Thursday, April 14, 2022

[SOLVED] Connect to SSH server through SOCKS5 proxy

Issue

how to connect via ssh using shared key with socks in python?

I have tested several ways, any suggestions?

Thank you very much in advance ...

Imports:

import paramiko
from paramiko import RSAKey
import socket
import socks
import base64

Script:

def createSSHClient(server, port, user):
    
    sock=socks.socksocket()
    sock.set_proxy(
        proxy_type=socks.SOCKS5,
        addr='10.0.0.2',
        port=1080,
        username=base64.b64decode('dXNlcg==').decode("utf-8"),
        password=base64.b64decode('cGFzc3dvcmQ=').decode("utf-8")
    )
             
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    privkey = paramiko.RSAKey.from_private_key_file('/home/my-user/.ssh/id_rsa')
    ssh.connect(server, port, user, privkey, sock)
    return ssh

outputsocks = []
ssh = createSSHClient('192.168.1.23', 22, 'my-user')
outputsocks.append((ssh.exec_command('ls -ltr')[1]).read().decode('ascii'))
ssh.close()

print(outputsocks)

Output:

Traceback (most recent call last):
  File "/home/my-user/teste2.py", line 26, in <module>
    ssh = createSSHClient('192.168.1.23', 22, 'my-user')
  File "/home/my-user/teste2.py", line 22, in createSSHClient
    ssh.connect(server, port, user, privkey, sock)
  File "/usr/local/lib/python3.6/site-packages/paramiko/client.py", line 349, in connect
    retry_on_signal(lambda: sock.connect(addr))
  File "/usr/local/lib/python3.6/site-packages/paramiko/util.py", line 283, in retry_on_signal
    return function()
  File "/usr/local/lib/python3.6/site-packages/paramiko/client.py", line 349, in <lambda>
    retry_on_signal(lambda: sock.connect(addr))
TimeoutError: [Errno 110] Connection timed out

Note: The same script works if you remove the connection via socks and use a host that does not need a VPN, the socks credentials are correct and the shared key works.


Solution

The error was in not opening the connection via sock before starting SSH, this was resolved with sock.connect()

More info: socket connect() vs bind()

Bug fix:

def createSSHClient(server, port, user):
    
    sock=socks.socksocket()
    sock.set_proxy(
        proxy_type=socks.SOCKS5,
        addr='10.0.0.2',
        port=1080,
        username=base64.b64decode('dXNlcg==').decode("utf-8"),
        password=base64.b64decode('cGFzc3dvcmQ=').decode("utf-8")
    )
    sock.connect(('192.168.1.20',22))
             
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    privkey = paramiko.RSAKey.from_private_key_file('/home/my-user/.ssh/id_rsa')
    ssh.connect(server, port, user, privkey, sock)
    return ssh

outputsocks = []
ssh = createSSHClient('192.168.1.23', 22, 'my-user')
outputsocks.append((ssh.exec_command('ls -ltr')[1]).read().decode('ascii'))
ssh.close()
sock.close()

print(outputsocks)


Answered By - Luis Henrique
Answer Checked By - David Marino (WPSolving Volunteer)
at