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Changing password of a remote Linux system using Python (sftp)

It seems very simple, but I searched multiple resources but could not find an answer on how to change a remote Linux system password using Python and with SFTP.
def changepwd():
sftp_client = ssh.open_sftp()
#change password of root on remote server
Are there any built-in modules that I can use to change the password?
Thanks in advance.
Thanks for all you help. This is how I changed the passwd for 'root'.
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(hostname, username=Name, password=Pwd)
print "Connection succesfully established ...with %s " % hostname
stdin, stdout, stderr = ssh.exec_command('echo -e "newpasswd\newPasswd" | passwd')
print "stderr: ", stderr.readlines()
print "pwd: ", stdout.readlines()
ssh.close()

You cannot change password with SFTP protocol.
You can change password with SSH protocol. But the SSH protocol API for changing a password is not support by the most widespread SSH server – OpenSSH. Nor it is supported by the most widespread Python SSH library – Paramiko. So this most likely won't work for you anyway.
So in the end the only viable option is to execute a relevant shell command (passwd or chpasswd) via SSH (e.g. using Paramiko).

How to SSH from one system to another using python

I am trying to perform SSH from one system to another using paramiko in python
import paramiko
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(
paramiko.AutoAddPolicy())
ssh.connect('127.0.0.1', username='jesse',
password='lol')
using this reference (http://jessenoller.com/blog/2009/02/05/ssh-programming-with-paramiko-completely-different )
This is the case when we know the password of the system you want to log-in BUT
if i want to login to a system where my public-key is copied and i dont know the password. Is there a way to do this
Thanks in advance

SSHClient.connect accepts a kwarg key_filename, which is a path to the local private key file (or files, if given a list of paths). See the docs.
key_filename (str) – the filename, or list of filenames, of optional private key(s) to try for authentication
Usage:
ssh.connect('<hostname>', username='<username>', key_filename='<path/to/openssh-private-key-file>')

This code should work:
import paramiko
host = "<your-host>"
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect(host, username='<your-username>', key_filename="/path/to/.ssh/id_rsa" , port=22)
# Just to test a command
stdin, stdout, stderr = client.exec_command('ls')
for line in stdout.readlines():
print line
client.close()
Here is the documentation of SSHClient.connect()
EDIT : /path/to/.ssh/id_rsa is your private key!

Adding the key to a configured SSH agent would make paramiko use it automatically with no changes to your code.
ssh-add <your private key>
Your code will work as is. Alternatively, the private key can be provided programmatically with
key = paramiko.RSAKey.from_private_key_file(<filename>)
SSHClient.connect(pkey=key)

Subprocess on remote server

I am using this code for executing command on remote server.
import subprocess
import sys
COMMAND="ls"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
When I try to execute this script, I get prompt for password. Is there any way I could avoid it, for example, can I enter password in script somehow? Also, password should be encrypted somehow so that people who have access to the script cannot see it.

Why make it so complicated? Here's what I suggest:
1) Create a ssh config section in your ~/.ssh/config file:
Host myserver
HostName 50.50.50.12 (fill in with your server's ip)
Port xxxx (optional)
User me (your username for server)
2) If you have generated your ssh keypair do it now (with ssh-keygen). Then upload with:
$ ssh-copy-id myserver
3) Now you can use subprocess with ssh. For example, to capture output, I call:
result = subprocess.check_output(['ssh', 'myserver', 'cat', 'somefile'])
Simple, robust, and the only time a password is needed is when you copy the public key to the server.
BTW, you code will probably work just fine as well using these steps.

One way is to create a public key, put it on the server, and do ssh -i /path/to/pub/key user#host or use paramiko like this:
import paramiko
import getpass
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
p = getpass.getpass()
ssh.connect('hostname', username='user', password=p)
stdin, stdout, stderr = ssh.exec_command('ls')
print stdout.readlines()
ssh.close()

You should use pexpect or paramiko to connect to remote machine,then spawn a child ,and then run subprocess to achieve what you want.

