Cis Oke V150 4.1.4

4.1.4 Minimize access to create pods (Automated)

Profile Applicability

• Level 1

Description

The ability to create pods in a namespace can provide a number of opportunities for privilege escalation, such as assigning privileged service accounts to these pods or mounting hostPaths with access to sensitive data (unless Pod Security Policies are implemented to restrict this access).

As such, access to create new pods should be restricted to the smallest possible group of users.

Rationale

The ability to create pods in a cluster opens up possibilities for privilege escalation and should be restricted, where possible.

Impact

Care should be taken not to remove access to pods to system components which require this for their operation.

Audit Procedure

Review the users who have create access to pod objects in the Kubernetes API. Run the following command to list all the users who have access to create pod objects in the Kubernetes API:

kubectl auth can-i create pods --all-namespaces --as=system:authenticated

This command checks if the system:authenticated group (which includes all authenticated users) has the create permission for pod objects in all namespaces. The output will display either yes or no for each user.

Note: If you want to check for specific namespaces, replace --all-namespaces with the desired namespace(s) separated by commas.

Remediation

Where possible, remove create access to pod objects in the cluster.

Default Value

By default, the following list of principals have create privileges on pod objects:

CLUSTERROLEBINDING                                          SUBJECT
TYPE              SA-NAMESPACE
cluster-admin                                               system:masters
Group
system:controller:clusterrole-aggregation-controller        clusterrole-
aggregation-controller  ServiceAccount  kube-system
system:controller:daemon-set-controller                     daemon-set-controller
ServiceAccount    kube-system
system:controller:job-controller                            job-controller
ServiceAccount    kube-system
system:controller:persistent-volume-binder                  persistent-volume-
binder                 ServiceAccount  kube-system
system:controller:replicaset-controller                     replicaset-controller
ServiceAccount    kube-system
system:controller:replication-controller                    replication-controller
ServiceAccount    kube-system
system:controller:statefulset-controller                    statefulset-controller
ServiceAccount    kube-system

CIS Controls

MITRE ATT&CK Mappings

Profile: Level 1