Miscellaneous Hacks - Enhanced Captcha Image Verification - stop bots from signing up!!

Title : Enhanced Captcha Image Verification

Version : 1.1

Coder : Andy Calderbank & Jason Williams

Purpose : Add extra Image Verification to the registration process, using an alternative system to the Captcha system.

Why : It would appear that spammers can now "read" the Captcha codes and overcome the verification process.

How : This extra feature uses images which are harder for a spam program/bot to interpret than text characters. The user has a choice of 4 randomly displayed images, and the answer is given below. The user must click on that image to proceed, if the incorrect image is selected an error message is shown. The images are randomly shown (from however many are in the directory - you can have as many as you want, just has to be more that 4!) and are automatically created from the images/verification/ directory - all on the fly. Sample images are included with this release, but you can use your own - I recommend using 100 x 100 pixels, in .jpg format and naming the image with a meaningful title (ie A House.jpg) - the extension is stripped so only the filename itself is shown.

To further enhance security, the images are passed through a script which means that none of the images on the screen have file names - and cannot be associated to the question by title alone.

I have been testing this on my forum and have found it to be effective - I cannot guarantee that this will stop all spamming, but this relies more on human input than a computer "reading" the image.

Important : This has been tested on 3.6.2 - I cannot guarantee it will work on anything above, please test with caution - and as always BACKUP FIRST! This will not work on anything below 3.6.0.

Demo : http://www.steadiforum.com/register.php

I hope this is help to the VBulletin community as I know this is a growing problem. I don't fancy the thought of trawling through hundreds of new members deleting stupid usernames and spam posts.

Installation :

1. Upload the verification/ directory to your images/ folder - make sure .htaccess and show.php are present - otherwise it won't work.
2. Import Product - product-image_verification.xml

Upgrading :

1. Upload show.php to the images/verification/ directory.
2. Import Product - product-image_verification.xml - select Allow Overwrite to enable upgrade.

Requirements : GD Libraries installed

File uploads : 39 (including images)
Files to Import : 1
New Templates : 1
New Phrases : 5
Uses Hooks : 1
New Queries : 0

History :
v1.0 - Original release
v1.01 - Slight code change for forums in sub-directories (thanks go to Barakat for solving this one)
v1.1 - Issue resolved with Windows servers also template clean up for xhtml compliance
v1.11 - Added version check function, minor upgrade.

Done - if you like please click install! (and I won't ask for any donations as long as you click Nominate for MOTM!)

Don't forget you don't have to use the provided images - you can customise these to any you wish - I've used ones that are hopefully universal and everyone will recognise.

[Antivirus]

very nifty idea, great way around the bot problems. If we start haivng an issue with this, will def install.

[steadicamop]

I had one determined Spam Bot make it through today - it has taken them a long time, so to increase security slightly, I've increased the number of images from 4 to 6 - if anyone else wishes to do this, here's how to:

AdminCP -> Plugins & Products -> Plugin Manager -> Extra user verification - click edit then find this code :

$amount_of_images_to_show = 4;

Change this to the number of images you want (I went for 6, adds just two extra but makes it that little bit harder for Bots):

$amount_of_images_to_show = 6;

Click Save then go to:

Styles & Templates -> Style Manager -> [Your Style] -> Edit Templates -> image_verification

In that template find:

      
<a href='register.php?clicked=1'><img src='images/verification/show.php?1' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=2'><img src='images/verification/show.php?2' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=3'><img src='images/verification/show.php?3' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=4'><img src='images/verification/show.php?4' border='0' alt='VB RegSecure' /></a>

All you have to do is add each line for the extra image you use - for six images this is what it looks like.

<a href='register.php?clicked=1'><img src='images/verification/show.php?1' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=2'><img src='images/verification/show.php?2' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=3'><img src='images/verification/show.php?3' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=4'><img src='images/verification/show.php?4' border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=5'><img src='images/verification/show.php?5 border='0' alt='VB RegSecure' /></a>
<a href='register.php?clicked=6'><img src='images/verification/show.php?6' border='0' alt='VB RegSecure' /></a>

Either use less or more depending on how you prefer it - 6 seems like a decent enough number to make it harder for them to get in.

Hope this helps,

Jason

[ShackMaster]

Thanks, I just changed mine to 6.

Occasionally I get a red X on one or two of the images. Any idea why?

Thanks again!

[steadicamop]

If your using the images that came with package it may just be a case of it hasn't loaded in time, which I doubt, the only other possibility is that the image isn't there - the script is dynamic and uses all the images.

Another to check for is that Thumbs.db has a capital T - lower case would be parsed into thinking it's an image, if you get chance right click and find out the file name.

Cheers

Jase

[Prince]

great hack, it is reduced spam on my board to almost zero!

how do you know it was a "bot" and not a real person trying to register and spam?

[ShackMaster]

Originally Posted by steadicamop

If your using the images that came with package it may just be a case of it hasn't loaded in time, which I doubt, the only other possibility is that the image isn't there - the script is dynamic and uses all the images.

Another to check for is that Thumbs.db has a capital T - lower case would be parsed into thinking it's an image, if you get chance right click and find out the file name.

Yes, all images are the ones with the package. All the images are there and I can simply right click the white box/red X and click "Show Picture" and it will show. It's generally the last one or two that don't fully load... show.php?5 and show.php?6.

It does happen frequently... you can look at it and see if it happens with you any:

http://www.hometheatershack.com/forums/register.php

Thanks!
Sonnie

[steadicamop]

Hmmm that is damn strange - when the pages loads I usually get all six, then a refresh usually shows four, another refresh shows just two then a final refresh shows a 403 error! There is something very unusual going on there - I'm asking some people I know to see if we can figure out what it might be, but to me it looks like a server issue - but if I find anything out I will let you know.

I would suggest trying 4 images again and see what happens - if that works then it might be worth sticking with that.

Cheers

Jason

[ShackMaster]

Actually I was getting 1 missing image all along with it set to 4.

[steadicamop]

Hmmm - very strange, will see what I can find out, it's very unusual.

Do you find any other images don't load on your forum?

[Prince]

I don't see how increasing it to 6 images over 4 would help anything.