Security Bulletin
Summary
IBM Cloud Kubernetes Service is affected by a security vulnerability found in containerd that could result in file permission changes for existing files in the host's filesystem (CVE-2021-32760)
Vulnerability Details
CVEID: CVE-2021-32760
Description: Containerd could allow a remote attacker to gain elevated privileges on the system, caused by improper file permissions. By pulling and extracting a specially-crafted container image, an attacker could exploit this vulnerability to perform Unix file permission changes for existing files in the host's filesystem.
CVSS Base Score: 9.8
CVSS Temporal Score: https://exchange.xforce.ibmcloud.com/vulnerabilities/205942 for more information
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Affected Products and Versions
IBM Cloud Kubernetes Service 1.21.0-1.21.2_1524
IBM Cloud Kubernetes Service 1.20.0-1.20.8_1546
IBM Cloud Kubernetes Service 1.19.0-1.19.12_1553
IBM Cloud Kubernetes Service 1.5-1.18
Remediation/Fixes
Updates for IBM Cloud Kubernetes Service cluster worker nodes at versions 1.19 or later are available that fix this vulnerability. Customers must update worker nodes created before the fix was available to address the vulnerability. See updating worker nodes for details on updating worker nodes. To verify your cluster worker nodes have been updated, use the following IBM Cloud CLI command to confirm the currently running versions:
ibmcloud ks workers --cluster <cluster name or ID>
If the versions are at one of the following patch levels or later, the cluster worker nodes have the fix:
1.21.3_1526
1.20.9_1548
1.19.13_1555
Customers running IBM Cloud Kubernetes Service clusters at version 1.17 or 1.18 must upgrade to version 1.19. Please review the documentation before starting an upgrade since additional actions may be required.
Customers running IBM Cloud Kubernetes Service clusters at version 1.16 or earlier must create a new cluster and deploy their apps to the new cluster.
IBM Cloud Kubernetes Service versions 1.17 and earlier are no longer supported, and version 1.18 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
*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:
06 August 2021
UID
ibm16478995