In case you’re beginning your career as a security professional, you will come across multiple types of security products, and Web Application Firewalls will be among them. Then, you may question: what’s a Web Application Firewall?

A Web Application Firewall is a special type of firewall to monitor and protect against incoming threats. But it’s different than a conventional firewall. So, what’s the difference? Why is it important for organizations? In this post, you’ll find the answers to these and more such questions about WAFs. Read on.

What is a Web Application Firewall?

A Web Application Firewall (WAF) is a firewall for web applications. It’s built to filter and monitor web traffic between a web application and its users accessing it through an intranet or the Internet. As with any firewall, it’s more like a shield between an application and its users, especially malicious people.

However, it’s different than a regular firewall installed in your system. It’s usually set up to protect servers with a single or a group of web application(s) against various types of attacks by inspecting the application’s traffic. However, a regular firewall only works as a safety barrier between clients and servers.

A Web Application Firewall usually protects web applications from various types of attacks including but not limited to cross-site forgery, cross-site scripting, and file deletion or manipulation. Moreover, it can be customized to detect and inspect advanced attacks like buffer overflows and session hijacking.

It’s a Layer 7 (Application) defense per the OSI Model, so it doesn’t mitigate or protect against all types of attacks. That’s why, it’s normally part of a set of security tools that conjointly creates a full-fledged defense to fight against a wide range of threats such as malware attacks, zero-day exploits, etc.

Web Application Firewall is typically useful to organizations providing cloud or web products and services. For example, an e-commerce website or a banking application hosts a WAF to monitor all incoming traffic and neutralize all harmful traffic to prevent data theft, downtime, or more serious consequences.

Types of Web Application Firewalls

Web Application Firewalls come in multiple specifications and provide a little different list of advantages per specification. That said, let’s check out the three types of Web Application Firewalls along with their pros and cons.

  1. Network-based WAF – It’s a locally-installed, hardware-based firewall. It minimizes latency because it’s available locally. However, it’s a big-budget option since one needs to store and maintain the physical equipment.
  2. Host-based WAF – It’s integrated directly into the web application, thus it’s more affordable and customizable than a network-based firewall. But it asks for the application’s server resources and maintenance costs too.
  3. Cloud-based WAF – It’s a cheaper, low-maintenance firewall which works directly from its provider’s infrastructure. It’s auto-updated to protect against the latest security threats and requires minimal upfront cost and maintenance. However, it’s completely maintained by the third party.

Working of a Web Application Firewall

Now, it’s time to understand the functioning of a Web Application Firewall. You must know how it monitors and protects your web applications to perceive its importance in safeguarding your applications from probable attacks. It becomes more important if your application directly communicates via the Internet.

A Web Application Firewall intercepts all incoming web requests and analyzes each of them prior to they reach the web application. It monitors the requests while applying preset rules to identify and act against illegitimate traffic.

A WAF may take different actions depending on its preconfigured options. For example, it can block the incoming traffic, challenge the visitor (user) using a CAPTCHA, or mitigate or simulate an attack on the server. These features stop any illegitimate or malicious traffic from reaching your application server.

Features of a Web Application Firewall

Now, let’s understand and visualize the common features in a Web Application Firewall. You’ll get most of these features in WAFs from well-known and trusted security solution providers. Of course, a WAF can offer more features too.

  1. Monitors attacks – It monitors the traffic, detects attacks, and mitigates them after validating them to minimize false positives. It uses dynamic profiling and attack validation techniques and analyzes different attacks or policy violations to improve accuracy and block bad traffic.
  2. Reports everything – A WAF provides formatted, graphical reports to help you quickly understand the security status and other relevant updates. It creates customizable, template-based reports for assessing the systems or demonstrating the security status for compliance standards.
  3. Integrates SIEMs – A Web Application Firewall usually integrates with popular Security Information and Event Management (SIEM) solutions like LogRhythm, QRadar, etc. It generates events and exports them to various standardized formats like CEF and JSON for further integration.

Why a Web Application Firewall is Important?

In order to decipher the importance of Web Application Firewalls, you must understand their advantages over the traditional security solutions including conventional firewalls, Intruder Detection Systems (IDS), Intrusion Prevention Systems (IPS), etc. So, how do these tools compare against one another?

The traditional security solutions are effective at blocking illegitimate traffic and securing the whole network against intruders. However, they don’t feature the ability to monitor and stop advanced cyber-attacks such as cross-site scripting, session hijacking, etc. and attacks viable using application vulnerabilities.

On the other hand, Web Application Firewalls analyze the incoming web traffic and detect attacks or threats before they reach the application. They block any malicious traffic hidden inside safe-looking traffic, which usually slips from the traditional security systems. Hence, WAFs are crucial for every organization.

So, How to Choose a Web Application Firewall?

A Web Application Firewall is a sophisticated system that plays an important role in your organization’s infrastructure to protect the applications and the customers’ data. That’s why you must opt one from a reputed and trusted service provider, or there is a high probability of an attack on the applications.

Moreover, you must choose a WAF per your company’s business requirements including but not limited to budget, in-house competencies and resources, and scalability requirements. You can pick one of the open-source or proprietary solutions among network-based, host-based, or cloud-based WAFs.

For instance, cloud-based Web Application Firewall offers a competitive yet budget-friendly and customizable solution for protecting your applications against a multitude of attack vectors. It comes in two versions: on-cloud and on-premise, from which you can choose anyone per your requirements.

You can deploy WAF from Imperva the way you want — on-premises in Amazon Web Services and Microsoft Azure or as a cloud service. It promises to protect against most web application risks including the threats listed in OWASP Top 10 and Automated Top 20 like cross-site scripting, remote file inclusion, etc.

Moreover, FlexProtect plans from Imperva offers you multiple tools in flexible and predictable packages for protecting your applications, data, or applications and data. They include Web Application Firewall, IP Reputation Intelligence, DDoS Protection for Websites, and more security tools in neat packages.