Security Basics mailing list archives

Re: Thoughts on CAPTCHA


From: "Gregory Rubin" <grrubin () gmail com>
Date: Tue, 15 Apr 2008 15:32:09 -0700

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Chris,

I agree that CAPTCHAs in their current incarnation are broken but I
don't see how your solution addresses the problem.

It is easy for the computer to figure out which part of they keypad
corresponds to which number/character.  If it isn't obvious from the
source-code, then it just does OCR against the button images (and
we're back to the current problems).

Greg

P.S. I should note that there are several trojans out there now which
record not only the position of mouse-clicks but also a snapshot of
the pixes around the click specifically to defeat the protection you
described above.
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