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Top 10 Best WAF Solutions


Sophisticated attacks and complex environments are raising the bar for security standards, with known and unknown vulnerabilities becoming increasingly more challenging to pre-empt. The massive ChatGPT data leak has recently ensured web application security remains at the forefront of everyone’s minds.


In response, demand for WAFs is surging 14% year-on-year, showing that companies are taking protection against the OWASP Top 10 and zero-day attacks seriously. The next colossal obstacle is to decide which WAF is best for you, which is precisely what we will answer in this article.


What is a WAF Solution?

A Web Application Firewall (WAF) filtering layer monitors, identifies, and blocks suspicious traffic accessing your web app to guard against attacks like cross-site scripting (XSS), SQL injection, and file inclusion. Each HTTP request passes through your WAF before reaching the server, weeding out malicious traffic via a reverse proxy method based on rules or policies.


Types of WAF Solutions

  • Cloud-based: Turnkey deployment option offered by cloud providers as managed security-as-a-service. A popular method that constantly monitors threat intelligence updates and responds in real-time based on your security policies.

  • Network-based: Also known as hardware-based WAF since it is installed locally on your organization's network. Used to minimize latency during data breach instances and can be more expensive.

  • Host-based: Also known as software-based WAF, this method can be run on-premises or in a cloud environment as a cost-effective option.


Benefits of WAF Solutions

Here are just some of the benefits of WAF, complemented by security-as-code.

  • Automatically enforces permissions and access controls to authorized users, providing better visibility across endpoints.

  • Automates filtering and blocking of malicious traffic, allowing only valid requests to reach your network or server.

  • Monitors your traffic and endpoints to detect exploitable vulnerabilities.


Key Features to Look For in a WAF Solution

Below, we've compiled a short list of capabilities that an effective WAF solution must have.

  • Assess every HTTP request your application gets to block suspicious traffic based on your preset rules.

  • Block zero-day attacks without being signature-dependent – although only a few solutions, including open-appsec, do this.

  • Normalize incoming requests and outgoing responses against the defined set of rules.

  • Detect anomalies through machine learning models and block them for suspicious activity.


How We Tested the Best WAF Solutions

To conduct a thorough evaluation, we implemented an in-depth test principle by triggering malicious and valid web requests at different WAFs. We used the following data set to test the products for web application security:

  • 973,964 legitimate HTTP requests from 185 real websites in 12 categories.

  • 73,924 malicious payloads from a broad spectrum of commonly experienced attack vectors.

We tested the solutions on two critical parameters:

  • Security quality: Denotes the WAF’s ability to accurately identify and prevent malicious requests.

  • Detection quality: The WAF’s ability to allow valid requests.


10 Top WAF Solutions

Tried and Tested WAF on the Market

Here are the solutions we comprehensively tested and what we thought of them.


Microsoft Azure Application Gateway WAF is integrated with the Azure Application Gateway and centralizes the security of your web apps against vulnerabilities. It can be deployed in one of three operational modes: detection, prevention, and custom.


Main features:

  • Detection of common application misconfigurations (for example, Apache and IIS).

  • Create custom rules to suit the specific needs of your applications.

  • Geo-filter traffic to allow or block certain countries/regions.

Best for: Organizations that need scalability and interoperability with other Azure services.

Pricing: Pay-as-you-go.

Test results:

  • Security Quality (True Positive Rate): 98.547%

  • Detection Quality (False Positive Rate): 38.346%

  • Balanced Accuracy: 80.1%

Review: It is really helpful in terms of securing one's applications. It protects [against] the Open Web Application Security Project (OWASP) top 10 security risks.



open-appsec is an open-source web application and API security solution that leverages machine learning algorithms to protect your online applications against OWASP Top 10 attacks, such as broken access control and security misconfiguration. Unlike competitors, it is not signature-dependent, so it can also prevent zero day attacks pre-emptively.


Main features:

  • Analyzes HTTP/S requests continuously using ML engine to identify or block parameter tampering, privilege elevation attacks, and path traversal attacks.

  • Allows flexible SSL encryption configuration and enforces forward secrecy ciphers and HSTS.

  • Produces minimal false positives and can be used as the primary engine for the actual detection/prevention of attacks.

Best for: Both web applications and API security.

Pricing: Free and open source.

Test results:

  • Security Quality (True Positive Rate): 98.895%

  • Detection Quality (False Positive Rate): 4.253%

  • Balanced Accuracy: 97.32%

Review: open-appsec/CloudGuard AppSec protects our web applications and prevents OWASP Top 10 attacks. It is also automatically checked and creates a risk score.




AWS WAF is an option from Amazon Web Services (AWS) that can be deployed on AWS CloudFront, the Application Load Balancer (ALB), or an AWS API Gateway, offering flexibility depending on your architectural needs.


Main features:

  • Custom rule creation or set up pre-configured rules using the AWS Management Console.

  • Integrates easily and seamlessly with other AWS services.

  • Only pay for what you use, and you can optimize AWS WAF pricing to mediate costs as you scale.

Best for: Environments based on other AWS services.

Pricing: Web ACL is $5/month, along with a $1/WAF rule and request.

Test results:

  • Security Quality (True Positive Rate): 76.434%

  • Detection Quality (False Positive Rate): 4.383%

  • Balanced Accuracy: 86.03%

Review: AWS WAF has various features to protect our applications & API against DDoS attacks, unknown exploits & bots.




Cloudflare WAF is a cloud-based solution that operates as part of Cloudflare’s broader suite of CDN, DNS, and DDoS protection services, giving it the advantage of a highly distributed network to help stop threats closer to the source.


Main features:

  • Provides a single, integrated rules engine for effective and uniform security.

  • Provides analytics to help you understand real-time attack insights.

  • Has managed rulesets for automated protection against recognized dangers.

Best for: Integration with CDN (content delivery network) and getting live analytics.

Pricing: The pro plan starts at $20/month.

Test results:

  • Security Quality (True Positive Rate): 69.297%

  • Detection Quality (False Positive Rate): 0.055%

  • Balanced Accuracy: 84.62%

Review: Easy to use and out-of-the-box solution for a lot of sec issues. They provide many tools and features to enable your cloud services quickly.




Built on F5 technology, NGINX WAF is an open-source web server that can also act as a reverse proxy, load balancer, and HTTP cache. The solution integrates with various monitoring and analytics tools to help users gain real-time insights into web traffic and security events.


Main features:

  • ML-based behavioral analytics detect and block abnormal traffic patterns.

  • Can decrypt, inspect, and re-encrypt HTTPS traffic for thorough security analysis.

  • Designed to integrate directly into the NGINX stack.

Best for: Organizations that already use NGINX Plus for application delivery.

Pricing: Free and open source.

Test results:

  • Security Quality (True Positive Rate): 78.132%

  • Detection Quality (False Positive Rate): 2.01%

  • Balanced Accuracy: 88.06%

Review: F5 NGINX is free and open-source and can be used for all our web services. It is easy to implement, and we can set up our website within a minute.


ModSecurity is a popular open-source WAF solution supporting NGINX, Apache HTTP, and Microsoft IIS. It commonly uses the OWASP Core Rule Set (CRS), which offers protection against various attack vectors.


Main features:

  • Can use anomaly scoring to assign risk levels.

  • Provides extensive monitoring capabilities, allowing you to log HTTP traffic and analyze it in real-time.

  • Offers a lot of flexibility for users who are comfortable editing configuration files and writing custom rules.

Best for: The add-on for NGINX will reach end-of-life in July 2024. If this applies to you, it’s time to look for a ModSecurity alternative.

Pricing: Free and open source.

Test results:

  • Security Quality (True Positive Rate): 86.716%

  • Detection Quality (False Positive Rate): 10.604%

  • Balanced Accuracy: 88.06%

Review: You will be able to create very specific rules, thus optimizing the program's performance.


Other WAF on the Market

Here are a few more great WAF solutions that we didn’t test.




Imperva WAF is a cloud-based solution that specializes in DDoS protection. Users can configure custom security rules to tailor the WAF to their specific web/cloud-native application security requirements, enhancing its ability to accurately identify and block malicious requests.


Main features:

  • Designed to help businesses meet various compliance requirements, including PCI DSS.

  • Integrated CDN helps improve site performance.

  • Cloud-based architecture ensures that the service can scale to meet demand.

Best for: Small to medium enterprises due to its flexibility and relatively low cost.

Pricing: Pro plan begins at $59 per site per month.

Review: Imperva WAF keeps your website safe from bad guys by stopping their sneaky attacks before they cause harm. But setting it up can be complex.




Akamai Site Defender is a cloud-based WAF that is easy to set up and manage. Built on Akamai's Intelligent Edge Platform, Site Defender leverages the company's globally distributed network to provide scalable and resilient security solutions.


Main features:

  • Provides comprehensive API visibility.

  • Uses AI and ML to adjust its protection mechanisms in real-time.

  • Provides live traffic insights for proactive detection.

Best for: Enterprises that experience very high traffic for their web applications.

Pricing: You can get a free trial, and the pricing is by inquiry.

Review: Less performance degrades while using the Akamai WAF. Easy setup while we were setting up our Ecom environment.




AppTrana is a managed WAF solution that often includes tuning the WAF to your specific application, which can help minimize false positives. Security experts manage and monitor your security configuration, and you'll have access to the support operations centre to reduce the burden on your internal team.


Main features:

  • Enables patches for critical vulnerabilities within 24 hours.

  • Offers rate-limiting features to protect against attacks like brute force.

  • Cloud-based architecture means that the service is scalable.

Best for: Small and medium businesses who might benefit from access to security expertise.

Pricing: Its most advanced plan is priced at $99/month.

Review: The response is very good. The AppTrana portal is very useful, built well, and gives all reports beforehand.




Fortinet FortiWeb is a WAF that offers specialized security features for protecting APIs and blocking or restricting access based on factors like known malicious IP addresses. It is designed to scale easily and fits into the broader Fortinet security ecosystem.


Main features:

  • Uses machine learning algorithms to detect anomalies.

  • Provides the ability to write custom rules.

  • Offers in-depth logging and reporting capabilities to help you track events.

Best for: Large enterprises for complete threat protection, as Fortinet’s larger FortiGate ecosystem offers a suite of compatible security products.

Pricing: The one-year standard package costs around $2,300.

Review: FortiWeb WAF has truly valuable features, one of which is that it provides the user with reliable, versatile, and affordable software for small, medium, and large companies.


Selecting a WAF Solution That’s Optimal For You

WAF solutions are an essential shield for your web applications against threats like SQL injection, cross-site scripting, DDoS attacks, zero-day attacks, and OWASP Top 10.


As much as it is crucial to implement a WAF, you must also invest time in evaluating WAF tools available in the market. Each solution has specific features, strengths, and weaknesses, and your decision should rely heavily on your organizational needs.


Try the open-appsec Playground today.



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