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Keeping Your Website Safe: What are Web Application Firewalls?

June 26, 2024

Web application firewall

Most businesses no longer operate strictly on a local network with in-house applications and software. At some point, your company connects to the internet, even if it’s for tasks as simple as email and payroll.

But whatever web applications you’re using, you’re opening yourself up to malicious activities that result in data leaks and potential financial losses for your organization. Running security systems like firewalls are a good way to keep web and mobile applications protected from threats online.

WAF systems analyze the HTTP traffic as it comes into the network, looking out for potentially damaging movement or anomalies in the data. When used with additional application protections, like secure web gateways, these tools provide better defense for overall operational web applications.

How a web application firewall works

WAFs can work off either a positive or negative security model. Under a positive model, the firewall operates from a whitelist that filters traffic based on permitted actions. Anything that doesn’t adhere to this is automatically blocked. Negative WAFs have a blacklist that blocks a fixed set of items or websites; everything else gets access to the network unless something specific is flagged.

Web application firewalls come with a number of features to protect data on the network, including:

  • Attack signature reviews. Databases within the WAF map patterns of malicious traffic, like incoming request types, suspicious server responses, or known malicious IP addresses to block both incoming and outgoing traffic.
  • Application profiling. By analyzing the structure of an application request, you and your team can review and profile URLs to allow the firewall to detect and block potentially harmful traffic.
  • Customization.Being able to update and change security policies means organizations can tailor firewalls and prevent only the most detrimental traffic.
  • DDoS protections. Distributed denial of service (DDoS) attacks occur when cybercriminals try to make an online service unavailable by using a brute force attack over multiple compromised devices. Some WAFs can be connected to cloud-based platforms that protect against DDoS attacks.

Types of web application firewall security

While WAF focuses on web-based applications, you can incorporate several different types of WAF into your security system. 

  • Cloud-based WAFs are some of the most affordable ways to implement these security systems. They usually have minimal upfront costs, along with a monthly subscription fee that means businesses of all sizes can enjoy the benefits that a WAF brings.
  • Hardware-based WAF must be installed on the local network server to reduce latency and make them highly customizable. But they also come with downsides – there’s a larger upfront cost to these firewalls, along with ongoing maintenance costs and resources needed.
  • Software-based WAFs, as an alternative to computer hardware, can be stored locally on a network server or virtually on the cloud. There’s lower upfront costs with these compared to hardware and there are customization possibilities that other WAFs may not have. However, they can be complex to install.

Web application firewall vs. firewall

A web application firewall is typically used to target web applications using HTTP traffic. A firewall is broader; it monitors traffic that comes in and out of the network and provides a barrier to anything trying to access the local server. They can be used together to create a stronger security system and protect a business’s digital assets.

Best web application firewalls 

WAFs are designed to protect web apps by monitoring and filtering traffic from specific web-based applications. They’re one of the best ways to safeguard business assets, especially when combined with other security systems.

To be included in the WAF category, platforms must:

  • Inspect traffic flow at the application level
  • Filter HTTP traffic for web-based applications
  • Block attacks such as SQL injections and cross-site scripting

Below are the top five leading WAF software solutions from G2’s Spring 2024 Grid Report. Some reviews may be edited for clarity.


The AWS WAF is Amazon’s answer to the need for protection against common web exploitations. Secure your business from application availability issues and compromised security, while consuming fewer resources within a cloud-based firewall.

What users like best: 

“AWS WAF comes with the best set of rules for filtering out malicious IPs. It is very easy to implement as we can create the rules using AWS protocol.”

- AWS WAF Review, Mugdha S.

What users dislike:

“AWS Shield advanced service needs an improvement to protect from every type of DDoS attacks as it failed twice to detect and protect our resources and systems. They were inaccessible during a DDoS attack simulation.”

- AWS WAF Review, Prashant G.

2. Imperva Web Application Firewall 

Imperva WAF is a leading web application firewall, providing enterprise-level protection against sophisticated online security threats. As a cloud-based WAF, your website and other digital devices can stay protected against applicator-level hacking attempts.

What users like best: 

“Imperva WAF keeps your website safe from bad guys by stopping their sneaky attacks before they cause any harm. It knows how to kick out those annoying bots that try to mess with your website, ensuring that only real people can access it.”

- Imperva WAF Review, Kaushik A.

What users dislike:

“Imperva WAF offers a range of security rules and policies. Some users have expressed a desire for more customization options. They may feel restricted by the available configurations and may require additional flexibility to tailor the WAF to their specific needs.”

- Imperva WAF Review, Nandini M.

3. Azure Application Gateway 

As an application-level WAF, Azure Application Gateway provides a scalable web front-end firewall for all levels of business. This Microsoft system manages traffic to web applications, with traditional load balancers operating at the transport level to route traffic based on source IP addresses and ports.

What users like best: 

“The wonderful advantages of this web traffic load-balancing tool include URL-based routing, autoscaling, the confidence we have in Microsoft's security measures, and an excellent uptime service-level agreement.”

- Azure Application Gateway Review, Mohit K.

What users dislike:

“Azure pricing can be complex sometimes, making cost estimation difficult. Sometimes there are problems getting quick and comprehensive help and there are service interruptions. It is also sometimes documented, which affects the functionality of the resource. Some services may have restrictions that affect certain requirements.”

- Azure Application Gateway Review, Akshat K.

4. Azure Web application Firewall

The Azure Web Application Firewall is a cloud-based service that safeguards web applications from web-hacking techniques like SQL injections and other security vulnerabilities like cross-site scripting. By inspecting all incoming and outgoing web traffic, the firewall can quickly protect your business from common exploits and vulnerabilities.

What users like best: 

“Microsoft's Windows firewall has a built-in feature that provides network protection by monitoring and controlling incoming and outgoing network traffic, which helps in protecting unauthorized access.”

- Azure Web Application Firewall Review, Praveen J.

What users dislike:

“Azure should work on providing a better architecture representation for how they are dealing with the vulnerability arising in cloud security.”

- Azure Web Application Firewall Review, Amrender S.

5. Cloudflare Application Security and Performance

As the world’s first connectivity cloud, Cloudflare Application Security and Performance protects millions of businesses worldwide with security, performance, resilience, and privacy services. Keep your business data safe from global cyberthreats with enterprise-level security features.

What users like best: 

“Cloudflare has been great in terms of securing and managing our domains and sites from one simple dashboard. It has provided great uptime and performance analytics to our websites very reliably. There are many more tools like speed testing, DNS records, caching, and routes that helped us monitor our site and user experience. Their customer support is as fast as their speed.”

- Cloudflare Review, Rahul S.

What users dislike:

“Rules are infrequently updated, false positives are common, and there may be performance and latency issues when using other hosting platforms.”

- Cloudflare Reviews, Sujith G.


Winning the web war!

Protecting your organization’s web application from cyber criminals should be a top priority. Using a web application firewall as part of your entire security system is one of the best ways to keep your data safe from malicious traffic and unauthorized access.

Get a better understanding of the traffic coming in and out of your network with network traffic analysis (NTA) software.

Web Application Firewall Software Protect your data!

Keep your business information safe with a web application firewall that stops cybercriminals in their tracks.

Web Application Firewall Software Protect your data!

Keep your business information safe with a web application firewall that stops cybercriminals in their tracks.

Keeping Your Website Safe: What are Web Application Firewalls? Web application firewalls (WAFs) are security tools that shield your web application data from cybercriminals. Learn more about using WAFs in business.
Holly Landis Holly Landis is a freelance writer for G2. She also specializes in being a digital marketing consultant, focusing in on-page SEO, copy, and content writing. She works with SMEs and creative businesses that want to be more intentional with their digital strategies and grow organically on channels they own. As a Brit now living in the USA, you'll usually find her drinking copious amounts of tea in her cherished Anne Boleyn mug while watching endless reruns of Parks and Rec.

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