Tag Archives: keys

Detect Stripe keys in S3 buckets with Amazon Macie

Post Syndicated from Koulick Ghosh original https://aws.amazon.com/blogs/security/detect-stripe-keys-in-s3-buckets-with-amazon-macie/

Many customers building applications on Amazon Web Services (AWS) use Stripe global payment services to help get their product out faster and grow revenue, especially in the internet economy. It’s critical for customers to securely and properly handle the credentials used to authenticate with Stripe services. Much like your AWS API keys, which enable access to your AWS resources, Stripe API keys grant access to the Stripe account, which allows for the movement of real money. Therefore, you must keep Stripe’s API keys secret and well-controlled. And, much like AWS keys, it’s important to invalidate and re-issue Stripe API keys that have been inadvertently committed to GitHub, emitted in logs, or uploaded to Amazon Simple Storage Service (Amazon S3).

Customers have asked us for ways to reduce the risk of unintentionally exposing Stripe API keys, especially when code files and repositories are stored in Amazon S3. To help meet this need, we collaborated with Stripe to develop a new managed data identifier that you can use to help discover and protect Stripe API keys.

“I’m really glad we could collaborate with AWS to introduce a new managed data identifier in Amazon Macie. Mutual customers of AWS and Stripe can now scan S3 buckets to detect exposed Stripe API keys.”
Martin Pool, Staff Engineer in Cloud Security at Stripe

In this post, we will show you how to use the new managed data identifier in Amazon Macie to discover and protect copies of your Stripe API keys.

About Stripe API keys

Stripe provides payment processing software and services for businesses. Using Stripe’s technology, businesses can accept online payments from customers around the globe.

Stripe authenticates API requests by using API keys, which are included in the request. Stripe takes various measures to help customers keep their secret keys safe and secure. Stripe users can generate test-mode keys, which can only access simulated test data, and which doesn’t move real money. Stripe encourages its customers to use only test API keys for testing and development purposes to reduce the risk of inadvertent disclosure of live keys or of accidentally generating real charges.

Stripe also supports publishable keys, which you can make publicly accessible in your web or mobile app’s client-side code to collect payment information.

In this blog post, we focus on live-mode keys, which are the primary security concern because they can access your real data and cause money movement. These keys should be closely held within the production services that need to use them. Stripe allows keys to be restricted to read or write specific API resources, or used only from certain IP ranges, but even with these restrictions, you should still handle live mode keys with caution.

Stripe keys have distinctive prefixes to help you detect them such as sk_live_ for secret keys, and rk_live_ for restricted keys (which are also secret).

Amazon Macie

Amazon Macie is a fully managed service that uses machine learning (ML) and pattern matching to discover and help protect your sensitive data, such as personally identifiable information. Macie can also provide detailed visibility into your data and help you align with compliance requirements by identifying data that needs to be protected under various regulations, such as the General Data Protection Regulation (GDPR) and the Health Insurance Portability and Accountability Act (HIPAA).

Macie supports a suite of managed data identifiers to make it simpler for you to configure and adopt. Managed data identifiers are prebuilt, customizable patterns that help automatically identify sensitive data, such as credit card numbers, social security numbers, and email addresses.

Now, Macie has a new managed data identifier STRIPE_CREDENTIALS that you can use to identify Stripe API secret keys.

Configure Amazon Macie to detect Stripe credentials

In this section, we show you how to use the managed data identifier STRIPE_CREDENTIALS to detect Stripe API secret keys. We recommend that you carry out these tutorial steps in an AWS account dedicated to experimentation and exploration before you move forward with detection in a production environment.


To follow along with this walkthrough, complete the following prerequisites.

Create example data

The first step is to create some example objects in an S3 bucket in the AWS account. The objects contain strings that resemble Stripe secret keys. You will use the example data later to demonstrate how Macie can detect Stripe secret keys.

