Amazon Web Services DVA-C02 Exam With Confidence Using Practice Dumps

Problem: Directory access without file names fails.

S3 Static Website Hosting:

Configuring S3 as a static website enables automatic serving of index.html for directory requests.

Bucket policies ensure correct access permissions.

Updating the CloudFront origin simplifies routing.

Avoiding Public Exposure: The S3 website endpoint allows CloudFront to access content without making the bucket public.

Step 1: Understanding the Requirements

Best Practices for Security:

Minimize the use of hardcoded credentials or long-lived access keys.

Use IAM roles for EC2 instances to securely grant permissions to applications running on the instance.

Access Scope: The application needs read-only access to an S3 bucket.

Step 2: Solution Analysis

Option A:

Define an IAM policy with the required s3:GetObject permissions.

Attach this policy to an IAM role.

Assign the role to the EC2 instance profile.

This approach follows security best practices by eliminating the need for static credentials and using temporary, scoped credentials provided by the instance profile.

Correct option.

Option B:

IAM groups are used for organizing users, not for EC2 instances or instance profiles.

Not suitable.

Option C:

IAM users are associated with specific individuals or applications and require static credentials.

This violates security best practices for temporary credentials and roles.

Not suitable.

Option D:

IAM web identity federation is used for applications that authenticate users via third-party identity providers.

This is unnecessary for EC2 instances and does not align with the requirements.

Not suitable.

Step 3: Implementation Steps

Create an IAM Policy:

Grant read-only access to the S3 bucket:

json

Copy code

{

"Version": "2012-10-17",

"Statement": [

{

"Effect": "Allow",

"Action": "s3:GetObject",

"Resource": "arn:aws:s3:::your-bucket-name/*"

}

]

}

Attach the Policy to an IAM Role:

Create an IAM role and attach the policy to the role.

Associate the Role with the EC2 Instance:

Attach the role to the instance profile used by the EC2 instance.

AWS Developer References:

IAM Roles for Amazon EC2

Amazon S3 Permissions Reference

To prove integrity (and authenticity) of data in transit, the correct cryptographic primitive is a digital signature. AWS KMS supports signing and verification operations using asymmetric KMS keys designed for signing (for example, RSA_SIGN_PSS, RSA_SIGN_PKCS1, or ECC_NIST_P256 key specs). The developer signs the data (or more commonly, a hash of the data) using the private key, and the external recipient verifies the signature using the corresponding public key. If the data is modified in transit, signature verification fails, proving the content was changed.

Option C exactly describes this model: sign with the private key, share the public key. The private key remains protected (ideally never leaving KMS). The public key can be distributed safely because it cannot be used to forge signatures.

Option A (encryption) provides confidentiality, not integrity proof to a third party, and sharing a symmetric encryption key is insecure and breaks key management principles.

Option B is incorrect because symmetric keys do not provide non-repudiation and generally require the verifier to possess the same secret key, which would allow the verifier to forge signatures too. While HMAC can validate integrity between trusted parties, it does not meet the typical “prove integrity” requirement to an external party without sharing a secret.

Option D is backward and insecure: you never share a private key.

Therefore, use an asymmetric KMS signing key to sign with the private key and provide the public key for verification.