netcat.py [ALPHA]

#
# Netcat
# Brett Stroud
# 01/20/2019
# v1.0
# netcat.py
#

import sys
import socket
import getopt
import threading
import subprocess

# Define global variables
listen          = False
command         = False
upload          = False
execute         = ""
target          = ""
upload_destination  = ""
port            = 0

def usage():
    print "BHP Net Tool"
    print
    print "Usage: bhpnet.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 connection upload a
                        file and write to [destination]"""
    print
    print
    print "Examples: "
    print "bhpnet.py -t 192.169.0.1 -p 5555 -1 -c"
    print "bhpnet.py -t 192.168.0.1 -p 5555 -1 -u=c:\\target.exe"
    print "bhpnet.py -t 192.168.0.1 -p 5555 -1 -e=\"cat /etc/passwd\""
    print "echo 'ABCDEFGHI' | ./bhpnet.py -t 192.168.11.12 -p 135"
    sys.exit(0)

def client_sender(buffer):

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

    try:
        # Attempt to establish connection with targeted host
        client.connect((target, port))

        if len(buffer):
            client.send(buffer)

        while True:

            # Await response
            recv_len = 1
            response = ""

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

                if recv_len < 4096:
                    break

        print response,

        # Await further input
        buffer = raw input("")
        buffer += "\n"

        # Send data
        client.send(buffer)

    except:

        print "[*] Exception detected! Exiting IMMEDIATELY."

        # Terminate the connection
        client.close()

def server_loop():
    global target
    # If a target is not specified LISTEN ON ALL INTERFACES
    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()

        # Create a new thread to process the incoming client
        client_thread = threading.Thread(target=client_handler,args=(client_socket,))
        client_thread.start()

def run_command(command):

    # Trim newline [newline = \n]
    command = command.rstrip()

    # Get output from STDOUT resulting from executing command
    try:
        ouput = subprocess.check_output(command,stderr=subprocess.STDOUT, shell=True)
    except:
        output = "[*]Command Failed to Execute!\r\n"

    # Return resulting output to the client
    return output

def client_handler(client_socket):
    global upload
    global execute
    global command

    # Run upload check
    if len(upload_destination):

        # Read in all bytes to memory and write to destination
        file_buffer = ""

        # Read data until nothing else is available
        while True:
            data = client_socket.recv(1024)

        if not data:
            break
        else:
            file_buffer += data

        # Attempt to write out the following bytes of data
        try:
            file_descriptor = open(upload_destination,"wb")
            file_descriptor.write(file_buffer)
            file_descriptor.close()

            # Confirm file was written out successfully
            client_socket.send("FILE WRITTEN TO: %s\r\n" % upload_destination)
        except:
            client_socket.send("FILE NOT WRITTEN TO: %s\r\n" % upload_destination)


    # Check for command execution
    if len(execute):

        # Run command
        output = run_command(execute)

        client_socket.send(output)


    # Enter secondary loop if command shell requested
    if command:

        while True:
            # Draw a simple prompt
            client_socket.send("<BHP:#> ")

                # Continue receiving until linefeed
                # is displayed (enter key)
            cmd_buffer = ""
            while "\n" not in cmd_buffer:
                cmd_buffer += client_socket.recv(1024)


            # Return the command output
            response = run_command(cmd_buffer)

            # Return the response
            client_socket.send(response)

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

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

    # Read the commandline options
    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"

    # Are we going to listen or just send data from stdin?
    if not listen and len(target) and port > 0:

        # Read in the buffer from the commandline
        # this will block, so send CTRL-D if not
        # sending input to stdin
        buffer = sys.stdin.read()

        # Send data off
        client_sender(buffer)

    # We are going to listen and potentially
    # upload things, execute commands, and drop a shell back
    # depending on our command line options above
    if listen:
        server_loop()

main()