Identity and Access Management in Amazon Elasticsearch Service - Amazon Elasticsearch Service

Identity and Access Management in Amazon Elasticsearch Service

Amazon Elasticsearch Service offers several ways of controlling access to your domains. This section covers the various policy types, how they interact with each other, and how to create your own, custom policies.

Important

VPC support introduces some additional considerations to Amazon ES access control. For more information, see About Access Policies on VPC Domains.

Types of Policies

Amazon ES supports three types of access policies:

Resource-based Policies

You add a resource-based policy, often called the domain access policy, when you create a domain. These policies specify which actions a principal can perform on the domain's subresources. Subresources include Elasticsearch indices and APIs.

The Principal element specifies the accounts, users, or roles that are allowed access. The Resource element specifies which subresources these principals can access. The following resource-based policy grants test-user full access (es:*) to the subresources on test-domain:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": [ "arn:aws:iam::123456789012:user/test-user" ] }, "Action": [ "es:*" ], "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/*" } ] }

Two important considerations apply to this policy:

  • These privileges apply only to this domain. Unless you create similar policies on other domains, test-user can only access test-domain.

  • The trailing /* in the Resource element is significant and indicates that resource-based policies only apply to the domain's subresources, not the domain itself. In resource-based policies, the es:* action is equivalent to es:ESHttp*.

    For example, test-user can make requests against an index (GET https://search-test-domain.us-west-1.es.amazonaws.com/test-index), but can't update the domain's configuration (POST https://es.us-west-1.amazonaws.com/2015-01-01/es/domain/test-domain/config). Note the difference between the two endpoints. Accessing the configuration API requires an identity-based policy.

To further restrict test-user, you can apply the following policy:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": [ "arn:aws:iam::123456789012:user/test-user" ] }, "Action": [ "es:ESHttpGet" ], "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/test-index/_search" } ] }

Now test-user can perform only one operation: searches against test-index. All other indices within the domain are inaccessible, and without permissions to use the es:ESHttpPut or es:ESHttpPost actions, test-user can't add or modify documents.

Next, you might decide to configure a role for power users. This policy gives power-user-role access to the HTTP GET and PUT methods for all URIs in the index:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": [ "arn:aws:iam::123456789012:role/power-user-role" ] }, "Action": [ "es:ESHttpGet", "es:ESHttpPut" ], "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/test-index/*" } ] }

If your domain is in a VPC or uses fine-grained access control, you can use an open domain access policy. Otherwise, your domain access policy must contain some restriction, either by principal or IP address.

For information about all available actions, see Policy Element Reference. For far more granular control over your data, use an open domain access policy with fine-grained access control.

Identity-based Policies

Unlike resource-based policies, which are a part of each Amazon ES domain, you attach identity-based policies to users or roles using the AWS Identity and Access Management (IAM) service. Just like resource-based policies, identity-based policies specify who can access a service, which actions they can perform, and if applicable, the resources on which they can perform those actions.

While they certainly don't have to be, identity-based policies tend to be more generic. They often govern only the configuration API actions a user can perform. After you have these policies in place, you can use resource-based policies (or fine-grained access control) in Amazon ES to offer users access to Elasticsearch indices and APIs.

Note

Users with the AWS managed AmazonESReadOnlyAccess policy can't see cluster health status on the console. To allow them to see cluster health status (and other Elasticsearch data), add the es:ESHttpGet action to an access policy and attach it to their accounts or roles.

Because identity-based policies attach to users or roles (principals), the JSON doesn't specify a principal. The following policy grants access to actions that begin with Describe and List. This combination of actions provides read-only access to domain configurations, but not to the data stored in the domain itself:

{ "Version": "2012-10-17", "Statement": [ { "Action": [ "es:Describe*", "es:List*" ], "Effect": "Allow", "Resource": "*" } ] }

An administrator might have full access to Amazon ES and all data stored on all domains:

{ "Version": "2012-10-17", "Statement": [ { "Action": [ "es:*" ], "Effect": "Allow", "Resource": "*" } ] }

Identity-based policies let you use tags to control access to the configuration API (not the Elasticsearch APIs). The following policy, for example, lets attached principals view and update a domain's configuration if the domain has the team:devops tag:

