Multi-Factor Authentication

TYPO3 is capable of authentication via multiple factors, in short “multi-factor authentication” or “MFA”. This is sometimes also referred to “2FA” as a 2-Factor Authentication process, where - in order to log in - the user needs

  1. “something you know” (= the password) and
  2. “something you own” (= an authenticator device, or an authenticator app on mobile phones or desktop devices).

Read more about the concepts of MFA here https://en.wikipedia.org/wiki/Multi-factor_authentication

TYPO3 Login Screen for entering MFA code (TOTP)

TYPO3 ships with some built-in MFA providers by default. But more importantly, TYPO3 provides an API to allow extension authors to integrate their own MFA providers.

The API is designed in a way to allow providers to be used for TYPO3 Backend Authentication or Frontend Authentication with a multi-factor step in-between.

Note

TYPO3 Core currently provides the integration for the TYPO3 Backend, but will fully support multi-factor authentication for the Frontend in future releases.

Managing MFA providers is currently possible via the User Settings module in the tab called Account security. The Account security tab displays the current state:

  • whether MFA can be configured
  • whether MFA is activated or
  • whether some MFA providers are locked

Included MFA providers

TYPO3 Core includes two MFA providers:

  1. Time-based one-time password (TOTP)

The most common MFA implementation. A QR-code is scanned (or alternatively, a shared secret can be entered) to connect an Authenticator app such as Google Authenticator, Microsoft Authenticator, 1Password, Authly or others to the system and then synchronize a token, which changes every 30 seconds.

On each log-in, after successfully entering the password, the 6-digit code shown by the Authenticator App must be entered.

  1. Recovery codes

This is a special provider which can only be activated if at least one other provider is active, as it’s only meant as a fallback provider, in case the authentication credentials for the “main” provider(s) are lost. It is encouraged to activate this provider, and keep the codes at a safe place.

Select a MFA provider screen

Setting up MFA for a backend user

Each provider is displayed with its icon, the name and a short description in the MFA configuration module. In case a provider is active this is indicated by a corresponding label, next to the providers’ title. The same goes for a locked provider - an active provider, which can currently not be used since the provider specific implementation detected some unusual behaviour, e.g. to many false authentication attempts. Additionally, the configured default provider indicates this state with a “star” icon, next to the providers’ title.

Each inactive provider contains a Setup button which opens the corresponding configuration view. This view can be different depending on the MFA provider.

MFA TOTP provider configuration screen

Each provider contains an Edit/Change button, which allows to adjust the providers’ settings. This view allows for example to set a provider as the default (primary) provider, to be used on authentication.

Note

The default provider setting will be automatically applied on activation of the first provider or in case it is the recommended provider for this user.

In case the provider is locked, the Edit/Change button changes its button title to Unlock. This button can be used to unlock the provider. This, depending on the provider to unlock, may require further actions by the user.

The “Deactivate” button can be used to deactivate the provider. This will, depending on the provider, usually also completely remove all provider specific settings.

The “Authentication view” is displayed as soon as a user with at least one active provider has successfully passed the username and password mask.

As for the other views, it is up to the specific provider, used for the current multi-factor authentication attempt, what content is displayed in which view. If the user has further active providers, the view displays them as “Alternative providers” in the footer to allow the user to switch between all activated providers on every authentication attempt.

All providers need to define a locking functionality. In case of the TOTP and recovery code providers, this e.g. includes an attempts count. These providers are locked in case a wrong OTP was entered three times in a row. The count is automatically reset as soon as a correct OTP is entered or the user unlocks the provider in the backend.

All TYPO3 core providers also feature the “Last used” and “Last updated” information which can be retrieved in the “Edit/Change” view.

By default, the new field in the User Settings module is displayed for every backend user. It is possible to disable it for specific users via userTSconfig:

setup.fields.mfaProviders.disabled = 1

Administration of users’ MFA providers

If a user is not able to access the backend anymore, e.g. because all of their active providers are locked, MFA needs to be disabled by an administrator for this specific user.

Administrators are able to manage users’ MFA providers in the corresponding user record. The new Multi-factor authentication field displays a list of active providers and a button to deactivate MFA for the user, or only a specific MFA provider.

Note

All of these deactivate buttons are executed immediately, after confirming the dialog, and cannot be undone.

