How AWS CloudTrail works with IAM

Before you use IAM to manage access to CloudTrail, learn what IAM features are available to use with CloudTrail.

To get a high-level view of how CloudTrail and other AWS services work with most IAM features, see AWS services that work with IAM in the IAM User Guide.

Identity-based policies for CloudTrail

Supports identity-based policies: Yes

Identity-based policies are JSON permissions policy documents that you can attach to an identity, such as an IAM user, group of users, or role. These policies control what actions users and roles can perform, on which resources, and under what conditions. To learn how to create an identity-based policy, see Define custom IAM permissions with customer managed policies in the IAM User Guide.

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. You can't specify the principal in an identity-based policy because it applies to the user or role to which it is attached. To learn about all of the elements that you can use in a JSON policy, see IAM JSON policy elements reference in the IAM User Guide.

Identity-based policy examples for CloudTrail

To view examples of CloudTrail identity-based policies, see Identity-based policy examples for AWS CloudTrail.

Resource-based policies within CloudTrail

Supports resource-based policies: Partial

Resource-based policies are JSON policy documents that you attach to a resource. Examples of resource-based policies are IAM role trust policies and Amazon S3 bucket policies. In services that support resource-based policies, service administrators can use them to control access to a specific resource. For the resource where the policy is attached, the policy defines what actions a specified principal can perform on that resource and under what conditions. You must specify a principal in a resource-based policy. Principals can include accounts, users, roles, federated users, or AWS services.

To enable cross-account access, you can specify an entire account or IAM entities in another account as the principal in a resource-based policy. Adding a cross-account principal to a resource-based policy is only half of establishing the trust relationship. When the principal and the resource are in different AWS accounts, an IAM administrator in the trusted account must also grant the principal entity (user or role) permission to access the resource. They grant permission by attaching an identity-based policy to the entity. However, if a resource-based policy grants access to a principal in the same account, no additional identity-based policy is required. For more information, see Cross account resource access in IAM in the IAM User Guide.

CloudTrail supports the following types of resource-based policies:

Examples

To view examples of CloudTrail resource-based policies, see AWS CloudTrail resource-based policy examples.

Policy actions for CloudTrail

Supports policy actions: Yes

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

The Action element of a JSON policy describes the actions that you can use to allow or deny access in a policy. Policy actions usually have the same name as the associated AWS API operation. There are some exceptions, such as permission-only actions that don't have a matching API operation. There are also some operations that require multiple actions in a policy. These additional actions are called dependent actions.

Include actions in a policy to grant permissions to perform the associated operation.

To see a list of CloudTrail actions, see Actions Defined by AWS CloudTrail in the Service Authorization Reference.

Policy actions in CloudTrail use the following prefix before the action:

cloudtrail

For example, to grant someone permission to list tags for a trail with the ListTags API operation, you include the cloudtrail:ListTags action in their policy. Policy statements must include either an Action or NotAction element. CloudTrail 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": [
      "cloudtrail:AddTags",
      "cloudtrail:ListTags",
      "cloudtrail:RemoveTags

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

"Action": "cloudtrail:Get*"

Policy resources for CloudTrail

Supports policy resources: Yes

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

The Resource JSON policy element specifies the object or objects to which the action applies. Statements must include either a Resource or a NotResource element. As a best practice, specify a resource using its Amazon Resource Name (ARN). You can do this for actions that support a specific resource type, known as resource-level permissions.

For actions that don't support resource-level permissions, such as listing operations, use a wildcard (*) to indicate that the statement applies to all resources.

"Resource": "*"

To see a list of CloudTrail resource types and their ARNs, see Resources Defined by AWS CloudTrail in the Service Authorization Reference. To learn with which actions you can specify the ARN of each resource, see Actions Defined by AWS CloudTrail.

In CloudTrail, there are four resource types: trails, event data stores, dashboards, and channels. Each resource has a unique Amazon Resource Name (ARN) associated with it. In a policy, you use an ARN to identify the resource that the policy applies to. CloudTrail does not currently support other resource types, which are sometimes referred to as subresources.

The CloudTrail trail resource has the following ARN:

arn:${Partition}:cloudtrail:${Region}:${Account}:trail/{TrailName}

The CloudTrail event data store resource has the following ARN:

arn:${Partition}:cloudtrail:${Region}:${Account}:eventdatastore/{EventDataStoreId}

The CloudTrail dashboard resource has the following ARN:

arn:${Partition}:cloudtrail:${Region}:${Account}:dashboard/{DashboardName}

The CloudTrail channel resource has the following ARN:

arn:${Partition}:cloudtrail:${Region}:${Account}:channel/{ChannelId}

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

For example, for an AWS account with the ID 123456789012, to specify a trail named My-Trail that exists in the US East (Ohio) Region in your statement, use the following ARN:

"Resource": "arn:aws:cloudtrail:us-east-2:123456789012:trail/My-Trail"

To specify all trails that belong to a specific account in that AWS Region, use the wildcard (*):

"Resource": "arn:aws:cloudtrail:us-east-2:123456789012:trail/*"

Some CloudTrail actions, such as those for creating resources, can't be performed on a specific resource. In those cases, you must use the wildcard (*).

