Enforce Device Trust

Resources protected by the device mode "required" will enforce the use of a trusted device, in addition to establishing the user's identity and enforcing the necessary roles. Furthermore, users using a trusted device leave audit trails that include the device's information.

Device Trust enforcement can be configured with the following three modes of operation, represented by the device_trust_mode authentication setting:

• off - disables device trust. Device authentication is not performed and device-aware audit logs are absent.
• optional - enables device authentication and device-aware audit, but does not require a trusted device to access resources.
• required - enables device authentication and device-aware audit. Additionally, it requires a trusted device for all SSH, Database and Kubernetes connections.

Prerequisites

• A running Teleport cluster. If you want to get started with Teleport, sign up for a free trial.

• The tctl admin tool and tsh client tool version >= 16.0.1.

  Visit Installation for instructions on downloading tctl and tsh.

• To enroll a macOS device, you need:
  • A signed and notarized tsh binary, v12.0.0 or newer. Download the macOS tsh installer.
• To enroll a Windows device, you need:
  • A device with TPM 2.0.
  • A user with administrator privileges. This is only required during enrollment.
  • tsh v13.1.2 or newer. Download the Windows tsh installer.
• To enroll a Linux device, you need:
  • A device with TPM 2.0.
  • A user with permissions to use the /dev/tpmrm0 device (typically done by assigning the tss group to the user).
  • tsh v15.0.0 or newer. Install tsh for Linux.
• To authenticate a Web UI session you need Teleport Connect

Role-based trusted device enforcement

Role-based configuration enforces trusted device access at the role level. It can be configured with the spec.options.device_trust_mode option and applies to the resources in its allow rules. It works similarly to require_session_mfa.

The role below exemplifies trusted device enforcement for DB, K8s and SSH. Alternatively, you may set options.device_trust_mode=required on an existing role for similar effects.

kind: role
version: v7
metadata:
  name: require-trusted-device
spec:
  options:
    device_trust_mode: "required"
  allow:
    db_labels:
      '*': '*'
    db_names:
    - '*'
    db_users:
    - '*'
    kubernetes_groups:
    - '{{internal.kubernetes_groups}}'
    - system:masters
    - developers
    - viewers
    kubernetes_labels:
      '*': '*'
    logins:
    - '{{internal.logins}}'
    node_labels:
      '*': '*'

Update the role:

tctl create -f device-enforcement.yaml

Cluster-wide trusted device enforcement

Cluster-wide configuration enforces trusted device access at the cluster level. Enterprise clusters run in optional mode by default. Changing the mode to required will enforce a trusted device for all SSH, Database and Kubernetes accesses.

To enable device mode required update your configuration as follows:

kind: cluster_auth_preference
version: v2
metadata:
  name: cluster-auth-preference
spec:
  type: local
  second_factor: "on"
  webauthn:
    rp_id: teleport.example.com
  device_trust:
+   mode: "required" # add this line

tctl create -f cap.yaml
cluster auth preference has been updated

tctl edit cluster_auth_preference

auth_service:
  authentication:
    type: local
    second_factor: "on"
    webauthn:
      rp_id: teleport.example.com
    device_trust:
+     mode: "required" # add this line

Once the config is updated, SSH, Database and Kubernetes access without a trusted device will be forbidden. For example, SSH access without a trusted device fails with the following error:

tsh ssh ip-172-31-35-170
ERROR: ssh: rejected: administratively prohibited (unauthorized device)

App Access support

The Teleport App Service may enforce device trust via role-based enforcement.

To access apps protected by device trust using the Web UI (Teleport v16 or later), make sure your device is registered and enrolled, install Teleport Connect, and follow the instructions during login.

Alternatively, you may use tsh proxy app or the certificates issued by tsh app login.

As an example, to enforce device trust for all env:production apps, save the role below as require-trusted-device-apps.yaml:

kind: role
version: v7
metadata:
  name: require-trusted-device-apps
spec:
  options:
    device_trust_mode: "required"
  allow:
    app_labels:
      env: production

Create the role and assign it to a user:

tctl create require-trusted-device-apps.yaml
tctl edit users/alice

kind: user
metadata:
  name: alice
  # (...)
spec:
  roles:
  - access
  - editor
+ - require-trusted-device-apps
  # (...)
version: v2

Now the alice user can only access env:production apps using a trusted device.

