Minimize the admission of containers with the NET_RAW capability (PSP)

Do not generally permit containers with the potentially dangerous NET_RAW capability. Containers run with a default set of capabilities as assigned by the Container Runtime. By default this can include potentially dangerous capabilities. With Docker as the container runtime the NET_RAW capability is enabled which may be misused by malicious containers. Ideally, all containers should drop this capability. There should be at least one CloudGuard Admission Control (CAC) rule or PodSecurityPolicy (PSP) defined which prevents containers with the NET_RAW capability from launching. If you need to run containers with this capability, 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.30
Covered by Spectral: Yes
Category: Security, Identity, & Compliance

GSL LOGIC

List<KubernetesPodSecurityPolicy> where items length() > 0 should have items contain [spec.requiredDropCapabilities contain ['NET_RAW' or 'ALL']]

REMEDIATION

CAC rule or PSP as described in the Kubernetes documentation, ensuring that the .spec.requiredDropCapabilities is set to include either NET_RAW or ALL.

References

  1. https://kubernetes.io/docs/concepts/policy/pod-security-policy/#enabling-pod-security-policies
  2. https://www.nccgroup.trust/uk/our-research/abusing-privileged-and-unprivileged-linux-containers/

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 Google Kubernetes Engine (GKE) Benchmark v1.2.0
  • 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
  • Kubernetes NIST.SP.800-190
  • Kubernetes v.1.13 CloudGuard Best Practices
  • Kubernetes v.1.14 CloudGuard Best Practices