Ensure that the admission control plugin AlwaysPullImages is set (API Server)
Always pull images. Setting admission control policy to AlwaysPullImages forces every new pod to pull the required images every time. In a multi-tenant cluster users can be assured that their private images can only be used by those who have the credentials to pull them. Without this admission control policy, once an image has been pulled to a node, any pod from any user can use it simply by knowing the image s name, without any authorization check against the image ownership. When this plug-in is enabled, images are always pulled prior to starting containers, which means valid credentials are required.
Risk Level: Medium
Cloud Entity: Pods
CloudGuard Rule ID: D9.K8S.NET.10
Covered by Spectral: Yes
Category: Compute
GSL LOGIC
KubernetesPod where labels contain [value='kube-apiserver'] and namespace = 'kube-system' should have spec.containers with [parsedArgs contain [key like 'enable-admission-plugins' and value like '%AlwaysPullImages%']]
REMEDIATION
Edit the API server pod specification file $apiserverconf
on the master node and set the --enable-admission-plugins to
include AlwaysPullImages.
--enable-admission-plugins=...,AlwaysPullImages,...
References
- https://kubernetes.io/docs/admin/kube-apiserver/
- https://kubernetes.io/docs/admin/admission-controllers/#alwayspullimages
Pods
Pods are the smallest deployable units of computing that can be created and managed in Kubernetes.A Pod is a group of one or more containers (such as Docker containers), with shared storage/network, and a specification for how to run the containers.
Compliance Frameworks
- CIS Kubernetes Benchmark v1.20
- CIS Kubernetes Benchmark v1.23
- CIS Kubernetes Benchmark v1.24
- CIS Kubernetes Benchmark v1.4.0
- CIS Kubernetes Benchmark v1.5.1
- CIS Kubernetes Benchmark v1.6.1
- Kubernetes NIST.SP.800-190
- Kubernetes v.1.13 CloudGuard Best Practices
- Kubernetes v.1.14 CloudGuard Best Practices
Updated about 1 year ago