For context, the author of the linked post, Sam James, is a Gentoo developer.
Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers. One would hope that the former would notify the latter, but apparently it's the responsibility of whoever finds the vulnerability.
i have no problem with disclosing a vulnerability 30 days after its patched in the thing you reported to. (in fact, for those unaware, this is the same policy that google's project zero uses: "90+30" https://projectzero.google/vulnerability-disclosure-policy.h...)
the real problem is:
>It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers.
the reporter should not be the one responsible for reporting separately to every single downstream of the thing they found a vuln in.
what should be happening, as you allude to, is a communication channel between the kernel security team and distribution maintainers. they are in a much better position to coordinate and communicate with the maintainers than random reporters are.
the minute the patch landed in the kernel, a notification should have gone out from the kernel team to a curated list of distro security folk that communicated the importance of the patch, and that the public disclosure would be in 30 days.
Two things can be true simultaneously: the Linux kernel ecosystem should have done better at communicating this to their downstreams, and publicly sharing the exploit was irresponsible.
It is not the responsibility of the initial reporter to communicate to distributions, but the fact that those responsible failed to do that, doesn't give everybody else a free pass.
they did it in the established industry standard way that probably every single security researcher you can think of follows (for good reason, i would add).
whoever did the marketing on "responsible disclosure" was a genius.
tptacek says it much better than me: ""Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules."
In my world, responsibility is not just checking a box of following industry practice. Responsibility, as Wikipedia puts it on their social responsibility page, is working together with others for the benefit of the community. And yes, sometimes that's a bit larger burden than would ideally be the case. It's an imperfect world, after all -- and let's not forget the disclosure as it happened also placed a larger burden than ideal on people scrambling to patch.
And it's not as if I'm asking for a lot of effort. One mail to the security team of a popular distro "hey, we have found this LPE that we'll release with exploit next week, it's patched upstream already in this commit, but you don't seem to have picked it up" would likely have been enough.
The problem is that vendors and developers have repeatedly shown that if you give them an inch, they take a mile. Look at exactly what happened with BlueHammer this month. The security researcher went full disclosure because Microsoft didn't listen to their reports.
Disclosure is vital. It's essential. Because the truth is, if a security researcher has found it, it's extremely likely that it's already been found by either black hats or by state actors. Ignorance is not actually protection from exploitation.
The security researcher also has a responsibility to the general public that is still actively using vulnerable software in ignorance. They need to be protected from vendor and developer negligence as well as from exploits. And the only way to protect yourself from an exploit that hasn't yet been patched is to know that it is there.
The situation with e.g. BlueHammer is fundamentally different: there, the only party that could act on it (Microsoft) ignored them. In this case, the parties that could act on it weren't notified at all.
I'm also not proposing delaying the disclosure to the general public at all. They already waited 30 days with that, that's fine. Just look a bit further than your checklist of only contacting upstream, and send a mail to the distributions if they haven't picked it up a week or two before.
No, this was already timed disclosure. This is very common and widely accepted. 90+30 is what Google Project Zero uses, for example. The security researcher has met their ethical requirements already. This is entirely on the kernel's security team for failure to communicate downstream. That is their responsibility.
The thing is, malicous actors are already monitoring most major projects and doing either source analysis or binary analysis to figure out if changes were made to patch a vulnerability. So, as soon as you actually patch, you really need to disclose because all you're doing by not disclosing the vulnerability is handing the bad actors a free go. The black hats already know. You need to tell the white hats, too, so they can patch.
If the maintainers were unresponsive, sure -- but it seems slightly hard to buy that a responsible reporter trying to make a big splash and a good impression wouldn't first check "did this make it out to the distros?" before making sysadmin's days real shitty, even if technically they could point fingers at other parties. At which point, if they're paying paying any attention at all to what they reported, they may have realized that a mistake was made.
its an industry standard disclosure process. 90 days after reporting, or 30 days after the patch lands, the vuln is disclosed.
the linux kernel team is in a 10000% better position to communicate to and coordinate their downstreams. it seems completely backwards to me to suggest that the reporter should be responsible for figuring out every possible downstream and opening up separate reports to each of them.
the kernel team should have a process/channel to say "this is important! disclosure is in 30 days" that is received by distro security teams. because this is not the first or last time the kernel will have a local privilege escalation. hoping that every reporter, forever in the future, will take the onus on themselves is a recipe for disapointment.
The problem is that if you make too big of a deal about a particular patch, then someone just reverse engineers the vuln from the fix and your responsible disclosure period doesn't exist anymore.
Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
Yes, it's just incompetence from everyone involved, not malice. The company making the disclosure doesn't actually care, and the kernel processes are ineffective.
No, it's incompetence from everyone involved except the company making the disclosure, which, despite the fact that the existing norms are not in fact binding (like people downthread seem to believe), they followed.
One of the reasons this unavoidable deadline was invented, is that the alternative is that one company (or all of them) can simply decide to ignore the vuln report, and then the vulnerability will stay forever undisclosed and forever out there in the wild. And prisoner's dilemma suggests that most companies would chose "do nothing" in this scenario: they don't have to do anything, and if the vuln stays undisclosed, it probably won't be exploited anyhow. Win-win!
I'm confused. Can you explain how this applies to the current situation, where no vuln reports were submitted to the groups responsible for distributing patches?
As a user and admin I disagree. Makes one appreciate what a masterful bit of lexical-engineering “Responsible” Disclosure is, kinda like “Secure” (from me, not forme) Boot — “Responsible” Disclosure is 100% about reputation-management for the various corporation/foundation middleman entities sitting between me and my computer.
Those groups don't care that my individual computer is vulnerable but about nobody being able to say “RHEL is vulnerable” or “Ubuntu is vulnerable”. The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk than to be surprised by the fix and hope nothing bad happened in that meantime.
Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
So if I found a vulnerability that lets hackers withdraw withdraw all the money in your account without a trail on where the money went, you'd be fine with them disclosing it to the public at the same time as the bank learns about it?
Even when there is no known use case of the attack (other than the security researcher's)?
> The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk
By the time you hear about it, the money could be gone because 1000 hackers heard about it from the researcher before you did.
> than to be surprised by the fix and hope nothing bad happened in that meantime.
Seeing your other (rightfully flagged) reply I want to tell you as a neutral party that yes this is missing the point of the analogy. You're basically saying "I would simply hit the brakes on the trolley". It's not that they're so hubristic they think it's impossible to legitimately disagree with their argument, it's that mentioning insurance is sidestepping their argument entirely. You're not addressing the general idea of getting hacked and suffering the consequences of the hack.
Why do you assume banks would keep on doing the same old thing but paying more because of it? The cost would make them learn not to design systems where something like this hypothetical scenario was possible.
You're missing the point (not sure if you're just being dense on purpose...). If you're bank would just return the money then its not a good analogy. If someone gains root access to your machine, presumably they can do damage that can't be undone. In other words, to continue the bank analogy, they would take all your money and you would have no way of getting it back. Presumably, you would not be ok with this. And even if, for some weird reason, you were ok with that, 99.9% of all other people would not be ok with it.
Respectfully, I don't think they're missing the point. Banking, as an institution, has its flaws, but deposit insurance isn't one of them. These vulnerabilities exist whether or not they follow specific disclosure rituals, and systems should be deployed with defense-in-depth so that one privilege-escalation flaw is a recoverable event. Inventing tortured counterfactual analogies doesn't change the basic thrust of the poster's point: the account is insured, so getting drained by an attacker is not a fatal problem. Of course people should still take steps to prevent that from happening, but that doesn't mean prevention is (or should be) the only cure.
My point specifically is that some damage isn't recoverable if there's a vulnerability that gives someone root access. This makes the bank analogy inadequate in the first place. Im not trying to argue about whether deposit insurance is good or bad. Saying they would get the money back assumes the damage done to ones machine would be recoverable, which may not be the case.
My understanding is that FDIC deposit insurance only protects against bank failure, not fraudulent activity. Getting your account drained by an attacker may or may not be covered by a patchwork of other laws at various levels, and you could very well end up shit out of luck.
The disclosure doesn't appear very "full". Looks like this was slipped into mainline linux among dozens of other mostly-irrelevant "CVEs" with nobody highlighting the fact that it is in fact dirty-cow-on-steroids.
Or is everyone expected to upgrade and reboot every 48 hours for all eternity and just deal with potential regressions all the time?
I think this reflects poorly on the original reporters. If you have a weaponized 700-byte universal local root exploit script ready to go, perhaps you should coordinate with major distros for patches to be available before unleashing it on the world. No matter how "veteran" you are.
I think I must misunderstand. Are you saying that you upgrade and reboot every production system that you administer to apply each commit to the kernel (branch it's using) essentially immediately?
That doesn't make sense to me for a few reasons, but I struggle to find a different reading that applies "upgrade and reboot on a moment's notice" to the "slipped into mainline linux" scenario. Kindly help me to do so.
No: your posture with respect to having to cycle servers is a super complicated subject and you address it both with process and with architecture (for instance: you can be blasé about things like CopyFail if you don't allow multitenant shared-kernel in your design in the first place). But no matter what process and design you have, if you're hosting sensitive workloads, you always have to be in a position where you can metabolize having to cycle your servers.
It's a category error to talk about a disclosure event like this as something that would destabilize someone's fleet operations. The Linux kernel is fallible. So is the x64 architecture. You already have to be ready to lock things down and reboot (or mitigate) at a moment's notice.
Remember: whatever else grumpy sysadmins have to say about this, Xint are the good guys. Contrast them with the bad guys, who have vulnerabilities just as bad as CopyFail, but aren't disclosing them at all --- you only find out about them when it's discovered they're actively be exploited. There's no patch at all. There isn't even a characterization of how they work, so that you could quickly see what to seccomp. That's the actual threat environment serious Linux shops operate in.
I find it curious to call someone dropping a weaponized root exploit before major distros or even LTS kernel git branches have patches ready "good guys". This could have been handled with much more grace.
> Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
No, it's really not.
High severity vulnerabilities are responsibly handled by quietly neutralising them with subtle patches that do not reveal the vulnerability, waiting for those patches to distribute. Then patching or removing the root cause of the vulnerability (at which point opportunists will start to notice), and finally publicly disclosing it when there are already good mitigations in place.
Example: spectre/meltdowm mitigations.
I've been asked to use this approach myself when reaching out to maintainers. Sometimes it's possible to directly fix the vulnerability as a "side effect" by making a legitimate adjacent change.
With immediate disclosure the provider can decide to shut down while it is fixed. Or to notify users and make it their decision. Or to be prepared with a diversified infra and switch over to a non-vulnerable path. e.g, BSDs are not affected by CopyFail
Those groups care about whether millions of computers are vulnerable, likely including your computer. If "immediate public disclosure" was done in all cases every vuln would be exploited and patches would be much lower quality. Shortening the disclosure timeline might be a good idea, 90 days is starting to feel long.
