high

Azure Cloud Shell and Container Instances breakout

Published Mon, Feb 15th, 2021
Platforms

Summary

An attacker could gain root privileges on their Azure Cloud Shell container, escape from the container, and then gain root privileges on the underlying node, the root cause being an insecure kubelet port (10250), among other cluster misconfigurations. Once they could access the node filesystem, an attacker could extract kubelet API credentials which allowed listing all pods and nodes in the cluster, including those belonging to other tenants. Moreover, an attacker could bypass RBAC policies in the cluster by deploying a pod with the "NodeSelector" flag, and thereby escalate their privileges to root on other tenants' containers (the same issue affected Azure Container Instances).

Affected Services

Cloud Shell, Container Instances

Remediation

None required

Tracked CVEs

No tracked CVEs

References

Disclosure Date
Mon, Jan 20th, 2020
Exploitablity Period
until January 30th, 2020
Known ITW Exploitation
-
Detection Methods
-
Discovered by
Chen Cohen, eBay