theDocumentId => 1331835 Cracking 2FA: How It's Done and How to Stay Safe

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5/17/2018
05:42 PM
Kelly Sheridan
Kelly Sheridan
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Cracking 2FA: How It's Done and How to Stay Safe

Two-factor authentication is a common best security practice but not ironclad. Here's how it can be bypassed, and how you can improve security.
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Phishing Emails
This is the most common way of cracking two-factor authentication, Manzuik says, but it's not as simple as spamming an entire organization with malware. You can't simply send a mass email and wait for someone to click the link. Bypassing 2FA is sneakier and more intensive.
'It relies on the user to not be suspicious in any way,' he adds.
Hackers need to know their targets: who they are, how they're using two-factor, and where they're located. The phishing email needs to convince the target they're logging into a legitimate portal. For example, if a target is using a one-time passcode as 2FA for their Gmail account, the attacker would have to know so they can duplicate the login page and convince the person to enter their username and password.
While timing depends on the attacker, Manzuik says it makes the most sense for them to act during the workday because it's when people expect to receive one-time codes. If they're prompted for a two-factor code in the middle of the night, targets will be suspicious.
For phishing one-time passcodes, timing is crucial. When the user receives the passcode it has to be valid long enough to them to use it. But the timing is only critical for access: once an attacker collects credentials and gains access, they can sit on the network, move across it, or use their position within the company to target the victim's friends or colleagues.
(Image: wk1003mike via Shutterstock)

Phishing Emails

This is the most common way of cracking two-factor authentication, Manzuik says, but it's not as simple as spamming an entire organization with malware. You can't simply send a mass email and wait for someone to click the link. Bypassing 2FA is sneakier and more intensive.

"It relies on the user to not be suspicious in any way," he adds.

Hackers need to know their targets: who they are, how they're using two-factor, and where they're located. The phishing email needs to convince the target they're logging into a legitimate portal. For example, if a target is using a one-time passcode as 2FA for their Gmail account, the attacker would have to know so they can duplicate the login page and convince the person to enter their username and password.

While timing depends on the attacker, Manzuik says it makes the most sense for them to act during the workday because it's when people expect to receive one-time codes. If they're prompted for a two-factor code in the middle of the night, targets will be suspicious.

For phishing one-time passcodes, timing is crucial. When the user receives the passcode it has to be valid long enough to them to use it. But the timing is only critical for access: once an attacker collects credentials and gains access, they can sit on the network, move across it, or use their position within the company to target the victim's friends or colleagues.

(Image: wk1003mike via Shutterstock)

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williamconor
50%
50%
williamconor,
User Rank: Apprentice
9/17/2018 | 11:14:11 AM
Cracking the SS7 Network
NIST, the National Institute of Standards and Technology issued guidance that found SMS insecure and no longer suitable as a strong authentication mechanism...

I am using WebADM Multi-Factor Authentication with Hardware Token (U2F) and Hardware Security Modules (HSM) in order to comply with the highest security requirements...

This Security Solution from RCDevs is like a Swiss Army Knife.

It is even free up to 40 users.
NeverEnoughToys
100%
0%
NeverEnoughToys,
User Rank: Apprentice
5/23/2018 | 4:07:11 PM
That's not really cracking 2FA
Most of these aren't about cracking 2FA.  They are about bypassing 2FA.  The SS7 and SMS type examples could be argued as cracking, but they are really about breaking into SS7/SMS - the 2FA compromise is simply a welcome result or side effect. 

SMS is not secure and should never have been used for 2FA, but convenience wins (as the article points out).  Time based generators are much more secure (yep, and less convenient).
RyanSepe
0%
100%
RyanSepe,
User Rank: Ninja
5/21/2018 | 10:18:28 AM
Phishing
As a Security Engineer, I always stress the dangers of phishing and this is a perfect example as to why. It subverts most of the security safeguards at an organization with minimal effort as it exploits an open medium. This is why there has been a very steady transition from server side attacks to client side attacks. 
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