Ensure that default service accounts are not actively used.

AltaNivel 1Automatizadaeks

Descripción

Default service accounts in EKS should not be used as the active identity for ordinary application or automation workloads. If a Pod does not specify a service account, Kubernetes automatically assigns the namespace default service account, and that account can authenticate to the Kubernetes API through its mounted token. Requires kubectl with cluster-wide read access (KUBECONFIG); system namespaces are excluded and listed resources must be remediated or documented as exceptions. Fails when a default service account does not set automountServiceAccountToken: false or is bound to a Role/ClusterRole.

Cómo se verifica

Método de auditoría: Comando de shell

shell

sa=$(kubectl get serviceaccounts -A -o go-template='{{range .items}}{{if eq .metadata.name "default"}}{{.metadata.namespace}} {{.automountServiceAccountToken}}{{"\n"}}{{end}}{{end}}') || exit 1
rb=$(kubectl get rolebindings,clusterrolebindings -A -o go-template='{{range .items}}{{$b:=.metadata.name}}{{$bn:=.metadata.namespace}}{{range .subjects}}{{if eq .kind "ServiceAccount"}}{{if eq .name "default"}}{{if .namespace}}{{.namespace}}{{else}}{{$bn}}{{end}} {{$b}}{{"\n"}}{{end}}{{end}}{{end}}{{end}}') || exit 1
bad=$(printf '%s\n' "$sa" | awk -v ex='^(kube-system|kube-public|kube-node-lease)$' 'NF && $1 !~ ex && $2!="false" {print "automount: " $1}')
bad2=$(printf '%s\n' "$rb" | awk -v ex='^(kube-system|kube-public|kube-node-lease)$' 'NF && $1 !~ ex {print "binding: " $0}')
if [ -z "$bad$bad2" ]; then echo compliant; else printf '%s\n%s\n' "$bad" "$bad2" | grep . | head -n 25; fi

Salida esperada: compliant

Cómo se corrige

Método de corrección: Guía o parche de infraestructura

Create dedicated service accounts for workloads that need Kubernetes API access, IRSA, or EKS Pod Identity, and update those workloads to explicitly set serviceAccountNam rather than relying on the namespace default service account. For workloads that do not need Kubernetes API access, disable service account token auto-mounting and avoid using the default service account as the active workload identity. Also review the default service account in each namespace and ensure it is not bound to unnecessary RBAC permissions.

Propiedades

Sistemas operativos: Cualquiera
Etiquetas: ekspoliciesrbac
Referencia: CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v2.0.0 - 4.1.5 Ensure that default service accounts are not actively used.

Verificar este host

Ejecute esto en un equipo que tenga permiso para auditar. El escaneo es de solo lectura.

shell

tmaegis scan --target eks