Security Bulletin: IBM Cloud Kubernetes Service is affected by two containerd security vulnerabilities (CVE-2023-28642) (CVE-2023-27561)

Summary

IBM Cloud Kubernetes Service is affected by two security vulnerabilities found in containerd where (1) runc could allow a remote attacker to bypass security restrictions, caused by a symbolic link following vulnerability (CVE-2023-28642) and (2) runc could allow a local authenticated attacker to gain elevated privileges on the system, caused by improper access control (CVE-2023-27561).

Vulnerability Details

CVEID: CVE-2023-28642
Description: runc could allow a remote attacker to bypass security restrictions, caused by a symbolic link following vulnerability. By creating a symbolic link inside a container to the /proc directory, an attacker could exploit this vulnerability to bypass AppArmor and SELinux protections.
CVSS Base Score: 6.1
CVSS Temporal Score:<https://exchange.xforce.ibmcloud.com/vulnerabilities/251539&gt; for more information
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L)

CVEID: CVE-2023-27561
Open Container Initiative runc could allow a local authenticated attacker to gain elevated privileges on the system, caused by improper access control in libcontainer/rootfs_linux.go. By sending a specially-crafted request, an authenticated attacker could exploit this vulnerability to gain elevated privileges to run custom images.
CVSS Base Score: 7.8
CVSS Temporal Score:<https://exchange.xforce.ibmcloud.com/vulnerabilities/249173&gt;[](&lt;https://exchange.xforce.ibmcloud.com/vulnerabilities/236344&gt;) for more information
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

IBM Cloud Kubernetes Service 1.26-1.26.4_1536
IBM Cloud Kubernetes Service 1.25-1.25.8_1539
IBM Cloud Kubernetes Service 1.24-1.24.12_1562
IBM Cloud Kubernetes Service 1.5-1.23

Remediation/Fixes

Updates for IBM Cloud Kubernetes Service cluster worker nodes at version 1.24, 1.25, or 1.26 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:

1.26.5_1538
1.25.8_1541
1.24.12_1564

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

Complete CVSS v3 Guide
On-line Calculator v3

Off

CVE-2023-28642: runc AppArmor bypass with symlinked /proc
CVE-2023-27561: Opencontainers runc Incorrect Authorization vulnerability

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.

[{“Business Unit”:{“code”:“BU059”,“label”:“IBM Software w/o TPS”},“Product”:{“code”:“SSJTBP”,“label”:“IBM Cloud Kubernetes Service and Red Hat OpenShift on IBM Cloud”},“Component”:“–”,“Platform”:[{“code”:“PF025”,“label”:“Platform Independent”}],“Version”:“All Versions”,“Edition”:“”,“Line of Business”:{“code”:“LOB21”,“label”:“Public Cloud Platform”}}]