To create the example data

  1. Open the S3 console and create an S3 bucket.
  2. Create four files locally, paste the following mock sensitive data into those files, and upload them to the bucket.
     stripe publishable key sk_live_cpegcLxKILlrXYNIuqYhGXoy
     stripe payment sk_live_ijklcLxKILlrXYNIuqYhGXoy
     stripe api key sk_live_abcdcLxKILlrXYNIuqYhGXoy
     stripe secret key sk_live_cpegcLxKILlrXYNIuqYhGXoy

Note: The keys mentioned in the preceding files are mock data and aren’t related to actual live Stripe keys.

Create a Macie job with the STRIPE_CREDENTIALS managed data identifier

Using Macie, you can scan your S3 buckets for sensitive data and security risks. In this step, you run a one-time Macie job to scan an S3 bucket and review the findings.

To create a Macie job with STRIPE_CREDENTIALS

  1. Open the Amazon Macie console, and in the left navigation pane, choose Jobs. On the top right, choose Create job.
    Figure 1: Create Macie Job

    Figure 1: Create Macie Job

  2. Select the bucket that you want Macie to scan or specify bucket criteria, and then choose Next.
    Figure 2: Select S3 bucket

    Figure 2: Select S3 bucket

  3. Review the details of the S3 bucket, such as estimated cost, and then choose Next.
    Figure 3: Review S3 bucket

    Figure 3: Review S3 bucket

  4. On the Refine the scope page, choose One-time job, and then choose Next.

    Note: After you successfully test, you can schedule the job to scan S3 buckets at the frequency that you choose.

    Figure 4: Select one-time job

    Figure 4: Select one-time job

  5. For Managed data identifier options, select Custom and then select Use specific managed data identifiers. For Select managed data identifiers, search for STRIPE_CREDENTIALS and then select it. Choose Next.
    Figure 5: Select managed data identifier

    Figure 5: Select managed data identifier

  6. Enter a name and an optional description for the job, and then choose Next.
    Figure 6: Enter job name

    Figure 6: Enter job name

  7. Review the job details and choose Submit. Macie will create and start the job immediately, and the job will run one time.
  8. When the Status of the job shows Complete, select the job, and from the Show results dropdown, select Show findings.
    Figure 7: Select the job and then select Show findings

    Figure 7: Select the job and then select Show findings

  9. You can now review the findings for sensitive data in your S3 bucket. As shown in Figure 8, Macie detected Stripe keys in each of the four files, and categorized the findings as High severity. You can review and manage the findings in the Macie console, retrieve them through the Macie API for further analysis, send them to Amazon EventBridge for automated processing, or publish them to AWS Security Hub for a comprehensive view of your security state.
    Figure 8: Review the findings

    Figure 8: Review the findings

Respond to unintended disclosure of Stripe API keys

If you discover Stripe live-mode keys (or other sensitive data) in an S3 bucket, then through the Stripe dashboard, you can roll your API keys to revoke access to the compromised key and generate a new one. This helps ensure that the key can’t be used to make malicious API requests. Make sure that you install the replacement key into the production services that need it. In the longer term, you can take steps to understand the path by which the key was disclosed and help prevent a recurrence.


In this post, you learned about the importance of safeguarding Stripe API keys on AWS. By using Amazon Macie with managed data identifiers, setting up regular reviews and restricted access to S3 buckets, training developers in security best practices, and monitoring logs and repositories, you can help mitigate the risk of key exposure and potential security breaches. By adhering to these practices, you can help ensure a robust security posture for your sensitive data on AWS.

If you have feedback about this post, submit comments in the Comments section below. If you have questions about this post, start a new thread on Amazon Macie re:Post.

Koulick Ghosh

Koulick Ghosh

Koulick is a Senior Product Manager in AWS Security based in Seattle, WA. He loves speaking with customers about how AWS Security services can help improve their security. In his free time, he enjoys playing the guitar, reading, and exploring the Pacific Northwest.

