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Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

mediamemo.allthingsd.com

11–20 of 81 posts

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#12
post #5

I'll be happy with anything other than today's captcha solution. These are some captchas from my hall of fame: http://www.twitpic.com/2qbv0e/full

Those CAPTCHAs really aren't that bad. If I understand how ReCAPTCHA works, you only need to get one of the words correct.

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#13
post #3

So you replace the hard to read CAPTCHAs with easy to read ads. Of which presumably there will be a limited number in circulation at any one time. Sounds kinda easy to circumvent...

Indeed. Without some form of randomisation (which advertisers probably do not want), this would drastically lower the price of solving a captcha. Because you need to submit each ad to a human solver network only once, and can store the solution.

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#14
post #3

So you replace the hard to read CAPTCHAs with easy to read ads. Of which presumably there will be a limited number in circulation at any one time. Sounds kinda easy to circumvent...

A longtime standing solution to hard-to-read captchas are easy to read (but hard to process) captchas. E.g. show a picture of an animal or a shape and ask what it is, or even just ask a simple math problem or riddle in writing.

Problem with those are that they need to be constantly updated from a reliable source, or else, once the solution becomes popular, the spammer can bruteforce it in linear time (no matter how high N is, there are only N possible patterns).

This seems to be an attempt at fixing this. Ads are often relatively short lived so by the time the spammer has them bruteforced, it might be out of circulation - and more importantly, there are new ads in. It's an armsrace, and this is a way to pay our troops. Also, it's trivial for advertisers to make many different variations (e.g. one for each sales bulletpoint), so there are many variations in circulation. Since there's often more textual content than the password in the ad, they're not prone to simple OCR, while still easy to comprehend for the user.

Obvious shortcomings are if ads are not so shortlived, and if it's easy to identify and break classes of ads (e.g. if it's yellow and has the IE logo in position X, OCR area Y, done). Also, it's a bit of a dealbreaker if I'm forced to open and visit a website to get the password.

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#17
post #3

So you replace the hard to read CAPTCHAs with easy to read ads. Of which presumably there will be a limited number in circulation at any one time. Sounds kinda easy to circumvent...

You know, most modern capchas are not solved by bots, but by people in third world countries solving them for pennies. The current going rate is about $1/1000 and there are easy to use captcha solving APIs for any platform. capcha has long provided an illusion of security, nothing more. Any and all captchas will be broken.

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#18
post #17
post #3

So you replace the hard to read CAPTCHAs with easy to read ads. Of which presumably there will be a limited number in circulation at any one time. Sounds kinda easy to circumvent...

You know, most modern capchas are not solved by bots, but by people in third world countries solving them for pennies. The current going rate is about $1/1000 and there are easy to use captcha solving APIs for any platform. capcha has long provided an illusion of security, nothing more. Any and all captchas will be broken.

£1/1000 is still more expensive then if they could be done with human input. And they need to be done for every time a captcha is needed, with this scheme you could presumably pay for humans to solve the adds currently in rotation (ten? hundreds? thousands? not more than that) then just remember the results.

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#19
here is the challenge I got when I signed up for the service: http://imgur.com/x5hoN.png

for the solution I put in 'stupid', and it worked

this definitely doesn't solve the security considerations that captchas were designed for.

Update: Ok so it didn't take long to break this thing. These guys have the plain text of the CAPTCHA in the document DOM. It isn't even an image - the CAPTCHA is rendered in javascript. See: http://imgur.com/9VO4J.png

The 'brand' logos are an image, but they are simple to OCR.

So to break this CAPTCHA, simply hook v8 up to your auto-submit bot and interpret the JS that is being returned to you. You can't read it from the client because they serve that IFRAME from a diff domain - so they base their security on the browser x-domain policy. But that is all moot if you are building a bot, or if you build a browser extension that solves these things.

Re: Goodbye (Crummy) CAPTCHAs. Hello Ad Dollars?

#20
post #3

So you replace the hard to read CAPTCHAs with easy to read ads. Of which presumably there will be a limited number in circulation at any one time. Sounds kinda easy to circumvent...

A longtime standing solution to hard-to-read captchas are easy to read (but hard to process) captchas. E.g. show a picture of an animal or a shape and ask what it is, or even just ask a simple math problem or riddle in writing. Problem with those are that they need to be constantly updated from a reliable source, or else, once the solution becomes popular, the spammer can bruteforce it in linear time (no matter how h…

You have no idea what you're talking about.

> show a picture of an animal or a shape and ask what it is,

Ok, so let's say you come up with pictures of 20 different animals. A spam script that picks the same answer every time will have a 5% success rate.

> or even just ask a simple math problem or riddle in writing.

Computers are way better at solving most math problems than people.

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