Entries Tagged "keys"

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Relay Attack against Teslas

Nice work:

Radio relay attacks are technically complicated to execute, but conceptually easy to understand: attackers simply extend the range of your existing key using what is essentially a high-tech walkie-talkie. One thief stands near you while you’re in the grocery store, intercepting your key’s transmitted signal with a radio transceiver. Another stands near your car, with another transceiver, taking the signal from their friend and passing it on to the car. Since the car and the key can now talk, through the thieves’ range extenders, the car has no reason to suspect the key isn’t inside—and fires right up.

But Tesla’s credit card keys, like many digital keys stored in cell phones, don’t work via radio. Instead, they rely on a different protocol called Near Field Communication or NFC. Those keys had previously been seen as more secure, since their range is so limited and their handshakes with cars are more complex.

Now, researchers seem to have cracked the code. By reverse-engineering the communications between a Tesla Model Y and its credit card key, they were able to properly execute a range-extending relay attack against the crossover. While this specific use case focuses on Tesla, it’s a proof of concept—NFC handshakes can, and eventually will, be reverse-engineered.

Posted on September 15, 2022 at 10:28 AMView Comments

Hyundai Uses Example Keys for Encryption System

This is a dumb crypto mistake I had not previously encountered:

A developer says it was possible to run their own software on the car infotainment hardware after discovering the vehicle’s manufacturer had secured its system using keys that were not only publicly known but had been lifted from programming examples.

[…]

“Turns out the [AES] encryption key in that script is the first AES 128-bit CBC example key listed in the NIST document SP800-38A [PDF]”.

[…]

Luck held out, in a way. “Greenluigi1” found within the firmware image the RSA public key used by the updater, and searched online for a portion of that key. The search results pointed to a common public key that shows up in online tutorials like “RSA Encryption & Decryption Example with OpenSSL in C.

EDITED TO ADD (8/23): Slashdot post.

Posted on August 22, 2022 at 6:38 AMView Comments

A Taxonomy of Access Control

My personal definition of a brilliant idea is one that is immediately obvious once it’s explained, but no one has thought of it before. I can’t believe that no one has described this taxonomy of access control before Ittay Eyal laid it out in this paper. The paper is about cryptocurrency wallet design, but the ideas are more general. Ittay points out that a key—or an account, or anything similar—can be in one of four states:

safe Only the user has access,
loss No one has access,
leak Both the user and the adversary have access, or
theft Only the adversary has access.

Once you know these states, you can assign probabilities of transitioning from one state to another (someone hacks your account and locks you out, you forgot your own password, etc.) and then build optimal security and reliability to deal with it. It’s a truly elegant way of conceptualizing the problem.

Posted on August 12, 2022 at 6:38 AMView Comments

Security Vulnerabilities in Honda’s Keyless Entry System

Honda vehicles from 2021 to 2022 are vulnerable to this attack:

On Thursday, a security researcher who goes by Kevin2600 published a technical report and videos on a vulnerability that he claims allows anyone armed with a simple hardware device to steal the code to unlock Honda vehicles. Kevin2600, who works for cybersecurity firm Star-V Lab, dubbed the attack RollingPWN.

[…]

In a phone call, Kevin2600 explained that the attack relies on a weakness that allows someone using a software defined radio—such as HackRF—to capture the code that the car owner uses to open the car, and then replay it so that the hacker can open the car as well. In some cases, he said, the attack can be performed from 30 meters (approximately 98 feet) away.

In the videos, Kevin2600 and his colleagues show how the attack works by unlocking different models of Honda cars with a device connected to a laptop.

The Honda models that Kevin2600 and his colleagues tested the attack on use a so-called rolling code mechanism, which means that­—in theory­—every time the car owner uses the keyfob, it sends a different code to open it. This should make it impossible to capture the code and use it again. But the researchers found that there is a flaw that allows them to roll back the codes and reuse old codes to open the car, Kevin2600 said.

Posted on July 12, 2022 at 7:23 AMView Comments

Hertzbleed: A New Side-Channel Attack

Hertzbleed is a new side-channel attack that works against a variety of microprocressors. Deducing cryptographic keys by analyzing power consumption has long been an attack, but it’s not generally viable because measuring power consumption is often hard. This new attack measures power consumption by measuring time, making it easier to exploit.

The team discovered that dynamic voltage and frequency scaling (DVFS)—a power and thermal management feature added to every modern CPU—allows attackers to deduce the changes in power consumption by monitoring the time it takes for a server to respond to specific carefully made queries. The discovery greatly reduces what’s required. With an understanding of how the DVFS feature works, power side-channel attacks become much simpler timing attacks that can be done remotely.

The researchers have dubbed their attack Hertzbleed because it uses the insights into DVFS to expose­or bleed out­data that’s expected to remain private.

[…]

The researchers have already shown how the exploit technique they developed can be used to extract an encryption key from a server running SIKE, a cryptographic algorithm used to establish a secret key between two parties over an otherwise insecure communications channel.

The researchers said they successfully reproduced their attack on Intel CPUs from the 8th to the 11th generation of the Core microarchitecture. They also claimed that the technique would work on Intel Xeon CPUs and verified that AMD Ryzen processors are vulnerable and enabled the same SIKE attack used against Intel chips. The researchers believe chips from other manufacturers may also be affected.

Posted on June 20, 2022 at 6:23 AMView Comments

Hacking Tesla’s Remote Key Cards

Interesting vulnerability in Tesla’s NFC key cards:

Martin Herfurt, a security researcher in Austria, quickly noticed something odd about the new feature: Not only did it allow the car to automatically start within 130 seconds of being unlocked with the NFC card, but it also put the car in a state to accept entirely new keys—with no authentication required and zero indication given by the in-car display.

