IAM identifiers

IAM uses a few different identifiers for users, IAM groups, roles, policies, and server certificates. This section describes the identifiers and when you use each.

Friendly names and paths

When you create a user, a role, a user group, or a policy, or when you upload a server certificate, you give it a friendly name. Examples include Bob, TestApp1, Developers, ManageCredentialsPermissions, or ProdServerCert.

If you use the IAM API or AWS Command Line Interface (AWS CLI) to create IAM resources, you can add an optional path. You can use a single path, or nest multiple paths as a folder structure. For example, you could use the nested path /division_abc/subdivision_xyz/product_1234/engineering/ to match your company organizational structure. You could then create a policy to allow all users in that path to access the policy simulator API. To view this policy, see IAM: Access the policy simulator API based on user path. For information about how a friendly name can be specified, see the User API documentation. For additional examples of how you might use paths, see IAM ARNs.

When you use AWS CloudFormation to create resources, you can specify a path for users, IAM groups, and roles, and customer managed policies.

If you have a user and user group in the same path, IAM doesn't automatically put the user in that user group. For example, you might create a Developers user group and specify the path as /division_abc/subdivision_xyz/product_1234/engineering/. If you create a user named Bob and add the same path to him, this doesn't automatically put Bob in the Developers user group. IAM doesn't enforce any boundaries between users or IAM groups based on their paths. Users with different paths can use the same resources if they've been granted permission to those resources. The number and size of IAM resources in an AWS account are limited. For more information, see IAM and AWS STS quotas.

IAM ARNs

Most resources have a friendly name for example, a user named Bob or a user group named Developers. However, the permissions policy language requires you to specify the resource or resources using the following Amazon Resource Name (ARN) format.

arn:partition:service:region:account:resource

Where:

You can specify IAM and AWS STS ARNs using the following syntax. The Region portion of the ARN is blank because IAM resources are global.

Syntax:

arn:aws:iam::account:root  
arn:aws:iam::account:user/user-name-with-path
arn:aws:iam::account:group/group-name-with-path
arn:aws:iam::account:role/role-name-with-path
arn:aws:iam::account:policy/policy-name-with-path
arn:aws:iam::account:instance-profile/instance-profile-name-with-path
arn:aws:sts::account:federated-user/user-name
arn:aws:sts::account:assumed-role/role-name/role-session-name
arn:aws:sts::account:self
arn:aws:iam::account:mfa/virtual-device-name-with-path
arn:aws:iam::account:u2f/u2f-token-id
arn:aws:iam::account:server-certificate/certificate-name-with-path
arn:aws:iam::account:saml-provider/provider-name
arn:aws:iam::account:oidc-provider/provider-name

Many of the following examples include paths in the resource part of the ARN. Paths cannot be created or manipulated in the AWS Management Console. To use paths, you must work with the resource by using the AWS API, the AWS CLI, or the Tools for Windows PowerShell.

Examples:

arn:aws:iam::123456789012:root
arn:aws:iam::123456789012:user/JohnDoe
arn:aws:iam::123456789012:user/division_abc/subdivision_xyz/JaneDoe
arn:aws:iam::123456789012:group/Developers
arn:aws:iam::123456789012:group/division_abc/subdivision_xyz/product_A/Developers
arn:aws:iam::123456789012:role/S3Access
arn:aws:iam::123456789012:role/application_abc/component_xyz/RDSAccess
arn:aws:iam::123456789012:role/aws-service-role/access-analyzer.amazonaws.com/AWSServiceRoleForAccessAnalyzer
arn:aws:iam::123456789012:role/service-role/QuickSightAction
arn:aws:iam::123456789012:policy/UsersManageOwnCredentials
arn:aws:iam::123456789012:policy/division_abc/subdivision_xyz/UsersManageOwnCredentials
arn:aws:iam::123456789012:instance-profile/Webserver
arn:aws:sts::123456789012:federated-user/JohnDoe
arn:aws:sts::123456789012:assumed-role/Accounting-Role/JaneDoe
arn:aws:sts::123456789012:self
arn:aws:iam::123456789012:mfa/JaneDoeMFA
arn:aws:iam::123456789012:u2f/user/JohnDoe/default (U2F security key)
arn:aws:iam::123456789012:server-certificate/ProdServerCert
arn:aws:iam::123456789012:server-certificate/division_abc/subdivision_xyz/ProdServerCert
arn:aws:iam::123456789012:saml-provider/ADFSProvider
arn:aws:iam::123456789012:oidc-provider/GoogleProvider
arn:aws:iam::123456789012:oidc-provider/oidc.eks.us-west-2.amazonaws.com/id/a1b2c3d4567890abcdefEXAMPLE11111
arn:aws:iam::123456789012:oidc-provider/server.example.org

The following examples provide more detail to help you understand the ARN format for different types of IAM and AWS STS resources.

Another important ARN is the root user ARN. Although this is not an IAM resource, you should be familiar with the format of this ARN. It is often used in the Principal element of a resource-based policy.

