Entries Tagged "cracking"

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Brute-Forcing a Fingerprint Reader

It’s neither hard nor expensive:

Unlike password authentication, which requires a direct match between what is inputted and what’s stored in a database, fingerprint authentication determines a match using a reference threshold. As a result, a successful fingerprint brute-force attack requires only that an inputted image provides an acceptable approximation of an image in the fingerprint database. BrutePrint manipulates the false acceptance rate (FAR) to increase the threshold so fewer approximate images are accepted.

BrutePrint acts as an adversary in the middle between the fingerprint sensor and the trusted execution environment and exploits vulnerabilities that allow for unlimited guesses.

In a BrutePrint attack, the adversary removes the back cover of the device and attaches the $15 circuit board that has the fingerprint database loaded in the flash storage. The adversary then must convert the database into a fingerprint dictionary that’s formatted to work with the specific sensor used by the targeted phone. The process uses a neural-style transfer when converting the database into the usable dictionary. This process increases the chances of a match.

With the fingerprint dictionary in place, the adversary device is now in a position to input each entry into the targeted phone. Normally, a protection known as attempt limiting effectively locks a phone after a set number of failed login attempts are reached. BrutePrint can fully bypass this limit in the eight tested Android models, meaning the adversary device can try an infinite number of guesses. (On the two iPhones, the attack can expand the number of guesses to 15, three times higher than the five permitted.)

The bypasses result from exploiting what the researchers said are two zero-day vulnerabilities in the smartphone fingerprint authentication framework of virtually all smartphones. The vulnerabilities—­one known as CAMF (cancel-after-match fail) and the other MAL (match-after-lock)—result from logic bugs in the authentication framework. CAMF exploits invalidate the checksum of transmitted fingerprint data, and MAL exploits infer matching results through side-channel attacks.

Depending on the model, the attack takes between 40 minutes and 14 hours.

Also:

The ability of BrutePrint to successfully hijack fingerprints stored on Android devices but not iPhones is the result of one simple design difference: iOS encrypts the data, and Android does not.

Other news articles. Research paper.

Posted on May 30, 2023 at 7:16 AMView Comments

Passwords Are Terrible (Surprising No One)

This is the result of a security audit:

More than a fifth of the passwords protecting network accounts at the US Department of the Interior—including Password1234, Password1234!, and ChangeItN0w!—were weak enough to be cracked using standard methods, a recently published security audit of the agency found.

[…]

The results weren’t encouraging. In all, the auditors cracked 18,174—or 21 percent—­of the 85,944 cryptographic hashes they tested; 288 of the affected accounts had elevated privileges, and 362 of them belonged to senior government employees. In the first 90 minutes of testing, auditors cracked the hashes for 16 percent of the department’s user accounts.

The audit uncovered another security weakness—the failure to consistently implement multi-factor authentication (MFA). The failure extended to 25—­or 89 percent—­of 28 high-value assets (HVAs), which, when breached, have the potential to severely impact agency operations.

Original story:

To make their point, the watchdog spent less than $15,000 on building a password-cracking rig—a setup of a high-performance computer or several chained together ­- with the computing power designed to take on complex mathematical tasks, like recovering hashed passwords. Within the first 90 minutes, the watchdog was able to recover nearly 14,000 employee passwords, or about 16% of all department accounts, including passwords like ‘Polar_bear65’ and ‘Nationalparks2014!’.

Posted on February 1, 2023 at 7:08 AMView Comments

US Schools Are Buying Cell Phone Unlocking Systems

Gizmodo is reporting that schools in the US are buying equipment to unlock cell phones from companies like Cellebrite:

Gizmodo has reviewed similar accounting documents from eight school districts, seven of which are in Texas, showing that administrators paid as much $11,582 for the controversial surveillance technology. Known as mobile device forensic tools (MDFTs), this type of tech is able to siphon text messages, photos, and application data from student’s devices. Together, the districts encompass hundreds of schools, potentially exposing hundreds of thousands of students to invasive cell phone searches.

The eighth district was in Los Angeles.

Posted on December 18, 2020 at 6:53 AMView Comments

BlackBerry Phone Cracked

Australia is reporting that a BlackBerry device has been cracked after five years:

An encrypted BlackBerry device that was cracked five years after it was first seized by police is poised to be the key piece of evidence in one of the state’s longest-running drug importation investigations.

In April, new technology “capabilities” allowed authorities to probe the encrypted device….

No details about those capabilities.

Posted on August 3, 2020 at 11:54 AMView Comments

Daphne Caruana Galizia's Murder and the Security of WhatsApp

Daphne Caruana Galizia was a Maltese journalist whose anti-corruption investigations exposed powerful people. She was murdered in October by a car bomb.

