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Critical Zcash Vulnerability Found and Fixed

If you’re a user—owner?—of this cryptocurrency, this is important:

On May 29, the security researcher Taylor Hornby found a critical vulnerability in Zcash Orchard privacy pool using Claude Opus 4.8. The Zcash team hired Hornby specifically to look for this kind of issue. He found one fast enough to be embarrassing.

The Orchard pool is the newest and most advanced shielded transaction system in the cryptocurrency Zcash. Introduced in 2022, it allows users to send and receive ZEC while keeping transaction details private. It uses zero-knowledge proofs to validate transactions without revealing amounts or participants. The bug: a specific check that was supposed to validate transaction inputs wasn’t actually enforcing the rules it appeared to enforce. An attacker could have exploited the flaw to feed false inputs into that check and generate ZEC from nothing, with the zero-knowledge proof system blessing the fraudulent transaction as valid.

It’s fixed; that’s the good news. The bad news is that there’s no way of knowing if anyone exploited the vulnerability to steal money. And this fragility is the fundamental problem that makes blockchain such a bad idea.

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Anthropic’s Project Glasswing Update

In April, Anthropic initated Project Glasswing. The idea was to let companies use their new model to find and fix vulnerabilities in their own software. It was a fantastic PR move, and so many press outlets have uncritically parroted Anthropic’s claims that it’s now common wisdom that Mythos is better at finding software vulnerabilities than other models. Which is just not true.

In any case, Anthropic has published a Project Glasswing status report. It’s finding a lot of vulnerabilities in software—yay! Some of them are even dangerous. But almost none of them has been patched. It’s weird. There’s something fishy about the data that I don’t understand. That Anthropic refuses to release details—that it just says “trust us”—is a big problem here.

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Hacking Meta’s AI Chatbot

Hackers are convincing Meta’s AI support chatbot to let them take over other peoples’ accounts:

A video posted on X showed the step-by-step process to hack someone’s Instagram account. The hacker allegedly used a VPN to spoof the targets’ presumed location to avoid triggering Instagram’s automated account protections. Then, the hacker opened a chat with Meta AI Support Assistant and asked the bot to add a new email address to the target’s account. The chatbot can be seen sending a verification code to the email address provided by the hacker; the hacker then shares the verification code with the chatbot, which prompts the chatbot to show a button to “Reset Password.” The hacker enters a new password and takes over the victim’s account.

[…]

On Monday, Instagram spokesperson Andy Stone said in a reply to Wong’s post and others that the issue was now fixed. It’s unclear how many Instagram users had their accounts improperly accessed.

It’s not that easy. Probably this particular tactic is now blocked. But there are others, many others, and they cannot be blocked as a class. The real problem is that LLM chatbots are not trustworthy enough for this application.

Another news article.

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The Intersection of Encryption and AI

As part of their 20th Anniversary celebration, Dark Reading asked five cybersecurity industry leaders who wrote blogs or columns for them over the years to select their favorite piece and share their reflections on the topic today. This is my section.

Renowned technologist and author Bruce Schneier contributed a column on June 20, 2010, warning about cryptography’s inability to secure modern networks, a point he says he has been trying to argue since 2000.

“For a while now, I’ve pointed out that cryptography is singularly ill-suited to solve the major network security problems of today: denial-of-service attacks, website defacement, theft of credit card numbers, identity theft, viruses and worms, DNS attacks, network penetration, and so on.

“Recently, I talked to a former NSA employee at a conference. He told me that back in the 1990s, he had a copy of my book Applied Cryptography by his desk, as did many other cryptographers working at Ft. Meade. People were allowed to refer to it, but they were not allowed to cite it.

“The 1990s were an important decade for cryptography. This was before the internet went mass market, when cryptography was just emerging from a niche academic discipline to a mainstream engineering one. There wasn’t much that programmers could read. The NSA used my book for the same reason it became a bestseller: because it collected all the academic cryptography of the time in one place and made it understandable to people who weren’t mathematicians. They feared it for exactly the same reason.

