How to get root access after ssh in a script? [duplicate] - linux

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

Related

Passwordless execution of local script on remote machine as root into a local file

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.

How to sudo run a local script over ssh

I try to sudo run a local script over ssh,
ssh $HOST < script.sh
and I tried
ssh -t $HOST "sudo -s && bash" < script.sh
Actually, I searched a lot in google, find some similar questions, however, I don't find a solution which can sudo run a local script.
Reading the error message of
$ ssh -t $HOST "sudo -s && bash" < script.sh
Pseudo-terminal will not be allocated because stdin is not a terminal.
makes it pretty clear what's going wrong here.
You can't use the ssh parameter -t (which sudo needs to ask for a password) whilst redirecting your script to bash's stdin of your remote session.
If it is acceptable for you, you could transfer the local script via scp to your remote machine and then execute the script without the need of I/O redirection:
scp script.sh $HOST:/tmp/ && ssh -t $HOST "sudo -s bash /tmp/script.sh"
Another way to fix your issue is to use sudo in non-interactive mode -n but for this you need to set NOPASSWD within the remote machine's sudoers file for the executing user. Then you can use
ssh $HOST "sudo -n -s bash" < script.sh
To make Edward Itrich's answer more scalable and geared towards frequent use, you can set up a system where you only run a one line script that can be quickly ported to any host, file or command in the following manner:
Create a script in your Scripts directory if you have one by changing the name you want the script to be (I use this format frequently to change 1 word for my script name and create the file, set permissions and open for editing):
newscript="runlocalscriptonremotehost.sh"
touch $newscript && chmod +x $newscript && nano $newscript
In nano fill out the script as follows placing the directory and name information of the script you want to run remotely in the variable lines of runlocalscriptonremotehost.sh(only need to edit lines 1-3):
HOSTtoCONTROL="sudoadmin#192.168.0.254"
PATHtoSCRIPT="/home/username/Scripts/"
SCRIPTname="scripttorunremotely.sh"
scp $PATHtoSCRIPT$SCRIPTname $HOSTtoCONTROL:/tmp/ && ssh -t $HOSTtoCONTROL "sudo -s bash /tmp/$SCRIPTname"
Then just run:
sh ./runlocalscriptonremotehost.sh
Keep runlocalscriptonremotehost.sh open in a tabbed text editor for quick updating, go ahead and create a bash alias for the script and you have yourself an app-ified version of this frequently used operation.
First of all divide your objective in 2 parts. 1) ssh to the host. 2) run the command you want as sudo. After you are certain that you can 1) access the host and 2) have sudo privileges then you can combine the two commands with &&. What x_cmd && y_cmd does is that the y_cmd gets executed after x_cmd has exited successfully.

How do you keep the password hidden when invoked during the su command?

This is the first time it has happened to me where I am using the su command and it actually displays the password on the terminal and doesn't stay hidden. Here is my code snippet:
sshpass -p "password" ssh -q username#74.11.11.11 "su -lc 'mkdir temp/'"
Code explanation: I am accessing a remote server and trying be root on that server to create a folder. In doing so I have to use the su command and it prompts me for the password. When I enter the password, it gets displayed and doesn't stay hidden. How do I fix that?
The solution is to allocate a pseudo TTY (using the -t option on ssh):
sshpass -p "password" ssh -t -q username#74.11.11.11 "su -lc 'mkdir temp/'"
Without this, there's no "terminal" in this context and su is unable to disable echo of the password.
Just like I replied to you here.
It's possible to keep it "hidden" from the command line:
Edit your /etc/profile and paste there:
export SSHPASS='my_pass_here'
Use the -e argument with sshpass command
$ sshpass -e ssh usernmane#hosting.example 'ls -ll'
Another option is to save your password in a different file and use the -f argument:
$ sshpass -f password_filename ssh usernmane#hosting.example 'ls -la'
But the best solution is to follow the #Hristo Mohamed suggestion:
In general please AVOID using sshpass with a password.
You can set up easily a generate ssh key just to do this job and then remove it.

How to run sudo under su?

I have this:
su $username -c ./script.sh
The problem is that within script I have 'sudo' commands and they says me
sudo: no tty present and no askpass program specified
How to do this right?
UPD: I need both sudo and su. What I need to do is run script as USER $username and be able to run certain commands within script as root (for example, pacman -S)
SOLUTION: I've added NOPASSWD option to /etc/sudoers before running script and delete this entry using sed after script finished.
First set chmod +x to your scripts
try:
#!/bin/bash
echo "hello"
su - <your-user> -c /path/to/script.sh
echo "good bye"
UPDATE:
You should find a way to force bash to use pseudo-tty
Force pseudo-tty allocation. This can be used to execute arbitrary 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.
If the user is not as sudoers do the following steps:
This is what you need to do in /etc/sudoers:
# User privilege specification
root ALL=(ALL:ALL) ALL
newuser ALL=(ALL:ALL) ALL
you have also ways to do:
you can pipe password if it has password:
echo "yourpassword" | sudo -S
OR
You can run the following script:
#!/usr/bin/expect -f
spawn sudo -s <<EOF
expect "assword for username:"
send -- "user-password\r"
expect eof
Also you can do that:
sudo -kS bash - << EOF
password
whoami
echo "Not a good idea to have a password encoded in plain text"
EOF

How to pass the password to su/sudo/ssh without overriding the TTY?

