WAFs protect web applications by inspecting and filtering traffic at the application layer. They complement firewalls, which offer protection at other network layers.
Many WAFs rely on rules to recognize specific attack traffic patterns and drop or log potentially malicious requests. However, this approach can be challenging and prone to false positives.
WAF is a Reverse Proxy
A WAF acts as a reverse proxy for your web application, intercepting requests and analyzing them to determine how they should be handled. It looks for malicious traffic patterns and blocks or allows them based on the policies you deploy. It also analyzes user-agent strings, cookie headers, and other indicators of a malicious attack.
Depending on your needs, a managed WAF can be deployed as a transparent reverse or routing proxy. This means that the web applications it protects are unaware of its presence, and clients are unaware they are passing through a firewall. This approach provides greater transparency than a traditional network firewall, often seen as a barrier between the external network and internal web applications.
WAFs are a vital component of your security infrastructure, protecting your web apps from common threats like SQL injection, cross-site scripting attacks, third-party vulnerability attacks, CC attacks, and more. They work with other security measures, such as IDS and IPS, to provide a complete defense-in-depth security model. WAFs are available as software, appliances, or a hosted cloud service and can be network- or hardware-based.
WAF is a Firewall
The WAF protects web applications from threats like Structured Query Language (SQL) injection, cross-site scripting (XSS), and distributed denial-of-service attacks (DDoS). It also prevents data leakage by monitoring outbound requests and masking or blocking sensitive information. This is important to e-commerce sites and other companies providing services involving customer interactions or business partners.
In WAF vs. firewall difference, WAF can be a cloud-based solution, an appliance, or a server plugin in front of a company’s web applications. It filters data packets to detect common web attacks and suspicious traffic patterns. WAFs can be configured with rules based on policies set by organizations that tell them what types of risky traffic are and how to react when they occur.
Unlike traditional firewalls, which use static rules to determine the legitimacy of network traffic, WAFs analyze and monitor the behavior of web application attacks. They also incorporate context-based security features such as geo-fencing, a technique that creates a virtual boundary around specific geographic locations or IP addresses to allow or block access to specific endpoints or types of traffic.
Early WAFs, known as stateless WAFs, used pattern recognition to evaluate inbound requests and respond according to predetermined models of attack behavior. However, they needed to be more adaptable to ward off evolving attacks. In the end, attackers figured out ways to circumvent WAF defenses and evade detection.
WAF is a Web Application Firewall
A WAF is an application-layer firewall that protects web applications in internet-facing zones against attacks. Unlike traditional network firewalls that inspect data packets per IP, WAF filters and monitors HTTP and HTTPS traffic, inspecting each request for malicious patterns.
As the security industry responds to evolving threats, many WAFs have built-in algorithms that detect patterns in attack traffic and generate policies to prevent these attacks. This saves time and resources for organizations, as they don’t need to create rules for each new type of threat manually.
WAFs analyze each request and response for malicious patterns and anomalies, such as suspicious strings, value pairs, or misconfigured header values. They also look for common attack vectors such as URL redirections, asymmetric GET requests, and malformed cookie values.
A WAF can be deployed on-premises as a hardware-based appliance to reduce latency and be installed as close to the field application as possible. These appliances support large-scale deployment, configuration, and maintenance by allowing administrators to replicate device rules.
Another option is to deploy a cloud-based WAF as a virtual appliance, which requires less setup effort and can be managed remotely by the vendor. However, these solutions often require significant upfront investment and ongoing maintenance costs. Host-based WAFs, meanwhile, are fully integrated into the software of each host server or application container. These offer more control, customization, and customization but can consume substantial local server resources and be complex to implement and maintain.
WAF is a Network Firewall
Traditionally, businesses protected their network firewalls with intrusion detection systems (IDSes) and intrusion prevention systems (IPS). These technologies don’t provide the transparency or flexibility to protect against modern attacks. This has led to the growth of web application firewalls, which use rules and signatures to protect against vulnerabilities, zero-day threats, and impersonation.
WAFs are deployed before web applications and analyze bi-directional HTTP traffic to detect malicious activity. They also protect against data leakage by monitoring and blocking responses that contain sensitive information. They can also ensure adherence to critical legal requirements.
Most offer a variety of security policies that are customizable to the needs of each organization. Some also use artificial intelligence and behavioral baselines to detect new attacks and anomalies that traditional signature-based tools might miss.