Entries Tagged "authentication"

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Credential Stealing as an Attack Vector

Traditional computer security concerns itself with vulnerabilities. We employ antivirus software to detect malware that exploits vulnerabilities. We have automatic patching systems to fix vulnerabilities. We debate whether the FBI should be permitted to introduce vulnerabilities in our software so it can get access to systems with a warrant. This is all important, but what’s missing is a recognition that software vulnerabilities aren’t the most common attack vector: credential stealing is.

The most common way hackers of all stripes, from criminals to hacktivists to foreign governments, break into networks is by stealing and using a valid credential. Basically, they steal passwords, set up man-in-the-middle attacks to piggy-back on legitimate logins, or engage in cleverer attacks to masquerade as authorized users. It’s a more effective avenue of attack in many ways: it doesn’t involve finding a zero-day or unpatched vulnerability, there’s less chance of discovery, and it gives the attacker more flexibility in technique.

Rob Joyce, the head of the NSA’s Tailored Access Operations (TAO) group—basically the country’s chief hacker—gave a rare public talk at a conference in January. In essence, he said that zero-day vulnerabilities are overrated, and credential stealing is how he gets into networks: “A lot of people think that nation states are running their operations on zero days, but it’s not that common. For big corporate networks, persistence and focus will get you in without a zero day; there are so many more vectors that are easier, less risky, and more productive.”

This is true for us, and it’s also true for those attacking us. It’s how the Chinese hackers breached the Office of Personnel Management in 2015. The 2014 criminal attack against Target Corporation started when hackers stole the login credentials of the company’s HVAC vendor. Iranian hackers stole US login credentials. And the hacktivist that broke into the cyber-arms manufacturer Hacking Team and published pretty much every proprietary document from that company used stolen credentials.

As Joyce said, stealing a valid credential and using it to access a network is easier, less risky, and ultimately more productive than using an existing vulnerability, even a zero-day.

Our notions of defense need to adapt to this change. First, organizations need to beef up their authentication systems. There are lots of tricks that help here: two-factor authentication, one-time passwords, physical tokens, smartphone-based authentication, and so on. None of these is foolproof, but they all make credential stealing harder.

Second, organizations need to invest in breach detection and—most importantly—incident response. Credential-stealing attacks tend to bypass traditional IT security software. But attacks are complex and multi-step. Being able to detect them in process, and to respond quickly and effectively enough to kick attackers out and restore security, is essential to resilient network security today.

Vulnerabilities are still critical. Fixing vulnerabilities is still vital for security, and introducing new vulnerabilities into existing systems is still a disaster. But strong authentication and robust incident response are also critical. And an organization that skimps on these will find itself unable to keep its networks secure.

This essay originally appeared on Xconomy.

EDITED TO ADD (5/23): Portuguese translation.

Posted on May 4, 2016 at 6:51 AM • View Comments

Determining Physical Location on the Internet

Interesting research: “CPV: Delay-based Location Verification for the Internet“:

Abstract: The number of location-aware services over the Internet continues growing. Some of these require the client’s geographic location for security-sensitive applications. Examples include location-aware authentication, location-aware access policies, fraud prevention, complying with media licensing, and regulating online gambling/voting. An adversary can evade existing geolocation techniques, e.g., by faking GPS coordinates or employing a non-local IP address through proxy and virtual private networks. We devise Client Presence Verification (CPV), a delay-based verification technique designed to verify an assertion about a device’s presence inside a prescribed geographic region. CPV does not identify devices by their IP addresses. Rather, the device’s location is corroborated in a novel way by leveraging geometric properties of triangles, which prevents an adversary from manipulating measured delays. To achieve high accuracy, CPV mitigates Internet path asymmetry using a novel method to deduce one-way application-layer delays to/from the client’s participating device, and mines these delays for evidence supporting/refuting the asserted location. We evaluate CPV through detailed experiments on PlanetLab, exploring various factors that affect its efficacy, including the granularity of the verified location, and the verification time. Results highlight the potential of CPV for practical adoption.

News articles.

Posted on February 12, 2016 at 6:19 AM • View Comments

The Doxing Trend

If the director of the CIA can’t keep his e-mail secure, what hope do the rest of us have—for our e-mail or any of our digital information?

None, and that’s why the companies that we entrust with our digital lives need to be required to secure it for us, and held accountable when they fail. It’s not just a personal or business issue; it’s a matter of public safety.

The details of the story are worth repeating. Someone, reportedly a teenager, hacked into CIA Director John O. Brennan’s AOL account. He says he did so by posing as a Verizon employee to Verizon to get personal information about Brennan’s account, as well as his bank card number and his AOL e-mail address. Then he called AOL and pretended to be Brennan. Armed with the information he got from Verizon, he convinced AOL customer service to reset his password.