I worked at the industry's first commercial vulnerability lab (Secure Networks) in the mid-90s, and many of my friends at the time founded X-Force. Commercial vulnerability research has always been about marketing: marketing pays for the vulnerability research. That doesn't make it any less prosocial.
hope you are also blacklisting google's project zero, and practically every other major player in the vulnerability reporting space, as all use roughly the same bog standard 90+30 policy.
this was a failure of the kernel security team, and their stance on communicating security issues with their downstreams.
Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all. Be glad a patch was available prior to release.
If they want to be seen as responsible rather than opportunistic, then yeah, they should do a proper coordinated disclosure.
Sure, they have no legal obligation to disclose, but we all also have no legal obligation to buy their services. Blacklisting bad actors like this is the right move to discourage this kind of behavior.
they did a proper coordinated disclosure, following the industry standard 90+30 process. that is why the exploit dropped 30 days after the patch landed.
the kernel team should have communicated with their downstream about the importance of the patch. that is the kernel security team's responsibility -- and they are much better positioned to do that than crossing your fingers and hoping every reporter will contact every distro every single time there is a vulnerability.
there are very good reasons disclosure works this way, backed by a couple of decades of debate about it.
Who cares about how you are seen when you are selling 0day for big bucks? The bad actor makes more money than the 'legitimate' one without breaking any law. Punishing someone who didn't alert distros despite a patch being available encourages the company to simply find flaws and sell them for profit - it pays more to begin with.
If they want to take advantage of disclosure for marketing, they're either going to need to accept the norms around responsible disclosure, or they're going to need to accept how shirking those norms will come off. That's life in society. Sometimes it's annoying and sometimes it doesn't feel rational, but these norms have been negotiated throughout the history of our industry and are the way they are for reasons good and bad.
I just don't see the point in complaining about how shirking the norms of your industry will make you look irresponsible. I don't really care that they could have decided to sell the vulnerability instead. It isn't material.
It is absolutely not true that viable commercial vulnerability labs need to "accept the norms around responsible disclosure". There are no such norms. "Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules. It was fantastically successful at that, and it's worth pushing back on at every opportunity.
Tavis Ormandy dropped Zenbleed right onto Twitter. He's doing fine. You can blacklist him if you want; I imagine he's not going to notice.
Microsoft's policy is: "if you contact us with a vulnerability, you automatically agree to the terms of our responsible disclosure policy", which includes waiting 30 days after patch was created, and says nothing about how long that process takes.
There is actually no way to give them a friendly heads up, and then do your own thing. The only way not to be bound is by not sending them any notification at all...
Those norms do not exist. Those are people asking companies to do stuff to benefit the person complaining for free, and many companies will not do that.
It seems to me you're unaware of them, but there are strong norms around disclosure. They've been discussed for decades. It is the expectation that vendors would be notified in a scenario like this.
No, there are users who want those to be norms. Qualified researchers happily sell substantive vulns to people who pay (Governments/Cellebrite and companies like that) enough to quell any complaint.
Which is again, irrelevant to the question of how disclosure works and what expectations there are around it because that is not disclosure and is not what was being discussed.
Unfortunately this is correct. As a security researcher I set millions in profit on fire for reporting vulns to projects that offer no bounties vs selling to highest bidder. I keep doing it because it is the right thing to do, but I would not blame someone that needs to feed their family making a different choice.
We must get public funds to reward ethical disclosure of big impact vulns like this.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all.
I'm so glad these so called "researchers" aren't totally evil, I'm so grateful they're only half evil, give them a lollipop.
Whatever, the way they disclosed it isn't much different from no disclosure at all - the exploit would have been identified in the wild and fixed soon thereafter.
the way the disclosed it is the industry standard. think of the biggest security research teams you know (e.g. google), and they follow the same process.
non-security people always seem to get up in arms about it, but there is very good reasons why the industry has landed on the process it has, which has been hashed out over a few decades.
I'm pretty sure they have a legal obligation in most jurisdictions not to sell 0days for profit.
And they absolutely have a moral obligation to do things in a way to minimize damage and impact to other people's systems. (I'm not saying "responsible disclosure" is the correct way to do that, but hoarding vulnerabilities and exploits and selling them to the highest bidder certainly isn't.)
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit.
Uh... no? If you mean legally, some people might, depending on jurisdiction. But also, ethically? yes, researchers are ethically obligated to disclose responsibly.
> Just fyi.
...
> Be glad it was disclosed at all. Be glad a patch was available prior to release.
I am glad that a patch was available. Equally I can be glad that the linux community is strong enough to respond quickly, while also being angry that this person behaves unethically.
Likewise, when people in my industry behave poorly, or unethically; I'm now the person ethically obligated to both point it out, and condemn it. Not to become an apologist demanding I should be happy watching bad things happen, when much of the fallout could have been prevented with a bit less incompetence and ignorance.
They should have a legal obligation to engage in coordinated/responsible disclosure, and it should be a crime to sell or disclose a 0day to anyone other than a state-designated security organization or the vendor/provider.
If it won’t be handled through criminal law then it’ll be handled through civil litigation: Anyone who was exploited as a result of this disclosure should sue the discloser for contributing to the damage they’ve suffered.
The notification happen when the fix was shipped. That people would prefer to been spoon fed only serious security issues is understandable, but not realistic.
A large percentage of kernel fixes have the potential to be similarly bad. For some the potential isn't even realized until after the fix has shipped.
Ever stable release GregKH says you must upgrade now, because there is something security relevant in there. This happens at least once a week.
As for shared hosting providers it is my sense that there is always at least one local privilege escalation available to miscreants. Making shared hosting only safe if there is a certain amount of trust.
I remember bugs that were similarly bad from my university days 30+ years ago. Has anything substantially changed?
The Linux kernel is not usable as a security boundary, so anyone who wants to do "shared hosting" and not be hacked needs to use something else, like gVisor or firecracker VMs
The only important system that uses it as a security boundary is Android and there is mitigated by the fact that APKs need user approval, plus strict SELinux and seccomp policy plus the GrapheneOS hardening, and in this case the mitigations succeeded (https://discuss.grapheneos.org/d/35110-grapheneos-is-protect...)
I'm quite sure there are many application hosting providers which rely on container runtime such as runC (default runtime of containerd/Docker), and a shared kernel between users.
In a just world, those companies would be held legally accountable for negligent practices. The Linux kernel upstream has made it clear for decades that security is a dirty word.
Without taking a position on the disclosure mechanics: any hosting provider hacked with this was already playing to lose. It is not OK to run competing untrusted tenant workloads under a single shared kernel. Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity.
Expecting people to do the right thing is a fundamental issue here. Why would you ever expect for all of vulnerabilities to be disclosed privately? There's very little actual incentive to do this.
I'm honestly unaware of what systems could be put in place to prevent this but expecting people to always do the right thing is fantasy level thinking. I mean I bet the disclosers thought they were doing the right thing, hence why it's a bad thing to rely on.
The worst thing would be to exploit or sell it for profit. Instead of that, publicizing the exploit is closer to neutral–good in my books, that did trigger a really quick reaction from the different actors to patch their kernels and systems
Imagine how much quicker the distros would have reacted if they were given a heads up a month ago. But, sure, I guess kudos to this company for not being actively criminal, and merely bumblingly incompetent and overly eager to get their marketing pitch out the door.
Why don't all these distro maintainers add their own back doors, and mine crypto off our machines without our knowledge? Surely, there is some legal fine print they can add that would let them do that. There is very little incentive for them to maintain these systems, given how thankless and underpaid the work is.
The patch was available. Upstream just doesn't communicate vulnerabilities because they have a personal dispute with distros about how to handle patching.
If it's not a crime I see no reason not to work with partner nations to build responsible disclosure into a legal framework everywhere because it pretty obviously should be.
You know companies are allowed to pay people to find vulns, and pay people bug bounties?
Instead of that, you’d rather make the law compel free individuals to limit their speech, or to hand over their work to big companies privately, so big companies can save money?
That doesn’t sound like a nice future, if it’s even enforceable at all.
Basic care would involve making sure the patches had made it into the wild before ending the embargo, and nagging the relevant parties if not.
Edit: As of this writing, most distros including Redhat, Fedora, Debian Stable, do not have patches available in the package repos, though they're being actively worked on.
Not true, if there’s any evidence of the exploit being used in the wild, it’s much more responsible to release immediately.
Considering that the patches have been available for a while, someone surely reversed what they were for and was actually exploiting this in the wild.
In the age of AI, I’d argue that “responsible disclosure” is dead. Arguably even in closed source projects. Just ask Claude to do a diff between the previous version and to see whether anything fixed in there could have had security implications.
We’re not there yet, but very soon the only way to responsibly disclose a vulnerability will be immediately.
But they didn't release immediately -- they waited a month, but forgot to tell the distros, and forgot to check if waiting a month had actually lead to distros picking up the patches and shipping them.
Patches are still in the process of landing in most major distros as of the time of this writing. Most users are not able to get an update through their distro's packaging mechanisms.
It's a local vulnerability at least. How many people do you let log in to your router?
With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited. Even with shared hosting, you generally have root in your VM or container anyway. Unless this enables an escape from that?
Still the risk that people who run "curl | bash" without care could get bitten, but usually its "curl | sudo bash" anyway...
> With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited
Things like HPC clusters are multiuser & don't entirely trust their users. If they did we wouldn't need users/groups/permissions etc in the first place.
Yes. Not even just HPC clusters, shared login servers are pretty common in academia. I manage several in our lab. Sure, we mostly trust the users against malice more or less but not so much against incompetence. A malicious vscode plugin would run rampant in this space.
And then there are users running claude-cli and friends who may just find it convenient to use a local root exploit to remove obstacles.
> Even with shared hosting, you generally have root in your VM or container
Lots of shared hosters don't use VMs or containers. It's some arbitrary number of people logging in to a shared system, each one with a home directory under /home/THE_USER_NAME. i've had several such hosters over the years (thankfully not right now, though).
Greg and Linus do not believe in the entire concept of "vulnerabilities" in the Linux kernel and do not believe in the methods that distros use like cherry picking, therefor they typically are against issuing CVEs, scoring CVEs, describing vulnerabilities at all (if you use the word "vulnerability", your patch will be rejected), etc.
It's fundamentally their position to not work the way that you describe.
Partly they already have enough on their plate. It's up to the reporter to pick how to handle the disclosure, and unless a specific maintainer chooses to handle it, the Linux security team clearly says they won't.
