
Hackers Make a Fake Hand to Beat Vein Authentication - pseudolus
https://motherboard.vice.com/en_us/article/59v8dk/hackers-fake-hand-vein-authentication-biometrics-chaos-communication-congress
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tbabb
Why are we still trying to do biometric security?

\- Biometrics are public, unlike passwords. Biometric data can usually be
gathered from a person, often discreetly, by cameras or whatever other sensors
are used for authentication, and replayed with sufficient effort to fool the
same sensors.

\- Biometrics are not revokable, unlike passwords. If you give your biometric
data to someone and they mishandle it, it's compromised for life.

\- Biometrics cannot be uniquified for different authenticators, which is like
using the same password for every service-- terribly insecure.

\- Biometrics pose secondary privacy concerns, because they inherently destroy
anonymity.

Why is this still a thing?

~~~
FakeComments
Because in most people’s threat models, it’s still a win.

Biometrics do three things:

\- It greatly reduces the friction of “showing” who you are.

\- It moves the mechanism into an “off-main-CPU” chip, while the main CPU just
sees limited APIs, and strong crypto which _can_ be rekeyed. You can’t rekey
your bio-signature, but this architecture is better in a number of ways.

\- It creates a non-digital interaction as part of the auth flow.

I personally subscribe to somewhere between “not a wrench” and “not Mossad”
security: most things I’ll tell anyone who will hit me with a $20 wrench, and
I’m definitely not in the business of trying to stop Mossad reading my papers.

From that perspective, my security doesn’t need to be better than biometric on
almost anything, because that’s good enough to make a wrench (or a warrant) a
cheaper option — so I don’t care there are exotic attacks like copying my vein
pattern, printing a fake hand, and touching things.

It also stops my main concern from the government: warrantless mass-
surveillance. There’s a scaling limit on using fake vein prints to break into
things. And the non-digital step forces an actual interaction.

Frequent, low-friction requests also allows for minimizing credential caching
and for non-digital requests for confirmation before proceeding. This helps a
lot against malware and escalation attacks.

Note: every power cycle and few days, as well as “major” actions, I have to
use an actual password — I mind this less precisely because I don’t have to
use it as often. So the biometrics are also only a low credential auth when
the device is already authenticated through a better mechanism. Is this
perfect? No. But again, it’s a numbers game.

So in most people’s usage, biometrics are a huge solution to a tricky set of
trade offs, while even in the really secure setting that you’re worried about
fake hands, it remains a useful part of multi-factor because fake hands are
complicated to make and deploy.

~~~
marcosdumay
> It creates a non-digital interaction as part of the auth flow.

Well, that's not correct. You may have an analogical sensor somewhere to
collect the data, but all the data, communication and storage is still
digital. You can always bypass the data collection.

~~~
FakeComments
You can’t digitally do so, no.

You would have to physically interact with the device to change how the
circuit operated, or else the only way for the CPU to access the cryptographic
data is by allowing a different specialized circuit to unlock a value based on
analog input.

You can’t meaningfully “bypass” that digitally, unless you already know the
secret. So if the auth flow depends on that secret, it can’t bypass the analog
sensor feeding in the values to unlock it.

The bypasses we see are where you can, eg, attach a debug cable to feed in
values without going through the sensor (which is a non-digital interaction).
Or bugs in correctly implementing the logic, eg, the crypto chip accidentally
exposes information.

It’s much the same protection a yubikey left in the side of your laptop
provides: someone physically at the device pushed a button, with a
cryptographic witness that’s hard to fake.

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grumdan
While biometric authentication is overall less secure and can be circumvented,
I still think there are situations where it's preferable to the alternatives,
in particular on smartphones:

All Android versions I used don't support setting an encryption passphrase
that's separate from the unlock pin/password. As a result one has to choose
between a very long unlock password one has to enter all the time or a
convenient short one making encryption basically useless. Given this trade-
off, I think using a proper, long passphrase for encryption with a fingerprint
for normal unlocks is preferable to the alternatives. It's particularly
irritating that this restriction is not at all technical; the only
justifications I've read were along the lines of "it might confuse users".

Less importantly, for my phone, a shoulder-surfing attack seems much more
likely to me than someone specifically copying my fingerprint.

~~~
imron
On the flip side, anyone who obtains the physical device likely has access to
the key (your fingerprints are all over it)

~~~
grumdan
That's true, though at this point against a sophisticated attacker, it might
be game over anyway, since they could read out the encryption key from RAM
directly if it's still turned on. If the device is off, the fingerprints won't
help and the data is protected by the long passphrase.

Of course all this assumes a particular attacker model and for a lazy attacker
that doesn't know how to use the fingerprints to fool the sensor, everything
is fine.

Another downside is being possibly forced to unlock my phone at airports,
since as far as I'm aware, passwords are protected by the fifth amendment
whereas fingerprints are not. In this case it might be smarter to turn off
one's phone entirely when crossing borders into countries where one can be
compelled in this way. This doesn't even go into all the other kinds of
pressure they might apply to make me unlock my phone anyway though, so there's
not much protection here aside from leaving my good phone at home.

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theandrewbailey
> "Biometrics is always an arm race," Krissler said.

No kidding. They might have to fake an entire arm soon!

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mitchs
My thinking has always been that unsupervised biometrics are just a weird form
of "something you know." Only when you put a human there to make sure there is
no funny business during data entry doors it become "something you are."

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lawl
Actual talk for anyone interested:

[https://media.ccc.de/v/35c3-9545-venenerkennung_hacken](https://media.ccc.de/v/35c3-9545-venenerkennung_hacken)

Talk is in german, but if you click the cog on the bottom right there's an
english translation.

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walrus01
Once again proving that biometric authentication is not a replacement for
public/private key cryptography. Biometrics are in fact worse than just
passwords, because you can't change the authenticating credential.

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Spivak
Really cool demonstration but I don't think it should really surprise anyone.
You couldn't really fool a human checking fingerprints because a human has the
ability to validate that they're checking the finger of an actual human.

So forget all the fancy ways of encoding our biology into unique patterns.
Unless the system can detect that it's reading the arm of an actual human
being we're always going to be vulnerable to this kind of attack.

~~~
Santosh83
How do you address identity theft when biometrics becomes the norm? Thus far
you can always say your ID credentials were stolen/duplicated.

But in future, good luck trying to convince law enforcement that your
fingerprints, your iris patterns, your physiognomy and your DNA were stolen
too.

~~~
yholio
That's the major appeal of biometrics, the user is considered an attacker,
either by knowingly transmitting his credentials or getting dupped into it.

Biometrics restore the illusion of control to the designer, they now have the
luxury of no longer caring about user behaviour, it is just a body moving
through the system. Except biometrics doesn't work.

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pkzip
I believe only in behavioural "biometrics" which combines knowledge and
inference together with zero knowledge proof to locally authenticate users on
their personal and probably secure devices. Any other attempts in using
biometrics are futile.

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saalweachter
Something something, Goodhart's Law.

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raws
2500 pics required for now.

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paul7986
Is there a fake/robotic hand I can buy to swipe right on every profile on
Tinder and okCupid?

This way I dont do any work nor know those i swiped right on didnt swipe back.
I only learn of all those who swiped right then I filter through and start
conversations.

~~~
int_x
I think Tinder has some sort of algorithm in place to punish you for swiping
right on everyone. Probably not a good idea if you want to get matches

~~~
hashhar
I think it's based on elo scores.

[https://en.m.wikipedia.org/wiki/Elo_rating_system](https://en.m.wikipedia.org/wiki/Elo_rating_system)

