CVE-2023-41333: Bypass of namespace restrictions in CiliumNetworkPolicy

Vulnerability summary

CVE-2023-41333 is a high (CVSS 8.1) vulnerability in cilium. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40.6% of scored vulnerabilities.

Timeline

1. 26-09-2023
   PublishedVulnerability first disclosed.
2. 23-09-2024
   Last modifiedVulnerability information updated.

Description

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. An attacker with the ability to create or modify CiliumNetworkPolicy objects in a particular namespace is able to affect traffic on an entire Cilium cluster, potentially bypassing policy enforcement in other namespaces. By using a crafted `endpointSelector` that uses the `DoesNotExist` operator on the `reserved:init` label, the attacker can create policies that bypass namespace restrictions and affect the entire Cilium cluster. This includes potentially allowing or denying all traffic. This attack requires API server access, as described in the Kubernetes API Server Attacker section of the Cilium Threat Model. This issue has been resolved in Cilium versions 1.14.2, 1.13.7, and 1.12.14. As a workaround an admission webhook can be used to prevent the use of `endpointSelectors` that use the `DoesNotExist` operator on the `reserved:init` label in CiliumNetworkPolicies.

• CWE-306Missing Authentication for Critical FunctionThe product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.