CVE-2024-22032: Rancher's RKE1 Encryption Config kept in plain-text within cluster AppliedSpec

This issue is only relevant to clusters provisioned using RKE1 with secrets encryption configuration enabled.

A vulnerability has been identified in which an RKE1 cluster keeps constantly reconciling when secrets encryption configuration is enabled (please see the RKE documentation). When reconciling, the Kube API secret values are written in plaintext on the AppliedSpec. Cluster owners, Cluster members, and Project members (for projects within the cluster), all have RBAC permissions to view the cluster object from the apiserver.

This could lead to an unauthorized user gaining access to the entire secrets encryption config specific for the cluster, only on the applied spec.

Since this affects only custom encryption configurations, users need to manually rotate the keys by editing the cluster. For more information, please refer to the RKE secrets encryption documentation.

The full custom configuration example:

services:
kube-api:
secrets_encryption_config:
enabled: true
custom_config:
apiVersion: apiserver.config.k8s.io/v1
kind: EncryptionConfiguration
resources:
- resources:
- secrets
providers:
- aescbc:
keys:
- name: k-fw5hn
secret: RTczRjFDODMwQzAyMDVBREU4NDJBMUZFNDhCNzM5N0I= #<--- needs to be changed
- identity: {}

Please consult the associated MITRE ATT&CK - Technique - Unsecured Credentials for further information about this category of attack.