WAF (Web Application Firewall) vs. Firewall: Explained

What are the advantages of WAF (Web Application Firewall) compared to traditional firewalls? What is WAF in terms of website security, and why is it indispensable? Have WAF rule settings made it easier for website administrators? These are the essential WAF insights that corporate cybersecurity personnel must be familiar with!

WAF (Web Application Firewall) vs. Firewall: The Differences

WAF stands for Web Application Firewall, which provides protection for website service. The main difference between WAF and conventional Firewall lies in the level of data layer used for signature recognition.

Conventional Firewall primarily identifies threats based on the packet transmission location (IP address) and port number of the application program. These pieces of information belong to Layer 3 (Network layer) and Layer 4 (Transport layer) of the OSI model. Therefore, conventional Firewall is often referred to as L4 Firewall, as it operates at most up to Layer 4 and cannot recognize the application contents within the transmitted data at Layer 7.

WAF, on the other hand, focuses on protecting the Web application services at Layer 7 of the OSI 7 layer model. This means that WAF can identify the Web application contents contained within the transmitted data.

WAF (Web Application Firewall) can identify HTTP contents

How do WAF and conventional Firewall handle L7 Attacks?

The following example of a malicious crawler is used to describe the advantages of WAF (Web Application Firewall) over conventional Firewall.

Limitations of L4 Firewall in Blocking Malicious Crawlers

The conventional firewall can only block malicious requests based on the source IP or port number, which means it can only identify “where the request comes from, where it is going, and what it is looking for,” without recognizing the HTTP headers related to web crawlers within the transmitted data. Therefore, the web administrator must analyze the content of the crawler to determine the appropriate blocking, allowing, or bandwidth restriction strategies based on the source location. If the attack originates from multiple locations and the source keeps changing, the administrator needs to constantly update the blocking list to effectively block the attack. Otherwise, blocking an entire region directly may unintentionally block legitimate users from the same region.

WAF Filters and Blocks HTTP Traffic, Intercepting Crawler Behaviors

WAF (Web Application Firewall) can recognize the HTTP headers encapsulated within the transmitted data, allowing web administrators to block specific crawler behaviors based on not only source IP but also the information found in the User-Agent field of the HTTP header, such as Baiduspider, Googlebot, Bingbot, and others.

WAF（Web Application Firewall）can identify User-Agent and block malicious crawlers

In addition, because WAF primarily deals with HTTP service contents, in order to block malicious requests, some WAF services offer additional application layer verification mechanisms during the access process, in addition to the common blocking and permitting functionalities. Advanced WAF services include features like redirection and customized HTTP responses. Beyond defense, WAF functions have a wider range of applications based on the specific needs of different websites. Unlike most conventional firewalls that only offer blocking or permitting capabilities, WAF is better equipped to handle the ever-evolving landscape of network attacks, making it suitable for meeting the cybersecurity requirements of modern websites.

ApeiroCDN's WAF is sophisticated and comprehensive. Requests with or without the specific signatures can all be targeted and dealt with dozens of response actions. — ApeiroCDN’s WAF (Web Application Firewall) is feature-rich, specifically designed to handle complex L7 attacks.

ApeiroCDN’s WAF Tackles Complex L7 Attacks

Supports Regular Expressions, Allowing Flexible Usage

ApeiroCDN’s WAF services offer diverse WAF rule configurations, allowing for multiple action choices based on specified conditions. This enables a more flexible defensive strategy, accurately distinguishing and blocking malicious traffic without impacting regular users. Additionally, the convenience of WAF configuration lies in its support for regular expression in both header and parameter settings, providing website administrators with greater flexibility in blocking malicious requests.

ApeiroCDN's WAF (Web Application Firewall) rule settings on the management platform uses Regular expression to block multiple crawlers. — ApeiroCDN’s WAF (Web Application Firewall) rule settings on the management platform uses Regular expression to block multiple crawlers.

On the ApeiroCDN management platform, WAF (Web Application Firewall) rule settings use regular expression to block outdated browser versions.

ApeiroCDN’s WAF: Diverse Actions for Precise Blocking

The ApeiroCDN management platform offers a wide range of 13 different actions for configuring WAF rules. In addition to common actions such as deny, allow, robot verification, and webpage redirection, it also provides features like speed limiting, block period (penalty time), custom response pages, and custom headers. Users can choose the desired actions based on the current situation. For example, when facing an attack and unable to block arbitrarily without identifying specific signatures, but still needing to reduce the server’s workload, request frequency can be combined with block period or speed limiting to mitigate instead of outright blocking.

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Example: If a specific crawler exceeds 200 requests per second, it will be temporarily blocked for 300 seconds. If no further occurrences are detected within this period, access will be automatically restored.

ApeiroCDN's WAF rules can limit behavior based on the "request rate" before identifying specific attack signatures. — ApeiroCDN’s WAF rules can limit behavior based on the “request rate” before identifying specific attack signatures.

Configure WAF rules on ApeiroCDN management platform to set "block period" for specific conditions, limiting suspicious request behavior. — Configure WAF rules on ApeiroCDN management platform to set “block period” for specific conditions, limiting suspicious request behavior.

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ApeiroCDN’s User-friendly WAF (Web Application Firewall)

Due to the platform-independent nature of web-based services, where service can be provided as long as the user’s device can access webpages, WAF has become an essential protection system for enterprises offering online services. However, traditional hardware-based WAF systems require higher management and operational efforts compared to conventional firewalls.

To address this, ApeiroCDN provides a user-friendly and comprehensive WAF protection system, allowing administrators to eliminate the costs of system maintenance while enabling flexible configuration to align with their specific defense policies.

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