Best Web Application Firewall in 2025

What is Web Application Firewall?

A Web Application Firewall (WAF) is a protective tool for web applications to monitor incoming traffic and protect them against online threats. It is the first layer of defense between an app and the internet traffic. It identifies and obstructs malicious HTTP/S traffic such as SQL injection, XSS, and DDoS attacks to any web application. It also prevents the outflow of unauthorized data from your web application.

Additionally, the web app firewall enables access controls and offers real-time monitoring and logging capabilities for analysis. When combined with secure coding practices, it effectively enhances the overall security of web applications.

How Does Web Application Firewall Work?

A Web Application Firewall works by interfering and analyzing incoming HTTP/HTTPS requests and outgoing responses between a web application and its users. Here's how it operates:

• Traffic Inspection: It examines all incoming web application traffic, including request headers, parameters, and payload data.
• Rule-Based Filtering: It compares incoming data against known threat patterns, effectively identifying malicious or suspicious traffic based on predefined security rules.
• Threat Detection: It utilizes techniques such as signature-based detection and anomaly detection to detect potential threats such as SQL injection, cross-site scripting (XSS), and other common web application attacks.
• Blocking and Filtering: When the firewall succeeds in detecting malicious traffic, it proactively blocks or filters such traffic before it reaches the web application, preventing potential harm.
• Whitelisting and Blacklisting: Administrators can configure the firewall to allow trusted IP addresses and disallow known malicious entities.
• Virtual Patching: In situations where the web application has known vulnerabilities, but the patching process is delayed, it can apply temporary virtual patches to reduce risks until the application is updated.
• Logging and Monitoring: It maintains comprehensive logs of web traffic and security events, enabling administrators to analyse and respond effectively to potential threats.

What are the Features of Web Application Firewall?

• Attack Signature Databases: Web Application Firewall heavily relies on databases containing attack signatures. It follows patterns that indicate malicious traffic, including server responses, and known malicious IP addresses. However, these databases were less effective against new or unknown attacks.
• AI-Enhanced Traffic Pattern Analysis: AI algorithms enable behavioral analysis of traffic patterns, comparing them against different traffic types to detect anomalies that might indicate an attack. This allows the detection of attacks that do not match known malicious patterns.
• Customization: Security rules can be pre-defined to application traffic, allowing organizations to customize Web Firewall behavior as per their requirement and avoid blocking legitimate traffic.
• Application profiling: It evaluates the typical requests required for any application structure and allows data type accordingly. It could be URLs or values that need necessary permission from the web app firewall to enter.
• Correlation engines: It analyze the incoming traffic and ensure if it should be blocked or not. It keeps track of past attacks and detects malicious attacks through a set of custom rules.
• DDoS Protection Platforms: Cloud-based platforms, such as SaaS products and Amazon Web Services (AWS) can be integrated with WAF to protect against Distributed Denial of Service (DDoS) attacks. It can transfer detected DDoS traffic to this platform, which is capable of handling large volumes of attacks.
• Content Delivery Networks (CDNs): Deployed at the network edge, a cloud-hosted application firewall can provide a CDN to cache the website, enhancing its load time. There are several globally distributed points of presence (PoPs) and CDNs are deployed here. When a user visits a particular website, he is served from the closest PoP. This increases the website load time for the user, lowers down the burden on servers and increases security.

What are the Benefits of Web Application Firewall?

It comes with the following benefits:

• Web Application Security: These are built to protect web applications against a range of cyber threats, such as SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF), and other common attacks.
• Vulnerability Management: These can apply virtual patches to known vulnerabilities in web applications, reducing the risk of exploitation while developers address the underlying issues.
• Minimized Downtime: By proactively preventing successful attacks, these help minimize application downtime, ensuring uninterrupted service for legitimate users.
• Compliance Assistance: Setting it up helps organizations in meeting industry and regulatory compliance requirements concerning web application security.
• Bot Defense: It detects and blocks malicious bots, automated scanners, and web scrapers attempting to access or steal sensitive data.

What are the Types of Web Application Firewall?

There are three types of Web Application Firewall:

• Hardware-based WAF: As the name suggests, it is deployed through a hardware appliance and installed within the local area network (LAN) close to the web and application servers. This type involves fast speed and high performance. This type is suitable for large organizations, fetching thousands of daily users on their platform.
• Software-based Firewall: This is installed virtually on a virtual machine. All elements, however, are the same as are in the hardware-based application firewall. This is a more flexible option as the virtual machine can also be deployed in the cloud. This type is suitable for organizations with cloud-based web and application servers, such as hosting providers and data centers.
• Cloud-based Firewall: This is the latest generation of web app firewall that is directly managed by a service provider in the form of SaaS (Software-as-a-Service). Its components are in the cloud and there is no use of any virtual machine for installation. Small and medium-sized businesses are its most probable clients.

What are the Examples of Web Application Firewalls?

• AWS: Amazon Web Services is a cloud-based Web Application Firewall that protects web applications and APIs from common threats like SQL injection and XSS, integrating well with AWS services.
• Azure: Microsoft Azure Web App Firewall safeguards web apps from malicious traffic with custom rules and predefined protection against known vulnerabilities.
• Imperva: Imperva's standalone app firewall defends against threats and zero-day attacks, deployed on-premises or on the cloud.
• Akamai: Akamai's cloud-based Web Application Firewall uses a global network to protect against online threats and DDoS attacks, integrating with their CDN services.
• Cloudflare: Cloudflare's easy-to-set-up WAF offers protection against web app attacks and DDoS, leveraging their CDN and caching capabilities.

5 Top Web Application Firewalls

Products	Best For	Pricing
Sucuri WAF	Website security and protection against DDoS attacks.	Starting at INR 13999
NGINX Plus	High-performance web applications and load balancing.	Available on request
Codeigniter	A PHP framework with built-in security features for web application development.	Available on request
Laravel	Security practices and modern web application development.	Available on request
Radware AppWall	Protecting web applications against various cyber threats.	Available on request

What are the Factors While Choosing the Best Web Application Firewall?

When choosing the best Web Application Firewall for your needs, consider the following factors:

• Security Features: Go for a web firewall with robust security features, safeguarding against common web vulnerabilities like SQL injection, XSS, and OWASP Top 10 threats.
• Deployment and Management: Choose a firewall that offers easy deployment and management, especially cloud-based solutions for streamlined setup and automated operations.
• Performance Impact: Evaluate the WAF's impact on web app performance, aiming for minimal latency to maintain a smooth user experience.
• Threat Intelligence: Ensure the WAF receives regular updates with the latest threat intelligence to stay effective against emerging risks.
• Reporting and Analytics: Prioritize WAFs with comprehensive reporting and analytics, enabling a better understanding of your app's security and identifying attack trends.
• Integration and Compatibility: Verify seamless integration with your existing infrastructure, web servers, load balancers, CDN, and other relevant components.
• Cost-effectiveness: Evaluate total ownership costs, including licensing, infrastructure, and maintenance, to find a WAF that aligns with your budget.