There are a variety of free WAFs available to secure your web apps. The best thing about open-source WAF is that you may customize the coding to fit your needs.

Web application firewalls are essential to your defensive approach since they defend against SQL injection, cross-site scripting (XSS), and cookie poisoning. There are numerous free WAFs available to secure your web apps. The nice thing about open-source WAF is that you may customize the coding to suit your needs.

Commercial WAF can be costly, so if you’re seeking a free way to defend your app with WAF, the open-source Web Application Firewall listed below can assist.

Let’s get started. 

8 Top Web Application Firewalls In 2022

The following is a list of the best web application firewalls.

1. ModSecurity  

Among the open-source web application firewalls, ModSecurity is a better option to choose. It comes with a slew of options that you may use to secure your web apps. ModSecurity allows you to customize the tool’s capabilities to meet your requirements.

ModSecurity has grown to provide a wide range of HTTP and response filtering capabilities and other security features on a variety of platforms, including apache HTTP server and Nginx.

ModSecurity’s open-source community is active and distributes updates regularly. It provided a console for storing, searching, and viewing the event. ModSecurity gives you the entire control over the tool’s capabilities, allowing you to tailor it to your specific requirements.

2. NAXSI

NAXSI is Nginx Anti-XSS & SQL Injection. It’s a third-party Nginx module that’s available as a package for various UNIX-like platforms. To begin, the tool is a popular reverse proxy firewall with simple rules.

NAXSI does not protect multiple attacks. However, it is the finest free online web application software for defending against common web application vulnerabilities such as Cross-Site Scripting and SQL injection.

Instead of the full-fledged apache engine utilized by ModSecurity, NAXSI uses the compact and performant reverse proxy engine of the Nginx web server. Because the patterns are so simple, they may match genuine requests. It is the responsibility of the NAXSI administrator to implement particular rules that will allow acceptable behavior.

3. WebKnight

WebKnight is a GNU General Public License-compliant web application firewall for IIS and other web servers. The suite of tools scans all requests and filters them based on the administrator’s rules. WebKnight will control and safeguard the webserver if an alert is raised.

WebKnight instead uses security filters to guard against buffer overflow, SQL injection, directory traversal, character encoding, and other threats. WebKnight will be able to save your server from all known and unknown assaults in this way.

WebKnight can work directly with the web server, allowing it to perform more than other firewalls and intrusion detection systems, such as inspecting encrypted traffic, because it is an ISAPI filter.

4. Shadow Daemon

Shadow Daemon is a web application firewall that filters out harmful intent, detects logs, and stops attacks on web programs. It receives the same input as the web application, making it nearly impossible to avoid detection by obfuscating the assault. Most other web application firewalls are further away from the web application than Shadow Daemon.

You may customize open-source software to make your firewall. Installing the Shadow Daemon is simple and takes only a few minutes. It has an interface through which you can administer and control this WAF. It is compatible with the PHP, Perl, and Python programming languages.

5. AppTrana

AppTrana is a fully managed WAF that includes optimized core collected rule sets, a CDN, and cloud content acceleration. You should route your traffic through the interface’s service, housed on AWS data centers in various regions.

Custom rules and policy updates are also available, with zero false positive assurances and promises. AppTrana provides a WAF that is simple to set up.

AppTrana assists in filtering requests from specific geo-locations and IP addresses and providing a daily report with a summary of stopped threats. It’s also good at preventing DDoS attacks. It searches for application-layer vulnerabilities, manages Bot Mitigation service, and provides risk-based protection.

6. Citrix WAF

Citrix WAF, formerly known as NetScaler, has features to analyze all bi-directional traffic, including SSL-encrypted communication. It safeguards online apps and websites against known and unknown vulnerabilities and application-layer and zero-day threats.

Citrix Web App Firewall features an easy-to-use UI that allows anyone to use it. Citrix WAF protects your internet-based services and ensures high availability. Citrix WAF provides robust protection without slowing down web application performance.

Enterprises can perform deep packet inspection of online protocols such as HTTPS, HTTP, and XML using the Web Application Firewall’s functionality.

7. Lua-resty-waf

Lua-resty-waf is still in development. It’s an OpenResty stack-based reverse proxy WAF. The tools use the Nginx Lua API to evaluate HTTP requests and filter them out according to the customizable rules.

Lua-resty-waf analyses HTTP request data and processes it against a customizable rule structure using the Nginx Lua API. Additionally, lua-resty-waf comes with tooling for automatically translating existing ModSecurity rules, allowing users to extend Lua-resty-waf without learning a new rule syntax.

The open-source WAF is built for scalability and efficiency. To handle requests quickly, it uses the Nginx asynchronous processing model.

8. Imperva Cloud WAF

Imperva is a comprehensive web application security solution that includes all necessary elements to secure application security and integrity. The Imperva web application firewall’s online version serves as a proxy server, capturing and cleaning all incoming traffic before forwarding it to the protected web server.

Other web enhancement services, such as a content delivery network, are coupled with the Imperva Cloud WAF service. The WAF features a virtual patching service that applies all necessary patches to the protected system while the webserver is bouncing, ensuring site availability.

Imperva’s Cloud WAF comes with a managed service option that comprises professionals and technicians to run the security software.

Final Thought

Premium firewalls are the most acceptable option for serious security against internet dangers. Installing free source WAF is an excellent option for personal projects or projects that don’t require a lot of protection. However, choosing the most acceptable Web Application Firewall is not as simple as it appears, and it is recommended that you test each solution on your own.