Free Physical FIDO2 Multi Factor Authentication on AWS

In July of 2022, Amazon started to offer some customers the option of a free, physical Multi-Factor Authentication token to help secure AWS Accounts. And (at the time of writing) this is a FIDO2 Multi Factor Authentication (MFA) device.

This is a fantastic step forward.

MFA support for AWS IAM was introduced in 2009. Its expanded capability over time included Gemalto key fob devices (off-line, pre-seeded) , SMS text message (with caveats and warnings on using SMS for MFA), and FIDO 2 based devices.

The of-fline key fobs suffered from a few small flaws:

  1. The battery would go flat after some time.
  2. There was no time synchronisation, and time drift would happen to the point of not being able to be corrected if not used for extended periods of time (weeks, months, years).

The SMS approach was fraught with danger due to unauthorised mobile phone subscription take over – whereby someone walks into the retail store and convinces a young assistant that they’ve lost their phone and gets them to vend a replacement SIM card with your number, amongst other approaches.

In 2015, when there was just one AWS training course that wasn’t pre-sales free, Architecting on AWS, I was offering advanced security and operations training on AWS under my training brand, Nephology. Luckily the state of education (and certification) has expanded greatly from AWS (and others), and I no longer need to fill this gap — and my day job has become so busy I don’t get the time (despite missing out on the additional income).

At that time, FIDO2 was not supported by the AWS API and Console.

And thus, every student of Nephology for our AWS Security course from 2015 until I finished delivering my education around 2018, received from me a Gemalto MFA to help secure their master (root) credentials of their primary AWS account. My training also included actually helping enabling the MFA, and the full lifecycle of disabling and re-establishing MFA, as well as what to do when the MFA breaks, is lost, goes flat, or looses time sync.

It was a key enabler, in real terms, to help customers secure their environments better. And clearly, I was 7 years ahead of my time, with AWS now, in limited terms, making a similar offer to some of its customers.

Its amazing today to see the capability usefulness of FIDO2 devices for MFA, and I’ve long since deprecated the physical key fobs in favour of this. So long as the MFA device can be plugged in (USB3, USBC) or connected to (NFC, etc) then they’ll continue to be effective.

The flexibility of being able to use the same FIDO2 MFA device with multiple other services, outside of AWS, means it helps the general security for the individual. No one wants 20 physical MFAs; this really is the one (key) ring to rule them.