AWS WAF: Web Application Firewall Configuration and Tuning

Part of the Cybersecurity Skills Guide — This article is one deep-dive in our complete guide series.

By HADESS Team | February 28, 2026 | Updated: February 28, 2026 | 5 min read

AWS WAF sits in front of CloudFront, ALB, API Gateway, and AppSync to filter malicious HTTP requests. It is not a replacement for secure application code, but it provides a defense layer that can block known attack patterns, rate-limit abusive clients, and stop bot traffic before it reaches your application.

Rule Groups

WAF uses web ACLs containing rule groups. Each rule group contains individual rules that inspect request components (headers, body, URI, query string) and take actions (allow, block, count, CAPTCHA).

Organize your rules into logical groups:

• IP reputation: Block known malicious IPs using AWS managed IP reputation lists or your own threat intelligence
• Rate limiting: Throttle abusive clients before they overwhelm your application
• Application-specific: Custom rules targeting your application’s attack surface
• Bot management: Separate legitimate bots (search engines) from malicious ones (scrapers, credential stuffers)

Rule evaluation order matters. Rules are evaluated in priority order within a web ACL. Put IP blocklists first (cheap to evaluate, high confidence), then rate limits, then managed rules, then custom rules.

AWS Managed Rules

AWS provides managed rule groups that cover common attack categories:

• Core Rule Set (CRS): SQLi, XSS, and other OWASP Top 10 patterns
• Known Bad Inputs: Patterns associated with exploitation of specific CVEs
• SQL Database: SQL injection patterns beyond the CRS
• Linux/POSIX/Windows OS: Command injection patterns for specific platforms

Start with managed rules in Count mode, not Block. Review the requests that would have been blocked for false positives over a week or two. Then switch to Block mode and add exclusions for any legitimate traffic that gets caught.

Managed rules update automatically, but updates can introduce false positives. Set up CloudWatch alarms on sudden spikes in blocked requests after a rule group version change.

Rate Limiting

Rate-based rules block clients that exceed a request threshold within a 5-minute window. Set rate limits based on your application’s normal traffic patterns.

Use multiple rate-based rules at different thresholds:

• A high threshold (2000 requests/5 min) applied globally to catch volumetric attacks
• A lower threshold (100 requests/5 min) on authentication endpoints to slow credential stuffing
• An even lower threshold (20 requests/5 min) on password reset and account creation endpoints

Scope rate limits by IP, by IP with a forwarded header (for clients behind proxies), or by custom keys like session cookies or API keys.

Bot Control

The Bot Control managed rule group identifies and categorizes bot traffic. It distinguishes between verified bots (Googlebot, Bingbot), self-identifying bots, and likely automated traffic that does not identify itself.

Use Bot Control’s targeted inspection mode for sensitive endpoints like login pages and checkout flows. This applies more aggressive challenge mechanisms (CAPTCHA, silent challenges) to traffic that looks automated.

Logging and Analysis

Enable WAF logging to S3 through Kinesis Data Firehose. Log all requests, not just blocked ones. The logs include the full request details and which rules matched, giving you the data to tune your rules.

Analyze WAF logs for patterns: which rules generate the most blocks, which source IPs appear most frequently, and whether your rate limits are set appropriately. Use this data to refine your configuration continuously.

Next Steps

• Evaluate your web security skills with the assessment tool
• Explore application and web security topics in the skills library
• Use the coaching tool to build a study plan covering WAF and web application security

Related Guides in This Series

• Active Directory Security: Attack Paths and Hardening — HADESS | 2026
• AWS ALB Security: TLS, Authentication, and Access Controls — HADESS | 2026
• AWS CloudTrail: Log Analysis and Security Monitoring — HADESS | 2026

Take the Next Step

Browse 80+ skills on HADESS. Go to the browse 80+ skills on hadess on HADESS.

See your certification roadmap. Check out the see your certification roadmap.

Get started free — Create your HADESS account and access all career tools.

Frequently Asked Questions

How long does it take to learn this skill?

Most practitioners build working proficiency in 4-8 weeks of dedicated study with hands-on practice. Mastery takes longer and comes primarily through on-the-job experience.

Do I need certifications for this skill?

Certifications validate your knowledge to employers but are not strictly required. Hands-on experience and portfolio projects often carry more weight in technical interviews. Check the certification roadmap for relevant options.

What career paths use this skill?

Explore the career path explorer to see which roles require this skill and how it fits into different cybersecurity specializations.

—

HADESS Team consists of cybersecurity practitioners, hiring managers, and career strategists who have collectively spent 50+ years in the field.