Top 10 Free Cyber Security Tools for SMBs

Introduction

UK small businesses can build meaningful cyber defences without paying for enterprise software. Free and open-source tools — combined with the NCSC’s free services — can cover the four fundamentals: password security, endpoint protection, vulnerability scanning, and phishing awareness. This guide lists 10 tools trusted by UK security professionals in 2026, why each matters, and how to combine them for Cyber Essentials readiness. 

Are they really free?

You get what you pay for, right? Possibly, but in many cases, no!

However, when considering whether to pursue the use of a free cyber security tool, it’s essential to understand the different types available and why they are being offered for free. Each type not surprisingly has its own benefits and risks, which make them suitable for various scenarios, but not for others.

In general there are three main types of free tool: open source, freemium and Government backed. Let’s take a look at each.

Open Source Free Cyber Security Tools

Open source cyber security tools are typically developed and maintained by a community of developers and are available for free. The source code for these tools is open for anyone to use, inspect, modify and enhance (or corrupt!).

People build these tools for various reasons, including the belief in open collaboration and the shared goal of improving cyber security. Many open source developers are motivated by the desire to improve security for everyone, not just those who can afford expensive paid solutions.

The collaborative nature of open source projects allows for continuous improvement and rapid response to emerging threats, as multiple contributors can identify and address issues more quickly than a single entity. They also allow for organisations to modify and adapt the tools to meet their specific needs.

On the flip side, using open source tools to provide essential cyber security controls does come with some notable risks.

Firstly, open source tools can be quite complex to setup and use. You’ll need to leverage a skilled member of your existing IT team, or ask for help from an external cyber security team. But it can be well-worth the effort.

More importantly, any use of open source tools needs to consider the risk of vulnerabilities being introduced into the software. Given that anyone can update open source software, it is possible for malicious code to be introduced, which then needs to be detected and removed by the rest of the community. For example, the OpenSSL Heartbleed vulnerability in 2014 was a result of a flaw in an open source encryption library, which went unnoticed for several years before being detected.

Freemium Free Cyber Security Tools

There are variety of premium cyber security tools that offer free (freemium) versions of the same platform, which can be an excellent solution for start-ups and SMBs operating on tight budgets. These free versions are typically designed to provide essential features and functionality to smaller teams or individual users, serving as a gateway to the more comprehensive paid versions.

Freemium cyber security tools, like their paid-version older siblings, are generally designed to be user-friendly, easy to deploy and accessible even to those without extensive technical expertise. This ease of use allows small businesses and start-ups to implement essential security measures quickly and efficiently. Additionally, Freemium tools typically come with access to professional support and resources, providing valuable assistance and guidance that can help users maximise the tool’s effectiveness.

Despite their advantages, freemium cyber security tools also come with some drawbacks. One of the main limitations is the restricted functionality of the free version, which might not cover all the security needs of a business and can quickly become a frustration. While the basic version can be sufficient for initial use, advanced features necessary for comprehensive protection often require a paid subscription.

Despite these limitations, the free versions of these tools can provide substantial value, especially for organisations just starting out or those with limited budgets.

Government Backed Free Cyber Security Tools

These tools are developed and provided by government agencies (such as the UK’s National Cyber Security Centre or the US Cybersecurity and Infrastructure Security Agency) with the aim of enhancing the cyber security posture of businesses and individuals.

Governments have a vested interest in the overall cyber security of their nation’s businesses and infrastructure. By providing free high-quality cyber security resources, they aim to protect sensitive information, prevent cyber-attacks, and maintain the economic stability of SMBs.

Best Free Cyber Security Tools for SMBs

Tool	Category	Source Type	Best For
KeePassXC	Password manager	Open source	Password hygiene
Bitwarden (free tier)	Password manager	Freemium	Cloud password sync
Microsoft Defender	Endpoint antivirus	Built-in	Windows SMBs
OpenVAS / Greenbone CE	Vulnerability scanning	Open source	External/internal scans
Have I Been Pwned	Credential breach check	Free service	Monitoring
GoPhish	Phishing simulation	Open source	Security awareness
NCSC Exercise in a Box	Tabletop exercises	NCSC (free)	Incident readiness
NCSC Early Warning	Threat intel	NCSC (free)	Attack surface monitoring
OpenSCAP	Config compliance	Open source	Hardening baselines
Nmap	Network discovery	Open source	Asset inventory

1. KeePassXC (Open Source)

What is it: A Password Manager

Website: https://keepassxc.org/

Overview

KeePassXC is a free, open-source password manager that helps you store and manage your passwords securely. It is a modern, community-driven fork of KeePass, designed to be more user-friendly and fully cross-platform.

