Blog: July 2024 Archives

Providing Security Updates to Automobile Software

Auto manufacturers are just starting to realize the problems of supporting the software in older models:

Today’s phones are able to receive updates six to eight years after their purchase date. Samsung and Google provide Android OS updates and security updates for seven years. Apple halts servicing products seven years after they stop selling them.

That might not cut it in the auto world, where the average age of cars on US roads is only going up. A recent report found that cars and trucks just reached a new record average age of 12.6 years, up two months from 2023. That means the car software hitting the road today needs to work­—and maybe even improve—­beyond 2036. The average length of smartphone ownership is just 2.8 years.

I wrote about this in 2018, in Click Here to Kill Everything, talking about patching as a security mechanism:

This won’t work with more durable goods. We might buy a new DVR every 5 or 10 years, and a refrigerator every 25 years. We drive a car we buy today for a decade, sell it to someone else who drives it for another decade, and that person sells it to someone who ships it to a Third World country, where it’s resold yet again and driven for yet another decade or two. Go try to boot up a 1978 Commodore PET computer, or try to run that year’s VisiCalc, and see what happens; we simply don’t know how to maintain 40-year-old [consumer] software.

Consider a car company. It might sell a dozen different types of cars with a dozen different software builds each year. Even assuming that the software gets updated only every two years and the company supports the cars for only two decades, the company needs to maintain the capability to update 20 to 30 different software versions. (For a company like Bosch that supplies automotive parts for many different manufacturers, the number would be more like 200.) The expense and warehouse size for the test vehicles and associated equipment would be enormous. Alternatively, imagine if car companies announced that they would no longer support vehicles older than five, or ten, years. There would be serious environmental consequences.

We really don’t have a good solution here. Agile updates is how we maintain security in a world where new vulnerabilities arise all the time, and we don’t have the economic incentive to secure things properly from the start.

Posted on July 30, 2024 at 7:07 AM33 Comments

New Research in Detecting AI-Generated Videos

The latest in what will be a continuing arms race between creating and detecting videos:

The new tool the research project is unleashing on deepfakes, called “MISLnet”, evolved from years of data derived from detecting fake images and video with tools that spot changes made to digital video or images. These may include the addition or movement of pixels between frames, manipulation of the speed of the clip, or the removal of frames.

Such tools work because a digital camera’s algorithmic processing creates relationships between pixel color values. Those relationships between values are very different in user-generated or images edited with apps like Photoshop.

But because AI-generated videos aren’t produced by a camera capturing a real scene or image, they don’t contain those telltale disparities between pixel values.

The Drexel team’s tools, including MISLnet, learn using a method called a constrained neural network, which can differentiate between normal and unusual values at the sub-pixel level of images or video clips, rather than searching for the common indicators of image manipulation like those mentioned above.

Research paper.

Posted on July 29, 2024 at 7:02 AM10 Comments

Compromising the Secure Boot Process

This isn’t good:

On Thursday, researchers from security firm Binarly revealed that Secure Boot is completely compromised on more than 200 device models sold by Acer, Dell, Gigabyte, Intel, and Supermicro. The cause: a cryptographic key underpinning Secure Boot on those models that was compromised in 2022. In a public GitHub repository committed in December of that year, someone working for multiple US-based device manufacturers published what’s known as a platform key, the cryptographic key that forms the root-of-trust anchor between the hardware device and the firmware that runs on it. The repository was located at https://github.com/raywu-aaeon/Ryzen2000_4000.git, and it’s not clear when it was taken down.

The repository included the private portion of the platform key in encrypted form. The encrypted file, however, was protected by a four-character password, a decision that made it trivial for Binarly, and anyone else with even a passing curiosity, to crack the passcode and retrieve the corresponding plain text. The disclosure of the key went largely unnoticed until January 2023, when Binarly researchers found it while investigating a supply-chain incident. Now that the leak has come to light, security experts say it effectively torpedoes the security assurances offered by Secure Boot.

