Key Points
What is vulnerability scanning? Why do you need it, and how do find the best scanning tool for your needs? Read on to find the best vulnerability scanners for 2025.
TL;DR
- Intruder (free trial available) Best for: Easy but powerful vulnerability scanning, including proactive protection from emerging threats, for non-technical users
- OpenVAS (open-source) Best for: Small businesses with a limited internet footprint
- Probely (free trial available) Best for: DAST web application and API vulnerability scanning
- Acunetix Best for: DAST and IAST web application vulnerability scanning
- Tenable Nessus (free trial available) Best for: Enterprises who have a dedicated security team
- Qualys (free trial available) Best for: Enterprises looking for an extensive feature set
- Rapid7 (free trial available) Best for: IT risk compliance for enterprise organizations
- Nuclei (open-source) Best for: Bug bounty hunters, penetration testers and security researchers
What is vulnerability scanning?
Cyber threats are outpacing most organizations’ ability to prevent them, according to the World Economic Forum. While this might make protecting your data and systems seem daunting, there’s a simple, proactive solution to help you safeguard your network and systems – by using a vulnerability scanner.
Vulnerability scanning tools identify and address cybersecurity weaknesses in your digital infrastructure and systems. When you know where your flaws and weaknesses are, you can fix issues and prevent breaches before they happen. In this article we’ll focus on finding the right solution for your business. If you want a deep dive, check out our Ultimate Guide to Vulnerability Scanning.
How do vulnerability scanners work?
Vulnerability scanners search, monitor and assess your systems for known weaknesses. While these tools were originally designed to scan the IPs or host names which users provide, today’s more advanced vulnerability scanning tools can also discover and inventory network access points and all connected devices. By comparing the scan’s findings to known threats, they give you the insight you need to secure your networks and systems.
Key features of a vulnerability scanner
- Continuous vulnerability detection and monitoring
- Cloud, API and web application scanning
- Risk-based prioritization of vulnerabilities
- Reports that track relevant vulnerability management metrics and show your progress over time
- Downloadable and easy-to-understand reports
- Integration capabilities with your favorite tools
At its core, a vulnerability scanner focuses on finding the flaws that hackers look for to breach your systems. That said, different vulnerability scanning tools perform different tasks. To find the right one for your organization, it’s important to identify your needs and understand the benefits of each before diving in.
Key benefits of using vulnerability scanning tools
- Identify security weaknesses before attackers can exploit them
- Define the level of risk on your network and infrastructure
- Discover and inventory all the systems in your organization
- Keep your business safe over time with continuous monitoring
- Save time and money by preventing costly security breaches
Internal vs. external vulnerability scanning
Vulnerability scans can be external or internal, depending on which part of your digital assets they’re focused on. External scans target externally-facing IP addresses and their open ports to find vulnerabilities and security flaws in your perimeter and cloud systems.
Internal vulnerability scans check inside your firewall to find weaknesses in your internal devices such as outdated or unpatched software. For example, MS Office is a big entry point for attackers and can be vulnerable to phishing attacks, which an external scan wouldn’t find.
Think of it in terms of your home. External vulnerabilities are the open windows, unlocked doors and CCTV blind spots that burglars can exploit to get into your property. Internal vulnerabilities allow the burglar to move from room to room to find and steal your prized possessions.
In practice, this means you might want to scan an IP for external vulnerabilities to see what could be exploited by an attacker, but you also need to see what the attacker could access on the machine locally.
8 tried and tested vulnerability scanning tools
Now you’ve got a better idea of what you want and need to scan, here are our top recommendations for vulnerability scanning tools – open source, free and enterprise-grade – from our own Security team.
Intruder
Intruder combines automated vulnerability scanning with continuous network monitoring and proactive threat response in one platform, making it easy to secure your ever-changing attack surface. Its speed, versatility, and simplicity make remediation, reporting and compliance easy. It checks for 140,000+ vulnerabilities, automatically synchronizes your cloud environments, and sends you alerts when exposed ports and services change. Intruder proactively scans for emerging threats when new vulnerabilities are discovered and provides reports that are easy for non-security experts to understand, prioritize and action.
Top features of Intruder
- Vulnerabilities are prioritized by context for a holistic view of all vulnerabilities, saving time and reducing your attack surface
- Its online vulnerability scanner is easy to set up and use, all you need to know is what to scan - infrastructure, web apps or APIs
- It continuously scans your network, kicking off vulnerability scans when it sees a change, an unintentionally exposed service, or an emerging threat
Who uses it
Because of its ease of use and automated continuous monitoring, Intruder is ideal for tech startups, scale-ups and SaaS businesses with APIs, web apps and assets primarily hosted in the cloud, but without dedicated in-house cyber security or compliance expertise.
Pricing
Intruder offers a 14 day free trial and three plans: Essential, Pro, and Premium, with different licenses available for application and infrastructure scanning. You can pay monthly or annually.
OpenVAS
Open Vulnerability Assessment Scanner (OpenVAS) is a free vulnerability scanning tool. It’s a full-featured tool that provides extensive scanning coverage with the ability to scan for 44,306 vulnerabilities (at the last check). You can find the OpenVAS repository here.
Top features of OpenVas
- Robust and comprehensive vulnerability scanning and management solution, particularly if you’re a small business or start-up with few internet-facing systems
- Can be complex to install and configure, so it’s best suited to more technical experts
- Doesn’t support authenticated web-application scans so you’ll need to go elsewhere if this is important to you
Who uses it
Scanners such as OpenVAS are designed to be used by internal information and security operations center (SOC) teams. OpenVAS provides transparency for senior management to better manage their IT assets and processes.
Pricing
OpenVAS is a free, open-source vulnerability scanning tool.
Probely
One of the lesser-known vulnerability scanning tools on the list, Probely is still a highly capable platform. Its power lies in how the software prioritizes the most important threats. Probely's dynamic application security testing (DAST) scanner scans your web applications and APIs, claiming to only report security vulnerabilities that matter. This reduces the risk of false positives in reports, which are generated with simple instructions on how to fix the most pressing vulnerabilities.
Top features of Probely
- Provides advice on how to fix vulnerabilities as well as a full-featured and well-documented API
- Probely’s spider, based on Headless-Chrome, crawls and indexes interactive JavaScript apps and SPAs
- Automate web application and API testing by integrating it into your CI/CD pipelines with two-way sync with your issue tracking platform
Who uses it
Aimed primarily at developers and DevOps teams who use agile development and want or need to test the apps they’re designing earlier in the development process. Scans can be configured to run frequently and automatically without the need for security professionals.
Pricing
Probely offers a lite option, which requires you to purchase credits beyond the 5 free monthly credits included, as well as Pro and Enterprise plans with the option to pay monthly or annually.
Acunetix
Acunetix uses a blend of dynamic application security testing (DAST) and interactive application security testing (IAST) to detect over 7,000 vulnerabilities, providing extensive reach to protect sensitive data. This includes hard-to-scan places like password-protected areas and multi-level forms.
Top features of Acunetix
- Scheduling makes it simple to schedule one-time or recurring scans in multiple environments
- High level of automation makes prioritizing high-risk areas easier
- Integrates seamlessly with your development tools and DevSecOps processes
Who uses it
Aimed at the enterprise market, Acunetix is used by financial, military, governmental, educational, and technology companies and institutions, with the majority of its customers having 1000-5000 employees and dedicated security teams.
Pricing
Acunetix does not offer a free trial or different pricing plans. You can request a demo or quote on their website.
Tenable Nessus
With the ability to scan 65,000 common vulnerabilities and exposures (CVEs), Nessus is one of the more powerful tools on the market and offers great coverage. As enterprise software, it performed highly in our comprehensive analysis. The platform usually gets new checks out faster than other tools, which is why we chose it as one of the scanners that powers our Pro plan.
Top features of Nessus
- The software is highly configurable and a good fit for more technical users
- Consistently detects the most recent CVEs while still keeping track of legacy vulnerabilities
- Pre-built policies and templates, customizable reporting, group “snooze” functionality, and real-time updates
Who uses it
As one of the most popular commercial scanning engines, Nessus is used by 60% of the Fortune 500 who have dedicated cybersecurity consultants and remediation teams.
Pricing
A Tenable Nessus Professional license starts at $3,590 per year, but this does not include web application scanning, cloud infrastructure scans, or external attack surface scans. Access to support is not included and costs an additional $400 per year. A 7 day free trial is available.
Qualys
Known for its broad scanning capabilities and flexibility, Qualys can scan multiple systems from a single console, including cloud environments and your internal network. You can create custom reports that segment and prioritize data. These reports can be scheduled and generated for more responsive vulnerability management. While the software is advanced, the user experience is quite complex and more suitable for highly technical users.
Top features of Qualys
- Single pane of glass to view all your assets, vulnerabilities, and compliance status
- Constantly updated with latest CVEs so new threats don’t go undetected
- Discovers forgotten devices and helps your internal teams better organize host assets
Who uses it
Qualys is primarily aimed at large organizations, such as enterprises, government agencies, and consultancy groups who have the technical expertise to handle an extensive security product.
Pricing
Qualys does not offer any pricing information on their website; they require that you get in touch for a quote. A free trial is available for the Enterprise TruRisk Platform.
Rapid7
Rapid7 is a live vulnerability and endpoint analytics solution for vulnerability management, designed for companies with large IT networks, especially financial institutions. Its InsightVM solution provides in-depth reports for established security teams and CISOs, but can be overkill for smaller organizations who don’t have the resources and in-house expertise to understand, investigate and fix findings.
Top features of Rapid7
- Collects data from all endpoints, even those that rarely join the corporate network
- Easily create custom cards and dashboards, and query each to track your progress
- Prioritize vulnerabilities on a 1-1000 scale to see those that are actively being exploited in the wild or the likelihood of an attacker exploiting the vulnerability in a real attack
Who uses it
Rapid7 is aimed squarely at medium sized and enterprise organizations who have the expertise required in-house to setup and maintain and more technical tool.
Pricing
Rapid7’s InsightVM is priced based on the number of assets you wish to scan. A free trial is also available.
Nuclei
Nuclei is an open-source vulnerability scanning engine which is fast, extensible, and covers a wide range of weaknesses. It’s popular with bug bounty hunters, pen testers and researchers who want repeatable checks for serious weaknesses. These experts, working with Nuclei’s team at ProjectDiscovery, combine their knowledge and insights about cutting-edge weaknesses to produce checks extremely fast.
Top features of Nuclei
- Specific detection and discovery capabilities which improve attack surface reduction (ASR)
- Checks login panels that shouldn’t be internet exposed
- Provides a wide range of checks for known vulnerabilities in services which are typically internet-exposed
Who uses it?
Nuclei is simple to get up and running without having to read a lot of documentation, but it’s most popular with bug bounty hunters, penetration testers and researchers who want to produce repeatable checks for serious weaknesses.
Pricing
Nuclei is a free, open-source tool.
How to choose the best vulnerability scanner for your needs
- The scanner should be easy to deploy and run. A visual dashboard that clearly conveys the location, nature and severity of a detected threat is a must.
- The scanner must be adequately automated and run continuously to alert you about detected vulnerabilities in real-time.
- The report should list its findings with clear, concise but comprehensive analysis.
- Look for a scanner that scans both your publicly and privately accessible servers, cloud systems, websites and endpoint devices.
Looking for a vulnerability scanner that gives you all this and more? Look no further than Intruder for continuous and comprehensive coverage. Effortless attack surface management that ensures you can identify weaknesses in your system before hackers do. Sign up for a free trial to get started.
