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Security Bulletin: IBM Cloud Kubernetes Service is affected by a CNI security vulnerability

Created by Sharon Singer on
Published URL:
https://www.ibm.com/support/pages/node/879585
879585

Security Bulletin


Summary

IBM Cloud Kubernetes Service is affected by a CNI security vulnerability which could result in weaker than expected security.

Vulnerability Details

CVE-ID: CVE-2019-9946
Description: Kubernetes could provide weaker than expected security, caused by an interaction when paired with the embedded CNI (Container Networking Interface) that uses the portmap plugin. The portmap plugin inserts rules at the front of the iptables nat chains which would take precedence over the KUBE- SERVICES chain. The HostPort/portmap rule allows for matching of incoming traffic even if there are better fitting, more specific service definition rules like NodePorts later in the chain.
CVSS Base Score: 5.3
CVSS Temporal Score: https://exchange.xforce.ibmcloud.com/vulnerabilities/158803 for more information
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)

Affected Products and Versions

IBM Cloud Kubernetes Service 1.13.0-1.13.4
IBM Cloud Kubernetes Service 1.12.0-1.12.6
IBM Cloud Kubernetes Service 1.11.0-1.11.8
IBM Cloud Kubernetes Service 1.5-1.10

Remediation/Fixes

IBM Cloud Kubernetes Service clusters at versions 1.11 and later have been updated to address this vulnerability. To resolve any existing exposure to this vulnerability, you must reboot or update your worker nodes.  See Updating worker nodes for details on updating worker nodes.  To verify your clusters have been updated, use the following IBM Cloud CLI commands to confirm the currently running versions:

ibmcloud ks clusters
ibmcloud ks workers --cluster <cluster name or ID>
If your master and worker node versions are at one of the following levels or later, you are no longer exposed to this vulnerability:
1.11.9
1.12.7
1.13.5
If one or more of your clusters is at version 1.11, 1.12 or 1.13 and has not been automatically updated then use the following IBM Cloud CLI command to complete the update, replacing "1.##" with the target version. After the update is complete, you must also reboot or update your worker nodes. See Updating worker nodes for details on updating worker nodes.
ibmcloud ks cluster-update --cluster <cluster name or ID> --kube-version 1.##
Customers running IBM Cloud Kubernetes Service clusters at version 1.10 must update their affected clusters to version 1.11 or 1.12. Customers running IBM Cloud Kubernetes Service clusters at version 1.7, 1.8 or 1.9 must update first to version 1.10 and then to version 1.11 or 1.12. Please review the update documentation for more information.

Customers running IBM Cloud Kubernetes Service clusters at version 1.5 must create a new cluster and migrate their apps to it.

Note: IBM Cloud Kubernetes Service versions 1.5, 1.7, 1.8 and 1.9 are no longer supported, and version 1.10 is deprecated.  See the IBM Cloud Kubernetes Service Version information and update actions documentation for more information about Kubernetes versions and version support policies.

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References

Complete CVSS v3 Guide
On-line Calculator v3

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Related Information

IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog

Change History

9 April 2019 : Original version published

*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.

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Document Information

Modified date:
09 April 2019

UID

ibm10879585

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