About

This simple Squirrel Mail plugin prevents spam bots from sending email using the squirrel mail web interface. Using the Captcha system it distinguishes from humans and computers.

Requirements

PEAR::Text_Password - for password generation (already included in the distribution)

GD Library - for image generation (png / jpg / gif)

Instalation

1. Download the source code from here:

   http://opensource.dazoot.ro/member/catalin/squirrelmail_captcha/download/compose_captcha-0.1.tar.gz

2. Unzip the archive into the squirrel mail plugins folder

3. Patch compose.php to support the new feature like follows:

   After the subject field is "printed" add a call for do_hook('compose_after_subject');:

   echo '         '.addInput('subject', $subject, 60).
        '      </td>' . "\n" .
        '   </tr>' . "\n\n";
   
   // begin here
   do_hook('compose_after_subject');
   // end here
   
   if ($location_of_buttons == 'between') {
       showComposeButtonRow();
   }
   
   /* why this distinction? */
   if ($compose_new_win == '1') {
   

   Now add the check in the checkInput function, when the Send Button is pressed:

   function checkInput ($show) {
       /*
        * I implemented the $show variable because the error messages
        * were getting sent before the page header.  So, I check once
        * using $show=false, and then when i'm ready to display the error
        * message, show=true
        */
       global $body, $send_to, $send_to_bcc, $subject, $color;
   
           // begin here
           if (strcasecmp($_SESSION["captcha_phrase"], $_POST["captcha_phrase"]) || strlen($_POST["captcha_phrase"])<1 )
           {
                   if ($show) plain_error_message(_("The verification code is incorrect."), $color);
           return false;
           }
           // end here
           
           if ($send_to == '' && $send_to_bcc == '') {
               if ($show) {
                   plain_error_message(_("You have not filled in the \"To:\" field."), $color);
               }
               return false;
           }
       
       
       return true;
   } /* function checkInput() */   
   

4. Run ./configure from the squirrelmail root folder and add the compose_captcha plugin.

Screen Shots

Here are some screenshots with the compose page using the captcha plugin:

1. Romanian language with white background for the captcha code:

   

2. English version with transparent background for the captcha code and the error message when the code is not entered corectly:

   

Suggestions

Other suggested plugins for antispam sending from SquirrelMail:

Restrict Senders - limits the nr of recipients per mail and also the number of mails / day for an user.

Links: Open Source, Squirrel Mail, PHP PEAR