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A media company hosts a public-facing web application in Azure. The application is a common target for various web-based attacks, including SQL injection, cross-site scripting (XSS), and DDoS attacks. The company needs a solution to protect the application from these common web vulnerabilities and to filter malicious traffic before it reaches the backend servers. Which Azure networking service should be implemented?

  1. AAzure Web Application Firewall (WAF)
  2. BAzure DDoS Protection Standard
  3. CAzure Firewall
  4. DAzure Network Security Group (NSG)
Show answer & explanation

Correct answer: A. Azure Web Application Firewall (WAF)

Azure Web Application Firewall (WAF) provides centralized protection of web applications from common exploits and vulnerabilities such as SQL injection and cross-site scripting. It operates at Layer 7 (application layer) and can be deployed with Azure Application Gateway or Azure Front Door, making it ideal for public-facing web apps.

Why the other options are wrong

  • B. Azure DDoS Protection Standard protects against volumetric and protocol-based DDoS attacks but does not mitigate application-layer web vulnerabilities.
  • C. Azure Firewall is a managed cloud-based network security service that protects Azure Virtual Network resources but does not offer specific application-layer web attack protection like WAF.
  • D. NSGs operate at Layer 4 (transport layer) and Layer 3 (network layer), providing basic traffic filtering, but cannot protect against application-layer attacks like SQL injection or XSS.

Azure Web Application Firewall (WAF)

A feature of Azure Application Gateway and Azure Front Door that provides centralized protection of web applications from common exploits and vulnerabilities, such as SQL injection, cross-site scripting, and other OWASP Top 10 risks.

  • Protects against common web vulnerabilities (OWASP Top 10)
  • Operates at Layer 7 (Application Layer)
  • Can be deployed with Application Gateway or Front Door
  • Provides real-time threat intelligence

Memory trick: For web attacks, 'WAF' is the 'W'all 'A'gainst 'F'aults.

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