# Identity and Access Management for Amazon DynamoDB AWS Identity and Access Management (IAM) is an AWS service that helps an administrator securely control access to AWS resources. IAM administrators control who can be *authenticated* (signed in) and *authorized* (have permissions) to use DynamoDB resources. IAM is an AWS service that you can use with no additional charge. **Topics** + [Audience](#security_iam_audience) + [Authenticating with identities](#security_iam_authentication) + [Managing access using policies](#security_iam_access-manage) + [How Amazon DynamoDB works with IAM](security_iam_service-with-iam.md) + [Identity-based policy examples for Amazon DynamoDB](security_iam_id-based-policy-examples.md) + [Troubleshooting Amazon DynamoDB identity and access](security_iam_troubleshoot.md) + [IAM policy to prevent the purchase of DynamoDB reserved capacity](iam-policy-prevent-purchase-reserved-capacity.md) ## Audience How you use AWS Identity and Access Management (IAM) differs based on your role: + **Service user** - request permissions from your administrator if you cannot access features (see [Troubleshooting Amazon DynamoDB identity and access](security_iam_troubleshoot.md)) + **Service administrator** - determine user access and submit permission requests (see [How Amazon DynamoDB works with IAM](security_iam_service-with-iam.md)) + **IAM administrator** - write policies to manage access (see [Identity-based policy examples for Amazon DynamoDB](security_iam_id-based-policy-examples.md)) ## Authenticating with identities Authentication is how you sign in to AWS using your identity credentials. You must be authenticated as the AWS account root user, an IAM user, or by assuming an IAM role. You can sign in as a federated identity using credentials from an identity source like AWS IAM Identity Center (IAM Identity Center), single sign-on authentication, or Google/Facebook credentials. For more information about signing in, see [How to sign in to your AWS account](https://docs.aws.amazon.com/signin/latest/userguide/how-to-sign-in.html) in the *AWS Sign-In User Guide*. For programmatic access, AWS provides an SDK and CLI to cryptographically sign requests. For more information, see [AWS Signature Version 4 for API requests](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_sigv.html) in the *IAM User Guide*. ### AWS account root user When you create an AWS account, you begin with one sign-in identity called the AWS account *root user* that has complete access to all AWS services and resources. We strongly recommend that you don't use the root user for everyday tasks. For tasks that require root user credentials, see [Tasks that require root user credentials](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_root-user.html#root-user-tasks) in the *IAM User Guide*. ### Federated identity As a best practice, require human users to use federation with an identity provider to access AWS services using temporary credentials. A *federated identity* is a user from your enterprise directory, web identity provider, or Directory Service that accesses AWS services using credentials from an identity source. Federated identities assume roles that provide temporary credentials. For centralized access management, we recommend AWS IAM Identity Center. For more information, see [What is IAM Identity Center?](https://docs.aws.amazon.com/singlesignon/latest/userguide/what-is.html) in the *AWS IAM Identity Center User Guide*. ### IAM users and groups An *[IAM user](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_users.html)* is an identity with specific permissions for a single person or application. We recommend using temporary credentials instead of IAM users with long-term credentials. For more information, see [Require human users to use federation with an identity provider to access AWS using temporary credentials](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#bp-users-federation-idp) in the *IAM User Guide*. An [https://docs.aws.amazon.com/IAM/latest/UserGuide/id_groups.html](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_groups.html) specifies a collection of IAM users and makes permissions easier to manage for large sets of users. For more information, see [Use cases for IAM users](https://docs.aws.amazon.com/IAM/latest/UserGuide/gs-identities-iam-users.html) in the *IAM User Guide*. ### IAM roles An *[IAM role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html)* is an identity with specific permissions that provides temporary credentials. You can assume a role by [switching from a user to an IAM role (console)](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_use_switch-role-console.html) or by calling an AWS CLI or AWS API operation. For more information, see [Methods to assume a role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_manage-assume.html) in the *IAM User Guide*. IAM roles are useful for federated user access, temporary IAM user permissions, cross-account access, cross-service access, and applications running on Amazon EC2. For more information, see [Cross account resource access in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies-cross-account-resource-access.html) in the *IAM User Guide*. ## Managing access using policies You control access in AWS by creating policies and attaching them to AWS identities or resources. A policy defines permissions when associated with an identity or resource. AWS evaluates these policies when a principal makes a request. Most policies are stored in AWS as JSON documents. For more information about JSON policy documents, see [Overview of JSON policies](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies.html#access_policies-json) in the *IAM User Guide*. Using policies, administrators specify who has access to what by defining which **principal** can perform **actions** on what **resources**, and under what **conditions**. By default, users and roles have no permissions. An IAM administrator creates IAM policies and adds them to roles, which users can then assume. IAM policies define permissions regardless of the method used to perform the operation. ### Identity-based policies Identity-based policies are JSON permissions policy documents that you attach to an identity (user, group, or role). These policies control what actions identities 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](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_create.html) in the *IAM User Guide*. Identity-based