{ "Version": "2012-10-17", "Statement": [{ "Action": [ "es:UpdateElasticsearchDomainConfig", "es:DescribeElasticsearchDomain", "es:DescribeElasticsearchDomainConfig" ], "Effect": "Allow", "Resource": "*", "Condition": { "ForAnyValue:StringEquals": { "aws:ResourceTag/team": [ "devops" ] } } }] }

Similarly, Amazon ES supports the RequestTag and TagKeys global condition keys for the configuration API. These conditions only apply to API calls that include tags within the request, such as CreateElasticsearchDomain, AddTags, and RemoveTags. The following policy lets attached principals create domains, but only if they include the team:it tag in the request:

{ "Version": "2012-10-17", "Statement": { "Effect": "Allow", "Action": [ "es:CreateElasticsearchDomain", "es:AddTags" ], "Resource": "*", "Condition": { "StringEquals": { "aws:RequestTag/team": [ "it" ] } } } }

For more details on using tags for access control and the differences between resource-based and identity-based policies, see the IAM User Guide.

IP-based Policies

IP-based policies restrict access to a domain to one or more IP addresses or CIDR blocks. Technically, IP-based policies are not a distinct type of policy. Instead, they are just resource-based policies that specify an anonymous principal and include a special Condition element.

The primary appeal of IP-based policies is that they allow unsigned requests to an Amazon ES domain, which lets you use clients like curl and Kibana or access the domain through a proxy server. To learn more, see Using a Proxy to Access Amazon ES from Kibana.

Note

If you enabled VPC access for your domain, you can't configure an IP-based policy. Instead, you can use security groups to control which IP addresses can access the domain. For more information, see About Access Policies on VPC Domains.

The following policy grants all HTTP requests that originate from the specified IP range access to test-domain:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": "*" }, "Action": [ "es:ESHttp*" ], "Condition": { "IpAddress": { "aws:SourceIp": [ "192.0.2.0/24" ] } }, "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/*" } ] }

If your domain has a public endpoint and doesn't use fine-grained access control, we recommend combining IAM principals and IP addresses. This policy grants test-user HTTP access only if the request originates from the specified IP range:

{ "Version": "2012-10-17", "Statement": [{ "Effect": "Allow", "Principal": { "AWS": [ "arn:aws:iam::987654321098:user/test-user" ] }, "Action": [ "es:ESHttp*" ], "Condition": { "IpAddress": { "aws:SourceIp": [ "192.0.2.0/24" ] } }, "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/*" }] }

Making and Signing Amazon ES Requests

Even if you configure a completely open resource-based access policy, all requests to the Amazon ES configuration API must be signed. If your policies specify IAM users or roles, requests to the Elasticsearch APIs also must be signed using AWS Signature Version 4. The signing method differs by API:

  • To make calls to the Amazon ES configuration API, we recommend that you use one of the AWS SDKs. The SDKs greatly simplify the process and can save you a significant amount of time compared to creating and signing your own requests. The configuration API endpoints use the following format:

    es.region.amazonaws.com/2015-01-01/

    For example, the following request makes a configuration change to the movies domain, but you have to sign it yourself (not recommended):

    POST https://es.us-east-1.amazonaws.com/2015-01-01/es/domain/movies/config { "ElasticsearchClusterConfig": { "InstanceType": "c5.xlarge.elasticsearch" } }

    If you use one of the SDKs, such as Boto 3, the SDK automatically handles the request signing:

    import boto3 client = boto3.client('es') response = client.update_elasticsearch_domain_config( DomainName='movies', ElasticsearchClusterConfig={ 'InstanceType': 'c5.xlarge.elasticsearch' } )

    For a Java code sample, see Using the AWS SDKs with Amazon Elasticsearch Service.

  • To make calls to the Elasticsearch APIs, you must sign your own requests. For sample code in a variety of languages, see Signing HTTP Requests to Amazon Elasticsearch Service. The Elasticsearch APIs use the following format:

    domain-id.region.es.amazonaws.com

    For example, the following request searches the movies index for thor:

    GET https://my-domain.us-east-1.es.amazonaws.com/movies/_search?q=thor
Note

The service ignores parameters passed in URLs for HTTP POST requests that are signed with Signature Version 4.

