Binary Authorization

Overview

Binary Authorization is a deploy-time security control that ensures only trusted container images run on GKE. Images must be cryptographically signed and verified before deployment, preventing supply chain attacks and unauthorized images.

Image Signing

CI/CD signs images with KMS keys

Policy Enforcement

GKE blocks unsigned images

Attestations

Proof of CI/CD approval

Audit Trail

All denials logged to Cloud Logging

Why Binary Authorization?

Prevent Unauthorized Images

Threat: Attacker pushes malicious image to registryProtection: Only images signed by your CI/CD can deployExample blocked scenarios:

Directly pushed images (bypassing CI/CD)
Images from unknown registries
Tampered images (signature verification fails)

Supply Chain Security

Compliance: SLSA Level 3, SOC 2, HIPAARequirement: Prove images were built by authorized systemsBinary Auth provides:

Cryptographic proof of build provenance
Attestations from CI/CD pipeline
Immutable audit trail

Multi-Environment Control

Problem: Dev images shouldn’t reach productionSolution: Different attestors per environmentImplementation:

Dev: Allow all (no signing)
Staging: Require staging attestor (audit mode)
Prod: Require prod attestor (enforcing mode)

Incident Response

Scenario: Compromised CI/CD pipelineResponse: Revoke KMS key, all signed images instantly blockedRecovery: Create new KMS key, re-sign trusted images

Architecture

Flow:

CI/CD builds and tests image
Push image to Artifact Registry
Sign image digest with KMS key
Create attestation (proof of signature)
On deployment, GKE checks attestation
If valid → Deploy; If invalid → Block

Quick Setup (20 minutes)

Enable APIs

gcloud services enable \
  binaryauthorization.googleapis.com \
  containeranalysis.googleapis.com \
  containerscanning.googleapis.com \
  --project=PROJECT_ID

Run Setup Script

./deployments/security/binary-authorization/setup-binary-auth.sh \
  PROJECT_ID production

What it creates:

KMS key ring and signing key
Container Analysis note
Attestor resource
Binary Authorization policy

Enable on GKE Cluster

Terraform
gcloud CLI

terraform/environments/gcp-prod/terraform.tfvars

enable_binary_authorization    = true
binary_authorization_mode      = "ENFORCING"

terraform apply

Sign First Image

./deployments/security/binary-authorization/sign-image.sh \
  PROJECT_ID production \
  us-central1-docker.pkg.dev/PROJECT_ID/mcp-production/mcp-server-langgraph:v1.0.0

Creates attestation for the image.

Verify Policy

# Try deploying unsigned image (should fail)
kubectl run test --image=nginx:latest

# Should see error:
# Error: admission webhook denied the request

# Deploy signed image (should succeed)
kubectl apply -k deployments/overlays/production-gke

Policy Configuration

Policy Modes

Enforcing (Production)
Audit (Staging)
Disabled (Development)

evaluationMode: REQUIRE_ATTESTATION
enforcementMode: ENFORCING_MODE

Behavior: Blocks unsigned imagesUse case: Production environmentsRisk: Zero tolerance for unsigned images

Environment-Specific Policies

apiVersion: binaryauthorization.googleapis.com/v1
kind: Policy
metadata:
  name: production-policy
spec:
  globalPolicyEvaluationMode: ENABLE
  defaultAdmissionRule:
    evaluationMode: REQUIRE_ATTESTATION
    enforcementMode: ENFORCING_MODE
    requireAttestationsBy:
      - projects/PROJECT_ID/attestors/production-attestor

  # Exception for system images
  clusterAdmissionRules:
    us-central1.production-mcp-server-langgraph-gke:
      evaluationMode: REQUIRE_ATTESTATION
      enforcementMode: ENFORCING_MODE
      requireAttestationsBy:
        - projects/PROJECT_ID/attestors/production-attestor