It allows you to organise your passwords in an encrypted database, which is protected using a master password and/or key file. The database uses strong encryption algorithms such as AES-256 and ChaCha20 to keep your data secure.

Unlike the original KeePass, KeePassXC includes many features built-in (rather than relying on plugins), making it easier to use out of the box.

Key Features

• Strong encryption (AES-256, ChaCha20)
• Native apps for Windows, macOS, and Linux
• Built-in browser integration (Chrome, Firefox, Edge, etc.)
• Generates secure, complex passwords
• Built-in TOTP (two-factor authentication code generation)
• Supports key files and hardware keys (e.g. YubiKey)
• No plugin dependency (core features included by default)

Usage and Installation

KeePassXC is available for Windows, macOS, and Linux with native support.

Installation is straightforward:

1. Download the installer from the official KeePassXC website
2. Run the installer and follow the setup instructions
3. Create a new encrypted database
4. Add and organise your passwords securely

You can also enable browser integration for easier autofill functionality.

Pros

• Free and open-source
• Strong, modern encryption methods
• Native cross-platform support (no unofficial ports needed)
• More user-friendly interface than KeePass
• Built-in features (no need for plugins)
• Active development and regular updates

Cons

• No plugin ecosystem (less extensible than KeePass)
• No native cloud synchronisation (requires third-party services like Dropbox, Google Drive, etc.)
• No official mobile app (but compatible with mobile apps that support .kdbx files)

Ideal For

KeePassXC is ideal for individuals and SMBs looking for a secure, easy-to-use, open-source password manager without the complexity of plugins. It’s particularly well suited for users on macOS and Linux, or anyone who prefers a more modern interface with built-in functionality while maintaining strong security.

2. BitWarden (Free Tier)

What is it: A Password Manager

Website: https://bitwarden.com/

Overview

Bitwarden is a free, open-source password manager that allows you to securely store and manage your passwords and sensitive information. It uses a cloud-based, end-to-end encrypted vault that syncs across devices, making it accessible from anywhere.

The free tier is one of the most feature-rich available, offering core functionality such as password storage, syncing, and sharing without requiring a paid subscription. Bitwarden uses a zero-knowledge security model, meaning only you can access your data. 

Key Features

• Strong encryption (AES-256, end-to-end encryption)  
• Unlimited password storage and vault items  
• Access across multiple devices (desktop, mobile, browser)  
• Built-in password generator
• Secure password sharing (one-to-one)  
• Two-factor authentication (basic methods)  
• Cloud sync included (no setup required)
• Open-source and regularly audited

Usage and Installation

Bitwarden is available across multiple platforms including:

• Windows, macOS, Linux (desktop apps)
• iOS and Android (mobile apps)
• Browser extensions (Chrome, Firefox, Edge, etc.)

Installation is straightforward:

1. Create a free account on the Bitwarden website
2. Install the app or browser extension
3. Log in and start adding passwords to your vault

Your data will automatically sync across devices via Bitwarden’s cloud service.

Pros

• Free and open-source
• Very generous free tier (more features than most competitors)  
• Syncs across devices without extra setup
• Available on all major platforms
• Simple sharing and collaboration features
• Option to self-host for advanced users

Cons

• Some advanced features (e.g. advanced 2FA, reports) require Premium
• Interface is functional but less polished than some paid tools
• Relies on cloud storage (unless self-hosted)
• Free support is limited to community/email

Ideal For

Bitwarden’s free tier is ideal for individuals and SMBs who want a secure, low-cost password manager with strong core features and automatic syncing across devices. It’s particularly well suited for users who want an easy setup without managing files manually, while still benefiting from open-source transparency and strong security.

