I want to write one shell script like
command1
ssh vivek#remotehost
fire command on remote host
Now I have password in pass.txt . But when I change stdin with file. It is not reading password from file.
script.sh < password.txt
It is prompting for the password in place of reading password from the file.
What I am doing wrong ?
Second problem is that shell script don't shows the command fired. Is there a way , I can show fired command from it ?
Note :
I don't have key based access on remote system. I can only use password based login for ssh.
You can use ssh-agent or expect (the programing language) to do this.
OpenSSH ssh does not reads the password from stdin but from /dev/tty. That's why you have to use Expect or some other similar tool to automate it.
plink is another client, also available for Linux/Unix that accepts the password as a parameter on the command line... though that has some ugly security implications.
Okay, just to mention yet another option: sshpass is a tool developed for exactly the task of "fooling" regular openssh client to accept password non-interactively.
Related
I'm running a script that copies files from another server.... It's prompting for a password of that server... Every time I need to enter the password manually... So s there any way to automate this?
scp root#ip:file_location destination
Note for security purposes I was not supposed to use password less login, or ssh
You can try to use sshpass which takes the password from an evironment variable named "SSHPASS" if switch -e is provided. So you can use something like:
export SSHPASS=<yourpw>
sshpass -e scp <sourcefile> user#ip:<targetpath/filename>
But of course it still uses ssh underneath, like Sergiy explained in the comment.
I have to write a shell script which ssh to another server with other username without actually asking for a password from the user?
Due to constraints I cannot use key based authentication.
let,
Source Server -- abc.efg.com
Source UserName -- tom
Source Password -- tom123
Destination Server -- xyz.efc.com
Destination UserName -- bob
destination Password -- bob123
I have to place the bash script in source server.
Please let me know if something could be done using expect tool and/or sshpass.
It is okay for me to hardcode the password for destination server in the bash script but I cannot bear an interactive session, simply when I run he script, I want to see the destination server logged in with another username.
Thanks in Advance.
You want to use key-authentication http://ornellas.apanela.com/dokuwiki/pub:ssh_key_auth
Generate your keys ssh-keygen
Copy the keys to your new box ssh-copy-id -i ~/.ssh/id_rsa.pub me#otherhost.com
ssh to other host without password ssh me#otherhost.com
You can use expect to wrap ssh, but it's pretty hectic, and fails easily when there are network errors, so test it well or use a script specifically designed for wrapping ssh passwords. Key based authentication is better.
You can prevent interactive sessions by redirecting standard input from the null device, ie.
ssh me#destination destination-command < /dev/null
About placing the script in the source server, if the script you are running is local, rather than remote, then you can pass the script on standard input, rather than the command line:
cat bashscript.sh | ssh me#destination
You can install the sshpass program, which lets you write a script like
#!/bin/bash
sshpass -p bob123 ssh UserName#xyz.efc.com
The answer is that you can't as OpenSSH actively prevent headless password-based authentication. Use key-based authentication.
You may be able to fork the OpenSSH client code and patch it, but I think that is a bit excessive.
I want to install a software library (SWIG) on a list of computers (Jenkins nodes). I'm using the following script to automate this somewhat:
NODES="10.8.255.70 10.8.255.85 10.8.255.88 10.8.255.86 10.8.255.65 10.8.255.64 10.8.255.97 10.8.255.69"
for node in $NODES; do
scp InstallSWIG.sh root#$node:/root/InstallSWIG.sh
ssh root#$node sh InstallSWIG.sh
done
This way it's automated, except for the password request that occur for both the scp and ssh commands.
Is there a way to enter the passwords programmatically?
Security is not an issue. I’m looking for solutions that don’t involve SSH keys.
Here’s an expect example that sshs in to Stripe’s Capture The Flag server and enters the password automatically.
expect <<< 'spawn ssh level01#ctf.stri.pe; expect "password:"; send "e9gx26YEb2\r";'
With SSH the right way to do it is to use keys instead.
# ssh-keygen
and then copy the *~/.ssh/id_rsa.pub* file to the remote machine (root#$node) into the remote user's .ssh/authorized_keys file.
You can perform the task using empty, a small utility from sourceforge. It's similar to expect but probably more convenient in this case. Once you have installed it, your first scp will be accomplished by following two commands:
./empty -f scp InstallSWIG.sh root#$node:/root/InstallSWIG.sh
echo YOUR_SECRET_PASSWORD | ./empty -s -c
The first one starts your command in the background, tricking it into thinking it's running in interactive mode on a terminal. The other one sends it data from stdin. Of course, putting your password anywhere on command line is risky due to shell history being preserved, users being able to see it in ps results etc. Not secure either, but a bit better thing would be to store the password in a file and redirect the second command's input from that file instead of using echo and a pipe.
After copying to the server, you can run the script in a similar manner:
./empty -f ssh root#$node sh InstallSWIG.sh
echo YOUR_SECRET_PASSWORD | ./empty -s -c
You could look into setting up passwordless ssh keys for that. Establishing Batch Mode Connections between OpenSSH and SSH2 is a starting point, you'll find lots of information on this topic on the web.
Wes' answer is the correct one but if you're keen on something dirty and slow, you can use expect to automate this.
This question already has answers here:
How to run the sftp command with a password from Bash script?
(12 answers)
Closed 7 years ago.