When Policies Collide

Complexities arise when policies disagree or make no explicit mention of a user. Understanding How IAM Works in the IAM User Guide provides a concise summary of policy evaluation logic:

  • By default, all requests are denied.

  • An explicit allow overrides this default.

  • An explicit deny overrides any allows.

For example, if a resource-based policy grants you access to a domain subresource (an Elasticsearch index or API), but an identity-based policy denies you access, you are denied access. If an identity-based policy grants access and a resource-based policy does not specify whether or not you should have access, you are allowed access. See the following table of intersecting policies for a full summary of outcomes for domain subresources.

Allowed in Resource-based Policy Denied in Resource-based Policy Neither Allowed nor Denied in Resource-based Policy
Allowed in Identity-based Policy

Allow

Deny Allow
Denied in Identity-based Policy Deny Deny Deny
Neither Allowed nor Denied in Identity-based Policy Allow Deny Deny

Policy Element Reference

Amazon ES supports most policy elements in the IAM Policy Elements Reference, with the exception of NotPrincipal. The following table shows the most common elements.

JSON Policy Element Summary
Version

The current version of the policy language is 2012-10-17. All access policies should specify this value.

Effect

This element specifies whether the statement allows or denies access to the specified actions. Valid values are Allow or Deny.

Principal

This element specifies the AWS account or IAM user or role that is allowed or denied access to a resource and can take several forms:

  • AWS accounts: "Principal":{"AWS": ["123456789012"]} or "Principal":{"AWS": ["arn:aws:iam::123456789012:root"]}

  • IAM users: "Principal":{"AWS": ["arn:aws:iam::123456789012:user/test-user"]}

  • IAM roles: "Principal":{"AWS": ["arn:aws:iam::123456789012:role/test-role"]}

Specifying the * wildcard enables anonymous access to the domain, which we don't recommend unless you add an IP-based condition, use VPC support, or enable fine-grained access control.

Action

Amazon ES uses the following actions for HTTP methods:

  • es:ESHttpDelete

  • es:ESHttpGet

  • es:ESHttpHead

  • es:ESHttpPost

  • es:ESHttpPut

  • es:ESHttpPatch

Amazon ES uses the following actions for the configuration API:

  • es:AddTags

  • es:AssociatePackage

  • es:CreateElasticsearchDomain

  • es:CreateElasticsearchServiceRole

  • es:CreatePackage

  • es:DeleteElasticsearchDomain

  • es:DeleteElasticsearchServiceRole

  • es:DeletePackage

  • es:DescribeElasticsearchDomain

  • es:DescribeElasticsearchDomainConfig

  • es:DescribeElasticsearchDomains

  • es:DescribeElasticsearchInstanceTypeLimits

  • es:DescribeReservedElasticsearchInstanceOfferings

  • es:DescribeReservedElasticsearchInstances

  • es:DissociatePackage

  • es:ESCrossClusterGet

  • es:GetCompatibleElasticsearchVersions

  • es:ListDomainNames

  • es:ListElasticsearchInstanceTypeDetails

  • es:ListElasticsearchInstanceTypes

  • es:ListElasticsearchVersions

  • es:ListTags

  • es:PurchaseReservedElasticsearchInstanceOffering

  • es:RemoveTags

  • es:UpdateElasticsearchDomainConfig

Tip

You can use wildcards to specify a subset of actions, such as "Action":"es:*" or "Action":"es:Describe*".

Certain es: actions support resource-level permissions. For example, you can give a user permissions to delete one particular domain without giving that user permissions to delete any domain. Other actions apply only to the service itself. For example, es:ListDomainNames makes no sense in the context of a single domain and thus requires a wildcard.

Important

Resource-based policies differ from resource-level permissions. Resource-based policies are full JSON policies that attach to domains. Resource-level permissions let you restrict actions to particular domains or subresources. In practice, you can think of resource-level permissions as an optional part of a resource- or identity-based policy.

