I want to change RSA Keys to open ssh connections without any problems. It works fine, if I use this tutorial but I want to have it done in a bash script. Unfortunately I am asked to enter a passphrase (I want to enter nothing). How can I achieve to automatically press Enter three times in a row, when the script reaches this point?
This thread did not help, because I am not allowed to install new programs on my work PC and the echo | command trick seems only to work for one Enter. Also I need to enter "n" and Enter, if the procedure was already made, to not overwrite any files. How do i achieve that?
If you just need to press Enter a bunch of times this will do it:
yes "" | command
For anything more complicated than that you might want to use expect as suggested in the other thread, which you can install in your homedir without root priviliges.
PS: Please avoid re-posting questions in the future. If you don't like an answer for some reason, just comment on it.
If you want to just create ssh keys in a bash script without requiring any user input, you can specify arguments to ssh-keygen:
# rsa type (default), no passphrase, write to file id_rsa and id_rsa.pub
captain:~> ssh-keygen -t rsa -N "" -f id_rsa
Generating public/private rsa key pair.
Your identification has been saved in id_rsa.
Your public key has been saved in id_rsa.pub.
The key fingerprint is:
fe:4a:82:08:0e:ab:b7:02:62:11:4d:3e:79:a4:d3:98 mrb#captain.local
Related
I'm getting the standard
WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
error message. However, the system (Appworx) that executes the command (sftp I think, not that it matters) is automated and I can't easily accept the new key, even after checking with the third party vendor that it is a valid change. I can add a new shell script that I can execute from the same system (and user), but there doesn't seem to be a command or command-line argument that will tell ssh to accept the key. I can't find anything in the man page or on Google. Surely this is possible?
The answers here are terrible advice. You should never turn off StrictHostKeyChecking in any real-world system (e.g. it's probably okay if you're just playing on your own local home network – but for anything else don't do it).
Instead use:
ssh-keygen -R hostname
That will force the known_hosts file to be updated to remove the old key for just the one server that has updated its key.
Then when you use:
ssh user#hostname
It will ask you to confirm the fingerprint – as it would for any other "new" (i.e. previously unseen) server.
While common wisdom is not to disable host key checking, there is a built-in option in SSH itself to do this. It is relatively unknown, since it's new (added in Openssh 6.5).
This is done with -o StrictHostKeyChecking=accept-new.
WARNING: use this only if you absolutely trust the IP\hostname you are going to SSH to:
ssh -o StrictHostKeyChecking=accept-new mynewserver.example.com
Note, StrictHostKeyChecking=no will add the public key to ~/.ssh/known_hosts even if the key was changed.
accept-new is only for new hosts. From the man page:
If this flag is set to “accept-new” then ssh will automatically add
new host keys to the user known hosts files, but will not permit
connections to hosts with changed host keys. If this flag
is set to “no” or “off”, ssh will automatically add new host keys
to the user known hosts files and allow connections to hosts with
changed hostkeys to proceed, subject to some restrictions.
If this flag is set to ask (the default), new host keys will be
added to the user known host files only after the user has confirmed
that is what they really want to do, and ssh will refuse to
connect to hosts whose host key has changed.
The host keys of known hosts will be verified automatically in all cases.
Why -o StrictHostKeyChecking=no is evil?
When you do not check the host key you might land with an SSH session on a different computer (yes, this is possible with IP Hijacking). A hostile server, which you don't own can be then used to steal a password and all sort of data.
Accepting a new unknown key is also pretty dangerous.
One should only do it if there is an absolute trust in the network or that the server was not compromised.
Personally, I use this flag only when I boot machines in a cloud environment with cloud-init immediately after the machine started.
Here's how to tell your client to trust the key. A better approach is to give it the key in advance, which I've described in the second paragraph. This is for an OpenSSH client on Unix, so I hope it's relevant to your situation.
You can set the StrictHostKeyChecking parameter. It has options yes, no, and ask. The default is ask. To set it system wide, edit /etc/ssh/ssh_config; to set it just for you, edit ~/.ssh/config; and to set it for a single command, give the option on the command line, e.g.
ssh -o "StrictHostKeyChecking no" hostname
An alternative approach if you have access to the host keys for the remote system is to add them to your known_hosts file in advance, so that SSH knows about them and won't ask the question. If this is possible, it's better from a security point of view. After all, the warning might be right and you really might be subject to a man-in-the-middle attack.