Galizia used WhatsApp to communicate securely with her sources. Now that she is dead, the Maltese police want to break into her phone or the app, and find out who those sources were.

One journalist reports:

Part of Daphne’s destroyed smart phone was elevated from the scene.

Investigators say that Caruana Galizia had not taken her laptop with her on that particular trip. If she had done so, the forensic experts would have found evidence on the ground.

Her mobile phone is also being examined, as can be seen from her WhatsApp profile, which has registered activity since the murder. But it is understood that the data is safe.

Sources close to the newsroom said that as part of the investigation her sim card has been cloned. This is done with the help of mobile service providers in similar cases. Asked if her WhatsApp messages or any other messages that were stored in her phone will be retrieved, the source said that since the messaging application is encrypted, the messages cannot be seen. Therefore it is unlikely that any data can be retrieved.

I am less optimistic than that reporter. The FBI is providing “specific assistance.” The article doesn’t explain that, but I would not be surprised if they were helping crack the phone.

It will be interesting to see if WhatsApp’s security survives this. My guess is that it depends on how much of the phone was recovered from the bombed car.

EDITED TO ADD (11/7): The court-appointed IT expert on the case has a criminal record in the UK for theft and forgery.

Posted on November 6, 2017 at 6:12 AMView Comments

Denuvo DRM Cracked within a Day of Release

Denuvo is probably the best digital-rights management system, used to protect computer games. It’s regularly cracked within a day.

If Denuvo can no longer provide even a single full day of protection from cracks, though, that protection is going to look a lot less valuable to publishers. But that doesn’t mean Denuvo will stay effectively useless forever. The company has updated its DRM protection methods with a number of “variants” since its rollout in 2014, and chatter in the cracking community indicates a revamped “version 5” will launch any day now. That might give publishers a little more breathing room where their games can exist uncracked and force the crackers back to the drawing board for another round of the never-ending DRM battle.

BoingBoing post. Slashdot thread.

Related: Vice has a good history of DRM.

Posted on October 20, 2017 at 9:17 AMView Comments

Robot Safecracking

Robots can crack safes faster than humans—and differently:

So Seidle started looking for shortcuts. First he found that, like many safes, his SentrySafe had some tolerance for error. If the combination includes a 12, for instance, 11 or 13 would work, too. That simple convenience measure meant his bot could try every third number instead of every single number, immediately paring down the total test time to just over four days. Seidle also realized that the bot didn’t actually need to return the dial to its original position before trying every combination. By making attempts in a certain careful order, it could keep two of the three rotors in place, while trying new numbers on just the last, vastly cutting the time to try new combinations to a maximum of four seconds per try. That reduced the maximum bruteforcing time to about one day and 16 hours, or under a day on average.

But Seidle found one more clever trick, this time taking advantage of a design quirk in the safe intended to prevent traditional safecracking. Because the safe has a rod that slips into slots in the three rotors when they’re aligned to the combination’s numbers, a human safecracker can apply light pressure to the safe’s handle, turn its dial, and listen or feel for the moment when that rod slips into those slots. To block that technique, the third rotor of Seidle’s SentrySafe is indented with twelve notches that catch the rod if someone turns the dial while pulling the handle.

Seidle took apart the safe he and his wife had owned for years, and measured those twelve notches. To his surprise, he discovered the one that contained the slot for the correct combination was about a hundredth of an inch narrower than the other eleven. That’s not a difference any human can feel or listen for, but his robot can easily detect it with a few automated measurements that take seconds. That discovery defeated an entire rotor’s worth of combinations, dividing the possible solutions by a factor of 33, and reducing the total cracking time to the robot’s current hour-and-13 minute max.

We’re going to have to start thinking about robot adversaries as we design our security systems.

Posted on July 31, 2017 at 12:19 PMView Comments

More on Chris Roberts and Avionics Security

Last month, I blogged about security researcher Chris Roberts being detained by the FBI after tweeting about avionics security while on a United flight:

But to me, the fascinating part of this story is that a computer was monitoring the Twitter feed and understood the obscure references, alerted a person who figured out who wrote them, researched what flight he was on, and sent an FBI team to the Syracuse airport within a couple of hours. There’s some serious surveillance going on.

We know a lot more of the back story from the FBI’s warrant application. He had been interviewed by the FBI multiple times previously, and was able to take control of at least some of the planes’ controls during flight.

