CVE-2025-25294

Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. In all Envoy Gateway versions prior to 1.2.7 and 1.3.1 a default Envoy Proxy access log configuration is used. This format is vulnerable to log injection attacks. If the attacker uses a specially crafted user-agent which performs json injection, then he could add and overwrite fields to the access log. This vulnerability is fixed in 1.3.1 and 1.2.7. One can overwrite the old text based default format with JSON formatter by modifying the "EnvoyProxy.spec.telemetry.accessLog" setting.

Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. In all Envoy Gateway versions prior to 1.2.7 and 1.3.1 a default Envoy Proxy access log configuration is used. This format is vulnerable to log injection attacks. If the attacker uses a specially crafted user-agent which performs json injection, then he could add and overwrite fields to the access log. This vulnerability is fixed in 1.3.1 and 1.2.7. One can overwrite the old text based default format with JSON formatter by modifying the "EnvoyProxy.spec.telemetry.accessLog" setting.

Envoy Gateway Log Injection Vulnerability in github.com/envoyproxy/gateway

### Impact In all Envoy Gateway versions prior to 1.2.7 and 1.3.1 a default Envoy Proxy access log configuration is used. This format is vulnerable to log injection attacks. If the attacker uses a specially crafted user-agent which performs json injection, then he could add and overwrite fields to the access log. Examples of attacks include: - Using following string as user agent : `HELLO-WORLD", "evil-ip": "1.1.1.1", "x-forwarded-for": "1.1.1.1` would lead to setting of new access log properties and overwrite of existing properties. Existing properties such as the value of the X-Forwarded-For header may have importance for security analysis of access logs, and their overwrite can be used to hide malicious activity. - Using the following string as user-agent : `"` which renders an invalid json document. The invalid document may fail to be processed by observability solutions, which would allow attacker to hide malicious activity. ### Patches 1.3.1, 1.2.7 ### Fix Using JSON format as the default format for access logs. The logged document will contain the same key and values as before. Only the order of properties is different inside the logged document. ### Workaround One can overwrite the old text based default format with JSON formatter by setting the following property: "EnvoyProxy.spec.telemetry.[accessLog](https://gateway.envoyproxy.io/v1.3/api/extension_types/#proxyaccesslog)" to ``` settings: - format: type: JSON json: start_time: '%START_TIME%' method: '%REQ(:METHOD)%' x-envoy-origin-path: '%REQ(X-ENVOY-ORIGINAL-PATH?:PATH)%' protocol: '%PROTOCOL%' response_code: '%RESPONSE_CODE%' response_flags: '%RESPONSE_FLAGS%' response_code_details: '%RESPONSE_CODE_DETAILS%' connection_termination_details: '%CONNECTION_TERMINATION_DETAILS%' upstream_transport_failure_reason: '%UPSTREAM_TRANSPORT_FAILURE_REASON%' bytes_received: '%BYTES_RECEIVED%' bytes_sent: '%BYTES_SENT%' duration: '%DURATION%' x-envoy-upstream-service-time: '%RESP(X-ENVOY-UPSTREAM-SERVICE-TIME)%' x-forwarded-for: '%REQ(X-FORWARDED-FOR)%' user-agent: '%REQ(USER-AGENT)%' x-request-id: '%REQ(X-REQUEST-ID)%' :authority: '%REQ(:AUTHORITY)%' upstream_host: '%UPSTREAM_HOST%' upstream_cluster: '%UPSTREAM_CLUSTER%' upstream_local_address: '%UPSTREAM_LOCAL_ADDRESS%' downstream_local_address: '%DOWNSTREAM_LOCAL_ADDRESS%' downstream_remote_address: '%DOWNSTREAM_REMOTE_ADDRESS%' requested_server_name: '%REQUESTED_SERVER_NAME%' route_name: '%ROUTE_NAME%' ``` see API definition [here](https://gateway.envoyproxy.io/v1.3/api/extension_types/#proxyaccesslogformat) ### References _Are there any links users can visit to find out more?_

Envoy Gateway es un proyecto de código abierto para administrar Envoy Proxy como una puerta de enlace de aplicaciones independiente o basada en Kubernetes. En todas las versiones de Envoy Gateway anteriores a 1.2.7 y 1.3.1 se utiliza una configuración de registro de acceso de Envoy Proxy predeterminada. Este formato es vulnerable a ataques de inyección de registros. Si el atacante utiliza un agente de usuario especialmente manipulado que realiza una inyección JSON, podría agregar y sobrescribir campos en el registro de acceso. Esta vulnerabilidad se solucionó en 1.3.1 y 1.2.7. Se puede sobrescribir el antiguo formato predeterminado basado en texto con el formateador JSON modificando la configuración "EnvoyProxy.spec.telemetry.accessLog".