For instance, here's a script that will retrieve the key and add it to your known_hosts file:
ssh -o 'StrictHostKeyChecking no' hostname cat /etc/ssh/ssh_host_dsa_key.pub >>~/.ssh/known_hosts
Since you are trying to automate this by running a bash script on the host that is doing the ssh-ing, and assuming that:
You don't want to ignore host keys because that's an additional security risk.
Host keys on the host you're ssh-ing to rarely change, and if they do there's a good, well-known reason such as "the target host got rebuilt"
You want to run this script once to add the new key to known_hosts, then leave known_hosts alone.
Try this in your bash script:
# Remove old key
ssh-keygen -R $target_host
# Add the new key
ssh-keyscan $target_host >> ~/.ssh/known_hosts
You just have to update the current fingerprint that's being sent from server. Just Type in the following and you'll be good to go :)
ssh-keygen -f "/home/your_user_name/.ssh/known_hosts" -R "server_ip"
Just adding the most 'modern' approach.
Like all other answers - this means you are BLINDLY accepting a key from a host. Use CAUTION!
HOST=hostname ssh-keygen -R $HOST && ssh-keyscan -Ht ed25519 $HOST >> "$HOME/.ssh/known_hosts"
First remove any entry using -R, and then generate a hashed (-H) known_hosts entry which we append to the end of the file.
As with this answer prefer ed25519.
Get a list of SSH host IPs (or DNS name) output to a file > ssh_hosts
Run a one-liner to populate the ~/.ssh/known_hosts on the control node (often do this to prepare target nodes for Ansible run)
NOTE: Assume we prefer ed25519 type of host key
# add the target hosts key fingerprints
while read -r line; do ssh-keyscan -t ed25519 $line >> ~/.ssh/known_hosts; done<ssh_hosts
# add the SSH Key('s) public bit to target hosts `authorized_keys` file
while read -r line; do ssh-copy-id -i /path/to/key -f user#$line; done<ssh_hosts
ssh -o UserKnownHostsFile=/dev/null user#host
Add following file
~/.ssh/config
and this in the file as content
StrictHostKeyChecking no
This setting will make sure that ssh will never ask for fingerprint check again.
This should be added very carefully as this would be really dangerous and allow to access all fingerprints.
I'm getting the standard
WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
error message. However, the system (Appworx) that executes the command (sftp I think, not that it matters) is automated and I can't easily accept the new key, even after checking with the third party vendor that it is a valid change. I can add a new shell script that I can execute from the same system (and user), but there doesn't seem to be a command or command-line argument that will tell ssh to accept the key. I can't find anything in the man page or on Google. Surely this is possible?
The answers here are terrible advice. You should never turn off StrictHostKeyChecking in any real-world system (e.g. it's probably okay if you're just playing on your own local home network – but for anything else don't do it).
Instead use:
ssh-keygen -R hostname
That will force the known_hosts file to be updated to remove the old key for just the one server that has updated its key.
Then when you use:
ssh user#hostname
It will ask you to confirm the fingerprint – as it would for any other "new" (i.e. previously unseen) server.
While common wisdom is not to disable host key checking, there is a built-in option in SSH itself to do this. It is relatively unknown, since it's new (added in Openssh 6.5).
This is done with -o StrictHostKeyChecking=accept-new.
WARNING: use this only if you absolutely trust the IP\hostname you are going to SSH to:
ssh -o StrictHostKeyChecking=accept-new mynewserver.example.com
Note, StrictHostKeyChecking=no will add the public key to ~/.ssh/known_hosts even if the key was changed.
accept-new is only for new hosts. From the man page:
If this flag is set to “accept-new” then ssh will automatically add
new host keys to the user known hosts files, but will not permit
connections to hosts with changed host keys. If this flag
is set to “no” or “off”, ssh will automatically add new host keys
to the user known hosts files and allow connections to hosts with
changed hostkeys to proceed, subject to some restrictions.
If this flag is set to ask (the default), new host keys will be
added to the user known host files only after the user has confirmed
that is what they really want to do, and ssh will refuse to
connect to hosts whose host key has changed.