Here's what I did when encountering this issue before:
Set up your ssh keys for access to the server.
Set up an alias for the server you're accessing. Below I'll call it remote_server.
Put the following two lines at the end of ~/.bash_profile.
eval $(ssh-agent -s)
ssh-add
Now every time you start your shell, you will be prompted for a passphrase. By entering it, you will authenticate your ssh keys and put them 'in hand' at the start of your bash session. For the remainder of your session you will be able to run commands like
ssh remote_server ls
without being prompted for a passphrase. Here ls will run on the remote server and return the results to you. Likewise your python script should run without password prompt interruption if you execute it from the shell.
You'll also be able to ssh to the server just by typing ssh remote_server without having to enter your username or password every time.
The upside to doing it this way is that you should be doing this anyway to avoid password annoyances and remembering funky server names :) Also you don't have to worry about having passwords saved anywhere in your script. The only potential downside is that if you want to share the python script with others, they'll have to do this configuring as well (which they should anyway).

You don't really need something like pexpect to handle this. SSH keys already provide a very good and secure solution to this sort of issue.
The simplest way to get the results you want would probably be to generate an ssh key and place it in the .ssh folder of your device. I believe github has a pretty good guide to doing that, if you look into it. Once you set up the keys correctly on both systems, you won't actually have to add a single line to your code. When you don't specify a password it will automatically use the key to authenticate you.

While subprocess.Popen might work for wrapping ssh access, this is not the preferred way to do so.
I recommend using paramiko.
import paramiko
ssh_client = paramiko.SSHClient()
ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh_client.connect(server, username=user,password=password)
...
ssh_client.close()
And If you want to simulate a terminal, as if a user was typing:
chan=ssh_client.invoke_shell()
def exec_cmd(cmd):
"""Gets ssh command(s), execute them, and returns the output"""
prompt='bash $' # the command line prompt in the ssh terminal
buff=''
chan.send(str(cmd)+'\n')
while not chan.recv_ready():
time.sleep(1)
while not buff.endswith(prompt):
buff+=ssh_client.chan.recv(1024)
return buff[:len(prompt)]
Example usage: exec_cmd('pwd')
If you don't know the prompt in advance, you can set it with:
chan.send('PS1="python-ssh:"\n')

You could use following.
import subprocess
import sys
COMMAND="ls"
ssh = subprocess.Popen("powershell putty.exe user#HOST -pw "password", stdout=PIPE, stdin=PIPE, stderr=STDOUT)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result

Sending a password over SSH or SCP with subprocess.Popen

I'm trying to run an scp (secure copy) command using subprocess.Popen. The login requires that I send a password:
from subprocess import Popen, PIPE
proc = Popen(['scp', "user#10.0.1.12:/foo/bar/somefile.txt", "."], stdin = PIPE)
proc.stdin.write(b'mypassword')
proc.stdin.flush()
This immediately returns an error:
user#10.0.1.12's password:
Permission denied, please try again.
I'm certain the password is correct. I easily verify it by manually invoking scp on the shell. So why doesn't this work?
Note, there are many similar questions to this, asking about subprocess.Popen and sending a password for automated SSH or FTP login:
How can I set a users password in linux from a python script?
Use subprocess to send a password
The answer(s) to these questions don't work and/or don't apply because I am using Python 3.

Here's a function to ssh with a password using pexpect:
import pexpect
import tempfile
def ssh(host, cmd, user, password, timeout=30, bg_run=False):
"""SSH'es to a host using the supplied credentials and executes a command.
Throws an exception if the command doesn't return 0.
bgrun: run command in the background"""
fname = tempfile.mktemp()
fout = open(fname, 'w')
options = '-q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null -oPubkeyAuthentication=no'
if bg_run:
options += ' -f'
ssh_cmd = 'ssh %s#%s %s "%s"' % (user, host, options, cmd)
child = pexpect.spawn(ssh_cmd, timeout=timeout) #spawnu for Python 3
child.expect(['[pP]assword: '])
child.sendline(password)
child.logfile = fout
child.expect(pexpect.EOF)
child.close()
fout.close()
fin = open(fname, 'r')
stdout = fin.read()
fin.close()
if 0 != child.exitstatus:
raise Exception(stdout)
return stdout
Something similar should be possible using scp.

