Web application firewalls monitor and filter web application traffic and protect web applications against attacks that exploit weaknesses in the application code and server structure.
A WAF is a critical component of a robust online application security strategy. WAFs can identify and prevent assaults on web application vulnerabilities, helping prevent data theft, service interruption, and reputational harm.
Here are the eight web application firewalls that stood out in our analysis of the WAF market.
- Fortinet FortiWeb
- Imperva WAF
- AppTrana
- Barracuda Web Application Firewall
- F5 Advanced WAF
- Microsoft Azure Application Gateway
- Cloudflare
- Wallarm WAF
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Comparing the top WAF solutions
The following table compares our top web application firewalls based on a few key features and the availability of free trials.
| Attack Signatures | DDoS Protection | Integrations | Free Trial | |
|---|---|---|---|---|
| Fortinet FortiWeb | ✔️ | ✔️ | SIEM, SOAR, DevOps tools | 15 days |
| Imperva WAF | ✔️ | ✔️ | SIEM, SOAR, DevOps tools | 30 days |
| AppTrana | ✔️ | ✔️ | SIEM | 14 days |
| Barracuda WAF | ✔️ | ✔️ | SIEM, SOAR, DevOps tools | 30 days |
| F5 Advanced | ✔️ | Detection | SIEM, SOAR, DevOps tools | Unclear |
| Azure Application Gateway | ✔️ | ✔️ | Azure services | 30 days |
| Cloudflare | ✔️ | ✔️ | DevOps tools | Unclear |
| Wallarm | Unclear | ✔️ | SIEM, SOAR, DevOps tools | Free tier of WAF for smaller plans |
Fortinet FortiWeb
Overall Reviewer Score
4.5/5
Pricing
4.5/5
Features
4.6/5
Usability and administration
4.1/5
Customer support
5/5
Fortinet FortiWeb protects online applications and APIs from OWASP’s Top 10 threats, distributed denial of service (DDoS) attacks, and malicious bot assaults. Its advanced ML-powered features increase security while reducing administrative costs.
This WAF solution provides anomaly detection, API discovery and protection, bot mitigation, and advanced threat analytics to identify the most serious threats across all protected apps.
Pros
Cons
- Microsoft Azure pricing: $0.93 per hour
- AWS pricing: $1.061 per hour for a t3.small instance
- Free trial: 15 days
- Web application protection: FortiWeb helps prevent OWASP top ten threats, bots, and other dangers.
- Advanced analytics: FortiWeb Cloud uses machine learning to detect attack patterns in your application environment and categorize those potential threats.
- Mitigating false positives: FortiWeb is designed to limit manual policy and exception management to reduce false positives.
- Native integrations: FortiWeb integrates with other solutions like FortiGate, FortiSandbox, and FortiSIEM.
Does your business need a firewall, but you’re unsure if WAF is the best solution? Check out our guide to the different types of firewalls next.
Imperva WAF
Overall Reviewer Score
4.1/5
Pricing
4/5
Features
3.6/5
Usability and administration
4.7/5
Customer support
4.5/5
Imperva is a cloud-based security solution that defends online applications against assaults such as SQL injection, cross-site scripting (XSS), and remote file inclusion (RFI). Imperva WAF provides comprehensive capabilities that enable multi-layered threat prevention, assuring the safety and availability of online applications.
Pros
Cons
- Pricing: Contact for quote
- Free trial: 30 days
- Policy creation: Imperva allows admins to create policies for websites on your account and set policies as the default so they apply to all sites added to the account.
- Protection for various apps: Imperva offers security for active and legacy applications, third-party applications, APIs and microservices, cloud apps, and more.
- Behavioral detection: Imperva uses traffic behavior patterns to detect and prevent zero-day attacks.
- OWASP Top 10 protection: Imperva’s cloud WAF helps your business stop cross-site scripting attacks and other Top Ten threats.
AppTrana
Overall Reviewer Score
4/5
Pricing
4.5/5
Features
4.1/5
Usability and administration
3.5/5
Customer support
4.3/5
AppTrana provides real-time protection against web application attacks by combining machine learning algorithms, security specialists, and a 24/7 security operations center.
Unlike typical WAF solutions, AppTrana provides a fully managed solution where AppTrana’s security professionals administer the WAF on the customer’s behalf. This is a good option for smaller teams looking for assistance with firewall management.
