Spam attack on the Wiki

[Vladimir Panteleev via Digitalmars-d]

On Monday, 11 August 2014 at 08:23:15 UTC, Marc Schütz wrote:
> Could one of the Wiki admins have a look, please? There is a 
> spam attack ongoing on wiki.dlang.org. Nothing massive, just a 
> handful of pages so far, but better to stop it. Thanks!

The CAPTCHAs in use on the forum and wiki successfully block all 
of the fully-automated spam coming from spam-bots. However, 
unfortunately, they are not very effective against humans who are 
paid to post spam by hand (usually low-paid workers from 
developing countries).

During registration or when adding new links to external sites, 
the D Wiki would ask for one of two questions:

* Who is the creator of the D programming language?
* Who is the author of the book "The D Programming Language"?

The idea was to have questions with non-obvious answers, which 
would be obvious to experienced D users, Google-able for others, 
but still presenting too much of a bother for spammers. 
Unfortunately, as we've seen, this has turned out to be not 
enough.

I've now implemented a new CAPTCHA for the D wiki, which 
challenges would-be editors with randomly-generated questions (so 
that they are not Google-able). Basic programming knowledge is 
required for all of them, and some require some familiarity with 
D syntax. Hopefully, this should still be inclusive enough for 
most editors.

You can demo the CAPTCHA on the following page, so you don't have 
to clutter the wiki with test accounts or edits:

http://wiki.dlang.org/extensions/DCaptcha/demo.php

Source code:

https://github.com/CyberShadow/dcaptcha

https://github.com/CyberShadow/DCaptcha-MW (MediaWiki adapter)

Pull requests for more challenges are welcome. I plan to 
integrate the CAPTCHA into DFeed (forum.dlang.org) as well.