“I’ve been thinking about that conversation as I revisit a 2010 essay I wrote for Dark Reading, ‘The Failure of Cryptography to Secure Modern Networks.’ Cryptography has inherent mathematical properties that greatly favor the defender. Adding a single bit to the length of a key adds only a slight amount of work for the defender but doubles the amount of work the attacker has to do. Doubling the key length doubles the amount of work the defender has to do (if that—I’m being approximate here) but increases the attacker’s workload exponentially. For many years, we have exploited that mathematical imbalance.

“Computer security is much more balanced. There’ll be a new attack, and a new defense, and a new attack, and a new defense. It’s an arms race between attacker and defender. And it’s a very fast arms race. New vulnerabilities are discovered all the time. The balance can tip from defender to attacker overnight, and back again the night after. Computer security defenses are inherently very fragile.

“That isn’t a new idea. I said much the same thing in the preface to my 2000 book, Secrets and Lies:

“‘Cryptography is a branch of mathematics. And like all mathematics, it involves numbers, equations, and logic. Security, real security that you or I might find useful in our lives, involves people: things people know, relationships between people, people and how they relate to machines. Digital security involves computers: complex, unstable, buggy computers.’

“I especially like how I phrased it in 2016: ‘Cryptography is harder than it looks, primarily because it looks like math. Both algorithms and protocols can be precisely defined and analyzed. This isn’t easy, and there’s a lot of insecure crypto out there, but we cryptographers have gotten pretty good at getting this part right. However, math has no agency; it can’t actually secure anything. For cryptography to work, it needs to be written in software, embedded in a larger software system, managed by an operating system, run on hardware, connected to a network, and configured and operated by users. Each of these steps brings with it difficulties and vulnerabilities.’

“It’s a lesson we have all learned over the decades. Cryptography is still necessary for cybersecurity—although I wouldn’t have used that word back then—but is not sufficient. There are particular attack and forms of mass surveillance that cryptography prevents. But as computers have infused throughout our lives, and networks have connected all those computers, those aspects of cybersecurity have become increasingly important, and vulnerable.

“Today, the cybersecurity world is changing yet again, this time due to the capabilities of artificial intelligence. AI isn’t advancing cryptography, but it’s changing cybersecurity. AI has demonstrated a superhuman ability to find vulnerabilities in software and to write exploits. A similar ability to write patches is probably coming. This has profound implications for both attackers and defenders, and it is unclear who will win the particular arms race in a world of what I call instant software.”

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Vulnerability Disclosure in the Age of AI

New article: “Responsible Disclosure in the Age of AI: A Call for Urgent Action,” by Melissa Hathaway.

Abstract: Artificial intelligence is fundamentally reshaping the balance between vulnerability discovery and remediation. Frontier AI models are now capable of autonomously identifying exploitable software vulnerabilities at unprecedented speed and scale. This development exposes decades of accumulated technical debt created by a software industry that prioritized rapid deployment over secure-by-design engineering practices. Drawing on the evolution of software assurance, vulnerability disclosure frameworks, and U.S. cyber policy, this perspective argues that the current moment represents a strategic inflection point for governments, industry, and critical infrastructure operators. The author examines the growing tension between offensive and defensive equities in cyberspace, the emergence of AI-enabled vulnerability discovery capabilities in both the U.S. and China, and the increasing risks posed by unsupported legacy systems and AI-assisted code generation practices. Responsible disclosure can no longer remain a reactive or fragmented process, but must become a coordinated national and international resilience effort involving governments, software vendors, infrastructure operators, and emergency response organizations. The article concludes with an urgent call for accelerated remediation, large-scale patch management coordination, and sustained investment in automated vulnerability repair capabilities before adversaries exploit this rapidly narrowing window of opportunity.

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Chilling Effects

Younger Americans have soured on the second Donald Trump presidency, but they are not protesting it.

