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Use x.509 Certificates to Authenticate Clients

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Note

Starting in version 4.0, MongoDB disables support for TLS 1.0 encryption on systems where TLS 1.1+ is available. For more details, see Disable TLS 1.0.

MongoDB supports x.509 certificate authentication for use with a secure TLS/SSL connection. The x.509 client authentication allows clients to authenticate to servers with certificates rather than with a username and password. The following tutorial outlines the steps to use x.509 for client authentication with a standalone mongod instance.

To use x.509 authentication for replica sets or sharded clusters, see Use x.509 Certificate for Membership Authentication.

Prerequisites

Important

A full description of TLS/SSL, PKI (Public Key Infrastructure) certificates, in particular x.509 certificates, and Certificate Authority is beyond the scope of this document. This tutorial assumes prior knowledge of TLS/SSL as well as access to valid x.509 certificates.

Certificate Authority

For production use, your MongoDB deployment should use valid certificates generated and signed by a single certificate authority. You or your organization can generate and maintain an independent certificate authority, or use certificates generated by a third-party TLS/SSL vendor. Obtaining and managing certificates is beyond the scope of this documentation.

Important

To use x.509 authentication, --tlsCAFile or net.tls.CAFile must be specified unless using --tlsCertificateSelector or --net.tls.certificateSelector. Or if using the ssl aliases, --sslCAFile or net.ssl.CAFile must be specified unless using --sslCertificateSelector or net.ssl.certificateSelector.

Client x.509 Certificate

Note

You must have valid x.509 certificates.

Starting in MongoDB 4.0, if you specify --sslAllowInvalidCertificates or net.ssl.allowInvalidCertificates: true (or in MongoDB 4.2, the alias --tlsAllowInvalidateCertificates or net.tls.allowInvalidCertificates: true) when using x.509 authentication, an invalid certificate is only sufficient to establish a TLS/SSL connection but is insufficient for authentication.

The client certificate must have the following properties:

  • A single Certificate Authority (CA) must issue the certificates for both the client and the server.

  • Client certificates must contain the following fields:

    keyUsage = digitalSignature
    extendedKeyUsage = clientAuth
    
  • Each unique MongoDB user must have a unique certificate.

  • A client x.509 certificate’s subject, which contains the Distinguished Name (DN), must differ from that of a Member x.509 Certificate. Specifically, the subjects must differ with regards to at least one of the following attributes: Organization (O), the Organizational Unit (OU) or the Domain Component (DC).

    Warning

    If a client x.509 certificate’s subject has the same O, OU, and DC combination as the Member x.509 Certificate, the client will be identified as a cluster member and granted full permission on the system.

MongoDB Deployment Configured for x.509 (Using TLS Options)

Note

The procedures in this section use the tls settings/option (Available in MongoDB 4.2). For procedures using their ssl aliases, see MongoDB Deployment Configured for x.509 (Using SSL Options).

The tls settings/options provide identical functionality as the ssl options since MongoDB has always supported TLS 1.0 and later.

You can configure a mongod instance for x.509 authentication from the command-line. For example, to configure a standalone mongod instance:

mongod --tlsMode requireTLS --tlsCertificateKeyFile <path to TLS/SSL certificate and key PEM file> --tlsCAFile <path to root CA PEM file> --bind_ip <hostnames>

Include additional options as required for your configuration. For instance, if you wish remote clients to connect to your deployment or your deployment members are run on different hosts, specify the --bind_ip. For more information, see Localhost Binding Compatibility Changes.

The x.509 configuration requires:

Option Notes
--tlsMode Specify requireTLS.
--tlsCertificateKeyFile The instance’s x.509 certificate to present to clients.
--tlsCAFile Certificate Authority file to verify the certificates presented to the instance.

You can configure mongod for x.509 authentication in the configuration file. For example, to configure a standalone mongod instance:

net:
   tls:
      mode: requireTLS
      certificateKeyFile: <path to TLS/SSL certificate and key PEM file>
      CAFile: <path to root CA PEM file>

Include additional options as required for your configuration. For instance, if you wish remote clients to connect to your deployment or your deployment members are run on different hosts, specify the net.bindIp setting. For more information, see Localhost Binding Compatibility Changes.

The x.509 configuration requires:

Option Notes
net.tls.mode Specify requireTLS.
net.tls.certificateKeyFile The instance’s x.509 certificate.
net.tls.CAFile Certificate Authority file to verify the certificates presented to the instance.

To set up x.509 authentication for replica sets or sharded clusters, see Use x.509 Certificate for Membership Authentication.

MongoDB Deployment Configured for x.509 (Using SSL Options)

Note

The procedures in this section use the ssl settings/option. For procedures using their tls aliases (Available in MongoDB 4.2), see MongoDB Deployment Configured for x.509 (Using TLS Options).

The tls settings/options provide identical functionality as the ssl options since MongoDB has always supported TLS 1.0 and later.

You can configure a mongod instance for x.509 authentication from the command-line. For example, to configure a standalone mongod instance:

mongod --sslMode requireSSL --sslPEMKeyFile <path to TLS/SSL certificate and key PEM file> --sslCAFile <path to root CA PEM file>  --bind_ip <hostnames>

Include additional options as required for your configuration. For instance, if you wish remote clients to connect to your deployment or your deployment members are run on different hosts, specify the --bind_ip. For more information, see Localhost Binding Compatibility Changes.

The x.509 configuration for a standalone requires:

Option Notes
--sslMode Specify requireSSL.
--sslPEMKeyFile The instance’s x.509 certificate.
--sslCAFile Certificate Authority file to verify the certificate presented to the instance.

