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Teleport

Microsoft SQL Server access with PKINIT authentication (Preview)

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Preview

Microsoft SQL Server access is currently in Preview mode.

This guide will help you to:

  • Install and configure Teleport.
  • Set up access to SQL Server using Active Directory PKINIT authentication.
  • Connect to SQL Server through Teleport.

This guide will focus on SQL Servers using self-hosted Active Directory authentication.

Prerequisites

  • A running Teleport cluster. For details on how to set this up, see one of our Getting Started guides.

  • The tctl admin tool and tsh client tool version >= 13.0.3.

    tctl version

    Teleport v13.0.3 go1.20

    tsh version

    Teleport v13.0.3 go1.20

    See Installation for details.

  • A running Teleport Enterprise cluster. For details on how to set this up, see our Enterprise Getting Started guide.

  • The Enterprise tctl admin tool and tsh client tool version >= 13.0.3, which you can download by visiting your Teleport account.

    tctl version

    Teleport Enterprise v13.0.3 go1.20

    tsh version

    Teleport v13.0.3 go1.20

Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.
  • A SQL Server database with Active Directory authentication enabled.

  • A SQL Server network listener configured with a certificate using Subject Alternative Names.

  • A Windows machine joined to the same Active Directory domain as the database.

  • A Linux node with network access to an Active Directory installation and kinit command with PKINIT extensions installed:

    sudo apt-get update
    sudo apt-get -y install krb5-user krb5-pkinit
    sudo yum -y update
    sudo yum -y install krb5-workstation krb5-pkinit
  • Make sure you can connect to Teleport. Log in to your cluster using tsh, then use tctl remotely:

    tsh login --proxy=teleport.example.com [email protected]
    tctl status

    Cluster teleport.example.com

    Version 13.0.3

    CA pin sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

    You can run subsequent tctl commands in this guide on your local machine.

    For full privileges, you can also run tctl commands on your Auth Service host.

Step 1/7. Create a Teleport user

Tip

To modify an existing user to provide access to the Database Service, see Database Access Access Controls

Create a local Teleport user with the built-in access role:

tctl users add \ --roles=access \ --db-users=\* \ --db-names=\* \ alice
FlagDescription
--rolesList of roles to assign to the user. The builtin access role allows them to connect to any database server registered with Teleport.
--db-usersList of database usernames the user will be allowed to use when connecting to the databases. A wildcard allows any user.
--db-namesList of logical databases (aka schemas) the user will be allowed to connect to within a database server. A wildcard allows any database.
Warning

Database names are only enforced for PostgreSQL and MongoDB databases.

For more detailed information about database access controls and how to restrict access see RBAC documentation.

Step 2/7. Configure a GPO to allow Teleport connections

We need to configure a GPO to allow Teleport database sessions. This includes telling your computers to trust Teleport's CA and allowing certificate-based smart card authentication.

Export Teleport CA and CRL

Database CA Rotation

You will need to repeat these steps if you rotate Teleport's database certificate authority.

  1. Get the Teleport database CA certificate by running:

    tctl auth export --type=db-der > db-ca.cer
  2. Get the Teleport database CRL by running:

    tctl auth crl --type=db > db-ca.crl
  3. Transfer the db-ca.cer and db-ca.crl files to a Windows machine where you can manage your group policy.

Create a GPO and import the Teleport CA

Domain Wide Policy

For the purposes of this guide, we apply the GPO we are about to create to our entire AD domain. In the case where you wish for only a subset of computers within your AD domain to be accessible via Teleport, you should apply the GPO to an OU that includes only these computers.

  1. Create a GPO named Teleport DB Access.

    $GPOName="Teleport DB Access"
    New-GPO -Name $GPOName | New-GPLink -Target $((Get-ADDomain).DistinguishedName)
    
  2. Open the Group Policy Management program, and on the left pane, navigate to $FOREST > Domains > $DOMAIN > Group Policy Objects.

  3. Right click on the GPO you just made (Teleport DB Access), and select Edit....

  4. In the group policy editor, select:

    Computer Configuration > Policies > Windows Settings > Security Settings > Public Key Policies
    
  5. Right click on Trusted Root Certification Authorities and select Import.

  6. Click through the wizard, selecting your CA file (db-ca.cer).

Import Teleport CA
Import Teleport CA

Enable smart card service

Teleport performs certificate-based authentication by emulating a smart card.

