Kubernetes has received fixes for one of the most serious vulnerabilities ever found in the project to date. If left unpatched, the flaw could allow attackers to take over entire compute nodes.
“With a specially crafted request, users that are allowed to establish a connection through the Kubernetes API server to a backend server can then send arbitrary requests over the same connection directly to that backend, authenticated with the Kubernetes API server’s TLS credentials used to establish the backend connection,” the Kubernetes developers said in an advisory.
Furthermore, in default configurations, both authenticated and unauthenticated users are allowed to perform API discovery calls and could exploit this vulnerability to escalate their privileges. For example, attackers could list all pods on a node, could run arbitrary commands on those pods and could obtain the output of those commands.
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