I've been working on a bash script that automatically runs certain scripts on remote machines and saves the logs to certain folders. As of now I have been copying the local script to the remote machine, executing it into a remote log, copying the remote log into a local folder, and then deleting the remote log and remote copy of the script.
This works, but I know it can work better if I can avoid doing all the in between steps. The one caveat is I need this to be automatic and passwordless (meaning no user input at all). One of the scripts needs to be ran as root or it won't display all the necessary information and will userlock the machine temporarily.
The code I am currently using to execute the remoteScript into a log that I later retrieve with scp is below.
sshpass -f password.txt ssh user#1.1.1.1 "echo $password | sudo -S /home/user/remoteScript.sh > remoteLog.txt"
And in my testing, execution of local script on remote machine into local log file works like below
sshpass -f password.txt ssh user#1.1.1.1 "bash -s" < /home/user/localScript.sh >> localLog.txt
How could I combine the elements of the two code examples above in order to make a local script run on a remote machine with root privilege and log the output into a local text file?
Some things I have tried that do not work include:
sshpass -f password.txt ssh user#1.1.1.1 "bash -s" < "echo $password | sudo -S /home/user/script.sh >> log.txt"
sshpass -f password.txt ssh user#1.1.1.1 "echo $password | sudo -S /home/user/script.sh" >> log.txt
and notably
sshpass -f password.txt ssh user#1.1.1.1 echo $password | sudo -S /home/user/script.sh >> log.txt
which just executes the local script with root privilege on the local machine.
I have tried many variations of the above commands and I believe its some sort of piping or flow issue but I cannot figure it out. Is there anyway to do this?
Machines are Ubuntu 16.04 and you cannot ssh in already as root.
Thanks in advance
A) It might be worth looking into an orchestration/config management solution (e.g. ansible). It's a steep learning curve at first, but initial outlay will pay off on spades down the line if you're managing multiple servers.
B) Setup password-less sudo for the scripts you want to execute, so you don't have to pass around the password in plaintext, and can run without any input. In sudoers:
user ALL=(ALL) NOPASSWD:/home/user/script.sh
C) Setup an SSH key, so you don't need to use a password at all.
But in nutshell, the code you're looking for is something like:
cat /home/user/localScript.sh | ssh user#1.1.1.1 "sudo bash" > log.txt
Which executes a non-interactive bash shell as root on the remote machine, which will take commands to execute on standard in, and the standard output will come back over the ssh channel for you to write to your local log.
Look into &> or 2>&1 if you want standard error too.
I have a script which runs another script via SSH on a remote server using sudo. However, when I type the password, it shows up on the terminal. (Otherwise it works fine)
ssh user#server "sudo script"
What's the proper way to do this so I can type the password for sudo over SSH without the password appearing as I type?
Another way is to use the -t switch to ssh:
ssh -t user#server "sudo script"
See man ssh:
-t Force pseudo-tty allocation. This can be used to execute arbi-
trary screen-based programs on a remote machine, which can be
very useful, e.g., when implementing menu services. Multiple -t
options force tty allocation, even if ssh has no local tty.
I was able to fully automate it with the following command:
echo pass | ssh -tt user#server "sudo script"
Advantages:
no password prompt
won't show password in remote machine bash history
Regarding security: as Kurt said, running this command will show your password on your local bash history, and it's better to save the password in a different file or save the all command in a .sh file and execute it. NOTE: The file need to have the correct permissions so that only the allowed users can access it.
Sudo over SSH passing a password, no tty required:
You can use sudo over ssh without forcing ssh to have a pseudo-tty (without the use of the ssh "-t" switch) by telling sudo not to require an interactive password and to just grab the password off stdin. You do this by using the "-S" switch on sudo. This makes sudo listen for the password on stdin, and stop listening when it sees a newline.
Example 1 - Simple Remote Command
In this example, we send a simple whoami command:
$ ssh user#server cat \| sudo --prompt="" -S -- whoami << EOF
> <remote_sudo_password>
root
We're telling sudo not to issue a prompt, and to take its input from stdin. This makes the sudo password passing completely silent so the only response you get back is the output from whoami.
This technique has the benefit of allowing you to run programs through sudo over ssh that themselves require stdin input. This is because sudo is consuming the password over the first line of stdin, then letting whatever program it runs continue to grab stdin.
Example 2 - Remote Command That Requires Its Own stdin
In the following example, the remote command "cat" is executed through sudo, and we are providing some extra lines through stdin for the remote cat to display.
$ ssh user#server cat \| sudo --prompt="" -S -- "cat" << EOF
> <remote_sudo_password>
> Extra line1
> Extra line2
> EOF
Extra line1
Extra line2
The output demonstrates that the <remote_sudo_password> line is being consumed by sudo, and that the remotely executed cat is then displaying the extra lines.
An example of where this would be beneficial is if you want to use ssh to pass a password to a privileged command without using the command line. Say, if you want to mount a remote encrypted container over ssh.