"Resource": "*"

Many CloudTrail API actions involve multiple resources. For example, CreateTrail requires an Amazon S3 bucket for storing log files, so a user must have permissions to write to the bucket. To specify multiple resources in a single statement, separate the ARNs with commas.

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

Policy condition keys for CloudTrail

Supports service-specific policy condition keys: No

Administrators can use AWS JSON policies to specify who has access to what. That is, which principal can perform actions on what resources, and under what conditions.

The Condition element (or Condition block) lets you specify conditions in which a statement is in effect. The Condition element is optional. You can create 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.

AWS supports global condition keys and service-specific condition keys. To see all AWS global condition keys, see AWS global condition context keys in the IAM User Guide.

CloudTrail doesn't define its own condition keys, but it supports using some global condition keys. To see all AWS global condition keys, see AWS Global Condition Context Keys in the IAM User Guide.

To see a list of CloudTrail condition keys, see Condition Keys for AWS CloudTrail in the Service Authorization Reference. To learn with which actions and resources you can use a condition key, see Actions Defined by AWS CloudTrail.

ACLs in CloudTrail

Supports ACLs: No

Access control lists (ACLs) control which principals (account members, users, or roles) have permissions to access a resource. ACLs are similar to resource-based policies, although they do not use the JSON policy document format.

ABAC with CloudTrail

Supports ABAC (tags in policies): Yes

Attribute-based access control (ABAC) is an authorization strategy that defines permissions based on attributes. In AWS, these attributes are called tags. You can attach tags to IAM entities (users or roles) and to many AWS resources. Tagging entities and resources is the first step of ABAC. Then you design ABAC policies to allow operations when the principal's tag matches the tag on the resource that they are trying to access.

ABAC is helpful in environments that are growing rapidly and helps with situations where policy management becomes cumbersome.

To control access based on tags, you provide tag information in the condition element of a policy using the aws:ResourceTag/key-name, aws:RequestTag/key-name, or aws:TagKeys condition keys.

If a service supports all three condition keys for every resource type, then the value is Yes for the service. If a service supports all three condition keys for only some resource types, then the value is Partial.

For more information about ABAC, see Define permissions with ABAC authorization in the IAM User Guide. To view a tutorial with steps for setting up ABAC, see Use attribute-based access control (ABAC) in the IAM User Guide.

You can attach tags to CloudTrail resources or pass tags in a request to CloudTrail. For more information about tagging CloudTrail resources, see Creating a trail with the CloudTrail console and Creating, updating, and managing trails with the AWS CLI.

Using temporary credentials with CloudTrail

Supports temporary credentials: Yes

Some AWS services don't work when you sign in using temporary credentials. For additional information, including which AWS services work with temporary credentials, see AWS services that work with IAM in the IAM User Guide.

You are using temporary credentials if you sign in to the AWS Management Console using any method except a user name and password. For example, when you access AWS using your company's single sign-on (SSO) link, that process automatically creates temporary credentials. You also automatically create temporary credentials when you sign in to the console as a user and then switch roles. For more information about switching roles, see Switch from a user to an IAM role (console) in the IAM User Guide.

You can manually create temporary credentials using the AWS CLI or AWS API. You can then use those temporary credentials to access AWS. AWS recommends that you dynamically generate temporary credentials instead of using long-term access keys. For more information, see Temporary security credentials in IAM.

Forward access sessions for CloudTrail

Supports forward access sessions (FAS): Yes

When you use an IAM user or role to perform actions in AWS, you are considered a principal. When you use some services, you might perform an action that then initiates another action in a different service. FAS uses the permissions of the principal calling an AWS service, combined with the requesting AWS service to make requests to downstream services. FAS requests are only made when a service receives a request that requires interactions with other AWS services or resources to complete. In this case, you must have permissions to perform both actions. For policy details when making FAS requests, see Forward access sessions.

Service roles for CloudTrail

Supports service roles: Yes

A service role is an IAM role that a service assumes to perform actions on your behalf. An IAM administrator can create, modify, and delete a service role from within IAM. For more information, see Create a role to delegate permissions to an AWS service in the IAM User Guide.

Service-linked roles for CloudTrail

Supports service-linked roles: Yes

A service-linked role is a type of service role that is linked to an AWS service. The service can assume the role to perform an action on your behalf. Service-linked roles appear in your AWS account and are owned by the service. An IAM administrator can view, but not edit the permissions for service-linked roles.

CloudTrail supports a service-linked role for integration with AWS Organizations. This role is required for the creation of an organization trail or event data store. Organization trails and event data stores log events for all AWS accounts in an organization. For more information about creating or managing CloudTrail service-linked roles, see Using service-linked roles for AWS CloudTrail.