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Use x.509 Certificates to Authenticate Clients

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  • Prerequisites
  • Procedures
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.

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.

For production use, your MongoDB deployment should use valid certificates generated and signed by a certificate authority. You or your organization can generate and maintain an independent certificate authority, or use certificates generated by third-party TLS/SSL vendors. 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.

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.

    At least one of the Organization (O), Organizational Unit (OU), or Domain Component (DC) attributes in the client certificate must differ from those in the net.tls.clusterFile and net.tls.certificateKeyFile server certificates.

    If the MongoDB deployment has tlsX509ClusterAuthDNOverride set (available starting in MongoDB 4.2), the client x.509 certificate's subject must also differ from that value.

    Warning

    If a client x.509 certificate's subject has the same O, OU, and DC combination as the Member x.509 Certificate (or tlsX509ClusterAuthDNOverride if set), the client connection is rejected. Only cluster member x509 certificates should use same O, OU, and DC combinations as this grants full permissions.

  • The x.509 certificate must not be expired.

    Changed in version 4.4: mongod / mongos logs a warning on connection if the presented x.509 certificate expires within 30 days of the mongod/mongos host system time. See x.509 Certificates Nearing Expiry Trigger Warnings for more information.

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.

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

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.

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

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.

To use Client Sessions and Causal Consistency Guarantees with $external authentication users (Kerberos, LDAP, or 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.

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.

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.

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