Implementing Gcp Binary Authorization

---
name: implementing-gcp-binary-authorization
description: Use when implement GCP Binary Authorization to enforce deploy-time security
  controls that ensure only trusted, attested container images are deployed to Google
  Kubernetes Engine and Cloud Run. Use when implementing gcp binary authorization
  to enforce deploy-time security controls that.
domain: cybersecurity
subdomain: cloud-security
tags:
- gcp
- binary-authorization
- container-security
- supply-chain
- gke
- cloud-run
- attestation
- software-integrity
version: '1.0'
author: oyi77
license: Apache-2.0
nist_csf:
- PR.IR-01
- ID.AM-08
- GV.SC-06
- DE.CM-01
category: cybersecurity
---


# Implementing GCP Binary Authorization

## Overview

Binary Authorization is a Google Cloud deploy-time security control that ensures only trusted container images are deployed on GKE or Cloud Run. It works through a policy-based model where images must have cryptographic attestations confirming they passed predefined requirements such as vulnerability scans, code reviews, or build pipeline verification. Continuous validation (CV) monitors running pods against policies and logs violations.


## When to Use
**Trigger phrases:**
- "implementing gcp binary authorization"
- "Implement GCP Binary Authorization to enforce deploy-time security controls that"


- When deploying or configuring implementing gcp binary authorization 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

- GCP project with Binary Authorization API enabled
- GKE cluster or Cloud Run service
- Container Analysis API enabled
- KMS keys for attestation signing
- Cloud Build or external CI/CD pipeline

## Enable Binary Authorization

```bash
# Enable required APIs
gcloud services enable binaryauthorization.googleapis.com
gcloud services enable containeranalysis.googleapis.com
gcloud services enable container.googleapis.com

# Enable Binary Authorization on GKE cluster
gcloud container clusters update CLUSTER_NAME \
  --enable-binauthz \
  --zone us-central1-a
```

## Create Attestor

This section covers create attestor for implementing gcp binary authorization.

- Ensure all prerequisites are met before proceeding
- Follow the documented workflow steps in sequence
- Record results and any anomalies encountered during this phase
### Create a KMS key for signing

```bash
# Create keyring
gcloud kms keyrings create binauthz-keyring \
  --location global

# Create signing key
gcloud kms keys create attestor-key \
  --keyring binauthz-keyring \
  --location global \
  --algorithm ec-sign-p256-sha256 \
  --purpose asymmetric-signing
```

### Create Container Analysis note

```bash
cat > /tmp/note.json << 'EOF'
{
  "attestation": {
    "hint": {
      "humanReadableName": "Production Build Attestor"
    }
  }
}
EOF

curl -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $(gcloud auth print-access-token)" \
  "https://containeranalysis.googleapis.com/v1/projects/PROJECT_ID/notes/?noteId=prod-build-note" \
  -d @/tmp/note.json
```

### Create the attestor

```bash
gcloud container binauthz attestors create prod-build-attestor \
  --attestation-authority-note=prod-build-note \
  --attestation-authority-note-project=PROJECT_ID

# Add KMS key to attestor
gcloud container binauthz attestors public-keys add \
  --attestor=prod-build-attestor \
  --keyversion-project=PROJECT_ID \
  --keyversion-location=global \
  --keyversion-keyring=binauthz-keyring \
  --keyversion-key=attestor-key \
  --keyversion=1
```

## Configure Policy

This section covers configure policy for implementing gcp binary authorization.

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

```yaml
# binauthz-policy.yaml
admissionWhitelistPatterns:
  - namePattern: "gcr.io/google_containers/*"
  - namePattern: "gcr.io/google-containers/*"
  - namePattern: "k8s.gcr.io/**"
  - namePattern: "gke.gcr.io/**"
  - namePattern: "gcr.io/stackdriver-agents/*"
defaultAdmissionRule:
  evaluationMode: REQUIRE_ATTESTATION
  enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
  requireAttestationsBy:
    - projects/PROJECT_ID/attestors/prod-build-attestor
globalPolicyEvaluationMode: ENABLE
```

```bash
gcloud container binauthz policy import binauthz-policy.yaml
```

### Per-cluster rules

```yaml
admissionWhitelistPatterns:
  - namePattern: "gcr.io/google_containers/*"
clusterAdmissionRules:
  us-central1-a.production-cluster:
    evaluationMode: REQUIRE_ATTESTATION
    enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
    requireAttestationsBy:
      - projects/PROJECT_ID/attestors/prod-build-attestor
  us-central1-a.staging-cluster:
    evaluationMode: ALWAYS_ALLOW
    enforcementMode: DRYRUN_AUDIT_LOG_ONLY
defaultAdmissionRule:
  evaluationMode: ALWAYS_DENY
  enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
```

## Create Attestations

This section covers create attestations for implementing gcp binary authorization.

