CVE-2024-5042 is a medium-severity vulnerability identified in the Submariner project, a tool used for connecting Kubernetes clusters across different networks. The root cause is the assignment of unnecessary and overly permissive role-based access control (RBAC) permissions within Submariner's components. This misconfiguration allows an attacker who already has privileged access on a node to execute a malicious container. By doing so, the attacker can steal service account tokens, which are credentials used by Kubernetes pods to authenticate to the API server. With these tokens, the attacker can escalate their privileges and compromise other nodes within the cluster, potentially leading to full cluster takeover. The vulnerability affects Submariner versions from 0 up to 0.18.0-m0. The CVSS 3.1 score of 6.6 reflects that the attack vector is network-based but requires high privileges (PR:H) and has high attack complexity (AC:H). No user interaction is needed, and the scope is changed (S:C), meaning the attacker can impact resources beyond their initial privileges. No public exploits have been reported yet, but the vulnerability poses a significant risk in multi-cluster Kubernetes environments where Submariner is deployed. The lack of available patches at the time of reporting means organizations must rely on mitigating controls until updates are released.

For European organizations, especially those leveraging Kubernetes clusters interconnected via Submariner for hybrid or multi-cloud deployments, this vulnerability presents a risk of lateral movement and cluster-wide compromise. If exploited, attackers can steal service account tokens, undermining confidentiality by accessing sensitive data and integrity by manipulating cluster resources. The availability impact is low as the vulnerability does not directly enable denial of service. However, the potential for full cluster compromise can disrupt critical services and workloads. Organizations in sectors such as finance, telecommunications, and critical infrastructure that rely on Kubernetes for container orchestration are at heightened risk. The need for privileged access limits exposure somewhat, but insider threats or compromised privileged accounts could trigger exploitation. The interconnected nature of clusters in multi-cloud or multi-region setups common in Europe amplifies the potential blast radius. Additionally, regulatory requirements like GDPR increase the consequences of data breaches stemming from such compromises.

European organizations should immediately audit and tighten RBAC permissions within their Submariner deployments, ensuring the principle of least privilege is strictly enforced. Restrict the ability to run containers on nodes to only trusted administrators and service accounts. Implement strong monitoring and alerting for unusual container creation or service account token usage. Use Kubernetes Pod Security Policies or equivalent admission controllers to prevent unauthorized container execution. Network segmentation between clusters and nodes can limit lateral movement. Rotate service account tokens regularly and consider using short-lived tokens or bound tokens to reduce token theft impact. Until patches are available, consider disabling or limiting Submariner components that require elevated privileges. Engage with the Submariner community or vendor for timely updates and apply patches as soon as they are released. Conduct thorough incident response planning focused on container and token compromise scenarios.