Pros
Cons
- Advance plan: Starts at $99 per application for a month when billed monthly
- Premium and Enterprise plans: Contact for a quote
- Demo: Contact to schedule
- 24-hour patching: AppTrana offers patch management so your team can stop zero-day threats in a timely manner.
- DDoS mitigation: AppTrana generates rate limits to help prevent DDoS attacks from overwhelming your systems.
- API security: AppTrana automatically documents APIs and helps you protect your them with both negative and positive security policies.
- Bot protection: Behavior-based bot tracking helps detect anomalous activity better and prevent attacks like credential stuffing.
Barracuda Web Application Firewall
Overall Reviewer Score
4/5
Pricing
4.3/5
Features
4/5
Usability and administration
3.5/5
Customer support
4.5/5
Barracuda Web Application Firewall is a hardware or virtual device that protects against numerous web application assaults and helps teams deliver applications safely. This is ideal for enterprises that demand a comprehensive and user-friendly WAF solution with advanced security capabilities such as bot protection and DDoS avoidance.
Pros
Cons
- Contact for quote: Custom pricing available
- Reseller pricing info: Contact Barracuda resellers for information on WAF-as-a-service
- Free trial: 30 days
- Bot protection: Barracuda detects advanced bots, including web scrapers, session trackers, and credential stuffers.
- API protection: The WAF protects REST/JSON and XML APIs from attacks through HTTP requests.
- Geo-based access restriction: The firewall can manage web access based on IP address geography so that only certain regions have access.
- Optimized attack signatures: Barracuda’s WAF combines signatures in groups so that the grouped signatures can detect attacks found in multiple signatures.
F5 Advanced
Overall Reviewer Score
3.9/5
Pricing
3.1/5
Features
3.8/5
Usability and administration
4.7/5
Customer support
4.1/5
F5 Advanced WAF goes beyond reactive security features like static signatures and reputation to identify and neutralize bots, safeguard passwords and sensitive data, and fight application denial-of-service (DoS).
This WAF option is a good choice for organizations with sophisticated web-based apps that require advanced security capabilities, such as automated threat detection and API protection.
Pros
Cons
- AWS cloud pricing: $5.202 per hour for a t3.medium instance
- Other reseller pricing available
- Pricing info from F5: Contact for quote
- Encryption security: F5 terminates SSL/TLS connections and decrypts and re-encrypts traffic to inspect threats more deeply.
- DoS protection: The advanced firewall automatically detects new or strange traffic and uses a feedback loop to mitigate a potential DoS attack.
- Credential protection: F5 Advanced masks data in users’ browser windows to protect usernames and passwords.
- API protection: F5’s API security features include rate limiting and policy rule enforcement.
Microsoft Azure Application Gateway
Overall Reviewer Score
3.8/5
Pricing
5/5
Features
3.2/5
Usability and administration
3/5
Customer support
4.5/5
Microsoft Azure Application Gateway WAF is a web application firewall service integrated with the Azure Application Gateway.
It provides centralized security for online applications against common exploits and vulnerabilities. Among the most frequent attacks protected by Azure are SQL injection, cross-site scripting, and cross-site request forgery.
Pros
Cons
- Pricing: Hourly cloud costs available from Azure
- Free Azure trial: 30 days
- Protection against common web attacks: Examples include command injection, HTTP request smuggling, HTTP response splitting, and remote file inclusion.
- Protection against HTTP protocol violations: Protocol violations or anomalies include missing host user-agent and accept headers.
- Exclusion lists: Azure’s WAF can omit specified request attributes from an evaluation if you need to allow a certain request for an application.
- Geo-filter traffic: Azure Application Gateway can allow or block certain countries/regions from gaining access to your applications.
Cloudflare
Overall Reviewer Score
3.7/5
Pricing
3.5/5
Features
3.9/5
Usability and administration
3/5
Customer support
4.8/5
Cloudflare WAF is a cloud-based web application firewall intended to protect websites and APIs from many forms of assault.
The WAF solution offers various security measures to assist in avoiding attacks, as well as performance and reliability benefits. Cloudflare WAF offers a unique combination of global network, machine learning, bot mitigation, user-friendly UI, and DNS security.
Pros
Cons
- Pro: $20 per month billed annually
- Business: $200 per month billed annually
- Enterprise: Contact for quote
- Data loss prevention: Cloudflare blocks responses that contain sensitive personal information, such as credit card numbers, or sensitive business data, such as API keys.
- API security: Cloudflare uses schemas or machine learning to prevent attacks on your APIs.