- Ensure all prerequisites are met before proceeding
- Follow the documented workflow steps in sequence
- Record results and any anomalies encountered during this phase
### Attest an image after successful build

```bash
# Get image digest
IMAGE_DIGEST=$(gcloud container images describe \
  gcr.io/PROJECT_ID/my-app:latest \
  --format='get(image_summary.digest)')

# Create attestation
gcloud container binauthz attestations sign-and-create \
  --artifact-url="gcr.io/PROJECT_ID/my-app@${IMAGE_DIGEST}" \
  --attestor="prod-build-attestor" \
  --attestor-project="PROJECT_ID" \
  --keyversion-project="PROJECT_ID" \
  --keyversion-location="global" \
  --keyversion-keyring="binauthz-keyring" \
  --keyversion-key="attestor-key" \
  --keyversion="1"
```

### Cloud Build integration

```yaml
# cloudbuild.yaml
steps:
  - name: 'gcr.io/cloud-builders/docker'
    args: ['build', '-t', 'gcr.io/$PROJECT_ID/my-app:$SHORT_SHA', '.']

  - name: 'gcr.io/cloud-builders/docker'
    args: ['push', 'gcr.io/$PROJECT_ID/my-app:$SHORT_SHA']

  # Vulnerability scanning
  - name: 'gcr.io/cloud-builders/gcloud'
    entrypoint: 'bash'
    args:
      - '-c'
      - |
        gcloud artifacts docker images scan \
          gcr.io/$PROJECT_ID/my-app:$SHORT_SHA \
          --format='value(response.scan)'

  # Create attestation after successful scan
  - name: 'gcr.io/cloud-builders/gcloud'
    entrypoint: 'bash'
    args:
      - '-c'
      - |
        IMAGE_DIGEST=$(gcloud container images describe \
          gcr.io/$PROJECT_ID/my-app:$SHORT_SHA \
          --format='get(image_summary.digest)')
        gcloud container binauthz attestations sign-and-create \
          --artifact-url="gcr.io/$PROJECT_ID/my-app@$${IMAGE_DIGEST}" \
          --attestor="prod-build-attestor" \
          --attestor-project="$PROJECT_ID" \
          --keyversion-project="$PROJECT_ID" \
          --keyversion-location="global" \
          --keyversion-keyring="binauthz-keyring" \
          --keyversion-key="attestor-key" \
          --keyversion="1"
```

## Continuous Validation

```bash
# Enable CV on a GKE cluster
gcloud container clusters update CLUSTER_NAME \
  --enable-binauthz-monitoring \
  --zone us-central1-a
```

### Monitor CV violations in Cloud Logging

```
resource.type="k8s_cluster"
logName="projects/PROJECT_ID/logs/binaryauthorization.googleapis.com%2Fcontinuous_validation"
```

## Verification and Testing

This section covers verification and testing for implementing gcp binary authorization.

- Ensure all prerequisites are met before proceeding
- Follow the documented workflow steps in sequence
- Record results and any anomalies encountered during this phase
### Test deployment of unattested image

```bash
# This should be blocked
kubectl run test-unapproved \
  --image=docker.io/library/nginx:latest

# Verify the pod was denied
kubectl get events --field-selector reason=FailedCreate
```

### Verify attestation exists

```bash
gcloud container binauthz attestations list \
  --attestor=prod-build-attestor \
  --attestor-project=PROJECT_ID
```

## Break-Glass Override

For emergency deployments bypassing Binary Authorization:

```yaml
apiVersion: v1
kind: Pod
metadata:
  name: emergency-pod
  labels:
    image-policy.k8s.io/break-glass: "true"
  annotations:
    alpha.image-policy.k8s.io/break-glass: "Emergency deployment - ticket INC-12345"
spec:
  containers:
    - name: emergency
      image: gcr.io/PROJECT_ID/emergency-fix:latest
```

## When NOT to Use

- You need to test the implementation (use performing-* skills)
- Task is about configuring existing tools (use configuring-* skills)
- You need to analyze security events (use analyzing-* skills)
- Task is about building detection rules (use building-* skills)
- You don't have access to the target environment
- Task requires vendor-specific expertise (consult vendor docs)


## Red Flags

- Performing actions without explicit written authorization from the asset owner
- Testing against production systems without a defined scope and rules of engagement
- Modifying cloud IAM policies or security groups without approval
- Exposing cloud credentials or secrets in logs or reports
- Running scans that generate excessive API calls and trigger billing alerts

## Verification

- All steps executed successfully against a test environment before production use
- Output documented with screenshots or logs demonstrating expected behavior
- Cloud resource changes reverted or documented as intentional
- IAM policies reviewed for least-privilege compliance after testing
- No residual test resources left running (cost and security check)

## References

- GCP Binary Authorization: https://cloud.google.com/binary-authorization/docs
- SLSA Framework: https://slsa.dev
- Sigstore/Cosign for container signing
- Google Software Supply Chain Security Best Practices

## Process

1. Analyze the task requirements
2. Apply domain expertise
3. Verify output quality

## Anti-Rationalization Table

| 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. |