CVE-2024-47825

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Starting in version 1.14.0 and prior to versions 1.14.16 and 1.15.10, a policy rule denying a prefix that is broader than `/32` may be ignored if there is a policy rule referencing a more narrow prefix (`CIDRSet` or `toFQDN`) and this narrower policy rule specifies either `enableDefaultDeny: false` or `- toEntities: all`. Note that a rule specifying `toEntities: world` or `toEntities: 0.0.0.0/0` is insufficient, it must be to entity `all`.This issue has been patched in Cilium v1.14.16 and v1.15.10. As this issue only affects policies using `enableDefaultDeny: false` or that set `toEntities` to `all`, some workarounds are available. For users with policies using `enableDefaultDeny: false`, remove this configuration option and explicitly define any allow rules required. For users with egress policies that explicitly specify `toEntities: all`, use `toEntities: world`.

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Starting in version 1.14.0 and prior to versions 1.14.16 and 1.15.10, a policy rule denying a prefix that is broader than `/32` may be ignored if there is a policy rule referencing a more narrow prefix (`CIDRSet` or `toFQDN`) and this narrower policy rule specifies either `enableDefaultDeny: false` or `- toEntities: all`. Note that a rule specifying `toEntities: world` or `toEntities: 0.0.0.0/0` is insufficient, it must be to entity `all`.This issue has been patched in Cilium v1.14.16 and v1.15.10. As this issue only affects policies using `enableDefaultDeny: false` or that set `toEntities` to `all`, some workarounds are available. For users with policies using `enableDefaultDeny: false`, remove this configuration option and explicitly define any allow rules required. For users with egress policies that explicitly specify `toEntities: all`, use `toEntities: world`.

Cilium's CIDR deny policies may not take effect when a more narrow CIDR allow is present in github.com/cilium/cilium

### Impact A policy rule denying a prefix that is broader than /32 may be ignored if there is - A policy rule referencing a more narrow prefix (`CIDRSet` or `toFQDN`) **and** - This narrower policy rule specifies either `enableDefaultDeny: false` or `- toEntities: all` Note that a rule specifying `toEntities: world` or `toEntities: 0.0.0.0/0` is insufficient, it must be to entity `all`. As an example, given the below policies, traffic is allowed to 1.1.1.2, when it should be denied: ``` apiVersion: cilium.io/v2 kind: CiliumClusterwideNetworkPolicy metadata: name: block-scary-range spec: endpointSelector: {} egressDeny: - toCIDRSet: - cidr: 1.0.0.0/8 --- apiVersion: cilium.io/v2 kind: CiliumNetworkPolicy metadata: name: evade-deny spec: endpointSelector: {} egress: - toCIDR: - 1.1.1.2/32 - toEntities: - all ``` ### Patches This issue affects: - Cilium v1.14 between v1.14.0 and v1.14.15 inclusive - Cilium v1.15 between v1.15.0 and v1.15.9 inclusive This issue has been patched in: - Cilium v1.14.16 - Cilium v1.15.10 ### Workarounds Users with policies using `enableDefaultDeny: false` can work around this issue by removing this configuration option and explicitly defining any allow rules required. No workaround is available to users with egress policies that explicitly specify `toEntities: all`. ### Acknowledgements The Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to @squeed, @christarazi, and @jrajahalme for their work in triaging and resolving this issue. ### For more information If you have any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/#slack). If you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and your report will be treated with top priority.

Cilium es una solución de redes, observabilidad y seguridad con un plano de datos basado en eBPF. A partir de la versión 1.14.0 y antes de las versiones 1.14.16 y 1.15.10, una regla de política que deniegue un prefijo más amplio que `/32` puede ignorarse si hay una regla de política que haga referencia a un prefijo más estrecho (`CIDRSet` o `toFQDN`) y esta regla de política más estrecha especifica `enableDefaultDeny: false` o `- toEntities: all`. Tenga en cuenta que una regla que especifique `toEntities: world` o `toEntities: 0.0.0.0/0` no es suficiente, debe ser para la entidad `all`. Este problema se ha corregido en Cilium v1.14.16 y v1.15.10. Como este problema solo afecta a las políticas que utilizan `enableDefaultDeny: false` o que establecen `toEntities` en `all`, hay algunas soluciones alternativas disponibles. Para los usuarios con políticas que utilizan `enableDefaultDeny: false`, elimine esta opción de configuración y defina explícitamente las reglas de permiso requeridas. Para los usuarios con políticas de salida que especifican explícitamente `toEntities: all`, utilice `toEntities: world`.