Description

If you are familiar with using the ssh-agent in combination with the ssh command, you'll learn to love this script.

Basically, it helps you publish your public ID on remote system(s) such that you'll be able to easily log into them. It does this by logging into the system(s) you specify on the command line, and modifying the ${HOME}/.ssh/authorized_keys file for one or more user accounts.

[root@dev24 ~]# ssh-keygen -t rsa

Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): [PRESS ENTER] 
/root/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase): UseYourOwn 
Enter same passphrase again: UseYourOwn
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:C9ZhhwOH5y5eVXxZdQ1/WgSD7XnkTGD0nJ7XyS9RvBo root@localhost.rwh.shop
The key's randomart image is:
+---[RSA 2048]----+
|      ...  . +B*B|
|      .o..  +.+B*|
|       o= .. o BO|
|       o.+.   =+X|
|      o.S.   EoBo|
|     ...o.    o.o|
|     . o.    .. .|
|      .        . |
|                 |
+----[SHA256]-----+

[root@dev24 ~]# ls -l ~/.ssh/id_rsa*
-rw------- 1 root root 1766 May 22 12:58 /root/.ssh/id_rsa
-rw-r--r-- 1 root root  405 May 22 12:58 /root/.ssh/id_rsa.pub
[root@dev24 ~]# 

The following invocation demonstrates how one would authorize themselves for future ssh access on systems: 10.222.222.192, fortuna, and www.hfxc.com. Authorization will be granted for user accounts root and nst, and you will be prompted for credentials for each system:

[root@dev24 ~]# ssh-auth-keys -v -s 10.222.222.192:www.hfxc.com:fortuna -u root:nst -i /root/.ssh/id_rsa.pub

--------------------------------------------------------------------------
Updating host: 10.222.222.192
Updating users: root nst
Warning: Permanently added '10.222.222.192' (RSA) to the list of known hosts.
root@10.222.222.192's password: PASSWORD1
Using Public Key File: "/root/.ssh/id_rsa.pub"
Updated: "/root/.ssh/authorized_keys" for root on 10.222.222.192
Using Public Key File: "/root/.ssh/id_rsa.pub"
Updated: "/home/nst/.ssh/authorized_keys" for nst on 10.222.222.192
--------------------------------------------------------------------------

--------------------------------------------------------------------------
Updating host: www.hfxc.com
Updating users: root nst
Warning: Permanently added 'www.hfxc.com' (RSA) to the list of known hosts.
root@www.hfxc.com's password: PASSWORD2
Using Public Key File: "/root/.ssh/id_rsa.pub"
Updated: "/root/.ssh/authorized_keys" for root on www.hfxc.com
Using Public Key File: "/root/.ssh/id_rsa.pub"
Updated: "/home/nst/.ssh/authorized_keys" for nst on www.hfxc.com
--------------------------------------------------------------------------

--------------------------------------------------------------------------
Updating host: fortuna
Updating users: root nst
Warning: Permanently added 'www.hfxc.com' (RSA) to the list of known hosts.
root@fortuna's password: PASSWORD3
Using Public Key File: "/root/.ssh/id_rsa.pub"
Updated: "/root/.ssh/authorized_keys" for root on fortuna
Using Public Key File: "/root/.ssh/id_rsa.pub"
Updated: "/home/nst/.ssh/authorized_keys" for nst on fortuna
--------------------------------------------------------------------------

[root@dev24 ~]# 

Once the keys have been distributed, we can make use of ssh-agent and ssh-add to allow us to easily access the new systems:

[root@dev24 ~]# ssh-agent | tee ssh-agent.sh
SH_AUTH_SOCK=/tmp/ssh-eqGKWa3414/agent.3414; export SSH_AUTH_SOCK;
SSH_AGENT_PID=3416; export SSH_AGENT_PID;
echo Agent pid 3416;
[root@dev24 ~]# . ssh-agent.sh
Agent pid 3416
[root@dev24 ~]# rm -f ssh-agent.sh
[root@dev24 ~]# ssh-add
Enter passphrase for /root/.ssh/id_rsa: UseYourOwn
Identity added: /root/.ssh/id_rsa (/root/.ssh/id_rsa)
[root@dev24 ~]# ssh root@10.222.222.192
Last login: Fri May 22 08:34:40 2016 from 10.222.222.189

===========================================
= Linux Network Security Toolkit (NST 24) =
===========================================


[root@10.22.22.192 ~]# exit
logout
Connection to 10.222.222.192 closed.
[root@dev24 ~]# ssh root@fortuna
Last login: Mon May 21 16:10:15 2016 from 10.222.222.189

===========================================
= Linux Network Security Toolkit (NST 22) =
===========================================


[root@fortuna ~]# exit
logout
Connection to fortuna closed.
[root@dev24 ~]# ssh vpn@fortuna


===========================================
= Linux Network Security Toolkit (NST 24) =
===========================================


[vpn@fortuna ~]$ exit
logout
Connection to fortuna closed.
[root@dev24 ~]# 

Options

The following command line options are available:

Files

Environment

See Also

ssh(1), ssh-add(1), ssh-agent(1), ssh-keygen(1), OpenSSH, Network Security Toolkit