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Impact & Risk Analysis

  • Severity: High
  • CIS Benchmark: CIS 5.2.2
  • Impact: Full Host Compromise. Privileged containers have access to all Linux Kernel capabilities and devices. A container running with privileged: true effectively bypasses container isolation, allowing it to do almost everything the host can do (e.g., loading kernel modules, accessing host hardware, modifying host files).

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Common Misconfiguration

Developers often set privileged: true to bypass permission errors quickly (e.g., for Docker-in-Docker builds or hardware access) without realizing it grants root-level access to the underlying node.

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Vulnerable Example

# Vulnerable Pod Spec
apiVersion: v1
kind: Pod
metadata:
  name: privileged-pod
spec:
  containers:
  - name: app
    image: nginx
    securityContext:
      # VULNERABLE: Grants full host access
      privileged: true

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Secure Example

# Secure Pod Spec
apiVersion: v1
kind: Pod
metadata:
  name: secure-pod
spec:
  containers:
  - name: app
    image: nginx
    securityContext:
      # SECURE: Explicitly disabled (default is false, but good to be explicit)
      privileged: false
      # BEST PRACTICE: Also prevent escalation
      allowPrivilegeEscalation: false

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Audit Procedure

Run the following command to inventory all privileged usage on the cluster: 
kubectl get pods -A -o=jsonpath=$'{range .items[*]}{@.metadata.name}: {@..securityContext}\n{end}'
  • Analyze: The output shows the security context for every pod.
  • Fail: If you see {"privileged":true} in the output for any non-system pod (like calico-node or kube-proxy, which may legitimately require it).

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Remediation

Add policies to each namespace in the cluster to restrict the admission of privileged containers. Using Pod Security Admission (Native K8s): Apply the baseline or restricted profile to your namespaces. The baseline profile forbids privileged containers. 
# Enforce the baseline policy on the 'default' namespace
kubectl label --overwrite ns default pod-security.kubernetes.io/enforce=baseline
Using Policy Engines (OPA Gatekeeper / Kyverno): Deploy a ConstraintTemplate or ClusterPolicy that specifically blocks securityContext.privileged: true.