[…]

These keys were created by AMI, one of the three main providers of software developer kits that device makers use to customize their UEFI firmware so it will run on their specific hardware configurations. As the strings suggest, the keys were never intended to be used in production systems. Instead, AMI provided them to customers or prospective customers for testing. For reasons that aren’t clear, the test keys made their way into devices from a nearly inexhaustive roster of makers. In addition to the five makers mentioned earlier, they include Aopen, Foremelife, Fujitsu, HP, Lenovo, and Supermicro.

Posted on July 26, 2024 at 12:21 PM49 Comments

The CrowdStrike Outage and Market-Driven Brittleness

Friday’s massive internet outage, caused by a mid-sized tech company called CrowdStrike, disrupted major airlines, hospitals, and banks. Nearly 7,000 flights were canceled. It took down 911 systems and factories, courthouses, and television stations. Tallying the total cost will take time. The outage affected more than 8.5 million Windows computers, and the cost will surely be in the billions of dollars­—easily matching the most costly previous cyberattacks, such as NotPetya.

The catastrophe is yet another reminder of how brittle global internet infrastructure is. It’s complex, deeply interconnected, and filled with single points of failure. As we experienced last week, a single problem in a small piece of software can take large swaths of the internet and global economy offline.

The brittleness of modern society isn’t confined to tech. We can see it in many parts of our infrastructure, from food to electricity, from finance to transportation. This is often a result of globalization and consolidation, but not always. In information technology, brittleness also results from the fact that hundreds of companies, none of which you’ve heard of, each perform a small but essential role in keeping the internet running. CrowdStrike is one of those companies.

This brittleness is a result of market incentives. In enterprise computing—as opposed to personal computing—a company that provides computing infrastructure to enterprise networks is incentivized to be as integral as possible, to have as deep access into their customers’ networks as possible, and to run as leanly as possible.

Redundancies are unprofitable. Being slow and careful is unprofitable. Being less embedded in and less essential and having less access to the customers’ networks and machines is unprofitable—at least in the short term, by which these companies are measured. This is true for companies like CrowdStrike. It’s also true for CrowdStrike’s customers, who also didn’t have resilience, redundancy, or backup systems in place for failures such as this because they are also an expense that affects short-term profitability.

But brittleness is profitable only when everything is working. When a brittle system fails, it fails badly. The cost of failure to a company like CrowdStrike is a fraction of the cost to the global economy. And there will be a next CrowdStrike, and one after that. The market rewards short-term profit-maximizing systems, and doesn’t sufficiently penalize such companies for the impact their mistakes can have. (Stock prices depress only temporarily. Regulatory penalties are minor. Class-action lawsuits settle. Insurance blunts financial losses.) It’s not even clear that the information technology industry could exist in its current form if it had to take into account all the risks such brittleness causes.

The asymmetry of costs is largely due to our complex interdependency on so many systems and technologies, any one of which can cause major failures. Each piece of software depends on dozens of others, typically written by other engineering teams sometimes years earlier on the other side of the planet. Some software systems have not been properly designed to contain the damage caused by a bug or a hack of some key software dependency.

These failures can take many forms. The CrowdStrike failure was the result of a buggy software update. The bug didn’t get caught in testing and was rolled out to CrowdStrike’s customers worldwide. Sometimes, failures are deliberate results of a cyberattack. Other failures are just random, the result of some unforeseen dependency between different pieces of critical software systems.

Imagine a house where the drywall, flooring, fireplace, and light fixtures are all made by companies that need continuous access and whose failures would cause the house to collapse. You’d never set foot in such a structure, yet that’s how software systems are built. It’s not that 100 percent of the system relies on each company all the time, but 100 percent of the system can fail if any one of them fails. But doing better is expensive and doesn’t immediately contribute to a company’s bottom line.

Economist Ronald Coase famously described the nature of the firm­—any business­—as a collection of contracts. Each contract has a cost. Performing the same function in-house also has a cost. When the costs of maintaining the contract are lower than the cost of doing the thing in-house, then it makes sense to outsource: to another firm down the street or, in an era of cheap communication and coordination, to another firm on the other side of the planet. The problem is that both the financial and risk costs of outsourcing can be hidden—delayed in time and masked by complexity—and can lead to a false sense of security when companies are actually entangled by these invisible dependencies. The ability to outsource software services became easy a little over a decade ago, due to ubiquitous global network connectivity, cloud and software-as-a-service business models, and an increase in industry- and government-led certifications and box-checking exercises.

This market force has led to the current global interdependence of systems, far and wide beyond their industry and original scope. It’s why flying planes depends on software that has nothing to do with the avionics. It’s why, in our connected internet-of-things world, we can imagine a similar bad software update resulting in our cars not starting one morning or our refrigerators failing.

This is not something we can dismantle overnight. We have built a society based on complex technology that we’re utterly dependent on, with no reliable way to manage that technology. Compare the internet with ecological systems. Both are complex, but ecological systems have deep complexity rather than just surface complexity. In ecological systems, there are fewer single points of failure: If any one thing fails in a healthy natural ecosystem, there are other things that will take over. That gives them a resilience that our tech systems lack.

We need deep complexity in our technological systems, and that will require changes in the market. Right now, the market incentives in tech are to focus on how things succeed: A company like CrowdStrike provides a key service that checks off required functionality on a compliance checklist, which makes it all about the features that they will deliver when everything is working. That’s exactly backward. We want our technological infrastructure to mimic nature in the way things fail. That will give us deep complexity rather than just surface complexity, and resilience rather than brittleness.

How do we accomplish this? There are examples in the technology world, but they are piecemeal. Netflix is famous for its Chaos Monkey tool, which intentionally causes failures to force the systems (and, really, the engineers) to be more resilient. The incentives don’t line up in the short term: It makes it harder for Netflix engineers to do their jobs and more expensive for them to run their systems. Over years, this kind of testing generates more stable systems. But it requires corporate leadership with foresight and a willingness to spend in the short term for possible long-term benefits.

Last week’s update wouldn’t have been a major failure if CrowdStrike had rolled out this change incrementally: first 1 percent of their users, then 10 percent, then everyone. But that’s much more expensive, because it requires a commitment of engineer time for monitoring, debugging, and iterating. And can take months to do correctly for complex and mission-critical software. An executive today will look at the market incentives and correctly conclude that it’s better for them to take the chance than to “waste” the time and money.

The usual tools of regulation and certification may be inadequate, because failure of complex systems is inherently also complex. We can’t describe the unknown unknowns involved in advance. Rather, what we need to codify are the processes by which failure testing must take place.

We know, for example, how to test whether cars fail well. The National Highway Traffic Safety Administration crashes cars to learn what happens to the people inside. But cars are relatively simple, and keeping people safe is straightforward. Software is different. It is diverse, is constantly changing, and has to continually adapt to novel circumstances. We can’t expect that a regulation that mandates a specific list of software crash tests would suffice. Again, security and resilience are achieved through the process by which we fail and fix, not through any specific checklist. Regulation has to codify that process.

Today’s internet systems are too complex to hope that if we are smart and build each piece correctly the sum total will work right. We have to deliberately break things and keep breaking them. This repeated process of breaking and fixing will make these systems reliable. And then a willingness to embrace inefficiencies will make these systems resilient. But the economic incentives point companies in the other direction, to build their systems as brittle as they can possibly get away with.

This essay was written with Barath Raghavan, and previously appeared on Lawfare.com.

Posted on July 25, 2024 at 2:37 PM28 Comments

Data Wallets Using the Solid Protocol

I am the Chief of Security Architecture at Inrupt, Inc., the company that is commercializing Tim Berners-Lee’s Solid open W3C standard for distributed data ownership. This week, we announced a digital wallet based on the Solid architecture.

Details are here, but basically a digital wallet is a repository for personal data and documents. Right now, there are hundreds of different wallets, but no standard. We think designing a wallet around Solid makes sense for lots of reasons. A wallet is more than a data store—data in wallets is for using and sharing. That requires interoperability, which is what you get from an open standard. It also requires fine-grained permissions and robust security, and that’s what the Solid protocols provide.

I think of Solid as a set of protocols for decoupling applications, data, and security. That’s the sort of thing that will make digital wallets work.

Posted on July 25, 2024 at 7:05 AM13 Comments

Robot Dog Internet Jammer

Supposedly the DHS has these:

The robot, called “NEO,” is a modified version of the “Quadruped Unmanned Ground Vehicle” (Q-UGV) sold to law enforcement by a company called Ghost Robotics. Benjamine Huffman, the director of DHS’s Federal Law Enforcement Training Centers (FLETC), told police at the 2024 Border Security Expo in Texas that DHS is increasingly worried about criminals setting “booby traps” with internet of things and smart home devices, and that NEO allows DHS to remotely disable the home networks of a home or building law enforcement is raiding. The Border Security Expo is open only to law enforcement and defense contractors. A transcript of Huffman’s speech was obtained by the Electronic Frontier Foundation’s Dave Maass using a Freedom of Information Act request and was shared with 404 Media.

“NEO can enter a potentially dangerous environment to provide video and audio feedback to the officers before entry and allow them to communicate with those in that environment,” Huffman said, according to the transcript. “NEO carries an onboard computer and antenna array that will allow officers the ability to create a ‘denial-of-service’ (DoS) event to disable ‘Internet of Things’ devices that could potentially cause harm while entry is made.”

Slashdot thread.

Posted on July 24, 2024 at 11:25 AM12 Comments

Criminal Gang Physically Assaulting People for Their Cryptocurrency

This is pretty horrific:

…a group of men behind a violent crime spree designed to compel victims to hand over access to their cryptocurrency savings. That announcement and the criminal complaint laying out charges against St. Felix focused largely on a single theft of cryptocurrency from an elderly North Carolina couple, whose home St. Felix and one of his accomplices broke into before physically assaulting the two victims—­both in their seventies—­and forcing them to transfer more than $150,000 in Bitcoin and Ether to the thieves’ crypto wallets.

I think cryptocurrencies are more susceptible to this kind of real-world attack because they are largely outside the conventional banking system. Yet another reason to stay away from them.

Posted on July 18, 2024 at 11:33 AM27 Comments

Cloudflare Reports that Almost 7% of All Internet Traffic Is Malicious

6.8%, to be precise.

From ZDNet:

However, Distributed Denial of Service (DDoS) attacks continue to be cybercriminals’ weapon of choice, making up over 37% of all mitigated traffic. The scale of these attacks is staggering. In the first quarter of 2024 alone, Cloudflare blocked 4.5 million unique DDoS attacks. That total is nearly a third of all the DDoS attacks they mitigated the previous year.

But it’s not just about the sheer volume of DDoS attacks. The sophistication of these attacks is increasing, too. Last August, Cloudflare mitigated a massive HTTP/2 Rapid Reset DDoS attack that peaked at 201 million requests per second (RPS). That number is three times bigger than any previously observed attack.

It wasn’t just Cloudflare that was hit by the largest DDoS attack in its history. Google Cloud reported the same attack peaked at an astonishing 398 million RPS. So, how big is that number? According to Google, Google Cloud was slammed by more RPS in two minutes than Wikipedia saw traffic during September 2023.

Posted on July 17, 2024 at 12:03 PM26 Comments

Hacking Scientific Citations

Some scholars are inflating their reference counts by sneaking them into metadata:

Citations of scientific work abide by a standardized referencing system: Each reference explicitly mentions at least the title, authors’ names, publication year, journal or conference name, and page numbers of the cited publication. These details are stored as metadata, not visible in the article’s text directly, but assigned to a digital object identifier, or DOI—a unique identifier for each scientific publication.

References in a scientific publication allow authors to justify methodological choices or present the results of past studies, highlighting the iterative and collaborative nature of science.

However, we found through a chance encounter that some unscrupulous actors have added extra references, invisible in the text but present in the articles’ metadata, when they submitted the articles to scientific databases. The result? Citation counts for certain researchers or journals have skyrocketed, even though these references were not cited by the authors in their articles.

[…]

In the journals published by Technoscience Academy, at least 9% of recorded references were “sneaked references.” These additional references were only in the metadata, distorting citation counts and giving certain authors an unfair advantage. Some legitimate references were also lost, meaning they were not present in the metadata.

In addition, when analyzing the sneaked references, we found that they highly benefited some researchers. For example, a single researcher who was associated with Technoscience Academy benefited from more than 3,000 additional illegitimate citations. Some journals from the same publisher benefited from a couple hundred additional sneaked citations.

Be careful what you’re measuring, because that’s what you’ll get. Make sure it’s what you actually want.

Posted on July 15, 2024 at 1:13 PM9 Comments

Upcoming Speaking Engagements

This is a current list of where and when I am scheduled to speak:

  • I’m speaking—along with John Bruce, the CEO and Co-founder of Inrupt—at the 18th Annual CDOIQ Symposium in Cambridge, Massachusetts, USA. The symposium runs from July 16 through 18, 2024, and my session is on Tuesday, July 16 at 3:15 PM. The symposium will also be livestreamed through the Whova platform.
  • I’m speaking on “Reimagining Democracy in the Age of AI” at the Bozeman Library in Bozeman, Montana, USA, July 18, 2024. The event will also be available via Zoom.
  • I’m speaking at the TEDxBillings Democracy Event in Billings, Montana, USA, on July 19, 2024.

The list is maintained on this page.

Posted on July 14, 2024 at 12:05 PM1 Comments

Friday Squid Blogging: 1994 Lair of Squid Game

I didn’t know:

In 1994, Hewlett-Packard released a miracle machine: the HP 200LX pocket-size PC. In the depths of the device, among the MS-DOS productivity apps built into its fixed memory, there lurked a first-person maze game called Lair of Squid.

[…]

In Lair of Squid, you’re trapped in an underwater labyrinth, seeking a way out while avoiding squid roaming the corridors. A collision with any cephalopod results in death. To progress through each stage and ascend to the surface, you locate the exit and provide a hidden, scrambled code word. The password is initially displayed as asterisks, with letters revealed as you encounter them within the maze.

Blog moderation policy.

Posted on July 12, 2024 at 5:01 PM

The NSA Has a Long-Lost Lecture by Adm. Grace Hopper

The NSA has a video recording of a 1982 lecture by Adm. Grace Hopper titled “Future Possibilities: Data, Hardware, Software, and People.” The agency is (so far) refusing to release it.

Basically, the recording is in an obscure video format. People at the NSA can’t easily watch it, so they can’t redact it. So they won’t do anything.

With digital obsolescence threatening many early technological formats, the dilemma surrounding Admiral Hopper’s lecture underscores the critical need for and challenge of digital preservation. This challenge transcends the confines of NSA’s operational scope. It is our shared obligation to safeguard such pivotal elements of our nation’s history, ensuring they remain within reach of future generations. While the stewardship of these recordings may extend beyond the NSA’s typical purview, they are undeniably a part of America’s national heritage.

Surely we can put pressure on them somehow.

EDITED TO ADD (8/27): It is published.

