With an attack happening every 39 seconds, cybersecurity measures are crucial for your survival in the market. Yet, for small teams with limited budgets, free vulnerability scanners offering baseline security have become a lifeline.
However, choosing the right scanner is tricky. While some offer valuable insights, others have limitations that could lull you into a false sense of security. To help you navigate this, let’s explore the benefits of free scanners, our experts’ top 11 picks, and the pitfalls to avoid.
Top 11 Free Online Vulnerability Scanners
- Astra Pentest
- ZAP
- Nmap
- Arachni
- OpenVAS
- Wireshark
- Vega
- Burp Suite Community edition
- Nikto
- W3af
- Kali Linux OS
Why is Astra Vulnerability Scanner the Best Scanner?
- We’re the only company that combines automated & manual pentest to create a one-of-a-kind pentest platform.
- Vetted scans ensure zero false positives.
- Our intelligent vulnerability scanner emulates hacker behavior & evolves with every pentest.
- Astra’s scanner helps you shift left by integrating with your CI/CD.
- Our platform helps you uncover, manage & fix vulnerabilities in one place.
- Trusted by the brands you trust like Agora, Spicejet, Muthoot, Dream11, etc.
Essential Features in a Free Vulnerability Scanner
Scanning Capabilities:
While free scanners may not offer everything, look for options that can scan at least basic website vulnerabilities like SQL injection, cross-site scripting (XSS), and outdated software. Some might even extend to network or API scans.
Target Types:
Identify what you need to scan. Does the free vulnerability scanner of your choice focus solely on websites, or can it handle other targets like web applications or APIs? Make sure it caters to your digital inftrastructre and its scaling requirements.
Vulnerability Database and Accuracy:
A good scanner utilizes a regularly updated database of known vulnerabilities. While no scanning software is perfect, look for one that boasts a high accuracy rate to minimize false positives that waste your time.
Reporting:
Clear and concise reports are crucial. Choose a free vulnerability scanner that details identified vulnerabilities, including their severity level, potential impact, and step-by-step remediation guidance.
Customization:
Some scanners offer limited customization options. Such a free vulnerability scan could involve specifying the depth or excluding certain areas. Any level of customization allows you to tailor the scan to your specific needs.
Ease of Use:
Free scanners should be user-friendly, with a clear interface and straightforward instructions. Since they are primarily built for security experts, they might necessitate fluency in specific technical know-how, although multiple resources are available to get you started.
Top 3 Free Vulnerability Scanners Compared
| Features | Astra Pentest | ZAP | Kali Linux |
|---|---|---|---|
| Scanner Capabilities | Web and mobile application, network and cloud infrastructure scans | Web application scanning | Online and physical systems, applications, and networks |
| Accuracy | Zero false positives (with vetted scans) | False positives possible | False positives possible |
| Scan Behind Login | Yes | No | Yes |
| Integrations | Jenkins, Jira, Slack, GitHub,, GitLab and more. | Jenkins, Jira, and other CI/CD tools | Docker, AWS, Azure, and more. |
| Deployment | Online | Local, Docker, and Cloud | Local, Docker, and Cloud |
| Compliance | GDPR, SOC 2, ISO, HIPAA, and more | OWASP 10 | None |
Top 11 Free Vulnerability Scanners (Expert’s Opinion)
1. Astra Pentest
Key Features:
- Scanner Capabilities: Web and mobile application, network and cloud infrastructure scans
- Accuracy: Zero false positives (with vetted scans)
- Scan Behind Logins: Yes
- Integrations: Jenkins, Jira, Slack, GitHub,, GitLab and more.
- Deployment: Online
The Astra Pentest Platform goes beyond a free website scanner for blacklisting, SEO spam, and general security. As one of the best free vulnerability scanners, their core offering combines an AI-powered automated scanner that runs 9300+ tests with expert manual testing to uncover both CVEs and advanced bugs like payment gateway manipulation.
This comprehensive approach adheres to industry standards (OWASP, SANS 25) and helps maintain compliance throughout the year, all delivered through a user-friendly SaaS interface with a handy Chrome extension for login recording.
Pros:
- Seamlessly integrates with your CI/CD pipeline.
- Continuously scans for vulnerabilities with regularly updated scanner rules.
- Facilitates collaboration with security experts with OSCP, CEH & CVEs to their name.
- Helps you rapidly prioritize vulnerabilities as per criticality.
- Generates custom executive and developer-friendly reports.
- Offers detailed remediation guidance with PoC videos.
Limitations:
- Trial is available at $7 per week.
