Kubernetes Security Audit

Perform comprehensive security audits of Kubernetes clusters, identifying vulnerabilities, misconfigurations, and compliance gaps.

Prerequisites

•kubectl configured with administrative access (kubeconfig in ~/.kube/config or specified via KUBECONFIG)
•Cluster admin or equivalent read permissions across all namespaces
•Python 3.8+ with pyyaml, tabulate dependencies (optional, for report generation)

Audit Workflow Overview

•Cluster Access Validation - Verify connectivity and permissions
•Cluster Information Gathering - Version, nodes, namespaces inventory
•RBAC Analysis - Roles, bindings, privilege escalation paths
•Pod Security Assessment - Container privileges, security contexts
•Network Policy Review - Ingress/egress rules, default deny policies
•Secrets Management Audit - Encryption, exposure risks
•Workload Configuration Review - Resource limits, probes, images
•CIS Benchmark Checks - Alignment with Kubernetes security benchmarks
•Report Generation - Findings with severity and remediation

Step 1: Cluster Access Validation

Verify kubectl connectivity and permissions before proceeding:

bash

# Test cluster connectivity
kubectl cluster-info

# Verify admin access
kubectl auth can-i '*' '*' --all-namespaces

# Check current context
kubectl config current-context

# List available contexts
kubectl config get-contexts

If kubectl auth can-i '*' '*' returns no, document limited permissions and adjust audit scope accordingly.

Step 2: Cluster Information Gathering

Collect cluster metadata for context:

bash

# Kubernetes version (check for EOL or vulnerable versions)
kubectl version --output=yaml

# Node inventory with roles
kubectl get nodes -o wide

# Namespace inventory
kubectl get namespaces

# API resources available
kubectl api-resources --verbs=list -o name

# Cluster events (last 100, look for security-relevant)
kubectl get events -A --sort-by='.lastTimestamp' | tail -100

Version Security Check

Compare against references/k8s_cve_versions.md for known vulnerabilities in the running version.

Step 3: RBAC Analysis

See references/rbac_analysis.md for detailed RBAC security patterns.

Extract RBAC Configuration

bash

# ClusterRoles (focus on high-privilege)
kubectl get clusterroles -o yaml > /tmp/clusterroles.yaml

# ClusterRoleBindings
kubectl get clusterrolebindings -o yaml > /tmp/clusterrolebindings.yaml

# Roles per namespace
kubectl get roles -A -o yaml > /tmp/roles.yaml

# RoleBindings per namespace
kubectl get rolebindings -A -o yaml > /tmp/rolebindings.yaml

# ServiceAccounts
kubectl get serviceaccounts -A -o yaml > /tmp/serviceaccounts.yaml

High-Risk RBAC Patterns to Flag

Risk	Pattern	Detection
Critical	Wildcard permissions (`*` on resources/verbs)	`grep -E "resources:.\\|verbs:.\"`
Critical	Secrets access cluster-wide	ClusterRole with `get/list secrets`
High	Pod exec permissions	Verb `create` on `pods/exec`
High	ServiceAccount token mounting	`automountServiceAccountToken: true`
High	Impersonation rights	Verb on `users`, `groups`, `serviceaccounts` impersonate
Medium	Excessive namespace admin	RoleBinding to `admin` or `edit` for broad groups

Quick RBAC Risk Detection

bash

# Find wildcard cluster permissions
kubectl get clusterroles -o json | jq -r '.items[] | select(.rules[]?.resources[]? == "*" or .rules[]?.verbs[]? == "*") | .metadata.name'

# Find who can exec into pods
kubectl auth can-i create pods/exec --all-namespaces --list

# Find who can read secrets cluster-wide
kubectl auth can-i get secrets --all-namespaces --list

# ServiceAccounts with cluster-admin binding
kubectl get clusterrolebindings -o json | jq -r '.items[] | select(.roleRef.name == "cluster-admin") | .subjects[]? | select(.kind == "ServiceAccount") | "\(.namespace)/\(.name)"'

Step 4: Pod Security Assessment

Gather Pod Security Contexts

bash

# All pods with security context details
kubectl get pods -A -o json | jq -r '
  .items[] | 
  "\(.metadata.namespace)/\(.metadata.name): privileged=\(.spec.containers[].securityContext.privileged // false), runAsRoot=\(.spec.containers[].securityContext.runAsNonRoot // "unset"), hostNetwork=\(.spec.hostNetwork // false), hostPID=\(.spec.hostPID // false)"
'

