AWS Security: Best Practices

Security is the highest priority at AWS. For a DevOps engineer, understanding how to secure infrastructure is as important as knowing how to build it. This guide covers the fundamental pillars of AWS security.

🤝 The Shared Responsibility Model

Before securing your resources, you must understand the "line of demarcation" between AWS and the customer.

• AWS: Responsible for the underlying infrastructure (the data centers, the hardware, and the software that runs the cloud).
• Customer: Responsible for everything they put into the cloud (data, OS configuration, IAM policies, and encryption).

🔑 The Identity Pillar (IAM)

Identity is the new perimeter. Use these rules to prevent unauthorized access:

• Root Account Hygiene: Never use the root account for daily tasks. Enable MFA immediately and lock away the credentials.
• Principle of Least Privilege: Grant users only the permissions they need to do their job—nothing more.
• Enforce MFA: Multi-Factor Authentication should be mandatory for all users and roles with programmatic access.
• Rotate Credentials: Change passwords and rotate IAM access keys every 90 days.

🛡️ Infrastructure & Data Protection

1. Network Isolation

Keep your application resources in Private Subnets. Use a NAT Gateway for outbound traffic and restrict inbound access using Security Groups (only open ports 80/443 for web, and 22 for SSH via a VPN or Bastion host).

2. Encryption Everywhere

• Encryption at Rest: Enable encryption for S3 buckets, EBS volumes, and RDS databases using AWS KMS (Key Management Service).
• Encryption in Transit: Always use TLS/SSL (HTTPS) for your applications. Use AWS Certificate Manager (ACM) to provision and manage your SSL certificates.

🕵️ Detective Controls (Logging & Auditing)

You cannot protect what you cannot see. Use these services to maintain visibility:

• AWS CloudTrail: Records every API call made in your account (Who did what, when, and from where?).
• Amazon CloudWatch: Monitors metrics and logs in real-time. Set up Alarms to notify you of suspicious spikes in traffic or resource usage.
• AWS Config: Tracks the history of your resource configurations to ensure they haven't drifted from your security baseline.

✅ Master Security Checklist

[!TIP] Use AWS Trusted Advisor AWS Trusted Advisor provides a "Security" category that automatically scans your account for common security gaps (like open ports or public S3 buckets) and gives you actionable recommendations for free.