12 Best Web Application Firewalls in 2023

Web applications and APIs are crucial for businesses today, enabling key functions like ecommerce, user management, and data access. However, they also introduce major security risks if not properly protected. Successful attacks can lead to data breaches, financial fraud, system outages and more.

That‘s why implementing a web application firewall (WAF) is critical for security in the modern era. A WAF inspects all traffic to and from web apps and APIs, blocking common attack vectors like SQL injection and cross-site scripting. Leading solutions also incorporate machine learning to detect zero-day threats.

In this comprehensive guide, we evaluate the top 12 web application firewall services to consider in 2023.

How Does a WAF Work?

A WAF is deployed in front of web applications and APIs, acting as a protective barrier against attacks and unauthorized access. Here‘s an overview of how WAFs work:

Incoming traffic inspection – All HTTP/HTTPS requests are intercepted and analyzed for known attack patterns before reaching the application. This is done through preset rules and machine learning models.
Blocking threats – If a request contains suspicious characteristics, the WAF can block it completely. For less severe cases, it may just filter out the harmful portions while allowing benign traffic through.
Custom rule creation – WAFs allow administrators to define new rules tailored to their application‘s functionality. Rules can check for specific input patterns, URL structures, HTTP methods and more.
Alerting and reporting – Admins are notified of blocked attacks and suspicious activity. Detailed logs and analytics provide visibility into overall traffic and security trends.
Protection for common vulnerabilities – Most WAFs are designed to catch exploits against OWASP Top 10 vulnerabilities like SQLi, XSS, RCE, and insecure deserialization.
Zero-day threat detection – Machine learning models identify anomalies and block new attack techniques that rules alone would miss. Models improve over time as they gather data.

In summary, WAFs serve as the hardened outer walls protecting web apps and APIs. Their inspection and intelligence provide major improvements in application security.

Top 12 Web Application Firewalls of 2023

1. Cloudflare Web Application Firewall

Cloudflare is one of the most popular WAF solutions, known for its ease of use and role in Cloudflare‘s broad security ecosystem. Key features include:

Over 35 preset rulesets covering OWASP Top 10, bots, common CMS exploits, and more
Ability to customize rules using simple API queries and logic
Integration with Cloudflare Web Analytics to trigger rules based on visitor behavior
Runs on Cloudflare‘s global edge network for fast performance
Collective threat intelligence leveraged across Cloudflare‘s vast customer base
DDoS protection and CDN functionality (with certain plans)

Cloudflare also offers a free WAF plan for small sites, while paid plans start around $5/month. Overall, Cloudflare WAF is a top choice for its blend of strong protection and usability.

Cloudflare WAF dashboard

2. Akamai Kona Web Application Firewall

As a major CDN and cybersecurity vendor, Akamai incorporates robust WAF capabilities into its offerings. Highlights include:

Protections for OWASP Top 10, bots, credential stuffing, and zero days
Support for positive security models to allow known good traffic
Customizable using Akamai‘s Luna control framework
Integration with Akamai Web Application Protector for advanced policies
Real-time logging and analytics on the Akamai Luna portal
Can complement Akamai CDN and DDoS Protection

Akamai provides on-premises and cloud-based WAF deployments. With Akamai‘s strong security reputation, their solution is trusted by major enterprises. The level of customization also appeals to complex application environments.

3. AWS Web Application Firewall

As you‘d expect, Amazon Web Services offers a native WAF tightly integrated with AWS infrastructure like ALB load balancers, CloudFront CDN, and API Gateway. Benefits include:

Managed rulesets for OWASP Top 10, bots, common exploits
Rules can inspect headers, cookies, query strings, bodies, etc.
Real-time metrics and logging through Amazon CloudWatch
Simple JSON/API for config and automation
Can be deployed on CloudFront globally or regional ALBs
Integration with AWS Shield for DDoS protection

The AWS WAF is perfect for sites hosted on AWS that want a managed WAF solution. It provides reliable protection without needing external platforms or complex management overhead. Costs are based on usage, starting at $0.60 per million requests.

4. Microsoft Azure Web Application Firewall

Microsoft also offers its own robust WAF integrated with Azure infrastructure and services. Highlights:

Built-in protection for OWASP Top 10 vulnerabilities
Bot protection with Azure Bot Manager integration
Layer 7 load balancing capabilities
Custom rules can be created using ModSecurity syntax
Centralized logging and analytics via Azure Monitor
Tight integration with Azure Application Gateway
Simplified administration through Azure Portal

For applications hosted on Azure, the Azure WAF is a natural choice that allows you to manage WAF policies alongside your other application resources and configs. Azure also offers DDoS Protection that can complement the WAF. Pricing starts around $0.30 per GB of traffic processed.

5. Imperva Web Application Firewall

Imperva markets itself as a WAF focused on accuracy and low false positives. Features include:

Protection tuned for minimal business impact
Stacked analytics to reduce false positives
Flexible deployment options: cloud, on-premises, hybrid
Dynamic profiling to learn application behavior
Customizable security policies
Integrated DDoS mitigation
Security research team continually enhances protections

Imperva is a good choice for organizations that value precision and control around their WAF policies. The combination of dynamic profiling, configurable security levels, and expertise helps avoid incorrectly flagging valid traffic while still blocking true threats.

6. Barracuda Web Application Firewall

Barracuda WAF touts robust application security paired with user-friendly management. Capabilities include:

Broad coverage against OWASP Top 10, bots, DDoS and more
WYSIWYG editor and REST API for config
Integration with WAAP Manager for centralized control
Behavioral analysis to detect zero days without rules
Virtual patching to protect unpatched apps
Load balancing features
Web scraping and rate limiting policies
On-premises, cloud, and hybrid deployment options

Barracuda is ideal for organizations that need strong protections across a variety of deployment models. The behavioral analysis engine combined with easy management makes it appealing for diverse, complex environments.

7. F5 Networks BIG-IP Application Security Manager

The F5 ASM (formerly known as BIG-IP ASM) is a robust, full-featured WAF module available for F5‘s BIG-IP application delivery controllers. It provides:

Comprehensive coverage for latest threats
Behavioral, protocol, and traditional signature analysis
Powerful customization using iRules and iControl
Integrated DDoS mitigation
Role-based access control (RBAC)
BIG-IQ integration for centralized management
Can complement other BIG-IP services like load balancing

With F5‘s strong enterprise heritage and focus on infrastructure services, the ASM appeals to organizations with advanced needs or large-scale environments. The ability to leverage broader F5 services is also a plus.

8. Citrix Web App Firewall (formerly NetScaler ADC)

Citrix Web App Firewall is available as a module on Citrix‘s NetScaler ADC appliances, combining load balancing, content switching, and robust security. Highlights:

Layer 7 DoS protection
Hardware-based performance optimizations
Integration with other NetScaler services
API-driven automation options
Template-based policy creation
Custom reporting capabilities
Patent-pending policies to reduce false positives

For companies already leveraging NetScaler for application delivery, integrating its WAF capabilities is a logical next step. Citrix also touts the performance benefits of running security on dedicated NetScaler hardware. Useful for massive scale and latency-sensitive apps.

9. Sucuri Web Application Firewall

Sucuri WAF is a popular cloud-based solution focused on balancing strong protection with ease of use. Benefits include:

Broad signature database covering 200,000+ malware variants
Zero day protection using machine learning
Custom rules can augment default policies
Simplified PCI compliance
Monthly auto-tuning based on traffic patterns
Website acceleration via global CDN
Integrated DDoS mitigation
Monitoring for targeted attacks

With its wealth of signatures andautomated tuning, Sucuri is ideal for organizations that want robust, managed security without the hassle of extensive policy configuration. Monthly pricing starts at $99 for smaller sites.

10. Apptrana Web Application Firewall

Apptrana combines WAF capabilities with web vulnerability scanning and other application monitoring. It provides:

Runtime application self-protection (RASP) against zero days
Compliance heat maps highlighting policy gaps
Integrated CDN for acceleration
Web attack reports sent to your security team
Bot mitigation and rate limiting
Microservice support and API security
Masks vulnerable application issues from users

Apptrana‘s scanning integration helps enforce security best practices by highlighting risks in code or configurations. For organizations emphasizing DevSecOps, it‘s a compelling one-stop solution.