Despite an unpopular Iran war and an even more unpopular Trump administration, college campus protests nationwide have gone silent. And at many schools, student activism is virtually nonexistent.

This silence comes in the wake of a relentless Trump administration war on campus speech that has involved lawsuits, arrests, deportations and expulsions.

Reports cite a range of complicated factors for the restraint, from apathy to technology-induced incapacity. But as public policy and law and social science experts, we believe students aren’t protesting for a very simple reason: They are afraid. They are self-censoring and disengaging from campaign activism to avoid punitive measures.

In law and social science, we call this impact a chilling effect—the behavioral tendency for people in face of a threat to self-censor and restrain their activities for self-protection.

It’s increasingly clear to us that these impacts are not incidental or ancillary to Trump administration policy. Rather, the chilling effects are the point. This is the closest thing to a consistent governing strategy in Trump’s second term.

The broader chill of Trump threats

Chilling effects can be subtle, but today they are everywhere. And it’s not just students who are chilled by Trump administration threats.

Professors are censoring themselves in lectures and rewriting syllabuses. Researchers are stripping grant applications of words that might attract federal scrutiny, or abandoning the topics entirely. Media outlets are modifying their news coverage to avoid Trump lawsuits or sanctions.

Law enforcement and regulatory agencies are refusing to investigate Trump-aligned actors inside or outside government, and major national law firms are declining cases challenging Trump administration policies.

Publishers are “stepping back” from LGBTQ+ books and other progressive subjects. Many in targeted immigrant communities are afraid to leave home to go to work or school.

In most cases, these people and institutions are not being specifically targeted or threatened by Trump. But they are afraid, and their fear is doing the administration’s work for it. They stay silent, avoid attention and confrontation, and look the other way. In other cases, they change their speech and behavior to accommodate or conform to the administration’s worldview.

Of course, there are counterexamples, such as the winter protests in Minneapolis in response to brutality by agents with U.S. Immigration and Customs Enforcement, and the recent “No Kings” rallies. But even here, the broader but less visible trend—chilling effects—is evident.

For instance, in recent reporting on the latest No Kings rallies, many media outlets observed that students were noticeably missing, despite the Trump administration’s unpopularity among younger Americans.

A persistent strategy

We believe none of this is by accident.

In a new book, “Chilling Effects: Repression, Conformity, and Power in the Digital Age,” one of us—Jon Penney—explains how law, technology, and state and corporate power are weaponized to chill and repress, and the dangers this poses for the United States and other democratic societies. The other—Bruce Schneier—has extensively studied the security infrastructure enabling this.

What we see isn’t gratuitous government cruelty, chaos or vengeance. Instead, we see a persistent strategy to maximize fear and chilling effects in ways that are corrosive to freedom and democracy.

Research suggests that surveillance, personal threats, uncertainty and abuse of power are key factors in doing so. The federal government has a clear and systematic pattern of employing these very mechanisms across a number of domains far beyond campuses.

They are evident in militarized raids by Immigration and Customs Enforcement and in journalists being arrested and indicted for reporting on protests. They are made clear in the long list of political enemies the Trump administration has investigated or threatened, including the Federal Reserve chairman. And they can also be seen in the weaponization of technology, including ramping up surveillance to target critics and protestors.

Corrosive to freedom and democracy

History offers some guidance on impacts.

During the McCarthy era, overreaching laws, surveillance, and public and private sector reprisals ostensibly targeted alleged communists. But the real aim was often to suppress progressive journalists, trade unions and political opposition.

In the 1960s, these same tactics were reused by Southern states to chill the Civil Rights Movement. Historians have written about how the widespread fear and conformity of these periods reshaped American society in enduring ways, including the destruction of progressive political movements and both delaying and muting the Civil Rights Movement itself.