- Managed rulesets: These rules are preconfigured and help protect against zero-day attacks and sensitive data extraction.
- Custom rule creation: Admins can define their own rules to block specific traffic requests going to a zone.
Wallarm
Overall Reviewer Score
3.7/5
Pricing
4.6/5
Features
3.4/5
Usability and administration
4.5/5
Customer support
2.2/5
Wallarm WAF is an AI-powered web application firewall that protects APIs and apps in real time with cloud web application and API protection (WAAP). This includes comprehensive API support for REST, SOAP, WebSocket, graphQL, and gRPC.
With a single DNS update, Wallarm Cloud WAF secures your business’s apps, APIs, and serverless workloads.
Pros
Cons
- Wallarm Entry: $50,000.00 per year, available through AWS
- Wallarm Enterprise: $150,000.00 per year, available through AWS
- Virtual patching: A virtual patch prevents requests from any sources that aren’t allowlisted when your app has an unfixed vulnerability that could otherwise be exploited.
- API abuse profiles: Wallarm allows you to create profiles for individual applications that specify which bots to protect against for that application.
- Brute force protection: This feature requires configuration and allows you to block IP requests that exceed your predetermined limit over a set interval of time.
- Vulnerability assessment: Wallarm scans exposed assets, performs attack verification, and analyzes traffic requests and responses.
For more recommendations on deciding between different vendors, read our guide to choosing a WAF solution.
10 common features of web application firewalls
The best web application firewalls offer a range of features to protect web applications while making management easier. Buyers should look for a solution that best addresses their needs.
- API protection: WAF solutions safeguard APIs against unauthorized access and API-specific threats, like API injection and API scraping.
- Automated updates: WAF vendors automatically update their rules and signatures to offer faster protection against new threats.
- Bot protection: Using machine learning and behavioral analysis, WAF systems detect and block bot traffic that attempts to exploit web applications.
- Centralized administration console: WAF products provide a centralized administration console through which administrators can configure, monitor, and administer multiple WAF instances from one place.
- Customizable firewall policies: WAF solutions allow administrators to establish and enforce custom firewall policies to prevent unwanted access to web applications.
- Custom rule creation: WAFs enable administrators to build customized rules to guard against specific risks or to help their business comply with industry laws.
- Intrusion detection and prevention: WAF solutions detect and prevent web application assaults by combining signature-based and behavior-based methodologies.
- Real-time monitoring and warnings: WAF systems monitor web traffic in real time and send administrators alerts when suspicious behavior is discovered.
- Scalability: WAFs can manage significant levels of online traffic while also protecting against large-scale DDoS assaults.
- SSL/TLS encryption: WAF solutions include SSL/TLS encryption to protect online traffic from eavesdropping and interception.
How we evaluated the top WAF solutions
In selecting the WAF products for this list, we looked for those that offer an optimal combination of protection, scalability, ease of use, customization, integration, and support. We also considered factors like price, reputation, and customer feedback.
A product scoring rubric helped narrow the list to our final eight, of which Fortinet FortiWeb was the clear winner.
Evaluation criteria
The most important criterion was features, like custom rules and attack signatures. Next, we considered usability and administration features, such as documentation and training videos for new users. Finally, we looked at pricing — including free trials — and customer support offerings like phone channels.
- Features (35%): WAF features included traffic profiling, DDoS protection, and bot protection.
- Criterion winner: Fortinet
- Usability and administration (25%): This category examined product documentation, deployment options, and the availability of a managed service.
- Criterion winner: F5 and Imperva
- Pricing (20%): We considered free trials, including their length, and whether the firewall vendor provides transparent pricing info.
- Criterion winner: Azure Application Gateway
- Customer support (20%): This category took email, phone, and chat support into account, as well as 24/7 availability.
- Criterion winner: Fortinet
Bottom line: Web application firewalls
Web application firewalls (WAFs) are useful tools for protecting web apps from a range of threats, including SQL injection, cross-site scripting, and DDoS attacks. Each WAF tool has its own set of capabilities, strengths, and weaknesses.
Cloud-based WAFs are often less expensive and provide faster updates than on-premise WAFs. WAF solutions that include artificial intelligence and machine learning can offer more advanced and proactive protection against emerging threats. Ultimately, the best firewall will depend on your business’s specific needs.
If you’re specifically wanting protection against distributed denial of service attacks, check out our guide to the Best DDoS Protection Service Providers next.
