IBM Cloud Kubernetes Service is affected by a security vulnerability in Project Calico, the network CNI plugin used in IBM Cloud Kubernetes Service. In some scenarios, Calico will write configuration data in log files including service account tokens included in the configuration. This will expose Calico service account tokens in log files which could lead to unauthorized cluster access or privilege escalation if users are able to view log files containing these tokens.
DESCRIPTION: Project Calico could allow a remote attacker to bypass security restrictions, caused by the writing of configuration data and service account tokens in the log file. By accessing the log file, an attacker could exploit this vulnerability to gain access to the cluster or elevated privileges on the system.
CVSS Base Score: 5.5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/152996 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)
Affected Products and Versions
IBM Cloud Kubernetes Service - Kubernetes 1.9
IBM Cloud Kubernetes Service - Kubernetes 1.10, 1.11 or 1.12 upgraded from Kubernetes 1.9
Clusters initially provisioned with Kubernetes 1.10 or later are not affected. However logs for clusters upgraded to Kubernetes 1.10 or later might contain service account tokens written to the logs while the cluster was running Kubernetes 1.9.
IBM Cloud Kubernetes Service clusters currently running Kubernetes 1.9 have been updated so that service account tokens are no longer logged.
The Calico service account tokens for clusters running Kubernetes 1.9, 1.10, 1.11 and 1.12 have been deleted and recreated so that any previously logged token is now invalid.
In some rare situations IBM Cloud Kubernetes Service might not have been able to update a cluster. To verify your clusters are no longer exposed run the following IBM Cloud CLI command to confirm the currently running version:
ic ks clusters
If the Kubernetes version is at one of the following patch levels or later the upgrade has been completed and any Calico service account tokens appearing in log files are invalid:
If your cluster has not been updated you can manually update your cluster with the following IBM Cloud CLI command:
ic ks cluster-update --cluster <CLUSTER_ID>
For further assistance open open an IBM Cloud Support case. Include your region, cluster ID, and mention HA master update in the case.
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*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.
Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.
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06 December 2018