Artifact Tampering Risk

# BAD: Docker image built and pushed without signing or attestation
name: Build and Push
on:
  push:
    branches: [main]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      - uses: docker/build-push-action@v5
        with:
          push: true
          tags: ghcr.io/myorg/myapp:latest
          # No signing, no attestation, no SBOM
          # Anyone with registry write access can replace this image

# GOOD: Docker image with cosign signature and SLSA provenance
name: Build and Push
on:
  push:
    branches: [main]
jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      id-token: write  # needed for cosign keyless signing
    steps:
      - uses: actions/checkout@v4
      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      - uses: docker/build-push-action@v5
        id: build
        with:
          push: true
          tags: ghcr.io/myorg/myapp:${{ github.sha }}
      - uses: sigstore/cosign-installer@v3
      - run: cosign sign --yes ghcr.io/myorg/myapp@${{ steps.build.outputs.digest }}