Sneaking Around Docker and Kubernetes Isolation
Leaky Container
© Lead Image © costasz, 123RF.com
Docker containers and Kubernetes pods might not be as airtight as you think. We'll show you three potential attacks.
I recently became intrigued by a specific vulnerability affecting containers in Docker and pods in Kubernetes. The vulnerability, discovered in 2024, was quickly patched but considered just about as serious as vulnerabilities get. It was allocated the Common Vulnerabilities and Exposures (CVE) number CVE-2024-21626, and it received a severity score of 8.6 out of a possible 10 – very close to the 9.0 rating that would have marked it as critical.
The problem concerned a container runtime used in Kubernetes and Docker called runc. After a little eyestrain, having managed to simulate an attack using the CVE, I started reading about other common ways to attack Kubernetes clusters using a similar approach.
In this article, I will walk through three ways of illegitimately accessing the nodes of a Kubernetes cluster or a standalone Docker host. A successful attack of that nature, one that manages to reach the underlying node of a container, is high on the list of an attacker's main goals, and it all but delivers up the crown jewels. Accessing the nodes or hosts that containers run on potentially allows the attacker to exfiltrate data, steal security credentials, and possibly even and move laterally across a Kubernetes cluster.
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