Partly they have a strong belief that all kernel bugs are vulnerabilities and all vulnerabilities are just bugs; sometimes taken to the extreme in both ways (on one hand this case where the vulnerability is almost ignored; on the other hand, I saw cases where a VM panic that could be triggered only by a misbehaving host—which could just choose to stop executing the VM—was given a CVE).
This couldn't be more backwards. This has literally nothing to do with bandwidth. The kernel is a CNA, they are explicitly the ones to do this.
The reason they don't is because Linus and Greg have repeatedly, publicly stated that they don't want to because they don't believe that vulnerabilities conceptually make sense for the linux kernel and they refuse to engage in the process.
Seems a little crazy. Somebody should evaluate blast radius and do appropriate distro notifications in a case like this (I presume the impact was part of the disclosure, so not much extra work).
You know the linux kernel is a free software project right? If you think “somebody should” do a thing but you aren’t prepared to do it yourself then you should maybe ask for a full refund.
I think it’s reasonable to expect folks in the security community who go to the trouble of creating a website detailing security vulnerabilities in specific listed software to pre-notify the security teams of that software. The CopyFail website calls out Ubuntu and Red Hat specifically, but apparently the author of the site did not inform them of the issue?
But even if you think making unethical decisions in personal self interest is something no one should be criticized for, surely the Linux kernel team ought to have some process for notifying the top distributions of an upcoming LPE, just out of practicality.
In what sense do you believe that the reporter did not notify the security team of the relevant software? The vulnerability is in the kernel. Reporter responsibly disclosed using the kernel’s security report mechanism and waited until a patch was ready.
Distros are downstream of kernel, that doesn’t entitle them to expect to be contacted directly by every security reporter. That’s not on them. Distros that are big enough should be plugged into the linux security team for notifications.
Security researchers cannot be held responsible for broken lines of communication within the org charts of projects that they study. They’re providing a valuable public service already, how much more do you want?
It is suggested that they out of an abundance of caution and 5 or 6 emails. If this is entirely to much to expect we can always help them by mandating that they spend 6 figures annually meeting a much more robust set of requirements that will include notifying all possible affected parties down to Hannah Montana Linux devs if any still exist.
Any strategy that assumes that the rest of the world is functional or makes you personally responsible for fixing all of it is equally broken but there is a reasonable middle ground and sending a few more emails lies within it
> we can always help them by mandating that they spend 6 figures
Who’s we? Mandate with what authority?
AWS and GCP are downstream another level. Should the reporter also have worked with them? And their customers? And the customers of their customers?
IMO this whole discussion seems like people are annoyed by the security researchers doing god’s work and wish they didn’t exist or think that they should be fully subservient to the projects and companies they are helping for free. The bugs were there before the researchers revealed them!!
> Who knows how many shared hosting providers were hacked with this.
I'd consider a shared hoster which allows users to run their own (native) code and doesn't use VMs for tenant isolation extremely irresponsible in 2026.
This is probably more common than you think. VMs are expensive, both in resources and cost (if you’re using something commercial). OS-level isolation (shared kernel, cgroups, namespaces) is used pervasively
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
It's a total arsehole'y move to not share with open-source projects (like Debian) but for commercial vendors like Microsoft I don't give a crap.
Now let's not get carried away either: that's a privilege escalation, so it already requires access to a local account. We're not exactly in Jia Tan "I backdoor every SSH out there if your Linux distro is using systemd" territory either.
Argument from uncertainty is not a good way to reason about this.
I could equally ask: "Who knows how many attackers learned about this vulnerability from this disclosure, and used it before the distributions fixed it?"
Yes, you could. Thats the core of my point: there is no Right way to handle vulnerability disclosure. There are many competing factors, most of them have major elements of uncertainty because you can’t know who knows what or how various projects or stakeholders will react.
So maybe folks should take a break from the kind of armchair quarterbacking that this was “incredibly irresponsible”, as was done upthread, or that the researchers should be blacklisted for life, as a parallel commenter stated.
and its your opinion that it doesn't. Shall we continue stating the obvious? We are communicating using glyphs. This language is English. We are on Hacker News. This branch of the conversation is extremely unproductive.
I asked a question and you replied with a statement. Your statement didn’t frame itself as an opinion but as fact.
The hilarious bit is that the idea that they needed to coordinate is clearly broken even in just this example. They did give prior notice to the Linux developers, who issued a patch. And they’re still getting raked over the coals in this comment page by armchair quarterbacks who have decided they needed to coordinate with specific distros. If they’d coordinated with those distros, somebody would have a pet distro that didn’t make the cut and they’d be pissed about that.
There are risks no matter how they do it, and there will be people who are pissed no matter how they do it. Security researchers don’t owe anybody a specific methodology.
you seemed to suggest with your initial statement that any disclosure was acceptable as people would have been using the exploit prior to the disclosure. I don't think that's a strong argument given now the initial people who were using the exploit prior to disclosure are now joined by people who have learned of the exploit as a consequence of the disclosure happening before all the distribtions were ready.
So I feel like the argument reduces into "why is it a problem that now anyone could exploit it, if some people were exploiting it already". Which imho isn't a sensible argument because the issue is clearly the amount of people capable of using the exploit for nefarious purposes, which has increased.
Idk why you felt the need to use quotes to wrap something I didn’t say, and that is a pretty uncharitable attempt at reframing my question. If you wanted a quote, here’s what I’d say:
“Because we can’t know if there was exploitation by existing parties who had discovered the vulnerability on their own, there are upsides to disclosing earlier so that affected users can take mitigating steps and review their systems for indicators of compromise. Additionally, the more projects the researchers pull into the loop for coordinated disclosure, the higher the likelihood that they further leak the vulnerability to more attackers.”
Idk why you felt the need to use quotes to wrap something I didn’t say. Despite the fact I didn't say that, its a much more interesting argument than your original statement implies and it is unfortunate we didn't start there.
However the issue is that we cannot know if the attack space has been broadened or lessened as a consequence of this disclosure, because of how eager it was. If it wasn't eager then we could much more comfortable in suggesting that the attack space has probably been reduced.
Given the exploit had been living in the linux code base undetected for so long in the first place, I think its fair to state that disclosing the exploit prior to the distributions being ready and given the distributions are the principal attack vector of the exploit: that the researcher has made the situation worse and should reflect on their actions.
… I used quotes to wrap something that I was saying. I even called out that it was something I was saying, as a more accurate variant of what you’d claimed I meant.
and I prefaced my quotes with the statement "So I feel like the argument reduces into". I mean, idk what punctuation I'm supposed to use there that doesn't offend you, but I just figured we can all read words and it was clear that I wasn't saying you said that, but rather, as I read the argument it was reducable to that and I took issue with that potential reduction.
The idea about the available exploit space and how the actors within it might, or might not move is a much more interesting avenue of conversation and I thank you for elaborating on your initial comment. <3
I do however feel that its hard to be confident about whether or not the attack space has been increased or reduced as a consequence of the eager disclosure. I feel we could make the case either way.
> Who knows how many shared hosting providers were hacked with this.
None? Because nobody* does hosting using Linux users as a security boundary. It's not the 90s.
* Standard HN disclaimer for people that think that some retro shell box with 10 users disproves "nobody": nobody does not literally mean exactly 0 people in this context.
It does? The disclosure even says the concern for single user systems is very low. If someone has access to your single user system, remote or otherwise, you’ve already lost on the sort of device people would be switching from windows to Linux on.
> The disclosure even says the concern for single user systems is very low.
For single user systems (not rigorously defined, I presume it's the intersection of our two definitions which we might be talking about) the nature of the exploit is local privilege escalation, of which there could be many possible, and many mitigations / countermeasures against. This could have suddenly appeared from the ether of "unknown unknowns" for some people.
Those people farther up the food chain still potentially have service accounts, maybe even user accounts for some purposes, perhaps "trusted" services which deliver them code which they deserialize and run once. (Have a pickle.)
severity * impact * likelihood
Not everyone looking to migrate from Windows 95 plans to run everything as root afterward.
Imagine an ignorant response like this from Apple? One of the most short sighted comments I've seen on HN in some time. And the double down! A true master class in misunderstanding the issue and the entire FOSS ecosystem in two sentences.
> Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
Maybe it is irresponsible how little attention we pay to software security. Maybe, software developers of all kind should spend an entire year not developing any features at all, but fix all the tech debt of 30 years instead.
Yes, that sounds revolutionary, but I do not see an alternative in an age where all you need to find kernel bugs of this scale with AI agents.
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
Yes, this was clearly a marketing stunt to promote Xint code.
I, for one, will never use Xint code and will advise everyone to never use it. To anyone working there: enjoy your 15 minutes, I hope this backfires right in your face.
> Note that for Linux kernel vulnerabilities, unless the reporter chooses
to bring it to the linux-distros ML, there is no heads-up to
distributions.
Why would they imply it is incumbent on the reporter to liaise with distributions? That seems to assume a high level of familiarity with the linux project. Vulnerability reporters shouldn’t be responsible for directly working with every downstream consumer of the linux kernel, what’s the limiting principal there? Should the reporter also be directly talking to all device manufacturers that use Linux on their machines?
IMO reporter did more than enough by responsibly disclosing it to linux and waiting for a patch to land.
Aren’t there people in the linux project itself with authority over and responsibility for security vulnerabilities? One would think they would be the ones notifying downstream distros…
```As such, the kernel security team strongly recommends that as a reporter of a potential security issue you DO NOT contact the “linux-distros” mailing list UNTIL a fix is accepted by the affected code’s maintainers and you have read the distros wiki page above and you fully understand the requirements that contacting “linux-distros” will impose on you and the kernel community. ```
The kernel team has been at odds with the CVE process and the oss-security community about this stuff for many, many years now. It's a big part of why the kernel team established a CNA and started flooding CVE notifications; they don't believe that security problems are different than non-security problems, and refuse to establish norms or policies based on the idea that they are.
It's such a bizarre viewpoint. I wonder when Linus will see sense.
IMO it's pretty obviously not a view that they seriously hold, it's just one of those technical justifications people come up with to avoid admitting something they don't want to admit - in this case that Linux has a poor security track record.
Literally never. Why would he? He's surrounded by sycophants. And we have Greg for whenever Linus isn't involved anymore, and Greg is just as boneheaded.
The reporter took time to check and mention on their website specific distributions Ubuntu/RHEL/SUSE. One would have thought reporting to security teams of at least those would be responsible.
If you can't write it down, why would you expect it to be universal and enforceable? Different cultures exist and have different opinions on what "decency' means, after all.
A security researcher's ethical obligations are to protect users over vendors (barring any contractual agreement in place). From what has been discussed in this thread, they meet that bar.
