Shared Surface · Registry
Container Registries
A shared container registry is a single supply-chain choke point. One compromised push, often via CI, flows out to every tenant that pulls the affected image.
Whilst this isn’t directly part of the Kubernetes cluster, pretty much every cluster relies on one or more container registries and they’ll often share a registry across tenants. An oblique example of this was the OpenAI Huggingface attack, where a large set of containerized agents used a shared Artifactory registry as an ad-hoc message board.
This makes registries another shared surface where a malicious tenant might look to expand their access. Compromising a base image used across the cluster can easily lead to privilege escalation, and there can be multiple routes to this access either directly via access to the container registry API or indirectly via something like Continuous Integration systems.