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Teleport Role-based access request
Teleport Role-based access request

Length: 01:17

Version: 15.x

Dual Authorization

You can set up Teleport to require the approval of multiple team members to perform some critical actions. Here are the most common scenarios:

  • Improve the security of your system and prevent one successful phishing attack from compromising your system.
  • Satisfy FedRAMP AC-3 Dual authorization control that requires approval of two authorized individuals.

In this guide, we will set up Teleport's Just-in-Time Access Requests to require the approval of two team members for a privileged role dbadmin.

The steps below describe how to use Teleport with Mattermost. You can also integrate with many other providers.

warning

Dual Authorization requires Teleport Enterprise.

Prerequisites​

  • Mattermost installed.
Running Mattermost locally with Docker
$ docker run --name mattermost-preview -d --publish 8065:8065 --add-host dockerhost:127.0.0.1 mattermost/mattermost-preview
  • To check that you can connect to your Teleport cluster, sign in with tsh login, then verify that you can run tctl commands using your current credentials. tctl is supported on macOS and Linux machines. For example: 
    $ tsh login --proxy=teleport.example.com [email protected]
    $ tctl status
    # Cluster  teleport.example.com
    # Version  15.4.22
    # CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678
    If you can connect to the cluster and run the tctl status command, you can use your current credentials to run subsequent tctl commands from your workstation. If you host your own Teleport cluster, you can also run tctl commands on the computer that hosts the Teleport Auth Service for full permissions.

Step 1/2. Set up a Teleport bot​

Create a bot within Mattermost​

Enable bot account creation in "System Console -> Integrations".

Toggle Enable Bot Account Creation.

Enable bots

Go back to your team settings, navigate to "Integrations -> Bot Accounts". Press "Add Bot Account".

Enable bots

Add the "Post All" permission on the new account.

Enable bots

Create the bot and save the access token.

Set up RBAC for the plugin​

Teleport's Access Request plugins authenticate to your Teleport cluster as a user with permissions to list and read Access Requests. This way, plugins can retrieve Access Requests from the Teleport Auth Service and present them to reviewers.

Define a user and role called access-plugin by adding the following content to a file called access-plugin.yaml:

kind: role
version: v5
metadata:
  name: access-plugin
spec:
  allow:
    rules:
      - resources: ['access_request']
        verbs: ['list', 'read']
      - resources: ['access_plugin_data']
        verbs: ['update']
---
kind: user
metadata:
  name: access-plugin
spec:
  roles: ['access-plugin']
version: v2

Create the user and role:

$ tctl create -f access-plugin.yaml

As with all Teleport users, the Teleport Auth Service authenticates the access-plugin user by issuing short-lived TLS credentials. In this case, we will need to request the credentials manually by impersonating the access-plugin role and user.

If you are running a self-hosted Teleport Enterprise deployment and are using tctl from the Auth Service host, you will already have impersonation privileges.

To grant your user impersonation privileges for access-plugin, define a role called access-plugin-impersonator by pasting the following YAML document into a file called access-plugin-impersonator.yaml:

kind: role
version: v5
metadata:
  name: access-plugin-impersonator
spec:
  allow:
    impersonate:
      roles:
      - access-plugin
      users:
      - access-plugin

Create the access-plugin-impersonator role:

$ tctl create -f access-plugin-impersonator.yaml

If you are providing identity files to the plugin with Machine ID, assign the access-plugin role to the Machine ID bot user. Otherwise, assign this role to the user you plan to use to generate credentials for the access-plugin role and user:

Assign the access-plugin-impersonator role to your Teleport user by running the appropriate commands for your authentication provider:

  1. Retrieve your local user's roles as a comma-separated list:

    $ ROLES=$(tsh status -f json | jq -r '.active.roles | join(",")')

  2. Edit your local user to add the new role:

    $ tctl users update $(tsh status -f json | jq -r '.active.username') \
      --set-roles "${ROLES?},access-plugin-impersonator"

  3. Sign out of the Teleport cluster and sign in again to assume the new role.

You will now be able to generate signed certificates for the access-plugin role and user.

Export the access-plugin identity files​

Like all Teleport users, access-plugin needs signed credentials in order to connect to your Teleport cluster. You will use the tctl auth sign command to request these credentials.

The following tctl auth sign command impersonates the access-plugin user, generates signed credentials, and writes an identity file to the local directory:

$ tctl auth sign --user=access-plugin --out=identity

The plugin connects to the Teleport Auth Service's gRPC endpoint over TLS.

The identity file, identity, includes both TLS and SSH credentials. The plugin uses the SSH credentials to connect to the Proxy Service, which establishes a reverse tunnel connection to the Auth Service. The plugin uses this reverse tunnel, along with your TLS credentials, to connect to the Auth Service's gRPC endpoint.