Sagar Gandha

Sagar Gandha

Sagar is an experienced Senior Technical Account Manager at AWS adept at assisting large customers in enterprise support. He offers expert guidance on best practices, facilitates access to subject matter experts, and delivers actionable insights on optimizing AWS spend, workloads, and events. Outside of work, Sagar loves spending time with his kids.

Mohan Musti

Mohan Musti

Mohan is a Senior Technical Account Manager at AWS based in Dallas. Mohan helps customers architect and optimize applications on AWS. In his spare time, he enjoys spending time with his family and camping.

Cryptocurrency Startup Loses Encryption Key for Electronic Wallet

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/09/cryptocurrency-startup-loses-encryption-key-for-electronic-wallet.html

The cryptocurrency fintech startup Prime Trust lost the encryption key to its hardware wallet—and the recovery key—and therefore $38.9 million. It is now in bankruptcy.

I can’t understand why anyone thinks these technologies are a good idea.

Cryptographic Flaw in Libbitcoin Explorer Cryptocurrency Wallet

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/08/cryptographic-flaw-in-libbitcoin-explorer-cryptocurrency-wallet.html

Cryptographic flaws still matter. Here’s a flaw in the random-number generator used to create private keys. The seed has only 32 bits of entropy.

Seems like this flaw is being exploited in the wild.

EDITED TO ADD (8/14): A good explainer.

Microsoft Signing Key Stolen by Chinese

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/08/microsoft-signing-key-stolen-by-chinese.html

A bunch of networks, including US Government networks, have been hacked by the Chinese. The hackers used forged authentication tokens to access user email, using a stolen Microsoft Azure account consumer signing key. Congress wants answers. The phrase “negligent security practices” is being tossed about—and with good reason. Master signing keys are not supposed to be left around, waiting to be stolen.

Actually, two things went badly wrong here. The first is that Azure accepted an expired signing key, implying a vulnerability in whatever is supposed to check key validity. The second is that this key was supposed to remain in the the system’s Hardware Security Module—and not be in software. This implies a really serious breach of good security practice. The fact that Microsoft has not been forthcoming about the details of what happened tell me that the details are really bad.

I believe this all traces back to SolarWinds. In addition to Russia inserting malware into a SolarWinds update, China used a different SolarWinds vulnerability to break into networks. We know that Russia accessed Microsoft source code in that attack. I have heard from informed government officials that China used their SolarWinds vulnerability to break into Microsoft and access source code, including Azure’s.

I think we are grossly underestimating the long-term results of the SolarWinds attacks. That backdoored update was downloaded by over 14,000 networks worldwide. Organizations patched their networks, but not before Russia—and others—used the vulnerability to enter those networks. And once someone is in a network, it’s really hard to be sure that you’ve kicked them out.

Sophisticated threat actors are realizing that stealing source code of infrastructure providers, and then combing that code for vulnerabilities, is an excellent way to break into organizations who use those infrastructure providers. Attackers like Russia and China—and presumably the US as well—are prioritizing going after those providers.

News articles.

EDITED TO ADD: Commentary:

This is from Microsoft’s explanation. The China attackers “acquired an inactive MSA consumer signing key and used it to forge authentication tokens for Azure AD enterprise and MSA consumer to access OWA and Outlook.com. All MSA keys active prior to the incident—including the actor-acquired MSA signing key—have been invalidated. Azure AD keys were not impacted. Though the key was intended only for MSA accounts, a validation issue allowed this key to be trusted for signing Azure AD tokens. The actor was able to obtain new access tokens by presenting one previously issued from this API due to a design flaw. This flaw in the GetAccessTokenForResourceAPI has since been fixed to only accept tokens issued from Azure AD or MSA respectively. The actor used these tokens to retrieve mail messages from the OWA API.”

