CVE-2024-45806

A vulnerability was found in Envoy that 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 while in this release and it will not trust them by default in next release. If you have tooling such as probes on your private network which need to be treated as trusted such as changing arbitrary x-envoy headers, please explicitly include those addresses or CIDR ranges into internal_address_config. Successful exploitation could allow attackers to bypass security controls, access sensitive data, or disrupt services within the mesh, like Istio.

Mitigation

This flaw can be mitigated by configuring envoy to treat all IPs as external. This is done by setting the internal_address_config range for envoy to 0.0.0.0/32.