Automate SSH login under windows

Question

I want to be able to execute openssh with some custom arguments and then be able to automatically login to the server. I want that my script will enter the password if needed and inject 'yes' if I'm prompted to add the fingerprint to the known hosts.

I've found SharpSsh for C# that do that, but I also need to use -D parameter and use ProxyCommand that I define in SSH, and the library is quite lacking for that usage.

Another thing that I've found was pexcept for Python that should do the trick but I couldn't find where to download it, on the offical page I'm being redirectred from sourceforge to some broken link.

Any help would be appreciated,

Bill.

nik · Answer 1 · 2009-07-20T13:56:21.823

9

If you use OpenSSH and then have a script to inject password in clear (meaning, you have stored the password unencrypted) it is defeating the purpose of secure shell.

Please strongly consider using public key mechanisms which can be easily and securely automated.

edited Jul 20 '09 at 13:56

answered Jun 16 '09 at 16:46

nik

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Bunk.... what makes pki more secure than passwords is it is impossible to guess a private key due to length and complexity of the string. but that is not an argument for not using passwords to automate logins. The only way password authentication in a script is less secure is if your box is compromised. In that case pki certs are just as vulnerable. This answer ignores the question. There are servers in top security situations which don't permit pki-certs because they don't permit anything being uploaded to the server. Bastion servers. In those cases only passwords are permitted! – JMS Aug 03 '23 at 14:45

score 3 · Answer 2 · answered Jun 16 '09 at 18:42

3

I'll second the recommendation to use public key authentication. Rather than hack around with expect, you might want to consider Paramiko - it's a native SSH client for Python which would greatly simplify the communications process, particularly if you ever need to interact with the remote server and it has support for things like SFTP built-in.

answered Jun 16 '09 at 18:42

Chris Adams

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I was also going to suggest Paramiko, but Chris beat me to it. – ShawnMilo Jul 20 '09 at 20:14
Too bad it doesn't have scp built-in. – Sep 17 '09 at 22:29
Noah: you want to use SFTP if at all possible as the scp "protocol" is ad-hoc. SFTP clients tend to interoperate a lot more consistently - not an issue if you're using OpenSSH everywhere but I've run into various problems with the commercial SSH servers – Chris Adams Sep 18 '09 at 18:02

score 2 · Answer 3 · answered Jun 16 '09 at 17:15

i use pexpect for similar purpose and download also work? http://sourceforge.net/project/downloading.php?group_id=59762&filename=pexpect-2.3.tar.gz

here is a portion fro my ssh automate script, you can customize it for you usage it may not run out of the box

import os
import getpass
import pexpect
import glob
import logging
import shutil
import time

class UpdateError(Exception): pass

g_password = None

def runSshCommand(cmd):
    global g_password

    ssh_newkey = 'Are you sure you want to continue connecting'
    # my ssh command line
    p=pexpect.spawn(cmd)

    i=p.expect([ssh_newkey,'password:',pexpect.EOF])
    if i==0:
        print "Saying yes to connection.."
        p.sendline('yes')
        i=p.expect([ssh_newkey,'password:',pexpect.EOF])

    if i==1:
        while True:
            if g_password is None:
                g_password = getpass.getpass("password:")
            p.sendline(g_password)
            i = p.expect(['password:',pexpect.EOF])
            if i==0:
                g_password = None
                print "Wrong password"
            else:
                break
    elif i==2:
        raise UpdateError("Got key or connection timeout")

    return p.before

score 1 · Answer 4 · answered Jun 16 '09 at 20:46

There is some excellent documentation on using Putty with generated SSH key authentication. This is an easy and secure way to accomplish your goals. Putty has a great set of features, for a windows SSH app. Even better when you consider that you can get it on the free.

score 0 · Answer 5 · edited Oct 20 '12 at 13:29

0

pexpect can't import on Windows. So, I use plink.exe with a Python subprocess to connect to the ssh server.

edited Oct 20 '12 at 13:29

jonsca

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answered Jun 28 '12 at 14:18

ihao

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score 0 · Answer 6 · answered Dec 04 '13 at 11:28

Another way is to to use openssh and establish a trusted key; if both client and the user account on the server have this key, then openssh does not request a password.

I have a script that automates setup of this - it works under cygwin,

http://mosermichael.github.io/cstuff/all/projects/2011/07/14/ssh-friends.html

score -1 · Answer 7 · answered Jun 16 '09 at 16:38

-1

I hope Net::SSH::Expect Perl module will be of help to you.

answered Jun 16 '09 at 16:38

Alan Haggai Alavi

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Automate SSH login under windows

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