Using Kubectl to Create a Scheduled Task in a Kubernetes Cluster Container

Environment Description

Environment Setup

Install kubectl

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
chmod +x ./kubectl
mv kubectl /usr/bin/kubectl

Create a Scheduled Task

• An attacker can use a Kubernetes CronJob to schedule the execution of malicious code, which will run as a container in the cluster.

• Create a scheduled task:

kubectl create -f cronjob.yaml -n default # 在默认namespace下创建定时任务

• The contents of cronjob.yaml are as follows:

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: art
spec:
  schedule: "*/1 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: hello
            image: busybox:stable
            imagePullPolicy: IfNotPresent
            command:
            - /bin/sh
            - -c
            - date; echo Hello Test Cronjob
          restartPolicy: OnFailure

• View the scheduled task just created in the default namespace:

kubectl get cronjob -n default