AWS Web Application Firewall

AWS Web Application Firewall (WAF) is a fully managed service by AWS that protects your web applications from bad traffic and malicious threats. It integrates with many AWS services including Amazon CloudFront, Application Load Balancer (ALB), API Gateway and AWS App Runner.

AWS WAF works by allowing you to create security rules that inspect incoming HTTP(S) requests. These rules can detect and block bad traffic so only good requests get to your application. The firewall evaluates each request based on the criteria you set, such as the request’s IP address, geographic location, query strings and HTTP headers. If a request matches any of your rules, AWS WAF takes the action you specified – block, allow or count the request.

In this article we will go through the features of AWS WAF and walk you through the setup to protect your web applications.

What is AWS Web Application Firewall (WAF)

AWS WAF is a robust security tool designed to protect your web applications from harmful traffic and common vulnerabilities. It allows you to create customizable security rules that evaluate incoming HTTP(S) requests, block bad traffic, and allow legitimate requests. By filtering web traffic, AWS WAF ensures that only authorized users can access your resources.

With AWS WAF, you can:

• Protect against common web vulnerabilities like SQL injection and XSS.
• Set customizable security rules based on IP addresses, headers, query strings, and more.
• Integrate with other AWS services for a seamless security experience.

Getting Started with AWS WAF

AWS WAF continuously monitors all incoming and outgoing web requests that pass through services such as API Gateway, Amazon CloudFront, and Application Load Balancer (ALB) to help protect your web applications from malicious traffic.

Step 1: Create web ACL

Firstly signing up for an AWS account if you haven’t already. Next, go to the AWS Console and search for "Web Application Firewall." This will take you to the AWS WAF home page, where you can select the option to create a new Web ACL

Before Going to next step, refer to the article - Identity and Access Management (IAM) in AWS

Step 2: Give a Name

Enter a name to identify your Web ACL. You can also add an optional description if desired. Once done, click "Next" to proceed

Step 3: Add an AWS Managed Rule Group

In this step, you’ll need to add rules and rule groups. Select "Add managed rule groups", which will take you to a page where you can manage the rule groups, as shown in the reference snapshot

AWS Managed Rules offers a selection of predefined rule groups, most of which are free for AWS WAF users. Once you’ve added a managed rule group, save the configuration.

In this setup, we’ll create two specific rules to define the traffic patterns we want to allow or block:

• Regular Rule: This rule protects the application against SQL injection attacks by checking if the URI path contains any SQL injection patterns.
• Rate-Based Rule: This rule blocks requests from the same IP address once they exceed a specified request limit within a given time frame.

After that, check the added rules and hit Next

Step 4: Configure Cloudwatch Metrics

Step 5: Review Web ACL Configuration

In the final step, review all selected rules and managed rule groups to ensure they meet your requirements. Once confirmed, click "Create Web ACL" to complete the setup

A confirmation message will appear saying, "You have successfully created Web ACL: [ACL-name]".

Key Features of AWS WAF

AWS WAF comes with several features that make it a reliable and scalable solution for web application security:

1. Customizable Rules

AWS WAF allows you to create custom security rules tailored to your application’s specific needs. You can set conditions based on various factors, such as IP addresses, HTTP headers, or geographical location. This customization helps ensure that only legitimate traffic reaches your application, while harmful requests are blocked.

2. Managed Rule Groups

For a faster setup, AWS WAF provides pre-configured managed rule groups that protect against common threats like SQL injection, cross-site scripting (XSS), and malicious IP addresses. These rules are regularly updated to stay ahead of emerging security risks, making it easy for you to get started with minimal configuration.

3. Real-Time Monitoring and Logging

AWS WAF provides real-time monitoring and logging of web traffic. With AWS WAF Logs, you can track detailed information about each request, including which rules were triggered and what actions were taken. This visibility helps you analyze traffic patterns, troubleshoot issues, and fine-tune your security settings over time.

4. DDoS Protection

AWS WAF integrates with AWS Shield, offering automatic protection against Distributed Denial of Service (DDoS) attacks. This integration ensures your application remains available and responsive, even during large-scale attack attempts.

