Protect Azure CLIs with Teleport Application Access

You can use Teleport Application Access to manage access to CLI tools that interact with Azure's APIs. This lets you control access to your infrastructure's management APIs using the same RBAC system that you use to protect your infrastructure itself.

The Teleport Application Service uses Azure managed identities to obtain authentication tokens from Azure. When a user authenticates to Teleport, they can assume one of these managed identities to execute Azure CLI commands.

You can configure which Teleport users or roles have access to specific Azure identities, giving you control over who can obtain credentials for different levels of access to Azure CLIs.

The Teleport Application Service connects to the Teleport Proxy Service over a reverse tunnel, so you can run the Application Service in a private network and prevent unauthorized access to your organization's Azure identities.

Prerequisites

• The az CLI tool installed on your workstation. Teleport's tsh client uses the az binary to execute commands. See the Azure documentation for how to install the az CLI on your operating system.

• An Azure VM where you will run the Teleport Application Service. The Azure VM must be running a Linux distribution.

• The ability to create a user-assigned Azure managed identity and attach it to your VM. Azure requires three role assignments in your Azure account in order to do this: Managed Identity Contributor, Managed Identity Operator, and Virtual Machine Contributor.

  Using existing identities

  In this guide, we will create a user-assigned managed identity to demonstrate Azure CLI access with Teleport.

  If you have another identity you would like Azure CLI users to assume via Teleport, you can use that instead. In this case, you will not need the Managed Identity Contributor role assignment.

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  12.1.1
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  12.1.2
CA pin   sha256:sha-hash-here

Step 1/4. Grant an identity to your VM

In this step, we will create an Azure managed identity and assign it to your Azure VM. The identity we will create will be called teleport-azure, and will have permissions to view resources in your Azure account.

You can enable Teleport to grant access to Azure CLIs under any Azure identity. If you have another one you intend to use, you can skip the creation of a new identity.

Create an Azure managed identity

Visit the Managed Identities view in Azure Portal.

Click Create.

Under Subscription, Resource group, and Region, choose the ones that your VM belongs to.

In the Name field, enter teleport-azure.

Click Review + create, then Create.

Once creation finishes, click Go to resource. On the page for the new identity, click JSON View. At the top of the right sidebar, you will see a field called Resource ID with a value resembling the following:

/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/my-resource-group/providers/Microsoft.ManagedIdentity/userAssignedIdentities/teleport-azure

Copy the URI of this identity so you can use it later in this guide.

Allow the teleport-azure identity to view resources

Once you create an Azure identity, authorize it to access resources in your account. In this case, we will authorize your new Azure identity to view resources in its resource group.

Enter the name of your Azure resource group in the Azure Portal search box and visit the page for that resource group. On the left navigation sidebar, click the Access control (IAM) tab. In the row of buttons at the top of the Access control (IAM) panel, click Add > Add role assignment.

Within the Add role assignment screen, click Reader, a built-in role with view-only access to resources.

Scroll to the bottom of the screen and click Next.

Within the Members tab, in the Assign access to field, choose Managed identity. Click Select members.

On the right sidebar, find the Managed identity dropdown menu and select User-assigned managed identity. Choose the teleport-azure identity you created earlier.

Click Select, then Review + assign.

Verify that your Role is "Reader", the Scope matches your chosen resource group, and the Members field includes the teleport-azure managed identity you created earlier.

Click Review + assign again.

Attach an identity to your Azure VM

Now that you have created a managed identity and assigned it a role, attach the identity to your Azure VM so the Teleport Application Service can assume the identity in order to proxy Azure CLI traffic.

In the Virtual machines view of Azure Portal, click on the name of the VM you are using to host the Teleport Application Service.

On the right side panel, click the Identity tab, then within the Identity view, click the User assigned tab. Click +Add, then select the teleport-azure identity. Click Add.

Navigate back to Identity tab in the page for your Azure VM. You should see the new identity listed in the User assigned sub-tab:

Step 2/4. Deploy the Teleport Application Service

In this step, you will run the Teleport Application Service on the Azure VM you assigned the teleport-azure identity to.