Certificate Lifetime

By default, tctl auth sign produces certificates with a relatively short lifetime. For production deployments, we suggest using Machine ID to programmatically issue and renew certificates for your plugin. See our Machine ID getting started guide to learn more.

Note that you cannot issue certificates that are valid longer than your existing credentials. For example, to issue certificates with a 1000-hour TTL, you must be logged in with a session that is valid for at least 1000 hours. This means your user must have a role allowing a max_session_ttl of at least 1000 hours (60000 minutes), and you must specify a --ttl when logging in:

$ tsh login --proxy=teleport.example.com --ttl=60060

If you are running the plugin on a Linux server, create a data directory to hold certificate files for the plugin:

$ sudo mkdir -p /var/lib/teleport/api-credentials
$ sudo mv identity /var/lib/teleport/plugins/api-credentials

If you are running the plugin on Kubernetes, Create a Kubernetes secret that contains the Teleport identity file:

$ kubectl -n teleport create secret generic --from-file=identity plugin-identity

Once the Teleport credentials expire, you will need to renew them by running the tctl auth sign command again.

We'll reference the exported file(s) later when configuring the plugin.

Install the plugin​

$ curl -L https://get.gravitational.com/teleport-access-mattermost-v15.4.22-linux-amd64-bin.tar.gz
$ tar -xzf teleport-access-mattermost-v15.4.22-linux-amd64-bin.tar.gz
$ cd teleport-access-mattermost
$ ./install
$ teleport-mattermost configure > /etc/teleport-mattermost.toml

Update the config with the Teleport address, Mattermost URL, and a bot token:

# example mattermost configuration TOML file
[teleport]
auth_server = "myinstance.teleport.sh:443"                   # Teleport Cloud proxy HTTPS address
identity = "/var/lib/teleport/plugins/mattermost/identity"   # Identity file path
refresh_identity = true                                      # Refresh identity file on a periodic basis.

[mattermost]
url = "https://mattermost.example.com" # Mattermost Server URL
team = "team-name"                     # Mattermost team in which the channel resides.
channel = "channel-name"               # Mattermost Channel name to post requests to
token = "api-token"                    # Mattermost Bot OAuth token
secret = "signing-secret-value"        # Mattermost API signing Secret

[http]
public_addr = "example.com" # URL on which callback server is accessible externally, e.g. [https://]teleport-mattermost.example.com
# listen_addr = ":8081" # Network address in format [addr]:port on which callback server listens, e.g. 0.0.0.0:443
https_key_file = "/var/lib/teleport/plugins/mattermost/server.key"  # TLS private key
https_cert_file = "/var/lib/teleport/plugins/mattermost/server.crt" # TLS certificate

[log]
output = "stderr" # Logger output. Could be "stdout", "stderr" or "/var/lib/teleport/mattermost.log"
severity = "INFO" # Logger severity. Could be "INFO", "ERROR", "DEBUG" or "WARN".

Step 2/2. Configure dual authorization​

In this section, we will use an example to show you how to require dual authorization for a user to assume a role.

Require dual authorization for a role​

Alice and Ivan are reviewers. They can approve requests for assuming role dbadmin. Bob is a DevOps engineer and can assume the dbadmin role if two members of the reviewer role approve the request.

Create the following dbadmin, dbreviewer and devops roles:

kind: role
version: v5
metadata:
  name: dbreviewer
spec:
  allow:
    review_requests:
      roles: ['dbadmin']
---
kind: role
version: v5
metadata:
  name: devops
spec:
  allow:
    request:
      roles: ['dbadmin']
      thresholds:
        - approve: 2
          deny: 1
---
kind: role
version: v5
metadata:
  name: dbadmin
spec:
  allow:
    logins: ['root']
    node_labels:
      'env': 'prod'
      'type': 'db'

The commands below create the local users Bob, Alice, and Ivan.

$ tctl users add [email protected] --roles=devops
$ tctl users add [email protected] --roles=dbreviewer
$ tctl users add [email protected] --roles=dbreviewer

Create an Access Request​

Bob does not have a role dbadmin assigned to him, but can create an Access Request for it.

Bob can create an Access Request for the dbadmin role in the Web UI or CLI:

Mattermost-Request

Chatbot will notify both Alice and Ivan:

Mattermost-Request

Alice and Ivan can review and approve request using Web UI or CLI:

Teleport-Approve

If Bob has created a request using CLI, he will assume it once it has been approved. Bob can also assume granted Access Request roles using Web UI:

Teleport Assume

Troubleshooting​

Certificate errors in self-hosted deployments​

You may be getting certificate errors if Teleport's Auth Service is missing an address in the server certificate:

authentication handshake failed: x509: cannot validate certificate for 127.0.0.1 because it doesn't contain any IP SANs
x509: certificate is valid for,*.teleport.cluster.local, teleport.cluster.local, not example.com

To fix the problem, update the Auth Service with a public address, and restart Teleport:

auth_service:
  public_addr: ['localhost:3025', 'example.com:3025']