5. Cost-Effective and Scalable

AWS WAF operates on a pay-as-you-go pricing model, meaning you only pay for the rules you create and the volume of web requests your application receives. As your application grows, AWS WAF scales automatically to handle increased traffic, ensuring continued protection without added complexity.

Benefits of AWS WAF

• Comprehensive Security: AWS WAF provides strong protection against common web threats such as SQL injection and cross-site scripting (XSS), ensuring your application remains secure from these types of attacks.
• Customizable Rules: You have the flexibility to create security rules tailored to your specific requirements, enabling you to filter traffic based on IP addresses, headers, or other criteria.
• Pre-Configured Managed Rules: AWS offers a collection of pre-built rules that are frequently updated to guard against known vulnerabilities, so you don’t need to worry about manual updates.
• Scalable: As your traffic increases, AWS WAF effortlessly scales to accommodate the higher volume, making it an excellent choice for businesses of all sizes.
• Cost-Effective: With a pay-as-you-go pricing structure, you only pay for what you use, making it a budget-friendly option for businesses at different growth stages.
• Real-Time Insights: AWS WAF integrates with CloudWatch, providing you with detailed logs and analytics. This feature allows you to monitor and respond to security threats as they happen.
• DDoS Protection: AWS WAF collaborates with AWS Shield to automatically protect against DDoS attacks, adding an extra layer of security.
• Seamless Integration with AWS: It works smoothly with other AWS services like CloudFront, Elastic Load Balancing (ELB), and API Gateway, simplifying deployment and enhancing efficiency.

Limitations of AWS WAF

• Complex Setup: Setting up custom rules and navigating the security options can be challenging, particularly for users who aren't familiar with AWS or web security.
• Focus on Layer 7: AWS WAF is primarily designed to protect at the application layer (Layer 7). It doesn't offer deep protection at lower network layers, so it may not address all types of network-level attacks.
• Ongoing Management: Custom rules require regular updates to stay effective, which means continuous attention and effort from your team.
• Can Get Expensive: For applications with high traffic, the pay-as-you-go pricing model can lead to escalating costs as your traffic increases.
• Learning Curve: New users may find the AWS Console and setup process overwhelming if they aren't already familiar with the platform.
• Limited Flexibility with Managed Rules: While AWS offers managed rules, your control over fine-tuning them to your specific needs is somewhat limited.
• Potential Latency: A large number of rules or managing high traffic volumes can introduce slight delays in processing requests, potentially affecting performance.
• AWS-Specific: AWS WAF is designed primarily for use with AWS services, making it less ideal for protecting infrastructure that isn't hosted on AWS.

AWS WAF Pricing Breakdown

AWS WAF operates on a pay-as-you-go pricing model, making it cost-effective for businesses of all sizes. The main factors influencing the pricing are:

1. Web ACL
   AWS charges $5 per month for each Web Access Control List (Web ACL) you create.
2. Rules
   You will be charged $1 per month for each rule you configure for your Web ACL.
3. Requests
   AWS WAF charges $0.60 per million requests processed.
4. Managed Rule Groups
   Managed rules come with additional costs. You pay based on the number of rules and the traffic volume. These costs vary depending on the selected rule group.

AWS WAF Cost Example:

• Web ACL: $5 per month
• Rules: $1 per month per rule
• Requests: $0.60 per million requests
• Managed Rules: Varies based on usage

Conclusion

AWS Web Application Firewall (WAF) plays an important role in protecting modern web applications from a variety of evolving security threats. It enables users to create flexible and customizable security rules, offering robust defense against common vulnerabilities like SQL injection and cross-site scripting. AWS WAF works seamlessly with other AWS services, providing a cost-effective and straightforward solution suitable for businesses of all sizes, from startups to large enterprises. By utilizing AWS WAF, organizations can take proactive measures to safeguard their applications, ensuring a secure and high-quality experience for users while reducing security risks. Implementing AWS WAF not only enhances security but also fosters trust with customers by safeguarding their sensitive information.