The OpenSSH scp utility invokes the ssh program to make the SSH connection to the remote host, and the ssh process handles authentication. The ssh utility doesn't accept a password on the command line or on its standard input. I believe this is a deliberate decision on the part of the OpenSSH developers, because they feel that people should be using more secure mechanisms like key-based authentication. Any solution for invoking ssh is going to follow one of these approaches:
Use an SSH key for authentication, instead of a password.
Use sshpass, expect, or a similar tool to automate responding to the password prompt.
Use (abuse) the SSH_ASKPASS feature to get ssh to get the password by invoking another command, described here or here, or in some of the answers here.
Get the SSH server administrator to enable host-based authentication and use that. Note that host-based authentication is only suitable for certain network environments. See additional notes here and here.
Write your own ssh client using perl, python, java, or your favorite language. There are ssh client libraries available for most modern programming languages, and you'd have full control over how the client gets the password.
Download the ssh source code and build a modified version of ssh that works the way you want.
Use a different ssh client. There are other ssh clients available, both free and commercial. One of them might suit your needs better than the OpenSSH client.
In this particular case, given that you're already invoking scp from a python script, it seems that one of these would be the most reasonable approach:
Use pexpect, the python expect module, to invoke scp and feed the password to it.
Use paramiko, the python ssh implementation, to do this ssh task instead of invoking an outside program.

The second answer you linked suggests you use Pexpect (which is usually the right way to go about interacting with command line programs that expect input).

Pexpect has a library for exactly this: pxssh
http://pexpect.readthedocs.org/en/stable/api/pxssh.html
import pxssh
import getpass
try:
s = pxssh.pxssh()
hostname = raw_input('hostname: ')
username = raw_input('username: ')
password = getpass.getpass('password: ')
s.login(hostname, username, password)
s.sendline('uptime') # run a command
s.prompt() # match the prompt
print(s.before) # print everything before the prompt.
s.logout()
except pxssh.ExceptionPxssh as e:
print("pxssh failed on login.")
print(e)

I guess some applications interact with the user using stdin and some applications interact using terminal. In this case when we write the password using PIPE we are writing to stdin. But SCP application reads the password from terminal. As subprocess cannot interact with user using terminal but can only interact using stdin we cannot use the subprocess module and we must use pexpect for copying the file using scp.
Feel free for corrections.

Here is my scp function based on pexpect. It can handle wildcards (i.e. multiple file transfer), in addition to the password.
To handle multiple file transfer (i.e. wildcards), we need to issue a command via a shell. Refer to pexpect FAQ.
import pexpect
def scp(src,user2,host2,tgt,pwd,opts='',timeout=30):
''' Performs the scp command. Transfers file(s) from local host to remote host '''
cmd = f'''/bin/bash -c "scp {opts} {src} {user2}#{host2}:{tgt}"'''
print("Executing the following cmd:",cmd,sep='\n')
tmpFl = '/tmp/scp.log'
fp = open(tmpFl,'wb')
childP = pexpect.spawn(cmd,timeout=timeout)
try:
childP.sendline(cmd)
childP.expect([f"{user2}#{host2}'s password:"])
childP.sendline(pwd)
childP.logfile = fp
childP.expect(pexpect.EOF)
childP.close()
fp.close()
fp = open(tmpFl,'r')
stdout = fp.read()
fp.close()
if childP.exitstatus != 0:
raise Exception(stdout)
except KeyboardInterrupt:
childP.close()
fp.close()
return
print(stdout)
It can be used this way:
params = {
'src': '/home/src/*.txt',
'user2': 'userName',
'host2': '192.168.1.300',
'tgt': '/home/userName/',
'pwd': myPwd(),
'opts': '',
}
scp(**params)

This is a rewrite I did from the code posted by #Kobayashi and #sjbx but for the purposes of doing scp requests, so credit to those two.
def scp(host, user, password, from_dir, to_dir, timeout=300, recursive=False):
fname = tempfile.mktemp()
fout = open(fname, 'w')
scp_cmd = 'scp'
if recursive:
scp_cmd += ' -r'
scp_cmd += f' {user}#{host}:{from_dir} {to_dir}'
child = pexpect.spawnu(scp_cmd, timeout=timeout)
child.expect(['[pP]assword: '])
child.sendline(str(password))
child.logfile = fout
child.expect(pexpect.EOF)
child.close()
fout.close()
fin = open(fname, 'r')
stdout = fin.read()
fin.close()
if 0 != child.exitstatus:
raise Exception(stdout)
return stdout

How to create a SSH tunnel using Python and Paramiko?

