Comments are processed with the wp-post-comments.php file. Automated spammers (‘spam bots’) can provide (‘post’) data directly to that page, bypassing any comment processing, by using CURL/WGET commands.
The result is comment spam – and not always caught by common comment spam checkers. Akismet, for instance, looks for similar patterns of comment text, and is good at that, but comment spam can still make it past that type of comment checking.
This plugin adds a simple and changing hidden field value to the comment form. The processing of the comment form is changed to check for that hidden field. If not found, then the normal comment form entry was bypassed by the spam bot, so the comment is discarded. Otherwise, the comment is processed normally.
This is not a full solution; manually entered comment spam will not be blocked. But automated POSTs of comment data directly to the wp-post-comments.php file will be blocked.
No screenshots provided