Benchmarking Kubernetes with kube-bench

Overview

kube-bench (by Aqua Security) is an open-source tool that checks whether a Kubernetes cluster is deployed securely by running the checks documented in the CIS Kubernetes Benchmark. It inspects the control-plane components (API server, controller manager, scheduler, etcd), the kubelet and worker-node configuration, and cluster-wide policy settings, then reports each check as PASS, FAIL, WARN, or INFO with a remediation recommendation drawn directly from the CIS guidance. Tests are configuration-driven YAML files, so kube-bench tracks new Kubernetes versions and benchmark revisions and supports managed distributions (EKS, GKE, AKS, ACK, OpenShift, RKE, k3s).

Hardening a cluster against the CIS Benchmark directly reduces the attack surface for T1610 (Deploy Container), where an adversary deploys a container to execute code or evade defenses — for example by abusing privileged containers, host namespaces, anonymous API access, or insecure kubelet settings that an unhardened cluster leaves exposed.

kube-bench can run as a standalone binary on a node, inside a container, or — most commonly — as a Kubernetes Job whose pod has the host filesystem mounted so it can read the relevant config files. Output is available as human-readable text, JSON, JUnit, or AWS Security Finding Format (ASFF) and can be pushed to a PostgreSQL database for trend tracking.

When to Use

• When establishing a security baseline for a new Kubernetes cluster against the CIS Kubernetes Benchmark.
• When performing periodic compliance audits of control-plane and node hardening.
• When validating remediation after applying hardening changes (re-run to confirm checks now PASS).
• When integrating cluster compliance scanning into CI/CD or a continuous monitoring pipeline.
• When preparing evidence for SOC 2, PCI DSS, or internal hardening compliance.

Prerequisites

• Access to the cluster: either SSH access to a control-plane/worker node (binary mode) or kubectl with permission to create Jobs (in-cluster mode).
• Knowledge of the cluster's Kubernetes version (kube-bench auto-detects, or specify with --version / --benchmark).
• Install kube-bench (Aqua Security official methods):

# Binary release (Linux)
KB_VERSION=0.10.7
curl -L -o kube-bench.tgz \
  "https://github.com/aquasecurity/kube-bench/releases/download/v${KB_VERSION}/kube-bench_${KB_VERSION}_linux_amd64.tar.gz"
tar -xzf kube-bench.tgz
sudo mv kube-bench /usr/local/bin/
sudo cp -R cfg /etc/kube-bench/cfg

# Via Go install
go install github.com/aquasecurity/kube-bench@latest

# Run as a one-off container directly on a node (mounts host config)
docker run --rm --pid=host \
  -v /etc:/etc:ro -v /var:/var:ro \
  -t docker.io/aquasec/kube-bench:latest run --targets node

# Verify
kube-bench version

Objectives

• Run kube-bench against the appropriate benchmark for the cluster's Kubernetes version.
• Scan control-plane (master), node, etcd, control-plane policies, and managed-service targets.
• Produce machine-readable JSON/JUnit output for pipelines and dashboards.
• Triage FAIL and WARN results and apply CIS remediation guidance.
• Re-run to validate that remediations now PASS.

MITRE ATT&CK Mapping

Workflow

1. Run the default scan (auto-detect)

Run all applicable targets, letting kube-bench detect the Kubernetes version and benchmark:

sudo kube-bench

2. Run as a Kubernetes Job (in-cluster)

Apply the provided Job manifest from the kube-bench repo and read the results from the pod logs:

# General-purpose job
kubectl apply -f https://raw.githubusercontent.com/aquasecurity/kube-bench/main/job.yaml

# Wait, then retrieve results
kubectl get pods -l app=kube-bench
kubectl logs -l app=kube-bench

# Platform-specific jobs are available, e.g. EKS:
kubectl apply -f https://raw.githubusercontent.com/aquasecurity/kube-bench/main/job-eks.yaml

3. Target specific components

Use run --targets to scope the scan to particular component groups:

# Control-plane (API server, scheduler, controller manager)

…