SecureCodeReviews

Node.js Security Guide

Node.js is a powerful platform for building scalable web applications, but its flexibility can expose apps to a wide range of security risks. This guide covers essential Node.js security best practices, common vulnerabilities, and actionable steps to secure your applications.

1. Keep Dependencies Up to Date

  • Use npm audit and npm outdated to identify vulnerable packages.
  • Regularly update dependencies and remove unused packages.
  • Prefer well-maintained libraries with active security support.

2. Validate and Sanitize User Input

  • Always validate input on the server side using libraries like joi or zod.
  • Sanitize input to prevent injection attacks (SQL, NoSQL, command, etc.).
  • Use allow-lists (not block-lists) for input validation.

3. Prevent Injection Attacks

  • Use parameterized queries for SQL/NoSQL databases (e.g., Mongoose, Sequelize).
  • Never construct database queries or shell commands from untrusted input.
  • Escape user input where necessary.

4. Secure Authentication & Authorization

  • Use strong password hashing (e.g., bcrypt).
  • Implement multi-factor authentication (MFA) for sensitive actions.
  • Use secure, signed JWTs or session cookies with httpOnly and secure flags.
  • Enforce role-based access control (RBAC) for APIs and admin routes.

5. Protect Against Cross-Site Scripting (XSS)

  • Escape output in templates and APIs.
  • Use libraries like DOMPurify for sanitizing HTML.
  • Set Content Security Policy (CSP) headers.

6. Prevent Cross-Site Request Forgery (CSRF)

  • Use CSRF tokens for state-changing requests (e.g., csurf middleware).
  • Set SameSite cookies where possible.

7. Secure HTTP Headers

  • Set security headers: Strict-Transport-Security, X-Frame-Options, X-Content-Type-Options, Referrer-Policy, Permissions-Policy, Content-Security-Policy.
  • Use libraries like helmet to automate header management.

8. Handle Errors Securely

  • Never expose stack traces or internal error details to users.
  • Log errors securely and monitor for suspicious activity.

9. Secure File Uploads

  • Validate file type, size, and content.
  • Store uploads outside the web root and scan for malware.
  • Rename files to avoid path traversal and overwrites.

10. Use HTTPS Everywhere

  • Enforce HTTPS using HSTS headers.
  • Redirect all HTTP traffic to HTTPS.
  • Never transmit sensitive data over plain HTTP.

11. Environment Variables & Secrets

  • Never commit secrets or credentials to source control.
  • Use environment variables for configuration and secrets.
  • Rotate secrets regularly and restrict access.

12. Monitor & Audit

  • Enable logging and monitor for anomalies.
  • Use tools like winston or pino for structured logging.
  • Set up alerting for suspicious activity.

13. Common Node.js Vulnerabilities

  • Prototype Pollution
  • Denial of Service (DoS)
  • Insecure Deserialization
  • Directory Traversal
  • Untrusted Code Execution (eval, Function)
  • Insecure Regular Expressions (ReDoS)

14. Recommended Security Tools

  • helmet — Secure HTTP headers
  • csurf — CSRF protection
  • joi — Input validation
  • zod — Input validation
  • npm audit — Dependency vulnerability scanner
  • winston — Logging
  • pino — Logging
  • Snyk — Vulnerability scanning

15. Further Reading

Need a professional Node.js security review? Contact our team for a detailed assessment and secure code audit.