You can configure mongod for x.509 authentication in the configuration file. For example, to configure a standalone mongod instance:

net:
   ssl:
      mode: requireSSL
      PEMKeyFile: <path to TLS/SSL certificate and key PEM file>
      CAFile: <path to root CA PEM file>

Include additional options as required for your configuration. For instance, if you wish remote clients to connect to your deployment or your deployment members are run on different hosts, specify the net.bindIp setting. For more information, see Localhost Binding Compatibility Changes.

The x.509 configuration for a standalone requires:

Option Notes
net.ssl.mode Specify requireSSL.
net.ssl.PEMKeyFile The instance’s x.509 certificate.
net.ssl.CAFile Certificate Authority file to verify the certificate presented to the instance.

To set up x.509 authentication for replica sets or sharded clusters, see Use x.509 Certificate for Membership Authentication.

Procedures

Add x.509 Certificate subject as a User

To authenticate with a client certificate, you must first add the value of the subject from the client certificate as a MongoDB user to the $external database. Each unique x.509 client certificate corresponds to a single MongoDB user; i.e. you cannot use a single client certificate to authenticate more than one MongoDB user.

Changed in version 3.6.3: To use sessions with $external authentication users (i.e. Kerberos, LDAP, x.509 users), the usernames cannot be greater than 10k bytes.

Note

The RDNs in the subject string must be compatible with the RFC2253 standard.

  1. You can retrieve the RFC2253 formatted subject from the client certificate with the following command:

    openssl x509 -in <pathToClientPEM> -inform PEM -subject -nameopt RFC2253
    

    The command returns the subject string as well as certificate:

    subject= CN=myName,OU=myOrgUnit,O=myOrg,L=myLocality,ST=myState,C=myCountry
    -----BEGIN CERTIFICATE-----
    # ...
    -----END CERTIFICATE-----
    
  2. Add the RFC2253 compliant value of the subject as a user. Omit spaces as needed.

    For example, the following adds a user and grants the user readWrite role in the test database and the userAdminAnyDatabase role:

    db.getSiblingDB("$external").runCommand(
      {
        createUser: "CN=myName,OU=myOrgUnit,O=myOrg,L=myLocality,ST=myState,C=myCountry",
        roles: [
             { role: "readWrite", db: "test" },
             { role: "userAdminAnyDatabase", db: "admin" }
        ],
        writeConcern: { w: "majority" , wtimeout: 5000 }
      }
    )
    

See Manage Users and Roles for details on adding a user with roles.

Authenticate with a x.509 Certificate (Using tls Options)

Note

The procedures in this section use the tls settings/option (Available in MongoDB 4.2). For procedures using their ssl aliases, see Authenticate with a x.509 Certificate (Using ssl Options).

The tls settings/options provide identical functionality as the ssl options since MongoDB has always supported TLS 1.0 and later.

After you have added the x.509 client certificate subject as a corresponding MongoDB user, you can authenticate with the client certificate.

To authenticate during connection:

mongo --tls --tlsCertificateKeyFile <path to client PEM file> --tlsCAFile <path to root CA PEM file>  --authenticationDatabase '$external' --authenticationMechanism MONGODB-X509
Option Notes
--tls  
--tlsCertificateKeyFile Client’s x.509 file.
--tlsCAFile Certificate Authority file to verify the certificate presented by the mongod instance.
--authenticationDatabase Specify '$external'.
--authenticationMechanism Specify MONGODB-X509.

You can connect without authentication and use the db.auth() method to authenticate after connection.

For example, if using the mongo shell,

  1. Connect mongo shell to the mongod set up for TLS/SSL:

    mongo --tls --tlsCertificateKeyFile <path to client PEM file> --sslCAFile <path to root CA PEM file>
    
    Option Notes
    --tls  
    --tlsCertificateKeyFile Client’s x.509 file.
    --tlsCAFile Certificate Authority file to verify the certificate presented by mongod/mongos instance.
  2. To perform the authentication, use the db.auth() method in the $external database. For the mechanism field, specify "MONGODB-X509".

    db.getSiblingDB("$external").auth(
      {
        mechanism: "MONGODB-X509"
      }
    )
    

Authenticate with a x.509 Certificate (Using ssl Options)

Note

The procedures in this section use the ssl settings/options. For procedures using their tls (Available in MongoDB 4.2) aliases, see Authenticate with a x.509 Certificate (Using tls Options).

The tls settings/options provide identical functionality as the ssl options since MongoDB has always supported TLS 1.0 and later.

After you have added the x.509 client certificate subject as a corresponding MongoDB user, you can authenticate with the client certificate.

To authenticate during connection:

mongo --ssl --sslPEMKeyFile <path to CA signed client PEM file> --sslCAFile <path to root CA PEM file>  --authenticationDatabase '$external' --authenticationMechanism MONGODB-X509
Option Notes
--ssl  
--sslPEMKeyFile Client’s x.509 file.
--sslCAFile Certificate Authority file to verify the certificate presented by mongod/mongos instance.
--authenticationDatabase Specify '$external'.
--authenticationMechanism Specify MONGODB-X509.

You can connect without authentication and use the db.auth() method to authenticate after connection.

For example, if using the mongo shell,

  1. Connect mongo shell to the mongod set up for TLS/SSL:

    mongo --ssl --sslPEMKeyFile <path to CA signed client PEM file> --sslCAFile <path to root CA PEM file>
    
    Option Notes
    --ssl  
    --sslPEMKeyFile Client’s x.509 file.
    --sslCAFile Certificate Authority file to verify the certificate presented by mongod/mongos instance.
  2. To perform the authentication, use the db.auth() method in the $external database. For the mechanism field, specify "MONGODB-X509".

    db.getSiblingDB("$external").auth(
      {
        mechanism: "MONGODB-X509"
      }
    )