  1. Still editing your Teleport DB Access, select:

    Computer Configuration > Policies > Windows Settings > Security Settings > System Services
    
  2. Double click on Smart Card, select Define this policy setting and switch to Automatic then click OK.

Enable Smartcard
Enable the Smart Card service
gpupdate.exe

You will be modifying GPOs, and sometimes GPO modifications can take some time to propagate to all hosts. You can force your changes to take effect immediately on your current host at any time by opening a PowerShell prompt and running gpupdate.exe /force (though the effects of your changes may still take time to propagate to other machines on the domain).

Publish the Teleport CA

This step enables the domain controllers to trust the Teleport CA, which will allow smart card logins via Teleport to succeed.

On a machine that is joined to your domain and logged in as an account in the Domain Administrators group, run the two commands below at a PowerShell prompt to publish the Teleport CA to your Active Directory domain (using the path to the exported Teleport db-ca.cer file that you copied above):

certutil –dspublish –f <PathToCertFile.cer> RootCA
certutil -dspublish -f <PathToCertFile.cert> NTAuthCA

Publish the Teleport CRL

On the same machine, run the command below at a PowerShell prompt to publish the Teleport CRL to your Active Directory domain (using the path to the exported db-ca.crl file that you copied above).

certutil -dspublish -f <PathToCRLFile.crl> TeleportDB
Tip

To avoid waiting until the certificate propagates, you can force the CA retrieval from LDAP after importing the CA and CRL with the command:

certutil -pulse

Step 3/7. Export the LDAP CA certificate

Teleport uses LDAPS to authenticate users, which requires specifying the LDAP CA certificate on the database configuration. To ensure that Teleport trusts the certificate sent by the server during the initial SSL connection, you must export the certificate from your AD. You can export the certificate by running the following PowerShell script on your Windows instance:

$WindowsDERFile = $env:TEMP + "\windows.der"
$WindowsPEMFile = $env:TEMP + "\windows.pem"
certutil "-ca.cert" $WindowsDERFile 
certutil -encode $WindowsDERFile $WindowsPEMFile

$CA_CERT_PEM = Get-Content -Path $WindowsPEMFile
Write-Output $CA_CERT_PEM

Remove-Item $WindowsDERFile -Recurse
Remove-Item $WindowsPEMFile -Recurse

The script will write the LDAP CA contents in PEM format to the terminal, and from there, you can copy and use it on your database configuration.

Step 4/7. Set up the Teleport Database Service

The Database Service requires a valid auth token to connect to the cluster. Generate one by running the following command against your Teleport Auth Service and save it in /tmp/token on the node that will run the Database Service:

tctl tokens add --type=db

Install Teleport on the host where you will run the Teleport Database Service:

Use the appropriate commands for your environment to install your package.

Teleport Edition

Download Teleport's PGP public key

sudo curl https://apt.releases.teleport.dev/gpg \-o /usr/share/keyrings/teleport-archive-keyring.asc

Source variables about OS version

source /etc/os-release

Add the Teleport APT repository for v13. You'll need to update this

file for each major release of Teleport.

echo "deb [signed-by=/usr/share/keyrings/teleport-archive-keyring.asc] \https://apt.releases.teleport.dev/${ID?} ${VERSION_CODENAME?} stable/v13" \| sudo tee /etc/apt/sources.list.d/teleport.list > /dev/null

sudo apt-get update
sudo apt-get install teleport

Source variables about OS version

source /etc/os-release

Add the Teleport YUM repository for v13. You'll need to update this

file for each major release of Teleport.

sudo yum-config-manager --add-repo "$(rpm --eval "https://yum.releases.teleport.dev/$ID/$VERSION_ID/Teleport/%{_arch}/stable/v13/teleport.repo")"
sudo yum install teleport

Tip: Add /usr/local/bin to path used by sudo (so 'sudo tctl users add' will work as per the docs)

echo "Defaults secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin" > /etc/sudoers.d/secure_path

Source variables about OS version

source /etc/os-release

Add the Teleport YUM repository for v13. You'll need to update this

file for each major release of Teleport.