The host keys of known hosts will be verified automatically in all cases.
Why -o StrictHostKeyChecking=no is evil?
When you do not check the host key you might land with an SSH session on a different computer (yes, this is possible with IP Hijacking). A hostile server, which you don't own can be then used to steal a password and all sort of data.
Accepting a new unknown key is also pretty dangerous.
One should only do it if there is an absolute trust in the network or that the server was not compromised.
Personally, I use this flag only when I boot machines in a cloud environment with cloud-init immediately after the machine started.
Here's how to tell your client to trust the key. A better approach is to give it the key in advance, which I've described in the second paragraph. This is for an OpenSSH client on Unix, so I hope it's relevant to your situation.
You can set the StrictHostKeyChecking parameter. It has options yes, no, and ask. The default is ask. To set it system wide, edit /etc/ssh/ssh_config; to set it just for you, edit ~/.ssh/config; and to set it for a single command, give the option on the command line, e.g.
ssh -o "StrictHostKeyChecking no" hostname
An alternative approach if you have access to the host keys for the remote system is to add them to your known_hosts file in advance, so that SSH knows about them and won't ask the question. If this is possible, it's better from a security point of view. After all, the warning might be right and you really might be subject to a man-in-the-middle attack.
For instance, here's a script that will retrieve the key and add it to your known_hosts file:
ssh -o 'StrictHostKeyChecking no' hostname cat /etc/ssh/ssh_host_dsa_key.pub >>~/.ssh/known_hosts
Since you are trying to automate this by running a bash script on the host that is doing the ssh-ing, and assuming that:
You don't want to ignore host keys because that's an additional security risk.
Host keys on the host you're ssh-ing to rarely change, and if they do there's a good, well-known reason such as "the target host got rebuilt"
You want to run this script once to add the new key to known_hosts, then leave known_hosts alone.
Try this in your bash script:
# Remove old key
ssh-keygen -R $target_host
# Add the new key
ssh-keyscan $target_host >> ~/.ssh/known_hosts
You just have to update the current fingerprint that's being sent from server. Just Type in the following and you'll be good to go :)
ssh-keygen -f "/home/your_user_name/.ssh/known_hosts" -R "server_ip"
Just adding the most 'modern' approach.
Like all other answers - this means you are BLINDLY accepting a key from a host. Use CAUTION!
HOST=hostname ssh-keygen -R $HOST && ssh-keyscan -Ht ed25519 $HOST >> "$HOME/.ssh/known_hosts"
First remove any entry using -R, and then generate a hashed (-H) known_hosts entry which we append to the end of the file.
As with this answer prefer ed25519.
Get a list of SSH host IPs (or DNS name) output to a file > ssh_hosts
Run a one-liner to populate the ~/.ssh/known_hosts on the control node (often do this to prepare target nodes for Ansible run)
NOTE: Assume we prefer ed25519 type of host key
# add the target hosts key fingerprints
while read -r line; do ssh-keyscan -t ed25519 $line >> ~/.ssh/known_hosts; done<ssh_hosts
# add the SSH Key('s) public bit to target hosts `authorized_keys` file
while read -r line; do ssh-copy-id -i /path/to/key -f user#$line; done<ssh_hosts
ssh -o UserKnownHostsFile=/dev/null user#host
Add following file
~/.ssh/config
and this in the file as content
StrictHostKeyChecking no
This setting will make sure that ssh will never ask for fingerprint check again.
This should be added very carefully as this would be really dangerous and allow to access all fingerprints.
I use this command on git bash
`$ ssh-keygen -t rsa -C "eu.json#gmail.com"`
After that, these line of text show.
`'Generating public/private rsa key pair.
Enter file in which to save the key (/c/Users/jayson/.ssh/id_rsa):'.`
There is no other line of text shown and stuck there, I wait for long time and still nothing happen not like the video that i follow, I need to use it on laravel homestead.
You are supposed to click ENTER (twice if you don't want a passphrase associated to the private key).
That will validate the file to be saved.
