Tag Archives: recaptcha

reCAPTCHA fails to deliver, bypassed or cracked, spam still comes through

I like(d)  the idea behind reCAPTCHA, blocking spam while helping scanning books is cool, and let’s be honest, reCAPCHA images are more readable to the human eye than the random deformed alphanumeric combinations the usual antispam codes produce.

Anyway, even if I have Akismet plugin installed, being the comments captcha’ed I expected almost no spam at all, not certainly from bots, yet it’s been a constant for me; lately, a huge wave of spam messages, almost identical, hitted the website; this also happened on the punbb forum of my professional website, where reCAPTCHA plugin was in action, and you understand that finding a spam post containing plenty of links with obscene thumbnails attached is not good for my image.

What’s the reason behind all this? Possibly reCAPTCHA pollution by special kind of keyword spamming to make certain known words always check positive, or advanced OCR techniques, or your average next door guy payed some millicent each captcha he decyphers. I don’t really care, what I know is that spam is passing through.

So I decided to drop reCAPTCHA altogether and switch to good old onsite captcha generation, let’s see what happens, there is now SI Captcha plugin installed (suppose SI stands for SecureImage, I recognize the pattern).

  This article has been Digiproved

reCAPTCHA Input error: Invalid referer and WordPress

Just today someone (thank you) pointed out there was an error with the recaptcha plugin in my WordPress comments. Checking it out, that “Input error: Invalid referer” is a generic error noone has ever pointed out to a single cause.

At first I made sure the keys used by the reCAPTCHA plugin were correct, and created a brand new website domain in the reCAPTCHA admin panel, and updated the values in the plugin settings. That way, I could see the captcha image correctly when loaded while being logged in, but as soon as I logged out the error was back there. I checkd the page source, and I noticed the “challenge” value of the HTML line that called the external javascript was different from the public key I updated in the plugin settings.

After some thinking, it turns out that the WP Super Cache plugin in some cases interferes with reCAPTCHA plugin, as it caches the old plublic key value which of course makes reCAPTCHA mad. Clearing the cache, thus reloading the whole page, solved the problem, and the captcha image was back there to be solved.