Use the dnf config manager plugin to add the teleport RPM repo

sudo dnf config-manager --add-repo "$(rpm --eval "https://yum.releases.teleport.dev/$ID/$VERSION_ID/Teleport/%{_arch}/stable/v13/teleport.repo")"

Install teleport

sudo dnf install teleport

Tip: Add /usr/local/bin to path used by sudo (so 'sudo tctl users add' will work as per the docs)

echo "Defaults secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin" > /etc/sudoers.d/secure_path

In the example commands below, update $SYSTEM_ARCH with the appropriate value (amd64, arm64, or arm). All example commands using this variable will update after one is filled out.

curl https://get.gravitational.com/teleport-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz.sha256

<checksum> <filename>

curl -O https://cdn.teleport.dev/teleport-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz
shasum -a 256 teleport-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz

Verify that the checksums match

tar -xvf teleport-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz
cd teleport
sudo ./install

Download Teleport's PGP public key

sudo curl https://apt.releases.teleport.dev/gpg \-o /usr/share/keyrings/teleport-archive-keyring.asc

Source variables about OS version

source /etc/os-release

Add the Teleport APT repository for v13. You'll need to update this

file for each major release of Teleport.

echo "deb [signed-by=/usr/share/keyrings/teleport-archive-keyring.asc] \https://apt.releases.teleport.dev/${ID?} ${VERSION_CODENAME?} stable/v13" \| sudo tee /etc/apt/sources.list.d/teleport.list > /dev/null

sudo apt-get update
sudo apt-get install teleport-ent

For FedRAMP/FIPS-compliant installations, install the teleport-ent-fips package instead:

sudo apt-get install teleport-ent-fips

Source variables about OS version

source /etc/os-release

Add the Teleport YUM repository for v13. You'll need to update this

file for each major release of Teleport.

sudo yum-config-manager --add-repo "$(rpm --eval "https://yum.releases.teleport.dev/$ID/$VERSION_ID/Teleport/%{_arch}/stable/v13/teleport.repo")"
sudo yum install teleport-ent

Tip: Add /usr/local/bin to path used by sudo (so 'sudo tctl users add' will work as per the docs)

echo "Defaults secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin" > /etc/sudoers.d/secure_path

For FedRAMP/FIPS-compliant installations, install the teleport-ent-fips package instead:

sudo yum install teleport-ent-fips

Source variables about OS version

source /etc/os-release

Add the Teleport YUM repository for v13. You'll need to update this

file for each major release of Teleport.

Use the dnf config manager plugin to add the teleport RPM repo

sudo dnf config-manager --add-repo "$(rpm --eval "https://yum.releases.teleport.dev/$ID/$VERSION_ID/Teleport/%{_arch}/stable/v13/teleport.repo")"

Install teleport

sudo dnf install teleport-ent

Tip: Add /usr/local/bin to path used by sudo (so 'sudo tctl users add' will work as per the docs)

echo "Defaults secure_path = /sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin" > /etc/sudoers.d/secure_path

For FedRAMP/FIPS-compliant installations, install the teleport-ent-fips package instead:

sudo dnf install teleport-ent-fips

In the example commands below, update $SYSTEM_ARCH with the appropriate value (amd64, arm64, or arm). All example commands using this variable will update after one is filled out.

curl https://get.gravitational.com/teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz.sha256

<checksum> <filename>

curl -O https://cdn.teleport.dev/teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz
shasum -a 256 teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz

Verify that the checksums match

tar -xvf teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-bin.tar.gz
cd teleport-ent
sudo ./install

For FedRAMP/FIPS-compliant installations of Teleport Enterprise, package URLs will be slightly different:

curl https://get.gravitational.com/teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-fips-bin.tar.gz.sha256

<checksum> <filename>

curl -O https://cdn.teleport.dev/teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-fips-bin.tar.gz
shasum -a 256 teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-fips-bin.tar.gz

Verify that the checksums match

tar -xvf teleport-ent-v13.0.3-linux-$SYSTEM_ARCH-fips-bin.tar.gz
cd teleport-ent
sudo ./install
Cloud is not available for Teleport v.
Please use the latest version of Teleport Enterprise documentation.