3. Microsoft Defender

What is it: Antivirus & Security Suite

Website: https://www.microsoft.com/en-gb/windows/comprehensive-security

Overview

Microsoft Defender is a built-in security solution included with Windows that provides antivirus, malware protection, and general device security. It is part of the broader Microsoft security ecosystem and works automatically in the background to protect your system.

It uses real-time protection, cloud-based intelligence, and machine learning to detect and block threats such as viruses, ransomware, and phishing attacks.  

Unlike third-party antivirus tools, Microsoft Defender comes pre-installed and requires minimal setup, making it a convenient default security option for individuals and organisations.

Key Features

• Real-time protection against malware and viruses  
• Strong threat detection using cloud intelligence and machine learning  
• Built-in with Windows (no installation required)
• Ransomware protection (e.g. controlled folder access)  
• Automatic updates for virus definitions
• Integration with Microsoft Edge and system security features  
• Tamper protection to prevent unauthorised changes  

Usage and Installation

Microsoft Defender is included by default on Windows devices.

Usage is straightforward:

1. Open Windows Security from the Start menu
2. Navigate to Virus & threat protection
3. Run scans or review protection status

No separate installation is required, and updates are handled automatically through Windows Update.

Pros

• Free and built into Windows
• No setup required
• Real-time protection and automatic updates
• Lightweight with minimal performance impact
• Integrates well with the Windows ecosystem

Cons

• Limited features compared to premium security suites
• Less customisation and control for advanced users
• Primarily focused on Windows (limited cross-platform support)
• Enterprise features require Microsoft 365 / Defender for Endpoint

Ideal For

Microsoft Defender is ideal for individuals and SMBs looking for a simple, no-cost, built-in security solution. It is particularly well suited for users who want basic protection without installing additional software, and for organisations already using Microsoft environments.

4. OpenVAS (Open Source)

What is it: A vulnerability scanner

Website: OpenVAS

Overview

OpenVAS (Open Vulnerability Assessment System) is a full-featured vulnerability scanner capable of identifying security issues in systems and networks. It is part of the Greenbone Vulnerability Management (GVM) solution and provides comprehensive scanning capabilities along with detailed reporting and remediation suggestions.

Key Features

• Extensive vulnerability scanning
• Regular updates with new vulnerability tests
• Detailed reports with remediation advice
• Supports large-scale network scanning
• Open-source and free to use

Usage and Installation

OpenVAS can be installed on various Linux distributions. Installation involves adding the Greenbone repository, installing the necessary packages, and configuring the scanner. Detailed installation instructions are available on the Greenbone website. Once installed, users can configure and run scans via the web-based interface.

Pros

• Comprehensive vulnerability detection
• Regularly updated tests
• Detailed and actionable reports
• Scalable for different network sizes
• Open-source and community-supported

Cons

• Installation and configuration can be complex
• Requires regular updates for optimal performance
• High resource usage during extensive scans

Ideal For

OpenVAS is ideal for SMBs with internal IT staff capable of managing and interpreting vulnerability scans. It suits businesses looking for a robust, scalable solution to identify and mitigate security risks. OpenVAS is particularly beneficial for those who prefer open-source tools and need a comprehensive vulnerability management system.

5. Have I Been Pwned? (Freemium)

What is it: A password breach checker

Website: Have I Been Pwned?

Overview

Have I Been Pwned? is a free online service that allows users to check if their personal information has been compromised in a data breach. By entering an email address, users can see if their credentials have been exposed and receive details about the breaches involved. The service also offers notifications for future breaches involving the user’s email address.

Key Features

• Search for compromised email addresses
• Details of known data breaches
• Notification service for new breaches
• Integration with popular password managers
• API for developers

Usage and Installation

Using Have I Been Pwned? is simple and does not require any installation. Visit the website, enter your email address in the search bar, and click “pwned?” to check if your email has been compromised. To receive notifications about future breaches, you can subscribe by providing your email address.

Pros

• Provides detailed breach information
• Easy-to-use interface
• Notification service for new breaches
• Trusted and widely used

Cons

• Freemium version is limited to checking domains with up to 10 email addresses
• Relies on publicly available breach data
• No remediation advice provided

Ideal For

Have I Been Pwned? is ideal for individuals and SMBs who want a quick and easy way to check if their email addresses have been compromised in data breaches. It is particularly useful for monitoring the exposure of sensitive information and staying informed about new breaches. This service is suitable for those who want to take proactive steps in safeguarding their online accounts without needing technical expertise.

