| description | Scans Docker containers and images for security vulnerabilities |
| shortcut | dss |
| category | security |
| difficulty | intermediate |
| estimated_time | 5-10 minutes |
Docker Security Scan
Comprehensively scans Docker containers and images for vulnerabilities, misconfigurations, and security best practices violations. Identifies CVEs in base images and dependencies, insecure configurations, exposed secrets, and privilege escalation risks.
What This Command Does
Complete Container Security Analysis:
- Scans images for known CVEs (vulnerabilities in OS packages and dependencies)
- Detects insecure Dockerfile configurations
- Identifies exposed secrets (API keys, passwords, tokens)
- Checks for privileged containers and excessive permissions
- Validates security best practices (non-root user, minimal base image)
- Analyzes running containers for runtime security issues
Output: Detailed security report with severity-rated findings and remediation steps
Time: 5-10 minutes per image/container
When to Use This Command
Perfect For:
- Pre-deployment container security validation
- CI/CD pipeline security gates
- Production container audits
- Kubernetes pod security review
- Docker Compose security assessment
Use This When:
- Building new container images
- Before deploying to production
- After updating base images
- Regular security audits (weekly/monthly)
- Investigating security incidents
Usage
/docker-security-scan myapp:latest
/docker-security-scan --container myapp-prod
/docker-security-scan --all-images
/docker-security-scan myapp:latest --verbose
/docker-security-scan myapp:latest --output report.md
Shortcut:
/dss myapp:latest
What Gets Scanned
1. Image Vulnerabilities (CVEs)
Scans For:
- Operating system package vulnerabilities
- Application dependency vulnerabilities
- Known exploits in installed software
- Outdated packages with security patches available
Example Findings:
CRITICAL: CVE-2024-12345 in openssl
Package: openssl 1.1.1k
Severity: Critical (CVSS 9.8)
Impact: Remote code execution via crafted TLS handshake
Fixed in: openssl 1.1.1w
Remediation:
FROM ubuntu:22.04 # Update base image
RUN apt-get update && apt-get upgrade -y openssl
Example Output:
Image: myapp:latest
Base: node:16 (debian:bullseye)
Vulnerabilities Found: 47
Critical: 3
High: 12
Medium: 18
Low: 14
Top Critical CVEs:
1. CVE-2024-12345 (openssl) - RCE via TLS
2. CVE-2024-23456 (curl) - Buffer overflow
3. CVE-2024-34567 (libc6) - Privilege escalation
2. Dockerfile Security Issues
Checks:
- Running as root user
- Hardcoded secrets in layers
- Exposed sensitive ports
- Unnecessary packages installed
- Missing health checks
- Outdated base images
Example Findings:
# BAD: Running as root
FROM node:16
WORKDIR /app
COPY . .
RUN npm install
CMD ["node", "server.js"] # Runs as root!
# GOOD: Non-root user
FROM node:16
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
USER node # Drop to non-root user
CMD ["node", "server.js"]
# BAD: Hardcoded secrets
FROM node:16
ENV DATABASE_PASSWORD="MySecretPassword123" # Exposed in image layers!
# GOOD: Runtime secrets
FROM node:16
# Pass secrets at runtime via environment variables or secrets management
CMD ["node", "server.js"]
# BAD: Unnecessary packages
FROM ubuntu:latest
RUN apt-get update && apt-get install -y \
build-essential \
python3 \
curl \
wget \
vim \
emacs \
git \
# Unnecessary packages increase attack surface!
# GOOD: Minimal image
FROM node:16-alpine # Minimal base image
RUN apk add --no-cache curl # Only necessary packages
3. Container Runtime Configuration
Scans For:
- Privileged containers (
--privileged)
- Dangerous capabilities (CAP_SYS_ADMIN, CAP_NET_ADMIN)
- Host network mode
- Mounted sensitive host paths
- No resource limits (CPU, memory)
Example Findings:
docker run --privileged myapp:latest
docker run --cap-drop=ALL --cap-add=NET_BIND_SERVICE myapp:latest
docker run --network=host myapp:latest
docker run --network=bridge myapp:latest
docker run -v /etc:/host-etc myapp:latest
docker run -v /app/data:/data:ro myapp:latest
4. Exposed Secrets
Detects:
- API keys in environment variables
- Passwords in image layers
- Private keys in container filesystem
- Database credentials
- OAuth tokens
Example Findings:
docker run -e AWS_SECRET_KEY="wJalrXUtnFEMI/K7MDENG/..." myapp:latest
docker run --env-file /secure/secrets.env myapp:latest
5. Network Exposure
Checks:
- Exposed ports (especially dangerous: 22 SSH, 3306 MySQL, 6379 Redis)
- Port mapping to 0.0.0.0 (all interfaces)
- Missing network segmentation
Example Findings:
docker run -p 0.0.0.0:5432:5432 postgres:latest
docker run -p 127.0.0.1:5432:5432 postgres:latest
docker network create app-network
docker run --network=app-network postgres:latest
6. Resource Limits
Checks for:
- Missing memory limits (risk of OOM killing host)
- Missing CPU limits (risk of resource starvation)
- No restart policy (availability)
Example Findings:
docker run myapp:latest
docker run \
--memory=512m \
--cpus=1.0 \
--restart=unless-stopped \
myapp:latest
Example: Full Scan Output
$ /docker-security-scan myapp:latest
Docker Security Scan
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Image: myapp:latest
Size: 1.2 GB
️ Base: node:16 (debian:bullseye)
Created: 2025-10-05
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
CRITICAL ISSUES (Fix Immediately)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1. Running as Root User
Dockerfile:15
Severity: Critical
USER root
️ Impact: If container is compromised, attacker has root access
Fix:
RUN addgroup -S appgroup && adduser -S appuser -G appgroup