During two interviews with F.B.I. agents in February and March of this year, Roberts said he hacked the inflight entertainment systems of Boeing and Airbus aircraft, during flights, about 15 to 20 times between 2011 and 2014. In one instance, Roberts told the federal agents he hacked into an airplane’s thrust management computer and momentarily took control of an engine, according to an affidavit attached to the application for a search warrant.

“He stated that he successfully commanded the system he had accessed to issue the ‘CLB’ or climb command. He stated that he thereby caused one of the airplane engines to climb resulting in a lateral or sideways movement of the plane during one of these flights,” said the affidavit, signed by F.B.I. agent Mike Hurley.

Roberts also told the agents he hacked into airplane networks and was able “to monitor traffic from the cockpit system.”

According to the search warrant application, Roberts said he hacked into the systems by accessing the in-flight entertainment system using his laptop and an Ethernet cable.

Wired has more.

This makes the FBI’s behavior much more reasonable. They weren’t scanning the Twitter feed for random keywords; they were watching his account.

We don’t know if the FBI’s statements are true, though. But if Roberts was hacking an airplane while sitting in the passenger seat…wow, is that a stupid thing to do.

From the Christian Science Monitor:

But Roberts’ statements and the FBI’s actions raise as many questions as they answer. For Roberts, the question is why the FBI is suddenly focused on years-old research that has long been part of the public record.

“This has been a known issue for four or five years, where a bunch of us have been stood up and pounding our chest and saying, ‘This has to be fixed,'” Roberts noted. “Is there a credible threat? Is something happening? If so, they’re not going to tell us,” he said.

Roberts isn’t the only one confused by the series of events surrounding his detention in April and the revelations about his interviews with federal agents.

“I would like to see a transcript (of the interviews),” said one former federal computer crimes prosecutor, speaking on condition of anonymity. “If he did what he said he did, why is he not in jail? And if he didn’t do it, why is the FBI saying he did?”

The real issue is that the avionics and the entertainment system are on the same network. That’s an even stupider thing to do. Also last month, I wrote about the risks of hacking airplanes, and said that I wasn’t all that worried about it. Now I’m more worried.

Posted on May 19, 2015 at 8:00 AMView Comments

Easily Cracking a Master Combination Lock

Impressive.

Kamkar told Ars his Master Lock exploit started with a well-known vulnerability that allows Master Lock combinations to be cracked in 100 or fewer tries. He then physically broke open a combination lock and noticed the resistance he observed was caused by two lock parts that touched in a way that revealed important clues about the combination. (He likened the Master Lock design to a side channel in cryptographic devices that can be exploited to obtain the secret key.) Kamkar then made a third observation that was instrumental to his Master Lock exploit: the first and third digit of the combination, when divided by four, always return the same remainder. By combining the insights from all three weaknesses he devised the attack laid out in the video.

Posted on May 5, 2015 at 6:59 AMView Comments

Choosing Secure Passwords

As insecure as passwords generally are, they’re not going away anytime soon. Every year you have more and more passwords to deal with, and every year they get easier and easier to break. You need a strategy.

The best way to explain how to choose a good password is to explain how they’re broken. The general attack model is what’s known as an offline password-guessing attack. In this scenario, the attacker gets a file of encrypted passwords from somewhere people want to authenticate to. His goal is to turn that encrypted file into unencrypted passwords he can use to authenticate himself. He does this by guessing passwords, and then seeing if they’re correct. He can try guesses as fast as his computer will process them—and he can parallelize the attack—and gets immediate confirmation if he guesses correctly. Yes, there are ways to foil this attack, and that’s why we can still have four-digit PINs on ATM cards, but it’s the correct model for breaking passwords.

There are commercial programs that do password cracking, sold primarily to police departments. There are also hacker tools that do the same thing. And they’re really good.

The efficiency of password cracking depends on two largely independent things: power and efficiency.

Power is simply computing power. As computers have become faster, they’re able to test more passwords per second; one program advertises eight million per second. These crackers might run for days, on many machines simultaneously. For a high-profile police case, they might run for months.

Efficiency is the ability to guess passwords cleverly. It doesn’t make sense to run through every eight-letter combination from “aaaaaaaa” to “zzzzzzzz” in order. That’s 200 billion possible passwords, most of them very unlikely. Password crackers try the most common passwords first.

A typical password consists of a root plus an appendage. The root isn’t necessarily a dictionary word, but it’s usually something pronounceable. An appendage is either a suffix (90% of the time) or a prefix (10% of the time). One cracking program I saw started with a dictionary of about 1,000 common passwords, things like “letmein,” “temp,” “123456,” and so on. Then it tested them each with about 100 common suffix appendages: “1,” “4u,” “69,” “abc,” “!,” and so on. It recovered about a quarter of all passwords with just these 100,000 combinations.