The CIA director did nothing wrong. He didn’t choose a lousy password. He didn’t leave a copy of it lying around. He didn’t even send it in e-mail to the wrong person. The security failure, according to this account, was entirely with Verizon and AOL. Yet still Brennan’s e-mail was leaked to the press and posted on WikiLeaks.

This kind of attack is not new. In 2012, the Gmail and Twitter accounts of Wired writer Mat Honan were taken over by a hacker who first persuaded Amazon to give him Honan’s credit card details, then used that information to hack into his Apple ID account, and finally used that information to get into his Gmail account.

For most of us, our primary e-mail account is the “master key” to every one of our other accounts. If we click on a site’s “forgot your password?” link, that site will helpfully e-mail us a special URL that allows us to reset our password. That’s how Honan’s hacker got into his Twitter account, and presumably Brennan’s hacker could have done the same thing to any of Brennan’s accounts.

Internet e-mail providers are trying to beef up their authentication systems. Yahoo recently announced it would do away with passwords, instead sending a one-time authentication code to the user’s smartphone. Google has long had an optional two-step authentication system that involves sending a one-time code to the user via phone call or SMS.

You might think cell phone authentication would thwart these attacks. Even if a hacker persuaded your e-mail provider to change your password, he wouldn’t have your phone and couldn’t obtain the one-time code. But there’s a way to beat this, too. Indie developer Grant Blakeman’s Gmail account was hacked last year, even though he had that extra-secure two-step system turned on. The hackers persuaded his cell phone company to forward his calls to another number, one controlled by the hackers, so they were able to get the necessary one-time code. And from Google, they were able to reset his Instagram password.

Brennan was lucky. He didn’t have anything classified on his AOL account. There were no personal scandals exposed in his email. Yes, his 47-page top-secret clearance form was sensitive, but not embarrassing. Honan was less lucky, and lost irreplaceable photographs of his daughter.

Neither of them should have been put through this. None of us should have to worry about this.

The problem is a system that makes this possible, and companies that don’t care because they don’t suffer the losses. It’s a classic market failure, and government intervention is how we have to fix the problem.

It’s only when the costs of insecurity exceed the costs of doing it right that companies will invest properly in our security. Companies need to be responsible for the personal information they store about us. They need to secure it better, and they need to suffer penalties if they improperly release it. This means regulatory security standards.

The government should not mandate how a company secures our data; that will move the responsibility to the government and stifle innovation. Instead, government should establish minimum standards for results, and let the market figure out how to do it most effectively. It should allow individuals whose information has been exposed sue for damages. This is a model that has worked in all other aspects of public safety, and it needs to be applied here as well.

We have a role to play in this, too. One of the reasons security measures are so easy to bypass is that we as consumers demand they be easy to use, and easy for us to bypass if we lose or forget our passwords. We need to recognize that good security will be less convenient. Again, regulations mandating this will make it more common, and eventually more acceptable.

Information security is complicated, and hard to get right. I’m an expert in the field, and it’s hard for me. It’s hard for the director of the CIA. And it’s hard for you. Security settings on websites are complicated and confusing. Security products are no different. As long as it’s solely the user’s responsibility to get right, and solely the user’s loss if it goes wrong, we’re never going to solve it.

It doesn’t have to be this way. We should demand better and more usable security from the companies we do business with and whose services we use online. But because we don’t have any real visibility into those companies’ security, we should demand our government start regulating the security of these companies as a matter of public safety.

This essay previously appeared on CNN.com.

Posted on October 28, 2015 at 6:24 AM • View Comments

Stealing Fingerprints

The news from the Office of Personnel Management hack keeps getting worse. In addition to the personal records of over 20 million US government employees, we’ve now learned that the hackers stole fingerprint files for 5.6 million of them.

This is fundamentally different from the data thefts we regularly read about in the news, and should give us pause before we entrust our biometric data to large networked databases.

There are three basic kinds of data that can be stolen. The first, and most common, is authentication credentials. These are passwords and other information that allows someone else access into our accounts and—usually—our money. An example would be the 56 million credit card numbers hackers stole from Home Depot in 2014, or the 21.5 million Social Security numbers hackers stole in the OPM breach. The motivation is typically financial. The hackers want to steal money from our bank accounts, process fraudulent credit card charges in our name, or open new lines of credit or apply for tax refunds.

It’s a huge illegal business, but we know how to deal with it when it happens. We detect these hacks as quickly as possible, and update our account credentials as soon as we detect an attack. (We also need to stop treating Social Security numbers as if they were secret.)

The second kind of data stolen is personal information. Examples would be the medical data stolen and exposed when Sony was hacked in 2014, or the very personal data from the infidelity website Ashley Madison stolen and published this year. In these instances, there is no real way to recover after a breach. Once the data is public, or in the hands of an adversary, it’s impossible to make it private again.

This is the main consequence of the OPM data breach. Whoever stole the data—we suspect it was the Chinese—got copies the security-clearance paperwork of all those government employees. This documentation includes the answers to some very personal and embarrassing questions, and now opens these employees up to blackmail and other types of coercion.

Fingerprints are another type of data entirely. They’re used to identify people at crime scenes, but increasingly they’re used as an authentication credential. If you have an iPhone, for example, you probably use your fingerprint to unlock your phone. This type of authentication is increasingly common, replacing a password—something you know—with a biometric: something you are. The problem with biometrics is that they can’t be replaced. So while it’s easy to update your password or get a new credit card number, you can’t get a new finger.

And now, for the rest of their lives, 5.6 million US government employees need to remember that someone, somewhere, has their fingerprints. And we really don’t know the future value of this data. If, in twenty years, we routinely use our fingerprints at ATM machines, that fingerprint database will become very profitable to criminals. If fingerprints start being used on our computers to authorize our access to files and data, that database will become very profitable to spies.

Of course, it’s not that simple. Fingerprint readers employ various technologies to prevent being fooled by fake fingers: detecting temperature, pores, a heartbeat, and so on. But this is an arms race between attackers and defenders, and there are many ways to fool fingerprint readers. When Apple introduced its iPhone fingerprint reader, hackers figured out how to fool it within days, and have continued to fool each new generation of phone readers equally quickly.

Not every use of biometrics requires the biometric data to be stored in a central server somewhere. Apple’s system, for example, only stores the data locally: on your phone. That way there’s no central repository to be hacked. And many systems don’t store the biometric data at all, only a mathematical function of the data that can be used for authentication but can’t be used to reconstruct the actual biometric. Unfortunately, OPM stored copies of actual fingerprints.

Ashley Madison has taught us all the dangers of entrusting our intimate secrets to a company’s computers and networks, because once that data is out there’s no getting it back. All biometric data, whether it be fingerprints, retinal scans, voiceprints, or something else, has that same property. We should be skeptical of any attempts to store this data en masse, whether by governments or by corporations. We need our biometrics for authentication, and we can’t afford to lose them to hackers.

This essay previously appeared on Motherboard.

Posted on October 2, 2015 at 6:35 AM • View Comments

SS7 Phone-Switch Flaw Enabled Surveillance

Interesting:

Remember that vulnerability in the SS7 inter-carrier network that lets hackers and spies track your cellphone virtually anywhere in the world? It’s worse than you might have thought. Researchers speaking to Australia’s 60 Minutes have demonstrated that it’s possible for anyone to intercept phone calls and text messages through that same network. So long as the attackers have access to an SS7 portal, they can forward your conversations to an online recording device and reroute the call to its intended destination. This helps anyone bent on surveillance, of course, but it also means that a well-equipped criminal could grab your verification messages (such as the kind used in two-factor authentication) and use them before you’ve even seen them.

I wrote about cell phone tracking based on SS7 in Data & Goliath (pp. 2-3):

The US company Verint sells cell phone tracking systems to both corporations and governments worldwide. The company’s website says that it’s “a global leader in Actionable Intelligence solutions for customer engagement optimization, security intelligence, and fraud, risk and compliance,” with clients in “more than 10,000 organizations in over 180 countries.” The UK company Cobham sells a system that allows someone to send a “blind” call to a phone—one that doesn’t ring, and isn’t detectable. The blind call forces the phone to transmit on a certain frequency, allowing the sender to track that phone to within one meter. The company boasts government customers in Algeria, Brunei, Ghana, Pakistan, Saudi Arabia, Singapore, and the United States. Defentek, a company mysteriously registered in Panama, sells a system that can “locate and track any phone number in the world…undetected and unknown by the network, carrier, or the target.” It’s not an idle boast; telecommunications researcher Tobias Engel demonstrated the same thing at a hacker conference in 2008. Criminals do the same today.

Posted on August 21, 2015 at 6:47 AM • View Comments

Yet Another New Biometric: Brainprints

New research:

In “Brainprint,” a newly published study in academic journal Neurocomputing, researchers from Binghamton University observed the brain signals of 45 volunteers as they read a list of 75 acronyms, such as FBI and DVD. They recorded the brain’s reaction to each group of letters, focusing on the part of the brain associated with reading and recognizing words, and found that participants’ brains reacted differently to each acronym, enough that a computer system was able to identify each volunteer with 94 percent accuracy. The results suggest that brainwaves could be used by security systems to verify a person’s identity.

I have no idea what the false negatives are, or how robust this biometric is over time, but the article makes the important point that unlike most biometrics this one can be updated.

“If someone’s fingerprint is stolen, that person can’t just grow a new finger to replace the compromised fingerprint—the fingerprint for that person is compromised forever. Fingerprints are ‘non-cancellable.’ Brainprints, on the other hand, are potentially cancellable. So, in the unlikely event that attackers were actually able to steal a brainprint from an authorized user, the authorized user could then ‘reset’ their brainprint,” Laszlo said.

Presumably the resetting involves a new set of acronyms.

Author’s self-archived version of the paper (pdf).

Posted on June 4, 2015 at 10:36 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.