YubiKey Multi-Factor Authentication on Ubuntu Server 20.04 - Part 1
TLDR: Setting up YubiKey OTP as a second-factor (password + OTP) for authentication on Ubuntu 20.04 using PAM. This is the first post on a series where I want to explore various authentication mechanisms for Linux, and their integration with YubiKeys. I found that the resources already available on the internet were lacking, incomplete or outdated, so I decided to write my own. I have multiple systems on my network, and managing credentials is a huge pain. The end goal will be to explore ways to have a central authentication server which supports YubiKeys. I strongly suggest testing the setup first using disposable servers first. I did not follow this suggestion and ended up locking myself out of one of my servers! It is also a good idea to have multiple terminals open, in case you make a change and it does not work, you can use the second one to revert back. Requirements Ser ver running Ubuntu Server 20.04.2. I am using a fully-updated server as of the time of writing Yubico