Complete SAA-C03 Amazon Web Services Materials

The best practice to securely provide short-term access to AWS resources, such as Amazon S3, without using long-term credentials, is to use AWS Security Token Service (STS). According to the AWS IAM Best Practices and the Security Pillar of the AWS Well-Architected Framework, temporary credentials should always be used over long-term credentials when possible.

From AWS IAM Documentation:

“Use temporary credentials (IAM roles and AWS STS) instead of long-term access keys. Temporary security credentials are short-term, automatically expire, and are retrieved using AWS STS.”

(Source: IAM Best Practices – IAM User Guide)

Option D outlines the use of a trust relationship and assume-role mechanism via AWS STS. This allows the on-premises application to request temporary, scoped-down credentials to upload files to S3 securely. This approach is:

Secure – Uses short-lived credentials with least privilege

Scalable – No need for EC2 or VPN tunnels

Low Operational Overhead – No infrastructure to maintain

AWS-Recommended – Aligned with security best practices

In contrast:

Option A uses long-term credentials, which is a security risk.

Option B requires additional infrastructure (EC2, VPN), increasing complexity and cost.

Option C relies on IP-based access, which is insecure and not a form of identity-based authentication.

In Amazon EKS, Kubernetes stores objects such as Secrets in the cluster’s etcd key-value store. By default, Kubernetes Secrets are base64-encoded and are not automatically encrypted at the application object level unless encryption is configured. Amazon EKS provides a managed capability to encrypt Kubernetes Secrets at rest in etcd using AWS Key Management Service (KMS). The requirement explicitly states that “all secrets that are stored in Amazon EKS must be encrypted in the Kubernetes etcd key-value store,” which maps directly to enabling EKS secrets encryption with a customer-managed KMS key.

Option B is exactly this: create a KMS key and enable EKS KMS secrets encryption on the cluster. With this enabled, EKS uses envelope encryption so that Secrets are encrypted when stored in etcd, and decrypt operations are controlled through KMS permissions. This is the standard, AWS-native method that fulfills the requirement without requiring application changes or external secret stores for the encryption-at-rest requirement in etcd.

Option A (Secrets Manager) is a strong service for secret lifecycle management and rotation, but it does not by itself guarantee that Kubernetes Secrets stored in etcd are encrypted unless EKS secrets encryption is also enabled or the cluster avoids storing secrets in etcd entirely. The question specifically targets etcd encryption. Option C is unrelated: the EBS CSI driver concerns persistent volumes, not etcd secret encryption. Option D concerns EBS volume encryption and a specific AWS-managed key alias used for EBS; it also does not address etcd encryption for Kubernetes Secrets.

Therefore, B is the correct solution because it directly enables encryption of Kubernetes Secrets within etcd using KMS.

To access an EFS file system across accounts and VPCs, the EFS must be mounted using VPC peering or AWS Transit Gateway, and the EC2 instances must use the amazon-efs-utils package with the correct mount target or access point.

Using an EFS access point simplifies access management, especially across accounts, by providing a POSIX identity and access policy layer.

VPC sharing doesn’t support EFS directly unless the subnet and resources are shared properly, which requires redeployment. Therefore, option D is the most complete and correct.

TheAWS WAF Bot Control managed ruleis designed to automatically detect and mitigate bot traffic. This feature is particularly useful for addressing malicious traffic and conserving compute resources by filtering unnecessary requests at the ALB level.

Option A:Blocking IP addresses manually introduces significant operational overhead and is not scalable against dynamic, worldwide malicious traffic.

Option C:AWS Shield provides DDoS protection, but the scenario does not describe a DDoS attack. WAF is better suited for managing application-layer threats like bot traffic.

Option D:The AWS WAF IP reputation rule helps block traffic from known bad IPs but may not address bot traffic effectively.

AWS Documentation References:

AWS WAF Bot Control

AWS WAF Managed Rules