Security Bulletin
Summary
IBM Cloud Kubernetes Service is affected by a security vulnerability in the Kubernetes API server that enables a user to bypass the mountable secrets policy enforced by the ServiceAccount admission plugin when using ephemeral containers with the kubernetes.io/enforce-mountable-secrets annotation (CVE-2023-2728).
Vulnerability Details
CVEID: CVE-2023-2728
Description: Kubernetes could allow a remote authenticated attacker to bypass security restrictions, caused by a flaw when the ServiceAccount admission plugin and the kubernetes.io/enforce-mountable-secrets annotation are used together with ephemeral containers. By sending a specially crafted request, an attacker could exploit this vulnerability to bypass the mountable secrets policy to launch containers.
CVSS Base Score: 6.5
CVSS Temporal Score: https://exchange.xforce.ibmcloud.com/vulnerabilities/259627 for more information
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N)
Affected Products and Versions
IBM Cloud Kubernetes Service 1.26.0-1.26.5
IBM Cloud Kubernetes Service 1.25.0-1.25.10
IBM Cloud Kubernetes Service 1.24.0-1.24.14
IBM Cloud Kubernetes Service 1.5-1.23
Remediation/Fixes
Updates for IBM Cloud Kubernetes Service clusters at version 1.24 or later are available that fix this vulnerability. IBM Cloud Kubernetes Service will attempt to automatically apply the fix to your cluster master. There is no need to update cluster worker nodes for this vulnerability.
To verify your clusters are no longer exposed to this vulnerability, use the following IBM Cloud CLI command to confirm your cluster master versions:
ibmcloud ks clusters
If your cluster masters are at one of the following versions or later, they are no longer exposed to this vulnerability:
1.27.3_1529
1.26.6_1541
1.25.11_1549
1.24.15_1573
If one or more of your clusters has not had its master automatically updated then use the following IBM Cloud CLI command to complete the cluster master update, replacing 1.## with the target version.
ibmcloud ks cluster master update --cluster <cluster name or ID> --version 1.##
Customers running IBM Cloud Kubernetes Service clusters at version 1.23 must upgrade to version 1.24. Please review the documentation before starting an upgrade since additional actions may be required.
Customers running IBM Cloud Kubernetes Service clusters at version 1.22 or earlier must create a new cluster and deploy their apps to the new cluster.
IBM Cloud Kubernetes Service versions 1.23 and earlier are no longer supported. See the IBM Cloud Kubernetes Service version information and update actions documentation for more information about Kubernetes versions and version support policies.
Monitor IBM Cloud Status for Future Security Bulletins
Monitor the security notifications on the IBM Cloud Status page to be advised of future security bulletins.
References
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.
Product Synonym
IKS;
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Document Information
Modified date:
13 July 2023
UID
ibm17011039