I need to create tunneling to read information from a database. I use Paramiko, but I have not worked with tunneling yet. Please provide an example of a simple code that creates and closes a tunnel.

At work we usually create ssh tunnels forwarding ports. The way we do that is, by using the standard command ssh -L port:addr:port addr with subprocess running in a separate thread.
I found this useful link: https://github.com/paramiko/paramiko/blob/master/demos/forward.py with an example of doing port forwarding with paramiko.

I used sshtunnel for my projects. Example of the forwarding remote local MySQL port to the host local port:
pip install sshtunnel
python -m sshtunnel -U root -P password -L :3306 -R 127.0.0.1:3306 -p 2222 localhost

Even though this does not use paramiko, I believe it's a very clean solution to implement (similar to #dario's answer but without managing the thread in python).
There's this little-mentioned feature in openssh client that allows us to control a ssh process through a unix socket, quoting man ssh:
-M Places the ssh client into “master” mode for connection sharing. Multiple -M options places ssh
into “master” mode with confirmation required before slave connections are accepted. Refer to the
description of ControlMaster in ssh_config(5) for details.
-S ctl_path
Specifies the location of a control socket for connection sharing, or the string “none” to disable
connection sharing. Refer to the description of ControlPath and ControlMaster in ssh_config(5)
for details.
So you can start background process of ssh (with -Nf) and then check (or terminate) it with a another ssh call.
I use this in a project that requires a reverse tunnel to be established
from subprocess import call, STDOUT
import os
DEVNULL = open(os.devnull, 'wb')
CONFIG = dict(
SSH_SERVER='ssh.server.com',
SSH_PORT=2222,
SSH_USER='myuser',
SSH_KEY='/path/to/user.key',
REMOTE_PORT=62222,
UNIX_SOCKET='/tmp/ssh_tunnel.sock',
KNOWN_HOSTS='/path/to/specific_known_host_to_conflicts',
)
def start():
return call(
[
'ssh', CONFIG['SSH_SERVER'],
'-Nfi', CONFIG['SSH_KEY'],
'-MS', CONFIG['UNIX_SOCKET'],
'-o', 'UserKnownHostsFile=%s' % CONFIG['KNOWN_HOSTS'],
'-o', 'ExitOnForwardFailure=yes',
'-p', str(CONFIG['SSH_PORT']),
'-l', CONFIG['SSH_USER'],
'-R', '%d:localhost:22' % CONFIG['REMOTE_PORT']
],
stdout=DEVNULL,
stderr=STDOUT
) == 0
def stop():
return __control_ssh('exit') == 0
def status():
return __control_ssh('check') == 0
def __control_ssh(command):
return call(
['ssh', '-S', CONFIG['UNIX_SOCKET'], '-O', command, 'x'],
stdout=DEVNULL,
stderr=STDOUT
)
-o ExitOnForwardFailure=yes makes sure the ssh command will fail if the tunnel cannot be established, otherwise it will not exit.

Might I suggest trying something like pyngrok to programmatically manage an ngrok tunnel for you? Full disclosure, I am the developer of it. SSH example here, but it's as easy as installing pyngrok:
pip install pyngrok
and using it:
from pyngrok import ngrok
# <NgrokTunnel: "tcp://0.tcp.ngrok.io:12345" -> "localhost:22">
ssh_tunnel = ngrok.connect(22, "tcp")

I used paramiko for some project I had a year ago, here is the part of my code where I connected with another computer/server and executed a simple python file:
import paramiko
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(hostname='...', username='...', password='...')
stdin, stdout, stderr = ssh.exec_command('python hello.py')
ssh.close()
stdin, stdout and sdterr contain the inputs/outputs of the command you executed.
From here, I think you can make the connection with the database.
Here is some good information about paramiko.