The following example shows a policy you could assign to Richard to allow him to manage his access keys. Notice that the resource is the IAM user Richard.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "ManageRichardAccessKeys",
            "Effect": "Allow",
            "Action": [
                "iam:*AccessKey*",
                "iam:GetUser"
            ],
            "Resource": "arn:aws:iam::*:user/division_abc/subdivision_xyz/Richard"
        },
        {
            "Sid": "ListForConsole",
            "Effect": "Allow",
            "Action": "iam:ListUsers",
            "Resource": "*"
        }
    ]
}

Using wildcards and paths in ARNs

You can use wildcards in the resource portion of the ARN to specify multiple users or IAM groups or policies. For example, to specify all users working on product_1234, you use:

arn:aws:iam::123456789012:user/division_abc/subdivision_xyz/product_1234/*

If you have users whose names start with the string app_, you could refer to them all with the following ARN.

arn:aws:iam::123456789012:user/division_abc/subdivision_xyz/product_1234/app_*

To specify all users, IAM groups, or policies in your AWS account, use a wildcard after the user/, group/, or policy/ part of the ARN, respectively.

arn:aws:iam::123456789012:user/*
arn:aws:iam::123456789012:group/*
arn:aws:iam::123456789012:policy/*

If you specify the following ARN for a user arn:aws:iam::111122223333:user/* it matches both of the following examples.

arn:aws:iam::111122223333:user/JohnDoe
arn:aws:iam::111122223333:user/division_abc/subdivision_xyz/JaneDoe

But, if you specify the following ARN for a user arn:aws:iam::111122223333:user/division_abc* it matches the second example, but not the first.

arn:aws:iam::111122223333:user/JohnDoe
arn:aws:iam::111122223333:user/division_abc/subdivision_xyz/JaneDoe

Don't use a wildcard in the user/, group/, or policy/ part of the ARN. For example, IAM does not allow the following:

arn:aws:iam::123456789012:u*

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:*",
      "Resource": "arn:aws:s3:::example_bucket/marketing/newproductlaunch/widget/*"
    },
    {
      "Effect": "Allow",
      "Action": "s3:ListBucket*",
      "Resource": "arn:aws:s3:::example_bucket",
      "Condition": {"StringLike": {"s3:prefix": "marketing/newproductlaunch/widget/*"}}
    }
  ]
}

Unique identifiers

When IAM creates a user, user group, role, policy, instance profile, or server certificate, it assigns a unique ID to each resource. The unique ID looks like this:

AIDAJQABLZS4A3QDU576Q

For the most part, you use friendly names and ARNs when you work with IAM resources. That way you don't need to know the unique ID for a specific resource. However, the unique ID can sometimes be useful when it isn't practical to use friendly names.

One example reuses friendly names in your AWS account. Within your account, a friendly name for a user, user group, role, or policy must be unique. For example, you might create an IAM user named John. Your company uses Amazon S3 and has a bucket with folders for each employee. IAM user John is a member of an IAM user group named User-S3-Access with permissions that allows users access only to their own folders in the bucket. For an example of how you might create an identity-based policy that allows IAM users to access their own bucket object in S3 using the friendly name of users, see Amazon S3: Allows IAM users access to their S3 home directory, programmatically and in the console.

Suppose that the employee named John leaves your company and you delete the corresponding IAM user named John. But later another employee named John starts, and you create a new IAM user named John. You add the new IAM user named John to the existing IAM user group User-S3-Access. If the policy associated to the user group specifies the friendly IAM user name John, the policy allows the new John to access information that was left by the former John.

In general, we recommend that you specify the ARN for the resource in your policies instead of its unique ID. However, every IAM user has a unique ID, even if you create a new IAM user that reuses a friendly name you deleted before. In the example, the old IAM user John and the new IAM user John have different unique IDs. You can create resource-based policies that grant access by unique ID and not just by user name. Doing so reduces the chance that you could inadvertently grant access to information that an employee should not have.

The following example shows how you might specify unique IDs in the Principal element of a resource-based policy.

"Principal": {
  "AWS": [
    "arn:aws:iam::111122223333:role/role-name",
    "AIDACKCEVSQ6C2EXAMPLE",
    "AROADBQP57FF2AEXAMPLE"
  }

The following example shows how you might specify unique IDs in the Condition element of a policy using global condition key aws:userid.

"Condition": {
    "StringLike": {
      "aws:userId": [
        "AIDACKCEVSQ6C2EXAMPLE",
        "AROADBQP57FF2AEXAMPLE:role-session-name",
        "AROA1234567890EXAMPLE:*",
        "111122223333"
      ]
    }
  }

Another example where user IDs can be useful is if you maintain your own database (or other store) of IAM user or role information. The unique ID can provide a unique identifier for each IAM user or role you create. This is the case when you have IAM users or roles that reuse a name, as in the previous example.

Understanding unique ID prefixes

IAM uses the following prefixes to indicate what type of resource each unique ID applies to. Prefixes may vary based on when they were created.

Getting the unique identifier

The unique ID for an IAM resource is not available in the IAM console. To get the unique ID, you can use the following AWS CLI commands or IAM API calls.

AWS CLI:

IAM API: