Entries Tagged "keys"

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Microsoft Signing Key Stolen by Chinese

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.”

Posted on August 7, 2023 at 7:03 AMView Comments

Power LED Side-Channel Attack

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.

Posted on June 19, 2023 at 6:52 AMView Comments

Leaked Signing Keys Are Being Used to Sign Malware

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.

Posted on December 8, 2022 at 7:08 AMView Comments

Hacking Automobile Keyless Entry Systems

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?

Posted on October 17, 2022 at 10:07 AMView Comments

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

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Sidebar photo of Bruce Schneier by Joe MacInnis.