Elasticsearch controls - AWS Security Hub

Elasticsearch controls

These controls are related to Elasticsearch resources.

These controls may not be available in all AWS Regions. For more information, see Availability of controls by Region.

[ES.1] Elasticsearch domains should have encryption at-rest enabled

Related requirements: PCI DSS v3.2.1/3.4, NIST.800-53.r5 CA-9(1), NIST.800-53.r5 CM-3(6), NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-28, NIST.800-53.r5 SC-28(1), NIST.800-53.r5 SC-7(10), NIST.800-53.r5 SI-7(6)

Category: Protect > Data protection > Encryption of data at rest

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-encrypted-at-rest

Schedule type: Periodic

Parameters: None

This control checks whether Elasticsearch domains have encryption at rest configuration enabled. The check fails if encryption at rest is not enabled.

For an added layer of security for your sensitive data in OpenSearch, you should configure your OpenSearch to be encrypted at rest. Elasticsearch domains offer encryption of data at rest. The feature uses AWS KMS to store and manage your encryption keys. To perform the encryption, it uses the Advanced Encryption Standard algorithm with 256-bit keys (AES-256).

To learn more about OpenSearch encryption at rest, see Encryption of data at rest for Amazon OpenSearch Service in the Amazon OpenSearch Service Developer Guide.

Certain instance types, such as t.small and t.medium, don't support encryption of data at rest. For details, see Supported instance types in the Amazon OpenSearch Service Developer Guide.

Remediation

To enable encryption at rest for new and existing Elasticsearch domains, see Enabling encryption of data at rest in the Amazon OpenSearch Service Developer Guide.

[ES.2] Elasticsearch domains should not be publicly accessible

Related requirements: PCI DSS v3.2.1/1.2.1,PCI DSS v3.2.1/1.3.1,PCI DSS v3.2.1/1.3.2,PCI DSS v3.2.1/1.3.4,PCI DSS v3.2.1/1.3.6, NIST.800-53.r5 AC-21, NIST.800-53.r5 AC-3, NIST.800-53.r5 AC-3(7), NIST.800-53.r5 AC-4, NIST.800-53.r5 AC-4(21), NIST.800-53.r5 AC-6, NIST.800-53.r5 SC-7, NIST.800-53.r5 SC-7(11), NIST.800-53.r5 SC-7(16), NIST.800-53.r5 SC-7(20), NIST.800-53.r5 SC-7(21), NIST.800-53.r5 SC-7(3), NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-7(9)

Category: Protect > Secure network configuration > Resources within VPC

Severity: Critical

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-in-vpc-only

Schedule type: Periodic

Parameters: None

This control checks whether Elasticsearch domains are in a VPC. It does not evaluate the VPC subnet routing configuration to determine public access. You should ensure that Elasticsearch domains are not attached to public subnets. See Resource-based policies in the Amazon OpenSearch Service Developer Guide. You should also ensure that your VPC is configured according to the recommended best practices. See Security best practices for your VPC in the Amazon VPC User Guide.

Elasticsearch domains deployed within a VPC can communicate with VPC resources over the private AWS network, without the need to traverse the public internet. This configuration increases the security posture by limiting access to the data in transit. VPCs provide a number of network controls to secure access to Elasticsearch domains, including network ACL and security groups. Security Hub recommends that you migrate public Elasticsearch domains to VPCs to take advantage of these controls.

Remediation

If you create a domain with a public endpoint, you cannot later place it within a VPC. Instead, you must create a new domain and migrate your data. The reverse is also true. If you create a domain within a VPC, it cannot have a public endpoint. Instead, you must either create another domain or disable this control.

See Launching your Amazon OpenSearch Service domains within a VPC in the Amazon OpenSearch Service Developer Guide.

[ES.3] Elasticsearch domains should encrypt data sent between nodes

Related requirements: NIST.800-53.r5 AC-4, NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-23, NIST.800-53.r5 SC-23(3), NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-8, NIST.800-53.r5 SC-8(1), NIST.800-53.r5 SC-8(2)

Category: Protect > Data protection > Encryption of data in transit

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-node-to-node-encryption-check

Schedule type: Change triggered

Parameters: None

This control checks whether an Elasticsearch domain has node-to-node encryption enabled. The control fails if the Elasticsearch domain doesn't have node-to-node encryption enabled. The control also produces failed findings if an Elasticsearch version doesn't support node-to-node encryption checks.