When such state threats are systematized, they can foment a broader climate of fear, self-censorship and conformity. In that climate, dissenting speech, political opposition, democratic mobilization and other checks on power become increasingly difficult, even dangerous. It is no surprise, for instance, that Trump critics regularly admit to self-censorship, fearing for their safety.

Chilling effects are thus not only repressive—causing self-censorship—but productive. They produce conforming and compliant speech and behavior, which can have longer-term social impacts. They not only undermine protected rights and suppress accountability but can promote social change—even without a popular mandate to do so.

This latter point is often missed. It explains Trump’s assaults on universities and cultural institutions such as the Kennedy Center for the Arts and the Smithsonian. Often dismissed as peculiar Trump obsessions, they are fully consistent with Project 2025—the sweeping policy blueprint for Trump’s second term authored by a coalition of conservative groups and its call to target the “institutions of American civil society” and “wield federal power” to “reverse” decades of progressive cultural advancements.

In the near term, this means an increasingly weakened democratic society, with the government and its patrons enjoying freedom to pursue their objectives. Over the long term, this can mean a changed society as more conformist and compliant speech and culture become more widely accepted and entrenched.

Not inevitable

In our view, this future is not inevitable, just as the McCarthy era “Red Scare” and violent civil rights era repression were not. In both cases, fear and chilling effects were resisted in law and civil society, as they can be today.

But the central mechanisms—surveillance, uncertainty, personal threats and abuse of power—would need to be addressed. For instance, new legislation could ensure justice for lawless government actors and constrain surveillance. Courts can block abuses of federal power, including illegal arrests, detentions and mass citizen databases.

The media, lawyers and civil society can hold the government accountable. And students, teachers, universities and cultural institutions can resist the tendency to self-censor and conform.

The citizen mobilization in Minnesota and the No Kings rallies are examples of that. But to resist chilling effects and their dangers over the long term, this would have to be the norm, not the exception.

This essay was written with Jon Penney, and originally appeared in The Conversation.

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On AI Security

Good report:

Executive Summary: Let’s say you wanted to make sure that your AI is secure. Can you just maximize the security and privacy benchmark and call it a day? Nope, because benchmarks don’t actually work for measuring AI capabilities (even when they are NOT emergent systemic properties like security). So let’s take a step back: how do you measure security in the first place? Good question. Over the last 30 years, security engineering for software evolved from black box penetration testing, through whitebox code analysis and architectural risk analysis to de facto process-driven standards like the Building Security In Maturity Model (BSIMM). Software had a very deep impact on business operations, and it appears that AI is going to have an even deeper impact. Will a software security-like measurement move work for AI? Probably. In the meantime we can make real progress in AI security by cleaning up our WHAT piles and managing risk by identifying and applying good assurance processes. (Spoiler alert: no matter what we do, we still don’t get a security meter for AI, so we need to be extra vigilant about security.)

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Laurie Anderson Is Quoting Me

Not by name, but Laurie Anderson quotes me in one of the tracks of her new album:

My favorite quote is from a cryptologist who said “If you think technology will solve your problems, you don’t understand technology and you don’t understand your problems.”

Also in interviews:

“Of course, it’s ridiculous, outrageous, blah, blah, blah,” Anderson says about the ad. ‘But, I mean, my favorite quote on this is from a cryptologist who said, ‘If you think technology will solve your problems, you don’t understand technology ­ and you don’t understand your problems.’ And I think I’m completely on board with that.”

People are telling me that she has been reciting this quote in performances for years. (I lost track of her since college and her 1981 hit “O Superman.”)

The origins of the quote is from Roger Needham:

If you think cryptography can solve your problem, you don’t understand your problem and you don’t understand cryptography.

I modified the quote in the preface to my 2000 book Secrets and Lies:

A few years ago I heard a quotation, and I am going to modify it here: If you think technology can solve your security problems, then you don’t understand the problems and you don’t understand the technology.

I can’t tell you why me in 2000 didn’t credit Needham by name. I should have.

