scanning-kubernetes-manifests-with-kubesec

Perform security risk analysis on Kubernetes resource manifests using Kubesec to identify misconfigurations, privilege escalation risks, and deviations from security best practices. Use when performing security risk analysis on kubernetes resource manifests using kubesec.

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Repository: oyi77/1ai-skills
Last source activity: July 31, 2026 at 15:22
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name	scanning-kubernetes-manifests-with-kubesec
description	Perform security risk analysis on Kubernetes resource manifests using Kubesec to identify misconfigurations, privilege escalation risks, and deviations from security best practices. Use when performing security risk analysis on kubernetes resource manifests using kubesec.
domain	cybersecurity
subdomain	container-security
tags	["kubesec","kubernetes","manifest-scanning","security-scanning","devsecops","misconfiguration","static-analysis","ci-cd"]
version	1.0
author	oyi77
license	Apache-2.0
nist_csf	["PR.PS-01","PR.IR-01","ID.AM-08","DE.CM-01"]

Scanning Kubernetes Manifests with Kubesec

Overview

Kubesec is an open-source security risk analysis tool developed by ControlPlane that inspects Kubernetes resource manifests for common exploitable risks such as privilege escalation, writable host mounts, and excessive capabilities. It assigns a numerical security score to each resource and provides actionable recommendations for hardening. Kubesec can be used as a CLI binary, Docker container, kubectl plugin, admission webhook, or REST API endpoint.

When to Use

Trigger phrases:

"scanning kubernetes manifests with kubesec"
"Perform security risk analysis on Kubernetes resource manifests using Kubesec to"
When conducting security assessments that involve scanning kubernetes manifests with kubesec
When following incident response procedures for related security events
When performing scheduled security testing or auditing activities
When validating security controls through hands-on testing

Prerequisites

Kubernetes manifest files (YAML/JSON) for Deployments, Pods, DaemonSets, StatefulSets
Docker or Go runtime for local installation
kubectl access for scanning live cluster resources
CI/CD pipeline access for automated scanning integration

Core Concepts

This section covers core concepts for scanning kubernetes manifests with kubesec.

Ensure all prerequisites are met before proceeding
Follow the documented workflow steps in sequence
Record results and any anomalies encountered during this phase

Security Scoring System

Kubesec assigns a score to each Kubernetes resource based on security checks:

Positive scores: Awarded for security-enhancing configurations (readOnlyRootFilesystem, runAsNonRoot)
Zero or negative scores: Indicate missing security controls or dangerous configurations
Critical advisories: Flagged configurations that represent immediate security risks

Check Categories

Privilege Controls: Checks for privileged containers, host PID/network access, root execution
Capabilities: Identifies excessive Linux capabilities (SYS_ADMIN, NET_RAW)
Volume Mounts: Detects dangerous host path mounts and writable sensitive paths
Resource Limits: Validates presence of CPU/memory resource constraints

# Install required dependencies
sudo apt-get update && sudo apt-get install -y <tool-name>

# Linux/macOS
curl -sSL https://github.com/controlplaneio/kubesec/releases/latest/download/kubesec_linux_amd64.tar.gz | \
  tar xz -C /usr/local/bin/ kubesec

# Verify installation
kubesec version

docker pull kubesec/kubesec:v2

# Scan a manifest file
docker run -i kubesec/kubesec:v2 scan /dev/stdin < deployment.yaml

kubectl krew install kubesec-scan
kubectl kubesec-scan pod mypod -n default

# Scan a deployment manifest
kubesec scan deployment.yaml

# Scan with JSON output
kubesec scan -o json deployment.yaml

# Scan from stdin
cat pod.yaml | kubesec scan -

[
  {
    "object": "Pod/web-app.default",
    "valid": true,
    "fileName": "pod.yaml",
    "message": "Passed with a score of 3 points",
    "score": 3,
    "scoring": {
      "passed": [
        {
          "id": "ReadOnlyRootFilesystem",
          "selector": "containers[] .securityContext .readOnlyRootFilesystem == true",
          "reason": "An immutable root filesystem prevents applications from writing to their local disk",
          "points": 1
        },
        {
          "id": "RunAsNonRoot",
          "selector": "containers[] .securityContext .runAsNonRoot == true",
          "reason": "Force the running image to run as a non-root user",
          "points": 1
        },
        {
          "id": "LimitsCPU",
          "selector": "containers[] .resources .limits .cpu",
          "reason": "Enforcing CPU limits prevents DOS via resource exhaustion",
          "points": 1
        }
      ],
      "advise": [
        {
          "id": "ApparmorAny",
          "selector": "metadata .annotations .\"container.apparmor.security.beta.kubernetes.io/nginx\"",
          "reason": "Well defined AppArmor policies reduce the attack surface of the container",
          "points": 3
        },
        {
          "id": "ServiceAccountName",
          "selector": ".spec .serviceAccountName",
          "reason": "Service accounts restrict Kubernetes API access and should be configured",
          "points": 3
        }
      ]
    }
  }
]

# Scan all YAML files in a directory
for file in manifests/*.yaml; do
  echo "=== Scanning $file ==="
  kubesec scan "$file"
done

# Scan multi-document YAML
kubesec scan multi-resource.yaml

# Scan via the public API
curl -sSX POST --data-binary @deployment.yaml \
  https://v2.kubesec.io/scan

# Run a local API server
kubesec http --port 8080 &

# Scan against local server
curl -sSX POST --data-binary @deployment.yaml \
  http://localhost:8080/scan

name: Kubesec Scan
on: [pull_request]
jobs:
  kubesec:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install Kubesec
        run: |
          curl -sSL https://github.com/controlplaneio/kubesec/releases/latest/download/kubesec_linux_amd64.tar.gz | \
            tar xz -C /usr/local/bin/ kubesec
      - name: Scan Manifests
        run: |
          FAIL=0
          for file in k8s/*.yaml; do
            SCORE=$(kubesec scan "$file" | jq '.[0].score')
            echo "$file: score=$SCORE"
            if [ "$SCORE" -lt 0 ]; then
              echo "FAIL: $file has critical issues (score: $SCORE)"
              FAIL=1
            fi
          done
          exit $FAIL

kubesec-scan:
  stage: security
  image: kubesec/kubesec:v2
  script:
    - |
      for file in k8s/*.yaml; do
        kubesec scan "$file" > /tmp/result.json
        SCORE=$(cat /tmp/result.json | jq '.[0].score')
        if [ "$SCORE" -lt 0 ]; then
          echo "CRITICAL: $file scored $SCORE"
          cat /tmp/result.json | jq '.[0].scoring.critical'
          exit 1
        fi
      done
  artifacts:
    paths:
      - kubesec-results/

apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingWebhookConfiguration
metadata:
  name: kubesec-webhook
webhooks:
  - name: kubesec.controlplane.io
    rules:
      - apiGroups: [""]
        apiVersions: ["v1"]
        operations: ["CREATE", "UPDATE"]
        resources: ["pods"]
      - apiGroups: ["apps"]
        apiVersions: ["v1"]
        operations: ["CREATE", "UPDATE"]
        resources: ["deployments", "daemonsets", "statefulsets"]
    clientConfig:
      service:
        name: kubesec-webhook
        namespace: kube-system
        path: /scan
    failurePolicy: Fail
    sideEffects: None
    admissionReviewVersions: ["v1"]

Reference	Description
NIST SP 800-86	Guide to Integrating Forensic Techniques into Incident Response
MITRE ATT&CK	Knowledge base of adversary tactics and techniques
OWASP Testing Guide	Web application security testing methodology

Check	Selector	Risk
Privileged	`securityContext.privileged == true`	Full host access
HostPID	`spec.hostPID == true`	Process namespace escape
HostNetwork	`spec.hostNetwork == true`	Network namespace escape
SYS_ADMIN	`capabilities.add contains SYS_ADMIN`	Near-root capability

Check	Points	Description
ReadOnlyRootFilesystem	+1	Prevents filesystem writes
RunAsNonRoot	+1	Non-root process execution
RunAsUser > 10000	+1	High UID reduces collision risk
LimitsCPU	+1	Prevents CPU resource exhaustion
LimitsMemory	+1	Prevents memory resource exhaustion
RequestsCPU	+1	Ensures scheduler resource awareness
ServiceAccountName	+3	Explicit service account
AppArmor annotation	+3	Kernel-level MAC enforcement
Seccomp profile	+4	Syscall filtering

Rationalization	Reality
"We are too small to be targeted"	Automated attacks target everyone. Size does not matter.
"Security slows us down"	A breach slows you down 100x more. Build security in from the start.
"We will fix it after launch"	Vulnerabilities in production are exploited within hours. Fix before deploy.