[Thorrez]

>It depends on the dongle. YubiKeys and similar devices require the user to physically touch/tap it to enable U2F auth, and it automatically powers down after a timeout to prevent remote desktop attacks.

How often is the tap needed? Is it needed on every action or 1/day or 1/month? It would stay valid via browser cookies valid for that period. If it's 1/day the employee might have tapped it in the morning, then went to lunch, then the attackers hit with the remote desktop attack.

[pseudoramble]

Every time you login with a Yubikey you must tap it. It does not maintain its own session on the key or anything like that.

If the app maintains a session, then that depends on how long the app allows sessions/tokens to live for at that point. The Yubikey won't come into play until login is required again. So, I think you're getting at a different part of the security model at that point.

[Thorrez]

My point is that essentially all apps maintain a session and a remote desktop attack can make use of that session. So Yubikey doesn't really protect from remote desktop attacks.

[pseudoramble]

Fair enough! I didn't comprehend the context well enough. Seems right though, the Yubikey won't protect sessions. At least I don't see any reason it would.