6. GoPhish (Open Source)

What is it: A phishing training tool

Website: GoPhish

Overview

GoPhish is an open-source phishing simulation tool designed to help organisations conduct and manage phishing campaigns. It allows users to create and launch targeted phishing emails to test the security awareness of employees and provides detailed reports on campaign performance and user responses.

Key Features

• Easy-to-use web interface
• Customisable email templates and landing pages
• Real-time reporting and analytics
• User and group management
• API for integration with other systems

Usage and Installation

GoPhish can be installed on various operating systems, including Windows, macOS, and Linux. To get started, download the appropriate version from the GoPhish website, extract the files, and run the executable. Detailed installation and setup instructions are available in the GoPhish documentation.

Pros

• Open-source and free to use
• Highly customisable phishing simulations
• Real-time tracking and reporting
• Supports multiple operating systems
• Active community and documentation

Cons

• Requires technical knowledge for setup and management
• No built-in training content for users
• Potential for misuse if not ethically managed

Ideal For

GoPhish is ideal for SMBs and larger organisations looking to improve their employees’ security awareness through phishing simulations. It is particularly beneficial for IT and security teams who have the technical skills to set up and manage the tool. GoPhish is suitable for organisations that need a flexible and cost-effective solution to conduct regular phishing awareness training and measure its effectiveness.

7. NCSC Exercise in a Box

What is it: Cyber Security Awareness & Training Tool

Website: https://www.ncsc.gov.uk/section/exercise-in-a-box/overview

Overview

Exercise in a Box is a free, online cyber security training tool developed by the UK’s National Cyber Security Centre (NCSC). It is designed to help organisations test and improve their response to common cyber security incidents in a safe, simulated environment.

The platform provides guided, scenario-based exercises (such as phishing attacks or ransomware incidents) that can be run internally without requiring technical expertise. These exercises help teams understand risks, improve awareness, and practise incident response.

Key Features

• Free, NCSC-developed cyber security training resource
• Scenario-based exercises (e.g. phishing, ransomware, data breaches)
• Designed for non-technical users and small teams
• Facilitator-led sessions with step-by-step guidance
• Helps improve incident response and decision-making
• No installation required (web-based tool)
• Downloadable materials and supporting resources

Usage and Access

Exercise in a Box is accessed online via the NCSC website.

To use it:

1. Visit the Exercise in a Box webpage
2. Choose a scenario relevant to your organisation
3. Download the exercise materials
4. Run the session internally with a facilitator

The exercises are designed to be flexible and can be adapted for different team sizes and levels of technical knowledge.

Pros

• Completely free and government-backed
• Easy to run with minimal technical knowledge
• Practical, real-world cyber security scenarios
• Helps build team awareness and preparedness
• No software installation required

Cons

• Requires time and coordination to run sessions
• Not an automated or continuous training platform
• Limited interactivity compared to paid simulation tools
• Outcomes depend on how well the exercise is facilitated

Ideal For

Exercise in a Box is ideal for SMBs and organisations looking to improve cyber security awareness and incident response without investing in expensive training platforms. It is particularly useful for teams that want hands-on, scenario-based learning in a simple and accessible format.

8. NCSC Early Warning

What is it: Cyber Threat Monitoring & Alerting Service

Website: https://www.ncsc.gov.uk/section/active-cyber-defence/early-warning

Overview

NCSC Early Warning is a free cyber security service provided by the UK’s National Cyber Security Centre (NCSC). It is designed to notify organisations of potential cyber threats affecting their networks, such as malware infections, phishing activity, or exposed vulnerabilities.

The service works by monitoring a range of trusted data sources and threat intelligence feeds. When suspicious activity related to your organisation is detected, alerts are sent to help you take action before significant damage occurs.

Key Features

• Free, government-backed threat intelligence service
• Alerts for suspicious activity (e.g. malware, phishing, vulnerabilities)
• Uses multiple trusted data sources and feeds
• Early notification of potential compromises
• Helps organisations respond quickly to threats
• Simple email-based alerting system
• No software installation required

Usage and Access

NCSC Early Warning is accessed online and requires registration.