I am trying to write a script to back up a file over SFTP. The problem is, it requires a password, and I see no way to manually specify a password to SFTP. I've heard about requiring no password by using public keys, but that requires being able to ssh into the remote server and modify some configuration files, which I cannot do.
Currently my solution is to use cURL, but that is insecure (uses normal FTP). I also looked at the .netrc file, but that seems to be for FTP instead of SFTP. How do I manually specify a password for sftp?
Lftp allows specifying passwords for both ftp and sftp and does not require public keys at all. Your sh sync script may look like this:
#!/bin/sh
# Define folders
THEFOLDER='/mnt/my/folder'
# List files
THEFILES=`ls -p $THEFOLDER | grep -v "/"`
for file in $THEFILES
do
echo "Processing $file"
lftp -u login,password -e "put $THEFOLDER/$file;quit" theftp/sub/folder
done
cURL can support sftp, as documented by the manual:
USING PASSWORDS
FTP
To ftp files using name+passwd, include them in the URL like:
curl ftp://name:passwd#machine.domain:port/full/path/to/file
or specify them with the -u flag like
curl -u name:passwd ftp://machine.domain:port/full/path/to/file
FTPS
It is just like for FTP, but you may also want to specify and use
SSL-specific options for certificates etc.
Note that using FTPS:// as prefix is the "implicit" way as described in the
standards while the recommended "explicit" way is done by using FTP:// and
the --ftp-ssl option.
SFTP / SCP
This is similar to FTP, but you can specify a private key to use instead of
a password. Note that the private key may itself be protected by a password
that is unrelated to the login password of the remote system. If you
provide a private key file you must also provide a public key file.
You might also want to consider using python (the paramiko module), as it can quickly be called from the shell.
Install the Module
pip install paramiko
Example FTP Upload Script
import paramiko
username = 'my_username'
password = 'my_password'
transport = paramiko.Transport((server, 22))
transport.connect(username=username, password=password)
sftp = paramiko.SFTPClient.from_transport(transport)
local_filename = '/tmp/filename'
remote_filename = 'MyFiles/temp.txt'
sftp.put( local_filename, remote_filename )
Bash program to wait for sftp to ask for a password then send it along:
#!/bin/bash
expect -c "
spawn sftp username#your_host
expect \"assword\"
send \"your_password_here\r\"
interact "
Put that in a file called sftp_autologin.sh. The \r sends an to sftp to execute the command. I don't include the 'p' in password because on some systems it's uppercase, others lowercase. expect spawns the sftp command. Waits for the string 'assword' to be seen and sends a command. Then ends.
To get this to work:
Install expect, I'm using 5.44.1.15
Make sure you can sftp to your box in interactive mode and supply a password.
Make sure this bash script has executable permissions.
Then run it:
chmod +x sftp_autologin.sh
./sftp_autologin.sh
It should drop you into the sftp commandline without prompting you for a password.
Is it insecure?
It's about the most unsecure command you can run. It exposes the password to the commandline history, to anyone else who can read 'ps' output, and basically defeats the entire purpose of passwords all together.
But hey what's another log on the fraud fire, it's only about 250b dollars in victim losses per year. Lets go for 500b.
This automatically runs some commands with the sftp shell and exits automatically when done:
#!/bin/bash
expect -c "
spawn sftp myuser#myserver.com
expect \"assword\"
send \"yourpassword\r\"
expect \"sftp\"
send \"get your_directory/yourfilename.txt\r\"
expect \"sftp\"
send \"exit\r\"
interact "
In order to use public keys you do not need to modify any "configuration files". You merely need to leave a copy of your public key in a place where ssh knows to look (normally ~/.ssh/authorized_keys). You can do this with sftp. If you haven't established any authorized_keys file on the server, you can simply put your id_rsa.pub file in its place.
You can't specify a password to ssh / scp or sftp from the command line. The only way to connect without prompting for a password is to use public key authentication.
You say that you can't ssh to the server to modify configuration files but if you can sftp to the server you can probably upload your public key.
Your public key just has to go under the .ssh directory in your home directory.
When I try to use an ssh command in a shell script, the command just sits there. Do you have an example of how to use ssh in a shell script?
Depends on what you want to do, and how you use it. If you just want to execute a command remotely and safely on another machine, just use
ssh user#host command
for example
ssh user#host ls
In order to do this safely you need to either ask the user for the password during runtime, or set up keys on the remote host.
First, you need to make sure you've set up password-less (public key login). There are at least two flavors of ssh with slightly different configuration file formats. Check the ssh manpage on your system, consult you local sysadmin or head over to How do I setup Public-Key Authentication?.
To run ssh in batch mode (such as within a shell script), you need to pass a command you want to be run. The syntax is:
ssh host command
If you want to run more than one command at the same time, use quotes and semicolons:
ssh host "command1; command2"
The quotes are needed to protect the semicolons from the shell interpreter. If you left them out, only the first command would be run remotely and all the rest would be run on the local machine.
You need to put your SSH public key into the ~/.ssh/authorized_keys file on the remote host. Then you'll be able to SSH to that host password-less.
Alternatively you can use ssh-agent. I would recommend against storing the password in the script.
You can use expect command to populate the username/password info.
The easiest way is using a certificate for the user that runs the script.
A more complex one implies adding to stdin the password when the shell command asks for it. Expect, perl libraries, show to the user the prompt asking the password (if is interactive, at least), there are a lot of choices.