Creating Python SSHServer

Question

error message in terminalhelp I am trying to create an ssh server in python according to the book blackhat python, when I run this code I get "FileNotFoundError: [Errno 2] No such file or directory: '/home/burp/blackhatpy/.test_rsa.key'"

do I need to create the file .test_rsa.key? Help!! am a beginner and new to python, the image is what error i get When i try to run the server

import os
import paramiko
import socket
import sys
import threading

CWD = os.path.dirname(os.path.realpath(__file__))
HOSTKEY = paramiko.RSAKey(filename=os.path.join(CWD, '.test_rsa.key'))

class Server (paramiko.ServerInterface):
    def __init__(self):
        self.event = threading.Event()
        
    def check_channel_request(self, kind, chanid):
        if kind == 'session':
            return paramiko.OPEN_SUCCEEDED
        return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED
        
    def check_auth_password(self, username, password):
        if (username == 'tim') and (password == 'sekret'):
            return paramiko.AUTH_SUCCESSFUL
            
if __name__ == '__main__':
    server = '137.184.226.245'
    ssh_port = 2222
    try:
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.bind((server, ssh_port))
        sock.listen(100)
        print('[+] Listening for connection ...')
        client, addr = sock.accept()
    except Exception as e:
        print('[-] Listen failed: ' + str(e))
        sys.exit(1)
    else:
        print(f'[+] Got a connection! from {addr}')
        
    bhSession = paramiko.Transport(client)
    bhSession.add_server_key(HOSTKEY)
    server = Server()
    bhSession.start_server(server=server)
    
    chan = bhSession.accept(20)
    if chan is None:
        print('*** No channel.')
        sys.exit(1)
        
    print('[+] Authenticated!')
    print(chan.recv(1024).decode())
    chan.send('Welcome to bh_ssh')
    try:
        while True:
            command = input("Enter command: ")
            if command != 'exit':
                chan.send(command)
                r = chan.recv(8192)
                print(r.decode())
            else:
                chan.send('exit')
                print('exiting')
                bhSession.close()
                break
    except KeyboardInterrupt:
        bhSession.close()
            

Answer 1

In the book you refer to, where it presents the code that you've included here, it tells you where to get the SSH key file that should be used to run that code. It says:

For this example, we’re using the SSH key included in the Paramiko demo files.

That file can be found here:

https://github.com/paramiko/paramiko/blob/main/demos/test_rsa.key

The code you provide refers to a file with the name ".test_rsa.key". In the copy of the book that I have, the leading period (.) is not there. I only mention this in case you wonder why the file name in your version of the code is slightly different than that of the file I mention above.

Answer 2

Yes, you need to have that encryption key created before this. I am guessing, there must be a part to create the key, such as with ssh-keygen