Sure, they could have gone the extra mile to ensure the distros were in a good place to patch before they published the exploit. That's a kindness you can wish for, but don't disparage them for not going that extra mile. It's a bonus.
It's also possible that it simply didn't occur to them to do so this time. There's certainly lessons to be learned either way. I don't know that the right lessons will emerge from hostility.
> If you can't write it down, why would you expect it to be universal and enforceable?
and this is the problem. It used to be the case that if you were smart enough to find an exploit you were also smart enough to realise what would happen if you irresponsibly disclosed it. I guess these tools have made that pattern no longer apply.
From my point of view, they told the kernel security team which is in charge of fixing this. If it’s important for them to tell other people, then it should’ve been written down and further reiterated when they made their report.
The skills to detect code exploits is not the same as the skills to navigate an informal org chart to the satisfaction of an amorphous audience if end users (i.e. us on HN).
That said… as they are a company that supposedly specializes in this field, and is trying to sell a product, I do believe they should do better. Right now, I don’t have much confidence in their product.
Yes :) The blackhatter would obviously sit on it until they can sell it or use it, the whitehatter collaborate the kernel and distros to patch, and the greyhatter argues on HN whether the latest *fail was responsible enough or not.
The reporter made a website explicitly calling out Ubuntu, RedHat, Amazon, and SUSE but didn’t notify them, and you think that’s reasonable? That they might not have known those distributions are downstream from the kernel team?
What is the heuristic for who should get the heads up? Should they notify amazon but not google simply because they named amazon linux in the report? Seems to me the answer to my first question gets messy fast.
Stop blaming the reporter. Start asking kernel to fix their process. Linux kernel is no longer a toy project, it has full time employees employed by various companies. They should have handled notifying distributions. Not some rando.
Just for what it's worth, I just pushed an eBPF-based workaround for people who are running kernels in which AF_ALG is linked directly into the kernel and not as a module: https://github.com/Dabbleam/CVE-2026-31431-mitigation
I am running this in production right now and it mitigates the attack, with no unexpected side-effects as far as I can see.
`nosuid` and probably `nodev` should IMO be the default filesystem mount options.
`/dev` is already a special devtmpfs and the initrd minimal /dev can just explicitly mount the initrd tmpfs rootfs with `dev` and `suid` if necessary.
Letting SUID binaries just "exist" anywhere is a stupendous security issue. What if you mount some external storage medium, how are you to verify that none of the SUID binaries on that block device are malicious.
Additionally, this exploit appears to only work if the user executing the SUID binary can also read the SUID binary. There's no reason for non-root users to have read on a SUID binary.
NixOS does this correctly. No SUID in the normal package installation directory `/nix/store` and no package leakage outside of that no `nosuid` can safety be used on all other mountpoints. The exception is just a single-purpose `/run/wrappers.$hash` directory that safety contains executable ONLY SUID wrappers.
While I hate suid as much as the next person, it's really not the problem here.
The bug that is being exploited gives you basically arbitrary page cache poisoning. At that point it's already game over. Patching a suid program is maybe the easiest way to get a root shell from that but far from the only.
The proof of concept exploit is just that. It is meant to demonstrate one attack vector only. There are many others. If your goal is to prevent the conceptual exploit only then there are many easier ways to accomplish that, such as blacklisting, that does not make you safer.
With this vulnerability you can manipulate the page cache. You could also manipulate ld.so to hook into arbitraty system calls, or set your uid to 0, or any of another dozen or so ways to elevate your privileges.
Mount points have nothing to do with this, even if is always a good idea to disallow suid in user writable areas and prevent reading suid files, but that's for other reasons. NixOS does nothing to fix this and is just as vulnerable as everyone else.
Without read permissions you cannot execute the binary, that would not make any sense.
To execute the binary it needs to be read from disk and loaded into memory.
In fact if you have read permissions but not executable permissions on a specific binary then you can still execute it by calling the linker directly /bin/ld.so.1 /path/to/binary (the linker will read and load the binary and then jump to the entry point without an exec() call)
Removing world-readability from all setuid-root binaries on the system would be sufficient to kill the PoC script provided for this vulnerability. It would not be sufficient to prevent exploitation though; there are many ways to abuse the ability to write to files you have read access to in order to gain root, for example by using the vulnerability to alter the cached copy of a file in /etc/sudoers.d/, or overwrite /etc/shadow, or /etc/crontab, ... the list goes on.
This workaround only applies to kernels with the impacted code compiled as a module. RHEL, Fedora, and Gentoo (we use a modified Fedora config) all are configured to build this in directly. Without a patch or config change (as Sam from Gentoo was alluding to), those distributions remain vulnerable.
Not having the module loaded doesn't mean you're not vulnerable, the kernel loads the module on-demand when it's needed. I tried the exploit on such a system, and it worked.
However, not having the module loaded does mean that in normal operation you don't need the module, so the proposed mitigation of disabling the module is safe in the sense that it won't disrupt anything.
I don't know what exactly can load this module but the servers are running for many weeks and I suppose that if something will load this module, it stays loaded until the next reboot.. no ?
I tried to rmmod on all servers and rmmod always returns `ERROR: Module algif_aead is not currently loaded`, that's why I think it's fine. Of course I take a look on https://security-tracker.debian.org/tracker/CVE-2026-31431 for the updates.
they disclosed 30 days after the patch was merged in the thing they reported to.
its the same disclosure policy as google's project zero, and several other major players, so you should probably be trying to ping a lot more people
reporters should not be responsible for finding out and individually reporting to every downstream consumer. blame the kernel security team, who is in a much better position to coordinate notifications to individual distro security teams.
The security research community would run you out on a rail if you tried to take a successful research product and attach mandatory disclosure norms to it.
For context, the author of the linked post, Sam James, is a Gentoo developer.
Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers. One would hope that the former would notify the latter, but apparently it's the responsibility of whoever finds the vulnerability.
i have no problem with disclosing a vulnerability 30 days after its patched in the thing you reported to. (in fact, for those unaware, this is the same policy that google's project zero uses: "90+30" https://projectzero.google/vulnerability-disclosure-policy.h...)
the real problem is:
>It's also worrying that it seems there's no communication between the kernel security team and distribution maintainers.
the reporter should not be the one responsible for reporting separately to every single downstream of the thing they found a vuln in.
what should be happening, as you allude to, is a communication channel between the kernel security team and distribution maintainers. they are in a much better position to coordinate and communicate with the maintainers than random reporters are.
the minute the patch landed in the kernel, a notification should have gone out from the kernel team to a curated list of distro security folk that communicated the importance of the patch, and that the public disclosure would be in 30 days.
> they are in a much better position to coordinate and communicate with the maintainers than random reporters are.
They openly refuse to do this and have been given authority by MITRE to work against any such process.
right, which is why it is confusing that the animosity is aimed at the reporters rather than the kernel security team.
Two things can be true simultaneously: the Linux kernel ecosystem should have done better at communicating this to their downstreams, and publicly sharing the exploit was irresponsible.
It is not the responsibility of the initial reporter to communicate to distributions, but the fact that those responsible failed to do that, doesn't give everybody else a free pass.
>publicly sharing the exploit was irresponsible
they did it in the established industry standard way that probably every single security researcher you can think of follows (for good reason, i would add).
whoever did the marketing on "responsible disclosure" was a genius.
tptacek says it much better than me: ""Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules."
In my world, responsibility is not just checking a box of following industry practice. Responsibility, as Wikipedia puts it on their social responsibility page, is working together with others for the benefit of the community. And yes, sometimes that's a bit larger burden than would ideally be the case. It's an imperfect world, after all -- and let's not forget the disclosure as it happened also placed a larger burden than ideal on people scrambling to patch.
And it's not as if I'm asking for a lot of effort. One mail to the security team of a popular distro "hey, we have found this LPE that we'll release with exploit next week, it's patched upstream already in this commit, but you don't seem to have picked it up" would likely have been enough.
No.
The problem is that vendors and developers have repeatedly shown that if you give them an inch, they take a mile. Look at exactly what happened with BlueHammer this month. The security researcher went full disclosure because Microsoft didn't listen to their reports.
Disclosure is vital. It's essential. Because the truth is, if a security researcher has found it, it's extremely likely that it's already been found by either black hats or by state actors. Ignorance is not actually protection from exploitation.
The security researcher also has a responsibility to the general public that is still actively using vulnerable software in ignorance. They need to be protected from vendor and developer negligence as well as from exploits. And the only way to protect yourself from an exploit that hasn't yet been patched is to know that it is there.
The situation with e.g. BlueHammer is fundamentally different: there, the only party that could act on it (Microsoft) ignored them. In this case, the parties that could act on it weren't notified at all.
I'm also not proposing delaying the disclosure to the general public at all. They already waited 30 days with that, that's fine. Just look a bit further than your checklist of only contacting upstream, and send a mail to the distributions if they haven't picked it up a week or two before.
No, this was already timed disclosure. This is very common and widely accepted. 90+30 is what Google Project Zero uses, for example. The security researcher has met their ethical requirements already. This is entirely on the kernel's security team for failure to communicate downstream. That is their responsibility.
The thing is, malicous actors are already monitoring most major projects and doing either source analysis or binary analysis to figure out if changes were made to patch a vulnerability. So, as soon as you actually patch, you really need to disclose because all you're doing by not disclosing the vulnerability is handing the bad actors a free go. The black hats already know. You need to tell the white hats, too, so they can patch.
If the maintainers were unresponsive, sure -- but it seems slightly hard to buy that a responsible reporter trying to make a big splash and a good impression wouldn't first check "did this make it out to the distros?" before making sysadmin's days real shitty, even if technically they could point fingers at other parties. At which point, if they're paying paying any attention at all to what they reported, they may have realized that a mistake was made.
its an industry standard disclosure process. 90 days after reporting, or 30 days after the patch lands, the vuln is disclosed.
the linux kernel team is in a 10000% better position to communicate to and coordinate their downstreams. it seems completely backwards to me to suggest that the reporter should be responsible for figuring out every possible downstream and opening up separate reports to each of them.
the kernel team should have a process/channel to say "this is important! disclosure is in 30 days" that is received by distro security teams. because this is not the first or last time the kernel will have a local privilege escalation. hoping that every reporter, forever in the future, will take the onus on themselves is a recipe for disapointment.
The problem is that if you make too big of a deal about a particular patch, then someone just reverse engineers the vuln from the fix and your responsible disclosure period doesn't exist anymore.
Gentoo has to take some blame too for not keeping all the kernels they maintain patched in a timely way.
you minimize this with the curated contact list.
the baddies are looking at every patch anyways.
Yes, it's just incompetence from everyone involved, not malice. The company making the disclosure doesn't actually care, and the kernel processes are ineffective.
