Entries Tagged "two-factor authentication"

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Credit Card Fraud That Bypasses 2FA

Someone in the UK is stealing smartphones and credit cards from people who have stored them in gym lockers, and is using the two items in combination to commit fraud:

Phones, of course, can be made inaccessible with the use of passwords and face or fingerprint unlocking. And bank cards can be stopped.

But the thief has a method which circumnavigates those basic safety protocols.

Once they have the phone and the card, they register the card on the relevant bank’s app on their own phone or computer. Since it is the first time that card will have been used on the new device, a one-off security passcode is demanded.

That verification passcode is sent by the bank to the stolen phone. The code flashes up on the locked screen of the stolen phone, leaving the thief to tap it into their own device. Once accepted, they have control of the bank account. They can transfer money or buy goods, or change access to the account.

Posted on September 20, 2022 at 6:29 AMView Comments

Man-in-the-Middle Phishing Attack

Here’s a phishing campaign that uses a man-in-the-middle attack to defeat multi-factor authentication:

Microsoft observed a campaign that inserted an attacker-controlled proxy site between the account users and the work server they attempted to log into. When the user entered a password into the proxy site, the proxy site sent it to the real server and then relayed the real server’s response back to the user. Once the authentication was completed, the threat actor stole the session cookie the legitimate site sent, so the user doesn’t need to be reauthenticated at every new page visited. The campaign began with a phishing email with an HTML attachment leading to the proxy server.

Posted on August 25, 2022 at 6:45 AMView Comments

When Security Locks You Out of Everything

Thought experiment story of someone who lost everything in a house fire, and now can’t log into anything:

But to get into my cloud, I need my password and 2FA. And even if I could convince the cloud provider to bypass that and let me in, the backup is secured with a password which is stored in—you guessed it—my Password Manager.

I am in cyclic dependency hell. To get my passwords, I need my 2FA. To get my 2FA, I need my passwords.

It’s a one-in-a-million story, and one that’s hard to take into account in system design.

This is where we reach the limits of the “Code Is Law” movement.

In the boring analogue world—I am pretty sure that I’d be able to convince a human that I am who I say I am. And, thus, get access to my accounts. I may have to go to court to force a company to give me access back, but it is possible.

But when things are secured by an unassailable algorithm—I am out of luck. No amount of pleading will let me without the correct credentials. The company which provides my password manager simply doesn’t have access to my passwords. There is no-one to convince. Code is law.

Of course, if I can wangle my way past security, an evil-doer could also do so.

So which is the bigger risk?

  • An impersonator who convinces a service provider that they are me?
  • A malicious insider who works for a service provider?
  • Me permanently losing access to all of my identifiers?

I don’t know the answer to that.

Those risks are in the order of most common to least common, but that doesn’t necessarily mean that they are in risk order. They probably are, but then we’re left with no good way to handle someone who has lost all their digital credentials—computer, phone, backup, hardware token, wallet with ID cards—in a catastrophic house fire.

I want to remind readers that this isn’t a true story. It didn’t actually happen. It’s a thought experiment.

Posted on June 28, 2022 at 6:22 AMView Comments

Bypassing Two-Factor Authentication

These techniques are not new, but they’re increasingly popular:

…some forms of MFA are stronger than others, and recent events show that these weaker forms aren’t much of a hurdle for some hackers to clear. In the past few months, suspected script kiddies like the Lapsus$ data extortion gang and elite Russian-state threat actors (like Cozy Bear, the group behind the SolarWinds hack) have both successfully defeated the protection.

[…]

Methods include:

  • Sending a bunch of MFA requests and hoping the target finally accepts one to make the noise stop.
  • Sending one or two prompts per day. This method often attracts less attention, but “there is still a good chance the target will accept the MFA request.”
  • Calling the target, pretending to be part of the company, and telling the target they need to send an MFA request as part of a company process.

FIDO2 multi-factor authentication systems are not susceptible to these attacks, because they are tied to a physical computer.

And even though there are attacks against these two-factor systems, they’re much more secure than not having them at all. If nothing else, they block pretty much all automated attacks.

Posted on April 1, 2022 at 6:12 AMView Comments

Problems with Multifactor Authentication

Roger Grimes on why multifactor authentication isn’t a panacea:

The first time I heard of this issue was from a Midwest CEO. His organization had been hit by ransomware to the tune of $10M. Operationally, they were still recovering nearly a year later. And, embarrassingly, it was his most trusted VP who let the attackers in. It turns out that the VP had approved over 10 different push-based messages for logins that he was not involved in. When the VP was asked why he approved logins for logins he was not actually doing, his response was, “They (IT) told me that I needed to click on Approve when the message appeared!”

And there you have it in a nutshell. The VP did not understand the importance (“the WHY”) of why it was so important to ONLY approve logins that they were participating in. Perhaps they were told this. But there is a good chance that IT, when implementinthe new push-based MFA, instructed them as to what they needed to do to successfully log in, but failed to mention what they needed to do when they were not logging in if the same message arrived. Most likely, IT assumed that anyone would naturally understand that it also meant not approving unexpected, unexplained logins. Did the end user get trained as to what to do when an unexpected login arrived? Were they told to click on “Deny” and to contact IT Help Desk to report the active intrusion?

Or was the person told the correct instructions for both approving and denying and it just did not take? We all have busy lives. We all have too much to do. Perhaps the importance of the last part of the instructions just did not sink in. We can think we hear and not really hear. We can hear and still not care.

Posted on October 21, 2021 at 6:25 AMView Comments

Cloning Google Titan 2FA keys

This is a clever side-channel attack:

The cloning works by using a hot air gun and a scalpel to remove the plastic key casing and expose the NXP A700X chip, which acts as a secure element that stores the cryptographic secrets. Next, an attacker connects the chip to hardware and software that take measurements as the key is being used to authenticate on an existing account. Once the measurement-taking is finished, the attacker seals the chip in a new casing and returns it to the victim.

Extracting and later resealing the chip takes about four hours. It takes another six hours to take measurements for each account the attacker wants to hack. In other words, the process would take 10 hours to clone the key for a single account, 16 hours to clone a key for two accounts, and 22 hours for three accounts.

By observing the local electromagnetic radiations as the chip generates the digital signatures, the researchers exploit a side channel vulnerability in the NXP chip. The exploit allows an attacker to obtain the long-term elliptic curve digital signal algorithm private key designated for a given account. With the crypto key in hand, the attacker can then create her own key, which will work for each account she targeted.

The attack isn’t free, but it’s not expensive either:

A hacker would first have to steal a target’s account password and also gain covert possession of the physical key for as many as 10 hours. The cloning also requires up to $12,000 worth of equipment and custom software, plus an advanced background in electrical engineering and cryptography. That means the key cloning—­were it ever to happen in the wild—­would likely be done only by a nation-state pursuing its highest-value targets.

That last line about “nation-state pursuing its highest-value targets” is just not true. There are many other situations where this attack is feasible.

Note that the attack isn’t against the Google system specifically. It exploits a side-channel attack in the NXP chip. Which means that other systems are probably vulnerable:

While the researchers performed their attack on the Google Titan, they believe that other hardware that uses the A700X, or chips based on the A700X, may also be vulnerable. If true, that would include Yubico’s YubiKey NEO and several 2FA keys made by Feitian.

Posted on January 12, 2021 at 6:16 AMView Comments

How the SolarWinds Hackers Bypassed Duo’s Multi-Factor Authentication

This is interesting:

Toward the end of the second incident that Volexity worked involving Dark Halo, the actor was observed accessing the e-mail account of a user via OWA. This was unexpected for a few reasons, not least of which was the targeted mailbox was protected by MFA. Logs from the Exchange server showed that the attacker provided username and password authentication like normal but were not challenged for a second factor through Duo. The logs from the Duo authentication server further showed that no attempts had been made to log into the account in question. Volexity was able to confirm that session hijacking was not involved and, through a memory dump of the OWA server, could also confirm that the attacker had presented cookie tied to a Duo MFA session named duo-sid.

Volexity’s investigation into this incident determined the attacker had accessed the Duo integration secret key (akey) from the OWA server. This key then allowed the attacker to derive a pre-computed value to be set in the duo-sid cookie. After successful password authentication, the server evaluated the duo-sid cookie and determined it to be valid. This allowed the attacker with knowledge of a user account and password to then completely bypass the MFA set on the account. It should be noted this is not a vulnerability with the MFA provider and underscores the need to ensure that all secrets associated with key integrations, such as those with an MFA provider, should be changed following a breach.

Again, this is not a Duo vulnerability. From ArsTechnica:

While the MFA provider in this case was Duo, it just as easily could have involved any of its competitors. MFA threat modeling generally doesn’t include a complete system compromise of an OWA server. The level of access the hacker achieved was enough to neuter just about any defense.

Posted on December 15, 2020 at 2:13 PMView Comments

Zoom Will Be End-to-End Encrypted for All Users

Zoom is doing the right thing: it’s making end-to-end encryption available to all users, paid and unpaid. (This is a change; I wrote about the initial decision here.)

…we have identified a path forward that balances the legitimate right of all users to privacy and the safety of users on our platform. This will enable us to offer E2EE as an advanced add-on feature for all of our users around the globe—free and paid—while maintaining the ability to prevent and fight abuse on our platform.

To make this possible, Free/Basic users seeking access to E2EE will participate in a one-time process that will prompt the user for additional pieces of information, such as verifying a phone number via a text message. Many leading companies perform similar steps on account creation to reduce the mass creation of abusive accounts. We are confident that by implementing risk-based authentication, in combination with our current mix of tools—including our Report a User function—we can continue to prevent and fight abuse.

Thank you, Zoom, for coming around to the right answer.

And thank you to everyone for commenting on this issue. We are learning—in so many areas—the power of continued public pressure to change corporate behavior.

EDITED TO ADD (6/18): Let’s do Apple next.

Posted on June 17, 2020 at 1:55 PMView Comments

Chinese Hackers Bypassing Two-Factor Authentication

Interesting story of how a Chinese state-sponsored hacking group is bypassing the RSA SecurID two-factor authentication system.

How they did it remains unclear; although, the Fox-IT team has their theory. They said APT20 stole an RSA SecurID software token from a hacked system, which the Chinese actor then used on its computers to generate valid one-time codes and bypass 2FA at will.

Normally, this wouldn’t be possible. To use one of these software tokens, the user would need to connect a physical (hardware) device to their computer. The device and the software token would then generate a valid 2FA code. If the device was missing, the RSA SecureID software would generate an error.

The Fox-IT team explains how hackers might have gone around this issue:

The software token is generated for a specific system, but of course this system specific value could easily be retrieved by the actor when having access to the system of the victim.

As it turns out, the actor does not actually need to go through the trouble of obtaining the victim’s system specific value, because this specific value is only checked when importing the SecurID Token Seed, and has no relation to the seed used to generate actual 2-factor tokens. This means the actor can actually simply patch the check which verifies if the imported soft token was generated for this system, and does not need to bother with stealing the system specific value at all.

In short, all the actor has to do to make use of the 2 factor authentication codes is to steal an RSA SecurID Software Token and to patch 1 instruction, which results in the generation of valid tokens.

Posted on December 26, 2019 at 6:19 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.