Securing HTTP client applications

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

HTTP/REST clients and security

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>

The <TOKEN> is computed as base64(USERNAME:PASSWORD)

Alternatively, you can use token-based authentication services.

Client examples

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>

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>

The <TOKEN> is computed as base64(API key ID:API key)

Client libraries over HTTP

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