No, it's incompetence from everyone involved except the company making the disclosure, which, despite the fact that the existing norms are not in fact binding (like people downthread seem to believe), they followed.
Really? It seems very odd to not check in on the status of the fixes, even if it's technically possible to pass the blame to other people.
Even if the only purpose of looking at the status to make yourself look good in marketing materials, it's surprising that it didn't happen.
One of the reasons this unavoidable deadline was invented, is that the alternative is that one company (or all of them) can simply decide to ignore the vuln report, and then the vulnerability will stay forever undisclosed and forever out there in the wild. And prisoner's dilemma suggests that most companies would chose "do nothing" in this scenario: they don't have to do anything, and if the vuln stays undisclosed, it probably won't be exploited anyhow. Win-win!
I'm confused. Can you explain how this applies to the current situation, where no vuln reports were submitted to the groups responsible for distributing patches?
> It was extremely irresponsible
As a user and admin I disagree. Makes one appreciate what a masterful bit of lexical-engineering “Responsible” Disclosure is, kinda like “Secure” (from me, not forme) Boot — “Responsible” Disclosure is 100% about reputation-management for the various corporation/foundation middleman entities sitting between me and my computer.
Those groups don't care that my individual computer is vulnerable but about nobody being able to say “RHEL is vulnerable” or “Ubuntu is vulnerable”. The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk than to be surprised by the fix and hope nothing bad happened in that meantime.
Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
So if I found a vulnerability that lets hackers withdraw withdraw all the money in your account without a trail on where the money went, you'd be fine with them disclosing it to the public at the same time as the bank learns about it?
Even when there is no known use case of the attack (other than the security researcher's)?
> The vulnerability exists for me either way, and I'd rather have the chance to know about it and minimize risk
By the time you hear about it, the money could be gone because 1000 hackers heard about it from the researcher before you did.
> than to be surprised by the fix and hope nothing bad happened in that meantime.
Hope is not a good strategy here.
Yep, I'd be fine with that. My bank has insurance, and my money would be returned.
Seeing your other (rightfully flagged) reply I want to tell you as a neutral party that yes this is missing the point of the analogy. You're basically saying "I would simply hit the brakes on the trolley". It's not that they're so hubristic they think it's impossible to legitimately disagree with their argument, it's that mentioning insurance is sidestepping their argument entirely. You're not addressing the general idea of getting hacked and suffering the consequences of the hack.
Just socialize losses and all is well.
What could possibly go wrong?
The banks cost of insurance goes up, cost of running an account goes up, how do we correct for this? offer worse accounts to customers...
Why do you assume banks would keep on doing the same old thing but paying more because of it? The cost would make them learn not to design systems where something like this hypothetical scenario was possible.
You're missing the point (not sure if you're just being dense on purpose...). If you're bank would just return the money then its not a good analogy. If someone gains root access to your machine, presumably they can do damage that can't be undone. In other words, to continue the bank analogy, they would take all your money and you would have no way of getting it back. Presumably, you would not be ok with this. And even if, for some weird reason, you were ok with that, 99.9% of all other people would not be ok with it.
Respectfully, I don't think they're missing the point. Banking, as an institution, has its flaws, but deposit insurance isn't one of them. These vulnerabilities exist whether or not they follow specific disclosure rituals, and systems should be deployed with defense-in-depth so that one privilege-escalation flaw is a recoverable event. Inventing tortured counterfactual analogies doesn't change the basic thrust of the poster's point: the account is insured, so getting drained by an attacker is not a fatal problem. Of course people should still take steps to prevent that from happening, but that doesn't mean prevention is (or should be) the only cure.
My point specifically is that some damage isn't recoverable if there's a vulnerability that gives someone root access. This makes the bank analogy inadequate in the first place. Im not trying to argue about whether deposit insurance is good or bad. Saying they would get the money back assumes the damage done to ones machine would be recoverable, which may not be the case.
My understanding is that FDIC deposit insurance only protects against bank failure, not fraudulent activity. Getting your account drained by an attacker may or may not be covered by a patchwork of other laws at various levels, and you could very well end up shit out of luck.
"I, personally am not affected, and I don't care about anyone else so therefore there are no consequences"
“The choice that maximizes potential damage isn’t irresponsible, because it means I can mitigate my own systems immediately.”
That’s what you’re saying here.
They're literally just restating the argument for full disclosure security. This is one of the oldest debates in information security.
The disclosure doesn't appear very "full". Looks like this was slipped into mainline linux among dozens of other mostly-irrelevant "CVEs" with nobody highlighting the fact that it is in fact dirty-cow-on-steroids.
https://x.com/spendergrsec/status/2049566830771970483
https://lore.kernel.org/linux-cve-announce/2026042214-CVE-20...
Or is everyone expected to upgrade and reboot every 48 hours for all eternity and just deal with potential regressions all the time?
I think this reflects poorly on the original reporters. If you have a weaponized 700-byte universal local root exploit script ready to go, perhaps you should coordinate with major distros for patches to be available before unleashing it on the world. No matter how "veteran" you are.
Um, yes, everyone is expected to upgrade and reboot on a moment's notice. No policy or norm you come up with will change that.
(This bug does not technically require a reboot to mitigate).
I think I must misunderstand. Are you saying that you upgrade and reboot every production system that you administer to apply each commit to the kernel (branch it's using) essentially immediately? That doesn't make sense to me for a few reasons, but I struggle to find a different reading that applies "upgrade and reboot on a moment's notice" to the "slipped into mainline linux" scenario. Kindly help me to do so.
No: your posture with respect to having to cycle servers is a super complicated subject and you address it both with process and with architecture (for instance: you can be blasé about things like CopyFail if you don't allow multitenant shared-kernel in your design in the first place). But no matter what process and design you have, if you're hosting sensitive workloads, you always have to be in a position where you can metabolize having to cycle your servers.
It's a category error to talk about a disclosure event like this as something that would destabilize someone's fleet operations. The Linux kernel is fallible. So is the x64 architecture. You already have to be ready to lock things down and reboot (or mitigate) at a moment's notice.
Remember: whatever else grumpy sysadmins have to say about this, Xint are the good guys. Contrast them with the bad guys, who have vulnerabilities just as bad as CopyFail, but aren't disclosing them at all --- you only find out about them when it's discovered they're actively be exploited. There's no patch at all. There isn't even a characterization of how they work, so that you could quickly see what to seccomp. That's the actual threat environment serious Linux shops operate in.
LPEs are not rare.
Oh, I thought you meant "everyone" in a sense including actual human persons and the devices on their home network.
I find it curious to call someone dropping a weaponized root exploit before major distros or even LTS kernel git branches have patches ready "good guys". This could have been handled with much more grace.
What the heck is up with people today.
Using quotes around something where you’re actually doing a strawman paraphrase of another commenter you disagree with is bad form.
> Immediate public disclosure is the only choice that isn't irresponsible as far as I'm concerned.
No, it's really not.
High severity vulnerabilities are responsibly handled by quietly neutralising them with subtle patches that do not reveal the vulnerability, waiting for those patches to distribute. Then patching or removing the root cause of the vulnerability (at which point opportunists will start to notice), and finally publicly disclosing it when there are already good mitigations in place.
Example: spectre/meltdowm mitigations.
I've been asked to use this approach myself when reaching out to maintainers. Sometimes it's possible to directly fix the vulnerability as a "side effect" by making a legitimate adjacent change.
With immediate disclosure the provider can decide to shut down while it is fixed. Or to notify users and make it their decision. Or to be prepared with a diversified infra and switch over to a non-vulnerable path. e.g, BSDs are not affected by CopyFail
Those groups care about whether millions of computers are vulnerable, likely including your computer. If "immediate public disclosure" was done in all cases every vuln would be exploited and patches would be much lower quality. Shortening the disclosure timeline might be a good idea, 90 days is starting to feel long.
Millions of computers are still vulnerable. Not-knowing about it doesn't mean the vuln isn't there :p
The Venn diagram of mainstream distros and individual Linux users is virtually a circle.
Ubuntu/RHEL is vulnerable and so are most Linux users by extension.
The disclosure was more about marketing than security. From the disclosure page:
> Is your software AI-era safe?
> Copy Fail was surfaced by Xint Code about an hour of scan time against the Linux crypto/ subsystem. [...]
> [Try Xint Code]
More chaos makes their product seem even more attractive.
I worked at the industry's first commercial vulnerability lab (Secure Networks) in the mid-90s, and many of my friends at the time founded X-Force. Commercial vulnerability research has always been about marketing: marketing pays for the vulnerability research. That doesn't make it any less prosocial.
Your advertising for them on HN would help them too, I bet.
Does it? Now that I see their name again in this context they're blacklisted for life.
hope you are also blacklisting google's project zero, and practically every other major player in the vulnerability reporting space, as all use roughly the same bog standard 90+30 policy.
this was a failure of the kernel security team, and their stance on communicating security issues with their downstreams.
Same. They do become famous, but not in a wholly positive way.
I used to think the context of the fame mattered. At least in the US, it does not.
Hell, Crowdstrike is still purchased.
Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all. Be glad a patch was available prior to release.
If they want to be seen as responsible rather than opportunistic, then yeah, they should do a proper coordinated disclosure.
Sure, they have no legal obligation to disclose, but we all also have no legal obligation to buy their services. Blacklisting bad actors like this is the right move to discourage this kind of behavior.
>they should do a proper coordinated disclosure.
they did a proper coordinated disclosure, following the industry standard 90+30 process. that is why the exploit dropped 30 days after the patch landed.
the kernel team should have communicated with their downstream about the importance of the patch. that is the kernel security team's responsibility -- and they are much better positioned to do that than crossing your fingers and hoping every reporter will contact every distro every single time there is a vulnerability.
there are very good reasons disclosure works this way, backed by a couple of decades of debate about it.
Who cares about how you are seen when you are selling 0day for big bucks? The bad actor makes more money than the 'legitimate' one without breaking any law. Punishing someone who didn't alert distros despite a patch being available encourages the company to simply find flaws and sell them for profit - it pays more to begin with.
If they want to take advantage of disclosure for marketing, they're either going to need to accept the norms around responsible disclosure, or they're going to need to accept how shirking those norms will come off. That's life in society. Sometimes it's annoying and sometimes it doesn't feel rational, but these norms have been negotiated throughout the history of our industry and are the way they are for reasons good and bad.
I just don't see the point in complaining about how shirking the norms of your industry will make you look irresponsible. I don't really care that they could have decided to sell the vulnerability instead. It isn't material.
It is absolutely not true that viable commercial vulnerability labs need to "accept the norms around responsible disclosure". There are no such norms. "Responsible disclosure" is an Orwellian term cooked up between @Stake and Microsoft and other large vendors to coerce researchers into synchronizing with vendor release schedules. It was fantastically successful at that, and it's worth pushing back on at every opportunity.
Tavis Ormandy dropped Zenbleed right onto Twitter. He's doing fine. You can blacklist him if you want; I imagine he's not going to notice.
Microsoft's policy is: "if you contact us with a vulnerability, you automatically agree to the terms of our responsible disclosure policy", which includes waiting 30 days after patch was created, and says nothing about how long that process takes.
There is actually no way to give them a friendly heads up, and then do your own thing. The only way not to be bound is by not sending them any notification at all...
Since no contract is signed, this is just pure fantasy from your part.
I wonder if "if you contact us... you automatically agree" stands in court. That's just ridiculous.
Reader, it does not.
You're right, they don't need to. They have an alternative, to accept what people say or think about them in response. That's what I said.
Those norms do not exist. Those are people asking companies to do stuff to benefit the person complaining for free, and many companies will not do that.
It seems to me you're unaware of them, but there are strong norms around disclosure. They've been discussed for decades. It is the expectation that vendors would be notified in a scenario like this.
No, there are users who want those to be norms. Qualified researchers happily sell substantive vulns to people who pay (Governments/Cellebrite and companies like that) enough to quell any complaint.
Which is again, irrelevant to the question of how disclosure works and what expectations there are around it because that is not disclosure and is not what was being discussed.
it’s called building and preserving a high trust society, you wouldn’t understand
Unfortunately this is correct. As a security researcher I set millions in profit on fire for reporting vulns to projects that offer no bounties vs selling to highest bidder. I keep doing it because it is the right thing to do, but I would not blame someone that needs to feed their family making a different choice.
We must get public funds to reward ethical disclosure of big impact vulns like this.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit. Just fyi. Be glad it was disclosed at all.
I'm so glad these so called "researchers" aren't totally evil, I'm so grateful they're only half evil, give them a lollipop.
Whatever, the way they disclosed it isn't much different from no disclosure at all - the exploit would have been identified in the wild and fixed soon thereafter.
"Researchers"...
the way the disclosed it is the industry standard. think of the biggest security research teams you know (e.g. google), and they follow the same process.
non-security people always seem to get up in arms about it, but there is very good reasons why the industry has landed on the process it has, which has been hashed out over a few decades.
> are free to sell 0day for profit.
This is not true in many jurisdictions.
Anyone can sell a vuln in any jurisdiction and never be caught. Lets not pretend the law is actually worth a damn here.
We need an anonymous bounty system.
I'm pretty sure they have a legal obligation in most jurisdictions not to sell 0days for profit.
And they absolutely have a moral obligation to do things in a way to minimize damage and impact to other people's systems. (I'm not saying "responsible disclosure" is the correct way to do that, but hoarding vulnerabilities and exploits and selling them to the highest bidder certainly isn't.)
This is how society needs to work.
Let me make you aware of zerodium. A broker anyone can sell vulns to, that sells to unspecified buyers you do not need to know about.
> I'm pretty sure they have a legal obligation in most jurisdictions not to sell 0days for profit.
it wasn't sold for profit, it was openly disclosed.
> And they absolutely have a moral obligation to do things in a way to minimize damage and impact to other people's systems.
All that "responsible disclosure" does is keep people from demanding better.
mmmmmm, no it would seem like they are absolutely under a social obligation to not do that.
> Researchers are under no obligation to engage in coordinated disclosure and are free to sell 0day for profit.
Uh... no? If you mean legally, some people might, depending on jurisdiction. But also, ethically? yes, researchers are ethically obligated to disclose responsibly.
> Just fyi.
...
> Be glad it was disclosed at all. Be glad a patch was available prior to release.
I am glad that a patch was available. Equally I can be glad that the linux community is strong enough to respond quickly, while also being angry that this person behaves unethically.
Likewise, when people in my industry behave poorly, or unethically; I'm now the person ethically obligated to both point it out, and condemn it. Not to become an apologist demanding I should be happy watching bad things happen, when much of the fallout could have been prevented with a bit less incompetence and ignorance.
They should have a legal obligation to engage in coordinated/responsible disclosure, and it should be a crime to sell or disclose a 0day to anyone other than a state-designated security organization or the vendor/provider.
If it won’t be handled through criminal law then it’ll be handled through civil litigation: Anyone who was exploited as a result of this disclosure should sue the discloser for contributing to the damage they’ve suffered.
Yes, exactly. Name and shame.
Same. I did not know who they were, but now they have been named and shamed. Not every publicity is good.
The notification happen when the fix was shipped. That people would prefer to been spoon fed only serious security issues is understandable, but not realistic.
A large percentage of kernel fixes have the potential to be similarly bad. For some the potential isn't even realized until after the fix has shipped.
Ever stable release GregKH says you must upgrade now, because there is something security relevant in there. This happens at least once a week.
As for shared hosting providers it is my sense that there is always at least one local privilege escalation available to miscreants. Making shared hosting only safe if there is a certain amount of trust.
I remember bugs that were similarly bad from my university days 30+ years ago. Has anything substantially changed?
The Linux kernel is not usable as a security boundary, so anyone who wants to do "shared hosting" and not be hacked needs to use something else, like gVisor or firecracker VMs
The only important system that uses it as a security boundary is Android and there is mitigated by the fact that APKs need user approval, plus strict SELinux and seccomp policy plus the GrapheneOS hardening, and in this case the mitigations succeeded (https://discuss.grapheneos.org/d/35110-grapheneos-is-protect...)
A LOT of websites are tenants on WHM/CPanel hosts. Not to mention how many agencies use it for their clients Wordpress sites.
I'm quite sure there are many application hosting providers which rely on container runtime such as runC (default runtime of containerd/Docker), and a shared kernel between users.
In a just world, those companies would be held legally accountable for negligent practices. The Linux kernel upstream has made it clear for decades that security is a dirty word.
LPEs on Linux are obscenely commonplace.
Without taking a position on the disclosure mechanics: any hosting provider hacked with this was already playing to lose. It is not OK to run competing untrusted tenant workloads under a single shared kernel. Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity.
> Kernel LPEs are not rare. This was a particularly simple and portable one, but the underlying raw capability is a CNE commodity.
I absolutely 100% agree with this and I'm glad to see somebody saying it. Any system that is one LPE away from being compromised is already insecure.
Expecting people to do the right thing is a fundamental issue here. Why would you ever expect for all of vulnerabilities to be disclosed privately? There's very little actual incentive to do this.
I'm honestly unaware of what systems could be put in place to prevent this but expecting people to always do the right thing is fantasy level thinking. I mean I bet the disclosers thought they were doing the right thing, hence why it's a bad thing to rely on.
edit: spelling/grammer.
When the exploit is an advertisement for an exploit detection company, not doing the right thing is a bad look
The worst thing would be to exploit or sell it for profit. Instead of that, publicizing the exploit is closer to neutral–good in my books, that did trigger a really quick reaction from the different actors to patch their kernels and systems
Imagine how much quicker the distros would have reacted if they were given a heads up a month ago. But, sure, I guess kudos to this company for not being actively criminal, and merely bumblingly incompetent and overly eager to get their marketing pitch out the door.
Why don't all these distro maintainers add their own back doors, and mine crypto off our machines without our knowledge? Surely, there is some legal fine print they can add that would let them do that. There is very little incentive for them to maintain these systems, given how thankless and underpaid the work is.
I can accept (and welcome) disclosure before there are patches.
But publishing a working exploit together with the disclosure before patches are available is really really irresponsible, maybe even criminal.
And no, the proposed mitigations don't help with half of the distributions out there...
The patch was available. Upstream just doesn't communicate vulnerabilities because they have a personal dispute with distros about how to handle patching.
AIUI the exploit was fairly low-effort once you knew the vulnerability. So publishing one probably didn't change the landscape much.
> maybe even criminal
What’s your theory here? What crime?
Exploits are sold and used as weapons, sometimes even weapons of war. Which in many places is criminal, except under very restrictive circumstances.
Also, all kinds of aiding and abetting.
What does that have to do with this comment thread?
Copying from the comment I was replying to:
> But publishing a working exploit together with the disclosure before patches are available is really really irresponsible, maybe even criminal
If it's not a crime I see no reason not to work with partner nations to build responsible disclosure into a legal framework everywhere because it pretty obviously should be.
If you wanted to somehow make coordinated disclosure into a legal framework, that would be an interesting and complex project.
But it’s not the law anywhere I’m aware of today, and I’d not support it becoming a law.
You know companies are allowed to pay people to find vulns, and pay people bug bounties?
Instead of that, you’d rather make the law compel free individuals to limit their speech, or to hand over their work to big companies privately, so big companies can save money?
That doesn’t sound like a nice future, if it’s even enforceable at all.
There is an alternative mitigation you can use which blacklists the function calls when the affected code is not built as a kernel module.
Patches were available for nearly a month.
Basic care would involve making sure the patches had made it into the wild before ending the embargo, and nagging the relevant parties if not.
Edit: As of this writing, most distros including Redhat, Fedora, Debian Stable, do not have patches available in the package repos, though they're being actively worked on.
Not true, if there’s any evidence of the exploit being used in the wild, it’s much more responsible to release immediately.
Considering that the patches have been available for a while, someone surely reversed what they were for and was actually exploiting this in the wild.
In the age of AI, I’d argue that “responsible disclosure” is dead. Arguably even in closed source projects. Just ask Claude to do a diff between the previous version and to see whether anything fixed in there could have had security implications.
We’re not there yet, but very soon the only way to responsibly disclose a vulnerability will be immediately.
But they didn't release immediately -- they waited a month, but forgot to tell the distros, and forgot to check if waiting a month had actually lead to distros picking up the patches and shipping them.
“Made it into the wild?” Patches landed a month ago. Should they also wait until my linksys router from 2018 has a patch ready?
Patches are still in the process of landing in most major distros as of the time of this writing. Most users are not able to get an update through their distro's packaging mechanisms.
It's a local vulnerability at least. How many people do you let log in to your router?
With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited. Even with shared hosting, you generally have root in your VM or container anyway. Unless this enables an escape from that?
Still the risk that people who run "curl | bash" without care could get bitten, but usually its "curl | sudo bash" anyway...
> With the way linux is used these days, I'd guess the number of systems with untrusted local users is pretty limited
Things like HPC clusters are multiuser & don't entirely trust their users. If they did we wouldn't need users/groups/permissions etc in the first place.
Yes. Not even just HPC clusters, shared login servers are pretty common in academia. I manage several in our lab. Sure, we mostly trust the users against malice more or less but not so much against incompetence. A malicious vscode plugin would run rampant in this space.
And then there are users running claude-cli and friends who may just find it convenient to use a local root exploit to remove obstacles.
