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Securing HTTP client applications

ECH ECK ECE Self-Managed

When connecting client applications to Elasticsearch, use these best practices:

  • Always use HTTPS for all connections
  • Validate server certificates to prevent man-in-the-middle attacks
  • Use API keys or token-based authentication rather than basic auth where possible
  • Implement appropriate connection pooling and retry mechanisms
  • Consider mutual TLS for high-security environments

The Elasticsearch security features work with standard HTTP basic authentication headers to authenticate users. Since Elasticsearch is stateless, this header must be sent with every request:

Authorization: Basic <TOKEN>
  1. The <TOKEN> is computed as base64(USERNAME:PASSWORD)

Alternatively, you can use token-based authentication services.

This example uses curl without basic auth to create an index:

curl -XPUT 'localhost:9200/idx'
		
{
  "error":  "AuthenticationException[Missing authentication token]",
  "status": 401
}

Since no user is associated with the request above, an authentication error is returned. Now we’ll use curl with basic auth to create an index as the rdeniro user:

curl --user rdeniro:taxidriver -XPUT 'localhost:9200/idx'
		
{
  "acknowledged": true
}

Some APIs support secondary authorization headers for situations where you want tasks to run with a different set of credentials. For example, you can send the following header in addition to the basic authentication header:

es-secondary-authorization: Basic <TOKEN>
  1. The <TOKEN> is computed as base64(USERNAME:PASSWORD)

The es-secondary-authorization header has the same syntax as the Authorization header. It therefore also supports the use of token-based authentication services. For example:

es-secondary-authorization: ApiKey <TOKEN>
  1. The <TOKEN> is computed as base64(API key ID:API key)

For more information about using security features with the language specific clients, refer to: