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One-Time Password (OTP) Authentication#

Overview#

This document will explain how to use Gluu's One-Time Password (OTP) interception script to configure the Gluu Server for a two-step authentication process with username and password as the first step, and OTP as the second step.

In order to use this authentication mechanism users will need to install a mobile app that supports HOTP/TOTP, like Google Authenticator.

Prerequisites#

Note

Gluu's OTP interception script uses the two-factor event/counter-based HOTP algorithm RFC4226 and the time-based TOTP algorithm RFC6238.

Sequence Diagram#

Below is the sequence diagram for TOTP/HOTP and its flow explained:

sequence diagram

TOTP/HOTP enrollment/authentication workflow#

Person->Browser: Open RP URL

Browser->RP: Protected resource

RP->Gluu Server: Start AuthZ & AuthN

OTP Script->OTP Script: Verify user/password

alt: User enrollment
    OTP Script->OTP Script: Check if person not issued OTP key already
    OTP Script->Browser: Render otpauth QR code with OTP key 
    Person->OTP comp. auth.: Scan QR code
    OTP comp. auth.->Person: New one time passowrd
    Person->Browser: Enter one time password
    Browser->OTP Script:
    OTP Script->OTP Script: Validate one time passowrd
    OTP Script->OTP Script: Strore OTP key in user entry
    OTP Script->Gluu Server: User pass enrollment
else User authentication
    OTP Script->OTP Script: Check if person issued OTP key already
    OTP comp. auth.->Person: New one time passowrd
    Person->Browser: Enter one time password
    Browser->OTP Script:
    OTP Script->OTP Script: Validate one time passowrd
    OTP Script->Gluu Server: User pass enrollment
end

Gluu Server->Browser: Return code
Browser->RP: Return code

RP->Gluu Server: Request tokens
RP->Gluu Server: Request user_info

Properties#

The module has a few properties:

1) otp_type - It's mandatory property. It's specify OTP mode: HOTP/ TOTP. Allowed values: hotp/totp Example: hotp

2) issuer - It's mandatory property. It's company name. Example: Gluu Inc

3) otp_conf_file - It's mandatory property. It's specify path to OTP configuration JSON file. Example: /etc/certs/otp_configuration.json

4) label - It's label inside QR code. It's optional property. Example: Gluu OTP

5) qr_options - Specify width and height of QR image. It's optional property. Example: qr_options: { width: 400, height: 400 }

6) registration_uri - It's URL to page where user can register new account. It's optional property. Example: https://hostname/identity/register

Configure OTP with Gluu Server#

This list of steps needed to enable OTP person authentication module.

  1. Confire new custom module in oxTrust:
    • Log into oxTrust with administrative permissions.
    • Open Configuration > Manage Custom Scripts.
    • Select `Person Authentication tab.
    • Enter name = otp
    • Enter level = 0-100 (priority of this method).
    • Select usage type Interactive.
    • Select the Location Type, if the Location type is LDAP, script would be automatically populated in the script box below.
    • If Location type is selected as text, follow the below
      • Copy/paste script from TotpExternalAuthenticator.py.
    • Activate it via Enabled checkbox.
    • Click Update button at the bottom of this page.

customscripts select-otp update

  1. Configure oxAuth to use OTP authentication by default:
    • Log into oxTrust with administrative permissions.
    • Navigate to Configuration > Manage Authentication.
    • Select Default Authentication Method tab. Select "otp" authentication mode.
    • Click Update button at the bottom of this page.

defaulttab

  1. Try to log in using OTP authentication method:
    • Wait 30 seconds and try to log in again. During this time oxAuth reload list of available person authentication modules.
    • Once the scanning of QR is done on your mobile, click on Finish to get the OTP page to enter otp from your mobile.
    • Open second browser or second browsing session and try to log in again. It's better to try to do that from another browser session because we can return back to previous authentication method if something will go wrong.

Note

Even if you have OTP generated on the mobile authenticator app, you might have to scan the qr code again, if you are logging in from different computer or at a different time or for a different session. Since the QR code would expire after some time.

login scanqr

There are log messages in this custom authentication script. In order to debug this module we can use below command.

tail -f /opt/gluu/jetty/identity/logs/oxtrust.log | grep "OTP"

and

tail -f /opt/gluu/jetty/identity/logs/oxtrust_script.log | grep "OTP"

Don't have a QR code to scan:#

If you have changed your mobile or you have reinstalled Google Authenticator app, and if the app is looking for QR code to scan, and you don't see a QR code. Open Gluu LDAP server using a LDAP browser and navigate to appliances and search for an attribute oxExternalUid. Remove the values of this attribute.

Note

Logs are populated only if logs are enabled. For more info on logs refer to the Log management section of the docs.