Drupal is no doubt one of the best content management systems out there and is being used by thousands of sites across the world. The system is very secure but as soon as some security vulnerabilities are found it may be prone to attack/spam. I recently had a client's website being spammed (hundreds of user accounts were being created everyday) so I started looking for some solutions and came across these modules which are extremely effective at stopping spam.
- Spamicide: The Spamicide module prevents spam submission to any form on your Drupal website. Spamicide adds an input field to each form then hides it with CSS. When spam bots fill in the field, the form is discarded.
- Spambot: The Spambot module protects the user registration form from spammers and spambots by verifying registration attempts against the ‘Stop Forum Spam’ online database. (www.stopforumspam.com)
- Email Verification: The Email Verification module checks that the email address exists when it is entered by the user.
- reCAPTCHA: The reCAPTCHA module uses web service to improve the CAPTCHA system and protect email addresses.
- Login Security: The Login Security module improves the security options in the login operation of a Drupal site.
- Register Country: The Register Country module is designed to intercept new registrations and check if the IP address being used is registered to a country that the site administrator has chosen.