Service Account Token Automount Not Disabled

• Query id: 48471392-d4d0-47c0-b135-cdec95eb3eef
• Query name: Service Account Token Automount Not Disabled
• Platform: Kubernetes
• Severity: Medium
• Category: Insecure Defaults
• URL: Github

Description

Service Account Tokens are automatically mounted even if not necessary
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

apiVersion: v1
kind: Pod
metadata:
  name: security-context-demo
spec:
  securityContext:
    runAsUser: 1000
    runAsGroup: 3000
    fsGroup: 2000
  volumes:
    - name: sec-ctx-vol
      emptyDir: { }
  containers:
    - name: sec-ctx-demo
      image: busybox
      command: [ "sh", "-c", "sleep 1h" ]
      volumeMounts:
        - name: sec-ctx-vol
          mountPath: /data/demo
      securityContext:
        allowPrivilegeEscalation: false
---
apiVersion: v1
kind: Pod
metadata:
  name: security.context.demo
spec:
  automountServiceAccountToken: true
  securityContext:
    runAsUser: 1000
    runAsGroup: 3000
    fsGroup: 2000
  volumes:
    - name: sec-ctx-vol
      emptyDir: { }
  containers:
    - name: sec-ctx-demo
      image: busybox
      command: [ "sh", "-c", "sleep 1h" ]
      volumeMounts:
        - name: sec-ctx-vol
          mountPath: /data/demo
      securityContext:
        allowPrivilegeEscalation: false
---
apiVersion: serving.knative.dev/v1
kind: Configuration
metadata:
  name: dummy-config
  namespace: knative-sequence
spec:
  template:
    spec:
      automountServiceAccountToken: true
      securityContext:
        runAsUser: 1000
        runAsGroup: 3000
        fsGroup: 2000
      volumes:
        - name: sec-ctx-vol
          emptyDir: { }
      containers:
        - name: sec-ctx-demo
          image: busybox
          command: [ "sh", "-c", "sleep 1h" ]
          volumeMounts:
            - name: sec-ctx-vol
              mountPath: /data/demo
          securityContext:
            allowPrivilegeEscalation: false        

Positive test num. 2 - yaml file

apiVersion: v1
kind: ServiceAccount
metadata:
  name: redistest-sa
automountServiceAccountToken: true
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: demoenv
  labels:
    app: redis
spec:
  selector:
    matchLabels:
      app: redis
  template:
    metadata:      
      labels:
        app: redis
    spec:
      serviceAccountName: redistest-sa
      containers:
      - name: redis
        image: redis:latest

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

apiVersion: v1
kind: Pod
metadata:
  name: security-context-demo
spec:
  automountServiceAccountToken: false
  securityContext:
    runAsUser: 1000
    runAsGroup: 3000
    fsGroup: 2000
  volumes:
    - name: sec-ctx-vol
      emptyDir: { }
  containers:
    - name: sec-ctx-demo
      image: busybox
      command: [ "sh", "-c", "sleep 1h" ]
      volumeMounts:
        - name: sec-ctx-vol
          mountPath: /data/demo
      securityContext:
        allowPrivilegeEscalation: false

Negative test num. 2 - yaml file

apiVersion: v1
kind: ServiceAccount
metadata:
  name: redistest-sa
automountServiceAccountToken: false
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: demoenv
  labels:
    app: redis
spec:
  selector:
    matchLabels:
      app: redis
  template:
    metadata:      
      labels:
        app: redis
    spec:
      serviceAccountName: redistest-sa
      containers:
      - name: redis
        image: redis:latest