policies can be *inline policies* (embedded directly into a single identity) or *managed policies* (standalone policies attached to multiple identities). To learn how to choose between managed and inline policies, see [Choose between managed policies and inline policies](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies-choosing-managed-or-inline.html) in the *IAM User Guide*. ### Resource-based policies Resource-based policies are JSON policy documents that you attach to a resource. Examples include 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. You must [specify a principal](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_principal.html) in a resource-based policy. Resource-based policies are inline policies that are located in that service. You can't use AWS managed policies from IAM in a resource-based policy. ### Other policy types AWS supports additional policy types that can set the maximum permissions granted by more common policy types: + **Permissions boundaries** – Set the maximum permissions that an identity-based policy can grant to an IAM entity. For more information, see [Permissions boundaries for IAM entities](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_boundaries.html) in the *IAM User Guide*. + **Service control policies (SCPs)** – Specify the maximum permissions for an organization or organizational unit in AWS Organizations. For more information, see [Service control policies](https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_scps.html) in the *AWS Organizations User Guide*. + **Resource control policies (RCPs)** – Set the maximum available permissions for resources in your accounts. For more information, see [Resource control policies (RCPs)](https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_rcps.html) in the *AWS Organizations User Guide*. + **Session policies** – Advanced policies passed as a parameter when creating a temporary session for a role or federated user. For more information, see [Session policies](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies.html#policies_session) in the *IAM User Guide*. ### Multiple policy types When multiple types of policies apply to a request, the resulting permissions are more complicated to understand. To learn how AWS determines whether to allow a request when multiple policy types are involved, see [Policy evaluation logic](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_evaluation-logic.html) in the *IAM User Guide*. # How Amazon DynamoDB works with IAM Before you use IAM to manage access to DynamoDB, learn what IAM features are available to use with DynamoDB. | IAM feature | DynamoDB support | | --- | --- | | [Identity-based policies](#security_iam_service-with-iam-id-based-policies) | Yes | | [Resource-based policies](#security_iam_service-with-iam-resource-based-policies) | Yes | | [Policy actions](#security_iam_service-with-iam-id-based-policies-actions) | Yes | | [Policy resources](#security_iam_service-with-iam-id-based-policies-resources) | Yes | | [Policy condition keys](#security_iam_service-with-iam-id-based-policies-conditionkeys) | Yes | | [ACLs](#security_iam_service-with-iam-acls) | No | | [ABAC (tags in policies)](#security_iam_service-with-iam-tags) | Yes | | [Temporary credentials](#security_iam_service-with-iam-roles-tempcreds) | Yes | | [Principal permissions](#security_iam_service-with-iam-principal-permissions) | Yes | | [Service roles](#security_iam_service-with-iam-roles-service) | Yes | | [Service-linked roles](#security_iam_service-with-iam-roles-service-linked) | Yes | To get a high-level view of how DynamoDB and other AWS services work with most IAM features, see [AWS services that work with IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html) in the *IAM User Guide*. ## Identity-based policies for DynamoDB **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](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_create.html) 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. To learn about all of the elements that you can use in a JSON policy, see [IAM JSON policy elements reference](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html) in the *IAM User Guide*. ### Identity-based policy examples for DynamoDB To view examples of DynamoDB identity-based policies, see [Identity-based policy examples for Amazon DynamoDB](security_iam_id-based-policy-examples.md). ## Resource-based policies within DynamoDB **Supports resource-based policies:** Yes 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](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_principal.html) 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. For more information, see [Cross account resource access in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies-cross-account-resource-access.html) in the *IAM User Guide*. ## Policy actions for DynamoDB **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. Include actions in a policy to grant permissions to perform the associated operation. To see a list of DynamoDB actions, see [Actions defined by Amazon DynamoDB](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazondynamodb.html#amazondynamodb-actions-as-permissions) in the *Service Authorization Reference*. Policy actions in DynamoDB use the following prefix before the action: ``` aws ``` To specify multiple actions in a single statement, separate them with commas. ``` "Action": [ "aws:action1", "aws:action2" ] ``` To view examples of DynamoDB identity-based policies, see [Identity-based policy examples for Amazon DynamoDB](security_iam_id-based-policy-examples.md). ## Policy resources for DynamoDB **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. As a best practice, specify a resource using its [Amazon Resource Name (ARN)](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference-arns.html). For actions that don't support resource-level permissions, use a wildcard (\$1) to indicate that the statement applies to all resources. ``` "Resource": "*" ``` To see a list of DynamoDB resource types and their ARNs, see [Resources defined by Amazon DynamoDB](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazondynamodb.html#amazondynamodb-resources-for-iam-policies) in the *Service Authorization Reference*. To learn with which actions you can specify the ARN of each resource, see [Actions defined by Amazon DynamoDB](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazondynamodb.html#amazondynamodb-actions-as-permissions). To view examples