAS vs Nessus vs Beagle Security: Pricing comparison

Pricing is often a deciding factor when choosing a vulnerability or penetration testing solution, but it should be evaluated alongside operational effort, scalability, and the type of risks each tool addresses. OpenVAS, Nessus, and Beagle Security follow very different pricing and licensing models, reflecting their intended audiences and use cases.

OpenVAS is attractive from a licensing perspective, but the operational cost of maintaining and scaling it should not be underestimated. Nessus requires a paid license but reduces operational overhead. Beagle Security shifts the cost model toward application-centric risk reduction rather than asset inventory scanning.

OpenVAS pricing

OpenVAS is available as part of the Greenbone Vulnerability Management framework and offers a free, open-source edition that includes community-maintained vulnerability tests. This makes it appealing for organizations with limited budgets, security labs, and learning environments.

However, organizations that need faster vulnerability updates, enterprise support, or better performance often opt for Greenbone’s paid feeds and enterprise subscriptions. While the licensing cost may remain lower than commercial scanners, teams should factor in infrastructure costs, maintenance time, and internal expertise required to operate OpenVAS at scale.

Nessus pricing

Nessus follows a commercial, per-asset licensing model. Pricing typically depends on the number of assets scanned and whether the organization uses Nessus Essentials, Nessus Professional, or enterprise offerings bundled with Tenable’s broader platform.

While Nessus represents a higher upfront cost compared to open-source tools, it reduces operational overhead through easier setup, faster scans, and regularly updated plugins. For many enterprises, the pricing is justified by the time saved and the depth of vulnerability and compliance coverage provided.

Beagle Security pricing

Beagle Security offers tiered plans for web and API penetration testing, with entry level pricing starting around $119 per month and higher tiers for advanced features and enterprise usage. A free trial is available for evaluation.

This model is often more predictable for product teams and SaaS companies, especially those shipping frequently. Instead of paying to scan every host, teams pay for continuous, automated penetration testing that focuses on real attack paths in applications and APIs.

OpenVAS vs Nessus vs Beagle Security: Customer reviews comparison

OpenVAS reviews

G2 rating: 4.2 / 5

OpenVAS is frequently praised for being free, transparent, and flexible. Security professionals appreciate its open-source nature and the ability to customize scans deeply, especially in environments where full control over vulnerability logic is important.

Common feedback themes include:

• Strong technical depth and coverage

• High learning curve for new users

• Manual effort required for setup, tuning, and maintenance

• Limited reporting for non-technical stakeholders

OpenVAS tends to receive positive feedback from experienced security engineers and researchers. However, G2 reviewers often note that it can be challenging for smaller teams without dedicated security resources, particularly when scaling scans or communicating findings to management.

Nessus reviews

G2 rating: 4.5 / 5

Nessus consistently receives strong reviews for reliability, scan coverage, and ease of use. Users frequently highlight how quickly they can deploy Nessus and begin identifying vulnerabilities across large environments with minimal configuration.

Common feedback themes include:

• Fast and scalable scanning performance

• Extensive and frequently updated vulnerability coverage

• Useful compliance and audit-oriented reporting

• Licensing costs increasing as asset counts grow

Nessus is widely trusted in enterprise and regulated environments. G2 reviews often position it as a dependable industry standard, particularly for organizations that prioritize compliance, consistency, and operational efficiency.

Beagle Security reviews

G2 rating: 4.7 / 5

Beagle Security reviews frequently emphasize ease of use, clarity of reports, and developer-friendly findings. Users highlight how the platform helps bridge the gap between security and development teams by focusing on exploitability rather than raw vulnerability volume.

Common feedback themes include:

• Actionable, contextual vulnerability reports

• Strong web and API penetration testing capabilities

• Smooth CI/CD integration for continuous testing

• Reduced noise compared to traditional vulnerability scanners

Beagle Security tends to resonate most with SaaS teams, startups, and product-driven organizations. On G2, it is often praised for helping teams fix real security issues faster, especially in modern application and API-driven environments.

OpenVAS vs Nessus vs Beagle Security: Which is best for you?

The best tool depends on your security goals, team maturity, and the type of assets you are protecting.

Choose OpenVAS if:

• You need a free or open-source solution

• You have strong in-house security expertise

• You are comfortable managing and tuning scanners manually

Choose Nessus if:

• You operate a large or regulated environment

• Compliance and audit readiness are critical

• You want fast results with minimal configuration

Choose Beagle Security if:

• Your primary risk lies in web applications and APIs

• You want automated penetration testing, not just vulnerability listings

• You need developer-friendly reports and continuous testing

Many mature security programs use a combination of these tools to achieve full coverage, using infrastructure scanners for baseline hygiene and application-focused platforms for validating real-world exploitability.

Try Beagle Security for free to see how it compares to Nessus and OpenVAS

Traditional vulnerability scanners such as Nessus and OpenVAS are excellent at identifying missing patches, outdated services, and known CVEs across hosts and networks. However, they are not designed to understand how modern web applications and APIs behave at runtime. Issues like broken authentication flows, insecure authorization checks, API abuse, and business logic flaws often remain invisible to infrastructure-centric scanners.

Beagle Security approaches testing from a different angle. Its automated penetration testing engine simulates real attacker behavior against live web applications and APIs, including authenticated user flows and multi-step interactions. This allows teams to uncover vulnerabilities that only appear when an application is actually running and handling real requests.

For organizations evaluating Nessus or OpenVAS as part of a broader security program, the Beagle Security free trial offers a practical way to see how application-focused testing complements traditional vulnerability scanning. It helps security and development teams understand real-world risk, prioritize fixes that matter, and move beyond vulnerability lists toward actionable security outcomes.

With the free trial, teams can:

• Run automated penetration tests against their own web applications or APIs

• Validate whether vulnerabilities are truly exploitable, not just theoretically present

• Review context-rich reports with clear reproduction steps and remediation guidance

• Test how easily Beagle fits into existing CI/CD pipelines and development workflows

Final thoughts

OpenVAS and Nessus are both capable vulnerability scanners, but they are optimized for different use cases. OpenVAS offers flexibility and transparency for teams with strong technical expertise and limited budgets. Nessus delivers speed, scale, and compliance readiness for enterprise security programs.

However, neither tool fully addresses the growing risks at the application and API layer. For organizations building modern, API-driven products, platforms like Beagle Security provide deeper insight into real-world attack paths and developer-friendly remediation guidance.

In practice, many mature security programs use a combination of tools: infrastructure scanners like OpenVAS or Nessus for baseline hygiene, and application-focused penetration testing platforms like Beagle Security for validating real exploitability where it matters most.

Written by

Jijith Rajan

Cyber Security Engineer

Contributor

Mayookha S Shankar

Product Marketing Specialist