documentation_complete: true


title: 'Minimize user access to Amazon ECR'

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.

severity: unknown

identifiers:
  cce@eks: CCE-89643-1

references:
  cis@eks: 5.1.2

ocil_clause: 'access to the container image registry is restricted'

ocil: |-
  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.

  <b>Topics</b>

  <ol>
  <li>Amazon ECR Identity-Based Policies</li>
  <li>Amazon ECR Resource-Based Policies</li>
  <li>Authorization Based on Amazon ECR Tags</li>
  <li>Amazon ECR IAM Roles</li>
  </ol>

  <b>Amazon ECR Identity-Based Policies</b>

  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.

  <b>Actions</b>

  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: <tt>"Action": [ "ecr:action1", "ecr:action2"</tt> You can specify
  multiple actions using wildcards (<tt>*</tt>). For example, to specify all
  actions that begin with the word Describe, include the following action:
  <tt>"Action": "ecr:Describe*"</tt> To see a list of Amazon ECR actions, see
  Actions, Resources, and Condition Keys for Amazon Elastic Container
  Registry in the IAM User Guide.

  <b>Resources</b>

  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 (<tt>*</tt>) to
  indicate that the statement applies to all resources.

  An Amazon ECR repository resource has the following ARN:
  <tt>arn:$<i>{Partition}</i>:ecr:$<i>{Region}</i>:$<i>{Account}</i>:repository/$<i>{Repository-name}</i></tt>
  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:
  <tt>"Resource": "arn:aws:ecr:us-east-1:123456789012:repository/my-repo"</tt>
  To specify all repositories that belong to a specific account, use the
  wildcard (<tt>*</tt>): "Resource":
  <tt>"arn:aws:ecr:us-east-1:123456789012:repository/*"</tt>
  To specify multiple resources in a single statement, separate the ARNs with
  commas. <tt>"Resource": [ "resource1", "resource2"</tt>
  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.

  <b>Condition Keys</b>

  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.
