Comment by fc417fc802 4 days ago
Why should I need a separate device? Doesn't a hardware security token suffice? I wouldn't even mind bringing my own but my bank doesn't accept them last I checked. (Do any of them?)
If the bank can't be bothered to either implement support for U2F or else clearly articulate why U2F isn't sufficient then they don't have a valid position. Anything else they say on the matter should be disregarded.
A hardware token would not suffice. When you login with a hardware token it will generate some sort of token or cookie for further requests. This is where malware can steal that key and use it for whatever it wants. There is a benefit it knowing there is a high chance that the such a key is protected by the operating system's sandboxing technology. Without remote attestation you don't know if the sandbox is actually active or not.
On the contrary, a hardware token will suffice to thwart both phising and MitM which covers ~everything for all practical threat and liability models. What exactly is the concern here? A widespread worm that no one is yet aware of that's dumping people's bank accounts into crypto? It might make for a decent Hollywood plot but is pulling that off actually easier than attacking the bank directly?
Keep in mind that the businesses pushing this stuff still don't support U2F by and large. When I can go down in person to enroll a hardware token I might maybe consider listening to what they have to say on the subject. Maybe. (But probably not.)
Hypothetically on a fully controlled system you could prevent attacks like the sort of “hello this is Microsoft, we’ve identified a virus on your device, please download teamviewer and login to your bank account so we can clear it for you” type spam calls.
Or, hasn’t there been malware that periodically takes screenshots of the device? Or maybe that’s a Hollywood plot, I forget actually.
Keep in mind that a truly clueless user will most likely be running in a stock configuration. So long as that doesn't permit apps to tamper with one another (as is currently the case) there should be no issue. Google could even provide a toggle to officially root the phone and so long as flipping it wiped the device the problem would remain 99.9% solved because a scammer would be unable to pull the job off in one go.
By the time you reach the point that the user is doggedly following harmful step by step instructions over the course of multiple callbacks there is nothing short of a padded cell that can protect him from himself.
Unless you mean to suggest somehow screening such calls? A local LLM? Literal wiretapping via realtime upload to the cloud? If facing such a route society would likely be better off institutionalizing anyone victimized in such a manner.
> hasn’t there been malware that periodically takes screenshots of the device?
Yeah, it's called Recall and its baked into Windows as a "feature."
It's unfortunate because it's actually incredibly useful functionality. If only they hadn't packaged and marketed it in quite the way they did. If there was ever a feature that needed to be guaranteed local only, zero third party integration, zero first party analytics, encryption tied to a TPM that was it.
How does it solve MITM? You type your hardware token in and then an attacker uses it to send money out of your account.
>What exactly is the concern here?
Stealer malware. Or even RATs where attackers get notified when you open a sensitive app and they can take over after you have authenticated.
Could you please spell out the specifics of this scenario?
MitM via an evil (ie incorrect) domain name is prevented because U2F (and now webauthn or CTAP2) are origin bound.
RATs? On stock android? How does that work? And how are the things you describe not also threats for online banking via a browser? It's certainly not how the vast majority of attacks take place in the wild. Can you provide any examples of such an attack (ie malware as opposed to phishing) that was widespread? Otherwise I assume we're writing a script for Hollywood here.
Even then, a RAT could be trivially defeated by requiring a second one-off token authentication for any transaction that would move money around. I doubt there'd be much objection to such a policy. If people really hate it let them opt out below an amount of their choosing by signing a liability waiver.
You shouldn't need a separate device, but we are quickly entering an era where a lot of banking (and other) apps will outright refuse to run or allow logins if it detects a rooted device, or play integrity fails.
In this way, the banks are asserting control over your device. It's beyond authentication, they are saying "If you have full control over your device, you cannot access our services."
I'll agree with you that they don't have a valid position, because I can just as easily open up a web browser on said rooted device and access just fine via the web, but how long until services move away from web interfaces in favor of apps instead to assert more control?