Get a join token

Establish trust between your Teleport cluster and your new Application Service instance by creating a join token:

tctl nodes add --roles=app
The invite token: abcd123-insecure-do-not-use-this
This token will expire in 30 minutes.
Run this on the new node to join the cluster:
> teleport start \
   --roles=app \
   --token=abcd123-insecure-do-not-use-this \
   --ca-pin=sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678 \
   --auth-server=192.0.2.255:3025
Please note:
  - This invitation token will expire in 30 minutes
  - 192.0.2.255:3025 must be reachable from the new node

On the host where you will install the Teleport Application Service, create a file called /tmp/token that consists only of your token:

echo join-token | sudo tee /tmp/token

Install the Teleport Application Service

Run the following commands on the host where you will install the Teleport Application Service:

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

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 v12. You'll need to update this
file for each major release of Teleport.
Note: if using a fork of Debian or Ubuntu you may need to use '$ID_LIKE'
and the codename your distro was forked from instead of '$ID' and '$VERSION_CODENAME'.
Supported versions are listed here: https://github.com/gravitational/teleport/blob/master/build.assets/tooling/cmd/build-os-package-repos/runners.go#L42-L67
echo "deb [signed-by=/usr/share/keyrings/teleport-archive-keyring.asc] \https://apt.releases.teleport.dev/${ID?} ${VERSION_CODENAME?} stable/v12" \| 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 v12. You'll need to update this
file for each major release of Teleport.
Note: if using a fork of RHEL/CentOS or Amazon Linux you may need to use '$ID_LIKE'
and the codename your distro was forked from instead of '$ID'
Supported versions are listed here: https://github.com/gravitational/teleport/blob/master/build.assets/tooling/cmd/build-os-package-repos/runners.go#L133-L153
sudo yum-config-manager --add-repo $(rpm --eval "https://yum.releases.teleport.dev/$ID/$VERSION_ID/Teleport/%{_arch}/stable/v12/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
Optional:  Use DNF on newer distributions
$ sudo dnf config-manager --add-repo https://rpm.releases.teleport.dev/teleport.repo
$ sudo dnf install teleport

curl https://get.gravitational.com/teleport-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz.sha256
<checksum> <filename>
curl -O https://cdn.teleport.dev/teleport-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz
shasum -a 256 teleport-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz
Verify that the checksums match
tar -xvf teleport-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz
cd teleport
sudo ./install

dpkg -i ~/Downloads/teleport-ent_12.1.1_$SYSTEM-ARCH.deb
Selecting previously unselected package teleport-ent.
(Reading database ... 30810 files and directories currently installed.)
Preparing to unpack teleport-ent_12.1.1_$SYSTEM_ARCH.deb ...
Unpacking teleport-ent 12.1.1 ...
Setting up teleport-ent 12.1.1 ...

rpm -i ~/Downloads/teleport-ent-12.1.1.$SYSTEM-ARCH.rpm
warning: teleport-ent-12.1.1.$SYSTEM-ARCH.rpm: Header V4 RSA/SHA512 Signature, key ID 6282c411: NOKEY

curl https://get.gravitational.com/teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz.sha256
<checksum> <filename>
curl -O https://cdn.teleport.dev/teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz
shasum -a 256 teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz
Verify that the checksums match
tar -xvf teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-bin.tar.gz
cd teleport-ent
sudo ./install

curl https://get.gravitational.com/teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-fips-bin.tar.gz.sha256
<checksum> <filename>
curl -O https://cdn.teleport.dev/teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-fips-bin.tar.gz
shasum -a 256 teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-fips-bin.tar.gz
Verify that the checksums match
tar -xvf teleport-ent-v12.1.1-linux-$SYSTEM-ARCH-fips-bin.tar.gz
cd teleport-ent
sudo ./install

Configure the Teleport Application Service

On the host where you will run the Teleport Application Service, create a file at /etc/teleport.yaml with the following content:

version: v3
teleport:
  join_params:
    token_name: "/tmp/token"
    method: token
  proxy_server: "teleport.example.com:443"
auth_service:
  enabled: off
proxy_service:
  enabled: off
ssh_service:
  enabled: off
app_service:
  enabled: true
  apps:
  - name: azure-cli
    cloud: Azure

Edit /etc/teleport.yaml to replace teleport.example.com:443 with the host and port of your Teleport Proxy Service or Teleport Cloud tenant, e.g., mytenant.teleport.sh:443.

