Questions tagged [multi-factor]

a multi factor authentication requires at least two sets of credentials. This is typically something you know (e. g. a password) and something you own (e. g. a token generator or mobile phone), but could also be something you are (a biometric).

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130
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6answers
45k views

How secure are the FIDO U2F tokens

Google and Yubico just announced the availability of cryptographic security tokens following the FIDO U2F specification. Is this just another 2FA option, or is this significantly better than solutions ...
126
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8answers
60k views

How hard is it to intercept SMS (two-factor authentication)?

A lot of two-factor authentication mechanisms use SMS to deliver single-use passphrase to the user. So how secure is it? Is it hard to intercept the SMS message containing the passphrase? Do mobile ...
97
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7answers
17k views

Attacker circumventing 2FA. How to defend?

Detailed in the latest NSA dump is a method allegedly used by Russian intelligence to circumvent 2FA. (In this instance Google 2FA with the second factor being a code.) It’s a fairly obvious scheme ...
84
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2answers
18k views

How did someone log-in to my Gmail account from Kenya?

While on holiday in France in May I received an email from Google "New sign-in". Your Google Account was just used to sign in: Nairobi, Kenya. Tuesday, 26 May 2015 22:10 (East Africa Time). I ...
81
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5answers
12k views

Are texted 2FA security codes deliberately easy to remember?

I have 2FA setup on my bank account. When I login, I receive a six-digit code as an IM on my phone that I enter into the website. These codes always seem to have a pattern to them. Either something ...
65
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6answers
12k views

Four-factor authentication

I'm sure you've all heard of two-factor/multi-factor authentication. Basically it comes down to these factors: Knowledge - something you know (e.g. password, PIN, pattern) Possession - something you ...
64
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5answers
6k views

Do 2FA sites leak info by confirming a correct password guess?

Here's my relatively layman's view of the issue. Many websites tout multifactor authentication (MFA) as an enormous boost to the security of users' accounts, and it can be if implemented properly. ...
63
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6answers
9k views

Is 2FA via mobile phone still a good idea when phones are the most exposed device?

Everyone knows that two factors are better than one. My problem is that often the only second factor allowed is text messages sent to your mobile phone. This creates two concerns: I travel frequently ...
62
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2answers
9k views

How are one-time password generators like Google Authenticator different from having two passwords?

Google Authenticator uses the TOTP algorithm to generate your One-Time Password (OTP). TOTP works like this : The server generates a secret key and shares with the client (you) when the client ...
59
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9answers
56k views

Two-Step vs. Two-Factor Authentication - Is there a difference?

These days, there's pretty much three forms of authentication in general use on the web: Single-factor authentication, e.g.: PIN or password. Two-factor authentication, e.g.: Single-factor plus a ...
59
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5answers
31k views

What is a YubiKey and how does it work?

How do YubiKeys work? Are there any alternatives? Here is a picture of one:
51
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5answers
5k views

Should the average user with no special access rights be worried about SMS-based 2FA being theoretically interceptable?

Security experts are constantly discouraging users from using SMS-based 2FA systems, usually because of worries the auth code could be intercepted by an attacker, either through a SIM swap or a MitM ...
46
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8answers
10k views

Force user to remove USB token

I'm looking at setting up secure laptops using BitLocker with pre-boot PIN and startup key. I'm wondering if there is a way to force the user, who is remote, to remove the USB with the startup key ...
46
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7answers
8k views

Is an SSH key with a passphrase a 2FA?

This is a really theoretical question, but if I use an SSH key with a passphrase to login on a server, could this be considered as a two-factor authentication (2FA)? Indeed, I need the SSH (private) ...
42
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3answers
57k views

How does HSBC's “Secure Key” actually work?

My bank has recently sent me a Digipass/Secure Key, which looks like a tiny calculator. You press the green button to turn it on, type a PIN to unlock it, then press the green button again to generate ...
40
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2answers
7k views

Why does Google cripple the 2FA Google Authenticator PAM module?

If you enable 2FA for Google Apps the shared secret is 160 bits. The google_authenticator PAM module on the other hand seems to use 80 bits for the shared secret. According to RFC 4226: R6 - The ...
39
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11answers
8k views

Is it safe to use a weak password as long as I have two-factor authentication?

I'm careful to use strong passwords (according to How Big is Your Haystack, my passwords would take a massive cracking array 1.5 million centuries to crack), I don't reuse passwords across sites, and ...
35
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6answers
5k views

Should 2FA be enabled on service accounts?

See the title. I'm involved in a security audit right now, and am wondering whether 2FA should be enabled on not just human login accounts but also on service accounts (non-human accounts)? If so, how ...
35
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6answers
3k views

Why don't PGP and SSH keys see more widespread use as a second factor when authenticating?

One of the major up-and-coming MFA methods is U2F, which relies on an initial key exchange and challenge-response mechanism. It's a relatively new protocol, and is only starting to see more ...
31
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6answers
14k views

Why can't I share a one use code with anyone else?

I noticed in some cases when I get a verification code from Google it may say something along the line of: "You should not share this code with anyone else and no one from Google will ever ask for ...
31
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4answers
4k views

How is “something you have” typically defined for “two-factor” authentication?

A wide range of products claim to offer "two-factor authentication" (c.v. Two-factor authentication - Wikipedia). Most are deployed as "something you have" to be used in addition to a normal password ...
30
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4answers
8k views

How can a website verify that my phone number belongs to me?

I was signing into a Capital One credit card website that I hadn't used in a long time, and once I entered my user name and password, it requested my mobile phone number for additional verification. ...
28
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14answers
6k views

Why do we even use passwords / passphrases next to biometrics?

In the last couple of days there were a lot of talking about passwords and passphrases, not only here, but on several blogs and forums I follow (especially after XKCD #936 saw the light of this world)....
28
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3answers
2k views

How should disabling 2FA be handled by a service?

Due to personal reasons I recently had to disable and re-enable 2FA on quite a few of services. Now during this action I noticed quite a few different practices when it comes to "what should a user do ...
26
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3answers
7k views

Which SSH security is stronger? 2 Factor or Public key

For SSH authentication, which is more secure? 2 Factor Authentication using a USB token/Google Authenticator(time based) OR Public/private key with password Or could they be both used at the same ...
26
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2answers
27k views

How does Authy's 2FA work, if it doesn't connect to the server?

I thought I knew how two-factor authentication works: I enter the password. Server generates a random number (token) and sends it to me via SMS. I enter this token. Server checks that the token I ...
25
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2answers
9k views

What's the point of Microsoft Account 2FA if it still lets me log in using password instead?

I have a Microsoft Account linked to a Microsoft Authenticator app for 2FA purposes. Every time I log in, it first sends me the Authenticator request, but I can always click "Other ways to sign ...
25
votes
6answers
6k views

Why do apps with phone verification send the user a message, rather than have the user send one to them?

Many apps allow the user to authenticate with their phone number, by having the user enter it, and then sending an SMS with a code to be entered into the app. Very few (if any that I can find still ...
25
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1answer
14k views

What are the differences between the U2F and UAF FIDO authentication standards?

Google recently announced support for Universal 2nd Factor (U2F) authentication in Chrome and started allowing that authentication mechanism to be used for 2-factor authentication across their various ...
25
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3answers
5k views

How to securely store and manage one-time backup codes for 2FA?

I am already using 31 services with 2nd factor authentication and the number is growing. In addition to having multiple authentication devices, I decided for or had to generate a separate set of one-...
24
votes
4answers
994 views

Bank asked for a cross login?

I was creating a new bank account here in the US at HSBC's popular online bank... You know the step where you have to verify the account you're sending from, by receiving two small test payments? I ...
23
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6answers
5k views

Is it safe to store 2FA tokens together with passwords in 1password?

I'm using 1password and I've seen 1password allows you to store 2FA tokens in the same place where you store the password. I don't like the idea of having everything in the same place as if someone ...
23
votes
4answers
4k views

What is the risk and mitigation of accidentally typing a YubiKey password in an open forum?

I have a YubiKey in my laptop (for testing) and accidentally broadcast my YubiKey password out to the Internet. Since this is only a test key, and has no access to anything of value, here are some ...
22
votes
2answers
6k views

What is the risk of having a 2FA key permanently plugged into my device?

