Block if uploaded file is Binary in Contact Form 7

Question

Can somebody please help in blocking the binary files in contact form 7 i.e if game.exe is renamed as game.docx and uploaded then it has to be blocked

So far i've tried adding the below code in wp-includes/functions.php

add_filter('wpcf7_validate_file*', 'cf7_custom_file_validation', 10, 2);
add_filter('wpcf7_validate_file', 'cf7_custom_file_validation', 10, 2);

function cf7_custom_file_validation ($result, $tag) {
    if ($tag->name === 'your-file') {
        $contentType = mime_content_type($_FILES[$tag->name]['tmp_name']);

        if ($contentType !== 'application/docx' && $contentType !== 'application/pdf' && $contentType !== 'application/doc'&& $contentType !== 'application/rtf') {
            $result->invalidate($tag, 'This file type is not supported');
        }
    }

    return $result;
}

This allows me to upload the pdf files and it checks for pdf if binary and blocks. but in rtf, doc and docx it doesn't work

Answer 1

This is because you are checking for wrong mime-types.

.doc: application/msword
.docx: application/vnd.openxmlformats-officedocument.wordprocessingml.document