Security

Correct Answer: Configure a security group associated with the EC2 instance to only allow necessary inbound traffic on specific ports

The best answer is to configure a security group associated with the EC2 instance to only allow necessary inbound traffic on specific ports. Security groups act as virtual firewalls at the instance level, controlling inbound and outbound traffic. By configuring the security group to allow only the required ports and protocols, you can effectively restrict unauthorized access to the EC2 instance. Modifying the network ACL to allow all inbound traffic on any port is not recommended as it would open the instance to potential security risks. Network ACLs operate at the subnet level and should be used as an additional layer of security, not as the primary means of controlling traffic. VPC flow logs are used for monitoring and troubleshooting network traffic, but they do not actively filter or control traffic based on IP addresses. They provide visibility into network traffic, but do not serve as a security measure. Assigning an Elastic IP address and creating a custom route table entry does not directly control inbound traffic to the EC2 instance. Elastic IP addresses are used for providing a static public IP address, while route tables are used for directing network traffic between subnets and the internet gateway. They do not provide granular control over inbound traffic at the instance level.

Correct Answer: Assign an IAM role to the EC2 instance with the necessary S3 permissions

Assigning an IAM role to the EC2 instance is the most secure way to grant the necessary S3 permissions. IAM roles provide temporary credentials and eliminate the need to store sensitive access keys within the application code or configuration files on the EC2 instance. This approach follows the principle of least privilege and ensures that the EC2 instance has only the specific permissions required to access the S3 bucket. Storing AWS access keys directly in the application code on the EC2 instance is insecure because if the instance is compromised, the access keys can be easily exposed. Enabling public access to the S3 bucket and relying solely on bucket policies for access control is not recommended, as it increases the risk of unauthorized access. Using S3 pre-signed URLs with an expiration time of 1 year is excessive and violates the principle of granting time-limited access. Pre-signed URLs should have a short expiration time to mitigate the risk of unauthorized access if the URLs are compromised.

Correct Answer: AWS Key Management Service (KMS)

Amazon RDS supports encryption at rest using AWS Key Management Service (KMS). It integrates with KMS to perform encryption and decryption operations, providing an encrypted storage volume for RDS instances.