The app_service field configures the Teleport Application Service. Each item within app_service.apps is an application configuration.

In this example, we have enabled Azure CLI access by setting cloud to Azure. With this setting configured, the Application Service will proxy user commands from Azure CLIs by requesting access to Azure's APIs under the user's chosen identity, which works as long as the identity is one of the ones attached to the Application Service host.

Run the Teleport Application Service

On the host where you will run the Teleport Application Service, execute the following command, depending on whether you installed Teleport using a package manager or via a TAR archive:

sudo systemctl start teleport

sudo teleport install systemd --output=/etc/systemd/system/teleport.service;
sudo systemctl enable teleport;
sudo systemctl start teleport;

Step 3/4. Enable your user to access Azure CLIs

The next step is to authorize your Teleport user to assume an Azure identity and execute Azure CLI commands via Teleport. You will protect access to this identity using Teleport's RBAC system, where a user's roles determine which Azure managed identities (if any) they can access.

There are two approaches you can take to authorize users to access Azure identities.

kind: role
version: v5
metadata:
  name: azure-cli-access
spec:
  allow:
    app_labels:
      '*': '*'
    azure_identities:
      - '{{internal.azure_identities}}'

tctl users update teleport-user \--set-azure-identities azure-identity-uri

tctl create -f azure-cli-access.yaml

/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/RESOURCE_GROUP_NAME/providers/Microsoft.ManagedIdentity/userAssignedIdentities/IDENTITY_NAME

kind: role
version: v5
metadata:
  name: azure-cli-access
spec:
  allow:
    app_labels:
      '*': '*'
    azure_identities:
      - '{{external.azure_identities}}'

tctl create -f azure-cli-access.yaml

kind: role
version: v5
metadata:
  name: azure-cli-access
spec:
  allow:
    app_labels:
      '*': '*'
    azure_identities:
      - /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/my-resource-group/providers/Microsoft.ManagedIdentity/userAssignedIdentities/teleport-azure

tctl create -f azure-cli-access.yaml

kind: role
version: v5
metadata:
  name: "no-azure-identities"
spec:
  allow:
    app_labels:
      '*': '*'
  deny:
    azure_identities:
      - '*'

Assign the azure-cli-access role to your Teleport user by running the following commands, depending on whether you authenticate as a local Teleport user or via the github, saml, or oidc authentication connectors:

tctl get users/$(tsh status -f json | jq -r '.active.username') > out.yaml

  roles:
   - access
   - auditor
   - editor
+  - azure-cli-access

tctl create -f out.yaml

tctl get github/github --with-secrets > github.yaml

  teams_to_roles:
    - organization: octocats
      team: admins
      roles:
        - access
+       - azure-cli-access

tctl create -f github.yaml

tctl get --with-secrets saml/mysaml > saml.yaml

  attributes_to_roles:
    - name: "groups"
      value: "my-group"
      roles:
        - access
+       - azure-cli-access

tctl create -f saml.yaml

tctl get oidc/myoidc --with-secrets > oidc.yaml

  claims_to_roles:
    - name: "groups"
      value: "my-group"
      roles:
        - access
+       - azure-cli-access

tctl create -f saml.yaml

Log out of your Teleport cluster and log in again to assume the new role.

Step 4/4. Use Azure CLIs with Teleport

Now that you have authorized your Teleport user to assume the teleport-azure identity, you can use Teleport to authenticate to Azure's APIs and execute commands against it via the az CLI.