/c/Users/jayson/.ssh/id_rsa (private key)
/c/Users/jayson/.ssh/id_rsa.pub (public key)
I've followed the following guide to setup SSH keys on Mac OS 10.7.4.
https://help.github.com/articles/generating-ssh-keys
But for some reason it continually prompts me for my passphrase. It doesn't prompt me if I don't specify a passphrase, but that isn't desired. Is there a way to cache my passphrase so that I won't be prompted for every pull/push?
You have to add your key file in the ssh-add
ssh-add ~/.ssh/you_key_rsa
After that, it's not will ask any more.
You might need to edit the .git/config file in your git repo and change the url value to use something like user#host:path-to-git-repo.git
The SSH password is used to authenticate users connecting to GIT repositories.
If you're working localy, git shouldn't ask for passwords, obly when doing remote operation, such as clone, push, pull,etc.
If the password annoys you, you can just input a blank password when creating the SSH key, password is not mandatory, however I advise you to use password for extra protection.
I am using Windows 10, and I have found two ways to eliminate the passphrase prompting.
Make sure the ssh agent is started and you have added your key
$ eval "$(ssh-agent -s)"
$ ssh-add ~/.ssh/id_rsa
The second command will prompt you for your passphrase, and then you will not be prompted for any other git commands run in this session.
You will need to run these commands again for every new bash session
Remove the passphrase from you key file:
$ ssh-keygen -p -f ~/.ssh/id_rsa
When prompted, just strike enter key for the new passphrase.
Option 2 will permanently remove the passphrase for all git commands. Of course it also makes you key file "unsecured"
Note: If you are using git desktop GUI ( Version 1.04+) Option 2 is required for the GUI to work.
I am attempting to connect to an Amazon EC2 Server via Mac Terminal. I have a PPK file that does not have a password attached to it, but when I try to connect I get a popup box that says "Enter the password for the SSH Private Key."
So we tried creating a PPK that has a password - but it does not accept the password, it still rejects the connection.
I have a Windows user who is able to connect using the same PPK on Putty.
Has anyone experienced this issue?
The mac is looking for a .pem key. The ppk is generated specifically for putty. If you don't have the original ppk key.
Download puttygen.exe from http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html Then go to conversions -> export OpenSSH key. Save the output as a .pem file and try using that with the mac.
If this doesn't work can you post the command you're running from mac. Its possible you've got some extra parameter or something.
Maybe your problem is with permissions for your key. I know in linux its required to change the permissions.
Taken from the website http://om4.com.au/ssh-rsa-key-pairs-passphrases-leopard/
Clear the contents of your ~/.ssh directory and set the directory permissions to 700 (directories need to be "executable")
$ rm ~/.ssh/*
$ chmod 700 ~/.ssh
Generate your rsa key pair (there are variations for this, but this is the version I used):
$ ssh-keygen -t rsa
Set the permissions for all files in ~/.ssh to 600
$ chmod 600 ~/.ssh
Copy your id_rsa.pub key to your server’s .ssh/authorized_keys file
Add your passphrase to your keychain using this command:
$ ssh-add -K
(you will see Enter passphrase for [your system]/.ssh/id_rsa: )
The error Enter your password for the SSH key x can result from using a key of the wrong format (such as a ppk key) in ssh or sftp. This is because it is interpreted as an encrypted ssh key and so prompts for the passphrase, when actually there is no passphrase.
In OS X I was able to simulate this error by simply typing the following into the command line:
sftp -o IdentityFile=randomtextfile mysftpserver.com
The solution is to convert the file using puttygen as suggested by bwight.
In addition to the other answers, the issue might come from the fact you haven't specified which user you want to connect as.
For example ssh -i francky.pem 208.52.170.43 will ask you for your password on Mac, whereas ssh -i francky.pem root#208.52.170.43 shouldn't. Note that on Linux you don't specify the user.
I was running into the exact same problem in MAC, I found a quite simple way of getting rid of it.
Instead of using ssh -i IP address, use the following>
ssh user#IP
Hope you already found the answer after this long time :)
In my case, the problem was the file's break type. Try this:
1.- Open the .pem file with TextWrangler
2.- At Bottom of app, verify if the Break Type is "Windows(CRLF)".
This issue had me pulling my hair out for 20 min or so. Realized that I was able to connect successfully from another terminal window. In my case I just had to close out the current terminal window and use another or new window. Very strange, but may help you out.