Securing Container Registry with Harbor

Overview

Harbor is an open-source container registry that provides security features including vulnerability scanning (integrated Trivy), image signing (Notary/Cosign), RBAC, content trust policies, replication, and audit logging. Securing Harbor involves configuring these features to enforce image provenance, prevent vulnerable image deployment, and maintain registry access control.

When to Use

When deploying or configuring securing container registry with harbor 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

Harbor 2.10+ installed (Helm or Docker Compose)
TLS certificates for HTTPS
Trivy scanner integration
OIDC/LDAP for authentication
Kubernetes cluster (for deployment target)

Workflow

Step 1: Install Harbor with Security Configuration

# harbor-values.yaml for Helm deployment
expose:
  type: ingress
  tls:
    enabled: true
    certSource: secret
    secret:
      secretName: harbor-tls
      notarySecretName: harbor-tls
  ingress:
    hosts:
      core: harbor.example.com
      notary: notary.example.com

externalURL: https://harbor.example.com

persistence:
  enabled: true
  resourcePolicy: "keep"

harborAdminPassword: "<strong-password>"

trivy:
  enabled: true
  gitHubToken: "<github-token>"
  severity: "CRITICAL,HIGH,MEDIUM"
  autoScan: true

notary:
  enabled: true

core:
  secretKey: "<32-char-secret>"

database:
  type: external
  external:
    host: postgres.example.com
    port: "5432"
    username: harbor
    password: "<db-password>"
    sslmode: require

helm repo add harbor https://helm.getharbor.io
helm install harbor harbor/harbor -f harbor-values.yaml -n harbor --create-namespace

Step 2: Configure Vulnerability Scanning Policies

# Enable auto-scan on push (via Harbor API)
curl -k -X PUT "https://harbor.example.com/api/v2.0/projects/myproject" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "metadata": {
      "auto_scan": "true",
      "severity": "critical",
      "prevent_vul": "true",
      "reuse_sys_cve_allowlist": "true"
    }
  }'

Step 3: Configure Content Trust

# Enable content trust at project level
curl -k -X PUT "https://harbor.example.com/api/v2.0/projects/myproject" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "metadata": {
      "enable_content_trust": "true",
      "enable_content_trust_cosign": "true"
    }
  }'

# Sign image with Cosign
cosign sign --key cosign.key harbor.example.com/myproject/myapp:v1.0.0

# Verify signature
cosign verify --key cosign.pub harbor.example.com/myproject/myapp:v1.0.0

Step 4: Configure RBAC and Project Isolation

# Create project with private visibility
curl -k -X POST "https://harbor.example.com/api/v2.0/projects" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "project_name": "production",
    "metadata": {
      "public": "false",
      "auto_scan": "true",
      "prevent_vul": "true",
      "severity": "high"
    }
  }'

# Harbor roles: ProjectAdmin, Maintainer, Developer, Guest, LimitedGuest
# Add member with specific role
curl -k -X POST "https://harbor.example.com/api/v2.0/projects/production/members" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "role_id": 3,
    "member_user": {"username": "developer1"}
  }'

Step 5: Configure Immutable Tags and Retention

# Create tag immutability rule (prevent overwriting release tags)
curl -k -X POST "https://harbor.example.com/api/v2.0/projects/production/immutabletagrules" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "tag_filter": "v*",
    "scope_selectors": {
      "repository": [{"kind": "doublestar", "decoration": "repoMatches", "pattern": "**"}]
    }
  }'

# Configure retention policy (keep last 10 tags, delete untagged after 7 days)
curl -k -X POST "https://harbor.example.com/api/v2.0/retentions" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)" \
  -H "Content-Type: application/json" \
  -d '{
    "algorithm": "or",
    "rules": [
      {
        "action": "retain",
        "template": "latestPushedK",
        "params": {"latestPushedK": 10},
        "tag_selectors": [{"kind": "doublestar", "decoration": "matches", "pattern": "**"}],
        "scope_selectors": {"repository": [{"kind": "doublestar", "decoration": "repoMatches", "pattern": "**"}]}
      }
    ],
    "trigger": {"kind": "Schedule", "settings": {"cron": "0 0 * * *"}}
  }'

Step 6: OIDC Authentication Integration

# Harbor configuration for OIDC
auth_mode: oidc_auth
oidc_name: "Okta"
oidc_endpoint: "https://company.okta.com/oauth2/default"
oidc_client_id: "harbor-client-id"
oidc_client_secret: "harbor-client-secret"
oidc_groups_claim: "groups"
oidc_admin_group: "harbor-admins"
oidc_scope: "openid,profile,email,groups"
oidc_verify_cert: true
oidc_auto_onboard: true

Validation Commands

# Test vulnerability prevention (should block pull of vulnerable image)
docker pull harbor.example.com/production/vulnerable-app:latest
# Expected: Error - image blocked due to vulnerabilities

# Verify content trust enforcement
DOCKER_CONTENT_TRUST=0 docker push harbor.example.com/production/unsigned:latest
# Expected: Push rejected due to content trust policy

# Check scan results via API
curl -k "https://harbor.example.com/api/v2.0/projects/production/repositories/myapp/artifacts/v1.0.0/additions/vulnerabilities" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)"

# Audit log check
curl -k "https://harbor.example.com/api/v2.0/audit-logs?page=1&page_size=10" \
  -H "Authorization: Basic $(echo -n admin:Harbor12345 | base64)"

Harbor