AWS WAF adds dynamic label interpolation for request/response handling

AI Impact Summary

AWS WAF now supports dynamic label interpolation, allowing a single rule to forward an entire label namespace to the origin via ${namespace:} in custom request headers, response headers, and response bodies. This enables sending signals such as IP reputation or JA3/JA4 fingerprints without creating separate rules for each value, simplifying rule maintenance and enabling adaptive responses at the origin (for example MFA gating). Built-in synthetic labels resolve context like client IP, WAF request ID, and TLS fingerprints, which can be embedded in error or challenge pages to aid users and operators in diagnosing false positives. The feature works across AWS Managed Rules, AWS Marketplace rule groups, and custom labels, automatically updates headers as the namespace grows, and incurs no additional cost in any AWS region.