Dockerization

Docker Security Best Practices: Hardened Containers That Pass Audits

Most Docker containers run as root, mount the Docker socket, and use images with hundreds of known CVEs. A single container escape means full host access. We harden your containers with non-root users, read-only filesystems, dropped capabilities, and distroless base images — security practices that pass SOC 2 and PCI audits.

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Why Docker Security Matters

Containers share the host kernel. A container running as root with default capabilities can mount host filesystems, load kernel modules, and escape to the host. Docker's default security posture is permissive by design — it prioritizes compatibility over hardening.

In production, this means every container is a potential lateral movement path for attackers. A compromised web app container can reach the database container on the same network, read environment variables with credentials, and exfiltrate data. Hardening reduces the blast radius of a compromise from "full host access" to "one isolated process."

Our Security Hardening Practices

We apply defense-in-depth across every layer:

  • Non-root user: Every Dockerfile ends with USER appuser — processes run with minimal privileges. Files are owned by root but readable by the app user, preventing the app from modifying its own binaries.
  • Read-only filesystem: read_only: true in Compose, with tmpfs mounts only where the app needs to write (e.g., /tmp, /var/run).
  • Drop capabilities: cap_drop: [ALL] removes all Linux capabilities. We add back only what is needed (rarely anything for web apps).
  • No new privileges: security_opt: [no-new-privileges:true] prevents privilege escalation via setuid binaries.
  • Minimal base images: Distroless or Alpine — fewer packages means fewer CVEs and no shell for attackers to use.
  • Image scanning: Trivy or Grype integrated into CI to block deployments with critical or high CVEs.

Network and Secret Security

Beyond container hardening, we secure the network and secret management:

  • Network segmentation: Separate Docker networks for frontend and backend services. The web server can reach the app, but not the database directly.
  • No Docker socket mounting: Never mount /var/run/docker.sock — it gives full host control.
  • Secrets management: Credentials in Docker secrets or external vault, never in environment variables baked into images. docker secret for Swarm, or env_file with .env files excluded from version control.
  • Content trust: Enable DOCKER_CONTENT_TRUST=1 to verify image signatures.

What You Get

  • Hardened Dockerfiles with non-root users and minimal base images
  • Compose files with read-only filesystems, dropped capabilities, and no-new-privileges
  • Network segmentation between service tiers
  • CI pipeline with Trivy/Grype image scanning and CVE thresholds
  • Security checklist document covering all hardening measures applied
  • Remediation guide for any existing CVEs in your current images

Why Anubiz Engineering

100% async — no calls, no meetings
Delivered in days, not weeks
Full documentation included
Production-grade from day one
Security-first approach
Post-delivery support included

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