I have used the quote pretty consistently since then. Somewhere along the line I dropped “security” from the phrase, and now say it more like Anderson quotes me:

If you think technology will solve your problem, you don’t understand your problem and you don’t understand technology.

I sometimes use singular and sometimes use plural. Sometimes I say “the problem” and “the technology.” But I think the quote flows better ending with just the word “technology.”

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Zero-Day Exploit Against Windows BitLocker

It’s nasty, but it requires physical access to the computer:

The exploit, named YellowKey, was published earlier this week by a researcher who goes by the alias Nightmare-Eclipse. It reliably bypasses default Windows 11 deployments of BitLocker, the full-volume encryption protection Microsoft provides to make disk contents off-limits to anyone without the decryption key, which is stored in a secured piece of hardware known as a trusted platform module (TPM). BitLocker is a mandatory protection for many organizations, including those that contract with governments.

Slashdot thread. And here’s Nightmare-Eclipse’s GitHub account.

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Upcoming Speaking Engagements

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

The list is maintained on this page.

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How Dangerous Is Anthropic’s Mythos AI?

Last month, Anthropic made a remarkable announcement about its new model, Claude Mythos Preview: it was so good at finding security vulnerabilities in software that the company would not release it to the general public. Instead, it would only be available to a select group of companies to scan and fix their own software.

The announcement requires context—but it contained an essential truth.

While Anthropic’s model is really good at finding software vulnerabilities, so are other models. The UK’s AI Security Institute found that OpenAI’s GPT-5.5, already generally available, is comparable in capability. The company Aisle reproduced Anthropic’s published results with smaller, cheaper models.

At the same time, Anthropic’s refusal to publicly release its new model makes a virtue out of necessity. Mythos is very expensive to run, and the company doesn’t appear to have the resources for a general release. What better way to juice the company’s valuation than to hint at capabilities but not prove them, and then have others parrot their claims?

Nonetheless, the truth is scary. Modern generative AI systems—not just Anthropic’s, but OpenAI’s and other, open-source models—are getting really good at finding and exploiting vulnerabilities in software. And that has important ramifications for cybersecurity: on both the offense and the defense.

Attackers will use these capabilities to find, and automatically hack, vulnerabilities in systems of all kinds. They will be able to break into critical systems around the world, sometimes to plant ransomware and make money, sometimes to steal data for espionage purposes, and sometimes to control systems in times of hostility. This will make the world a much more dangerous, and more volatile, place.

But at the same time, defenders will use these same capabilities to find, and then patch, many of those same systems. For example, Mozilla used Mythos to find 271 vulnerabilities in Firefox. Those vulnerabilities have been fixed, and will never again be available to attackers. In the future, AIs automatically finding and fixing vulnerabilities in all software will be a normal part of the development process, which will result in much more secure software.

Of course, it’s not that simple. We should expect a deluge of both attackers using newly found vulnerabilities to break into systems, and at the same time much more frequent software updates for every app and device we use. But lots of systems aren’t patchable, and many systems that are don’t get patched, meaning that many vulnerabilities will stick around. And it does seem that finding and exploiting is easier than finding and fixing. All of this points to a more dangerous short-term future. Organizations will need to adapt their security to this new reality.

But it’s the long term that we need to focus on. Mythos isn’t unique, but it’s more capable than many models that have come before. And it’s less capable than models that will come after. AIs are much better at writing software than they were just six months ago. There’s every reason to believe that they will continue to get better, which means that they will get better at writing more secure software. The endgame gives AI-enhanced defenders advantages over AI-enhanced attackers.

Even more interesting are the broader implications. The same searching, pattern-matching and reasoning capabilities that make these models so good at analyzing software almost certainly apply to similar systems. The tax code isn’t computer code, but it’s a series of algorithms with inputs and outputs. It has vulnerabilities; we call them tax loopholes. It has exploits; we call them tax avoidance strategies. And it has black hat hackers: attorneys and accountants.

