Pods with read-only root filesystem

ID: k8s-readonly-rootfs

Severity: medium

Author: princechaddha

Tags: cloud,devops,kubernetes,devsecops,pods,k8s,k8s-cluster-security

Description

Checks for pods and containers running with a read-only root filesystem to prevent modifications to the filesystem, enhancing security.

YAML Source

id: k8s-readonly-rootfs

info:
  name: Pods with read-only root filesystem
  author: princechaddha
  severity: medium
  description: Checks for pods and containers running with a read-only root filesystem to prevent modifications to the filesystem, enhancing security.
  impact: |
    Running containers with a read-only root filesystem ensures that applications are not able to write to the filesystem or modify existing content. This is a common security practice to prevent malicious changes.
  remediation: |
    Configure all pods and containers to have their root filesystem set to read-only mode. This can be achieved by setting the securityContext.readOnlyRootFilesystem parameter to true in the pod or container configuration.
  reference:
    - https://kubernetes.io/docs/concepts/policy/pod-security-policy/#volumes-and-file-systems
  tags: cloud,devops,kubernetes,devsecops,pods,k8s,k8s-cluster-security

flow: |
  code(1);
  for (let pod of template.items) {
    set("pod", pod)
    javascript(1);
  }

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: kubectl get pods --all-namespaces --output=json
    extractors:
      - type: json
        name: items
        internal: true
        json:
          - '.items[] | {pod: .metadata.name, containers: .spec.containers}'

javascript:
  - code: |
        let podData = JSON.parse(template.pod);
        podData.containers.forEach(container => {
          if (container.securityContext && container.securityContext.readOnlyRootFilesystem !== true) {
            let result = (`Container '${container.name}' in pod '${podData.pod}' is not running with a read-only root filesystem.`);
            Export(result);
          }
        });

    extractors:
      - type: dsl
        dsl:
          - response
# digest: 4a0a00473045022100a7b48676a224172a58389ab7a0e3bfab88d82412b94a449b2f4568848ef7d6f20220660e303dd733119023821c2a1059a03fc9fb6e01220f066d8217a868e5cf9c64:922c64590222798bb761d5b6d8e72950

Guide to check the vulnerabilities

This template is used to detect vulnerabilities in web applications. It can be used with the Nuclei tool to scan for specific patterns or behaviors.

$ nuclei -u "URL" -t "cloud/kubernetes/pods/k8s-readonly-rootfs.yaml"

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