  # Allow GKE system images
  admissionWhitelistPatterns:
    - namePattern: gcr.io/gke-release/*
    - namePattern: gke.gcr.io/*
    - namePattern: k8s.gcr.io/*

Image Signing in CI/CD

GitHub Actions Integration

name: Deploy to Production GKE
on:
  push:
    tags:
      - 'v*'

jobs:
  build-sign-deploy:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      id-token: write  # For Workload Identity Federation

    steps:
      - uses: actions/checkout@v4

      - name: Authenticate to GCP
        uses: google-github-actions/auth@v2
        with:
          workload_identity_provider: 'projects/PROJECT_NUMBER/locations/global/workloadIdentityPools/github/providers/github'
          service_account: 'github-actions@PROJECT_ID.iam.gserviceaccount.com'

      - name: Configure Docker for Artifact Registry
        run: gcloud auth configure-docker us-central1-docker.pkg.dev

      - name: Build Image
        run: |
          docker build -t us-central1-docker.pkg.dev/PROJECT_ID/mcp-production/mcp-server-langgraph:${{ github.ref_name }} .

      - name: Push Image
        run: |
          docker push us-central1-docker.pkg.dev/PROJECT_ID/mcp-production/mcp-server-langgraph:${{ github.ref_name }}

      - name: Sign Image
        run: |
          IMAGE_URL="us-central1-docker.pkg.dev/PROJECT_ID/mcp-production/mcp-server-langgraph:${{ github.ref_name }}"
          IMAGE_DIGEST=$(gcloud artifacts docker images describe $IMAGE_URL --format='get(image_summary.digest)')

          # Create attestation
          gcloud beta container binauthz attestations sign-and-create \
            --artifact-url="us-central1-docker.pkg.dev/PROJECT_ID/mcp-production/mcp-server-langgraph@${IMAGE_DIGEST}" \
            --attestor=production-attestor \
            --attestor-project=PROJECT_ID \
            --keyversion-project=PROJECT_ID \
            --keyversion-location=us-central1 \
            --keyversion-keyring=production-binauthz \
            --keyversion-key=attestor-key \
            --keyversion=1

      - name: Deploy to GKE
        run: |
          kubectl apply -k deployments/overlays/production-gke
```bash
```bash Manual Signing Script
#!/bin/bash
# deployments/security/binary-authorization/sign-image.sh

PROJECT_ID="$1"
ENVIRONMENT="$2"
IMAGE_URL="$3"

# Get image digest
IMAGE_DIGEST=$(gcloud artifacts docker images describe "$IMAGE_URL" \
  --format='get(image_summary.digest)')

# Extract registry and image name
REGISTRY=$(echo "$IMAGE_URL" | cut -d'/' -f1)
REPO_PATH=$(echo "$IMAGE_URL" | cut -d':' -f1 | cut -d'/' -f2-)

ARTIFACT_URL="${REGISTRY}/${REPO_PATH}@${IMAGE_DIGEST}"

echo "Signing image: $ARTIFACT_URL"

# Create attestation
gcloud beta container binauthz attestations sign-and-create \
  --artifact-url="$ARTIFACT_URL" \
  --attestor="${ENVIRONMENT}-attestor" \
  --attestor-project="$PROJECT_ID" \
  --keyversion-project="$PROJECT_ID" \
  --keyversion-location=us-central1 \
  --keyversion-keyring="${ENVIRONMENT}-binauthz" \
  --keyversion-key=attestor-key \
  --keyversion=1

echo "✅ Image signed successfully"

Verification & Troubleshooting

Check Policy Status

# View current policy
gcloud container binauthz policy export

# Check attestor
gcloud container binauthz attestors describe production-attestor \
  --project=PROJECT_ID

# List attestations for image
gcloud container binauthz attestations list \
  --artifact-url="us-central1-docker.pkg.dev/PROJECT_ID/mcp-production/mcp-server-langgraph@sha256:ABC123" \
  --attestor=production-attestor \
  --attestor-project=PROJECT_ID

