Skip to content

RKE1 Encryption Config kept in plain-text within cluster AppliedSpec

Moderate
pdellamore published GHSA-q6c7-56cq-g2wm Jun 17, 2024

Package

gomod rancher/rancher (Go)

Affected versions

>= 2.7.0, < 2.7.14
>=2.8.0, <2.8.5

Patched versions

2.7.14
2.8.5

Description

Impact

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.

Patches

To address this issue, the fix introduces a new change that copies the AppliedSpec before mutating. As such, the next time the cluster is reconciled and the AppliedSpec is set, all references to sensitive data will be removed.

Patched versions include releases 2.7.14 and 2.8.5.

Workarounds

There are no workarounds for this issue. Users are recommended to upgrade, as soon as possible, to a version of RKE/Rancher Manager which contains the fixes.

References

If you have any questions or comments about this advisory:

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVE ID

CVE-2024-22032