Power LED Side-Channel Attack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2023/06/power-led-side-channel-attack.html

This is a clever new side-channel attack:

The first attack uses an Internet-connected surveillance camera to take a high-speed video of the power LED on a smart card reader­—or of an attached peripheral device—­during cryptographic operations. This technique allowed the researchers to pull a 256-bit ECDSA key off the same government-approved smart card used in Minerva. The other allowed the researchers to recover the private SIKE key of a Samsung Galaxy S8 phone by training the camera of an iPhone 13 on the power LED of a USB speaker connected to the handset, in a similar way to how Hertzbleed pulled SIKE keys off Intel and AMD CPUs.

There are lots of limitations:

When the camera is 60 feet away, the room lights must be turned off, but they can be turned on if the surveillance camera is at a distance of about 6 feet. (An attacker can also use an iPhone to record the smart card reader power LED.) The video must be captured for 65 minutes, during which the reader must constantly perform the operation.


The attack assumes there is an existing side channel that leaks power consumption, timing, or other physical manifestations of the device as it performs a cryptographic operation.

So don’t expect this attack to be recovering keys in the real world anytime soon. But, still, really nice work.

More details from the researchers.

Leaked Signing Keys Are Being Used to Sign Malware

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/12/leaked-signing-keys-are-being-used-to-sign-malware.html

A bunch of Android OEM signing keys have been leaked or stolen, and they are actively being used to sign malware.

Łukasz Siewierski, a member of Google’s Android Security Team, has a post on the Android Partner Vulnerability Initiative (AVPI) issue tracker detailing leaked platform certificate keys that are actively being used to sign malware. The post is just a list of the keys, but running each one through APKMirror or Google’s VirusTotal site will put names to some of the compromised keys: Samsung, LG, and Mediatek are the heavy hitters on the list of leaked keys, along with some smaller OEMs like Revoview and Szroco, which makes Walmart’s Onn tablets.

This is a huge problem. The whole system of authentication rests on the assumption that signing keys are kept secret by the legitimate signers. Once that assumption is broken, all bets are off:

Samsung’s compromised key is used for everything: Samsung Pay, Bixby, Samsung Account, the phone app, and a million other things you can find on the 101 pages of results for that key. It would be possible to craft a malicious update for any one of these apps, and Android would be happy to install it overtop of the real app. Some of the updates are from today, indicating Samsung has still not changed the key.

Hacking Automobile Keyless Entry Systems

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/10/hacking-automobile-keyless-entry-systems.html

Suspected members of a European car-theft ring have been arrested:

The criminals targeted vehicles with keyless entry and start systems, exploiting the technology to get into the car and drive away.

As a result of a coordinated action carried out on 10 October in the three countries involved, 31 suspects were arrested. A total of 22 locations were searched, and over EUR 1 098 500 in criminal assets seized.

The criminals targeted keyless vehicles from two French car manufacturers. A fraudulent tool—marketed as an automotive diagnostic solution, was used to replace the original software of the vehicles, allowing the doors to be opened and the ignition to be started without the actual key fob.

Among those arrested feature the software developers, its resellers and the car thieves who used this tool to steal vehicles.

The article doesn’t say how the hacking tool got installed into cars. Were there crooked auto mechanics, dealers, or something else?

Relay Attack against Teslas

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/09/relay-attack-against-teslas.html

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.

Hyundai Uses Example Keys for Encryption System

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/08/hyundai-uses-example-keys-for-encryption-system.html

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.

A Taxonomy of Access Control

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/08/a-taxonomy-of-access-control.html

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.

Security Vulnerabilities in Honda’s Keyless Entry System

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/07/security-vulnerabilities-in-hondas-keyless-entry-system.html

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.

Hertzbleed: A New Side-Channel Attack

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/06/hertzbleed-a-new-side-channel-attack.html

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.

Hacking Tesla’s Remote Key Cards

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/06/hacking-teslas-remote-key-cards.html

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.”

Breaking RSA through Insufficiently Random Primes

Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2022/03/breaking-rsa-through-insufficiently-random-primes.html

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.


Post Syndicated from Bruce Schneier original https://www.schneier.com/blog/archives/2020/08/dicekeys.html

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.