Example 3 - Mounting a Remote VeraCrypt Container
In this example script, we are remotely mounting a VeraCrypt container through sudo without any extra prompting text:
#!/bin/sh
ssh user#server cat \| sudo --prompt="" -S -- "veracrypt --non-interactive --stdin --keyfiles=/path/to/test.key /path/to/test.img /mnt/mountpoint" << EOF
SudoPassword
VeraCryptContainerPassword
EOF
It should be noted that in all the command-line examples above (everything except the script) the << EOF construct on the command line will cause the everything typed, including the password, to be recorded in the local machine's .bash_history. It is therefore highly recommended that for real-world use you either use do it entirely through a script, like the veracrypt example above, or, if on the command line then put the password in a file and redirect that file through ssh.
Example 1a - Example 1 Without Local Command-Line Password
The first example would thus become:
$ cat text_file_with_sudo_password | ssh user#server cat \| sudo --prompt="" -S -- whoami
root
Example 2a - Example 2 Without Local Command-Line Password
and the second example would become:
$ cat text_file_with_sudo_password - << EOF | ssh va1der.net cat \| sudo --prompt="" -S -- cat
> Extra line1
> Extra line2
> EOF
Extra line1
Extra line2
Putting the password in a separate file is unnecessary if you are putting the whole thing in a script, since the contents of scripts do not end up in your history. It still may be useful, though, in case you want to allow users who should not see the password to execute the script.
Assuming you want no password prompt:
ssh $HOST 'echo $PASSWORD | sudo -S $COMMMAND'
Example
ssh me#localhost 'echo secret | sudo -S echo hi' # outputs 'hi'
The best way is ssh -t user#server "sudo <scriptname>", for example ssh -t user#server "sudo reboot".
It will prompt for password for user first and then root(since we are running the script or command with root privilege.
I hope it helped and cleared your doubt.
NOPASS in the configuration on your target machine is the solution. Continue reading at http://maestric.com/doc/unix/ubuntu_sudo_without_password
echo $VAR_REMOTEROOTPASS | ssh -tt -i $PATH_TO_KEY/id_mykey $VAR_REMOTEUSER#$varRemoteHost
echo \"$varCommand\" | sudo bash
confirming that the answer of #ofirule is working like a charm.
I try ot even with sshpass & it works. This is how to use it with sshpass:
echo $pass | sshpass -p $pass ssh -tt cloud_user#$ip "sudo su -"
you will find yourself in the root shell directly
Ok, I have been searching for few hours and cannot seem to find the solution.
I have a file on a remote server to which one of the local users on that server has write access. I have the credentials. The requirement is:
The shell/perl script should automatically login to the server and write to that file.
The script should work from any server on the network without installing any extra packages as that will require me to sudo which will again ask for password and is therefore not possible from script.
I tried using expect but the server keeps saying spawn not found.
Please advise.
#!/bin/bash
ssh -l username hostname "password; ~/updatefile.sh params"
Doesn't work.
To use the key method, try the following:
#!/usr/bin/env ssh-agent /usr/bin/env bash
KEYFILE=`mktemp`
cat << EOF > ${KEYFILE}
-----BEGIN RSA PRIVATE KEY-----
[.......]
EOF
ssh-add ${KEYFILE}
ssh user host command
# Remove the key file.
rm -f ${KEYFILE}
To generate a key for use, refer to the following: http://www.ece.uci.edu/~chou/ssh-key.html
I have an FTP script running on Linux and it is failing. Here is the script:
/usr/bin/ftp -v -i -n my.ftp.server << cmd
user ftpuser password
binary
ls
<some other commands here>
quit cmd
It returns an error:
421 Service not available, remote server has closed connection
Not connected.
The weird thing here is that if I just typed this in the command line:
/usr/bin/ftp my.ftp.server
It asks for a username and password and after I supplied them, I was able to connect!
In ftp> I type ls and I can see the files from the FTP server.
What is wrong with my script?
And also, I don't have putty access to the FTP server so I can't see the logs from there. Any ideas?
Thanks!
Here is an example of a correct ftp linux script.
#!/bin/sh
HOST='ftp.server.com'
USER='user'
PASSWD='pw'
FILE='file.txt' #sample file to upload
ftp -n $HOST <<END_SCRIPT
quote USER $USER
quote PASS $PASSWD
put $FILE #sample command
#some other commands here
quit
END_SCRIPT
exit 0
#!/bin/csh
ssh -o StrictHostKeyChecking=no xyz123#remotemachine.com
sudo -su rootuser
ksh
. /mydir/setup_env.ksh
ls -ltr
Above is the list of task i need to do.
Login into remote machine without password prompt
Run Sudo to get access to Root
Change shell to ksh
execute a script (setup_env.ksh)
List files using ls -ltr
When i execute this script from , lets say localunixmachine.com...
It ask me for password
once i enter password , it will transfer to remote machine but wont execute remaining commands
If i exit from remote session, it will execute remaining command.
Can you please Guide me whats the best way to accomplish what i am trying here.
first you can copy your ssh public key which you can generate ssh-keygen to authorized_keys to the remote server root/.ssh/authorized_keys
and then the script will be
ssh root#remotemachine.com "/bin/ksh mydir/setup_env.ksh"
I think this should work for executing multiple commands remotely:
#!/bin/bash
ssh -o StrictHostKeyChecking=no xyz123#remotemachine.com <<EOF
sudo -su rootuser
ksh
. /mydir/setup_env.ksh
ls -ltr
EOF
As for login to the server without password, you need to setup ssh authentication with keys.