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In this blog, we will be discussing what the WAF is, its role, and its necessity in any network environment.

A WAF or web application firewall helps protect web applications by filtering and monitoring HTTP traffic between a web application and the Internet. It typically protects web applications from attacks such as cross-site forgery, cross-site-scripting (XSS), file inclusion, and SQL injection, among others. A WAF is a protocol layer 7 defense (in the OSI model) and is not designed to defend against all types of attacks. This method of attack mitigation is usually part of a suite of tools that together create a holistic defense against a range of attack vectors.

Apart from the theoretical definition, we also should have knowledge about the placement of WAF and how it works in the production environment. The WAF is deployed in front of a web application and it acts as a barrier between a web application and the Internet. A WAF is a type of reverse proxy that protects the server from exposure by having clients pass through the WAF before reaching the server.

A WAF operates using a set of rules known as policies. By filtering out harmful traffic, these policies endeavor to protect against application vulnerabilities. working as an Application Security Engineer in DNS, I also have great experience in deploying and providing support for WAF at various institutions. It’s really interesting working on it. While deploying WAF we must understand network design and architecture for networks and should have knowledge of a firewall, DNS, VPN, Routing, Load balancing, and many more.

WAF protects servers from web application attacks like SQL Injections, XSS, parameter tampering, and many other attacks. So, it works on reverse proxy architecture to protect backend servers from those attacks. Now let’s discuss different types of proxies.

Reverse Proxy

Proxies generally protect clients, whereas WAFs protect servers. WAFs are deployed to protect a specific web application. Therefore, a WAF can be considered a reverse proxy. WAFs may come in the form of an appliance, server plug-in, or filter, and may be customized to an application.

Forward Proxy

A forward proxy is the most common form of a proxy server and is generally used to pass requests from an isolated, private network to the Internet through a firewall. Using a forward proxy, requests from an isolated network, or intranet, can be rejected or allowed to pass through a firewall.

Half Proxy

Half-proxy is a description of the way in which a proxy, reverse or forward, handles connections. There are two uses of the term half-proxy: one describing a deployment configuration that affects the way connections are handled and one that describes simply the difference between a first and subsequent connections.

Full Proxy

A full proxy maintains two separate connections. One between proxy and the client and the other between proxy and the destination server. The full proxy can look at incoming requests and outbound responses and can manipulate both if the solution allows it. Many reverse and forward proxies use a full proxy model today. A full proxy completely understands the protocol and itself acts as an endpoint and an originator for the protocols.

Difference between a web application firewall (WAF), an intrusion prevention system (IPS), and a next-generation firewall (NGFW)

There are several reasons that contribute to the misconception regarding NGFWs and WAFs. As both systems are referred to as firewalls, some individuals may mistake them for one another. The phrases are sometimes used interchangeably because NGFWs are advancements of traditional network firewalls. While both systems are designed to detect and prevent malicious intrusions, they each provide a different level of protection.

The challenge of manageability arises when several technologies are combined. Even if they aren’t security professionals, everybody serving the application including developers will be interested in a WAF. Meanwhile, IT is more concerned with the network firewall.

Building and fine-tuning efficient WAF policies necessitate a deep understanding of the application. And the person who created the code is generally a useful resource for figuring out how to safeguard it. They are in the best position to create a WAF strategy that tackles the application’s vulnerabilities because they are familiar with its strengths and shortcomings. Because a WAF is still infrastructure, it’s usually deployed by IT security; nonetheless, it’s an excellent tool to incorporate in a DevSecOps program, where security is thoroughly integrated into the development process.

Now taking about IPS, an intrusion prevention system (IPS) is a security tool with a broader scope. It is usually a signature and policy-based firewall, which means it can scan for known vulnerabilities and attack vectors using a signature database and policies. The IPS creates a standard based on the database and policies, and then sends out alarms when traffic differs from it. As new vulnerabilities are discovered, the signatures and regulations are updated. IPS protects traffic across a range of protocols including DNS, SMTP, TELNET, RDP, SSH, and FTP.

It’s not easy to secure your networks and applications; it’s not supposed to be. Hackers have the ability to gather in-depth knowledge of a system and its flaws and then exploit that information. To stay ahead of hackers, businesses must be smarter than hackers,

which involves working on behalf of the key stakeholders to implement effective NGFW and WAF controls.

WAF-Layer 7 protection

Web Application Firewall (WAF) helps to protect API applications and web applications from malicious attempts by attackers. It protects Web Applications and API Endpoints from a variety of attacks, such as SQL Injection, LFI, Cross-Site-Scripting (XSS), and more. Web Application Firewall (WAF) is a part of layer 7 defense, it is designed to examine all HTTP or HTTPs traffic between external users and web applications. It detects and prevents malicious sources from gaining access to users or web applications. This is becoming increasingly important as businesses embark on new digital initiatives, exposing new Web applications and APIs to attack. Without proper configuration and cyber security solutions, API endpoints would be exposed to many cyber security vulnerabilities. Businesses must understand their security threats and defenses in the age of sophisticated cyberattacks and digital innovation. This applies particularly to firewalls that protect API endpoints and web applications from different attacks.

The only countermeasures for securing layers 6 and 7 are secure programming or WAF. However, the defenses in secure programming have their limits. For example, no matter how hard we try to secure programming, vulnerabilities in middleware and programming languages are discovered every day. The task of securely rewriting and continually updating the program each time can be quite daunting. If a vulnerability is discovered with a WAF, we can simply update your signature and not make any program changes. To safely, easily, and reliably protect the seven layers of the OSI reference model, WAF is the way to go. Also, it is very easy to attack the application layer. A SQL injection attack is possible with application knowledge, and an attack is also possible if the vulnerability is disclosed. Because it is easy to become a target of the attack, it is necessary to protect applications with products such as WAF to prevent them from being destroyed, tampered with, or accessed illegally.


So, we have discussed WAF and compared it with the next-generation Firewall and IPS. Moreover, a Web Application Firewall (WAF) filters out malicious requests to a web application or API. It also provides more visibility as to where the traffic is coming from. Also, the Web Application Firewall (WAF) is a part of the layer 7 defense. It is designed to examine all HTTP or HTTPS traffic between external users and web applications and also helps to gain application availability by providing security against Layer 7 attacks.


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