I was struck by the CAPTCHA issue a while back too, it happens to me
that CAPTCHA reminded me of all these anti-piracy technique that have
been developed over the past 2 decades. Put this special data into
that sector of the disc so pc-tools can't copy it or install this
special cd checker to make sure the cd is not pirated. We all know the
result, finding a crack to all these protection is only a question of when.
I would say CAPTCHA is too a case of trying to fight intelligent with
more intelligent. which is an endless loop with no true winner. And so
I wonder maybe a true solution to this abuser protection issue lies
somewhere else.
I myself look at the setup this way, all these tool hacker uses depends
on one thing to function, the question being presented as part of the
signup/login procedure, because we must make the question presentable
online and friendly enough for humand to process, it is bound to be
possible to come up with some porgram to come up/brute force the answer.
So in another word, the existence of the question itself has made it
possible for hacker to come up with software to defeat the protection.
In a way, the solution has itself become the problem, so I am thinking
maybe instead of trying to improve it. We should look into eliminating it.
I can see some good example out there that is going into that
direction. Many online banking service are taking advantage of SMS,
sending user a passkey where they have to use to login to the service.
Or this implementation pay pal has implemented, that debit user's
credit card and ask user to use that sum as some form of passkey as one
of the gentlemen here has pointed out.
These solution are very expensive compare to CAPTCHA but the direction
seems to be more reliable and hack-profe. If a better solution to
CAPTCHA should be found, this maybe one direction you fellow might want
to consider.
Tor.
robert@webappsec.org wrote:
This was linked off of slashdot (http://it.slashdot.org/article.pl?sid=05/08/24/1629213&tid=172&tid=95)
and explains some of the ways people are breaking CAPTCHA (http://en.wikipedia.org/wiki/Captcha) based systems.
http://sam.zoy.org/pwntcha/
- Robert
robert_at_webappsec.org
http://www.cgisecurity.com
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Victor
Development Engineer
Outblaze Ltd
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