Posted on July 12, 2024 at 7:04 AM39 Comments

RADIUS Vulnerability

New attack against the RADIUS authentication protocol:

The Blast-RADIUS attack allows a man-in-the-middle attacker between the RADIUS client and server to forge a valid protocol accept message in response to a failed authentication request. This forgery could give the attacker access to network devices and services without the attacker guessing or brute forcing passwords or shared secrets. The attacker does not learn user credentials.

This is one of those vulnerabilities that comes with a cool name, its own website, and a logo.

News article. Research paper.

Posted on July 10, 2024 at 10:42 AM6 Comments

Reverse-Engineering Ticketmaster’s Barcode System

Interesting:

By reverse-engineering how Ticketmaster and AXS actually make their electronic tickets, scalpers have essentially figured out how to regenerate specific, genuine tickets that they have legally purchased from scratch onto infrastructure that they control. In doing so, they are removing the anti-scalping restrictions put on the tickets by Ticketmaster and AXS.

EDITED TO ADD (7/14): More information.

Posted on July 9, 2024 at 12:27 PM7 Comments

New Open SSH Vulnerability

It’s a serious one:

The vulnerability, which is a signal handler race condition in OpenSSH’s server (sshd), allows unauthenticated remote code execution (RCE) as root on glibc-based Linux systems; that presents a significant security risk. This race condition affects sshd in its default configuration.

[…]

This vulnerability, if exploited, could lead to full system compromise where an attacker can execute arbitrary code with the highest privileges, resulting in a complete system takeover, installation of malware, data manipulation, and the creation of backdoors for persistent access. It could facilitate network propagation, allowing attackers to use a compromised system as a foothold to traverse and exploit other vulnerable systems within the organization.

Moreover, gaining root access would enable attackers to bypass critical security mechanisms such as firewalls, intrusion detection systems, and logging mechanisms, further obscuring their activities. This could also result in significant data breaches and leakage, giving attackers access to all data stored on the system, including sensitive or proprietary information that could be stolen or publicly disclosed.

This vulnerability is challenging to exploit due to its remote race condition nature, requiring multiple attempts for a successful attack. This can cause memory corruption and necessitate overcoming Address Space Layout Randomization (ASLR). Advancements in deep learning may significantly increase the exploitation rate, potentially providing attackers with a substantial advantage in leveraging such security flaws.

The details. News articles. CVE data. Slashdot thread.

Posted on July 3, 2024 at 11:27 AM28 Comments

Upcoming Book on AI and Democracy

If you’ve been reading my blog, you’ve noticed that I have written a lot about AI and democracy, mostly with my co-author Nathan Sanders. I am pleased to announce that we’re writing a book on the topic.

This isn’t a book about deep fakes, or misinformation. This is a book about what happens when AI writes laws, adjudicates disputes, audits bureaucratic actions, assists in political strategy, and advises citizens on what candidates and issues to support. It’s a book that tries to look into what an AI-assisted democratic system might look like, and then at how to best ensure that we make use of the good parts while avoiding the bad parts.

This is what I talked about in my RSA Conference speech last month, which you can both watch and read. (You can also read earlier attempts at this idea.)

The book will be published by MIT Press sometime in fall 2025, with an open-access digital version available a year after that. (It really can’t be published earlier. Nothing published this year will rise above the noise of the US presidential election, and anything published next spring will have to go to press without knowing the results of that election.)

Right now, the organization of the book is in six parts:

AI-Assisted Politicians
AI-Assisted Legislators
The AI-Assisted Administration
The AI-Assisted Legal System
AI-Assisted Citizens
Getting the Future We Want

It’s too early to share a more detailed table of contents, but I would like help thinking about titles. Below are my current list of brainstorming ideas: both titles and subtitles. Please mix and match, or suggest your own in the comments. No idea is too far afield, because anything can spark more ideas.

