Joomla 2.5/3.0 Default Security:
Captcha: (Note: possible issues with plugin and Google captcha)
Captcha in the core: A native captcha solution will be part of Joomla 2.5. The core will come with a reCaptcha plug-in but extension developers can supply their own solutions. This CAPTCHA plugin uses the reCAPTCHA service to prevent spammers while it helps to digitize books, newspapers and old radio shows. To get a public and private key for your domain, go to http://google.com/recaptcha. To use this for new account registration, go to Options in the User Manager and select Captcha reCaptcha as the Captcha.
Active defenses from intrusions and hacker attacks
MD5 Comparison Tool - http://extensions.joomla.org/extensions/tools/security-tools/15379
Captcha - ReCaptcha (native plugin) - This CAPTCHA plugin uses the reCAPTCHA service to prevent spammers while it helps to digitize books, newspapers and old radio shows. To get a public and private key for your domain, go to http://www.google.com/recaptcha. To use this for new account registration, go to Options in the User Manager and select Captcha - reCaptcha as the Captcha.
System - Marco's SQL Injection - LFI Interceptor - A simple sql injection / local file includes preventer plugin
System - osolCaptcha (Simple Captcha) - Easily add captcha to joomla forms for login,registration and contact us. Make sure that you publish this component,from here. For adding captcha in other forms just put in the HTML of the form where you want the captcha to show: ''<?php global $mainframe; //set the argument below to true if you need to show vertically( 3 cells one below the other) $mainframe->triggerEvent('onShowOSOLCaptcha', array(false)); ?>''
System - EasyCalcCheck PLUS - ECC+ (Very Robust Captcha) - Protects Joomla! core forms and 3rd party extensions through the integration of anti-spam (reCaptcha, Akismet, Honeypot Project, StopForumSpam, Mollom, Bot-Trap, Botscout) services and adds an arithmetic problem, a hidden field and a time lock. Supported 3rd party extensions: AlfContact, Community Builder, DFContact, Easybook Reloaded, Fox Contact, Flexi Contact, JomSocial, Kunena Forum, Phoca Guestbook and Virtuemart. The plugin can also protect the backend with a token. Have Fun - No Spam! :-) Please post a rating and a review at the Joomla! Extensions Directory: EasyCalcCheck Plus in the JED - Thank you!