USER appuser
2. Hardcoded Database Password
Dockerfile:8
Severity: Critical
ENV DB_PASSWORD="MySecretPassword123"
️ Impact: Password visible in image layers, docker inspect
Fix:
- Remove from Dockerfile
- Pass at runtime: docker run -e DB_PASSWORD="$SECRET" myapp:latest
- Use Docker secrets or Kubernetes secrets
3. CVE-2024-12345 in openssl
Package: openssl 1.1.1k
Severity: Critical (CVSS 9.8)
Vulnerability: Remote code execution via TLS handshake
Fix:
FROM node:16-bullseye
RUN apt-get update && apt-get upgrade -y openssl
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
️ HIGH SEVERITY ISSUES
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
4. Privileged Container Mode
Severity: High
docker run --privileged myapp:latest
️ Impact: Container can access all host devices, escape container
Fix:
- Remove --privileged flag
- Use specific capabilities: --cap-add=NET_BIND_SERVICE
5. Host Network Mode
Severity: High
docker run --network=host myapp:latest
️ Impact: Container can access all host network interfaces
Fix:
docker run --network=bridge myapp:latest
6. Mounted Sensitive Host Path
Severity: High
-v /etc:/host-etc
️ Impact: Container can read/modify host /etc files
Fix:
- Remove mount if not needed
- Use specific paths: -v /app/config:/config:ro
- Mount read-only: :ro
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
MEDIUM SEVERITY ISSUES
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
7. No Health Check Defined
Severity: Medium
HEALTHCHECK instruction missing
️ Impact: Container may be running but unhealthy
Fix:
HEALTHCHECK --interval=30s --timeout=3s \
CMD curl -f http://localhost:3000/health || exit 1
8. Outdated Base Image
Severity: Medium
FROM node:16 (2022-04-20)
️ Impact: Missing 18 months of security patches
Fix:
FROM node:20-alpine
9. No Resource Limits
Severity: Medium
No --memory or --cpus limits
️ Impact: Container can consume all host resources
Fix:
docker run --memory=512m --cpus=1.0 myapp:latest
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
VULNERABILITY SUMMARY
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Total Issues: 47
Critical: 3 (Fix immediately)
High: 12 (Fix within 1 week)
Medium: 18 (Fix within 1 month)
Low: 14 (Best practices)
CVE Summary:
Critical: 3 CVEs
High: 12 CVEs
Medium: 18 CVEs
Low: 14 CVEs
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
RECOMMENDED ACTIONS
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Priority 1 (Immediate):
Add non-root user (2 hours)
Remove hardcoded secrets (1 hour)
Update base image (30 min)
Priority 2 (This Week):
Remove privileged mode (1 hour)
Fix host network usage (2 hours)
Review volume mounts (2 hours)
Priority 3 (This Month):
Add health checks (1 hour)
Set resource limits (30 min)
Update all dependencies (3 hours)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
SECURITY BEST PRACTICES
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Use minimal base images (alpine, distroless)
Run as non-root user
Don
Secure Dockerfile Template
# SECURE DOCKERFILE TEMPLATE
# Use minimal, specific base image (not :latest)
FROM node:20-alpine AS build
# Set working directory
WORKDIR /app
# Copy dependency files first (better caching)
COPY package*.json ./
# Install dependencies
RUN npm ci --only=production \
&& npm cache clean --force
# Copy application code
COPY . .
# Build application (if needed)
RUN npm run build
# ===== Production Stage =====
FROM node:20-alpine
# Add metadata
LABEL maintainer="[email protected]" \
version="1.0.0" \
description="MyApp production image"
# Install security updates
RUN apk update && apk upgrade && rm -rf /var/cache/apk/*
# Create non-root user
RUN addgroup -S appgroup && adduser -S appuser -G appgroup
# Set working directory
WORKDIR /app
# Copy built application from build stage
COPY --from=build --chown=appuser:appgroup /app/dist ./dist
COPY --from=build --chown=appuser:appgroup /app/node_modules ./node_modules
# Switch to non-root user
USER appuser
# Expose port (document only, not publish)
EXPOSE 3000
# Add health check
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
CMD node healthcheck.js || exit 1
# Run application
CMD ["node", "dist/server.js"]
Secure Docker Run Command
docker run \
--name myapp \
--read-only \
--tmpfs /tmp \
--cap-drop=ALL \
--cap-add=NET_BIND_SERVICE \
--security-opt=no-new-privileges:true \
--memory=512m \
--cpus=1.0 \
--restart=unless-stopped \
--network=app-network \
-p 127.0.0.1:3000:3000 \
-e NODE_ENV=production \
--env-file /secure/secrets.env \
myapp:1.0.0
CI/CD Integration
GitHub Actions Example
name: Docker Security Scan
on: [push, pull_request]
jobs:
security-scan:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- name: Build Docker image
run: docker build -t myapp:${{ github.sha }} .
- name: Run Security Scan
run: /docker-security-scan myapp:${{ github.sha }} --output report.md
- name: Upload Report
uses: actions/upload-artifact@v3
with:
name: security-report
path: report.md
- name: Fail on Critical Issues
Related Commands
/security-scan-quick - General application security scan/api-security-audit - API-specific security testing/crypto-audit - Cryptography review
Support
Found container vulnerabilities?
- Fix critical issues immediately (root user, secrets, CVEs)
- For remediation help: Ask Security Auditor Expert
- For Docker best practices: Consult Docker security documentation
- Test fixes: Re-run
/docker-security-scan after changes
Time Investment: 5-10 minutes per scan
Value: Prevent container escape, data breaches, and production compromises
Scan containers early. Fix vulnerabilities fast. Deploy securely.
