What Is a WAF?
What Is a WAF?
A Web Application Firewall (WAF) is a security solution designed to protect web applications and APIs by monitoring, filtering, and blocking malicious HTTP/HTTPS traffic before it reaches the origin server.
Unlike traditional network firewalls that operate at the network or transport layer (L3/L4), a WAF works at the application layer (Layer 7) and understands web-specific protocols, requests, and behaviors.
In short: 👉 WAF sits in front of your web application and acts as a security gatekeeper.
Why Do You Need a WAF?
Modern web applications are exposed to many threats such as:
SQL Injection (SQLi)
Cross-Site Scripting (XSS)
Remote Code Execution (RCE)
File Inclusion (LFI/RFI)
Bot abuse, scraping, and credential stuffing
DDoS attacks at the application layer
A WAF helps you:
Protect applications without changing source code
Reduce security risks and data breaches
Meet compliance requirements (e.g. PCI-DSS, security regulations)
Improve overall application availability and reliability
How a WAF Works
Typical traffic flow:
1. A client sends an HTTP/HTTPS request
2. The WAF inspects the request in real time
3. Security rules and detection engines analyze the request
4. Based on the result, the WAF:
Allows the request
Blocks the request
Challenges the request (CAPTCHA, verification)
Logs the request for monitoring and auditing
Key Capabilities of a WAF
1. Attack Protection
OWASP Top 10 protection
Zero-day and unknown attack pattern detection (behavior-based)
Protocol and request validation
2. Access Control
IP allowlist / denylist
Geo-based access control
Rate limiting by IP, URL, or user behavior
3. Bot Management
Detect and mitigate malicious bots
Allow legitimate bots (search engines, monitoring tools)
Protect login pages and APIs from brute-force attacks
4. Traffic Visibility & Logging
Real-time request and attack logs
Detailed attack details (rule, source IP, payload, action)
Traffic statistics and trends
5 Custom Rules
Create allow, deny, or monitoring rules
Match by URL, method, headers, parameters, body
Flexible rule priority and scope
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