Copy the join token to a file on the instance where you will run the Database Service, and then use the following configuration, replacing the fields on the database section below as appropriate:

  • uri: The server address, including the port.
  • domain: The Active Directory domain (Kerberos realm) DNS/Address to which SQL Server is joined.
  • spn: Service Principal Name (SPN) for SQL Server to fetch Kerberos tickets.
  • kdc_host_name: SPN of the domain controller responsible for providing the LDAP CA.
  • ldap_cert: The contents of the LDAP CA previously exported.
version: v3
teleport:
  auth_token: abcd123-insecure-do-not-use-this
  proxy_server: teleport.example.com:443

auth_service:
  enabled: no
ssh_service:
  enabled: no
proxy_service:
  enabled: no

db_service:
  enabled: "yes"
  databases:
    - name: my-sqlserver
      protocol: sqlserver
      uri: SQL-SERVER-INSTANCE.ad.teleport.dev:1433
      ad:
        domain: ad.teleport.dev
        spn: MSSQLSvc/SQL-SERVER-INSTANCE.ad.teleport.dev:1433
        kdc_host_name: DOMAIN-CONTROLLER.ad.teleport.dev
        ldap_cert: |
          -----BEGIN CERTIFICATE-----
          ...
          -----END CERTIFICATE-----
Tip

You can look SPNs up in the Attribute Editor of the Active Directory Users and Computers dialog on your AD-joined Windows machine.

If you don't see the Attribute Editor tab, make sure that the "View > Advanced Features" toggle is enabled.

Step 5/7. Start the Database Service

Start the Database Service:

teleport start --config=/etc/teleport.yaml

Step 6/7. Create SQL Server AD users

Note

You can skip this step if you already have Active Directory logins in your SQL Server.

Connect to your SQL Server as an administrative account (e.g. sa) and create logins that will use Active Directory authentication:

master> CREATE LOGIN [EXAMPLE\alice] FROM WINDOWS WITH DEFAULT_DATABASE = [master], DEFAULT_LANGUAGE = [us_english];

Step 7/7. Connect

Log in to your Teleport cluster. Your SQL Server database should appear in the list of available databases:

tsh login --proxy=teleport.example.com --user=alice
tsh db ls

Name Description Labels

--------- ------------------- -------

sqlserver env=dev

To retrieve credentials for a database and connect to it:

tsh db connect --db-user=teleport sqlserver
Note

When you run the tsh db connect command above, tsh attempts to execute the mssql-cli command-line client, which must be available in the user's PATH. If you do not have mssql-cli available on your system, you can run the following command to start a local proxy server that you can connect to with your SQL Server client:

tsh proxy db --db-user=teleport --tunnel sqlserver

Read the Database Access GUI Clients guide for how to connect your DB GUI client to the local proxy.

To log out of the database and remove credentials:

tsh db logout sqlserver

Troubleshooting

Teleport CA and CRL not imported correctly

When connecting to your database, you get an error Error message: authentication failed and Teleport Database Service logs have the error message Failed to authenticate with KDC: kinit: Client not trusted while getting initial credentials. This happens when the Teleport Database CA is not imported correctly or propagated yet. You can force the propagation by running certutil -pulse and trying to connect to your database.

Invalid KDC hostname

If you’re connecting to your database and receive the error Error message: authentication failed and on Teleport Database Service logs, there is the error entry Failed to authenticate with KDC: Password for [email protected]: \nkinit: Cannot read password while getting initial credentials, which means that the KDC hostname is wrong. You can verify your domain controller’s SPN to see if they’re set correctly and update the value on the field kdc_hostname on your database's configuration.

Teleport cannot verify database CA

If your database has a CA that Teleport doesn’t know about, it will return the following error when connecting to it: Error message: TLS Handshake failed: x509: certificate signed by unknown authority (possibly because of "x509: invalid signature: parent certificate cannot sign this kind of certificate" while trying to verify candidate authority certificate "SSL_Self_Signed_Fallback").

To solve this, you can add the following configuration to your Teleport Database Service instance:

...
db_service:
  databases:
    - name: sqlserver
      protocol: sqlserver
+     tls:
+       # Point it to your Database CA PEM certificate.
+       ca_cert_file: "rdsca.pem"
+       # If your database certificate has an empty CN filed, you must change
+       # the TLS mode to only verify the CA.
+       mode: verify-ca
      ad:
       ...

If you’re unable to acquire the database CA, you can skip TLS verification by providing the configuration tls.mode: "insecure". However, we do not recommend skipping TLS verification in production environments.

Next steps

  • Take a look at the YAML configuration reference.

Further reading