Detailed info: Kubernetes issue 71411
If you are running any unpatched versions of Kubernetes, you must update now. Anyone might be able to send commands directly to your backend through a forged network request, without even triggering a single line in the log, making their attack practically invisible!
If you are running a version of Kubernetes below 1.10... there is no help for you. Upgrade to a newer version, e.g. 1.12.3.
This post was written by @filthyranter