# web application firewall

> HTTP specific network security system

**Wikidata**: [Q25348457](https://www.wikidata.org/wiki/Q25348457)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Web_application_firewall)  
**Source**: https://4ort.xyz/entity/web-application-firewall

## Summary
A web application firewall (WAF) is an HTTP-specific network security system that monitors, filters, and blocks HTTP traffic to and from a web application. It operates as a specialized form of application firewall designed to protect web applications from common attacks like SQL injection, cross-site scripting, and other web exploits.

## Key Facts
- A web application firewall is a subclass of application firewall, which controls input/output or system calls of an application or service
- The term "WAF" has multiple aliases including Web应用防护系统, Web应用程序防火墙, and 网页应用防火墙
- The Wikipedia page for web application firewall exists in 9 languages: de, en, es, fa, fr, ja, ko, lmo, pt, ru
- The entity has a Google Knowledge Graph ID of /g/11c0p_6z6s
- Related commercial WAF services include AWS WAF (offered by Amazon Web Services) and Google Cloud Armor (offered by Google's Cloud Platform)
- The Wikidata description identifies it as an "HTTP specific network security system"
- The entity has 12 sitelink counts across Wikimedia projects

## FAQs

### Q: What is the difference between a web application firewall and a traditional firewall?
A: A traditional firewall operates at the network or transport layer and filters traffic based on IP addresses, ports, and protocols. A web application firewall operates at the application layer specifically for HTTP/HTTPS traffic and understands web application logic to protect against application-specific attacks.

### Q: What types of attacks does a web application firewall protect against?
A: A web application firewall protects against common web application attacks including SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF), file inclusion, and application-layer DDoS attacks.

### Q: Where is a web application firewall typically deployed?
A: A web application firewall can be deployed as a network appliance, a server plugin, or a cloud service. It's typically positioned in front of web servers to intercept and inspect all HTTP/HTTPS traffic before it reaches the application.

## Why It Matters
Web application firewalls are critical security infrastructure in today's internet landscape where web applications face constant threats from sophisticated attackers. As web applications have become the primary interface for businesses to interact with customers, they've also become prime targets for cybercriminals seeking to steal data, disrupt services, or compromise systems. WAFs provide a vital layer of protection by understanding the specific patterns and behaviors of web applications, allowing them to detect and block attacks that traditional network firewalls would miss. They're particularly important for compliance with security standards like PCI DSS and for protecting against zero-day vulnerabilities in web applications. Without WAFs, organizations would be far more vulnerable to data breaches, service disruptions, and the financial and reputational damage that follows.

## Notable For
- Specialized protection for HTTP/HTTPS traffic at the application layer
- Understanding of web application logic and common attack patterns
- Ability to protect against both known vulnerabilities and zero-day exploits
- Integration with cloud services and content delivery networks
- Support for compliance requirements in regulated industries

## Body
### Technical Architecture
Web application firewalls operate at the application layer (Layer 7 of the OSI model) and inspect HTTP/HTTPS traffic in both directions. They use various detection methods including signature-based detection, behavioral analysis, and machine learning to identify malicious requests.

### Deployment Models
WAFs can be deployed in multiple configurations: as on-premises hardware appliances, as software installed on servers, as virtual appliances in cloud environments, or as fully managed cloud services. Cloud-based WAFs are increasingly popular due to their scalability and ease of deployment.

### Protection Mechanisms
The core functionality of a WAF includes request filtering based on rulesets, traffic monitoring and logging, rate limiting to prevent DDoS attacks, and virtual patching to protect against vulnerabilities until they can be properly fixed in the application code.

### Integration with Security Ecosystem
Modern WAFs often integrate with other security tools including intrusion prevention systems (IPS), security information and event management (SIEM) systems, and web application and API protection (WAAP) platforms to provide comprehensive security coverage.

### Industry Standards and Compliance
WAFs play a crucial role in meeting compliance requirements for standards like PCI DSS, HIPAA, and GDPR. Many regulatory frameworks specifically require application-layer protection for web-facing systems that handle sensitive data.