KubernetesOverview
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.
Remediation guidance
Where possible, remove create access to pod objects in the cluster.
References
-
https://workbench.cisecurity.org/sections/1126661/recommendations/1838592
-
https://kubernetes.io/docs/reference/access-authn-authz/rbac/
Service-wide remediation
Recommended when many resources are affected: fix the platform baseline first so new resources inherit the secure setting, then remediate the existing flagged resources in batches.
Kubernetes
Use admission policies, baseline cluster configuration, GitOps templates, and namespace or workload guardrails so new deployments follow the control by default.
Operational rollout
- Fix the baseline first at the account, subscription, project, cluster, or tenant scope that owns this control.
- Remediate the currently affected resources in batches, starting with internet-exposed and production assets.
- Re-scan and track approved exceptions with an owner and expiry date.
Query logic
These are the stored checks tied to this control.
Kubernetes RoleBindings to Roles that can create pods
Connectors
Covered asset types
Expected check: eq []
{
roles(
where: {
AND: [
{
rules_SOME: {
AND: [
{
OR: [
{ verbs_INCLUDES: "create" }
{ verbs_INCLUDES: "*" }
]
}
{
OR: [
{ resources_INCLUDES: "pods" }
{ resources_INCLUDES: "*" }
]
}
{ OR: [{ apiGroup_INCLUDES: "" }, { apiGroup_INCLUDES: "*" }] }
]
}
},
{bindings_SOME: {idFromProvider_NOT: ""}}
]
}
) {
bindings {
...AssetFragment
}
}
}
Kubernetes RoleBindings to ClusterRoles that can create pods
Connectors
Covered asset types
Expected check: eq []
{
clusterRoles(
where: {
AND: [
{
rules_SOME: {
AND: [
{
OR: [
{ verbs_INCLUDES: "create" }
{ verbs_INCLUDES: "*" }
]
}
{
OR: [
{ resources_INCLUDES: "pods" }
{ resources_INCLUDES: "*" }
]
}
{ OR: [{ apiGroup_INCLUDES: "" }, { apiGroup_INCLUDES: "*" }] }
]
}
},
{roleBindings_SOME: {idFromProvider_NOT: ""}}
]
}
) {
roleBindings {
...AssetFragment
}
}
}
Kubernetes RoleBindings to ClusterRoles that can create pods
Connectors
Covered asset types
Expected check: eq []
{
clusterRoles(
where: {
AND: [
{
rules_SOME: {
AND: [
{
OR: [
{ verbs_INCLUDES: "create" }
{ verbs_INCLUDES: "*" }
]
}
{
OR: [
{ resources_INCLUDES: "pods" }
{ resources_INCLUDES: "*" }
]
}
{ OR: [{ apiGroup_INCLUDES: "" }, { apiGroup_INCLUDES: "*" }] }
]
}
},
{clusterRoleBindings_SOME: {idFromProvider_NOT: ""}}
]
}
) {
clusterRoleBindings {
...AssetFragment
}
}
}
