ECC+ - EasyCalcCheck Plus
Protects Joomla! core forms and 3rd party extensions through the integration of anti-spam services and adds an arithmetic problem, a question, a hidden field and a time lock.
Supported 3rd Party Extensions in the Joomla! 2.5 version: aiContactSafe, AlfContact, Community Builder, DFContact, Easybook Reloaded, Fox Contact, Flexi Contact, Flexi Contact Plus, JomSocial, Kunena Forum, Phoca Guestbook and Virtuemart
With the powerful custom call feature every form can be protected in Joomla! with a special syntax.
Integrated external antispam services: Google ReCaptcha, Akismet, Honeypot Project, StopForumSpam, Mollom, Bot-Trap, Botscout
Protects the backend via a token. Only with the right token, the administrator login site can be opened!
Also included: SQL Injection and Local file Inclusion protection.
Have fun and NO spam! :-)
Joomla! 3 - https://joomla-extensions.kubik-rubik.de/downloads/ecc-easycalccheck-plus/joomla-3
Joomla! 2.5 - https://joomla-extensions.kubik-rubik.de/downloads/ecc-easycalccheck-plus/joomla-25
The extension is completely free, but you need a subscription for support: