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No, I understand that. Let me simplify my point: Whether or not the TOTP secret is on the smartphone, encrypted or not, or sent to it from another device, is t

by dsacco 10y ago

No, I understand that. Let me simplify my point: Whether or not the TOTP secret is on the smartphone, encrypted or not, or sent to it from another device, is the wrong attack vector to optimize for. Getting mainstream users en masse to consistently and correctly use any 2fa is a win. Furthermore, you're moving the goalposts a bit by using the Yubikey in this scenario. So sure, if someone compromises your phone they don't compromise the Yubikey, but 1) how certain are you that your Yubikey is safer than a modern iPhone or Android model with the crypto and security engineering that entails and 2) how certain are you that accessing your iPhone's filesystem or execution state does not bypass this whole dance entirely? For you, the minimal security gains might outweigh the usability costs if you know what you're doing. But a hardware token for most people, as the technology currently stands?

lrvick 10y ago
The device keeps the secret in self contained memory and never exposes it. It is on the other side of a USB bus or in some cases NFC. There have been local attacks against old designs via side channel attacks etc, but never once a remote attack. The model makes that pretty hard. The phone is essentially zero knowledge. Android and iOS allow arbitrary execution of user installed code and are a massive attack surface and have piles of pubished vulnerabilities. By moving secrets to very simple easy to reason about devices we get substantial reduction in attack surface. Also I have helped deploy these to several dozen people, taught workshops etc. It is no harder than teaching people to use Google Authenticator, but lower attack surface. Use U2F where you can and when you must fall back to TOTP at least you can promise an attacker does not get a free pass to genreate codes whenever they want which is something.
chiefalchemist 10y ago
Getting mainstream users to use 2FA? Is that like getting them not to use overly simple PWs? Or not use open wifi? Those people?make Not sound like an ahole but...How's that working out for ya? I think ya might be able to argue that if you're going to add friction (e.g., Yubikey) you're also creating a great senses of seriousness. That sense of seriousness is seriously lacking. All that said, the UN + PW idea is too weak. We need something that's up to the threat AND is also appropriate to the risk of loss. Best I can tell, as a general mainstream rule, we're not even close to that. It's 2017? Really?

by dsacco 10y ago

lrvick 10y ago

The device keeps the secret in self contained memory and never exposes it. It is on the other side of a USB bus or in some cases NFC. There have been local attacks against old designs via side channel attacks etc, but never once a remote attack. The model makes that pretty hard. The phone is essentially zero knowledge. Android and iOS allow arbitrary execution of user installed code and are a massive attack surface and have piles of pubished vulnerabilities. By moving secrets to very simple easy to reason about devices we get substantial reduction in attack surface. Also I have helped deploy these to several dozen people, taught workshops etc. It is no harder than teaching people to use Google Authenticator, but lower attack surface. Use U2F where you can and when you must fall back to TOTP at least you can promise an attacker does not get a free pass to genreate codes whenever they want which is something.

chiefalchemist 10y ago

Getting mainstream users to use 2FA? Is that like getting them not to use overly simple PWs? Or not use open wifi? Those people?make Not sound like an ahole but...How's that working out for ya? I think ya might be able to argue that if you're going to add friction (e.g., Yubikey) you're also creating a great senses of seriousness. That sense of seriousness is seriously lacking. All that said, the UN + PW idea is too weak. We need something that's up to the threat AND is also appropriate to the risk of loss. Best I can tell, as a general mainstream rule, we're not even close to that. It's 2017? Really?