HTTPS (TLS) can be used to help prevent potential attackers from eavesdropping on or manipulating network traffic using person-in-the-middle or similar attacks. Only encrypted connections over HTTPS (TLS) should be allowed. Enabling node-to-node encryption for Elasticsearch domains ensures that intra-cluster communications are encrypted in transit.

There can be a performance penalty associated with this configuration. You should be aware of and test the performance trade-off before enabling this option.

Remediation

For information about enabling node-to-node encryption on new and existing domains, see Enabling node-to-node encryption in the Amazon OpenSearch Service Developer Guide.

[ES.4] Elasticsearch domain error logging to CloudWatch Logs should be enabled

Related requirements: NIST.800-53.r5 AC-2(4), NIST.800-53.r5 AC-4(26), NIST.800-53.r5 AC-6(9), NIST.800-53.r5 AU-10, NIST.800-53.r5 AU-12, NIST.800-53.r5 AU-2, NIST.800-53.r5 AU-3, NIST.800-53.r5 AU-6(3), NIST.800-53.r5 AU-6(4), NIST.800-53.r5 CA-7, NIST.800-53.r5 SC-7(9), NIST.800-53.r5 SI-3(8), NIST.800-53.r5 SI-4(20), NIST.800-53.r5 SI-7(8)

Category: Identify - Logging

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-logs-to-cloudwatch

Schedule type: Change triggered

Parameters:

  • logtype = 'error' (not customizable)

This control checks whether Elasticsearch domains are configured to send error logs to CloudWatch Logs.

You should enable error logs for Elasticsearch domains and send those logs to CloudWatch Logs for retention and response. Domain error logs can assist with security and access audits, and can help to diagnose availability issues.

Remediation

For information on how to enable log publishing, see Enabling log publishing (console) in the Amazon OpenSearch Service Developer Guide.

[ES.5] Elasticsearch domains should have audit logging enabled

Related requirements: NIST.800-53.r5 AC-2(4), NIST.800-53.r5 AC-4(26), NIST.800-53.r5 AC-6(9), NIST.800-53.r5 AU-10, NIST.800-53.r5 AU-12, NIST.800-53.r5 AU-2, NIST.800-53.r5 AU-3, NIST.800-53.r5 AU-6(3), NIST.800-53.r5 AU-6(4), NIST.800-53.r5 CA-7, NIST.800-53.r5 SC-7(9), NIST.800-53.r5 SI-3(8), NIST.800-53.r5 SI-4(20), NIST.800-53.r5 SI-7(8)

Category: Identify > Logging

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-audit-logging-enabled (custom Security Hub rule)

Schedule type: Change triggered

Parameters:

  • cloudWatchLogsLogGroupArnList (not customizable). Security Hub does not populate this parameter. Comma-separated list of CloudWatch Logs log groups that should be configured for audit logs.

    This rule is NON_COMPLIANT if the CloudWatch Logs log group of the Elasticsearch domain is not specified in this parameter list.

This control checks whether Elasticsearch domains have audit logging enabled. This control fails if an Elasticsearch domain does not have audit logging enabled.

Audit logs are highly customizable. They allow you to track user activity on your Elasticsearch clusters, including authentication successes and failures, requests to OpenSearch, index changes, and incoming search queries.

Remediation

For detailed instructions on enabling audit logs, see Enabling audit logs in the Amazon OpenSearch Service Developer Guide.

[ES.6] Elasticsearch domains should have at least three data nodes

Related requirements: NIST.800-53.r5 CP-10, NIST.800-53.r5 CP-6(2), NIST.800-53.r5 SC-36, NIST.800-53.r5 SC-5(2), NIST.800-53.r5 SI-13(5)

Category: Recover > Resilience > High availability

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-data-node-fault-tolerance (custom Security Hub rule)

Schedule type: Change triggered

Parameters: None

This control checks whether Elasticsearch domains are configured with at least three data nodes and zoneAwarenessEnabled is true.