of DynamoDB identity-based policies, see [Identity-based policy examples for Amazon DynamoDB](security_iam_id-based-policy-examples.md). ## Policy condition keys for DynamoDB **Supports service-specific policy condition keys:** 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 `Condition` element specifies when statements execute based on defined criteria. You can create conditional expressions that use [condition operators](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition_operators.html), such as equals or less than, to match the condition in the policy with values in the request. To see all AWS global condition keys, see [AWS global condition context keys](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_condition-keys.html) in the *IAM User Guide*. To see a list of DynamoDB condition keys, see [Condition keys for Amazon DynamoDB](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazondynamodb.html#amazondynamodb-policy-keys) in the *Service Authorization Reference*. To learn with which actions and resources you can use a condition key, see [Actions defined by Amazon DynamoDB](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazondynamodb.html#amazondynamodb-actions-as-permissions). To view examples of DynamoDB identity-based policies, see [Identity-based policy examples for Amazon DynamoDB](security_iam_id-based-policy-examples.md). ## Access control lists (ACLs) in DynamoDB **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. ## Attribute-based access control (ABAC) with DynamoDB **Supports ABAC (tags in policies):** Yes Attribute-based access control (ABAC) is an authorization strategy that defines permissions based on attributes called tags. You can attach tags to IAM entities and AWS resources, then design ABAC policies to allow operations when the principal's tag matches the tag on the resource. To control access based on tags, you provide tag information in the [condition element](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html) 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](https://docs.aws.amazon.com/IAM/latest/UserGuide/introduction_attribute-based-access-control.html) in the *IAM User Guide*. To view a tutorial with steps for setting up ABAC, see [Use attribute-based access control (ABAC)](https://docs.aws.amazon.com/IAM/latest/UserGuide/tutorial_attribute-based-access-control.html) in the *IAM User Guide*. ## Using Temporary credentials with DynamoDB **Supports temporary credentials:** Yes Temporary credentials provide short-term access to AWS resources and are automatically created when you use federation or switch roles. AWS recommends that you dynamically generate temporary credentials instead of using long-term access keys. For more information, see [Temporary security credentials in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_temp.html) and [AWS services that work with IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html) in the *IAM User Guide*. ## Cross-service principal permissions for DynamoDB **Supports forward access sessions (FAS):** Yes Forward access sessions (FAS) use the permissions of the principal calling an AWS service, combined with the requesting AWS service to make requests to downstream services. For policy details when making FAS requests, see [Forward access sessions](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_forward_access_sessions.html). ## Service roles for DynamoDB **Supports service roles:** Yes A service role is an [IAM role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html) 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](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_for-service.html) in the *IAM User Guide*. **Warning** Changing the permissions for a service role might break DynamoDB functionality. Edit service roles only when DynamoDB provides guidance to do so. ## Service-linked roles for DynamoDB **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. For details about creating or managing service-linked roles, see [AWS services that work with IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_aws-services-that-work-with-iam.html). Find a service in the table that includes a `Yes` in the **Service-linked role** column. Choose the **Yes** link to view the service-linked role documentation for that service. ### Supported service-linked roles in DynamoDB The following service-linked roles are supported in DynamoDB. + DynamoDB uses the service-linked role **AWSServiceRoleForDynamoDBReplication** for global tables replication across AWS Regions. See [DynamoDB global tables security](globaltables-security.md) for more information about the **AWSServiceRoleForDynamoDBReplication** service-linked role. + DynamoDB Accelerator (DAX) uses the service-linked role** AWSServiceRoleForDAX** for configuring and maintaining a DAX cluster. See [Using service-linked IAM roles for DAX](using-service-linked-roles.md) for more information about the **AWSServiceRoleForDAX** service-linked role. In addition to these DynamoDB service-linked roles, DynamoDB uses the Application Auto Scaling service for automatically managing throughput settings on provisioned capacity mode tables. The Application Auto Scaling service uses the service-linked role** AWSServiceRoleForApplicationAutoScaling\$1DynamoDBTable** to manage throughput settings on DynamoDB tables that have auto scaling enabled. See [Service-linked roles for Application Auto Scaling](https://docs.aws.amazon.com/autoscaling/application/userguide/application-auto-scaling-service-linked-roles.html) for more information. # Identity-based policy examples for Amazon DynamoDB By default, users and roles don't have permission to create or modify DynamoDB resources. To grant users permission to perform actions on the resources that they need, an IAM administrator can create IAM policies. To learn how to create an IAM identity-based policy by using these example JSON policy documents, see [Create IAM policies (console)](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_create-console.html) in the *IAM User Guide*. For details about actions and resource types defined by DynamoDB, including the format of the ARNs for each of the resource types, see [Actions, resources, and condition keys for Amazon DynamoDB](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazondynamodb.html) in the *Service Authorization Reference*. **Topics** + [Policy best practices](#security_iam_service-with-iam-policy-best-practices) + [Using the DynamoDB