Security Bulletin: Red Hat OpenShift on IBM Cloud is affected by Kubernetes API server security vulnerability (CVE-2019-11253)

Summary

Red Hat OpenShift on IBM Cloud is affected by a security vulnerability in the Kubernetes API server that exposes it to a denial of service attack via malicious YAML or JSON payloads (CVE-2019-11253).

Vulnerability Details

CVE-ID: CVE-2019-11253
Description: The Kubernetes API server is vulnerable to a denial of service, caused by a billion laughs attack, caused by an error when parsing YAML manifests. A remote attacker could exploit this vulnerability to cause a denial of service condition.
CVSS Base Score: 7.5
CVSS Temporal Score: <https://exchange.xforce.ibmcloud.com/vulnerabilities/168618&gt; 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:N/A:H)

Affected Products and Versions

Red Hat OpenShift on IBM Cloud 3.11.0-3.11.153

Remediation/Fixes

Updates for Red Hat OpenShift on IBM Cloud clusters at version 3.11 are available that fix this vulnerability. Red Hat OpenShift on IBM Cloud 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 Red Hat OpenShift on IBM Cloud clusters are no longer exposed to this vulnerability, use the following IBM Cloud CLI command to confirm your cluster master version:

ibmcloud ks clusters

If your cluster masters are at the following version or later, they are no longer exposed to this vulnerability:

3.11.154

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.

ibmcloud ks cluster-update --cluster <cluster name or ID> --kube-version 3.11_openshift

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

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

*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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