[X2Go-User] MFA support in X2go?

[Stefan Baur]

Am 25.05.23 um 22:54 schrieb Grigory Shamov:
> HI All,
> 
> Is there any X2go client around that would support connecting to SSH with a multi-factor auth like Duo or Yubikey enabled?

The stock X2GoClient already has built-in support for several MFA tools.

   "Verification code:",            // GA 
(http://github.com/google/google-authenticator)
   "One-time password (OATH) for",  // OATH 
(http://www.nongnu.org/oath-toolkit/pam_oath.html)
   "passcode:",                     // MOTP    (http://motp.sourceforge.net)
   "Enter PASSCODE:",               // SecurID
   "YubiKey for"                    // YubiKey 
(https://en.wikipedia.org/wiki/YubiKey)

I have successfully used the first two myself, and we have customers 
using this as well.
The neat thing about the first two is that they are free and don't 
require a hardware token - an free app on a Smartphone is enough.
Also note that even though the first one is named after Google, it does 
not require a Google account, nor does it, to my knowledge, "phone home" 
to Google. Also, you can use any generic TOTP generator on the 
Smartphone side for both, you do not have to use the Google 
Authenticator app on the smartphone side just because you're using the 
Google Authenticator plugin on the server side.
In fact, due to known security issues with it, I would recommend against 
using the Google Authenticator App on the smartphone side.
However, the server-side plugin is really neat, IMO, and I would prefer 
it over pam_oath. It has some nice features like providing you with a 
bunch of back-up, emergency codes that you can print out and store 
somewhere safe.

The one thing to remember is that you do not configure this in X2Go, but 
in SSH/PAM, as this is what X2Go uses to connect.

If you can log in via SSH using your MFA key/token, you will also be 
able to use it for X2Go. There will be an additional Pop-Up after you've 
entered username and password where you need to enter/paste the one-time 
password.

If X2GoClient doesn't show the popup, it is because the prompt (again, 
you can test/verify this via commandline SSH) doesn't match any of the 
known prompts listed above.

Kind Regards,
Stefan Baur

-- 
BAUR-ITCS UG (haftungsbeschränkt)
Geschäftsführer: Stefan Baur
Eichenäckerweg 10, 89081 Ulm | Registergericht Ulm, HRB 724364
Fon/Fax 0731 40 34 66-36/-35 | USt-IdNr.: DE268653243