Web Application Firewall WAF vs Firewall

Have you ever wondered about the difference between a WAF and a firewall? Both are used to secure computer networks, but they serve different purposes.

A firewall is a network security tool that filters network traffic based on predefined rules, while a Web Application Firewall (WAF) is an application security tool that filters traffic between web applications and their users.

In this article, we’ll explain the difference between a WAF and a firewall and help you determine if your organization needs both for security.

Additionally, we will discuss the importance of understanding the difference between network security and application security.

Comparing Application and Network Firewalls

A WAF protects web applications by focusing on HTTP (Hypertext Transfer Protocol) traffic, which is different from a traditional firewall that separates internal and external network traffic.

A WAF is placed between external users and web applications to monitor all HTTP traffic and prevent malicious requests from reaching users or web applications. WAFs safeguard critical web applications and web servers from zero-day threats and other application-layer intrusions.

As businesses expand their digital initiatives, new web applications and application programming interfaces (APIs) may become more vulnerable to attack. 

A network firewall prevents intrusions by blocking unauthorized access to a secured local area network. Its primary purpose is to divide a secure zone from an insecure zone and regulate communication between the two.

Without it, any computer with a public Internet Protocol (IP) address is vulnerable to intrusion from outside the network.

Why Both Technologies Are Essential

Due to the many potential points of intrusion across a network and a web application, it is typically necessary to use both technologies. NGFWs and WAFs are both considered network functions, but they interact with traffic at different locations.

Think of the NGFW as the entrance to a hotel and the WAF as the key to the room. Network firewalls protect network traffic, while WAFs protect applications. Together, an NGFW and a WAF provide comprehensive coverage.

A network firewall can help prevent an attack at the network’s edge by blocking incoming malicious traffic, which can be useful for an application.

The WAF will prevent specific layer 7 attacks against the application, such as attempts to exploit vulnerable software libraries or code-level vulnerabilities like deserialization or injection attacks, as well as DDoS attacks that target the application’s compute resources.

Protection at Layer 7 Instead of Layers 3 and 4

The main technical difference between application-level and network-level firewalls is the security layer they operate on. The Open Systems Interconnection (OSI) model standardizes communication functions within telecommunication and computing systems.

Open Systems Interconnection (OSI) model

WAFs protect against intrusions at Layer 7 of the OSI model, which is the application level. This includes cookie manipulation, SQL injection, and URL attacks, as well as attacks against applications like Ajax, ActiveX, and JavaScript.

Additionally, they target the web application protocols HTTP and HTTPS, which connect web browsers and web servers.

For example, a Layer 7 DDoS attack sends a flood of traffic to the server layer, where web pages are generated and delivered in response to HTTP requests.

A WAF mitigates this by functioning as a reverse proxy to protect the targeted server from malicious traffic and filter requests to identify DDoS tools.

Layers 3 and 4 of the OSI model are used by network firewalls to protect data transfer and network traffic. This includes Domain Name System (DNS) and File Transfer Protocol (FTP) attacks, as well as Simple Mail Transfer Protocol (SMTP), Secure Shell (SSH), and Telnet attacks. 

Web Attacks Compared to Unauthorized Access

Protection against web-based attacks is provided by WAF solutions. Without an application firewall, intruders could penetrate the LAN.

WAFs defend against web-based assaults, such as overwhelming a network or server with internet traffic, which depletes the target’s resources and cannot be detected.

SQL injection allows hackers to take control of a web application’s database server. Without authentication, attackers can retrieve the SQL database’s content and add, modify, or delete records, thus gaining access to customer and intellectual property information. It was one of the top 10 OWASP threats in 2017.

Cross-site scripting enables hackers to compromise interactions between users and applications, bypassing the policy that separates websites based on their origin. To gain access to data and resources, the intruder must assume the identity of a valid user.

Firewalls prevent unauthorized network access and traffic and protect against network-wide intrusions on connected devices and systems.

A list of common network attacks includes:

  • Unauthorized Network Access
  • Theft of Credentials
  • WAF Passwords
  • Insider Threats

A Web Application Firewall serves the following purposes:

  1. Firewalls are generally used to monitor network traffic, providing an additional layer of security by scanning all site traffic and securing the network against malicious malware and multiple attack vectors.
  2. Unlike firewalls, WAFs not only passively monitor activity but also proactively shore up weaknesses in web applications. They constantly scan for vulnerabilities and frequently observe network vulnerabilities, repairing them before the user is aware.
  3. Although a patch is not a permanent solution, it gives the user time to solve the problem and prevents potential network breaches.

Web Application Firewall (WAF) Benefits

  1. Preventing customer data from being compromised by ensuring that customer data is not exposed to potential vulnerabilities and malicious attacks.
  2. Enforcing compliance – WAFs ensure that data is rigorously organized in accordance with HIPAA and PCI standards, blocking any opportunities or vulnerabilities that could provide hackers with a space to conduct attacks.
  3. Saving the user a substantial amount of resources by automatically performing security tests and monitoring traffic.
  4. Preventing assaults – WAFs prevent various attacks, such as SQL injections, cross-site scripting (XSS) attacks, and distributed denial of service (DDoS) attacks, by conducting effective monitoring, running security tests, and creating patches for weak points.

Who is Using WAFs vs. NGFWs?

The coordination of diverse technologies raises the issue of manageability and the question of who the stakeholders are.

A WAF is typically of greater interest to anyone serving the application, including developers who are not security experts. Meanwhile, IT is primarily concerned with the network firewall.

Building and adjusting effective WAF policies requires comprehensive knowledge of the application, and the author of the code is typically a useful resource for determining how to protect it. They are ideally positioned to create a WAF policy that addresses the app’s vulnerabilities, as they are aware of its strengths and limitations.

A WAF is still infrastructure, so its deployment is typically the responsibility of IT security. However, it is an excellent addition to a DevSecOps program in which security is thoroughly integrated into the development process. Therefore, cooperation between developers and IT is essential.

It is beneficial to involve developers in the WAF configuration process, as they need to test the technology to have trust in it.

Both NGFWs (Next-Generation Firewalls) and WAFs (Web Application Firewalls) face the potential threat of false positives.

Unlike NGFWs, WAFs can be tested within CI/CD (Continuous Integration/Continuous Deployment) pipelines during or after the development of applications. A WAF displays the appearance, payload, and functionality of the app, enabling you to verify that everything is matching and working properly.

All in all  

In conclusion, although both firewalls and WAFs play a crucial role in maintaining network and application security, they serve different purposes.

WAFs provide security to web applications and their users by filtering traffic between them, while firewalls provide network security by filtering traffic based on predefined rules.

Firewall: Network security tool. Filters network traffic based on predefined rules.

WAF: Application security tool. Filters traffic between web apps and users.

The need for both depends on the specific security requirements and desired level of security for an organization. It’s crucial to understand the difference between network security and application security, as well as the associated risks, to make informed decisions about which security tools to implement in the organization.

Explore the various firewall security capabilities offered by Cloudflare and the web application firewall provided by Sucuri Website Security.

Related articles:

Cloud Security: Challenges & Effective Solutions

Endpoint Security: Protect Your Workstations with Confidence

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