Ssh – Safely adding SSH users to pfSense

pfsensessh

I would like to add a user for myself to login via SSH to a pfSense box. I don't want to just blindly go through the adduser command and inadvertently break something / open a vulnerability somewhere though. Looking at the config page in the WebUI:

pfSense Secure Shell Config Options

I can't find where to add users or to specify their keys. What is the right way to add users that can use SSH? Can I also safely use the AllowUsers directive to keep tighter control of those allowed to login via SSH?

Bonus: I would also like to disable root from being able to login via SSH. I can see the option PermitRootLogin in the /etc/ssh/sshd_config file, though I don't necessarily want to modify it directly as I could potentially lose those changes with updates/patches or changes through the WebUI. Thoughts?

Best Answer

Are you using an older version of pfsense? In 2.0+, users are maintained under System->User Manager ( 192.168.x.1/system_usermanager.php ). When you add a new user you can also paste in an authorized key for SSH. There's also a SSHDCond package that "acts as an access list frontend for ssh connections", although I have not tried it myself (and it's listed as Beta).

Related Solutions

Ssh – How to automate SSH login with password

Don't use a password. Generate a passphrase-less SSH key and push it to your VM.

If you already have an SSH key, you can skip this step… Just hit Enter for the key and both passphrases:

$ ssh-keygen -t rsa -b 2048
Generating public/private rsa key pair.
Enter file in which to save the key (/home/username/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/username/.ssh/id_rsa.
Your public key has been saved in /home/username/.ssh/id_rsa.pub.

Copy your keys to the target server:

$ ssh-copy-id id@server
id@server's password:

Now try logging into the machine, with ssh 'id@server', and check-in:

.ssh/authorized_keys

Note: If you don't have .ssh dir and authorized_keys file, you need to create it first

to make sure we haven’t added extra keys that you weren’t expecting.

Finally, check to log in…

$ ssh id@server

id@server:~$

You may also want to look into using ssh-agent if you want to try keeping your keys protected with a passphrase.

SSH – Bad Owner or Permissions on ~/.ssh/config

I needed to have rw for user only permissions on config. This fixed it.

chmod 600 ~/.ssh/config

As others have noted below, it could be the file owner. (upvote them!)

chown $USER ~/.ssh/config

If your whole folder has invalid permissions here's a table of possible permissions:

Path	Permission
.ssh directory (code)	0700 (drwx------)
private keys (ex: `id_rsa`) (code)	0600 (-rw-------)
`config`	0600 (-rw-------)
public keys (*.pub ex: `id_rsa.pub`)	0644 (-rw-r--r--)
`authorized_keys` (code)	0644 (-rw-r--r--)
`known_hosts`	0644 (-rw-r--r--)

Sources:

openssh check-perm.c
openssh readconf.c
openssh ssh_user_config fix_authorized_keys_perms

Best Answer

Related Solutions

Ssh – How to automate SSH login with password

SSH – Bad Owner or Permissions on ~/.ssh/config

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