Critical Security Flags

Flag	Risk	Query
`privileged: true`	Critical - Full host access	`kubectl get pods -A -o json \| jq '.items[] \| select(.spec.containers[].securityContext.privileged == true)'`
`hostNetwork: true`	High - Network namespace escape	`kubectl get pods -A -o json \| jq '.items[] \| select(.spec.hostNetwork == true)'`
`hostPID: true`	High - Process namespace escape	`kubectl get pods -A -o json \| jq '.items[] \| select(.spec.hostPID == true)'`
`hostPath` volumes	High - Host filesystem access	`kubectl get pods -A -o json \| jq '.items[] \| select(.spec.volumes[]?.hostPath != null)'`
`runAsUser: 0`	Medium - Container runs as root	Check `securityContext.runAsUser`
Missing `readOnlyRootFilesystem`	Low - Writable container filesystem	Default is writable

Pod Security Standards Compliance

Check namespace labels for Pod Security Standards enforcement:

bash

# Check PSS labels on namespaces
kubectl get namespaces -o json | jq -r '.items[] | "\(.metadata.name): enforce=\(.metadata.labels["pod-security.kubernetes.io/enforce"] // "none"), audit=\(.metadata.labels["pod-security.kubernetes.io/audit"] // "none")"'

Expected: Production namespaces should have restricted or baseline enforcement.

Step 5: Network Policy Review

See references/network_policy_analysis.md for network security patterns.

Inventory Network Policies

bash

# All NetworkPolicies
kubectl get networkpolicies -A -o yaml > /tmp/netpols.yaml

# Namespaces without any NetworkPolicy
kubectl get namespaces -o name | while read ns; do
  ns_name=${ns#namespace/}
  count=$(kubectl get networkpolicies -n "$ns_name" --no-headers 2>/dev/null | wc -l)
  if [ "$count" -eq 0 ]; then
    echo "No NetworkPolicy: $ns_name"
  fi
done

Network Security Checklist

• Default deny ingress policy exists in production namespaces
• Default deny egress policy exists (prevents data exfiltration)
• Policies use specific podSelectors (not empty {})
• Egress to metadata API (169.254.169.254) is blocked
• Cross-namespace communication is explicitly allowed only where needed

Default Deny Policy Template

Namespaces lacking this pattern are exposed:

yaml

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny-all
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  - Egress

Step 6: Secrets Management Audit

Secrets Inventory

bash

# Count secrets by namespace and type
kubectl get secrets -A -o json | jq -r '.items | group_by(.metadata.namespace) | .[] | "\(.[0].metadata.namespace): \(length) secrets"'

# Identify secret types
kubectl get secrets -A -o json | jq -r '.items | group_by(.type) | .[] | "\(.[0].type): \(length)"'

# Find secrets mounted in pods
kubectl get pods -A -o json | jq -r '.items[] | .spec.volumes[]? | select(.secret != null) | .secret.secretName' | sort -u

Secrets Security Checklist

• Encryption at rest enabled (kubectl get apiservices v1 -o yaml - check for EncryptionConfiguration)
• No secrets in environment variables (prefer volume mounts)
• External secrets manager integration (e.g., Vault, AWS Secrets Manager, External Secrets Operator)
• Secrets not stored in ConfigMaps
• RBAC restricts secret access appropriately

Check for Secrets in ConfigMaps (Anti-pattern)

bash

# Look for base64-encoded or password-like values in ConfigMaps
kubectl get configmaps -A -o json | jq -r '.items[] | select(.data != null) | select(.data | to_entries[] | .key | test("password|secret|key|token|credential"; "i")) | "\(.metadata.namespace)/\(.metadata.name)"'

Step 7: Workload Configuration Review

Image Security

bash

# List all container images
kubectl get pods -A -o json | jq -r '.items[].spec.containers[].image' | sort -u

# Find images without explicit tags (using :latest or no tag)
kubectl get pods -A -o json | jq -r '.items[].spec.containers[] | select(.image | test(":latest$") or (test(":") | not)) | .image' | sort -u

# Find images from untrusted registries
kubectl get pods -A -o json | jq -r '.items[].spec.containers[].image' | grep -vE "^(gcr.io|docker.io|quay.io|registry.k8s.io|your-registry.com)" | sort -u

Resource Limits Check

bash

# Pods without resource limits
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[] | .resources.limits == null) | "\(.metadata.namespace)/\(.metadata.name)"'

# Pods without resource requests
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[] | .resources.requests == null) | "\(.metadata.namespace)/\(.metadata.name)"'

Liveness/Readiness Probes

bash

# Pods without health probes
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[] | (.livenessProbe == null) and (.readinessProbe == null)) | "\(.metadata.namespace)/\(.metadata.name)"'

Step 8: CIS Benchmark Quick Checks

See references/cis_benchmarks.md for complete CIS Kubernetes Benchmark mapping.