console](#security_iam_id-based-policy-examples-console) + [Allow users to view their own permissions](#security_iam_id-based-policy-examples-view-own-permissions) + [Using identity-based policies with Amazon DynamoDB](using-identity-based-policies.md) ## Policy best practices Identity-based policies determine whether someone can create, access, or delete DynamoDB resources in your account. These actions can incur costs for your AWS account. When you create or edit identity-based policies, follow these guidelines and recommendations: + **Get started with AWS managed policies and move toward least-privilege permissions** – To get started granting permissions to your users and workloads, use the *AWS managed policies* that grant permissions for many common use cases. They are available in your AWS account. We recommend that you reduce permissions further by defining AWS customer managed policies that are specific to your use cases. For more information, see [AWS managed policies](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_managed-vs-inline.html#aws-managed-policies) or [AWS managed policies for job functions](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_job-functions.html) in the *IAM User Guide*. + **Apply least-privilege permissions** – When you set permissions with IAM policies, grant only the permissions required to perform a task. You do this by defining the actions that can be taken on specific resources under specific conditions, also known as *least-privilege permissions*. For more information about using IAM to apply permissions, see [ Policies and permissions in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies.html) in the *IAM User Guide*. + **Use conditions in IAM policies to further restrict access** – You can add a condition to your policies to limit access to actions and resources. For example, you can write a policy condition to specify that all requests must be sent using SSL. You can also use conditions to grant access to service actions if they are used through a specific AWS service, such as CloudFormation. For more information, see [ IAM JSON policy elements: Condition](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html) in the *IAM User Guide*. + **Use IAM Access Analyzer to validate your IAM policies to ensure secure and functional permissions** – IAM Access Analyzer validates new and existing policies so that the policies adhere to the IAM policy language (JSON) and IAM best practices. IAM Access Analyzer provides more than 100 policy checks and actionable recommendations to help you author secure and functional policies. For more information, see [Validate policies with IAM Access Analyzer](https://docs.aws.amazon.com/IAM/latest/UserGuide/access-analyzer-policy-validation.html) in the *IAM User Guide*. + **Require multi-factor authentication (MFA)** – If you have a scenario that requires IAM users or a root user in your AWS account, turn on MFA for additional security. To require MFA when API operations are called, add MFA conditions to your policies. For more information, see [ Secure API access with MFA](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_mfa_configure-api-require.html) in the *IAM User Guide*. For more information about best practices in IAM, see [Security best practices in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html) in the *IAM User Guide*. ## Using the DynamoDB console To access the Amazon DynamoDB console, you must have a minimum set of permissions. These permissions must allow you to list and view details about the DynamoDB resources in your AWS account. If you create an identity-based policy that is more restrictive than the minimum required permissions, the console won't function as intended for entities (users or roles) with that policy. You don't need to allow minimum console permissions for users that are making calls only to the AWS CLI or the AWS API. Instead, allow access to only the actions that match the API operation that they're trying to perform. To ensure that users and roles can still use the DynamoDB console, also attach the DynamoDB `ConsoleAccess` or `ReadOnly` AWS managed policy to the entities. For more information, see [Adding permissions to a user](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_users_change-permissions.html#users_change_permissions-add-console) in the *IAM User Guide*. ## Allow users to view their own permissions This example shows how you might create a policy that allows IAM users to view the inline and managed policies that are attached to their user identity. This policy includes permissions to complete this action on the console or programmatically using the AWS CLI or AWS API. ``` { "Version": "2012-10-17", "Statement": [ { "Sid": "ViewOwnUserInfo", "Effect": "Allow", "Action": [ "iam:GetUserPolicy", "iam:ListGroupsForUser", "iam:ListAttachedUserPolicies", "iam:ListUserPolicies", "iam:GetUser" ], "Resource": ["arn:aws:iam::*:user/${aws:username}"] }, { "Sid": "NavigateInConsole", "Effect": "Allow", "Action": [ "iam:GetGroupPolicy", "iam:GetPolicyVersion", "iam:GetPolicy", "iam:ListAttachedGroupPolicies", "iam:ListGroupPolicies", "iam:ListPolicyVersions", "iam:ListPolicies", "iam:ListUsers" ], "Resource": "*" } ] } ``` # Using identity-based policies with Amazon DynamoDB This topic covers using identity-based AWS Identity and Access Management (IAM) policies with Amazon DynamoDB and provides examples. The examples show how an account administrator can attach permissions policies to IAM identities (users, groups, and roles) and thereby grant permissions to perform operations on Amazon DynamoDB resources. The sections in this topic cover the following: + [IAM permissions required to use the Amazon DynamoDB console](#console-permissions) + [AWS managed (predefined) IAM policies for Amazon DynamoDB](#access-policy-examples-aws-managed) + [Customer managed policy examples](#access-policy-examples-for-sdk-cli) The following is an example of a permissions policy. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "DescribeQueryScanBooksTable", "Effect": "Allow", "Action": [ "dynamodb:DescribeTable", "dynamodb:Query", "dynamodb:Scan" ], "Resource": "arn:aws:dynamodb:us-west-2:111122223333:table/Books" } ] } ``` ------ The preceding policy has one statement that grants permissions for three DynamoDB actions (`dynamodb:DescribeTable`, `dynamodb:Query`, and `dynamodb:Scan`) on a table in the `us-west-2` AWS Region, which is owned by the AWS account specified by `account-id`. The *Amazon Resource Name (ARN)* in the `Resource` value specifies the table that the permissions apply to. ## IAM permissions required to use the Amazon DynamoDB console To work with the DynamoDB console, a user must have a minimum set of permissions that allow the user to work with their AWS account's DynamoDB resources. In addition to these DynamoDB permissions, the console requires permissions: + Amazon CloudWatch permissions to display metrics and graphs. + AWS Data Pipeline permissions to export and import DynamoDB data. + AWS Identity and Access Management permissions to access roles necessary for exports and imports. + Amazon Simple Notification Service permissions to notify you whenever a CloudWatch alarm is triggered. + AWS Lambda permissions to process DynamoDB Streams records. If you create an IAM policy that is more restrictive than the minimum required permissions, the console won't function as intended for users with that IAM policy. To ensure that those users can still use the DynamoDB console, also attach the `AmazonDynamoDBReadOnlyAccess` AWS managed policy to the user, as described in [AWS managed (predefined) IAM policies for Amazon DynamoDB](#access-policy-examples-aws-managed). You don't need to allow minimum console permissions for users who are making calls only to the AWS CLI or the Amazon DynamoDB API. **Note** If you refer to a VPC endpoint, you will also need to authorize the DescribeEndpoints API call for the requesting IAM principal(s) with the IAM action (dynamodb:DescribeEndpoints). For more information see [Required policy for endpoints](inter-network-traffic-privacy.md#inter-network-traffic-DescribeEndpoints). ## AWS managed (predefined) IAM policies for Amazon DynamoDB AWS addresses some common use cases by providing standalone IAM policies that are created and administered by AWS. These AWS managed policies grant necessary permissions for common use cases so that you can avoid having to investigate which permissions are needed. For more information, see [AWS Managed Policies](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_managed-vs-inline.html#aws-managed-policies) in the *IAM User Guide*. The following AWS managed policies, which you can attach to users in your account, are specific to DynamoDB and are grouped by use-case scenario: + **AmazonDynamoDBReadOnlyAccess** – Grants read-only access to DynamoDB resources through the AWS Management Console. + **AmazonDynamoDBFullAccess** – Grants full access to DynamoDB resources through the AWS Management Console. You can review these AWS managed permissions policies by signing in to the IAM console and searching for specific policies there. **Important** The best practice is to create custom IAM policies that grant [least-privilege ](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege) to the users, roles, or groups that require them. ## Customer managed policy examples In this section, you can find policy examples that grant permissions for various DynamoDB actions. These policies work when you use AWS SDKs or the AWS CLI. When you use the console, you need to grant additional permissions that are specific to the console. For more information, see [IAM permissions required to use the Amazon DynamoDB console](#console-permissions). **Note** All of the following policy examples use one of the AWS Regions and contain fictitious account IDs and table names. Examples: + [IAM policy to grant permissions to all DynamoDB actions on a table](grant-permissions-to-any-action-on-table.md) + [IAM policy to grant read-only permissions on items in a DynamoDB table](read-only-permissions-on-table-items.md) + [IAM policy to grant access to a specific DynamoDB table and its indexes](iam-policy-specific-table-indexes.md) + [IAM policy to read, write, update, and delete access on a DynamoDB table](iam-policy-example-data-crud.md) + [IAM policy to separate DynamoDB environments in the same AWS account](iam-policy-separate-environments.md) + [IAM policy to prevent the purchase of DynamoDB reserved capacity](iam-prevent-purchase-reserved-capacity.md) + [IAM policy to grant read access for a DynamoDB stream only (not for the table)](iam-policy-read-stream-only.md) + [IAM policy to allow an AWS Lambda function to access DynamoDB stream records](iam-policy-example-lamda-process-dynamodb-streams.md) + [IAM policy for read and write access to a DynamoDB Accelerator (DAX) cluster](iam-policy-example-read-write-dax-access.md) The *IAM User Guide*, includes [three additional DynamoDB examples](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_examples.html): + [Amazon DynamoDB: Allows Access to a Specific Table](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_dynamodb_specific-table.html) + [Amazon DynamoDB: Allows Access to Specific Columns](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_dynamodb_columns.html) + [Amazon DynamoDB: Allows Row-Level Access to DynamoDB Based on an Amazon Cognito ID](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_examples_dynamodb_rows.html) # IAM policy to grant permissions to all DynamoDB actions on a table The following policy grants permissions for *all* DynamoDB actions on a table called `Books`. The resource ARN specified in the `Resource` identifies a table in a specific AWS Region. If you replace the table name `Books` in the `Resource` ARN with a wildcard character (\$1), *all* DynamoDB actions are allowed on *all* tables in the account. Carefully consider the possible security implications before using a wildcard character on this or any IAM policy. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AllAPIActionsOnBooks", "Effect": "Allow", "Action": "dynamodb:*", "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/Books" } ] } ``` ------ **Note** This is an example of using a wildcard character (\$1) to allow *all* actions, including administration, data operations, monitoring, and purchase of DynamoDB reserved capacity. Instead, it is a best practice to explicitly specify each action to be granted and only what that user, role, or group needs. # IAM policy to grant read-only permissions on items in a DynamoDB table The following permissions policy grants permissions for the `GetItem`, `BatchGetItem`, `Scan`, `Query`, and `ConditionCheckItem` DynamoDB actions only, and as a result, sets read-only access on the `Books` table. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "ReadOnlyAPIActionsOnBooks", "Effect": "Allow", "Action": [ "dynamodb:GetItem", "dynamodb:BatchGetItem", "dynamodb:Scan", "dynamodb:Query", "dynamodb:ConditionCheckItem" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/Books" } ] } ``` ------ # IAM policy to grant access to a specific DynamoDB table and its indexes The following policy grants permissions for data modification actions on a DynamoDB table called `Books` and all of that table's indexes. For more information about how indexes work, see [Improving data access with secondary indexes in DynamoDB](SecondaryIndexes.md). ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AccessTableAllIndexesOnBooks", "Effect": "Allow", "Action": [ "dynamodb:PutItem", "dynamodb:UpdateItem", "dynamodb:DeleteItem", "dynamodb:BatchWriteItem", "dynamodb:GetItem", "dynamodb:BatchGetItem", "dynamodb:Scan", "dynamodb:Query", "dynamodb:ConditionCheckItem" ], "Resource": [ "arn:aws:dynamodb:us-west-2:123456789012:table/Books", "arn:aws:dynamodb:us-west-2:123456789012:table/Books/index/*" ] } ] } ``` ------ # IAM policy to read, write, update, and delete access on a DynamoDB table Use this policy if you need to allow your application to create, read, update, and delete data in Amazon DynamoDB tables, indexes, and streams. Substitute the AWS Region name, your account ID, and the table name or wildcard character (\$1) where appropriate. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "DynamoDBIndexAndStreamAccess", "Effect": "Allow", "Action": [ "dynamodb:GetShardIterator", "dynamodb:Scan", "dynamodb:Query", "dynamodb:DescribeStream", "dynamodb:GetRecords", "dynamodb:ListStreams" ], "Resource": [ "arn:aws:dynamodb:us-west-2:123456789012:table/Books/index/*", "arn:aws:dynamodb:us-west-2:123456789012:table/Books/stream/*" ] }, { "Sid": "DynamoDBTableAccess", "Effect": "Allow", "Action": [ "dynamodb:BatchGetItem", "dynamodb:BatchWriteItem", "dynamodb:ConditionCheckItem", "dynamodb:PutItem", "dynamodb:DescribeTable", "dynamodb:DeleteItem", "dynamodb:GetItem", "dynamodb:Scan", "dynamodb:Query", "dynamodb:UpdateItem" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/Books" }, { "Sid": "DynamoDBDescribeLimitsAccess", "Effect": "Allow", "Action": "dynamodb:DescribeLimits", "Resource": [ "arn:aws:dynamodb:us-west-2:123456789012:table/Books", "arn:aws:dynamodb:us-west-2:123456789012:table/Books/index/*" ] } ] } ``` ------ To expand this policy to cover all DynamoDB tables in all AWS Regions for this account, use a wildcard (\$1) for the Region and table name. For example: ``` "Resource":[ "arn:aws:dynamodb:*:123456789012:table/*", "arn:aws:dynamodb:*:123456789012:table/*/index/*" ] ``` # IAM policy to separate DynamoDB environments in the same AWS account Suppose that you have separate environments where each environment maintains its own version of a table named `ProductCatalog`. If you create two `ProductCatalog` tables in the same AWS account, work in one environment might affect the other environment because of the way that permissions are set up. For example, quotas on the number of concurrent control plane operations (such as `CreateTable`) are set at the AWS account level. As a result, each action in one environment reduces the number of operations available in the other environment. There is also a risk that the code in one environment might accidentally access tables in the other environment. **Note** If you want to separate production and test workloads to help control an event's potential "blast radius," the best practice is to create separate AWS accounts for test and production workloads. For more information, see [AWS Account Management and Separation](https://docs.aws.amazon.com//wellarchitected/latest/security-pillar/aws-account-management-and-separation.html). Suppose further that you have two developers, Amit and Alice, who are testing the `ProductCatalog` table. Instead of each developer requiring a separate AWS account, your developers can share the same test AWS account. In this test account, you can create a copy of the same table for each developer to work on, such as `Alice_ProductCatalog` and `Amit_ProductCatalog`. In this case, you can create users Alice and Amit in the AWS account that you created for the test environment. You then can grant permissions to these users to perform DynamoDB actions on the tables that they own. To grant these IAM user permissions, you can do either of the following: + Create a separate policy for each user, and then attach each policy to its user separately. For example, you can attach the following policy to user Alice to allow her access to DynamoDB actions on the `Alice_ProductCatalog` table: ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AllAPIActionsOnAliceTable", "Effect": "Allow", "Action": [ "dynamodb:DeleteItem", "dynamodb:DescribeContributorInsights", "dynamodb:RestoreTableToPointInTime", "dynamodb:ListTagsOfResource", "dynamodb:CreateTableReplica", "dynamodb:UpdateContributorInsights", "dynamodb:CreateBackup", "dynamodb:DeleteTable", "dynamodb:UpdateTableReplicaAutoScaling", "dynamodb:UpdateContinuousBackups", "dynamodb:TagResource", "dynamodb:DescribeTable", "dynamodb:GetItem", "dynamodb:DescribeContinuousBackups", "dynamodb:BatchGetItem", "dynamodb:UpdateTimeToLive", "dynamodb:BatchWriteItem", "dynamodb:ConditionCheckItem", "dynamodb:UntagResource", "dynamodb:PutItem", "dynamodb:Scan", "dynamodb:Query", "dynamodb:UpdateItem", "dynamodb:DeleteTableReplica", "dynamodb:DescribeTimeToLive", "dynamodb:RestoreTableFromBackup", "dynamodb:UpdateTable", "dynamodb:DescribeTableReplicaAutoScaling", "dynamodb:GetShardIterator", "dynamodb:DescribeStream", "dynamodb:GetRecords", "dynamodb:DescribeLimits", "dynamodb:ListStreams" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/Alice_ProductCatalog/*" } ] } ``` ------ Then, you can create a similar policy with a different resource (the `Amit_ProductCatalog` table) for user Amit. + Instead of attaching policies to individual users, you can use IAM policy variables to write a single policy and attach it to a group. You need to create a group and, for this example, add both users Alice and Amit to the group. The following example grants permissions to perform all DynamoDB actions on the `${aws:username}_ProductCatalog` table. The policy variable `${aws:username}` is replaced by the requester's user name when the policy is evaluated. For example, if Alice sends a request to add an item, the action is allowed only if Alice is adding items to the `Alice_ProductCatalog` table. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "ActionsOnUserSpecificTable", "Effect": "Allow", "Action": [ "dynamodb:PutItem", "dynamodb:UpdateItem", "dynamodb:DeleteItem", "dynamodb:BatchWriteItem", "dynamodb:GetItem", "dynamodb:BatchGetItem", "dynamodb:Scan", "dynamodb:Query", "dynamodb:ConditionCheckItem" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/${aws:username}_ProductCatalog" }, { "Sid": "AdditionalPrivileges", "Effect": "Allow", "Action": [ "dynamodb:ListTables", "dynamodb:DescribeTable", "dynamodb:DescribeContributorInsights" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/*" } ] } ``` ------ **Note** When using IAM policy variables, you must explicitly specify the `2012-10-17` version of the IAM policy language in the policy. The default version of the IAM policy language (`2008-10-17`) does not support policy variables. Instead of identifying a specific table as a resource as you normally would, you could use a wildcard character (\$1) to grant permissions on all tables where the table name is prefixed with the user that is making the request, as shown in the following example. ``` "Resource":"arn:aws:dynamodb:us-west-2:123456789012:table/${aws:username}_*" ``` # IAM policy to prevent the purchase of DynamoDB reserved capacity With Amazon DynamoDB reserved capacity, you pay a one-time, upfront fee and commit to paying for a minimum usage level at significant savings over a period of time. You can use the AWS Management Console to view and purchase reserved capacity. However, you might not want all of the users in your organization to be able to purchase reserved capacity. For more information about reserved capacity, see [Amazon DynamoDB pricing](https://aws.amazon.com/dynamodb/pricing). DynamoDB provides the following API operations for controlling access to reserved capacity management: + `dynamodb:DescribeReservedCapacity` – Returns the reserved capacity purchases that are currently in effect. + `dynamodb:DescribeReservedCapacityOfferings` – Returns details about the reserved capacity plans that are currently offered by AWS. + `dynamodb:PurchaseReservedCapacityOfferings` – Performs an actual purchase of reserved capacity. The AWS Management Console uses these API actions to display reserved capacity information and make purchases. You cannot call these operations from an application program because they can be accessed only from the console. However, you can allow or deny access to these operations in an IAM permissions policy. The following policy allows users to view reserved capacity purchases and offerings by using the AWS Management Console — but new purchases are denied. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AllowReservedCapacityDescriptions", "Effect": "Allow", "Action": [ "dynamodb:DescribeReservedCapacity", "dynamodb:DescribeReservedCapacityOfferings" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:*" }, { "Sid": "DenyReservedCapacityPurchases", "Effect": "Deny", "Action": "dynamodb:PurchaseReservedCapacityOfferings", "Resource": "arn:aws:dynamodb:us-west-2:123456789012:*" } ] } ``` ------ Note that this policy uses the wildcard character (\$1) to allow describe permissions for all, and to deny the purchase of DynamoDB reserved capacity for all. # IAM policy to grant read access for a DynamoDB stream only (not for the table) When you enable DynamoDB Streams on a table, information is captured about every modification to items in the table. For more information, see [Change data capture for DynamoDB Streams](Streams.md). In some cases, you might want to prevent an application from reading data from a DynamoDB table, but still allow access to that table's streams. For example, you can configure AWS Lambda to poll a stream and invoke a Lambda function when item updates are detected, and then perform additional processing. The following actions are available for controlling access to DynamoDB streams: + `dynamodb:DescribeStream` + `dynamodb:GetRecords` + `dynamodb:GetShardIterator` + `dynamodb:ListStreams` The following example policy grants users permissions to access the streams of a table named `GameScores`. The wildcard character (\$1) in the ARN matches any stream associated with that table. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AccessGameScoresStreamOnly", "Effect": "Allow", "Action": [ "dynamodb:DescribeStream", "dynamodb:GetRecords", "dynamodb:GetShardIterator", "dynamodb:ListStreams" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/GameScores/stream/*" } ] } ``` ------ Note that this policy grants access to the `GameScores` table's streams, but not to the table itself. # IAM policy to allow an AWS Lambda function to access DynamoDB stream records If you want certain actions to be performed based on events in a DynamoDB stream, you can write an AWS Lambda function that is triggered by these events. A Lambda function such as this needs permissions to read data from a DynamoDB stream. For more information about using Lambda with DynamoDB Streams, see [DynamoDB Streams and AWS Lambda triggers](Streams.Lambda.md). To grant permissions to Lambda, use the permissions policy that is associated with the Lambda function's IAM role (also known as an execution role). Specify this policy when you create the Lambda function. For example, you can associate the following permissions policy with an execution role to grant Lambda permissions to perform the DynamoDB Streams actions listed. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "APIAccessForDynamoDBStreams", "Effect": "Allow", "Action": [ "dynamodb:GetRecords", "dynamodb:GetShardIterator", "dynamodb:DescribeStream", "dynamodb:ListStreams" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:table/GameScores/stream/*" } ] } ``` ------ For more information, see [AWS Lambda permissions ](https://docs.aws.amazon.com/lambda/latest/dg/intro-permission-model.html) in the *AWS Lambda Developer Guide*. # IAM policy for read and write access to a DynamoDB Accelerator (DAX) cluster The following policy allows read, write, update, and delete access to a DynamoDB Accelerator (DAX) cluster, but not to the associated DynamoDB table. To use this policy, substitute the AWS Region name, your account ID, and the name of your DAX cluster. **Note** This policy gives access to DAX cluster, but not to the associated DynamoDB table. Make sure that your DAX cluster has the correct policy to perform these same operations on the DynamoDB table on your behalf. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AmazonDynamoDBDAXDataOperations", "Effect": "Allow", "Action": [ "dax:GetItem", "dax:PutItem", "dax:ConditionCheckItem", "dax:BatchGetItem", "dax:BatchWriteItem", "dax:DeleteItem", "dax:Query", "dax:UpdateItem", "dax:Scan" ], "Resource": "arn:aws:dax:eu-west-1:123456789012:cache/MyDAXCluster" } ] } ``` ------ To expand this policy to cover DAX access for all AWS Regions for an account, use a wildcard character (\$1) for the Region name. ``` "Resource": "arn:aws:dax:*:123456789012:cache/MyDAXCluster" ``` # Troubleshooting Amazon DynamoDB identity and access Use the following information to help you diagnose and fix common issues that you might encounter when working with DynamoDB and IAM. **Topics** + [I am not authorized to perform an action in DynamoDB](#security_iam_troubleshoot-no-permissions) + [I am not authorized to perform iam:PassRole](#security_iam_troubleshoot-passrole) + [I want to allow people outside of my AWS account to access my DynamoDB resources](#security_iam_troubleshoot-cross-account-access) ## I am not authorized to perform an action in DynamoDB If the AWS Management Console tells you that you're not authorized to perform an action, then you must contact your administrator for assistance. Your administrator is the person that provided you with your user name and password. The following example error occurs when the `mateojackson` user tries to use the console to view details about a fictional `my-example-widget` resource but does not have the fictional `aws:GetWidget` permissions. ``` User: arn:aws:iam::123456789012:user/mateojackson is not authorized to perform: aws:GetWidget on resource: my-example-widget ``` In this case, Mateo asks his administrator to update his policies to allow him to access the `my-example-widget` resource using the `aws:GetWidget` action. ## I am not authorized to perform iam:PassRole If you receive an error that you're not authorized to perform the `iam:PassRole` action, your policies must be updated to allow you to pass a role to DynamoDB. Some AWS services allow you to pass an existing role to that service instead of creating a new service role or service-linked role. To do this, you must have permissions to pass the role to the service. The following example error occurs when an IAM user named `marymajor` tries to use the console to perform an action in DynamoDB. However, the action requires the service to have permissions that are granted by a service role. Mary does not have permissions to pass the role to the service. ``` User: arn:aws:iam::123456789012:user/marymajor is not authorized to perform: iam:PassRole ``` In this case, Mary's policies must be updated to allow her to perform the `iam:PassRole` action. If you need help, contact your AWS administrator. Your administrator is the person who provided you with your sign-in credentials. ## I want to allow people outside of my AWS account to access my DynamoDB resources You can create a role that users in other accounts or people outside of your organization can use to access your resources. You can specify who is trusted to assume the role. For services that support resource-based policies or access control lists (ACLs), you can use those policies to grant people access to your resources. To learn more, consult the following: + To learn whether DynamoDB supports these features, see [How Amazon DynamoDB works with IAM](security_iam_service-with-iam.md). + To learn how to provide access to your resources across AWS accounts that you own, see [Providing access to an IAM user in another AWS account that you own](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_common-scenarios_aws-accounts.html) in the *IAM User Guide*. + To learn how to provide access to your resources to third-party AWS accounts, see [Providing access to AWS accounts owned by third parties](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_common-scenarios_third-party.html) in the *IAM User Guide*. + To learn how to provide access through identity federation, see [Providing access to externally authenticated users (identity federation)](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_common-scenarios_federated-users.html) in the *IAM User Guide*. + To learn the difference between using roles and resource-based policies for cross-account access, see [Cross account resource access in IAM](https://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies-cross-account-resource-access.html) in the *IAM User Guide*. # IAM policy to prevent the purchase of DynamoDB reserved capacity With Amazon DynamoDB reserved capacity, you pay a one-time, upfront fee and commit to paying for a minimum usage level at significant savings over a period of time. You can use the AWS Management Console to view and purchase reserved capacity. However, you might not want all of the users in your organization to be able to purchase reserved capacity. For more information about reserved capacity, see [Amazon DynamoDB pricing](https://aws.amazon.com/dynamodb/pricing). DynamoDB provides the following API operations for controlling access to reserved capacity management: + `dynamodb:DescribeReservedCapacity` – Returns the reserved capacity purchases that are currently in effect. + `dynamodb:DescribeReservedCapacityOfferings` – Returns details about the reserved capacity plans that are currently offered by AWS. + `dynamodb:PurchaseReservedCapacityOfferings` – Performs an actual purchase of reserved capacity. The AWS Management Console uses these API actions to display reserved capacity information and make purchases. You cannot call these operations from an application program because they can be accessed only from the console. However, you can allow or deny access to these operations in an IAM permissions policy. The following policy allows users to view reserved capacity purchases and offerings by using the AWS Management Console — but new purchases are denied. ------ #### [ JSON ] **** ``` { "Version":"2012-10-17", "Statement": [ { "Sid": "AllowReservedCapacityDescriptions", "Effect": "Allow", "Action": [ "dynamodb:DescribeReservedCapacity", "dynamodb:DescribeReservedCapacityOfferings" ], "Resource": "arn:aws:dynamodb:us-west-2:123456789012:*" }, { "Sid": "DenyReservedCapacityPurchases", "Effect": "Deny", "Action": "dynamodb:PurchaseReservedCapacityOfferings", "Resource": "arn:aws:dynamodb:us-west-2:123456789012:*" } ] } ``` ------ Note that this policy uses the wildcard character (\$1) to allow describe permissions for all, and to deny the purchase of DynamoDB reserved capacity for all.