What it does. 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. Part of mukul975/Anthropic-Cybersecurity-Skills (817 security skills) (mukul975/Anthropic-Cybersecurity-Skills).
Install
npx skills add mukul975/Anthropic-Cybersecurity-Skills --skill securing-helm-chart-deployments, or copy the skill folder into ~/.claude/skills/securing-helm-chart-deployments/.- Raw file:
curl -sL https://raw.githubusercontent.com/mukul975/Anthropic-Cybersecurity-Skills/HEAD/skills/securing-helm-chart-deployments/SKILL.md
SKILL.md (verbatim)
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
Securing Helm Chart Deployments
Overview
Helm is the Kubernetes package manager. Securing Helm deployments requires validating chart provenance, scanning templates for security misconfigurations, enforcing pod security contexts, managing secrets securely, and controlling RBAC for Helm operations.
When to Use
- When deploying or configuring securing helm chart deployments capabilities in your environment
- When establishing security controls aligned to compliance requirements
- When building or improving security architecture for this domain
- When conducting security assessments that require this implementation
Prerequisites
- Helm 3.12+ installed
- kubectl with cluster access
- GnuPG for chart signing/verification
- kubesec or checkov for template scanning
Chart Provenance and Integrity
Sign a Helm Chart
# 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 Before Install
# 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
Template Security Scanning
Render and Scan Templates
# 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
Helm Lint for Misconfigurations
# Lint chart
helm lint ./mychart --values values-prod.yaml --strict
# Lint with debug output
helm lint ./mychart --debug
Security Context Enforcement in values.yaml
# 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..."
Template with Security Contexts
# 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 }}
Secrets Management
Use External Secrets (Not Helm Values)
# 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
helm-secrets Plugin
# 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
RBAC for Helm Operations
# 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
CI/CD Helm Security Pipeline
# .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
Best Practices
- Sign charts with GPG and verify before installation
- Render and scan templates before deploying to catch misconfigurations
- Enforce security contexts in values.yaml defaults
- Never store secrets in Helm values - use external secrets or helm-secrets plugin
- Use image digests instead of tags for immutable references
- Restrict Helm RBAC to least privilege per namespace
- Pin chart versions in requirements - never use
latest
- Lint strictly in CI with
--strict flag
- Review third-party charts before deploying to production
- Use Helm test hooks to validate deployments post-install
Other files in this skill
assets/template.md (verbatim)
Helm Chart Security Review Checklist
Security Context Defaults
Resource Management
Image Security
Secrets Handling
Network
RBAC
references/api-reference.md (verbatim)
API Reference: Securing Helm Chart Deployments
Helm Security Commands
| Command |
Description |
helm lint ./chart --strict |
Lint chart with strict mode |
helm template release ./chart |
Render templates locally |
helm verify chart.tgz |
Verify chart signature |
helm package ./chart --sign --key <key> |
Package and sign |
helm pull repo/chart --verify |
Pull with verification |
Security Context Fields
| Field |
Recommended |
Description |
runAsNonRoot |
true |
Prevent root execution |
readOnlyRootFilesystem |
true |
Immutable filesystem |
allowPrivilegeEscalation |
false |
Block privilege escalation |
capabilities.drop |
[ALL] |
Drop all Linux capabilities |
seccompProfile.type |
RuntimeDefault |
Syscall filtering |
Security Checks
| Check |
Severity |
Risk |
| Privileged container |
High |
Full host access |
| hostNetwork enabled |
High |
Network namespace escape |
| hostPID enabled |
High |
Process namespace escape |
| :latest image tag |
Medium |
Non-reproducible builds |
| Missing resource limits |
Medium |
Resource exhaustion DoS |
| Missing readOnlyRootFilesystem |
Medium |
Writable filesystem |
| Tool |
Command |
| kubesec |
kubesec scan rendered.yaml |
| checkov |
checkov -f rendered.yaml --framework kubernetes |
| trivy |
trivy config rendered.yaml |
| kube-linter |
kube-linter lint rendered.yaml |
Python Libraries
| Library |
Version |
Purpose |
subprocess |
stdlib |
Execute helm/kubesec CLI |
re |
stdlib |
Pattern matching in rendered YAML |
yaml |
PyYAML >=6.0 |
Parse YAML content |
json |
stdlib |
Report generation |
References
references/standards.md (verbatim)
Standards and References - Securing Helm Chart Deployments
NIST SP 800-190
- Section 4.1: Image vulnerabilities and configuration defects
- Section 5.2: Registry security and chart provenance
- Section 5.4: Secure deployment configuration
CIS Kubernetes Benchmark v1.8
- 5.2.1-5.2.9: Pod Security Standards enforced via chart defaults
- 5.7.3: Apply security context to pods and containers
SLSA (Supply chain Levels for Software Artifacts)
- Level 1: Documented build process (Helm chart CI)
- Level 2: Source version controlled, signed provenance
- Level 3: Hardened build platform, signed artifacts
- Level 4: Two-party review, hermetic builds
Helm Security Resources
Compliance Mappings
PCI DSS v4.0
- Req 6.3.1: Security vulnerabilities identified and managed
- Req 6.5.1: Changes controlled by change control processes
SOC 2
- CC8.1: Change management - Controlled deployment processes
references/workflows.md (verbatim)
Workflow - Securing Helm Chart Deployments
Phase 1: Chart Development Security
- Set secure defaults in values.yaml (non-root, read-only fs, resource limits)
- Add network policy templates
- Use external secrets references
- Lint with
helm lint --strict
Phase 2: CI Pipeline
- Render templates:
helm template test ./chart -f values.yaml > rendered.yaml
- Lint:
helm lint ./chart --strict
- Scan:
kube-linter lint rendered.yaml
- Scan:
checkov -f rendered.yaml --framework kubernetes
- Sign chart:
helm package ./chart --sign
Phase 3: Deployment
- Verify chart signature:
helm verify chart.tgz
- Deploy with production values:
helm install release ./chart -f values-prod.yaml
- Verify deployment:
helm test release
Phase 4: Post-Deployment
- Validate security contexts:
kubectl get pods -o jsonpath='{.items[*].spec.securityContext}'
- Check network policies applied
- Verify secrets sourced from external store
Phase 5: Maintenance
- Update chart versions in lockfile
- Rescan after dependency updates
- Rotate signing keys annually
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