Symfony security.yml Unrecognized options "check_path, login_path, provider" under "security.firewalls.secured_area.ldapsecure"

I'm getting this error when trying to configure a custom authentication provider using Symfony 2.6.

Unrecognized options "check_path, login_path, provider" under "security.firewalls.secured_area.ldapsecure"

Here's my security.yml

security:
  encoders:
    Symfony\Component\Security\Core\User\User: plaintext
  role_hierarchy:
    ROLE_ADMIN:       ROLE_USER
    ROLE_SUPER_ADMIN: [ROLE_USER, ROLE_ADMIN, ROLE_ALLOWED_TO_SWITCH]
  providers:
    ldap_provider:
      id: ldap.security.user.provider
  firewalls:
    login_firewall:
      pattern: ^/app/login$
      anonymous: ~
    secured_area:
      pattern: ^/
      ldapsecure:
        check_path: app_security_login_check
        login_path: app_security_login_path
        provider: ldap_provider
    dev:
      pattern:  ^/(_(profiler|wdt)|css|images|js)/
      security: false
  access_control:
    - { path: ^/app/login, roles: IS_AUTHENTICATED_ANONYMOUSLY }
    - { path: ^/, roles: ROLE_USER }

The ldapsecure "factory" class exists and if I change the getKey() method to return someone else, it breaks differently, so the ldapsecure is being recognized. But I can't see why it's not accepting check_path, login_path or provider. If I change ldapsecure to form_login, I don't get the error, it's just not using my authentication provider.

So I feel like I'm missing something, but don't know where to look at this point.