List your Azure CLI application

Verify that your Teleport user can see the azure-cli application you registered earlier:

tsh apps ls
Application Description Type Public Address                 Labels
----------- ----------- ---- ------------------------------ -------------------
azure-cli               HTTP azure-cli.teleport.example.com teleport.dev/origin

Log in to use an Azure CLI

Log in to the application, specifying that you would like to assume the teleport-azure identity:

tsh apps login azure-cli --azure-identity teleport-azure

This command validates the value of the --azure-identity flag against the ones the user is authorized to assume. The value of the flag can either be the full URI of the identity (e.g., the URI you copied earlier in this guide) or the name of the identity, e.g., teleport-azure.

A user can omit the --azure-identity flag if they are only authorized to access a single Azure identity, but otherwise an empty --azure-identity will result in an error.

If the command succeeds, you will see information about the user's chosen Azure identity similar to the following:

[
  {
    "environmentName": "AzureCloud",
    "homeTenantId": "00000000-0000-0000-0000-000000000000",
    "id": "00000000-0000-0000-0000-000000000000",
    "isDefault": true,
    "managedByTenants": [],
    "name": "Microsoft Azure Sponsorship",
    "state": "Enabled",
    "tenantId": "00000000-0000-0000-0000-000000000000",
    "user": {
      "assignedIdentityInfo": "MSIResource-/subscriptions/0000000000000-0000-0000-000000000000/resourceGroups/my-resource-group/providers/Microsoft.ManagedIdentity/userAssignedIdentities/teleport-azure",
      "name": "userAssignedIdentity",
      "type": "servicePrincipal"
    }
  }
]

Logged into Azure app "azure-cli".
Your identity: /subscriptions/0000000000000-0000-0000-000000000000/resourceGroups/my-resource-group/providers/Microsoft.ManagedIdentity/userAssignedIdentities/teleport-azure
Example Azure CLI command: tsh az vm list

Execute Azure CLI commands

At this point, you can run az commands using the Teleport Application Service by prefixing them with tsh. To list VMs running in your Azure resource group, for example, run the following command:

tsh az vm list

Use Azure CLI applications without tsh

In addition to running az commands via tsh, you can grant secure access to any CLI application that executes commands against Azure's APIs.

To do this, use tsh to start a local proxy that forwards traffic from your CLI application to the Teleport Application Service. The Application Service uses an Azure managed identity to fetch an authentication token from Azure, which your CLI application uses to authenticate requests to Azure's APIs.

To start the local proxy, run the following tsh command:

tsh proxy azure

The command will print the address of the local proxy server along with export commands for assigning environment variables. Azure CLI applications read these variables in order to request an authentication token for Azure's APIs:

Started Azure proxy on http://127.0.0.1:54330.
To avoid port randomization, you can choose the listening port using the --port flag.

Use the following credentials and HTTPS proxy setting to connect to the proxy:

  export AZURE_CONFIG_DIR=/Users/myuser/.tsh/azure/my.teleport.cluster/azure
  export HTTPS_PROXY=http://127.0.0.1:54330
  export HTTP_PROXY=http://127.0.0.1:54330
  export MSI_ENDPOINT=https://azure-msi.teleport.dev/eedfd5b55257c0aaa58f
  export REQUESTS_CA_BUNDLE=/Users/myuser/.tsh/keys/teleport.example.com/myuser-app/teleport.example.com/azure-cli-localca.pem

Copy the export commands and paste them into a second terminal. In that terminal, you can now run your Azure CLI application of choice. For example, you can run the following command to list Azure VMs:

az vm list

Since the az CLI requests an authentication token using the teleport-azure identity you created earlier, and that identity is authorized to view resources in your resource group, the az vm list command will only list VMs in that resource group.

Next steps

• Now that you know how to protect Azure CLI access using Teleport, ensure that your Teleport users can only manage Azure resources temporarily, with no longstanding admin roles for attackers to hijack. View our documentation on Role Access Requests and Access Request plugins.
• Consult the Azure documentation for information about Azure managed identities and how to manage user-assigned managed identities.
• See the Azure documentation for the full list of az CLI commands.