Rancher allows privilege escalation in Windows nodes due to Insecure Access Control Lists

Overview

Impact

A vulnerability has been identified whereby Rancher Manager deployments containing Windows nodes have weak Access Control Lists (ACL), allowing BUILTIN\Users or NT AUTHORITY\Authenticated Users to view or edit sensitive files which could lead to privilege escalation.

The affected files include binaries, scripts, configuration and log files:

C:\etc\rancher\wins\config
C:\var\lib\rancher\agent\rancher2_connection_info.json
C:\etc\rancher\rke2\config.yaml.d\50-rancher.yaml
C:\var\lib\rancher\agent\applied\*-*-applied.plan
C:\usr\local\bin\rke2
C:\var\lib\rancher\capr\idempotence\idempotent.sh

RKE2 nodes expand the list to include the files below:

C:\etc\rancher\node\password
C:\var\lib\rancher\rke2\agent\logs\kubelet.log
C:\var\lib\rancher\rke2\data\v1.**.**-rke2r*-windows-amd64-*\bin\*
C:\var\lib\rancher\rke2\bin\*

This vulnerability is exclusive to deployments that contain Windows nodes. Linux-only environments are not affected by it.

Please consult the associated MITRE ATT&CK - Technique - Exploitation for Privilege Escalation for further information about this category of attack.

Patches

Patched versions include Rancher Manager 2.8.9 and 2.9.3. For RKE2 Windows nodes, please refer to its specific advisory. No patches are available for 2.7, therefore users are urged to upgrade to newer minor versions or to apply the manual workaround below.

Workarounds

Users are advised to upgrade to a patched version of Rancher Manager. When that is not possible, users can enforce stricter ACLs for all sensitive files affected by this Security Advisory running this PowerShell script as an Administrator on each node.

References

• CVE-2023-32197
• RKE2’s GHSA-x7xj-jvwp-97rv

For more information

If you have any questions or comments about this advisory:

• Reach out to the SUSE Rancher Security team for security related inquiries.
• Open an issue in the Rancher repository.
• Verify with our support matrix and product support lifecycle.

Affected packages

• github.com/rancher/rancher >= 2.7.0, < 2.8.9
• github.com/rancher/rancher >= 2.9.0, < 2.9.3

Remediation

Upgrade to a patched release:

• github.com/rancher/rancher 2.8.9
• github.com/rancher/rancher 2.9.3