Just as these models are finding hundreds of vulnerabilities in complex software systems, we should expect them to be equally effective at finding many new and undiscovered tax loopholes. I am confident that the major investment banks are working on this right now, in secret. They’ve fed AI the tax code of the US, or the UK, or maybe every industrialized country, and tasked the system with looking for money-saving strategies. How many tax loopholes will those AIs find? Ten? One hundred? One thousand? The Double Dutch Irish Sandwich is a tax loophole that involves multiple different tax jurisdictions. Can AIs find loopholes even more complex? We have no idea.

Sure, the AIs will come up with a bunch of tricks that won’t work, but that’s where those attorneys and accountants come in—to verify, and then justify, the loopholes. And then to market them to their wealthy clients.

As goes the tax code, so goes any other complex system of rules and strategies. These models could be tasked with finding loopholes in environmental rules, or food and safety rules—anywhere there are complex regulatory systems and powerful people who want to evade those rules.

The results will be much worse than insecure computers. Tax loopholes result in less revenue collected by governments, and regulatory loopholes allow the powerful to skirt the rules, both of which have all sorts of social ramifications. And while software vendors can patch their systems in days, it generally takes years for a country to amend its tax code. And that process is political, with lobbyists pressuring legislators not to patch. Just look at the carried interest loophole, a US tax dodge that has been exploited for decades. Various administrations have tried to close the vulnerability, but legislators just can’t seem to resist lobbyists long enough to patch it.

AI technologies are poised to remake much of society. Just as the industrial revolution gave humans the ability to consume calories outside of their bodies at scale, the AI revolution will give humans the ability to perform cognitive tasks outside of their bodies at scale. Our systems aren’t designed for that; they’re designed for more human paces of cognition. We’re seeing it right now in the deluge of software vulnerabilities that these models are finding and exploiting. And we will soon see it in a deluge of vulnerabilities in all sorts of other systems of rules. Adapting to this new reality will be hard, but we don’t have any choice.

This essay originally appeared in The Guardian.

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OpenAI’s GPT-5.5 is as Good as Mythos at Finding Security Vulnerabilities

The UK’s AI Security Institute evaluated GPT-5.5’s ability to find security vulnerabilities, and found that it is comparable to Claude Mythos. Note that the OpenAI model is generally available.

Here is the Institute’s evaluation of Mythos.

And here is an analysis of a smaller, cheaper model. It requires more scaffolding from the prompter, but it is also just as good.

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Copy.Fail Linux Vulnerability

This is the worst Linux vulnerability in years.

TL;DR

  • copy.fail is a Linux kernel local privilege escalation, not a browser or clipboard attack. Disclosed by Theori on 29 April 2026 with a working PoC.
  • It abuses the kernel crypto API (AF_ALG sockets) plus splice() to write four bytes at a time straight into the page cache of a file the attacker does not own.
  • The exploit works unmodified across Ubuntu, RHEL, Debian, SUSE, Amazon Linux, Fedora and most others. No race condition, no per-distro offsets.
  • The file on disk is never modified. AIDE, Tripwire and checksum-based monitoring see nothing.
  • Kubernetes Pod Security Standards (Restricted) and the default RuntimeDefault seccomp profile do not block the syscall used. A custom seccomp profile is needed.
  • The mainline fix landed on 1 April. Distros are rolling kernels out now. Patch.

“Local privilege escalation” sounds dry, so let me unpack it. It means: an attacker who already has some way to run code on the machine, even as the most boring unprivileged user, can promote themselves to root. From there they can read every file, install backdoors, watch every process, and pivot to other systems.

Why does that matter on shared infrastructure? Because “local” covers a lot of ground in 2026: every container on a shared Kubernetes node, every tenant on a shared hosting box, every CI/CD job that runs untrusted pull-request code, every WSL2 instance on a Windows laptop, every containerised AI agent given shell access. They all share one Linux kernel with their neighbours. A kernel LPE collapses that boundary.

News article.

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