Minimize the admission of containers wishing to share the host process ID namespace (PSP)

Do not generally permit containers to be run with the hostPID flag set to true. A container running in the host's PID namespace can inspect processes running outside the container. If the container also has access to ptrace capabilities this can be used to escalate privileges outside of the container. There should be at least one CloudGuard Admission Control (CAC) rule or PodSecurityPolicy (PSP) defined which does not permit containers to share the host PID namespace. If you need to run containers which require hostPID, this should be defined in a separate CAC or PSP and you should carefully check RBAC controls to ensure that only limited service accounts and users are given permission to access that CAC or PSP.

Risk Level: High
Cloud Entity: Pod Security Policies
CloudGuard Rule ID: D9.K8S.IAM.24
Covered by Spectral: Yes
Category: Security, Identity, & Compliance

GSL LOGIC

List<KubernetesPodSecurityPolicy> where items length() > 0 should have items contain [spec.hostPID != 'true']

REMEDIATION

Create a CAC or PSP as described in the Kubernetes documentation, ensuring that the .spec.hostPID field is omitted or set to false.

References

  1. https://kubernetes.io/docs/concepts/policy/pod-security-policy

Pod Security Policies

A Pod Security Policy is a cluster-level resource that controls security sensitive aspects of the pod specification. The PodSecurityPolicy objects define a set of conditions that a pod must run with in order to be accepted into the system, as well as defaults for the related fields.

Compliance Frameworks

  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.0.1
  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.1.0
  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.2.0
  • CIS Amazon Elastic Kubernetes Service (EKS) Benchmark v1.3.0
  • CIS Google Kubernetes Engine (GKE) Benchmark v1.2.0
  • CIS Google Kubernetes Engine (GKE) Benchmark v1.4.0
  • CIS Kubernetes Benchmark v1.20
  • CIS Kubernetes Benchmark v1.23
  • CIS Kubernetes Benchmark v1.5.1
  • CIS Kubernetes Benchmark v1.6.1
  • CIS Microsoft Kubernetes Engine (AKS) Benchmark v1.1.0
  • CIS Microsoft Kubernetes Engine (AKS) Benchmark v1.3.0
  • Kubernetes NIST.SP.800-190
  • Kubernetes v.1.13 CloudGuard Best Practices
  • Kubernetes v.1.14 CloudGuard Best Practices