sc-docker

name	sc-docker
description	Docker-specific security checks — image hardening, secrets in layers, compose security, and runtime configuration
license	MIT
metadata	{"author":"ersinkoc","category":"security","version":"1.0.0"}

SC: Docker Security

Purpose

Performs Docker-specific security analysis covering Dockerfile best practices, secrets exposure in image layers, docker-compose security configuration, runtime security settings, and container image hardening. Extends beyond general IaC scanning with deep Docker expertise.

Activation

Called by sc-orchestrator during Phase 2 when Dockerfile or docker-compose files are detected.

Phase 1: Discovery

File Patterns

**/Dockerfile*, **/docker-compose*, **/.dockerignore,
**/docker/*, **/*.dockerfile

Dockerfile Security Checks

1. Running as Root: Check for missing USER directive after base image.

2. Secrets in Build:

# VULNERABLE: Secret in ENV or ARG
ENV DATABASE_PASSWORD=mysecret
ARG API_KEY=sk_live_abc123
COPY .env /app/.env

# SAFE: Use build secrets (BuildKit)
RUN --mount=type=secret,id=db_password cat /run/secrets/db_password

3. ADD vs COPY:

# RISKY: ADD can auto-extract and fetch URLs
ADD https://example.com/app.tar.gz /app/
ADD . /app/

# SAFE: COPY is explicit
COPY . /app/

4. Missing .dockerignore: Without .dockerignore, sensitive files get copied into the image: .env, .git/, node_modules/, *.pem, *.key

5. Unverified Base Image:

# RISKY: Unverified image
FROM someuser/myimage:latest

# SAFE: Official image with digest
FROM node:18-alpine@sha256:abc123...

Docker Compose Security

# VULNERABLE patterns
services:
  app:
    privileged: true          # Full host access
    network_mode: host        # Shares host network
    pid: host                 # Shares host PID namespace
    volumes:
      - /:/host               # Mounts host root
    cap_add:
      - ALL                   # All capabilities
    env_file:
      - .env                  # Secrets in env file (check .gitignore)

# SAFE patterns
services:
  app:
    read_only: true
    security_opt:
      - no-new-privileges:true
    cap_drop:
      - ALL
    cap_add:
      - NET_BIND_SERVICE      # Only what's needed
    tmpfs:
      - /tmp

Severity Classification

• Critical: Secrets in image layers, privileged mode, host root mount
• High: Running as root, host network/PID, missing .dockerignore with secrets
• Medium: Using latest tag, ADD instead of COPY, missing health check
• Low: Missing resource limits, non-optimal layer ordering

Output Format

Finding: DOCK-{NNN}

• Title: Docker {vulnerability type}
• Severity: Critical | High | Medium | Low
• Confidence: 0-100
• File: file/path:line
• Vulnerability Type: CWE-250 (Excessive Privileges) | CWE-732 (Incorrect Permission)
• Description: {What was found}
• Impact: Container escape, secret exposure, host compromise.
• Remediation: {Specific Dockerfile/compose fix}
• References: https://docs.docker.com/develop/security-best-practices/

Common False Positives

1. Build-stage root — multi-stage builds running as root in build stage but non-root in final
2. CI/CD containers — build containers with elevated privileges for CI tasks
3. Development compose — development overrides with relaxed security