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7 Expert Tips for Optimizing AWS WAF Pricing

Navigating the intricate landscape of cloud services can be a daunting endeavor, especially when considering the cost implications. Among the many services offered by Amazon Web Services (AWS), the Web Application Firewall (WAF) stands out as a critical tool for safeguarding web applications.

43% of breaches involve web applications. In response to the relentless rate of attacks, the WAF market is expected to grow to $8.06 billion by 2026. AWS stands out as one of the best WAF solutions, with impressive features like rule-based filtering rate limiting, logging, monitoring, and custom rules to improve the security of web applications.

However, it's a good idea to maintain caution when utilizing these features since using AWS WAF can also be a double-edged sword regarding costs. So, in this article, we'll discuss expert tips for optimizing AWS WAF costs to help you improve application security while maintaining an affordable bill.

What is AWS WAF?

AWS WAF is a cloud-based security service offered by AWS, designed to shield web applications from malicious activities and OWASP Top 10 cyber attacks. It inspects incoming web traffic and applies a set of predefined or custom rules created by users. These rules can filter, monitor, or block requests based on various criteria like IP addresses, HTTP headers, query strings, etc.

For example, you can use AWS WAF to defend against SQL injection attacks by configuring rules to inspect incoming requests for SQL injection patterns or specific keywords often associated with such attacks. Similarly, you can use AWS WAF to protect applications from XSS attacks by inspecting requests for malicious JavaScript code or script tags.

What are the Benefits of AWS WAF?

  • Protection against attacks like SQL injection and XSS.

  • Automatically detects and mitigates threats, including DDoS attacks.

  • You can customize security rules to your application's needs.

  • Easily integrates with AWS services.

  • Provides real-time visibility into traffic and security events.

7 Expert Tips for Optimizing AWS WAF Pricing

While AWS WAF provides essential web application security benefits, it's equally important to consider the cost aspects. Here are seven tips you can use to optimize AWS WAF costs.

1. Understand the Pricing Model

Understanding AWS WAF's pricing model is crucial for cost-effective security. AWS WAF charges users based on three main components:

  • $5.00 per month for each Web ACL you create.

  • $1.00 per month for every rule added to a Web ACL.

  • $0.60 for every 1 million web requests processed by Web ACL.

Best practices:

Web ACLs act as rule sets for inspecting and filtering web traffic. Since each Web ACL increases your expenses, it's vital to consolidate them when possible. Combining multiple rule sets into a single WebACL can help minimize costs and simplify security configurations.

Also, you have to pay for each web request for the service processes. The cost depends on the total number of requests, making managing and optimizing your web traffic essential. Implement strategies like rate-based rules or AWS Shield to control costs associated with processing high volumes of web requests while maintaining adequate security measures.

2. Architectural Considerations

Before using AWS WAF, you need to make architectural decisions, like how AWS WAF integrates into your system, where and how to deploy it, and structuring your resources to balance security needs. These decisions can significantly influence the efficiency and cost-effectiveness of AWS WAF.

Best practices:

  • Don't use WAF for all traffic, which can lead to unnecessary costs.

  • Use other services like Amazon CloudFront to reduce the number of processed requests.

  • Configure AWS WAF to scale up or down based on the traffic, which avoids resource overprovisioning and causing unnecessary expenses during low-traffic periods.

  • If you operate in multiple regions, compare the cost between using a global ACL and deploying them regionally.

3. Monitor & Set Alerts

Monitoring activity and setting up alerts for AWS WAF isn't just about security; it's also a fundamental practice for cost optimization. With Amazon CloudWatch, you gain insights into metrics like rule evaluations, web request volumes, and resource utilization set alerts to avoid unexpected usage and reduce costs.

Best practices:

  • Select metrics that are directly related to your security and cost concerns.

  • Define appropriate cost thresholds to trigger alerts when specific conditions or anomalies are met.

  • Develop escalation procedures for handling significant cost overruns.

  • Regularly test and validate your alerts to ensure they work as intended.

4. Clean Up Unused Resources

Cleaning up unused resources is a great way to save money. When an application evolves and security requirements change, you may end up with obsolete or redundant WAF components, like rules, rule groups, or web ACLs.

These resources can silently inflate your AWS bill, as AWS charges for the provisioned resources regardless of utilization. You can shut down these resources by periodically conducting resource audits to save a significant cost.

Best practices:

  • Implement a consistent tagging strategy to categorize and track resources.

  • Maintain documentation about the purpose and owner of each resource.

  • Use tools like AWS Config to automate the cleaning process.

  • Ensure you have backups or snapshots before deleting any resource.

  • Analyze dependencies to ensure that removing one resource won't affect other parts.

5. Use AWS Savings Plans or Reserved Capacity

Using savings plans or reserved capacity can significantly lower organizational costs as their applications scale. These plans help you predict, reduce, and optimize spending, which is crucial for financial efficiency.

Best practices:

While AWS WAF does not have a dedicated capacity option, you can strategically use those mechanisms when combining AWS WAF with other services like Amazon CloudFront or AWS Elastic Load Balancing.

For example, consider an e-commerce application that relies on an Amazon CloudFront distribution. Using a reserved capacity for CloudFront, you can limit the traffic passes through AWS WAF and significantly save request processing costs.

6. Regional vs. Global ACLs

As mentioned in the architectural considerations section, AWS WAF provides two types of ACLs: regional and global. Here's a comparison of the two:

When it comes to cost optimization, there are a few things you need to consider when picking between these two:

  • Application Distribution: If your applications span multiple regions, using global ACLs will be the cost-optimized approach since you can use consistent rules.

  • Operational Overhead: Although regional rule sets offer flexibility in defining rules based on usage patterns, they may require additional effort on rule configuration, leading to higher costs.

  • Hybrid Approaches: You can use global ACLs for main security policies that apply globally and save money while using regional ACLs for fine-tuning rules for specific regional applications.

7. Use Rule Group

Utilizing rule groups is a great way to optimize AWS WAF costs. Instead of handling individual WAF rules separately, rule groups allow you to organize and consolidate rules with similar functionalities into a single, reusable entity. This approach simplifies rule management and reduces pricing complexity, as AWS charges based on the number of rule evaluations.

Furthermore, rule groups enhance the flexibility and maintainability of your WAF configuration, making it easier to adapt to changing security requirements and efficiently manage a growing number of rules while keeping a keen eye on your budget.


open-appsec is an open-source project that builds on machine learning to provide pre-emptive web app & API threat protection against OWASP-Top-10 and zero-day attacks. It simplifies maintenance as there is no threat signature upkeep and exception handling, like common in many WAF solutions.

To learn more about how open-appsec works, see this White Paper and the in-depth Video Tutorial. You can also experiment with deployment in the free Playground.


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