> Even with shared hosting, you generally have root in your VM or container
Lots of shared hosters don't use VMs or containers. It's some arbitrary number of people logging in to a shared system, each one with a home directory under /home/THE_USER_NAME. i've had several such hosters over the years (thankfully not right now, though).
With this exploit it's trivial to jump from one container to another neighbor container. I've tried it and succeeded.
So containers don't protect you, only a VM.
So anyone pulling a malicious dockerfile jeopardizes the host? That would be bad...
...no shit? Why do you think people care about this issue?
Local root is part of the path to escaping
That's mostly on Greg, a bit on the author.
Fedora is patched.
only for versions 6.19.12 & 6.18.22. older versions (which are used in distributions) are not ready yet.
Why wouldn't the linux security team notify the main linux distributions?
Greg and Linus do not believe in the entire concept of "vulnerabilities" in the Linux kernel and do not believe in the methods that distros use like cherry picking, therefor they typically are against issuing CVEs, scoring CVEs, describing vulnerabilities at all (if you use the word "vulnerability", your patch will be rejected), etc.
It's fundamentally their position to not work the way that you describe.
That doesn't really seem to map onto the situation since Greg himself released a 6.12 with the patch earlier today.
I don't know what you mean at all. I'm just repeating known kernel policy here. What does 6.12 have to do with anything?
Well, how do you define main Linux distros? Isn’t the next smaller one not receiving the info always complaining?
Isn't there already a distro security list for this purpose?
Yes.
Because one of them might have an incentive to not do so. In this case it's because they want to advertise their own company.
Partly they already have enough on their plate. It's up to the reporter to pick how to handle the disclosure, and unless a specific maintainer chooses to handle it, the Linux security team clearly says they won't.
Partly they have a strong belief that all kernel bugs are vulnerabilities and all vulnerabilities are just bugs; sometimes taken to the extreme in both ways (on one hand this case where the vulnerability is almost ignored; on the other hand, I saw cases where a VM panic that could be triggered only by a misbehaving host—which could just choose to stop executing the VM—was given a CVE).
This couldn't be more backwards. This has literally nothing to do with bandwidth. The kernel is a CNA, they are explicitly the ones to do this.
The reason they don't is because Linus and Greg have repeatedly, publicly stated that they don't want to because they don't believe that vulnerabilities conceptually make sense for the linux kernel and they refuse to engage in the process.
Seems a little crazy. Somebody should evaluate blast radius and do appropriate distro notifications in a case like this (I presume the impact was part of the disclosure, so not much extra work).
You know the linux kernel is a free software project right? If you think “somebody should” do a thing but you aren’t prepared to do it yourself then you should maybe ask for a full refund.
Thank you very much, seanhunter. You hit the nail on the head there.
I think it’s reasonable to expect folks in the security community who go to the trouble of creating a website detailing security vulnerabilities in specific listed software to pre-notify the security teams of that software. The CopyFail website calls out Ubuntu and Red Hat specifically, but apparently the author of the site did not inform them of the issue?
But even if you think making unethical decisions in personal self interest is something no one should be criticized for, surely the Linux kernel team ought to have some process for notifying the top distributions of an upcoming LPE, just out of practicality.
In what sense do you believe that the reporter did not notify the security team of the relevant software? The vulnerability is in the kernel. Reporter responsibly disclosed using the kernel’s security report mechanism and waited until a patch was ready.
Distros are downstream of kernel, that doesn’t entitle them to expect to be contacted directly by every security reporter. That’s not on them. Distros that are big enough should be plugged into the linux security team for notifications.
Security researchers cannot be held responsible for broken lines of communication within the org charts of projects that they study. They’re providing a valuable public service already, how much more do you want?
It is suggested that they out of an abundance of caution and 5 or 6 emails. If this is entirely to much to expect we can always help them by mandating that they spend 6 figures annually meeting a much more robust set of requirements that will include notifying all possible affected parties down to Hannah Montana Linux devs if any still exist.
Any strategy that assumes that the rest of the world is functional or makes you personally responsible for fixing all of it is equally broken but there is a reasonable middle ground and sending a few more emails lies within it
AWS and GCP are downstream another level. Should the reporter also have worked with them? And their customers? And the customers of their customers?
IMO this whole discussion seems like people are annoyed by the security researchers doing god’s work and wish they didn’t exist or think that they should be fully subservient to the projects and companies they are helping for free. The bugs were there before the researchers revealed them!!
> that doesn’t entitle them to expect to be contacted directly by the reporter
Yes it does. That's how it's always been done and distros can ship a fix well before it ends up in a kernel release.
> expecting people to always do the right thing is fantasy level thinking.
Most people in tech think like the techie in this comic strip.
https://xkcd.com/538/
> Who knows how many shared hosting providers were hacked with this.
I'd consider a shared hoster which allows users to run their own (native) code and doesn't use VMs for tenant isolation extremely irresponsible in 2026.
This is probably more common than you think. VMs are expensive, both in resources and cost (if you’re using something commercial). OS-level isolation (shared kernel, cgroups, namespaces) is used pervasively
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
It's a total arsehole'y move to not share with open-source projects (like Debian) but for commercial vendors like Microsoft I don't give a crap.
Now let's not get carried away either: that's a privilege escalation, so it already requires access to a local account. We're not exactly in Jia Tan "I backdoor every SSH out there if your Linux distro is using systemd" territory either.
Who knows how many attackers had found this vulnerability and had already been using it prior to this research finding it?
Argument from uncertainty is not a good way to reason about this.
I could equally ask: "Who knows how many attackers learned about this vulnerability from this disclosure, and used it before the distributions fixed it?"
Yes, you could. Thats the core of my point: there is no Right way to handle vulnerability disclosure. There are many competing factors, most of them have major elements of uncertainty because you can’t know who knows what or how various projects or stakeholders will react.
So maybe folks should take a break from the kind of armchair quarterbacking that this was “incredibly irresponsible”, as was done upthread, or that the researchers should be blacklisted for life, as a parallel commenter stated.
well now everyone does, so the irresponsible disclosure makes it significantly worse.
It’s your opinion that it’s irresponsible and that it makes something worse.
and its your opinion that it doesn't. Shall we continue stating the obvious? We are communicating using glyphs. This language is English. We are on Hacker News. This branch of the conversation is extremely unproductive.
I asked a question and you replied with a statement. Your statement didn’t frame itself as an opinion but as fact.
The hilarious bit is that the idea that they needed to coordinate is clearly broken even in just this example. They did give prior notice to the Linux developers, who issued a patch. And they’re still getting raked over the coals in this comment page by armchair quarterbacks who have decided they needed to coordinate with specific distros. If they’d coordinated with those distros, somebody would have a pet distro that didn’t make the cut and they’d be pissed about that.
There are risks no matter how they do it, and there will be people who are pissed no matter how they do it. Security researchers don’t owe anybody a specific methodology.
you seemed to suggest with your initial statement that any disclosure was acceptable as people would have been using the exploit prior to the disclosure. I don't think that's a strong argument given now the initial people who were using the exploit prior to disclosure are now joined by people who have learned of the exploit as a consequence of the disclosure happening before all the distribtions were ready.
So I feel like the argument reduces into "why is it a problem that now anyone could exploit it, if some people were exploiting it already". Which imho isn't a sensible argument because the issue is clearly the amount of people capable of using the exploit for nefarious purposes, which has increased.
Idk why you felt the need to use quotes to wrap something I didn’t say, and that is a pretty uncharitable attempt at reframing my question. If you wanted a quote, here’s what I’d say:
“Because we can’t know if there was exploitation by existing parties who had discovered the vulnerability on their own, there are upsides to disclosing earlier so that affected users can take mitigating steps and review their systems for indicators of compromise. Additionally, the more projects the researchers pull into the loop for coordinated disclosure, the higher the likelihood that they further leak the vulnerability to more attackers.”
Idk why you felt the need to use quotes to wrap something I didn’t say. Despite the fact I didn't say that, its a much more interesting argument than your original statement implies and it is unfortunate we didn't start there.
However the issue is that we cannot know if the attack space has been broadened or lessened as a consequence of this disclosure, because of how eager it was. If it wasn't eager then we could much more comfortable in suggesting that the attack space has probably been reduced.
Given the exploit had been living in the linux code base undetected for so long in the first place, I think its fair to state that disclosing the exploit prior to the distributions being ready and given the distributions are the principal attack vector of the exploit: that the researcher has made the situation worse and should reflect on their actions.
… I used quotes to wrap something that I was saying. I even called out that it was something I was saying, as a more accurate variant of what you’d claimed I meant.
and I prefaced my quotes with the statement "So I feel like the argument reduces into". I mean, idk what punctuation I'm supposed to use there that doesn't offend you, but I just figured we can all read words and it was clear that I wasn't saying you said that, but rather, as I read the argument it was reducable to that and I took issue with that potential reduction.
The idea about the available exploit space and how the actors within it might, or might not move is a much more interesting avenue of conversation and I thank you for elaborating on your initial comment. <3
I do however feel that its hard to be confident about whether or not the attack space has been increased or reduced as a consequence of the eager disclosure. I feel we could make the case either way.
The public disclosure page has a big blue "Get the exploit" button.
It's an advertisement for an unpatched critical exploit and apparently some kind of infosec company.
At least thankfully workaround is one line in a file.
The title on this post was changed to imply that only the Gentoo developer was left out - which I could believe.
> Who knows how many shared hosting providers were hacked with this.
None? Because nobody* does hosting using Linux users as a security boundary. It's not the 90s.
* Standard HN disclaimer for people that think that some retro shell box with 10 users disproves "nobody": nobody does not literally mean exactly 0 people in this context.
Counterpoint. End users have a right to mitigate this issue on their systems.
It is a really really bad look for Linux, puts a bit of water on all hype around switching from Windows.
It does? The disclosure even says the concern for single user systems is very low. If someone has access to your single user system, remote or otherwise, you’ve already lost on the sort of device people would be switching from windows to Linux on.
> The disclosure even says the concern for single user systems is very low.
For single user systems (not rigorously defined, I presume it's the intersection of our two definitions which we might be talking about) the nature of the exploit is local privilege escalation, of which there could be many possible, and many mitigations / countermeasures against. This could have suddenly appeared from the ether of "unknown unknowns" for some people.
Those people farther up the food chain still potentially have service accounts, maybe even user accounts for some purposes, perhaps "trusted" services which deliver them code which they deserialize and run once. (Have a pickle.)
severity * impact * likelihood
Not everyone looking to migrate from Windows 95 plans to run everything as root afterward.
On the copy.fail site:
Not everybody needs or wants to wait for their distro, or plans to patch their IC firmware when a config change will do.Someone like an AI coding agent perhaps ? This is the type of thing Prompt injection was made for.
