AWS RDS Security: Encryption, Authentication, and Isolation

Part of the Cybersecurity Skills Guide — This article is one deep-dive in our complete guide series.

By HADESS Team | February 28, 2026 | Updated: February 28, 2026 | 5 min read

RDS manages the database engine for you, but security configuration is still your responsibility. A misconfigured RDS instance with public access, no encryption, and password-based auth is as vulnerable as an unpatched database on bare metal. Here is how to get the security configuration right.

Encryption at Rest and in Transit

Enable encryption at rest when you create the instance. You cannot enable it after the fact — you have to create an encrypted snapshot, restore from it, and switch over. Use a customer-managed KMS key rather than the default aws/rds key so you can control key policies, rotation, and cross-account access.

Encryption at rest covers the underlying storage, automated backups, read replicas, and snapshots. It uses AES-256 through KMS envelope encryption.

For encryption in transit, enforce SSL/TLS connections. Set the rds.force_ssl parameter to 1 in your parameter group (for PostgreSQL) or use require_secure_transport=ON for MySQL. Download the RDS CA certificate bundle and configure your application to verify the server certificate. Without verification, you are vulnerable to man-in-the-middle attacks even with SSL enabled.

IAM Database Authentication

IAM auth eliminates the need for database passwords. Instead of storing credentials in Secrets Manager or environment variables, your application uses its IAM role to generate a short-lived authentication token. The token expires after 15 minutes, so stolen tokens have a narrow exploitation window.

IAM auth works with MySQL and PostgreSQL on RDS. Enable it on the instance, create a database user mapped to an IAM role, and use the generate-db-auth-token API in your application. The IAM policy grants rds-db:connect on the specific database resource.

The tradeoff: IAM auth has a connection limit of 200 per second. For high-throughput applications, use connection pooling or stick with Secrets Manager-based authentication with automatic rotation.

VPC Isolation

Never make an RDS instance publicly accessible. Place instances in private subnets with no route to an internet gateway. Use a DB subnet group that spans multiple AZs for high availability but only includes private subnets.

Security groups on RDS should allow inbound connections only from the application tier’s security group on the database port. Reference the application security group by ID, not by CIDR block. This way, as the application scales and IPs change, the security group rule still works.

For administrative access, use an SSM Session Manager bastion or RDS Proxy rather than exposing the database to a public-facing jump box.

Audit Logging

Enable database-level audit logging. For PostgreSQL, use the pgAudit extension to log DDL changes, role modifications, and data access patterns. For MySQL, enable the audit log plugin and send output to CloudWatch Logs.

Configure Enhanced Monitoring for OS-level metrics and Performance Insights for query-level visibility. These help detect anomalous database activity like unusual query patterns that might indicate SQL injection or data exfiltration.

Set up Event Subscriptions to get notified about security-relevant changes: parameter group modifications, security group changes, and master password resets.

Next Steps

• Evaluate your database security skills with the assessment tool
• Browse database and cloud security topics in the skills library
• Check compensation benchmarks for cloud database roles with the salary calculator

Related Guides in This Series

• Active Directory Security: Attack Paths and Hardening — HADESS | 2026
• AWS ALB Security: TLS, Authentication, and Access Controls — HADESS | 2026
• AWS CloudTrail: Log Analysis and Security Monitoring — HADESS | 2026

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