View Denials in Logs

# Check Binary Auth denials
gcloud logging read \
  'protoPayload.serviceName="binaryauthorization.googleapis.com" AND protoPayload.response.allow=false' \
  --limit=50 \
  --format=json

# Denied image details
gcloud logging read \
  'resource.type="k8s_cluster" AND protoPayload.request.spec.containers[].image=~"mcp-server"' \
  --limit=10

Common Issues

Error: Image not attested

Symptom: Deployment blocked with “image not attested by projects/PROJECT/attestors/production-attestor”Cause: Image hasn’t been signed by CI/CDSolution:

# Verify attestation exists
gcloud container binauthz attestations list \
  --artifact-url=IMAGE_URL@DIGEST \
  --attestor=production-attestor

# If missing, sign manually
./deployments/security/binary-authorization/sign-image.sh \
  PROJECT_ID production IMAGE_URL

Error: Attestor not found

Symptom: “attestor not found: projects/PROJECT/attestors/production-attestor”Cause: Attestor resource not createdSolution:

# Re-run setup
./deployments/security/binary-authorization/setup-binary-auth.sh \
  PROJECT_ID production

GKE system images blocked

Symptom: System pods (kube-proxy, node-exporter) failing to startCause: Missing admission whitelist patternsSolution: Add to policy:

admissionWhitelistPatterns:
  - namePattern: gcr.io/gke-release/*
  - namePattern: gke.gcr.io/*
  - namePattern: k8s.gcr.io/*

KMS permission denied

Symptom: CI/CD can’t sign images - “Permission denied on KMS key”Solution:

# Grant CI/CD service account KMS permissions
gcloud kms keys add-iam-policy-binding attestor-key \
  --location=us-central1 \
  --keyring=production-binauthz \
  --member="serviceAccount:github-actions@PROJECT_ID.iam.gserviceaccount.com" \
  --role="roles/cloudkms.signerVerifier" \
  --project=PROJECT_ID

Security Best Practices

Separate keys per environment

# Production key
production-binauthz/attestor-key

# Staging key (different key ring)
staging-binauthz/attestor-key

# Development (no signing required)

Benefit: Key compromise doesn’t affect all environments

Rotate KMS keys regularly

# Create new key version (automatic rotation)
gcloud kms keys versions create \
  --location=us-central1 \
  --keyring=production-binauthz \
  --key=attestor-key

Enable KMS key rotation policy

gcloud kms keys update attestor-key \
  --location=us-central1 \
  --keyring=production-binauthz \
  --rotation-period=90d \
  --next-rotation-time=2025-04-01T00:00:00Z

Audit attestations regularly

# List all attestations in last 7 days
gcloud logging read \
  'protoPayload.serviceName="binaryauthorization.googleapis.com" AND protoPayload.methodName="google.cloud.binaryauthorization.v1.BinauthzManagementService.CreateAttestor"' \
  --freshness=7d

Principle of least privilege

# CI/CD SA: Only signer role (can create attestations)
gcloud kms keys add-iam-policy-binding attestor-key \
  --role=roles/cloudkms.signerVerifier \
  --member="serviceAccount:ci-cd@PROJECT.iam.gserviceaccount.com"

# GKE SA: Only verifier role (can check attestations)
# Automatic via Workload Identity

Compliance & Auditing

SOC 2 / HIPAA Requirements

Control Objectives Met
Audit Evidence

✅ CC6.1: Logical access controls
- Only signed images can deploy
- Attestations prove CI/CD approval
✅ CC6.6: Logical access segregation
- Production attestor separate from dev/staging
- KMS keys isolated per environment
✅ CC7.2: System monitoring
- All denials logged to Cloud Logging
- Attestation creation audited
✅ CC8.1: Change management
- All deployments require signed images
- Git commit → CI/CD → Attestation chain

SLSA Level 3 Compliance

Binary Authorization helps achieve SLSA Level 3 (Supply Chain Levels for Software Artifacts):

Requirement	Implementation
Provenance	Attestations prove build provenance
Non-falsifiable	KMS signatures can’t be forged
Auditable	All attestations logged
Hermetic	Only CI/CD can create attestations

Migration Path

1. Enable in Audit Mode (Dev)

# Development cluster - audit only
gcloud container clusters update mcp-dev-gke \
  --binauthz-evaluation-mode=POLICY_BINDINGS \
  --region=us-central1

No enforcement, just logging.

