Enable reCAPTCHA for Control Panel .htaccess Through Rewrite Rules
Use one of the following rewrite rule directives in control panel virtual host document root .htaccess:
[E=verifycaptcha] will always redirect to reCAPTCHA until verified.
ACTION can be
deny to return a 403 or
drop to drop the connection when Max Triesis reached. Until Max Tries is reached, the client will be redirected to reCAPTCHA.
RewriteCond SOME-CONDITIONAL-CHECK RewriteRule .* - [E=verifycaptcha]
SOME-CONDITIONAL-CHECK would be a suspicious UA, IP address, etc.)