The following identity-based policy lists all es: actions and groups them according to whether they apply to the domain subresources (test-domain/*), to the domain configuration (test-domain), or only to the service (*):

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "es:ESHttpDelete", "es:ESHttpGet", "es:ESHttpHead", "es:ESHttpPost", "es:ESHttpPut", "es:ESHttpPatch" ], "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/*" }, { "Effect": "Allow", "Action": [ "es:AssociatePackage", "es:CreateElasticsearchDomain", "es:DeleteElasticsearchDomain", "es:DescribeElasticsearchDomain", "es:DescribeElasticsearchDomainConfig", "es:DescribeElasticsearchDomains", "es:DissociatePackage", "es:ESCrossClusterGet", "es:GetCompatibleElasticsearchVersions", "es:UpdateElasticsearchDomainConfig" ], "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain" }, { "Effect": "Allow", "Action": [ "es:AddTags", "es:CreateElasticsearchServiceRole", "es:CreatePackage", "es:DeleteElasticsearchServiceRole", "es:DeletePackage", "es:DescribeElasticsearchInstanceTypeLimits", "es:DescribeReservedElasticsearchInstanceOfferings", "es:DescribeReservedElasticsearchInstances", "es:ESCrossClusterGet", "es:ListDomainNames", "es:ListElasticsearchInstanceTypeDetails", "es:ListElasticsearchInstanceTypes", "es:ListElasticsearchVersions", "es:ListTags", "es:PurchaseReservedElasticsearchInstanceOffering", "es:RemoveTags" ], "Resource": "*" } ] }
Note

While resource-level permissions for es:CreateElasticsearchDomain might seem unintuitive—after all, why give a user permissions to create a domain that already exists?—the use of a wildcard lets you enforce a simple naming scheme for your domains, such as "Resource": "arn:aws:es:us-west-1:987654321098:domain/my-team-name-*".

Of course, nothing prevents you from including actions alongside less restrictive resource elements, such as the following:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "es:ESHttpGet", "es:DescribeElasticsearchDomain" ], "Resource": "*" } ] }

To learn more about pairing actions and resources, see the Resource element in this table.

Condition

Amazon ES supports most conditions that are described in Available Global Condition Keys in the IAM User Guide. Notable exceptions include the aws:SecureTransport and aws:PrincipalTag keys, which Amazon ES does not support.

When configuring an IP-based policy, you specify the IP addresses or CIDR block as a condition, such as the following:

"Condition": { "IpAddress": { "aws:SourceIp": [ "192.0.2.0/32" ] } }

As noted in Identity-based Policies, the aws:ResourceTag, aws:RequestTag, and aws:TagKeys condition keys only apply to the configuration API, not the Elasticsearch APIs.

Resource

Amazon ES uses Resource elements in three basic ways:

  • For actions that apply to Amazon ES itself, like es:ListDomainNames, or to allow full access, use the following syntax:

    "Resource": "*"
  • For actions that involve a domain's configuration, like es:DescribeElasticsearchDomain, you can use the following syntax:

    "Resource": "arn:aws:es:region:aws-account-id:domain/domain-name"
  • For actions that apply to a domain's subresources, like es:ESHttpGet, you can use the following syntax:

    "Resource": "arn:aws:es:region:aws-account-id:domain/domain-name/*"

    You don't have to use a wildcard. Amazon ES lets you define a different access policy for each Elasticsearch index or API. For example, you might limit a user's permissions to the test-index index:

    "Resource": "arn:aws:es:region:aws-account-id:domain/domain-name/test-index"

    Instead of full access to test-index, you might prefer to limit the policy to just the search API:

    "Resource": "arn:aws:es:region:aws-account-id:domain/domain-name/test-index/_search"

    You can even control access to individual documents:

    "Resource": "arn:aws:es:region:aws-account-id:domain/domain-name/test-index/test-type/1"

    Essentially, if Elasticsearch expresses the subresource as a URI, you can control access to it using an access policy. For even more control over which resources a user can access, see Fine-Grained Access Control in Amazon Elasticsearch Service.

For details about which actions support resource-level permissions, see the Action element in this table.

AWS-Managed Policies

Amazon ES has three AWS-managed, identity-based IAM policies. See Service-Linked Role for VPC Access for a summary of the service-linked role (AWSServiceRoleForAmazonElasticsearchService) that Amazon ES uses to place domains within VPCs.

AWS-Managed Policy Description

AmazonESFullAccess

Provides full access to the Amazon ES configuration API and all HTTP methods for the Elasticsearch APIs. Fine-grained access control and resource-based policies can still restrict access.

