SnapOtter/apps/docs/guide/security.md

description

description
Security hardening guide for SnapOtter. Container security, network isolation, Docker secrets, Kubernetes deployment, and compliance artifacts.

Security & Hardening

SnapOtter processes files entirely on your infrastructure. It sends anonymous, content-free product analytics and crash reports by default to help improve the project. It never sends your files, file names, file contents, OCR output, image metadata, or document text. Optional feedback is sent only after a user submits it, only when analytics is enabled, and contact fields are included only with explicit contact consent. An administrator can turn analytics and feedback capture off in one click under Settings > System > Privacy, no rebuild required. File processing always stays inside your container.

The container runs as a dedicated non-root user (snapotter) with all Linux capabilities dropped except the minimum required set. For the full vulnerability disclosure policy and security architecture, see SECURITY.md on GitHub.

Container Hardening

The default docker-compose.yml includes production security hardening. Here is a breakdown of each option and why it matters:

services:
  SnapOtter:
    image: snapotter/snapotter:latest
    ports:
      # Bind to localhost only for internet-facing deployments:
      - "127.0.0.1:1349:1349"
    volumes:
      - SnapOtter-data:/data
      - SnapOtter-workspace:/tmp/workspace
    environment:
      - AUTH_ENABLED=true
      - DEFAULT_PASSWORD=change-me-immediately
      - RATE_LIMIT_PER_MIN=1000
      - DATABASE_URL=postgres://snapotter:snapotter@postgres:5432/snapotter
      - REDIS_URL=redis://redis:6379
    depends_on:
      postgres:
        condition: service_healthy
      redis:
        condition: service_healthy

    # --- Resource limits ---
    mem_limit: 6g            # Prevents runaway memory from crashing the host
    memswap_limit: 6g        # No swap - fail fast instead of degrading the host
    cpus: 4                  # Cap CPU usage to 4 cores
    pids_limit: 512          # Prevents fork bombs

    # --- Capability restrictions ---
    cap_drop:
      - ALL                  # Drop ALL Linux capabilities first
    cap_add:
      - CHOWN                # Needed for volume permission setup
      - SETUID               # Needed for gosu privilege drop (root -> snapotter)
      - SETGID               # Needed for gosu privilege drop
      - DAC_OVERRIDE         # Needed for volume permission setup
      - FOWNER               # Needed for volume permission setup

    # --- Logging ---
    logging:
      driver: json-file
      options:
        max-size: "50m"      # Rotate logs at 50 MB
        max-file: "5"        # Keep 5 rotated log files

    # --- Health check ---
    healthcheck:
      test: ["CMD", "curl", "-sf", "--max-time", "5", "http://localhost:1349/api/v1/health"]
      interval: 30s
      timeout: 5s
      start_period: 60s
      retries: 3

    shm_size: "2gb"          # Required for Python ML shared memory
    restart: unless-stopped

  postgres:
    image: postgres:17-alpine
    environment:
      POSTGRES_USER: snapotter
      POSTGRES_PASSWORD: snapotter
      POSTGRES_DB: snapotter
    volumes:
      - SnapOtter-pgdata:/var/lib/postgresql/data
    restart: unless-stopped
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U snapotter"]
      interval: 10s
      timeout: 5s
      retries: 12
      start_period: 15s

  redis:
    image: redis:8-alpine
    command: ["redis-server", "--maxmemory-policy", "noeviction", "--appendonly", "yes"]
    volumes:
      - SnapOtter-redisdata:/data
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 10s
      timeout: 5s
      retries: 12
      start_period: 10s

volumes:
  SnapOtter-data:
  SnapOtter-workspace:
  SnapOtter-pgdata:
  SnapOtter-redisdata:

Why no-new-privileges Is Not Set

security_opt: [no-new-privileges:true] is intentionally omitted. The entrypoint starts as root to fix volume ownership, then drops to the snapotter user via gosu, which requires setuid. Once the privilege drop completes, the process runs as snapotter with all capabilities except the five listed above removed.

If you use Kubernetes or Docker's --user flag to run as non-root directly (bypassing gosu), no-new-privileges is safe to enable.

Why read_only Is Not Set

read_only: true is not set because PUID/PGID remapping writes to /etc/passwd and /etc/group at startup. If you use Docker's --user flag or Kubernetes runAsUser instead of PUID/PGID, you can safely enable a read-only root filesystem.

Network Isolation

During normal operation, the container makes zero outbound network connections. All file processing happens locally using bundled libraries.

Browser  -->  Reverse Proxy (TLS)  -->  SnapOtter container  -->  (nothing)

The only exception is AI model downloads: when a user installs an AI feature bundle through the UI, the container downloads model files from GitHub Releases and PyPI. These downloads happen once per bundle and are stored in the /data volume.

Firewall recommendations:

Scenario	Outbound rule
Air-gapped (no AI)	Block all outbound traffic from the container
AI bundles needed	Allow HTTPS to github.com, objects.githubusercontent.com, pypi.org, files.pythonhosted.org during install, then block
After AI install	Block all outbound traffic - models are cached locally

For reverse proxy configuration (Nginx, Traefik, Caddy, Cloudflare Tunnels), see the Deployment guide.

Docker Secrets

For production deployments, avoid passing secrets as plain-text environment variables. The entrypoint supports Docker's _FILE convention: mount a secret as a file and set the corresponding _FILE variable to its path.

