Privileged containers are admitted misconfiguration detected in code

Rule Details

Cortex AppSec Rule ID	APPSEC_K8S_2
Category - Subcategory	Kubernetes - Access Control
Provider	OTHER
Severity	HIGH
Framework	Helm, Kubernetes, Kustomize, Terraform, Terraform Plan

Impact

Privileged containers are containers that have all of the root capabilities of a host machine, allowing access to resources that are not accessible in ordinary containers. Running a container with a privileged flag allows users to have critical access to the host's resources. If a privileged container is compromised, it does not necessarily entail remote code execution, but it implies that an attacker will be able to run full host root with all of the available capabilities, including CAP_SYS_ADMIN. Common uses of privileged containers include: running a Docker daemon inside a Docker container, running a container with direct hardware access, and automating CI/CD tasks in the open-source automation server Jenkins.

How to Fix

Resource: PodSecurityPolicy

• Arguments: privileged (Optional) When set to false, containers are unable to run processes that are essentially equivalent to root on the host.

To use a PodSecurityPolicy resource, the requesting user or target pod's service account must be authorized to use the policy. The preferred method is to grant access to the service account.

In the following example we use RBAC, a standard Kubernetes authorization mode.

A Role or ClusterRole must grant access to use the desired policies.

Kind: ClusterRole

The ClusterRole is then bound to the authorized service(s):

Kind: ClusterRoleBinding [source,go]

apiVersion: policy/v1beta1 kind: PodSecurityPolicy metadata: name: spec:

• privileged: false

---

apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: rules:

• apiGroups: ['policy'] resources: ['podsecuritypolicies'] verbs: ['use'] resourceNames:

---

apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: roleRef: kind: ClusterRole name: apiGroup: rbac.authorization.k8s.io subjects:

• kind: ServiceAccount name: namespace:

---