I don't have any spammer problems but I was thinking of this if I ever do. first create this plugin in newthread_start:
PHP Code:
if($_REQUEST['do'] == 'postthread' AND !$_REQUEST['a'])
{
print_no_permission();
}
Then edit in "&a=b" in the form action in the newthread template so it looks like this:
HTML Code:
<form class="vbform block" action="{vb:raw $vboptions.vbforum_url}{vb:if "$vboptions['vbforum_url']", '/', ''}newthread.php?do=postthread&f={vb:raw forumid}&a=b" method="post" name="vbform" onsubmit="return vB_Editor['{vb:raw editorid}'].prepare_submit(this.subject.value, {vb:raw vboptions.postminchars})">
I'm assuming these are bots that never actually load your new thread page but simply submit a server request directly. With the modified form action such requests will be filtered out. If you're good at coding and you are 100% confident this is working properly you could also write a query that would delete any "user" that made a direct server request.
These instructions are for vB4xx!