captcha solver?

Discussion in 'Mac Programming' started by Gr3ml1n, May 1, 2016.

  1. Gr3ml1n macrumors newbie

    Joined:
    May 1, 2016
    #1
    I was wondering if someone could point me in the right direction to develop a program for mac that will solve captcha and auto input the letter. There will be a total of 9 letters to choose from.

    I want to open my browser, go to the captcha page, where my program would recognize the letters. Can someone point me in the right direction?
     
  2. Pakaku macrumors 68000

    Pakaku

    Joined:
    Aug 29, 2009
    #2
    Isn't the point of captchas to not be automatically solved?
     
  3. thewitt macrumors 68020

    thewitt

    Joined:
    Sep 13, 2011
    #3
    Yep...to prevent exactly what the OP is trying to do.
     
  4. TheAppleFairy macrumors 68020

    TheAppleFairy

    Joined:
    Mar 28, 2013
    Location:
    The Clinton Archipelago unfortunately
    #4
    Good luck, I can barely solve them half the time.
     
  5. teagls macrumors regular

    Joined:
    May 16, 2013
    #5
    I can give you some ideas/starting points. The best starting examples you will find use python. Essentially here is what you will do. Take the captcha from the website feed it into a python script that uses OpenCV with machine learning to recognize the letters. This is fairly straightforward and there are plenty of examples with OpenCV and python. Then have it dump out to you a string containing the letters/digits/text.

    Bypass Captcha using 10 lines of code with Python, OpenCV (I won't guarantee that this always works but it gives you a starting point)
    https://gist.github.com/chroman/5679049
     
  6. Toutou macrumors 6502a

    Toutou

    Joined:
    Jan 6, 2015
    Location:
    Prague, Czech Republic
    #6
    Have you ever wondered, like, what's the point of Captcha? :D
     
  7. MasConejos macrumors regular

    MasConejos

    Joined:
    Jun 25, 2007
    Location:
    Houston, TX
    #7
    Only somewhat related, there was a "voting" website once that let people cast a vote for something, up to one vote per minute. I was corralled into the voting by family, and after 30-60 minutes decided that this was really dumb, so I wrote a tiny webpage with a form with the key ids for what we were voting for, and set the page to refresh every minute, thereby casting my votes automatically.

    After some click-fraud (related to google ad words, not my thing) the admin added a captcha to every 5th vote that one cast. After studying the javascript for a bit I determined that the captcha was handled by a third party where the javascript would query if the captcha text was correct and the third party would respond yes or no. I made a new program in C# that would do an http post to submit the vote on a timer. If a captcha was required, my program would very helpfully inform the website that yes, I had indeed typed it correctly (I promise!).

    And thus the captcha was bypassed.

    Aftermath, for the curious:

    Somewhat amusingly, the web server powering this website was underpowered and would stop serving pages (http GET) for up to a few hours at a time. However, it would always process my program's incoming POSTs. So the website would go down and when it came back up our faction's votes would have jumped several hundred while the other faction's stayed the same. This caused all manner of chaos in the (very crazy, very rabid) user base. It remained entertaining for a few rounds of voting (each round lasted a week), and then I got bored with it and washed my hands of the whole mess.

    The site creator was a med student who's course load was picking up, and he basically dumped the site a month or two after the captcha update.

    Experimenting after everyone but about (literally) two users had abandoned the site, I determined that there was no validation for which voting period would accept votes. It was possible to log votes against a future period, and when that period finally arrived the voted for item would have a head start of however many votes had been cast.
     
  8. 960design macrumors 68020

    Joined:
    Apr 17, 2012
    Location:
    Destin, FL
    #8
    You can easily find many 'captcha bypass scripts' online. Adopt them to your needs. Not sure how sensitive MacRumors would be if I pointed you to a specific site for defeating captcha as it was/is used in their account creation process. Although their's could currently be bypassed with simple js. Captcha = novice level web development achievement.

    Captcha scripts have a better / higher / faster pass rate than I ( a human ) can.
     
  9. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #9
    The point of the captcha is to prevent what you're trying to do.

    The evolution is that there are programs out there that can actively solve letter recognition captchas so those are not the latest to be used now. Now I see a lot of the find the street sign or pictures of ATM, etc. If you can write a program that can solve the latter, you have just solved a major problem in machine learning...
     
  10. robvas macrumors 68020

    Joined:
    Mar 29, 2009
    Location:
    USA
    #10
    Any real captcha system is going to have a server-side check for it. Not that those can't be defeated in another way.

    Fun times to be had, captcha makers vs breakers :)
     
  11. teagls macrumors regular

    Joined:
    May 16, 2013
    #11
    I don't think you understand machine learning. Someone doesn't write a program to recognize a street sign. Using deep learning or something like a svm. Is an automated process. The algorithms use training examples to build a model. In the case of deep learning it works by passing an image through a neural net and generating weights at each neuron that best classify that particular example(this is a very high level explanation).

    Given enough examples you could very easily do what you described with deep learning it would be trivial. There are much much harder challenges in machine learning. These things include what activation function to use on each neuron. The best is currently ReLU. How best to handle gradient descent and the vanishing gradient in back propagation phase of training, minimizing the vc dimension to lower the amount of data required for training. Reducing the computation complexity. Deep learning is only possible with GPU computing.
     
  12. Belgique macrumors member

    Belgique

    Joined:
    May 6, 2016
    Location:
    Ocala, Floridah
    #12
    The point by geek developers is to drive us all CRAZY
     
  13. chrono1081 macrumors 604

    chrono1081

    Joined:
    Jan 26, 2008
    Location:
    Isla Nublar
    #13
    I remember reading something where captcha's were being bypassed by having the audio assistant used. It was easier to decipher the audio than the words.
     
  14. Mcmeowmers macrumors 6502

    Joined:
    Jun 1, 2015
    #14
    To prevent and/or stop spammers. An interesting application is reCAPTCHA where users help digitize articles!
     
  15. JustMartin macrumors 6502a

    Joined:
    Feb 28, 2012
    Location:
    UK
    #15
    Well, in one way that's already been done for quite a while. Automatic systems in the UK can take a photograph of your car, find the number plate - decode it and have a speeding fine in the post before you get home.
     
  16. mildocjr macrumors 65816

    #16
    you could always try a different attack vector the good ol'
    Code:
    12345' OR '1' = '1
     

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