11. Signal Sciences Next-Gen WAF

Signal Sciences Next-Gen WAF emphasizes real-time threat visibility, compliance readiness, andDevSecOps integration. It delivers:

-granular forensic insight into blocked and allowed traffic

-developer-friendly APIs and SDKs

-Slack notifications and integration with SIEMs

-flexible, lightweight deployment without changes to app code

-coverage including SQLi, XSS, RCE, injection flaws

-support for legacy and modern applications alike

Signal Sciences breaks from traditional WAF models by providing unparalleled observability into activity for security teams and developers. For organizations practicing DevSecOps, this level of collaboration and transparency is highly valuable.

12. Reblaze Web Application Firewall

Reblaze is a relative newcomer delivering next-gen WAF capabilities focused on precision, automation, and rapid deployment. Key features:

Powerful AI engine to minimize false positives
Easy setup requiring no vendor assistance, rules, or tuning
Real-time traffic visualization and anomaly detection
Integrations with Slack, Datadog, Splunk and more
Bot mitigation, rate limiting, IP reputation
Full-stack protection including APIs and microservices

Reblaze emphasizes its AI engine‘s ability to accurately filter malicious traffic without manual intervention. For lean security teams that want strong application security without hands-on overhead, Reblaze is compelling. Plans start at $599/month.

Key Considerations for Choosing a WAF

With the top options laid out, here are some key criteria to consider when selecting a WAF provider:

Deployment Models

Cloud/SaaS – Managed WAF where vendor handles servers and maintenance. Easy to implement and scale.
On-premises appliances – Hardware installed in your environment. Provides control and can integrate with infrastructure. More complex.
Hybrid – Combine cloud and on-premises for flexible deployment.
Reverse proxy vs. IDS/IPS – Some WAFs function as full proxies while others are passive IDS/IPS.

Protection Scope

OWASP Top 10 and common attacks – SQLi, XSS, RCE, etc. are table stakes. Assess coverage.
Zero days and unknown threats – AI and behavioral detection are important for full protection.
APIs and microservices – Modern apps require API-aware policies.
Bot threats – Bot management is increasingly crucial.
DDoS – Some WAFs bundle DDoS mitigation, while others leave it separate.

Management Capabilities

Rules customization – Ease of tailoring policies to your needs. Languages and UI vary.
Centralized admin and logging – Unified visibility and control across multiple apps.
Alerting integration – Alert routing to SIEM, Slack, PagerDuty etc.
Automation and CI/CD – Programmatic control for infrastructure as code.
Analytics/reporting – Dashboards and visualizations for monitoring effectiveness.

Performance Optimization

Latency overhead – Processing inbound traffic adds latency. Look for optimized WAFs.
Scaling – Ability to smoothly handle traffic spikes.
Caching and CDN – Some WAFs optimize and cache traffic like a CDN.
Load balancing – Integrated load balancing improves reliability.

Cost

Monthly subscription pricing is common, with tiers based on number of apps, WAF features, and traffic volume.
Cloud-based WAFs offer pay-as-you-go models scaling with usage.
On-premises WAFs require upfront hardware costs but avoid recurring fees.

The Verdict

Implementing a robust web application firewall is one of the most impactful steps organizations can take to improve security posture. Leading WAFs combine powerful protections with usability and automation to safeguard critical web apps and APIs.

Cloud-based WAF solutions are excellent for rapid deployment with minimal maintenance overhead. On-premises appliances provide deeper infrastructure integration for complex environments. And many vendors offer hybrid models spanning both.

Covering core vulnerabilities like SQLi and XSS is just a starting point. Advanced behavioral analysis, machine learning, bot mitigation and strong analytics separate the best enterprise-grade WAFs.

For security teams looking to level up their defenses, a modern full-featured web application firewall is a must-have. Carefully evaluate options to find the best fit for your organization‘s needs and infrastructure. With critical applications and data on the line, a WAF is one of the smartest security investments you can make.