MFA Tutorial – Yubikey Usage for both Console and SSH

For a while now I’ve been curious about the application of multi-factor authentication for Linux console and SSH access. It’s a particularly challenging use-case, especially if you operate in an air-gapped configuration, and yet need to meet industry standards such as PCI’s Control 8.5.1, or NIST 800-53’s Control IA-2(1). Multi-factor is essentially a requirement to …