Securing Helm Chart Deployments

What it does

When your agent uses it

• Deploying charts to Kubernetes
• Reviewing chart provenance
• Scanning the rendered manifests themselves - use scanning-kubernetes-manifests-with-kubesec

Example prompts

• “Use the securing-helm-chart-deployments skill to secure Helm chart deployments by verifying chart signatures and provenance, rendering and linting…”
• “/securing-helm-chart-deployments”

Requirements

• Python 3

Workflow steps

10 steps, taken from the first numbered list in SKILL.md.

1. 1Sign charts with GPG and verify before installation
2. 2Render and scan templates before deploying to catch misconfigurations
3. 3Enforce security contexts in values.yaml defaults
4. 4Never store secrets in Helm values - use external secrets or helm-secrets plugin
5. 5Use image digests instead of tags for immutable references
6. 6Restrict Helm RBAC to least privilege per namespace
7. 7Pin chart versions in requirements - never use latest
8. 8Lint strictly in CI with --strict flag
9. 9Review third-party charts before deploying to production
10. 10Use Helm test hooks to validate deployments post-install

What it can do on your machine

Read from SKILL.md and the folder at commit 54a7988. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 2 files in scripts/ (Python), which the agent can run.

  Shell commands in SKILL.md call:

  • helm
  • trivy

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • github.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Securing Helm Chart Deployments loads about 1.9k tokens when it runs, and up to ~3k if it reads all its reference files. Until then it costs about 162 tokens; SKILL.md has 238 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~162

When it runs · the whole SKILL.md, loaded when a task matches

~1.9k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• WarningMentions a credentials file (SSH keys, cloud or package-manager tokens)SKILL.md:66

  "helm-signing@example.com" --keyring ~/.gnupg/pubring.gpg

• WarningMentions a credentials file (SSH keys, cloud or package-manager tokens)SKILL.md:69

  lm verify mychart-0.1.0.tgz --keyring ~/.gnupg/pubring.gpg

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from mukul975/Anthropic-Cybersecurity-Skills at commit 54a7988, republished under its Apache-2.0 licence (© mukul975). 238 words, ~1,868 tokens.

name

securing-helm-chart-deployments

description

Secures Helm chart deployments by verifying chart signatures and provenance, rendering and linting templates for misconfiguration, enforcing pod security contexts through values.yaml, moving secrets into an external store instead of Helm values, and scoping RBAC for Helm operations in CI/CD. Use when deploying charts to Kubernetes or reviewing chart provenance, templates, or release RBAC. Keywords: Helm, provenance file, helm verify, helm lint, values.yaml, Tiller-less, release RBAC, external secrets. Do not use for scanning the rendered manifests themselves - use scanning-kubernetes-manifests-with-kubesec.

domain

cybersecurity

subdomain

container-security

tags

helm, kubernetes, chart-security, supply-chain, configuration-security, deployment

version

1.0

author

mahipal

license

Apache-2.0

nist_csf

PR.PS-01, PR.IR-01, ID.AM-08, DE.CM-01

mitre_attack

T1610, T1611, T1609, T1525, T1195

# Generate GPG key for signing
gpg --full-generate-key

# Package and sign chart
helm package ./mychart --sign --key "helm-signing@example.com" --keyring ~/.gnupg/pubring.gpg

# Verify chart signature
helm verify mychart-0.1.0.tgz --keyring ~/.gnupg/pubring.gpg

# Verify chart from repository
helm pull myrepo/mychart --verify --keyring /path/to/keyring.gpg

# Check chart provenance file
cat mychart-0.1.0.tgz.prov

# Render templates without deploying
helm template myrelease ./mychart --values values-prod.yaml > rendered.yaml

# Scan with kubesec
kubesec scan rendered.yaml

# Scan with checkov
checkov -f rendered.yaml --framework kubernetes

# Scan with trivy
trivy config rendered.yaml

# Scan with kube-linter
kube-linter lint rendered.yaml

# Lint chart
helm lint ./mychart --values values-prod.yaml --strict

# Lint with debug output
helm lint ./mychart --debug

# values.yaml - Security hardened defaults
securityContext:
  runAsNonRoot: true
  runAsUser: 1000
  runAsGroup: 3000
  fsGroup: 2000
  readOnlyRootFilesystem: true
  allowPrivilegeEscalation: false
  capabilities:
    drop:
      - ALL