AmazonESReadOnlyAccess

Provides read-only access to the Amazon ES configuration API (es:Describe*, es:List*, and es:Get*) and no access to the HTTP methods for the Elasticsearch APIs.

AmazonESCognitoAccess

Provides the minimum Amazon Cognito permissions necessary to enable Amazon Cognito Authentication for Kibana.

Advanced Options and API Considerations

Amazon ES has several advanced options, one of which has access control implications: rest.action.multi.allow_explicit_index. At its default setting of true, it allows users to bypass subresource permissions under certain circumstances.

For example, consider the following resource-based policy:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": [ "arn:aws:iam::123456789012:user/test-user" ] }, "Action": [ "es:ESHttp*" ], "Resource": [ "arn:aws:es:us-west-1:987654321098:domain/test-domain/test-index/*", "arn:aws:es:us-west-1:987654321098:domain/test-domain/_bulk" ] }, { "Effect": "Allow", "Principal": { "AWS": [ "arn:aws:iam::123456789012:user/test-user" ] }, "Action": [ "es:ESHttpGet" ], "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/restricted-index/*" } ] }

This policy grants test-user full access to test-index and the Elasticsearch bulk API. It also allows GET requests to restricted-index.

The following indexing request, as you might expect, fails due to a permissions error:

PUT https://search-test-domain.us-west-1.es.amazonaws.com/restricted-index/movie/1 { "title": "Your Name", "director": "Makoto Shinkai", "year": "2016" }

Unlike the index API, the bulk API lets you create, update, and delete many documents in a single call. You often specify these operations in the request body, however, rather than in the request URL. Because Amazon ES uses URLs to control access to domain subresources, test-user can, in fact, use the bulk API to make changes to restricted-index. Even though the user lacks POST permissions on the index, the following request succeeds:

POST https://search-test-domain.us-west-1.es.amazonaws.com/_bulk { "index" : { "_index": "restricted-index", "_type" : "movie", "_id" : "1" } } { "title": "Your Name", "director": "Makoto Shinkai", "year": "2016" }

In this situation, the access policy fails to fulfill its intent. To prevent users from bypassing these kinds of restrictions, you can change rest.action.multi.allow_explicit_index to false. If this value is false, all calls to the bulk, mget, and msearch APIs that specify index names in the request body stop working. In other words, calls to _bulk no longer work, but calls to test-index/_bulk do. This second endpoint contains an index name, so you don't need to specify one in the request body.

Kibana relies heavily on mget and msearch, so it is unlikely to work properly after this change. For partial remediation, you can leave rest.action.multi.allow_explicit_index as true and deny certain users access to one or more of these APIs.

For information about changing this setting, see Advanced Options.

Similarly, the following resource-based policy contains two subtle issues:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": "arn:aws:iam::123456789012:user/test-user" }, "Action": "es:ESHttp*", "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/*" }, { "Effect": "Deny", "Principal": { "AWS": "arn:aws:iam::123456789012:user/test-user" }, "Action": "es:ESHttp*", "Resource": "arn:aws:es:us-west-1:987654321098:domain/test-domain/restricted-index/*" } ] }
  • Despite the explicit deny, test-user can still make calls such as GET https://search-test-domain.us-west-1.es.amazonaws.com/_all/_search and GET https://search-test-domain.us-west-1.es.amazonaws.com/*/_search to access the documents in restricted-index.

  • Because the Resource element references restricted-index/*, test-user doesn't have permissions to directly access the index's documents. The user does, however, have permissions to delete the entire index. To prevent access and deletion, the policy instead must specify restricted-index*.

Rather than mixing broad allows and focused denies, the safest approach is to follow the principle of least privilege and grant only the permissions that are required to perform a task. For more information about controlling access to individual indices or Elasticsearch operations, see Fine-Grained Access Control in Amazon Elasticsearch Service.

Configuring Access Policies

  • For instructions on creating or modifying resource- and IP-based policies in Amazon ES, see Configuring Access Policies.

  • For instructions on creating or modifying identity-based policies in IAM, see Creating IAM Policies in the IAM User Guide.

Additional Sample Policies

Although this chapter includes many sample policies, AWS access control is a complex subject that is best understood through examples. For more, see Example Policies in the IAM User Guide.