2. Test Signing in CI/CD

Add signing step to CI/CD, verify attestations created.Monitor for 1 week, ensure no failures.

3. Enable Audit Mode (Staging)

# Staging cluster - audit mode
# Terraform: binary_authorization_mode = "DRYRUN_AUDIT_LOG_ONLY"
terraform apply

Monitor denials, fix any unsigned images.

4. Enable Enforcing (Production)

# Production cluster - enforcing
# Terraform: binary_authorization_mode = "ENFORCING"
terraform apply

Only after:

All images signed
No denials in staging for 2 weeks
Rollback plan tested

GKE Production

Production deployment with Binary Auth enabled

Security Hardening

Complete 67-control security framework

GitOps (ArgoCD)

Automated deployments with image signing

CI/CD Pipeline

GitHub Actions with Binary Auth integration

Next Steps

Set Up Binary Authorization

./deployments/security/binary-authorization/setup-binary-auth.sh PROJECT_ID production

Integrate with CI/CD

Add image signing step to GitHub Actions workflow

Enable on Cluster

enable_binary_authorization = true
binary_authorization_mode = "ENFORCING"

Monitor Denials

gcloud logging read 'protoPayload.response.allow=false' --limit=10

Getting Started

Deployment Options

LangGraph Platform

Kubernetes - GKE

Kubernetes - EKS & AKS

Kubernetes - Best Practices

Infrastructure as Code

Monitoring & Observability

Advanced Deployment

Configuration

Operations

Overview

Image Signing

Policy Enforcement

Attestations

Audit Trail

Why Binary Authorization?

Architecture

Quick Setup (20 minutes)

Policy Configuration

Policy Modes

Environment-Specific Policies

Image Signing in CI/CD

GitHub Actions Integration

Verification & Troubleshooting

Check Policy Status

View Denials in Logs

Common Issues

Security Best Practices

Compliance & Auditing

SOC 2 / HIPAA Requirements

SLSA Level 3 Compliance

Migration Path

GKE Production

Security Hardening

GitOps (ArgoCD)

CI/CD Pipeline

Next Steps

Getting Started

Deployment Options

LangGraph Platform

Kubernetes - GKE

Kubernetes - EKS & AKS

Kubernetes - Best Practices

Infrastructure as Code

Monitoring & Observability

Advanced Deployment

Configuration

Operations

​Overview

Image Signing

Policy Enforcement

Attestations

Audit Trail

​Why Binary Authorization?

​Architecture

​Quick Setup (20 minutes)

​Policy Configuration

​Policy Modes

​Environment-Specific Policies

​Image Signing in CI/CD

​GitHub Actions Integration

​Verification & Troubleshooting

​Check Policy Status

​View Denials in Logs

​Common Issues

​Security Best Practices

​Compliance & Auditing

​SOC 2 / HIPAA Requirements

​SLSA Level 3 Compliance

​Migration Path

​Related Documentation

GKE Production

Security Hardening

GitOps (ArgoCD)

CI/CD Pipeline

​Next Steps

Overview

Why Binary Authorization?

Architecture

Quick Setup (20 minutes)

Policy Configuration

Policy Modes

Environment-Specific Policies

Image Signing in CI/CD

GitHub Actions Integration

Verification & Troubleshooting

Check Policy Status

View Denials in Logs

Common Issues

Security Best Practices

Compliance & Auditing

SOC 2 / HIPAA Requirements

SLSA Level 3 Compliance

Migration Path

Related Documentation

Next Steps