Web Application Firewall (WAF) is a critical security feature in Azure that provides centralized protection for web applications against common exploits, vulnerabilities, and attacks. It operates at the application layer (Layer 7) of the OSI model and is designed to inspect HTTP/HTTPS traffic flowi…Web Application Firewall (WAF) is a critical security feature in Azure that provides centralized protection for web applications against common exploits, vulnerabilities, and attacks. It operates at the application layer (Layer 7) of the OSI model and is designed to inspect HTTP/HTTPS traffic flowing to your web applications.
Azure WAF can be deployed with Azure Application Gateway, Azure Front Door, and Azure Content Delivery Network (CDN). It protects applications from threats identified in the OWASP (Open Web Application Security Project) Top 10 vulnerabilities, including SQL injection, cross-site scripting (XSS), and other common attack vectors.
Key features of Azure WAF include:
**Managed Rule Sets**: Azure provides pre-configured rule sets based on OWASP Core Rule Set (CRS) that automatically protect against known vulnerabilities. These rules are regularly updated by Microsoft to address emerging threats.
**Custom Rules**: Administrators can create custom rules to address specific security requirements, allowing filtering based on IP addresses, geographic locations, request headers, and other parameters.
**Modes of Operation**: WAF operates in two modes - Detection mode (monitors and logs threats) and Prevention mode (blocks malicious requests while logging them).
**Bot Protection**: Azure WAF includes bot mitigation capabilities to identify and manage bot traffic, distinguishing between legitimate bots and malicious ones.
**Integration with Azure Monitor**: WAF logs can be sent to Azure Monitor, Log Analytics, Event Hubs, or Storage Accounts for analysis, alerting, and compliance reporting.
**Global and Regional Deployment**: When deployed with Azure Front Door, WAF provides global edge protection, while Application Gateway WAF offers regional protection.
Azure WAF is essential for organizations seeking to meet compliance requirements and protect their web applications from sophisticated cyber threats while maintaining application availability and performance.
Web Application Firewall (WAF) - Complete Guide for AZ-500
Why Web Application Firewall is Important
Web Application Firewall (WAF) is a critical security component that protects web applications from common exploits and vulnerabilities. In today's threat landscape, web applications are primary targets for attackers seeking to steal data, disrupt services, or gain unauthorized access. WAF provides centralized protection against threats like SQL injection, cross-site scripting (XSS), and other OWASP Top 10 vulnerabilities, making it essential knowledge for Azure Security Engineers.
What is Web Application Firewall?
Azure WAF is a cloud-native web application firewall service that provides centralized protection for web applications. It can be deployed with:
• Azure Application Gateway - Regional deployment for protecting web apps • Azure Front Door - Global deployment for edge protection • Azure CDN - Content delivery network integration
WAF uses rule sets to inspect incoming HTTP/HTTPS traffic and blocks malicious requests before they reach your application.
How Web Application Firewall Works
Core Rule Sets (CRS): WAF uses OWASP Core Rule Sets to detect and block common attacks. Azure supports CRS 3.2, 3.1, 3.0, and 2.2.9. The newer versions provide better detection with fewer false positives.
WAF Modes: • Detection Mode - Monitors and logs threats but does not block them • Prevention Mode - Actively blocks detected threats and logs them
Custom Rules: You can create custom rules based on: • IP addresses or IP ranges • Geographic location (geo-filtering) • HTTP parameters (headers, URI, body) • Request rate limiting
Rule Groups: WAF rules are organized into groups protecting against specific attack types: • SQL Injection • Cross-Site Scripting • Local File Inclusion • Remote Code Execution • Protocol Violations
Key Configuration Options
• Exclusions - Define attributes to exclude from WAF evaluation • Per-site and per-URI policies - Apply different policies to different backends • Bot protection - Managed rule set for detecting malicious bots • Rate limiting - Protect against DDoS and brute force attacks
Exam Tips: Answering Questions on Web Application Firewall
Tip 1: Remember that Prevention mode blocks traffic while Detection mode only logs. Questions often test whether you understand when to use each mode.
Tip 2: Know the deployment options - Application Gateway WAF is regional, while Front Door WAF is global. Choose based on whether protection is needed at the edge or regionally.
Tip 3: For questions about protecting against OWASP Top 10 vulnerabilities, WAF with managed rule sets is typically the correct answer.
Tip 4: When questions mention false positives, think about exclusions and custom rules to fine-tune WAF behavior.
Tip 5: WAF policies can be associated with multiple Application Gateways or Front Door profiles - understand the one-to-many relationship.
Tip 6: For geo-filtering requirements, remember that WAF custom rules support blocking or allowing traffic based on country codes.
Tip 7: Bot protection is a separate managed rule set that must be enabled in addition to the OWASP CRS.
Tip 8: When asked about monitoring WAF, remember that diagnostic logs integrate with Azure Monitor, Log Analytics, and Storage Accounts.
Tip 9: Rate limiting rules in WAF help protect against brute force attacks and application-layer DDoS - distinct from Azure DDoS Protection which handles network-layer attacks.
Tip 10: Always consider WAF when questions mention protecting web applications, APIs, or HTTP/HTTPS endpoints from common web exploits.