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- Authentication >
- Authentication Mechanisms >
- x.509
x.509¶
MongoDB supports x.509 certificate authentication for client authentication and internal authentication of the members of replica sets and sharded clusters.
x.509 certificate authentication requires a secure TLS/SSL connection.
Note
MongoDB disables support for TLS 1.0 encryption on systems where TLS 1.1+ is available. For more details, see Disable TLS 1.0.
Certificate Authority¶
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.
Client x.509 Certificates¶
To authenticate to servers, clients can use x.509 certificates instead of usernames and passwords.
Client Certificate Requirements¶
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:
Each unique MongoDB user must have a unique certificate.
The
subject
of a client x.509 certificate, which contains the Distinguished Name (DN
), must be different than thesubject
s of member x.509 certificates.Important
If a client x.509 certificate’s subject matches the
O
,OU
, andDC
attributes of the Member x.509 Certificate (ortlsX509ClusterAuthDNOverride
, if set) exactly, the client connection is accepted, full permissions are granted, and a warning message appears in the log.Only cluster member x509 certificates should use the same
O
,OU
, andDC
attribute combinations.New in version 4.2: If the MongoDB deployment has
tlsX509ClusterAuthDNOverride
set, the client x.509 certificate’s subject must not match that value.Warning
If a client x.509 certificate’s subject has the same
O
,OU
, andDC
combination as the Member x.509 Certificate (ortlsX509ClusterAuthDNOverride
if set), the client connection is rejected. Only cluster member x509 certificates should use the sameO
,OU
, andDC
combinations as this grants full permissions.
MongoDB User and $external
Database¶
To authenticate with a client certificate, you must first add the value
of the subject
from the client certificate as a MongoDB user. 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.
Add the user in the $external
database; i.e. the
Authentication Database is the $external
database
Changed in version 3.6.3: To use sessions with $external
authentication users (i.e.
Kerberos, LDAP, x.509 users), the usernames cannot be greater
than 10k bytes.
Authenticate¶
To connect and authenticate using x.509 client certificate:
- For MongoDB 4.2 or greater, include the following options for the client:
--tls
(or the deprecated--ssl
option)--tlsCertificateKeyFile
(or the deprecated--sslPEMKeyFile
option)--tlsCertificateKeyFilePassword
(or the deprecated--sslPEMKeyPassword
option) if the certificate key file is encrypted--authenticationDatabase '$external'
--authenticationMechanism MONGODB-X509
- For MongoDB 4.0 and earlier, include the following options for the client:
--ssl
--sslPEMKeyFile
--sslPEMKeyPassword
option if the--sslPEMKeyFile
is encrypted.--authenticationDatabase '$external'
--authenticationMechanism MONGODB-X509
You can also make the TLS/SSL connection first, and then use
db.auth()
in the $external
database to authenticate.
For examples of both cases, see the Authenticate with a x.509 Certificate (Using tls Options) section in Use x.509 Certificates to Authenticate Clients
TLS Connection X509 Certificate Startup Warning¶
Starting in MongoDB 4.2.15, mongod
and mongos
now
issue a startup warning when their certificates do not include a
Subject Alternative Name attribute.
The following platforms do not support common name validation:
- iOS 13 and higher
- MacOS 10.15 and higher
- Go 1.15 and higher
Clients using these platforms will not authenticate to MongoDB servers which use X.509 certificate whose hostnames are specified by CommonName attributes.
Member x.509 Certificates¶
For internal authentication, members of sharded clusters and replica sets can use x.509 certificates instead of keyfiles, which use the SCRAM authentication mechanism.
Member Certificate Requirements¶
The member certificate (net.tls.clusterFile
, if
specified, and net.tls.certificateKeyFile
), used to
verify membership to the sharded cluster or a replica set, must have
the following properties:
A single Certificate Authority (CA) must issue all the x.509 certificates for the members of a sharded cluster or a replica set.
The Distinguished Name (
DN
), found in the member certificate’ssubject
, must specify a non-empty value for at least one of the following attributes: Organization (O
), the Organizational Unit (OU
) or the Domain Component (DC
).The Organization attributes (
O
’s), the Organizational Unit attributes (OU
’s), and the Domain Components (DC
’s) must match those from both thenet.tls.clusterFile
andnet.tls.certificateKeyFile
certificates for the other cluster members (or thetlsX509ClusterAuthDNOverride
value, if set).To match, the certificate must match all specifications of these attributes, or even the non-specification of these attributes. The order of the attributes does not matter.
In the following example, the two
DN
’s contain matching specifications forO
,OU
as well as the non-specification of theDC
attribute.However, the following two
DN
’s contain a mismatch for theOU
attribute since one contains twoOU
specifications and the other, only one specification.Either the Common Name (
CN
) or one of the Subject Alternative Name (SAN
) entries must match the server hostname for other cluster members. Starting in MongoDB 4.2, when comparingSAN
s, MongoDB can compare either DNS names or IP addresses. In previous versions, MongoDB only compares DNS names.For example, the certificates for a cluster could have the following subjects:
If the certificate includes the Extended Key Usage (
extendedKeyUsage
) setting, the value must includeclientAuth
(“TLS Web Client Authentication”).You can also use a certificate that does not include the Extended Key Usage (EKU).
MongoDB Configuration for Membership Authentication¶
In addition to any TLS/SSL configurations as appropriate for your
deployment, include the following to specify x.509 for internal
authentication for each member of your replica set (i.e. the
mongod
instances) or sharded cluster (i.e. the
mongod
and mongos
instances):
security.clusterAuthMode
or--clusterAuthMode
set tox509
net.tls.clusterFile
or--tlsClusterFile
(both new in MongoDB 4.2)
However, if no cluster file is specified, members can use their
certificate key file specified in
net.tls.certificateKeyFile
or
--tlsCertificateKeyFile
(both new in MongoDB 4.2) for membership authentication. This
certificate key file
is used
by mongod
(and mongos
) instances to prove their identity
to clients, but can also be used for membership authentication. To
use for both client authentication and membership authentication,
the certificate must either:
- Omit
extendedKeyUsage
or - Specify
extendedKeyUsage
values
Note
Athough still available, net.ssl.clusterFile
(and the
correponding --sslClusterFile
) and net.ssl.PEMKeyFile
(and the
corresponding --sslPEMKeyFile
)
are deprecated as of MongoDB 4.2.
For deployments using MongoDB version 4.0 and earlier, use
net.ssl.clusterFile
(or the corresponding
--sslClusterFile
) and
net.ssl.PEMKeyFile
(or the corresponding
--sslPEMKeyFile
).
Next Steps¶
For an example of x.509 internal authentication, see Use x.509 Certificate for Membership Authentication.