Titles:

AI and Democracy
Democracy with AI
Democracy after AI
Democratia ex Machina
Democracy ex Machina
E Pluribus, Machina
Democracy and the Machines
Democracy with Machines
Building Democracy with Machines
Democracy in the Loop
We the People + AI
Artificial Democracy
AI Enhanced Democracy
The State of AI
Citizen AI

Trusting the Bots
Trusting the Computer
Trusting the Machine

The End of the Beginning
Sharing Power
Better Run
Speed, Scale, Scope, and Sophistication
The New Model of Governance
Model Citizen
Artificial Individualism

Subtitles:

How AI Upsets the Power Balances of Democracy
Twenty (or So) Ways AI will Change Democracy
Reimagining Democracy for the Age of AI
Who Wins and Loses
How Democracy Thrives in an AI-Enhanced World
Ensuring that AI Enhances Democracy and Doesn’t Destroy It
How AI Will Change Politics, Legislating, Bureaucracy, Courtrooms, and Citizens
AI’s Transformation of Government, Citizenship, and Everything In-Between
Remaking Democracy, from Voting to Legislating to Waiting in Line
How to Make Democracy Work for People in an AI Future
How AI Will Totally Reshape Democracies and Democratic Institutions
Who Wins and Loses when AI Governs
How to Win and Not Lose With AI as a Partner
AI’s Transformation of Democracy, for Better and for Worse
How AI Can Improve Society and Not Destroy It
How AI Can Improve Society and Not Subvert It
Of the People, for the People, with a Whole lot of AI
How AI Will Reshape Democracy
How the AI Revolution Will Reshape Democracy

Combinations:

Imagining a Thriving Democracy in the Age of AI: How Technology Enhances Democratic Ideals and Nurtures a Society that Serves its People

Making Model Citizens: How to Put AI to Use to Help Democracy
Modeling Citizenship: Who Wins and Who Loses when AI Transforms Democracy
A Model for Government: Democracy with AI, and How to Make it Work for Us

AI of, By, and for the People: How Artificial Intelligence will reshape Democracy
The (AI) Political Revolution: Speed, Scale, Scope, Sophistication, and our Democracy
Speed, Scale, Scope, Sophistication: The AI Democratic Revolution
The Artificial Political Revolution: X Ways AI will Change Democracy…Forever

EDITED TO ADD (7/10): More options:

The Silicon Realignment: The Future of Political Power in a Digital World
Political Machines
EveryTHING is political

Posted on July 2, 2024 at 2:11 PM133 Comments

Model Extraction from Neural Networks

A new paper, “Polynomial Time Cryptanalytic Extraction of Neural Network Models,” by Adi Shamir and others, uses ideas from differential cryptanalysis to extract the weights inside a neural network using specific queries and their results. This is much more theoretical than practical, but it’s a really interesting result.

Abstract:

Billions of dollars and countless GPU hours are currently spent on training Deep Neural Networks (DNNs) for a variety of tasks. Thus, it is essential to determine the difficulty of extracting all the parameters of such neural networks when given access to their black-box implementations. Many versions of this problem have been studied over the last 30 years, and the best current attack on ReLU-based deep neural networks was presented at Crypto’20 by Carlini, Jagielski, and Mironov. It resembles a differential chosen plaintext attack on a cryptosystem, which has a secret key embedded in its black-box implementation and requires a polynomial number of queries but an exponential amount of time (as a function of the number of neurons). In this paper, we improve this attack by developing several new techniques that enable us to extract with arbitrarily high precision all the real-valued parameters of a ReLU-based DNN using a polynomial number of queries and a polynomial amount of time. We demonstrate its practical efficiency by applying it to a full-sized neural network for classifying the CIFAR10 dataset, which has 3072 inputs, 8 hidden layers with 256 neurons each, and about 1.2 million neuronal parameters. An attack following the approach by Carlini et al. requires an exhaustive search over 2^256 possibilities. Our attack replaces this with our new techniques, which require only 30 minutes on a 256-core computer.

Posted on July 1, 2024 at 7:05 AM4 Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.