Supported secrets:

Variable	_FILE equivalent
DEFAULT_PASSWORD	DEFAULT_PASSWORD_FILE
COOKIE_SECRET	COOKIE_SECRET_FILE
OIDC_CLIENT_SECRET	OIDC_CLIENT_SECRET_FILE
S3_ACCESS_KEY_ID	S3_ACCESS_KEY_ID_FILE
S3_SECRET_ACCESS_KEY	S3_SECRET_ACCESS_KEY_FILE
SNAPOTTER_LICENSE_KEY	SNAPOTTER_LICENSE_KEY_FILE

Example with Docker Compose secrets:

services:
  SnapOtter:
    image: snapotter/snapotter:latest
    environment:
      - AUTH_ENABLED=true
      - DEFAULT_USERNAME=admin
      - DEFAULT_PASSWORD_FILE=/run/secrets/snapotter_password
      - COOKIE_SECRET_FILE=/run/secrets/cookie_secret
    secrets:
      - snapotter_password
      - cookie_secret

secrets:
  snapotter_password:
    file: ./secrets/snapotter_password.txt
  cookie_secret:
    file: ./secrets/cookie_secret.txt

::: tip Docker Compose secrets (without Swarm) require Compose v2.23 or later. :::

Kubernetes Deployment

The entrypoint detects when the container is already running as non-root (e.g., via Kubernetes runAsUser) and skips the gosu privilege drop automatically. In that case it cannot chown the mounted volumes itself, so it verifies they are writable and exits early with actionable guidance if they are not — see Storage permissions for fsGroup and foreign-UID setups (TrueNAS, OpenShift).

Recommended Pod SecurityContext:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: snapotter
spec:
  replicas: 1
  selector:
    matchLabels:
      app: snapotter
  template:
    metadata:
      labels:
        app: snapotter
    spec:
      securityContext:
        runAsNonRoot: true
        runAsUser: 999
        runAsGroup: 999
        fsGroup: 999
      containers:
        - name: snapotter
          image: snapotter/snapotter:latest
          ports:
            - containerPort: 1349
          securityContext:
            allowPrivilegeEscalation: false
            capabilities:
              drop: [ALL]
          resources:
            requests:
              cpu: "1"
              memory: 2Gi
            limits:
              cpu: "4"
              memory: 6Gi
          livenessProbe:
            httpGet:
              path: /api/v1/health
              port: 1349
            initialDelaySeconds: 60
            periodSeconds: 30
            timeoutSeconds: 5
          readinessProbe:
            httpGet:
              path: /api/v1/health
              port: 1349
            initialDelaySeconds: 10
            periodSeconds: 10
            timeoutSeconds: 5
          volumeMounts:
            - name: data
              mountPath: /data
            - name: workspace
              mountPath: /tmp/workspace
      volumes:
        - name: data
          persistentVolumeClaim:
            claimName: snapotter-data
        - name: workspace
          emptyDir:
            medium: Memory
            sizeLimit: 2Gi

Since runAsUser: 999 is set at the pod level, the entrypoint skips gosu entirely. This allows allowPrivilegeEscalation: false and drop: [ALL] capabilities without conflict.

For resource sizing, see Hardware Requirements.

Backup and Recovery

Persistent state is split across two volumes:

Volume	Contents	Critical?
SnapOtter-pgdata	PostgreSQL database (users, settings, pipelines, jobs, audit log)	Yes
/data (app volume)	User-uploaded files, AI models, Python venv	Partially (see below)

Within the /data volume:

Path	Contents	Critical?
/data/uploads/, /data/outputs/	User files and processing results	Yes
/data/ai/	Downloaded AI model files	No (re-downloadable)
/data/venv/	Python virtual environment	No (rebuilt on start)

Database backup

Use pg_dump to back up the database while the stack is running:

# Dump the database
docker exec SnapOtter-postgres pg_dump -U snapotter snapotter > backup.sql

# Restore into a fresh database
cat backup.sql | docker exec -i SnapOtter-postgres psql -U snapotter snapotter

Alternatively, stop the stack and snapshot the SnapOtter-pgdata volume:

docker compose down
docker run --rm -v SnapOtter-pgdata:/data -v $(pwd)/backup:/backup \
  alpine tar czf /backup/snapotter-pgdata.tar.gz -C /data .

User files backup

# Snapshot the app data volume (excluding re-downloadable AI models)
docker run --rm -v SnapOtter-data:/data -v $(pwd)/backup:/backup \
  alpine tar czf /backup/snapotter-files.tar.gz \
    --exclude='ai' --exclude='venv' -C /data .

AI models total up to about 24 GB across all bundles. Since they are re-downloadable, exclude /data/ai/ and /data/venv/ from backups to save space. Only the database and user files are critical.

Compliance Artifacts

Each SnapOtter release includes the following security artifacts:

Artifact	Format	Where to find it
SBOM (CycloneDX)	JSON	GitHub Release asset: snapotter-v{version}-sbom.cdx.json
SBOM (SPDX)	JSON	GitHub Release asset: snapotter-v{version}-sbom.spdx.json
Vulnerability scan	Trivy JSON	GitHub Release asset: snapotter-v{version}-trivy.json
Vulnerability scan	SARIF	GitHub Security tab
Static analysis	CodeQL (JS/TS + Python)	GitHub Security tab, runs weekly + per PR
Dependency review	GitHub native	Per-PR check, fails on high-severity additions
Python dependency audit	pip-audit	CI run log on every push
Security policy	Markdown	SECURITY.md in the repository
Dependency updates	Dependabot	Automated weekly PRs for npm, pip, Docker, Actions

Running your own scan:

Download the SBOM from the release and scan it with your preferred tool:

# Scan with Grype using the CycloneDX SBOM
grype sbom:snapotter-v1.17.2-sbom.cdx.json

# Scan with Trivy using the SPDX SBOM
trivy sbom snapotter-v1.17.2-sbom.spdx.json

# Scan the Docker image directly
trivy image snapotter/snapotter:1.17.2

::: info The SBOM and vulnerability scan reflect the exact image published for that release. AI model bundles installed after deployment are not included in the SBOM since they are downloaded at runtime. :::