An Elasticsearch domain requires at least three data nodes for high availability and fault-tolerance. Deploying an Elasticsearch domain with at least three data nodes ensures cluster operations if a node fails.

Remediation

To modify the number of data nodes in an Elasticsearch domain
  1. Open the Amazon OpenSearch Service console at https://console.aws.amazon.com/aos/.

  2. Under Domains, choose the name of the domain you want to edit.

  3. Choose Edit domain.

  4. Under Data nodes, set Number of nodes to a number greater than or equal to 3.

    For three Availability Zone deployments, set to a multiple of three to ensure equal distribution across Availability Zones.

  5. Choose Submit.

[ES.7] Elasticsearch domains should be configured with at least three dedicated master nodes

Related requirements: NIST.800-53.r5 CP-10, NIST.800-53.r5 CP-6(2), NIST.800-53.r5 SC-36, NIST.800-53.r5 SC-5(2), NIST.800-53.r5 SI-13(5)

Category: Recover > Resilience > High availability

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Configrule: elasticsearch-primary-node-fault-tolerance (custom Security Hub rule)

Schedule type: Change triggered

Parameters: None

This control checks whether Elasticsearch domains are configured with at least three dedicated primary nodes. This control fails if the domain does not use dedicated primary nodes. This control passes if Elasticsearch domains have five dedicated primary nodes. However, using more than three primary nodes might be unnecessary to mitigate the availability risk, and will result in additional cost.

An Elasticsearch domain requires at least three dedicated primary nodes for high availability and fault-tolerance. Dedicated primary node resources can be strained during data node blue/green deployments because there are additional nodes to manage. Deploying an Elasticsearch domain with at least three dedicated primary nodes ensures sufficient primary node resource capacity and cluster operations if a node fails.

Remediation

To modify the number of dedicated primary nodes in an OpenSearch domain
  1. Open the Amazon OpenSearch Service console at https://console.aws.amazon.com/aos/.

  2. Under Domains, choose the name of the domain you want to edit.

  3. Choose Edit domain.

  4. Under Dedicated master nodes, set Instance type to the desired instance type.

  5. Set Number of master nodes equal to three or greater.

  6. Choose Submit.

[ES.8] Connections to Elasticsearch domains should be encrypted using the latest TLS security policy

Related requirements: NIST.800-53.r5 AC-17(2), NIST.800-53.r5 AC-4, NIST.800-53.r5 IA-5(1), NIST.800-53.r5 SC-12(3), NIST.800-53.r5 SC-13, NIST.800-53.r5 SC-23, NIST.800-53.r5 SC-23(3), NIST.800-53.r5 SC-7(4), NIST.800-53.r5 SC-8, NIST.800-53.r5 SC-8(1), NIST.800-53.r5 SC-8(2), NIST.800-53.r5 SI-7(6)

Category: Protect > Data protection > Encryption of data in transit

Severity: Medium

Resource type: AWS::Elasticsearch::Domain

AWS Config rule: elasticsearch-https-required (custom Security Hub rule)

Schedule type: Change triggered

Parameters: None

This controls checks whether an Elasticsearch domain endpoint is configured to use the latest TLS security policy. The control fails if the Elasticsearch domain endpoint isn't configured to use the latest supported policy or if HTTPs isn't enabled. The current latest supported TLS security policy is Policy-Min-TLS-1-2-PFS-2023-10.

HTTPS (TLS) can be used to help prevent potential attackers from using person-in-the-middle or similar attacks to eavesdrop on or manipulate network traffic. Only encrypted connections over HTTPS (TLS) should be allowed. Encrypting data in transit can affect performance. You should test your application with this feature to understand the performance profile and the impact of TLS. TLS 1.2 provides several security enhancements over previous versions of TLS.

Remediation

To enable TLS encryption, use the UpdateDomainConfig API operation to configure the DomainEndpointOptions object. This sets the TLSSecurityPolicy.