To use it:

1. Sign up via the NCSC website
2. Register your organisation’s domains and IP addresses
3. Verify ownership of those assets
4. Receive alerts via email when threats are detected

The service runs continuously in the background once set up.

Pros

• Completely free and backed by the NCSC
• Provides early visibility of potential threats
• Easy to set up and use
• No infrastructure or software required
• Useful for improving security monitoring

Cons

• Reactive alerts rather than full real-time monitoring
• Limited detail compared to commercial threat intelligence platforms
• Requires correct setup (domains/IPs) to be effective
• Does not actively block or remediate threats

Ideal For

NCSC Early Warning is ideal for SMBs and organisations looking for a simple, no-cost way to gain visibility into potential cyber threats. It is particularly useful for organisations without dedicated security monitoring tools, helping them identify risks early and take action quickly.

9. OpenSCAP (Open Source)

What is it: A security baseline assessment tool

Website: OpenSCAP

Overview

OpenSCAP is an open-source security automation tool designed to assist with the assessment, measurement, and enforcement of security baselines, especially good for attack surface assessment exercises. It is based on the Security Content Automation Protocol (SCAP) and provides a range of functionalities, including vulnerability scanning, configuration auditing, and compliance checking against known security standards.

Key Features

• Compliance checking against security standards (e.g., PCI-DSS, HIPAA, STIG)
• Vulnerability scanning and reporting
• Configuration auditing
• Automated and customizable remediation scripts
• SCAP content authoring and validation tools

Usage and Installation

OpenSCAP can be installed on various Linux distributions. Installation typically involves using the package manager to install the openscap package and related tools. Detailed installation instructions and guides are available on the OpenSCAP website. Once installed, users can run scans and generate reports through command-line tools or the graphical SCAP Workbench.

Pros

• Open-source and free to use
• Comprehensive compliance and auditing features
• Supports a wide range of security standards
• Flexible and customizable
• Strong community support and documentation

Cons

• Requires technical knowledge for setup and use
• Primarily targeted at Linux environments
• Limited user interface for complex configurations

Ideal For

OpenSCAP is ideal for SMBs and larger organisations that need to ensure compliance with various security standards and perform regular security assessments. It is particularly beneficial for IT and security teams with the technical expertise to leverage its full capabilities. OpenSCAP is suitable for businesses seeking an open-source, flexible, and comprehensive solution to automate their security compliance and auditing processes.

10. Nmap (Open Source)

What is it: Network discovery tool

Website: Nmap

Overview

Nmap (Network Mapper) is an open-source network discovery and security auditing tool. It is widely used for network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets to determine what hosts are available on the network, what services those hosts are offering, what operating systems they are running, what type of packet filters/firewalls are in use, and many other characteristics.

Key Features

• Network discovery and inventory
• Port scanning and service detection
• OS detection and version detection
• Scriptable interaction with the target
• Extensive output formats and logging

Usage and Installation

Nmap can be installed on various operating systems, including Linux, Windows, and macOS. Installation typically involves downloading the appropriate installer from the Nmap website and following the setup instructions. Once installed, Nmap can be run from the command line, and users can perform scans using a variety of options and parameters to tailor the results to their needs.

Pros

• Free and open-source
• Versatile and powerful scanning capabilities
• Extensive documentation and community support
• Supports a wide range of operating systems
• Regularly updated with new features and enhancements

Cons

• Command-line interface may be challenging for beginners
• Can be resource-intensive on large networks
• Requires understanding of network protocols for effective use

Ideal For

Nmap is ideal for SMBs, IT professionals, and security enthusiasts who need a reliable tool for network discovery, security auditing, and vulnerability scanning. It is particularly beneficial for network administrators and security teams who have the technical expertise to utilize its powerful features. Nmap is suitable for businesses of all sizes that require a comprehensive, open-source solution for managing and securing their network infrastructure.

Conclusion

In summary, we’ve highlighted ten excellent free cyber security tools that can significantly enhance your business’s security posture. However, these are just the tip of the iceberg. If you require different solutions or additional features, a simple Google search can uncover many more options tailored to your specific needs. For those seeking expert guidance, consider partnering with a Virtual CISO (vCISO) who can provide strategic advice and help you select the best tools aligned with your business objectives and cyber security roadmap.