Troubleshooting AWS EC2 Instance Access to S3 Bucket: Resolving 403 Error

Resolving 403 Error when Accessing S3 Bucket from EC2 Instance

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Question

A company has set up an application on an EC2 Instance in a private subnet.

This Instance is used to process videos.

The Instance has been enabled with Enhanced Networking.

The Instance now needs to get videos from an S3 bucket for processing.

When the EC2 Instance tries to access the S3 bucket, a 403 error is returned.

What needs to be done to ensure that the error gets resolved?

Answers

Explanations

Click on the arrows to vote for the correct answer

A. B. C. D.

Answer - A.

The object owner must assign an IAM Role to the particular Instance to access S3.

Option B is incorrect since the VPC endpoint needs to be attached to the subnet ( the subnet in which the EC2 instances are placed ).

Options C and D are incorrect since adding the CIDR range will not help.

For more information on VPC gateways, please refer to the below URLs.

https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpce-gateway.html https://docs.aws.amazon.com/AmazonS3/latest/dev/s3-dg.pdf

The 403 error returned when the EC2 Instance tries to access the S3 bucket indicates that there is a permission issue. To resolve this issue, one or more of the following solutions can be applied:

A. Assign an IAM Role to the Instance: This option involves creating an IAM role with appropriate permissions for accessing the S3 bucket and then assigning the IAM role to the EC2 instance. The IAM role should have permissions to access the S3 bucket, and the EC2 instance should have permission to assume the role.

B. Create and attach a VPC endpoint to the EC2 Instance: This option involves creating a VPC endpoint for S3 in the VPC where the EC2 instance resides and then attaching the endpoint to the EC2 instance's subnet. This will allow the EC2 instance to access the S3 bucket over a private network connection without the need for a public internet connection.

C. Add the CIDR range for the S3 bucket to the Security Groups for the EC2 Instance: This option involves adding the CIDR range for the S3 bucket to the Security Groups for the EC2 Instance. This will allow traffic from the EC2 instance to the S3 bucket.

D. Add the CIDR range for the S3 bucket to the NACLs for the subnet: This option involves adding the CIDR range for the S3 bucket to the NACLs for the subnet where the EC2 instance resides. This will allow traffic from the EC2 instance to the S3 bucket.

Out of these options, option B is the most secure because it allows access to S3 only over a private network connection. However, the choice of the solution depends on the specific requirements of the use case.