Yubico offers the YubiKey Nano, a 2FA key designed to be left inside the device more or less permanently. While it does add comfort to be able to just leave it plugged in, what risks would there be ...
22
votes
6answers
8k views

Is tokenless (specifically SMS) 2FA a security compromise over OTP tokens?

I've been looking into the various pros/cons of tokenless (particularly SMS based) and traditional token based two-factor authentication (think RSA SecurID). After doing some research, I think I have ...
21
votes
4answers
8k views

Why use a Smartcard for (Two Factor) Auth instead of another medium?

I recently installed Bitlocker on my Windows 8.1 machine, using only a password. I was thinking of getting something other than just a password for my storage drive, something physical, like a USB, SD ...
21
votes
4answers
21k views

Does adding two-factor authentication by OTP really make KeePass more secure

KeePass is an application that keeps all your passwords for you in a database. It is primarily protected by a master password and/or keyfile. If the database is properly encrypted with that password ...
20
votes
6answers
4k views

What extra security does a 2-step website login process with a PIN provide?

I am currently working on a web application with a significant security risk attached to its function. We're using Microsoft Identity Framework to handle user logins, with the system forcing strong ...
20
votes
4answers
3k views

Biometric versus other Two Factor Authentication Mechanisms

Over the years biometrics is the go-to movie authentication mechanism, but in the real world I'm getting conflicting opinions about it. Everything I've learned shows that biometrics are flawed ...
19
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11answers
5k views

2 factor authentication - cost effective solution for a web startup [closed]

My local bank uses a 2 factor authentication where customers key in password AND a One Time PIN delivered via SMS to mobile phone OR from a security token device. I am doing a web startup in the ...
19
votes
4answers
4k views

In a “card not present” transaction, is the credit card number, expiry date & CVV considered as a “What you have” or a “What you know”?

Is the credit card number, CVV & expiry date considered to be a secret? If so, then the physical credit card is incidental & the info about the card is something "you know". OTOH, if you don't ...
17
votes
3answers
2k views

Multi factor authentication on Ubuntu workstations, where to start?

Is it possible to have Ubuntu users log in with multi-factor authentication? I was thinking of a combination of pass(word|code) and smartcard (with screen locks when for example smart-card is removed) ...
17
votes
1answer
6k views

Storing TOTP secret in database, plaintext or encrypted?

I've been reading about 2FA and how it is used, and the thing that struck me most is that everyone seems to be storing the TOTP secret as plaintext in their database. I understand you need the secret ...
16
votes
2answers
5k views

Is there a way to prevent hackers from using cookies to bypass two step verification?

Let's take Steam/Google/FB/Microsoft/Twitter logins as examples. All of them offer two step verification through SMS message. Let's say the hacker does not have access to my phone. But he has access ...
16
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5answers
2k views

Does two factor authentication prevent social engineering attacks

After reading this article from symantec I got to think how much all these social engineering techniques rely on the authentication system of users, a password. Considering three different additional ...
16
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4answers
6k views

What is the use of the “secret” displayed when setting up 2 Factor Authentication?

What is the purpose of the "secret" that is displayed when you take the picture of the QR code to set up 2 Factor Authentication on a non-Google site? Why would you need it? If you save it, doesn't ...
16
votes
6answers
13k views

How to implement multi factor authentication using a token generator?

I'd like to implement multi factor authentication on a few projects. Now the first factor would be username and password, for the second factor I would like to use a token generator. These tokens ...
16
votes
4answers
6k views

Three-Factor Authentication for Windows

This HowToGeek article... http://www.howtogeek.com/67556/how-to-unlock-your-pc-by-being-nearby-with-a-bluetooth-phone/ ...got me thinking. Is there any software (or combination of software) that ...
16
votes
2answers
11k views

How does Google detect new devices for two factor authentication

When you enable two step verification for google accounts, you get sent a code by SMS to enter in addition to your username and password the first time you log in with a new device. How do they ...
16
votes
2answers
759 views

Mitigating the loss of a mobile phone used for second-factor login

Take the following scenario: John is using GMail for his primary email account and LastPass as his password management system. Both of these accounts are using the Google Authenticator mobile ...

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