Comments on: Breaking CAPTCHAs http://blackwidows.co.uk/blog/2007/10/06/breaking-captchas/ The meanderings of a black widow... Fri, 21 Nov 2008 08:21:34 +0000 http://wordpress.org/?v=2.6.3 By: Steve http://blackwidows.co.uk/blog/2007/10/06/breaking-captchas/#comment-46524 Steve Tue, 16 Oct 2007 20:55:00 +0000 http://blackwidows.co.uk/blog/?p=147#comment-46524 When recently confronted with an application utilizing CAPTCHA that stated "Visually impaired users will require sighted assistance to ...", I asked a few technology security specialists about the efficacy of this technique. The comments were quite similar: "If the target is attractive enough, it is easy to outsource the breaking of it." Conclusion: don't rely on CAPTCHA to protect attractive targets. P.S. Don't invite discrimination complaints by including stupid text such as "Visually impaired users will require sighted assistance to ..." without providing accessible alternatives. When recently confronted with an application utilizing CAPTCHA that stated “Visually impaired users will require sighted assistance to …”, I asked a few technology security specialists about the efficacy of this technique. The comments were quite similar: “If the target is attractive enough, it is easy to outsource the breaking of it.”
Conclusion: don’t rely on CAPTCHA to protect attractive targets.
P.S. Don’t invite discrimination complaints by including stupid text such as “Visually impaired users will require sighted assistance to …” without providing accessible alternatives.

]]> By: Black Widow http://blackwidows.co.uk/blog/2007/10/06/breaking-captchas/#comment-46508 Black Widow Tue, 16 Oct 2007 19:20:48 +0000 http://blackwidows.co.uk/blog/?p=147#comment-46508 I have heard various stories about people solving captchas for rewards of one type or another but I've never come across a concrete example myself. Whilst it might be feasible, I do have to wonder whether it is an urban myth rather than a reality. I'd be very interested to hear of any documented cases. I have heard various stories about people solving captchas for rewards of one type or another but I’ve never come across a concrete example myself. Whilst it might be feasible, I do have to wonder whether it is an urban myth rather than a reality. I’d be very interested to hear of any documented cases.

]]> By: Richard Morton http://blackwidows.co.uk/blog/2007/10/06/breaking-captchas/#comment-46495 Richard Morton Tue, 16 Oct 2007 14:11:12 +0000 http://blackwidows.co.uk/blog/?p=147#comment-46495 What is also interesting is the problem whereby it is cheap enough to employ real humans to just enter the captchas thus negating any Turing test like solution. <a>QM Consulting Ltd</a> What is also interesting is the problem whereby it is cheap enough to employ real humans to just enter the captchas thus negating any Turing test like solution.

QM Consulting Ltd

]]> By: Smiffy http://blackwidows.co.uk/blog/2007/10/06/breaking-captchas/#comment-46432 Smiffy Mon, 15 Oct 2007 22:12:10 +0000 http://blackwidows.co.uk/blog/?p=147#comment-46432 The ability of software to pass this type of "Turing Test" is only half the problem; of more concern is the fact that human visitors can fail the test. So, with false positives <em>and</em> false negatives, just how much use is a technique? The ability of software to pass this type of “Turing Test” is only half the problem; of more concern is the fact that human visitors can fail the test. So, with false positives and false negatives, just how much use is a technique?

]]> By: Max Design - standards based web design, development and training » Some links for light reading (16/10/07) http://blackwidows.co.uk/blog/2007/10/06/breaking-captchas/#comment-46384 Max Design - standards based web design, development and training » Some links for light reading (16/10/07) Mon, 15 Oct 2007 14:32:46 +0000 http://blackwidows.co.uk/blog/?p=147#comment-46384 [...] Breaking CAPTCHAs [...] [...] Breaking CAPTCHAs [...]

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