Crackers use different dictionaries: English words, names, foreign words, phonetic patterns and so on for roots; two digits, dates, single symbols and so on for appendages. They run the dictionaries with various capitalizations and common substitutions: “$” for “s”, “@” for “a,” “1” for “l” and so on. This guessing strategy quickly breaks about two-thirds of all passwords.

Modern password crackers combine different words from their dictionaries:

What was remarkable about all three cracking sessions were the types of plains that got revealed. They included passcodes such as “k1araj0hns0n,” “Sh1a-labe0uf,” “Apr!l221973,” “Qbesancon321,” “DG091101%,” “@Yourmom69,” “ilovetofunot,” “windermere2313,” “tmdmmj17,” and “BandGeek2014.” Also included in the list: “all of the lights” (yes, spaces are allowed on many sites), “i hate hackers,” “allineedislove,” “ilovemySister31,” “iloveyousomuch,” “Philippians4:13,” “Philippians4:6-7,” and “qeadzcwrsfxv1331.” “gonefishing1125” was another password Steube saw appear on his computer screen. Seconds after it was cracked, he noted, “You won’t ever find it using brute force.”

This is why the oft-cited XKCD scheme for generating passwords—string together individual words like “correcthorsebatterystaple”—is no longer good advice. The password crackers are on to this trick.

The attacker will feed any personal information he has access to about the password creator into the password crackers. A good password cracker will test names and addresses from the address book, meaningful dates, and any other personal information it has. Postal codes are common appendages. If it can, the guesser will index the target hard drive and create a dictionary that includes every printable string, including deleted files. If you ever saved an e-mail with your password, or kept it in an obscure file somewhere, or if your program ever stored it in memory, this process will grab it. And it will speed the process of recovering your password.

Last year, Ars Technica gave three experts a 16,000-entry encrypted password file, and asked them to break as many as possible. The winner got 90% of them, the loser 62%—in a few hours. It’s the same sort of thing we saw in 2012, 2007, and earlier. If there’s any new news, it’s that this kind of thing is getting easier faster than people think.

Pretty much anything that can be remembered can be cracked.

There’s still one scheme that works. Back in 2008, I described the “Schneier scheme”:

So if you want your password to be hard to guess, you should choose something that this process will miss. My advice is to take a sentence and turn it into a password. Something like “This little piggy went to market” might become “tlpWENT2m”. That nine-character password won’t be in anyone’s dictionary. Of course, don’t use this one, because I’ve written about it. Choose your own sentence—something personal.

Here are some examples:

  • WIw7,mstmsritt… = When I was seven, my sister threw my stuffed rabbit in the toilet.
  • Wow…doestcst = Wow, does that couch smell terrible.
  • Ltime@go-inag~faaa! = Long time ago in a galaxy not far away at all.
  • uTVM,TPw55:utvm,tpwstillsecure = Until this very moment, these passwords were still secure.

You get the idea. Combine a personally memorable sentence with some personally memorable tricks to modify that sentence into a password to create a lengthy password. Of course, the site has to accept all of those non-alpha-numeric characters and an arbitrarily long password. Otherwise, it’s much harder.

Even better is to use random unmemorable alphanumeric passwords (with symbols, if the site will allow them), and a password manager like Password Safe to create and store them. Password Safe includes a random password generation function. Tell it how many characters you want—twelve is my default—and it’ll give you passwords like y.)v_|.7)7Bl, B3h4_[%}kgv), and QG6,FN4nFAm_. The program supports cut and paste, so you’re not actually typing those characters very much. I’m recommending Password Safe for Windows because I wrote the first version, know the person currently in charge of the code, and trust its security. There are ports of Password Safe to other OSs, but I had nothing to do with those. There are also other password managers out there, if you want to shop around.

There’s more to passwords than simply choosing a good one:

  1. Never reuse a password you care about. Even if you choose a secure password, the site it’s for could leak it because of its own incompetence. You don’t want someone who gets your password for one application or site to be able to use it for another.
  2. Don’t bother updating your password regularly. Sites that require 90-day—or whatever—password upgrades do more harm than good. Unless you think your password might be compromised, don’t change it.
  3. Beware the “secret question.” You don’t want a backup system for when you forget your password to be easier to break than your password. Really, it’s smart to use a password manager. Or to write your passwords down on a piece of paper and secure that piece of paper.
  4. One more piece of advice: if a site offers two-factor authentication, seriously consider using it. It’s almost certainly a security improvement.

This essay previously appeared on BoingBoing.

Posted on March 3, 2014 at 7:48 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.