How to prevent URL's in post subject?

[BSD2000]

My forum has been flooded with spammers lately and I installed a few anti-spam measures to slow them down, including preventing them from posting URL's in the body of the message, but they are getting around that by posting spam URL's in the subject line.

I've searched high and low and I can't find a mod that prevents 'http://' URL's from being entered in the subject line. Is there a small bit of code I could add in the post template that would show an error message if a URL is entered as the subject?

[vbgamer45]

Open sources/Post.php

Find

Code Select Expand


// You are not!
if (isset($_POST['message']) && strtolower($_POST['message']) == 'i am the administrator.' && !$user_info['is_admin'])
fatal_error('Knave! Masquerader! Charlatan!', false);

Add after

Code Select Expand


if (substr_count($_POST['subject'],"http://") > 0 || substr_count($_POST['subject'],"https://") > 0)
{
fatal_error('You are not allowed to use that subject line', false);
}


[BSD2000]

Works perfectly! Thank you so much! 

[vbgamer45]

Glad to help

[BSD2000]

I made one small change - I added strtolower() to force the subject text to all lowercase, just in case they try to bypass it using uppercase letters:

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if (substr_count(strtolower($_POST['subject']),"http://") > 0 || substr_count(strtolower($_POST['subject']),"https://") > 0)
{
fatal_error('You are not allowed to use that subject line', false);
}

Works even better now. 

[BSD2000]

Now that I think about it, you could add a new error message in the file /Themes/default/languages/Errors.english.php file, like this:

Code Select Expand

$txt['error_bad_subject'] = 'You are not allowed to use that subject line.';

Then change the code in /Sources/Post.php to:

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    // HTTP not allowed!
    if (substr_count(strtolower($_POST['subject']),"http://") > 0 || substr_count(strtolower($_POST['subject']),"https://") > 0)
        {
       $post_errors[] = 'bad_subject';
        }


And it will produce an error message that stays focused on the post, but lets them know there's a problem with the subject text, like the attached photo. 

[vbgamer45]

Yup that is the best way!

[Kindred]

Or, even better... prevent them from reistering in the first place.

See the FAQ entry on how to prevent spammers

[GerryM]

See the FAQ entry on how to prevent spammers

Which FAQ?

[Illori]

https://wiki.simplemachines.org/smf/Spam_-_my_forum_is_flooded_with_spam,_what_can_I_do