[PLUG-TALK] Captcha and wikispam

[Keith Lofstrom]

On Sun, Feb 27, 2011 at 04:03:59PM -0800, Nathan W wrote:
> i also agree that it should be pretty straightforward to implement even a simple
> form of captcha which would be effective without being obstructive. maybe
> waiving the need for captcha completion under certain conditions such as length
> of membership, or number of prior posts.

I have had some form of captcha since day one.  Questions such as
"how many seconds in an hour" and "what orbits the earth?".  Three
acceptable answers for the latter, BTW.  Spam gets in anyway. 

The previous version, running on Kwiki, was hacked to present a six
digit number (as a graphic), and the user is asked to type in the
difference when that is subtracted from 999999.  They still got in.

Humans are answering the captcha questions, not bots.  I am either
dealing with some low paid slaves, or else the spammers are using
the "porn site captcha reroute" trick.  Spammer bots sometimes
screenscrape the wiki question, and present that on a porn website
to users seeking free porn.  The humans answer the question, and
get the porn, and bot uses the answer to get into websites where
they don't belong.  I first heard about this nasty trick from
"Commander Taco", the guy who runs Slashdot.

I have some rather visible wikis, high google rank, and tempting
targets.  The IP addresses for the spammers are usually in the
Phillipines.  I am considering blacklisting the whole country for
edits.  The usual spam is for term paper mills, but sometimes 
other crap.  Given that the spam is sometimes weaved syntactically
into the page content, I suspect the work is done by the same
humans who write the term papers.  Which is very, very sad.

If the spammers create new pages, I usually change the content to
indicate that the product/service is criminal, and that customers
are likely to be defrauded.  Then I lock the page.  I keep hoping
the spammers will see some business loss, and stop bothering me.

In the long run, I'm hoping the wiki readership will do the work
for me, like they do for Ward and others.  And if I lock the
wiki against edits from the Phillipines, I hope to develop some
legitimate Filipino readership, who will track down the spammers
and do things to them that I don't want to think about.  Best, of
course, would be to create better jobs for the term paper slaves,
and strip the spammers of cheap labor.

Keith

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs