ephemeralcontainer-run-as-nonroot
With runAsNonRoot unset, the kubelet never rejects an image whose user is UID 0, so the ephemeral debug container silently runs as root and any compromise gains root file ownership and the full capability set.
!has(object.spec.ephemeralContainers) || object.spec.ephemeralContainers.all(ec,
variables.podNonRootTrue
? (!has(ec.securityContext) || !has(ec.securityContext.runAsNonRoot) || ec.securityContext.runAsNonRoot == true)
: (has(ec.securityContext) && has(ec.securityContext.runAsNonRoot) && ec.securityContext.runAsNonRoot == true)
)
spec.ephemeralContainers[*].securityContext.runAsNonRoot must be set to true, unless the Pod-level spec.securityContext.runAsNonRoot is true—in which case it may be undefined or true.
podNonRootTrue
has(object.spec.securityContext) && has(object.spec.securityContext.runAsNonRoot) && object.spec.securityContext.runAsNonRoot == true
Set runAsNonRoot to true on every ephemeral container, or set it once at pod level and let the ephemeral containers inherit it. Fields: spec.ephemeralContainers[*].securityContext.runAsNonRoot, spec.securityContext.runAsNonRoot.
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicy
metadata:
name: ephemeralcontainer-run-as-nonroot
annotations:
kubeapt.io/uuid: "d2ea2b6d-4d47-4d65-9581-2db116e96f7b"
security.kubeapt.io/displayName: "May Run as Root"
security.kubeapt.io/description: "With runAsNonRoot unset, the kubelet never rejects an image whose user is UID 0, so the ephemeral debug container silently runs as root and any compromise gains root file ownership and the full capability set."
security.kubeapt.io/resource: "EphemeralContainers"
security.kubeapt.io/severity: "Moderate"
security.kubeapt.io/remediation: "Set runAsNonRoot to true on every ephemeral container, or set it once at pod level and let the ephemeral containers inherit it. Fields: spec.ephemeralContainers[*].securityContext.runAsNonRoot, spec.securityContext.runAsNonRoot."
security.kubeapt.io/product: "Kubernetes"
spec:
failurePolicy: Fail
matchConstraints:
resourceRules:
- apiGroups:
- ''
apiVersions:
- v1
operations:
- CREATE
- UPDATE
resources:
- pods/ephemeralcontainers
variables:
- name: podNonRootTrue
expression: |
has(object.spec.securityContext) && has(object.spec.securityContext.runAsNonRoot) && object.spec.securityContext.runAsNonRoot == true
validations:
- expression: |
!has(object.spec.ephemeralContainers) || object.spec.ephemeralContainers.all(ec,
variables.podNonRootTrue
? (!has(ec.securityContext) || !has(ec.securityContext.runAsNonRoot) || ec.securityContext.runAsNonRoot == true)
: (has(ec.securityContext) && has(ec.securityContext.runAsNonRoot) && ec.securityContext.runAsNonRoot == true)
)
message: "spec.ephemeralContainers[*].securityContext.runAsNonRoot must be set to true, unless the Pod-level spec.securityContext.runAsNonRoot is true\u2014in which case it may be undefined or true.\n"Save it as ephemeralcontainer-run-as-nonroot.yaml — the commands below assume that name.
Check a workload against this one policy, before anything is installed on a cluster.
$ kubeapt validate -p ./ephemeralcontainer-run-as-nonroot.yaml -r ./workload.yamlOr without the file, from the published policy set — -r takes a directory too:
$ kubeapt policies download && kubeapt validate --policy-name ephemeralcontainer-run-as-nonroot -r ./manifestsOr against every namespace in the cluster your kubeconfig points at:
$ kubeapt validate --policy-name ephemeralcontainer-run-as-nonroot -A