An issue was discovered in Rancher 2 through 2.1.5. Any project member with access to the default namespace can mount the netes-default service account in a pod, and then use that pod to execute administrative privileged commands against the k8s cluster. This could be mitigated by isolating the default namespace in a separate project, where only cluster admins can be given permissions to access. As of 2018-12-20, this bug affected ALL clusters created or imported by Rancher.

References

• https://nvd.nist.gov/vuln/detail/CVE-2018-20321
• rancher/rancher@6ea187f
• https://forums.rancher.com/c/announcements
• https://github.com/rancher/rancher/releases/tag/v2.1.6
• https://rancher.com/blog/2019/2019-01-29-explaining-security-vulnerabilities-addressed-in-rancher-v2-1-6-and-v2-0-11/