Antibot

Concept: Requires JavaScript to display the form and blocks submission processing until human user interaction detected (mouse move, key press, mobile swipe gesture... the action of the form is then switched back to the path that it was originally set to be).

Log of blocked attempts: NOT Available.

UI to enable protection for certain forms: Available.

The Tarpit module allows you to build a tarpit on particular url that you can define.
When the spammer visit those links, a special page with text and links is displayed.
If he continue crawling on those links, after a depth limit, an action that you can define is triggered.

The module is bundled with multiple submodules that you can enable according to your needs.

In OpenAid1 a CAPTCHA module is used. In OpenAid2 the Honeypot module is used.

OpenAid1 CAPTCHA

The OpenAid CAPTCHA module adds a CAPTCHA to the following forms by default:

• Blog comment form
• Page comment form
• Contact form
• User registration form

This can be configured further at Configuration > People > CAPTCHA or admin/config/people/captcha.

A CAPTCHA is a program to distinguish between computer bots and humans on websites in order to stop spam and fraudulent registrations from bots.

Confident CAPTCHA is a free CAPTCHA service and Drupal module. This documentation is written to explain how to configure and install the Confident CAPTCHA module.

(1) Obtain Key Credentials
The Confident CAPTCHA web requires you to create a unique key credential. To obtain an API key credential, register at http://www.confidenttechnologies.com/Get_Confident_CAPTCHA and create an account.

(2) Download the Confident CAPTCHA module. The module version must be compatible with your version of Drupal.

(3) Extract the files. When you first get the module, it will appear in a compressed file format such as 'tar.gz'. On Windows, use a program like 7-zip to extract it.

(4)Upload the folder. FTP your files to the desired modules folder in your Drupal installation. The modules folder at the top level of your Drupal installation is reserved for Drupal core modules (the ones that come with the original download of Drupal). So, you should generally create a sites/all/modules/ directory and put uploaded modules there.

Drupal 6

1. Go to Administer > User Management > CAPTCHA and check: Add CAPTCHA administration links to forms.
2. Create the Webform. Do not click on the CAPTCHA link at the bottom of the Form Create page.
3. Save the form.
4. Click CAPTCHA: no challenge enabled at the bottom of the newly created form (when Viewing, not editing the form).
5. Click Place a challenge here for untrusted users.
6. Done.

Drupal 7