Astra Pentest is built by the team of experts that helped secure Microsoft, Adobe, Facebook, and Buffer
2. ZAP
Key Features:
- Scanner Capabilities: Web application scanning
- Accuracy: Some false positives are possible
- Scan Behind Logins: No
- Integrations: Jenkins, Jira, and other CI/CD tools
- Deployment: Local, Docker, and Cloud
Built by OWASP, ZAP, or Zed Attack Proxy, it is open-source vulnerability scanning software designed for new application security users and professional penetration testers.
Known to scan OWASP Top 10, it also acts as a proxy server, allowing security analysts to manipulate traffic flowing through the tool and run in daemon mode, controlled via the REST API.
Pros:
- Offers session manipulation, fuzzing, and brute-force attack capabilities.
- Delivers a user-friendly interface, especially for beginners.
Limitations:
- Can generate false positives.
3. NMap
Key Features:
- Scanner Capabilities: Network scanning
- Accuracy: False positives possible
- Scan Behind Logins: No
- Integrations: No
- Deployment: Local/Command Line Tool
Nmap, one of the leading free network vulnerability scanners, helps map networks while facilitating security auditing via service upgrade schedules, host monitoring, and more.
Although designed to scan large cloud networks, it can also map and scan singlet networks. Moreover, its service detection and firewall evasions can be quite helpful during the recon phase of pentesting.
Pros:
- Provides extended functionality thanks to its NSE engine.
Limitations:
- Results might vary over scans.
- Supports a command line interface with no GUI.
4. Arachni
Key Features:
- Scanner Capabilities: Web application scanning
- Accuracy: High accuracy with low false positives
- Scan Behind Logins: Yes
- Integrations: CI/CD tools
- Deployment: Local and Cloud
Arachni, a free web application scanner, can audit complex web applications built with HTML5, JavaScript, AJAX, and DOM manipulation. Written in Ruby, it offers a robust automatic and manual penetration testing framework.
It is known for improving accuracy, identifying false positives, and detecting attack vectors that might evade simpler scanners.
Pros:
- Adapts to changing execution paths to find attack vectors.
- Provides detailed and actionable insights.
Limitations:
- Can be a little resource-extensive for large-scale scanning.
- Offers scanning only for web apps.
5. OpenVAS
Key Features:
- Scanner Capabilities: Network and web application scanning
- Accuracy: High accuracy, but some false positives are possible
- Scan Behind Logins: Yes
- Integrations: Various SIEM tools
- Deployment: Local, Docker, and Cloud
This feature-rich open-source vulnerability scanner tests protocols with and without authentication to identify security weaknesses in your network and web apps. Its frequently updated test cases and powerful programming language help smoothen large-scale assessments.
Part of the Greenbone Vulnerability Management (GVM) framework, it helps automate scanning and delivers professional PDF scan reports.
Pros:
- Offers a plethora of functionalities.
Limitations:
- Interface is a little dated.
6. Wireshark
Key Features:
- Scanner Capabilities: Network
- Accuracy: False positives possible
- Scan Behind Logins: No
- Integrations: Parasoft, ScyllaDB, Solus, and more
- Deployment: Local or Docker
Known for its network analysis, troubleshooting, and security auditing capabilities, Wireshark’s free network vulnerability scanning tool offers extensive functionalities, a user-friendly interface, and significant protocol support.
Moreover, its ability to analyze real-time and historical traffic, reconstruct timelines, pinpoint attack vectors, and comprehend attacker behavior makes it a go-to for security experts and internal teams.
Pros:
- Allows you to filter results as per protocol.
- Helps you demonstrate the encapsulated payloads and headers at the different layer.
Limitations:
- Deployment can be a bit complicated for beginners.
7. Vega
Key Features:
- Scanner Capabilities: Web applications
- Accuracy: False positives possible
- Scan Behind Logins: Yes
- Integrations: None
- Deployment: Manual installation from source code and pre-built packages with JRE
As a popular free vulnerability scanner, Vega offers automated scanning capabilities for swift tests, and acts as an intercepting proxy for more in-depth analysis. Thus, as the name suggests, it intercepts and analyzes web traffic, crawls apps, and identifies vulnerabilities.
Its community-developed plugins offer enhanced functionality, allowing experts to tailor their scans to specific needs.
Pros:
- Checks for SSL/TLS misconfigurations.
- Provides comprehensive scripting support.
Limitations:
- The interface can be a little difficult to understand initially.
8. BurpSuite Community Edition
Key Features:
- Scanner Capabilities: Web application and API scanning
- Accuracy: False positives possible
- Scan Behind Logins: No
- Integrations: None
- Deployment: Local
Equipped with HTTP(s) / WebSockets proxy and history, an essential toolkit (Repeater, Decoder, Sequencer, and Comparer), and a demo version of Burp Intruder, the community edition, as the name suggests, is a free vulnerability scanner with the above capabilities.