Control Plane Security (if accessible)

bash

# Check API server flags (if running as pod)
kubectl get pods -n kube-system -l component=kube-apiserver -o yaml | grep -E "anonymous-auth|enable-admission-plugins|audit-log"

# Check etcd encryption
kubectl get pods -n kube-system -l component=etcd -o yaml | grep -E "client-cert-auth|peer-client-cert-auth"

Worker Node Security

bash

# Kubelet configuration (requires node access or kubelet API)
# Check for --anonymous-auth=false, --authorization-mode not AlwaysAllow
kubectl get nodes -o json | jq -r '.items[].status.nodeInfo'

Step 9: Generate Audit Report

Use scripts/generate_report.py to compile findings:

bash

python scripts/generate_report.py --kubeconfig ~/.kube/config --output audit_report.md

Report Structure

markdown

# Kubernetes Security Audit Report

**Cluster**: {context_name}
**Date**: {timestamp}
**Auditor**: Claude AI

## Executive Summary

| Category | Critical | High | Medium | Low |
|----------|----------|------|--------|-----|
| RBAC | X | X | X | X |
| Pod Security | X | X | X | X |
| Network | X | X | X | X |
| Secrets | X | X | X | X |
| Workloads | X | X | X | X |

**Overall Risk Level**: {Critical/High/Medium/Low}

## Cluster Information
- Kubernetes Version: {version}
- Nodes: {count}
- Namespaces: {count}

## Critical Findings
{findings with remediation}

## High-Risk Findings
{findings with remediation}

## Detailed Findings by Category

### RBAC Analysis
{detailed findings}

### Pod Security
{detailed findings}

### Network Policies
{detailed findings}

### Secrets Management
{detailed findings}

### Workload Configuration
{detailed findings}

## Remediation Priority Matrix
{ordered list by risk and effort}

## Appendix
- Raw data references
- Commands used

Quick Audit Commands

Run this script for a rapid security snapshot:

bash

#!/bin/bash
echo "=== K8s Security Quick Audit ==="

echo -e "\n[1] Privileged Pods:"
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[].securityContext.privileged == true) | "\(.metadata.namespace)/\(.metadata.name)"'

echo -e "\n[2] Pods with hostNetwork/hostPID:"
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.hostNetwork == true or .spec.hostPID == true) | "\(.metadata.namespace)/\(.metadata.name)"'

echo -e "\n[3] Cluster-admin ServiceAccounts:"
kubectl get clusterrolebindings -o json | jq -r '.items[] | select(.roleRef.name == "cluster-admin") | .subjects[]? | "\(.kind): \(.namespace // "cluster")/\(.name)"'

echo -e "\n[4] Namespaces without NetworkPolicies:"
for ns in $(kubectl get ns -o jsonpath='{.items[*].metadata.name}'); do
  [ $(kubectl get netpol -n $ns --no-headers 2>/dev/null | wc -l) -eq 0 ] && echo "$ns"
done

echo -e "\n[5] Pods with latest/untagged images:"
kubectl get pods -A -o json | jq -r '.items[].spec.containers[] | select(.image | test(":latest$") or (test(":") | not)) | .image' | sort -u

echo -e "\n[6] Pods without resource limits:"
kubectl get pods -A -o json | jq -r '.items[] | select(.spec.containers[] | .resources.limits == null) | "\(.metadata.namespace)/\(.metadata.name)"' | head -20

Reference Files

•references/rbac_analysis.md: Deep-dive RBAC security patterns and privilege escalation paths
•references/network_policy_analysis.md: Network policy security patterns and templates
•references/cis_benchmarks.md: CIS Kubernetes Benchmark controls mapping
•references/k8s_cve_versions.md: Known CVEs by Kubernetes version

Report Template

Use assets/audit_report_template.md for consistent report formatting.

Common Remediation Patterns

Finding	Remediation
Privileged pods	Add `securityContext.privileged: false`, use capabilities instead
Missing NetworkPolicies	Apply default-deny, then allow required traffic
Overly permissive RBAC	Follow least-privilege, use namespaced Roles
Secrets in env vars	Mount as volumes with `defaultMode: 0400`
Latest image tags	Pin to specific digests or semantic versions
Missing resource limits	Define CPU/memory limits and requests
No Pod Security Standards	Add `pod-security.kubernetes.io/*` labels to namespaces