Desktop Access support

The Teleport Desktop Service may enforce device trust via role-based enforcement.

To access desktops protected by device trust make sure your device is registered and enrolled, install Teleport Connect, and follow the instructions during login.

As an example, to enforce device trust for all env:production desktops, save the role below as require-trusted-device-desktops.yaml:

kind: role
version: v7
metadata:
  name: require-trusted-device-desktops
spec:
  options:
    device_trust_mode: "required"
  allow:
    windows_desktop_labels:
      env: "production"
    windows_desktop_logins: ["Administrator", "alice"]

Create the role and assign it to a user:

tctl create require-trusted-device-desktops.yaml
tctl edit users/alice

kind: user
metadata:
  name: alice
  # (...)
spec:
  roles:
  - access
  - editor
+ - require-trusted-device-desktops
  # (...)
version: v2

Now the alice user can only access env:production desktops using a trusted device.

Locking a device

Similar to session and identity locking, a device can be locked using tctl lock.

Locking blocks certificate issuance and ongoing or future accesses originating from a locked device. Locking a device only works if device trust is enabled and if the device is enrolled to Teleport.

Find a device ID to lock:

tctl devices ls
Asset Tag     OS    Enroll Status   Device ID------------ -----  ------------- ------------------------------------C00AA0AAAA0A  macOS  enrolled     9cdfc0ad-64b7-4d9c-this-is-an-example

Lock a device:

tctl lock --device=9cdfc0ad-64b7-4d9c-this-is-an-example --ttl=12h
Created a lock with name "5444970a-39a0-4814-968d-e58b4a8fa686".

Now, if a user on that device tries to access an SSH server for example, Teleport will deny access:

tsh ssh ip-172-31-35-170
ERROR: ssh: rejected: administratively prohibited (lock targeting Device:"9cdfc0ad-64b7-4d9c-this-is-an-example" is in force)

Troubleshooting

"binary missing signature or entitlements" on tsh device enroll

A signed and notarized tsh binary is necessary to enroll and use a a trusted device. Download the macOS tsh installer to fix the problem.

"unauthorized device" errors using a trusted device

A trusted device needs to be registered and enrolled before it is recognized by Teleport as such. Follow the registration and enrollment steps and make sure to tsh logout and tsh login after enrollment is done.

"Failed to open the TPM device" on Linux

Linux users need permissions to read and write from the TPM device, /dev/tpmrm0. Without such permissions tsh would need sudo prompts for most operations.

The simplest way to solve this is to check if your distro ships with the tss group and assign it to your OS user. If that is not possible, or you are looking for a different solution, we recommend creating udev rules similar to the ones shipped by the TPM2 Software Stack.

App access and "access to this app requires a trusted device"

Follow the instructions in the Web UI troubleshooting section below (Teleport v16 or later).

Alternatively, you may use one of the tsh commands described by App Access support. For example, for an app called myapp, run tsh proxy app myapp -p 8888, then open http://localhost:8888 in your browser.

If you are already running tsh proxy app, or using the certificates acquired from tsh app login, then it's likely your device isn't registered or enrolled. In this case, follow the advice from the unauthorized device section above.

Desktop access and "access to this app requires a trusted device"

Follow the instructions in the Web UI troubleshooting section below.

Web UI fails to authenticate trusted device

The Web UI attempts to authenticate your device using Teleport Connect during login. If you are not asked to authenticate your device immediately after login, follow the steps below:

1. Make sure your device is registered and enrolled
2. Install Teleport Connect. Use the DEB or RPM packages on Linux (the tarball doesn't register the custom URL handler).
3. Make sure Teleport Connect can access the same resource you are trying to access on the Web
4. Ask your cluster administrator if device trust is enabled (cluster mode "optional" or higher)

If all of the above steps are done, try logging out from the Web UI and logging in again.

Next steps

• Device Management
• Jamf Pro Integration