The Java-based platform is a go-to tool for developers. However, the advanced understanding of coding makes it inaccessible to non-technical personnel.
Pros:
- Allows users to intercept and modify traffic.
Limitations:
- Not reliable for scanning logically dependent APIs.
9. Nikto
Key Features:
- Scanner Capabilities: Web application and server scanning
- Accuracy: Moderate, false positives possible
- Scan Behind Logins: No
- Integrations: No
- Deployment: Local
Nikto is a free vulnerability scanner for web apps and servers. It is known for scanning against 6,700+ known vulnerabilities and version checking for 1,250+ web servers.
With single and multiple port scanning, it helps security experts pinpoint open directories, insecure file permissions, and weak HTTP headers while fostering an education environment for cybersecurity.
Pros:
- Offers customization plugin support.
- Can scan multiple hosts in the same session
Limitations:
- Fails to analyze vulnerability exploits and their impact in detail.
- Lacks advanced reporting capabilities.
10. W3af
Key Features:
- Scanner Capabilities: Web applications
- Accuracy: False positives possible
- Scan Behind Logins: Yes
- Integrations: None
- Deployment: Local and Docker
Web Application Attack and Audit Framework, better known as W3af, is a free vulnerability scanner designed to pinpoint and exploit web application vulnerabilities. Unlike most open-source tools, it goes beyond the laundry list of tools to analyze their impact and report in order of severity.
It offers over 200 plugins ranging from discovery, attack, and output plugins to automate repetitive tasks and deliver customizable yet comprehensive security abilities.
Pros:
- Supports both Limitationsole and GUI interfaces.
- Suitable for pre-deployment testing.
Limitations:
- Complex apps can lead to higher false positives.
- GUI navigation may require a learning curve.
It is one small security loophole v/s your entire website or web application.
Get your web app audited with
Astra’s Continuous Pentest Solution.
11. Kali Linux OS
Key Features:
- Scanner Capabilities: Online and physical systems, applications, and networks
- Accuracy: False positives possible
- Scan Behind Logins: Yes
- Integrations: Docker, AWS, Azure, and more.
- Deployment: Local, Docker, and Cloud
With over 600 pre-loaded free vulnerability scanning tools to handle every penetration testing stage, Kali Linux OS facilitates everything from initial recon to post-exploitation analysis.
Its customizable and well-supported learning resources, with regular patches, make it an essential tool for experts and enthusiasts alike.
Pros:
- Delivers speedy execution of tasks and automation capabilities.
Limitations:
- Necessitates fluency in Linux commands and comes with a bit of a learning curve.
Common Pitfalls of Free Vulnerability Scanners
1. Limited Scope and Accuracy
Free scanners often focus on identifying well-known vulnerabilities using predefined checks, potentially missing zero-day exploits, or those requiring manual verification. This can lead to a false sense of security and expose unseen vulnerabilities.
2. False Positives
Due to simpler algorithms, free vulnerability scanning tools may struggle to differentiate between true vulnerabilities and harmless code. This barrage of false positives wastes valuable time for security experts who must manually investigate each alert.
3. Limited Functionality
Such scanners often lack advanced features like penetration testing capabilities, deeper exploit analysis, or vulnerability prioritization. These features are crucial for a comprehensive security assessment, leaving security experts potentially to cobble solutions from multiple tools.
4. Security Concerns
They may collect scan data or require user access to your systems. Security experts should be wary of scanners with vague data privacy policies or those hosted on insecure platforms, as this could introduce unintended vulnerabilities.
Final Thoughts
While free vulnerability scanners can’t guarantee ironclad security, they offer a valuable first line of defense, providing a baseline security check for organizations with limited budgets or security teams.
Consider factors like scanning capabilities (Astra Pentest offers a wide range covering web applications, mobile apps, networks, and cloud infrastructure), target types (need to scan web apps or APIs? ZAP or Burp Suite Community Edition excel there), and accuracy (minimize wasted time investigating false positives with Astra Pentest’s vetted scans).
Remember, no single free scanner is perfect, so weigh your needs and explore these options to find the best fit for your situation.
FAQs
Is vulnerability scanner illegal?
Paid or free vulnerability scanners themselves aren’t illegal, but using them on a system or a target without permission has legal repercussions. Always get the owner’s go-ahead before scanning to avoid any legal trouble.
What are the three types of vulnerability scanners?
There are three main types of vulnerability scanners: network scanners identify weaknesses across your connected devices, host-based scanners delve into individual systems for vulnerabilities and web application scanners specifically target your website’s code for security holes.
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