The backend users listing in the backend user module also displays whether MFA is enabled or currently locked, for each user. This allows an administrator to analyze their users’ MFA usage at a glance.

The System => Configuration admin module shows an overview of all currently registered providers in the installation. This is especially helpful to find out the exact provider identifier, needed for some userTSconfig options.

MFA providers in the configuration module

Configuration

Enforcing MFA for users

It seems reasonable to require MFA for specific users or user groups. This can be achieved with $GLOBALS['TYPO3_CONF_VARS']['BE']['requireMFA'] which allows 4 options:

  • 0: Do not require multi-factor authentication (default)
  • 1: Require multi-factor authentication for all users
  • 2: Require multi-factor authentication only for non-admin users
  • 3: Require multi-factor authentication only for admin users

To set this requirement only for a specific user or user group, a new userTSconfig option auth.mfa.required is introduced. The userTSconfig option overrules the global configuration.

auth.mfa.required = 1

Note

Requiring MFA has currently limited effect. Only an information is displayed in the MFA configuration module. This will change in future releases when this setting will require MFA being configured on accessing the TYPO3 Backend the first time. You are still already able to try it out.

Allowed provider

It is possible to only allow a subset of the available providers for some users or user groups.

A configuration option “Allowed multi-factor authentication providers” is available in the user groups record in the “Access List” tab.

There may be use cases in which a single provider should be disallowed for a specific user, which is configured to be allowed in one of the assigned user groups. Therefore, the userTSconfig option auth.mfa.disableProviders can be used. It overrules the configuration from the “Access List”, which means if a provider is allowed in “Access List” but disallowed via userTSconfig, it will be disallowed for the user or user group the TSconfig applies to.

This does not affect the remaining allowed providers from the “Access List”.

auth.mfa.disableProviders := addToList(totp)

TYPO3 Integration and API

Important

The MFA API is still experimental and subject to change until v11 LTS, since we are looking forward to receive feedback, especially for custom use-cases, the API is not capable yet.

To register a custom MFA provider, the provider class has to implement the new MfaProviderInterface, shipped via a third-party extension. The provider then has to be configured in the extensions’ Services.yaml or Services.php file with the mfa.provider tag.

Vender\Extension\Authentication\Mfa\MyProvider:
   tags:
      - name: mfa.provider
        identifier: 'my-provider'
        title: 'LLL:EXT:extension/Resources/Private/Language/locallang.xlf:myProvider.title'
        description: 'LLL:EXT:extension/Resources/Private/Language/locallang.xlf:myProvider.description'
        setupInstructions: 'LLL:EXT:extension/Resources/Private/Language/locallang.xlf:myProvider.setupInstructions'
        icon: 'tx-extension-provider-icon'

This will register the provider MyProvider with the my-provider identifier. To change the position of your provider the before and after arguments can be useful. This can be needed if you e.g. like your provider to show up prior to any other provider in the MFA configuration module. The ordering is also taken into account in the authentication step while logging in. Note that the user defined default provider will always take precedence.

If you don’t want your provider to be selectable as a default provider, set the defaultProviderAllowed argument to false.

You can also completely deactivate existing providers with:

TYPO3\CMS\Core\Authentication\Mfa\Provider\TotpProvider: ~

The MfaProviderInterface contains a lot of methods to be implemented by the providers. This can be split up into state-providing ones, e.g. isActive or isLocked and functional ones, e.g. activate or update.

Their exact task is explained in the corresponding PHPDoc of the Interface files and the Core MFA provider implementations.

All of these methods are receiving either the current PSR-7 Request object, the MfaProviderPropertyManager or both. The MfaProviderPropertyManager can be used to retrieve and update the provider specific properties and also contains the getUser method, providing the current user object.

To store provider specific data, the MFA API uses a new database field mfa, which can be freely used by the providers. The field contains a JSON encoded Array with each provider as array key. Common properties of such provider array could be active or lastUsed. Since the information is stored in either the be_users or the fe_users table, the context is implicit. Same goes for the user, the providers deal with. It’s important to have such generic field so providers are able to store arbitrary data, TYPO3 does not need to know about.

To retrieve and update the providers data, the already mentioned MfaProviderPropertyManager, which is automatically passed to all necessary provider methods, should be used. It is highly discouraged to directly access the mfa database field.