Knowledge of the account is an obvious caveat.
Yubikey-based MFA is an added layer of protection for accounts, so any kind of attack against MFA assumes the attacker already knows which account to target.
It’s like saying “our door lock is flawed, but the attacker would need to have knowledge of the door”.
The cost and complexity is what’s noteworthy and is more relevant. Although attack cost and complexity usuallu goes down with advances in tooling and research. So it may be a good idea to plan a progressive retirement of affected keys.
Knowledge of the account is an obvious caveat. Yubikey-based MFA is an added layer of protection for accounts, so any kind of attack against MFA assumes the attacker already knows which account to target.
It’s like saying “our door lock is flawed, but the attacker would need to have knowledge of the door”.
The cost and complexity is what’s noteworthy and is more relevant. Although attack cost and complexity usuallu goes down with advances in tooling and research. So it may be a good idea to plan a progressive retirement of affected keys.