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5.1.2 Minimize user access to Amazon ECR (Manual)​

Profile Applicability​

• Level 1

Description​

Restrict user access to Amazon ECR, limiting interaction with build images to only authorized personnel and service accounts.

Rationale​

Weak access control to Amazon ECR may allow malicious users to replace built images with vulnerable containers.

Impact​

Care should be taken not to remove access to Amazon ECR for accounts that require this for their operation.

Audit​

Remediation​

Before you use IAM to manage access to Amazon ECR, you should understand what IAM features are available to use with Amazon ECR. To get a high-level view of how Amazon ECR and other AWS services work with IAM, see AWS Services That Work with IAM in the IAM User Guide.

Topics

  • Amazon ECR Identity-Based Policies
  • Amazon ECR Resource-Based Policies
  • Authorization Based on Amazon ECR Tags
  • Amazon ECR IAM Roles

Amazon ECR Identity-Based Policies

With IAM identity-based policies, you can specify allowed or denied actions and resources as well as the conditions under which actions are allowed or denied. Amazon ECR supports specific actions, resources, and condition keys. To learn about all of the elements that you use in a JSON policy, see IAM JSON Policy Elements Reference in the IAM User Guide.

Actions The Action element of an IAM identity-based policy describes the specific action or actions that will be allowed or denied by the policy. Policy actions usually have the same name as the associated AWS API operation. The action is used in a policy to grant permissions to perform the associated operation.

Policy actions in Amazon ECR use the following prefix before the action: ecr:. For example, to grant someone permission to create an Amazon ECR repository with the Amazon ECR CreateRepository API operation, you include the ecr:CreateRepository action in their policy. Policy statements must include either an Action or NotAction element. Amazon ECR defines its own set of actions that describe tasks that you can perform with this service.

To specify multiple actions in a single statement, separate them with commas as follows:

`"Action": [
 "ecr:action1",
 "ecr:action2"

You can specify multiple actions using wildcards (*). For example, to specify all actions that begin with the word Describe, include the following action:

"Action": "ecr:Describe*"

To see a list of Amazon ECR actions, see Actions, Resources, and Condition Keys for Amazon Elastic Container Registry in the IAM User Guide.

Resources The Resource element specifies the object or objects to which the action applies. Statements must include either a Resource or a NotResource element. You specify a resource using an ARN or using the wildcard (*) to indicate that the statement applies to all resources.

An Amazon ECR repository resource has the following ARN:

arn:${Partition}:ecr:${Region}:${Account}:repository/${Repository-name}

For more information about the format of ARNs, see Amazon Resource Names (ARNs) and AWS Service Namespaces.

For example, to specify the my-repo repository in the us-east-1 Region in your statement, use the following ARN:

"Resource": "arn:aws:ecr:us-east-1:123456789012:repository/my-repo"

To specify all repositories that belong to a specific account, use the wildcard (*):

"Resource": "arn:aws:ecr:us-east-1:123456789012:repository/*"

To specify multiple resources in a single statement, separate the ARNs with commas.

"Resource": [
 "resource1",
 "resource2"

To see a list of Amazon ECR resource types and their ARNs, see Resources Defined by Amazon Elastic Container Registry in the IAM User Guide. To learn with which actions you can specify the ARN of each resource, see Actions Defined by Amazon Elastic Container Registry.

Condition Keys The Condition element (or Condition block) lets you specify conditions in which a statement is in effect. The Condition element is optional. You can build conditional expressions that use condition operators, such as equals or less than, to match the condition in the policy with values in the request.

If you specify multiple Condition elements in a statement, or multiple keys in a single Condition element, AWS evaluates them using a logical AND operation. If you specify multiple values for a single condition key, AWS evaluates the condition using a logical OR operation. All of the conditions must be met before the statement's permissions are granted.

You can also use placeholder variables when you specify conditions. For example, you can grant an IAM user permission to access a resource only if it is tagged with their IAM user name. For more information, see IAM Policy Elements: Variables and Tags in the IAM User Guide.

Amazon ECR defines its own set of condition keys and also supports using some global condition keys. To see all AWS global condition keys, see AWS Global Condition Context Keys in the IAM User Guide.

Most Amazon ECR actions support the aws:ResourceTag and ecr:ResourceTag condition keys. For more information, see Using Tag-Based Access Control.

To see a list of Amazon ECR condition keys, see Condition Keys Defined by Amazon Elastic Container Registry in the IAM User Guide. To learn with which actions and resources you can use a condition key, see Actions Defined by Amazon Elastic Container Registry.

References​

https://docs.aws.amazon.com/AmazonECR/latest/userguide/image-scanning.html#scanning-repository