Problems with SPAM? Read this!

Post by **Klemen** » Fri Oct 13, 2006 8:32 pm

EDIT (24th April 2007): a new version of Hesk is out with the anti-SPAM image available so no need to install any add-ons anymore.

Hi,

As a temporary solution before the next version is out, here is a SPAM PATCH for Hesk 0.93.1:
http://www.phpjunkyard.com/extras/hesk0 ... _patch.zip

Read the README.txt file inside for instructions. Requires GD library for PHP to be enabled on your server.

Problems, questions, ... please post HERE and DON'T start a new topic!

Regards

mikeda · Post by **mikeda** » Sat Oct 14, 2006 5:58 am

it works

thank you for this service !!!

greating
Michael

johnny-legend · Post by **johnny-legend** » Sat Oct 14, 2006 11:43 am

You maybe want to take a look at this: http://sam.zoy.org/pwntcha/

I'd be happy if you let us change two things: background images, better multiple and different fonts.

Your CAPTCHA looks similar to the old vBulletin one which was not very secure. It does not have to become secure like my one but something like that:

But anyway thanks for your efforts.

Post by **Klemen** » Sat Oct 14, 2006 12:23 pm

Hi,

Thanks for the input. I know captcha's can be defeated, but luckily the vast majority of spammers are [insert word(s) of your choice] and the one I use throughout my site works well... at least for now.

The idea behind Captcha is to make images not readable by computers, but readable by humans. Looking at the image you posted it sure is a tough nut for an algorithm (although the text is different color codes than background so it could be extracted quite efficiently), but on the other hand it is very hard to read it for me as well. What does it say? "CHsn"? Are there hidden "D" and "6"?

Try showing your image to a senior person...

Also if the background is always the same (even if it is distorted and colorful) then it isn't much help anyway.

The YAHOO one is a very good one, easily readable by humans but good protection against bots:
https://edit.yahoo.com/config/eval_regi ... l=us&new=1

I guess at the end it all comes down to how much protection you need. A big busy and always targeted by fraudsters website needs better protection then a simple script used on a few thousand websites. If a simple captcha does the job then why complicate?

Post by **Klemen** » Sat Oct 14, 2006 12:43 pm

One other important thing to consider (but usually ignored) when making/using Captcha's, according to Wikipedia about 7 percent of the male population and about 17.28 percent of the female population in the US have some sort of color blindness.

johnny-legend · Post by **johnny-legend** » Sat Oct 14, 2006 1:05 pm

Well I don't have that kind of audience on my website so it isn't neccesseray to be that readable. The picture was just an example, as I said it does not have to be as hard like mine.

Btw the picture says: pC6HSn

That CAPTCHA is only used for registration at my forum on which you can refresh the image so it does not even has to be the first image, but I can be sure that there will be no spammer registering.

P.S. people love challenge

Post by **Klemen** » Sat Oct 14, 2006 1:46 pm

I think it might be a good idea to log how many times your users enter the wrong code if all your images look similar to the one you posted

johnny-legend · Post by **johnny-legend** » Sat Oct 14, 2006 3:58 pm

Okay maybe this is a better example:

Post by **Klemen** » Sat Oct 14, 2006 7:03 pm

Yes, this is better regarding readability. But the problem with such Captcha's is that font color is different than the background (the perturbation) meaning it's quite easy to divide letters and numbers from the background using an algorithm. It would of course take much more work than simply dividing black from white background it is indeed doable in the same manner.

If you look at the reference you gave (http://sam.zoy.org/pwntcha/) the best Captcha's are those in merely two colors, for example "Passport" or "Yahoo" one. This makes them easier to read by humans.

If I decide to develop the images used by my scripts further in the future this is probably the way I will go. Use black on white, rotate and distort the font and add some perturbation in the same color as the code.

But for now I have no plans on doing that, except maybe educational nature (to educate myself more about generating such images

)

johnny-legend · Post by **johnny-legend** » Sat Oct 14, 2006 8:14 pm

All I need is the option to change background and font so everybody can change the captcha or stick with your version.