“The authorization given in the 130-second interval is too general… [it’s] not only for drive,” Herfurt said in an online interview. “This timer has been introduced by Tesla…in order to make the use of the NFC card as a primary means of using the car more convenient. What should happen is that the car can be started and driven without the user having to use the key card a second time. The problem: within the 130-second period, not only the driving of the car is authorized, but also the [enrolling] of a new key.”

Posted on June 14, 2022 at 7:19 AMView Comments

Breaking RSA through Insufficiently Random Primes

Basically, the SafeZone library doesn’t sufficiently randomize the two prime numbers it used to generate RSA keys. They’re too close to each other, which makes them vulnerable to recovery.

There aren’t many weak keys out there, but there are some:

So far, Böck has identified only a handful of keys in the wild that are vulnerable to the factorization attack. Some of the keys are from printers from two manufacturers, Canon and Fujifilm (originally branded as Fuji Xerox). Printer users can use the keys to generate a Certificate Signing Request. The creation date for the all the weak keys was 2020 or later. The weak Canon keys are tracked as CVE-2022-26351.

Böck also found four vulnerable PGP keys, typically used to encrypt email, on SKS PGP key servers. A user ID tied to the keys implied they were created for testing, so he doesn’t believe they’re in active use.

Posted on March 16, 2022 at 11:35 AMView Comments

Determining Key Shape from Sound

It’s not yet very accurate or practical, but under ideal conditions it is possible to figure out the shape of a house key by listening to it being used.

Listen to Your Key: Towards Acoustics-based Physical Key Inference

Abstract: Physical locks are one of the most prevalent mechanisms for securing objects such as doors. While many of these locks are vulnerable to lock-picking, they are still widely used as lock-picking requires specific training with tailored instruments, and easily raises suspicion. In this paper, we propose SpiKey, a novel attack that significantly lowers the bar for an attacker as opposed to the lock-picking attack, by requiring only the use of a smartphone microphone to infer the shape of victim’s key, namely bittings(or cut depths) which form the secret of a key. When a victim inserts his/her key into the lock, the emitted sound is captured by the attacker’s microphone.SpiKey leverages the time difference between audible clicks to ultimately infer the bitting information, i.e., shape of the physical key. As a proof-of-concept, we provide a simulation, based on real-world recordings, and demonstrate a significant reduction in search spacefrom a pool of more than 330 thousand keys to three candidate keys for the most frequent case.

Scientific American podcast:

The strategy is a long way from being viable in the real world. For one thing, the method relies on the key being inserted at a constant speed. And the audio element also poses challenges like background noise.

Boing Boing post.

EDITED TO ADD (4/14): I seem to have blogged this previously.

Posted on March 24, 2021 at 6:10 AMView Comments

DiceKeys

DiceKeys is a physical mechanism for creating and storing a 192-bit key. The idea is that you roll a special set of twenty-five dice, put them into a plastic jig, and then use an app to convert those dice into a key. You can then use that key for a variety of purposes, and regenerate it from the dice if you need to.

This week Stuart Schechter, a computer scientist at the University of California, Berkeley, is launching DiceKeys, a simple kit for physically generating a single super-secure key that can serve as the basis for creating all the most important passwords in your life for years or even decades to come. With little more than a plastic contraption that looks a bit like a Boggle set and an accompanying web app to scan the resulting dice roll, DiceKeys creates a highly random, mathematically unguessable key. You can then use that key to derive master passwords for password managers, as the seed to create a U2F key for two-factor authentication, or even as the secret key for cryptocurrency wallets. Perhaps most importantly, the box of dice is designed to serve as a permanent, offline key to regenerate that master password, crypto key, or U2F token if it gets lost, forgotten, or broken.

[…]

Schechter is also building a separate app that will integrate with DiceKeys to allow users to write a DiceKeys-generated key to their U2F two-factor authentication token. Currently the app works only with the open-source SoloKey U2F token, but Schechter hopes to expand it to be compatible with more commonly used U2F tokens before DiceKeys ship out. The same API that allows that integration with his U2F token app will also allow cryptocurrency wallet developers to integrate their wallets with DiceKeys, so that with a compatible wallet app, DiceKeys can generate the cryptographic key that protects your crypto coins too.

Here’s the DiceKeys website and app. Here’s a short video demo. Here’s a longer SOUPS talk.

Preorder a set here.

Note: I am an adviser on the project.

Another news article. Slashdot thread. Hacker News thread. Reddit thread.

Posted on August 24, 2020 at 6:23 AMView Comments

Copying a Key by Listening to It in Action

Researchers are using recordings of keys being used in locks to create copies.

Once they have a key-insertion audio file, SpiKey’s inference software gets to work filtering the signal to reveal the strong, metallic clicks as key ridges hit the lock’s pins [and you can hear those filtered clicks online here]. These clicks are vital to the inference analysis: the time between them allows the SpiKey software to compute the key’s inter-ridge distances and what locksmiths call the “bitting depth” of those ridges: basically, how deeply they cut into the key shaft, or where they plateau out. If a key is inserted at a nonconstant speed, the analysis can be ruined, but the software can compensate for small speed variations.

The result of all this is that SpiKey software outputs the three most likely key designs that will fit the lock used in the audio file, reducing the potential search space from 330,000 keys to just three. “Given that the profile of the key is publicly available for commonly used [pin-tumbler lock] keys, we can 3D-print the keys for the inferred bitting codes, one of which will unlock the door,” says Ramesh.

Posted on August 20, 2020 at 6:22 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.