AWS Serverless: WAF & Protection

Introduction

Web Application Firewall (WAF) is a crucial security component for protecting web applications from common web exploits that could affect application availability, compromise security, or consume excessive resources. AWS WAF is designed to be used with AWS services like Amazon API Gateway, making it a key asset in serverless architectures.

What is WAF?

AWS WAF is a managed web application firewall that helps protect your web applications from common web exploits. It allows you to create security rules to filter web traffic, based on conditions such as IP addresses, HTTP headers, HTTP body, and URI strings.

Key Features:

• Customizable rules for filtering web traffic.
• Integration with AWS services like API Gateway and CloudFront.
• Real-time visibility into web traffic through metrics and logging.
• Easy to set up and manage through the AWS Management Console.

How WAF Works with API Gateway

When you configure AWS WAF with Amazon API Gateway, it acts as a filter for incoming requests to your APIs. The WAF inspects requests based on the rules you define, allowing or blocking traffic accordingly.

The following flowchart illustrates the request flow between AWS WAF and API Gateway:

graph TD;
    A[Client Request] --> B[API Gateway]
    B --> C{WAF Rules}
    C -->|Allow| D[Forward to Lambda]
    C -->|Block| E[Return Error]
                

Setup and Configuration

To set up AWS WAF with API Gateway, follow these steps:

1. Create a WAF web ACL (Access Control List).
2. Define rules based on your security requirements.
3. Associate the web ACL with your API Gateway.
4. Test the configuration to ensure it is functioning as expected.

Here's an example of creating a WAF Web ACL using AWS CLI:

aws wafv2 create-web-acl \
    --name MyWebACL \
    --scope REGIONAL \
    --default-action '{"Allow": {}}' \
    --description "Web ACL for API Gateway" \
    --visibility-config '{"SampledRequestsEnabled": true, "CloudWatchMetricsEnabled": true, "MetricName": "MyWebACL"}' \
    --region us-east-1
                

Best Practices

When implementing WAF with your serverless architecture, consider the following best practices:

• Regularly review and update your WAF rules.
• Enable logging to monitor and analyze web traffic.
• Use rate limiting to prevent DDoS attacks.
• Test your WAF configurations in a staging environment before production deployment.

FAQ