podSecurityContext:
  seccompProfile:
    type: RuntimeDefault

resources:
  limits:
    cpu: 500m
    memory: 512Mi
  requests:
    cpu: 100m
    memory: 128Mi

networkPolicy:
  enabled: true

serviceAccount:
  create: true
  automountServiceAccountToken: false

image:
  pullPolicy: Always
  # Use digest instead of tag for immutability
  # tag: "1.0.0"
  # digest: "sha256:abc123..."

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "mychart.fullname" . }}
spec:
  template:
    spec:
      automountServiceAccountToken: {{ .Values.serviceAccount.automountServiceAccountToken }}
      securityContext:
        {{- toYaml .Values.podSecurityContext | nindent 8 }}
      containers:
        - name: {{ .Chart.Name }}
          securityContext:
            {{- toYaml .Values.securityContext | nindent 12 }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          resources:
            {{- toYaml .Values.resources | nindent 12 }}

# templates/external-secret.yaml
apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
  name: {{ include "mychart.fullname" . }}-secrets
spec:
  refreshInterval: 1h
  secretStoreRef:
    name: aws-secretsmanager
    kind: ClusterSecretStore
  target:
    name: {{ include "mychart.fullname" . }}-secrets
  data:
    - secretKey: db-password
      remoteRef:
        key: production/database
        property: password

# Install helm-secrets plugin
helm plugin install https://github.com/jkroepke/helm-secrets

# Encrypt values file
helm secrets encrypt values-secrets.yaml

# Deploy with encrypted secrets
helm secrets install myrelease ./mychart -f values.yaml -f values-secrets.yaml

# Decrypt for editing
helm secrets edit values-secrets.yaml

# helm-deployer-role.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: helm-deployer
  namespace: production
rules:
  - apiGroups: ["", "apps", "batch", "networking.k8s.io"]
    resources: ["deployments", "services", "configmaps", "secrets", "ingresses", "jobs"]
    verbs: ["get", "list", "create", "update", "patch", "delete"]
  - apiGroups: [""]
    resources: ["pods", "pods/log"]
    verbs: ["get", "list"]

---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: helm-deployer-binding
  namespace: production
subjects:
  - kind: ServiceAccount
    name: helm-deployer
    namespace: production
roleRef:
  kind: Role
  name: helm-deployer
  apiGroup: rbac.authorization.k8s.io

# .github/workflows/helm-security.yaml
name: Helm Chart Security
on:
  pull_request:
    paths: ['charts/**']

jobs:
  lint-and-scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Helm lint
        run: helm lint ./charts/mychart --strict

      - name: Render templates
        run: helm template test ./charts/mychart -f charts/mychart/values.yaml > rendered.yaml

      - name: Scan with kube-linter
        uses: stackrox/kube-linter-action@v1
        with:
          directory: rendered.yaml

      - name: Scan with trivy
        uses: aquasecurity/trivy-action@master
        with:
          scan-type: config
          scan-ref: rendered.yaml

      - name: Scan with checkov
        uses: bridgecrewio/checkov-action@master
        with:
          file: rendered.yaml
          framework: kubernetes

© mukul975, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 7 other files (scripts, references, assets) in skills/securing-helm-chart-deployments of mukul975/Anthropic-Cybersecurity-Skills.

• SKILL.md
• LICENSE
• assets/template.md
• references/api-reference.md
• references/standards.md
• references/workflows.md
• scripts/agent.py
• scripts/process.py

Open the folder on GitHubat commit 54a7988