Securing Access to AWS S3 Bucket via VPC Endpoint

Answer: D.

Options A is incorrect because using Security Groups will not help to allow specific access to the S3 bucket via the VPC endpoint.

Options B is incorrect because using the route tables will not help to allow specific access to the S3 bucket via the VPC endpoint.

Option C is incorrect because it is the bucket policy that needs to be changed and not the IAM policy for restricting S3 buckets access only via a VPC endpoint.

Option D is CORRECT you can use Amazon S3 bucket policies to control access to buckets from specific Amazon Virtual Private Cloud (Amazon VPC) endpoints, or specific VPCs.

The bucket policy denies all access to the bucket if the specified endpoint is not being used.

Example bucket policy provided below, just make sure to replace the VPC endpoint ID with an appropriate value for your use case and disable console access to the specified bucket, because console requests don't originate from the specified VPC endpoint.

{

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

"Id": "Policy1415115909152",

"Statement": [

{

"Sid": "Access-to-specific-VPCE-only",

"Principal": "*",

"Action": "s3:*",

"Effect": "Deny",

"Resource": ["arn:aws:s3:::awsexamplebucket1",

"arn:aws:s3:::awsexamplebucket1/*"],

"Condition": {

"StringNotEquals": {

"aws:SourceVpce": "vpce-1a2b3c4d"

}

}

}

]

}

For more information on example bucket policies for VPC endpoints, kindly refer to the following URL:

https://docs.aws.amazon.com/AmazonS3/latest/dev/example-bucket-policies-vpc-endpoint.html

The correct answer to this question is D. Modify the S3 bucket policy to only allow access from the S3 VPC endpoint.

Explanation:

An Amazon VPC (Virtual Private Cloud) is a logically isolated section of the Amazon Web Services (AWS) Cloud where you can launch AWS resources in a defined virtual network. Amazon S3 (Simple Storage Service) is an object storage service that offers industry-leading scalability, data availability, security, and performance. In order to ensure that the bucket can only be accessed by the VPC endpoint, you need to configure the S3 bucket policy to allow access only from the VPC endpoint.

Option A, modifying the security groups for the VPC to allow access to the S3 bucket, is not the correct answer because security groups are used to control inbound and outbound traffic to Amazon EC2 instances, not to S3 buckets.

Option B, modifying the route tables to allow access from the VPC endpoint, is not the correct answer because route tables are used to determine where network traffic is directed within a VPC, not to control access to S3 buckets.

Option C, modifying the IAM policy of the bucket to only allow access from the S3 VPC endpoint, is not the correct answer because IAM (Identity and Access Management) policies are used to manage access to AWS resources, not to control access to S3 buckets.

Therefore, the correct answer is D, modifying the S3 bucket policy to only allow access from the S3 VPC endpoint. This can be achieved by creating a bucket policy that explicitly denies access to anyone who is not coming from the VPC endpoint. Here's an example of such a bucket policy:

jsonCopy code
{     "Version": "2012-10-17",     "Statement": [         {             "Sid": "AllowVPCEndpointOnly",             "Effect": "Deny",             "NotPrincipal": {                 "AWS": "*"             },             "Action": "s3:*",             "Resource": [                 "arn:aws:s3:::example-bucket",                 "arn:aws:s3:::example-bucket/*"             ],             "Condition": {                 "StringNotEquals": {                     "aws:SourceVpce": "vpce-1234567890"                 }             }         }     ] } 

In this policy, the "Effect" is set to "Deny", which means that all requests will be denied by default, unless they meet the specific criteria defined in the policy. The "NotPrincipal" is set to "" to deny access to all principals (i.e., all AWS accounts and IAM users and roles). The "Action" is set to "s3:" to deny all S3 actions. The "Resource" is set to the Amazon Resource Name (ARN) of the S3 bucket and all objects within it. Finally, the "Condition" is set to "aws:SourceVpce", which specifies that the request must come from the specified VPC endpoint (in this case, "vpce-1234567890") in order to be allowed.

By creating a bucket policy like this, you can ensure that only requests coming from the specified VPC endpoint will be allowed to access the S3 bucket.