Serving Sensitive Data Securely

TL;DR

Protecting sensitive data requires a layered approach. Use HTTPS, strong authentication and authorisation, limit data exposure, encrypt at rest and in transit, regularly audit access, and keep your systems updated.

Serving Sensitive Data Securely: A Step-by-Step Guide

1. Use HTTPS (SSL/TLS)

• HTTPS encrypts communication between the server and client. This prevents eavesdropping and man-in-the-middle attacks.
• Obtain an SSL/TLS certificate from a trusted Certificate Authority (CA). Let’s Encrypt is a free option: https://letsencrypt.org/
• Configure your web server (e.g., Apache, Nginx) to use the certificate. Example for Nginx:

  server {
    listen 443 ssl;
    ssl_certificate /etc/nginx/ssl/your_domain.crt;
    ssl_certificate_key /etc/nginx/ssl/your_domain.key;
  }
  

• Redirect all HTTP traffic to HTTPS.

Implement Strong Authentication

• Use strong passwords and enforce password complexity requirements (length, special characters, etc.).
• Consider multi-factor authentication (MFA) for an extra layer of security.
• Avoid storing passwords in plain text; use a robust hashing algorithm like bcrypt or Argon2.

Authorisation: Control Access to Data

• Implement role-based access control (RBAC). Users should only have access to the data they need to perform their job.
• Regularly review and update user permissions.
• Use a framework or library that simplifies authorisation management.

Limit Data Exposure

• Only return the necessary data in API responses. Avoid exposing entire database records if only specific fields are required.
• Implement pagination for large datasets to prevent performance issues and reduce the amount of sensitive data transferred at once.
• Sanitise all user inputs to prevent injection attacks (SQL injection, XSS).

Encrypt Data at Rest

• Encrypt sensitive data stored in databases or filesystems.
• Use a strong encryption algorithm like AES-256.
• Manage encryption keys securely; do not store them directly in your application code. Consider using a key management service (KMS).

Encrypt Data in Transit

• As mentioned earlier, HTTPS encrypts data during transmission. Ensure all communication channels are secured with TLS 1.2 or higher.
• If using APIs, ensure API keys and tokens are transmitted securely (e.g., over HTTPS).

Regularly Audit Access Logs

• Monitor access logs for suspicious activity.
• Implement alerting mechanisms to notify you of potential security breaches.
• Review audit logs regularly to identify and address any vulnerabilities.

Keep Systems Updated

• Regularly update your operating system, web server, database software, and all other dependencies with the latest security patches.
• Automate updates whenever possible.
• Use a vulnerability scanner to identify and address any known vulnerabilities in your systems.