Feature: #93825 - Rate limiting for failed logins

See Issue #93825

Description

The TYPO3 backend and frontend login now uses a rate limiter by default, which prevents further authentication attempts for an IP address, if a configurable amount of login attempts is exceeded in a given time.

The hardcoded wait time of 5 seconds after a failed login has been removed, since it offers no real protection against brute force attacks and may result in unwanted side effects.

Important

Rate limiters do not provide a useful protection against DoS attacks. They should be used to limit the amount of requests to certain routes (for example login or form submission) of an application.

Impact

TYPO3 ships with a rate limiter for backend and frontend authentication. It implements the “Sliding Window Rate Limiter” allowing to define a maximum amount of login attempts for a given range of time before further login attempts will be denied for the remote IP address.

A configurable list of IP addresses allows to exclude certain IP addresses or IP address blocks from being rate limited.

The rate limiter utilizes the TYPO3 caching framework as storage for rate limiter states. The rate limiter takes care of garbage collection for affected cache tables on every login request.

Note, that clearing the system cache will purge all limiter states.

Backend login

The rate limiter Symfony\Component\RateLimiter\LoginRateLimiter for the TYPO3 backend login is enabled by default and configured with the following default values:

  • Maximum 5 login attempts for a timeframe of 15 minutes
  • No IP address excluded

When the maximum amount of login attempts has exceeded, a \TYPO3\CMS\Core\RateLimiter\RequestRateLimitedException exception is thrown. The exception implements \TYPO3\CMS\Core\Error\Http\AbstractClientErrorException resulting in a user readable error message together with a 403 HTTP status code.

Configuration

The rate limiter for the TYPO3 backend can be configured using the Settings module or the Install tool. The following new configuration values are available:

$GLOBALS['TYPO3_CONF_VARS'][BE][loginRateLimit] = 5;
$GLOBALS['TYPO3_CONF_VARS'][BE][loginRateLimitInterval] = '15 minutes';
$GLOBALS['TYPO3_CONF_VARS'][BE][loginRateLimitIpExcludeList] = '';

Setting [BE][loginRateLimit] = 0 will disable rate limiting. The same applies, if [BE][loginRateLimitIpExcludeList] = '*' is configured.

The provided defaults for [BE][loginRateLimitInterval] can be customized in AdditionalConfiguration.php by configuring a date/time string following PHP relative formats.

Frontend login

The rate limiter for the TYPO3 frontend login is enabled by default and configured with the following default values:

  • Maximum 10 login attempts for a timeframe of 15 minutes
  • No IP address exclude list

When the maximum amount of login attempts is exceeded, a \TYPO3\CMS\Core\RateLimiter\RequestRateLimitedException exception is thrown. The exception implements \TYPO3\CMS\Core\Error\Http\AbstractClientErrorException resulting in a user readable error message together with a 403 HTTP status code.

Configuration

Configuration is similar to the rate limiter for the backend login.

The following new configuration values are available:

$GLOBALS['TYPO3_CONF_VARS'][FE][loginRateLimit] = 10;
$GLOBALS['TYPO3_CONF_VARS'][FE][loginRateLimitInterval] = '15 minutes';
$GLOBALS['TYPO3_CONF_VARS'][FE][loginRateLimitIpExcludeList] = '';