SecSign ID Plugin: Linux Desktop Login

2017-07-31 5 minutes to read
Tutorial Index

Two-Factor Authentication for Linux Desktop Login

The Pluggable Authentication Modules (PAM) is a software library which offers a general programming interface for authentication services. By using the PAM-API one does no longer need to define the settings for every single authentication application. Instead, individual standardized modules can be used. The modules can be assigned to individual services in the configuration file. There is no need to change the compilation of the corresponding software. PAM is available for AIX, HP-UX, Solaris, Linux, FreeBSD, NetBSD, Mac OS X and DragonFly BSD.

PAM Overview

Integration of the plugin into your setup

SecSign ID Integration

Please configure your desired integration of the SecSign ID Two Factor Authentication

Choose a system, where you want to add the secure login

Do you need your own ID Server inside your protected network or prefer if we manage and maintain it for you

The location to save the assigned SecSign IDs to a user account or the IDM alltogether

System to protect
The System you want to protect - Choose a system, where you want to add the secure login
SecSign ID Server location
Do you need your own ID Server inside your protected network or prefer if we manage and maintain it for you
User account location
The system to save the assigned SecSign IDs to a user account or the IDM alltogether
edit the settings to change the integration
2FA blind
2FA no AP
2SA no AP
2SA blind
Custom ID
IDP Custom Website
Enrollment initiated by SP
Enrollment with IDM
Show Network
Hide Network
Request Solution
The authentication was successful

Installation of the plugin

Please read the SecSign ID PAM Tutorial before using the SecSign ID PAM for Linux Desktop Authentication. Follow steps 3 to 5 to configure and install PAM correctly.


Configuration of the plugin

In this example, we use the Ubuntu flavor. To add two-factor authentication to the graphical login, open the configuration file /etc/pam.d/lightdm and activate the utilization of the SecSignID PAM:

auth required nullok

Save the file and reboot the SSH server with

sudo service ssh restart

Log out and try the SecSign ID Two-Factor Authentication.

linux login 2fa with secsignid



Compilation errors

The library libcurl needs to be installed in the standard path, otherwise make fails. If libcurl is not on the standard path the compilation needs to be executed manually.

Authentication errors

If the authentication fails the debug- and logmodus should be activated (see PAM debug- and logmodus) and the output should be written in a file. This is necessary since PAM normally needs to be silent and does not allow for output for security reasons. If no log- or debug-files are generated the paths provided in secsignid.c are incorrect or no read-and-write authorizations are available.

A log-file is produced stating all errors. It is determined if libcurl works accurate, if the SecSign ID server is available, if port 443 is available to communicate with the server, if the configuration file is available and if PAM has reading authorization.

A debug file is created which records the interface communication. It is determined wether errors in the communication persists because no SecSign ID for the specific user was found or if there are errors in a different parameter, for example the service name.


Because we just enabled the 2FA for graphical logins, it should be easy to disable if it causes a problem. Press a key combination like Ctrl + Alt + F2 to access a virtual terminal and log in there with your username and password. You can then use a command like

sudo nano /etc/pam.d/lightdm 

to open the file for editing in a terminal text editor. Save the file and you’ll be able to log in normally again.

Your own ID-Server

On premise installations of SecSign ID offer the flexibility to connect with your preferred servers, services, and devices. And you can customize the SecSign ID with your own organization’s branding.

Learn More
On Premise 2FA ID

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