Automating captcha protected forms

weedsmoker · Nov 1, 2011

I'm trying to submit form protected with captcha via python bot (using mechanize library).
Let's say i have 2 pages form.php and captcha.php. I grab the captcha image from captcha.php and manually solve it. But because captcha changes every reload, submitting fails because image retrieved from captcha.php isn't same as one in opened page where form is.
I found 2 possible solutions to save cookies from captcha.php and save it to browser instance of mechanize class and some vb.net solution where captcha.php is inserted in instance of webbrowser which opened form.php page.
I don't have a single clue how to implement this in python, and i don't see how can this solve the problem because captcha answer is stored in session variable on server.
I would like appreciate any hint on how to solve this problem in python or some other language.

weedsmoker · Mar 13, 2012

Well, i solved this some time ago, and today i remembered this thread i've started, so i'll post solution if someone has similar problem.

Code:

import cookielib
import mechanize
import urllib2

headers = [('Accept-Charset', 'ISO-8859-1,utf-8;q=0.7,*;q=0.7'), ('Connection', 'keep-alive'), ('Accept-Language', 'en-gb,en;q=0.5'), ('Accept', 'text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5'), ('User-Agent', 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)')]

html = urllib2.urlopen(form_url).read()

# your code to parse html and extract captcha url

req = urllib2.Request(captcha_url)
cj = cookielib.MozillaCookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
opener.addheaders = headers
urllib2.install_opener(opener)
cj.save('cookies.txt', ignore_discard=True, ignore_expires=True)

# your code to save captcha image or display captcha

cj = cookielib.MozillaCookieJar()
br = mechanize.Browser()
br.set_cookiejar(cj)
br.set_handle_redirect(True)
br.set_handle_referer(True)
br.set_handle_equiv(True)
br.set_handle_robots(False)
br.set_handle_refresh(mechanize._http.HTTPRefreshProcessor(), max_time=1)
br.addheaders = [('User-agent', 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)')]
br.open(form_url)
cj.load('cookies.txt', ignore_discard=True, ignore_expires=True)

# your mechanize code for form submitting

br.submit()

In this code 2 things are most important:
1. open captcha url and save cookies to cookies.txt file

Code:

cj.save('cookies.txt', ignore_discard=True, ignore_expires=True)

2. load cookies from cookies.txt after you opened form page

Code:

cj.load('cookies.txt', ignore_discard=True, ignore_expires=True)

different46 · Mar 13, 2012

thanks

Automating captcha protected forms

weedsmoker

Junior Member

weedsmoker

Junior Member

different46

Newbie

Main Menu

Marketplace

Making Money

BlackHat World