I'm writing a C Shell program that will be doing su or sudo or ssh. They all want their passwords in console input (the TTY) rather than stdin or the command line.
Does anybody know a solution?
Setting up password-less sudo is not an option.
expect could be an option, but it's not present on my stripped-down system.
For sudo there is a -S option for accepting the password from standard input. Here is the man entry:
-S The -S (stdin) option causes sudo to read the password from
the standard input instead of the terminal device.
This will allow you to run a command like:
echo myPassword | sudo -S ls /tmp
As for ssh, I have made many attempts to automate/script it's usage with no success. There doesn't seem to be any build-in way to pass the password into the command without prompting. As others have mentioned, the "expect" utility seems like it is aimed at addressing this dilemma but ultimately, setting up the correct private-key authorization is the correct way to go when attempting to automate this.
I wrote some Applescript which prompts for a password via a dialog box and then builds a custom bash command, like this:
echo <password> | sudo -S <command>
I'm not sure if this helps.
It'd be nice if sudo accepted a pre-encrypted password, so I could encrypt it within my script and not worry about echoing clear text passwords around. However this works for me and my situation.
For ssh you can use sshpass: sshpass -p yourpassphrase ssh user#host.
You just need to download sshpass first :)
$ apt-get install sshpass
$ sshpass -p 'password' ssh username#server
For sudo you can do this too:
sudo -S <<< "password" command
I've got:
ssh user#host bash -c "echo mypass | sudo -S mycommand"
Works for me.
The usual solution to this problem is setuiding a helper app that performs the task requiring superuser access:
http://en.wikipedia.org/wiki/Setuid
Sudo is not meant to be used offline.
Later edit: SSH can be used with private-public key authentication. If the private key does not have a passphrase, ssh can be used without prompting for a password.
Maybe you can use an expect command?:
expect -c 'spawn ssh root#your-domain.com;expect password;send "your-password\n";interact
That command gives the password automatically.
This can be done by setting up public/private keys on the target hosts you will be connecting to.
The first step would be to generate an ssh key for the user running the script on the local host, by executing:
ssh-keygen
Enter file in which to save the key (/home/myuser/.ssh/id_rsa): <Hit enter for default>
Overwrite (y/n)? y
Then enter a blank password. After that, copy your ssh key onto the target host which you will be connecting to.
ssh-copy-id <remote_user>#<other_host>
remote_user#other_host's password: <Enter remote user's password here>
After registering the ssh keys, you would be able to perform a silent ssh remote_user#other_host from you local host.
When there's no better choice (as suggested by others), then man socat can help:
(sleep 5; echo PASSWORD; sleep 5; echo ls; sleep 1) |
socat - EXEC:'ssh -l user server',pty,setsid,ctty
EXEC’utes an ssh session to server. Uses a pty for communication
between socat and ssh, makes it ssh’s controlling tty (ctty),
and makes this pty the owner of a new process group (setsid), so
ssh accepts the password from socat.
All of the pty,setsid,ctty complexity is necessary and, while you might not need to sleep as long, you will need to sleep. The echo=0 option is worth a look too, as is passing the remote command on ssh's command line.
Take a look at expect linux utility.
It allows you to send output to stdio based on simple pattern matching on stdin.
ssh -t -t me#myserver.io << EOF
echo SOMEPASSWORD | sudo -S do something
sudo do something else
exit
EOF
Set SSH up for Public Key Authentication, with no pasphrase on the Key. Loads of guides on the net. You won't need a password to login then. You can then limit connections for a key based on client hostname. Provides reasonable security and is great for automated logins.
echo <password> | su -c <command> <user>
This is working.
a better sshpass alternative is: passh
https://github.com/clarkwang/passh
Login to a remote server
$ passh -p password ssh user#host
Run a command on remote server
$ passh -p password ssh user#host date
other methods to pass the password
-p The password (Default: `password')
-p env: Read password from env var
-p file: Read password from file
here I explained why it is better than sshpass, and other solutions.
You can also pass various parameters as follows:
echo password | echo y | sudo -S pacman -Syu
(Although that's a bad idea, it's just an example)
I had the same problem. dialog script to create directory on remote pc.
dialog with ssh is easy. I use sshpass (previously installed).
dialog --inputbox "Enter IP" 8 78 2> /tmp/ip
IP=$(cat /tmp/ip)
dialog --inputbox "Please enter username" 8 78 2> /tmp/user
US=$(cat /tmp/user)
dialog --passwordbox "enter password for \"$US\" 8 78 2> /tmp/pass
PASSWORD = $(cat /tmp/pass)
sshpass -p "$PASSWORD" ssh $US#$IP mkdir -p /home/$US/TARGET-FOLDER
rm /tmp/ip
rm /tmp/user
rm /tmp/pass
greetings from germany
titus
Building on #Jahid's answer, this worked for me on macOS 10.13:
ssh <remote_username>#<remote_server> sudo -S <<< <remote_password> cat /etc/sudoers
I once had a use case where I needed to run Sudo and ssh in the same command without stdin specifying all the variables needed.
This is the command I used
echo sudopassword | sudo -S -u username sshpass -p extsshpassword ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no username#ipaddress " CMD on external machine"
Breaking that command into pieces!
This will allow you to run commands through your machine using Superuser:
echo password | sudo -S -u username
This will allow you to pass ssh password and execute commands on external machines:
sshpass -p sshpassword ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no username#ipaddress " CMD on external machine"
make sure you install the sudo and openssh packages on your machine.
One way would be to use read -s option .. this way the password characters are not echoed back to the screen. I wrote a small script for some use cases and you can see it in my blog:
http://www.datauniv.com/blogs/2013/02/21/a-quick-little-expect-script/
USE:
echo password | sudo command
Example:
echo password | sudo apt-get update; whoami
Hope It Helps..
You can provide password as parameter to expect script.
su -c "Command" < "Password"
Hope it is helpful.

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