AWS S3 Access Point Essentials and Best Practices

AWS S3 Access Points provide a simplified way to access S3 resources, making it easier to manage access to your data.

An Access Point is a network endpoint that allows you to access your S3 resources without needing to know the bucket name or ARN.

To create an Access Point, you'll need to specify the S3 bucket and the IAM role or user that will be accessing the data.

Using an Access Point can help improve performance and simplify access to your data, reducing the need for complex bucket policies and IAM permissions.

Amazon S3 Access Points are a feature that allows customers to create a single virtual endpoint, or access point, to manage their data stored in Amazon S3.

You can define logical names that can be used to refer to your S3 buckets by creating an access point.

Creating an access point simplifies the creation of grants, which you can use to provide users with fine-grained access permissions to specific buckets or objects.

To create an access point, customers log into their Amazon S3 account and go to the “Access Point” tab in the left-hand navigation menu.

From there, they can easily click the “Create Access Point” button to define a custom access point policy.

Once created, customers can quickly provide users with fine-grained access permissions to specific buckets or objects by creating grants.

Access points also simplify traffic monitoring from a single location for additional security and visibility.

Configuring S3 Access Points is a crucial step in managing data access for your application. You need to give the permission to access your S3 access point in the IAM role.

To do this, you'll need to create two policies: one S3 bucket policy and one S3 Access Point policy. The S3 Access Point policy allows full S3 access to your access point, while the bucket policy defines which actions are allowed from a particular access point account or VPC.

The S3 access point syntax requires you to add "objects/" prefix in your resource specification. For example, to allow listing components inside an access-point folder, you need to specify "access-point/folder/objects/".

Here are some key actions you can allow in an access point policy:

Using S3 Access Points can simplify how you manage data access for your application set to your shared data sets on S3.

You no longer have to manage a single, complex bucket policy with hundreds of different permission rules that need to be written, read, tracked, and audited.

To restrict access to your S3 storage, you can limit all access to happen from a Virtual Private Cloud (VPC) using an S3 Access Point.

This can be especially useful if you're developing a multi-tenant application that needs to access data stored in Amazon S3, as it allows you to control access at the tenant level.

You can also limit access to specific account IDs by specifying VPC Endpoint policies that permit access only to access points (and thus buckets) owned by specific account IDs.

Having a unique name for your S3 Access Point can also be beneficial, as it allows you to specify any name that is unique within the account and region.

For example, you can now have a “test” access point in every account and region.

Here are some specific use cases where S3 Access Points can be particularly helpful:

By using S3 Access Points, you can create separate endpoints for applications or clients, each with access policies, permissions, and network configurations.

When configuring S3 Access Points, it's essential to understand how to grant access to specific users or roles. You can do this by creating an access point policy that defines the permissions and conditions for access.

An access point policy grant can be used to grant IAM users or roles access to specific objects or buckets through an access point. For example, you can grant an IAM user access to GET and PUT objects with a specific prefix through an access point.

To delegate access control from the bucket to the access point, you can add a statement to the underlying bucket policy. This allows the access point to inherit the permissions from the bucket.

You can also use an IAM role instead of a user to grant access to an access point. This is useful when you want to grant access to a service or application that uses an IAM role.

Here are some examples of access point policies that you can use to grant access to specific users or roles:

By using these access point policies, you can fine-grain control access to your S3 buckets and objects, and ensure that only authorized users or roles can access specific resources.

You can delegate access control for a bucket to the bucket's access points, allowing full access to all access points owned by the bucket owner's account.

To configure IAM policies for using access points, you need to control the use of the access point by resource, user, or other conditions. This ensures that both the access point and the underlying bucket permit the request.

You can use IAM resource policies to control access to the access point, and also define conditions like s3:DataAccessPointAccount, s3:DataAccessPointArn, and s3:AccessPointNetworkOrigin to match on the access point ARN, account ID, or network origin.

Here are the three new condition keys introduced by S3 access points that can be used in IAM policies to control access to your resources:

Configuring IAM policies is a crucial step in securing your Amazon S3 resources. To control access to your S3 Access Points, you can use IAM policies that allow or deny specific actions based on conditions such as the access point ARN, account ID, or network origin.

You can delegate access control from the bucket to the access point as described in Delegating access control to access points, or add the same permissions contained in the access point policy to the underlying bucket's policy. This ensures that the access point policy is only effective if the underlying bucket also allows the same access.

To create an IAM policy for an access point, you can use the following example as a starting point: "Example Access point policy grant". This policy grants IAM user Alice in account 123456789012 permissions to GET and PUT objects with the prefix Alice/ through access point my-access-point in account 123456789012.

The policy includes a condition key called `s3:DataAccessPointArn` which matches on the access point ARN. You can also use other condition keys such as `s3:DataAccessPointAccount` to match on the account ID of the owner of an access point, or `s3:AccessPointNetworkOrigin` to match on the network origin.

Here are some key condition keys to keep in mind when configuring IAM policies for S3 Access Points:

By using these condition keys, you can create IAM policies that control access to your S3 Access Points based on specific conditions.

Access point names must be unique within a single AWS account and Region.

To ensure this uniqueness, the name must comply with DNS naming restrictions. This means it can't contain certain characters like underscores, uppercase letters, or periods.

A good access point name should begin with a number or lowercase letter. This is a clear and concise way to start the name.

The name should be between 3 and 50 characters long. This length provides enough room for a descriptive name without being too long or cumbersome.

Here are the naming rules in a concise list: