So I have quite a bit of spam which is posted to my site, probably between 50 and 100 comments a day at least. I’ve been using some heavy handed spam filters to try and curb it, but these filters have probably blocked legitimate comments, which kind of defeats the purpose of having a blog. One solution is to use a Captcha instead of a spam filter, but these are generally easy to circumvent with a bit of programming to defeat the Captcha. What I’ve done is created my own unique Captcha system, which is probably not worth the effort for anyone to crack (given that I have only 1 site using the Captcha so the reward for solving it is minimal). This should block spam computer programs from posting comments to my blog, and so I’ve (at least temporarily) disabled the anti-spam filters.
The solution is unfortunately not accessible. I will look into a way of providing an audio file replacement in case anyone who is visually impaired is reading my blog and wants to comment. For now, if that is the case, please feel free to use the contact link above.
Could you please test that this Captcha works for me? I want to verify that I have not accidentally made it impossible for anyone to comment.
Update:
It seems that my Captcha works. I’ve received only 3 spam since I implemented it, all of which could have easily been entered by a human being. Comparing this to the hundreds and hundreds of spam I used to receive in the same time period makes me happy. Hopefully this mean that it will be also easier for actual human beings to comment on my blog.
Here’s 3 minutes of my website log. Almost all of the rest of my log is filled with similar mesages, so I’m encouraged by the success of my Captcha module. Some spam has gotten through, but so far it seems that it is either infrequent, or I can block the spammer by IP address.
catelli_nqu says:
Testing Captcha
October 3, 2012 — 9:15 pm
catelli_nqu says:
Test 2
October 3, 2012 — 9:16 pm
Anonymous says:
*insightful comment*
October 5, 2012 — 2:51 pm
Serjio says:
I like your capthca, it’s easy and readable. I have those curved and twisted letters that are impossible to read
October 8, 2012 — 5:02 am
David Wees says:
Easy for you to read, harder for a computer. Hard enough that it will take some work for someone to write a Captcha interpreter, which I’m hoping isn’t worth it for the only site using this style of Captcha – mine.
October 17, 2012 — 3:59 pm
Steve Roy says:
Hi David,
I use Drupal as well as you and I have the exact same problem: so much spam it’s driving me nuts. Even using the CapTCha module provided by Drupal doesn’t make a difference. So now, I’m trying a spam filter (MOLLOM) to see if it can make a difference, but I still receive a lot of spam, but a little less than before.
I’m curious to know how you created your Captcha module. I might be interested in trying something similar.
Thanks,
Steve Roy
October 17, 2012 — 2:30 pm
David Wees says:
If you download one of the simple Captcha modules (and know some PHP code) and examine its code you’ll find creating a Captcha isn’t actually that hard. It’s a single hook in the module. The trick is creating a Captcha that a human finds easy, and a machine finds hard. In my case, I’m relying on the fact that most spam robots written almost certainly don’t include a full CSS interpreter, which is basically required to decipher the Captcha code by machine. If you look at the source for the word required by my Captcha, you may be able to figure out which trick I’m using.
October 17, 2012 — 3:57 pm