Kubelet Protect Kernel Defaults Set To False

  • Query id: 6cf42c97-facd-4fda-b8af-ea4529123355
  • Query name: Kubelet Protect Kernel Defaults Set To False
  • Platform: Kubernetes
  • Severity: Medium
  • Category: Insecure Configurations
  • URL: Github

Description

--protect-kernel-defaults should be set to true
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: foo/bar
      command: ["kubelet"]
      args: ["--protect-kernel-defaults=false"]
  restartPolicy: OnFailure
Positive test num. 2 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: foo/bar
      command: ["kubelet","--protect-kernel-defaults=false"]
      args: []
  restartPolicy: OnFailure
Positive test num. 3 - yaml file
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
address: "192.168.0.8"
port: 20250
protectKernelDefaults: false
serializeImagePulls: false
tlsCertFile: "someFile.txt"
tlsPrivateKeyFile: "someFile.txt"
evictionHard:
    memory.available:  "200Mi"

Positive test num. 4 - yaml file 
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
address: "192.168.0.8"
port: 20250
serializeImagePulls: false
tlsCertFile: "someFile.txt"
tlsPrivateKeyFile: "someFile.txt"
evictionHard:
    memory.available:  "200Mi"

Code samples without security vulnerabilities

Negative test num. 1 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: foo/bar
      command: ["kubelet"]
      args: ["--protect-kernel-defaults=true"]
  restartPolicy: OnFailure
Negative test num. 2 - yaml file
apiVersion: v1
kind: Pod
metadata:
  name: command-demo
  labels:
    purpose: demonstrate-command
spec:
  containers:
    - name: command-demo-container
      image: foo/bar
      command: ["kubelet"]
      args: []
  restartPolicy: OnFailure
Negative test num. 3 - yaml file
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
address: "192.168.0.8"
port: 20250
serializeImagePulls: false
protectKernelDefaults: true
tlsCertFile: "someFile.txt"
tlsPrivateKeyFile: "someFile.txt"
evictionHard:
    memory.available:  "200Mi"

Negative test num. 4 - json file 
{
    "kind": "KubeletConfiguration",
    "apiVersion": "kubelet.config.k8s.io/v1beta1",
    "port": 10250,
    "readOnlyPort": 10255,
    "cgroupDriver": "cgroupfs",
    "protectKernelDefaults": true,
    "hairpinMode": "promiscuous-bridge",
    "serializeImagePulls": false,
    "featureGates": {
      "RotateKubeletClientCertificate": true,
      "RotateKubeletServerCertificate": true
    }
  }