blank form submission with captcha
Printed From: Web Wiz Forums
Category: Web Wiz Web App Support Forums
Forum Name: Web Wiz CAPTCHA
Forum Description: Support forum for the Web Wiz CAPTCHA security image.
URL: https://forums.webwiz.net/forum_posts.asp?TID=25539
Printed Date: 28 March 2026 at 10:35pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com
Topic: blank form submission with captcha
Posted By: weblake
Subject: blank form submission with captcha
Date Posted: 04 April 2008 at 3:44pm
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Hi, I hope someone may be able to shed some light on an issue we are having. We are using captcha (have been for about six months) on our site after being hit by spammers through our contact form.
The form uses captcha and if the captcha is completed the contents of the form are emailed to the client. Also we have form validation so if a human is submitting the form even with the correct captcha the form cannot be submitted.
For the past month though our client has been getting blank emails from the site. This suggests that something is managing to bypass the captcha - but not filling in the form - which has validation.
Has anyone else experienced this problem? I noticed that Bruce has mentioned elsewhere that if the images are noted then a bypass can be created - but we cant understand how the captcha and form validation can both be bypassed. I need to find a solution to this problem for my client.
Any feedback would be greatly appreciated.
Many thanks in advance.
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Replies:
Posted By: WebWiz-Bruce
Date Posted: 04 April 2008 at 9:34pm
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You should test file that sends the email to see if it can be directly submitted to and if it can are their stops to prevent the code that sends the email from running. A new version of Web Wiz CAPTCHA is also being developed and is only weeks away from release. The new version, instead of displays one of the 200+ images in it's library will create bitmap images on the fly. The added bonus to this method is not only will it be more secure with randomly created images on the fly, but you will be able to configure the colours, distortion level, type of distortion, etc. yourself in a setup file. ------------- https://www.webwiz.net/web-wiz-forums/forum-hosting.htm" rel="nofollow - Web Wiz Forums Hosting https://www.webwiz.net/web-hosting/windows-web-hosting.htm" rel="nofollow - ASP.NET Web Hosting |
Posted By: weblake
Date Posted: 05 April 2008 at 11:39am
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Many thanks for your reply Bruce. I understand your response and will look into it.
I look forward to the new release and will inform my client that this will be the way to go when it's available.
Kind Regards
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Posted By: Scotty32
Date Posted: 05 April 2008 at 11:40am
This maybe a silly question, but is the validation done by Javascript or ASP? As if its javascript - it will be extremely easy to bypass, and would need ASP validation added as well. ------------- S2H.co.uk - http://www.s2h.co.uk/wwf/" rel="nofollow - WebWiz Mods and Skins For support on my mods + skins, please use http://www.s2h.co.uk/forum/" rel="nofollow - my forum . |
weblake wrote: