Authorization Bypass Through User-Controlled Key

Summary

Envoy is a cloud-native high-performance edge/middle/service proxy. A security vulnerability in Envoy allows external clients to manipulate Envoy headers, potentially leading to unauthorized access or other malicious actions within the mesh. This issue arises due to Envoy's default configuration of internal trust boundaries, which considers all "RFC1918" private address ranges as internal. The default behavior for handling internal addresses in Envoy has been changed. Previously, "RFC1918" IP addresses were automatically considered internal, even if the "internal_address_config" was empty. The default configuration of Envoy will continue to trust internal addresses in this release, but it will not trust them by default in the next release. If you have the tooling, such as probes on your private network, which need to be treated as trusted (e.g., changing arbitrary "x-envoy" headers), please explicitly include those addresses or CIDR ranges in "internal_address_config". Successful exploitation could allow attackers to bypass security controls, access sensitive data, or disrupt services within the mesh, like Istio. This issue affects envoyproxy/envoy versions prior to 1.28.7, v1.29.0 prior to 1.29.9, v1.30.0 prior to v1.30.6, v1.31.0 prior to v1.31.2. Users are advised to upgrade. There are no known workarounds for this vulnerability.