No OS is perfect. The awkward rollout for this bug fix is proof of that.
Root access does not typically add anything interesting, for a desktop system. All the valuable stuff is already owned by the single user.
Imagine an ignorant response like this from Apple? One of the most short sighted comments I've seen on HN in some time. And the double down! A true master class in misunderstanding the issue and the entire FOSS ecosystem in two sentences.
As opposed to all other operating systems with no CVEs ever?
Hype around switching from Windows servers?
What happens if someone does the exploit in WSL?
>> puts a bit of water on all hype around switching from Windows.
Said no one ever...present post excluded :-))
You clearly have no idea how often windows has unpatched privesc exploits.
> Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix. Who knows how many shared hosting providers were hacked with this.
Maybe it is irresponsible how little attention we pay to software security. Maybe, software developers of all kind should spend an entire year not developing any features at all, but fix all the tech debt of 30 years instead.
Yes, that sounds revolutionary, but I do not see an alternative in an age where all you need to find kernel bugs of this scale with AI agents.
>> Anyway, this is a disaster. It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
Maybe a decade of corporations with revenue in the billions, paying peanuts and coffee money, for critical vulnerability disclosures made it....
> It was extremely irresponsible to share the exploit with the world before the distributions shipped the fix.
Yes, this was clearly a marketing stunt to promote Xint code.
I, for one, will never use Xint code and will advise everyone to never use it. To anyone working there: enjoy your 15 minutes, I hope this backfires right in your face.
> Note that for Linux kernel vulnerabilities, unless the reporter chooses to bring it to the linux-distros ML, there is no heads-up to distributions.
Why would they imply it is incumbent on the reporter to liaise with distributions? That seems to assume a high level of familiarity with the linux project. Vulnerability reporters shouldn’t be responsible for directly working with every downstream consumer of the linux kernel, what’s the limiting principal there? Should the reporter also be directly talking to all device manufacturers that use Linux on their machines?
IMO reporter did more than enough by responsibly disclosing it to linux and waiting for a patch to land.
Aren’t there people in the linux project itself with authority over and responsibility for security vulnerabilities? One would think they would be the ones notifying downstream distros…
Especially since the reporter is explicitly asked not to notify the distro teams first.
https://docs.kernel.org/process/security-bugs.html
```As such, the kernel security team strongly recommends that as a reporter of a potential security issue you DO NOT contact the “linux-distros” mailing list UNTIL a fix is accepted by the affected code’s maintainers and you have read the distros wiki page above and you fully understand the requirements that contacting “linux-distros” will impose on you and the kernel community. ```
I don't get why the initial reporter should have to do that legwork. The kernel maintainers should be doing that.
The kernel team has been at odds with the CVE process and the oss-security community about this stuff for many, many years now. It's a big part of why the kernel team established a CNA and started flooding CVE notifications; they don't believe that security problems are different than non-security problems, and refuse to establish norms or policies based on the idea that they are.
It's such a bizarre viewpoint. I wonder when Linus will see sense.
IMO it's pretty obviously not a view that they seriously hold, it's just one of those technical justifications people come up with to avoid admitting something they don't want to admit - in this case that Linux has a poor security track record.
> I wonder when Linus will see sense.
Literally never. Why would he? He's surrounded by sycophants. And we have Greg for whenever Linus isn't involved anymore, and Greg is just as boneheaded.
The reporter took time to check and mention on their website specific distributions Ubuntu/RHEL/SUSE. One would have thought reporting to security teams of at least those would be responsible.
“One” would have thought? Can you point to a written policy that says that’s how it should be?
No, nor can I point to a written policy that states one should cover one’s mouth when they cough.
Everyone involved here failed to do the right thing, and hiding behind the lack of written words is weak sauce.
The tenets of decency don’t need to be written down.
If you can't write it down, why would you expect it to be universal and enforceable? Different cultures exist and have different opinions on what "decency' means, after all.
A security researcher's ethical obligations are to protect users over vendors (barring any contractual agreement in place). From what has been discussed in this thread, they meet that bar.
Sure, they could have gone the extra mile to ensure the distros were in a good place to patch before they published the exploit. That's a kindness you can wish for, but don't disparage them for not going that extra mile. It's a bonus.
It's also possible that it simply didn't occur to them to do so this time. There's certainly lessons to be learned either way. I don't know that the right lessons will emerge from hostility.
> If you can't write it down, why would you expect it to be universal and enforceable?
and this is the problem. It used to be the case that if you were smart enough to find an exploit you were also smart enough to realise what would happen if you irresponsibly disclosed it. I guess these tools have made that pattern no longer apply.
From my point of view, they told the kernel security team which is in charge of fixing this. If it’s important for them to tell other people, then it should’ve been written down and further reiterated when they made their report.
The skills to detect code exploits is not the same as the skills to navigate an informal org chart to the satisfaction of an amorphous audience if end users (i.e. us on HN).
That said… as they are a company that supposedly specializes in this field, and is trying to sell a product, I do believe they should do better. Right now, I don’t have much confidence in their product.
different cultures have different views on disclosing vulnerabilities to distros before the public?
Yes :) The blackhatter would obviously sit on it until they can sell it or use it, the whitehatter collaborate the kernel and distros to patch, and the greyhatter argues on HN whether the latest *fail was responsible enough or not.
Yes? "Different cultures" doesn't just mean different countries; there are many cultures within infosec.
There is little difference in culture here. Nearly all open source work is done in English.
Sure, maybe it's not a _requirement_, but now we're all in more pain because the reporters are more interested in Fame than Safe Remediation.
No, you're in more pain, but other defenders with different postures benefit from having faster and fuller disclosure.
Mind explaining how sitting on it a month after the patch landed is 'faster'?
The reporter made a website explicitly calling out Ubuntu, RedHat, Amazon, and SUSE but didn’t notify them, and you think that’s reasonable? That they might not have known those distributions are downstream from the kernel team?
If you notify the kernel and they ship a fix, it seems reasonable to expect that they will communicate the fix to the distros.
I see this as an organizational failure of the Linux ecosystem. There should be better communication between distro and kernel development.
What is the heuristic for who should get the heads up? Should they notify amazon but not google simply because they named amazon linux in the report? Seems to me the answer to my first question gets messy fast.
it's trivial to find out how to report a security issue like this to Linux distros.
Google search: https://share.google/aimode/eihDKXZJy94Z5lC1p
and it's beyond me to not think about doing this and instead exposing everyone and their neighbor to this exploit up front.
I'm certain this is even a felony in some legislations, rightfully so.
Agree it's not a good look for these folks, notwithstanding that disclosure is mostly theater.
Stop blaming the reporter. Start asking kernel to fix their process. Linux kernel is no longer a toy project, it has full time employees employed by various companies. They should have handled notifying distributions. Not some rando.
Just for what it's worth, I just pushed an eBPF-based workaround for people who are running kernels in which AF_ALG is linked directly into the kernel and not as a module: https://github.com/Dabbleam/CVE-2026-31431-mitigation
I am running this in production right now and it mitigates the attack, with no unexpected side-effects as far as I can see.
`nosuid` and probably `nodev` should IMO be the default filesystem mount options. `/dev` is already a special devtmpfs and the initrd minimal /dev can just explicitly mount the initrd tmpfs rootfs with `dev` and `suid` if necessary.
Letting SUID binaries just "exist" anywhere is a stupendous security issue. What if you mount some external storage medium, how are you to verify that none of the SUID binaries on that block device are malicious.
Additionally, this exploit appears to only work if the user executing the SUID binary can also read the SUID binary. There's no reason for non-root users to have read on a SUID binary.
NixOS does this correctly. No SUID in the normal package installation directory `/nix/store` and no package leakage outside of that no `nosuid` can safety be used on all other mountpoints. The exception is just a single-purpose `/run/wrappers.$hash` directory that safety contains executable ONLY SUID wrappers.
While I hate suid as much as the next person, it's really not the problem here.
The bug that is being exploited gives you basically arbitrary page cache poisoning. At that point it's already game over. Patching a suid program is maybe the easiest way to get a root shell from that but far from the only.
The proof of concept exploit is just that. It is meant to demonstrate one attack vector only. There are many others. If your goal is to prevent the conceptual exploit only then there are many easier ways to accomplish that, such as blacklisting, that does not make you safer.
With this vulnerability you can manipulate the page cache. You could also manipulate ld.so to hook into arbitraty system calls, or set your uid to 0, or any of another dozen or so ways to elevate your privileges.
Mount points have nothing to do with this, even if is always a good idea to disallow suid in user writable areas and prevent reading suid files, but that's for other reasons. NixOS does nothing to fix this and is just as vulnerable as everyone else.
Without read permissions you cannot execute the binary, that would not make any sense.
To execute the binary it needs to be read from disk and loaded into memory.
In fact if you have read permissions but not executable permissions on a specific binary then you can still execute it by calling the linker directly /bin/ld.so.1 /path/to/binary (the linker will read and load the binary and then jump to the entry point without an exec() call)
> Without read permissions you cannot execute the binary
This is not correct, as when the binary is setuid-someone-else, you are not the one executing it; they are.
Removing world-readability from all setuid-root binaries on the system would be sufficient to kill the PoC script provided for this vulnerability. It would not be sufficient to prevent exploitation though; there are many ways to abuse the ability to write to files you have read access to in order to gain root, for example by using the vulnerability to alter the cached copy of a file in /etc/sudoers.d/, or overwrite /etc/shadow, or /etc/crontab, ... the list goes on.this ld.so magic will lose the suid bit
loader
Neither was NixOS.
https://discourse.nixos.org/t/is-nixos-affected-by-copy-fail...
None of the distros were.
The Bleeping Computer link below mentions a potential remedy until a patch is ready.
https://www.bleepingcomputer.com/news/security/new-linux-cop...
This workaround only applies to kernels with the impacted code compiled as a module. RHEL, Fedora, and Gentoo (we use a modified Fedora config) all are configured to build this in directly. Without a patch or config change (as Sam from Gentoo was alluding to), those distributions remain vulnerable.
There was some discussion on the GitHub issues about workarounds to disable it, even though it is baked in.
https://github.com/theori-io/copy-fail-CVE-2026-31431/issues...
https://github.com/theori-io/copy-fail-CVE-2026-31431/issues...
This worked as a mitigation on distros with the module compiled into the kernel: https://gist.github.com/m3nu/c19269ef4fd6fa53b03eb388f77464d...
Basically: sudo grubby --update-kernel=ALL --args=initcall_blacklist=algif_aead_init
sudo reboot
F44 is safe as the kernel is greater than 6.18.22
The potential remedy doesn't work on RedHat and derivatives because the affected code is not a module there but statically compiled in.
I have checked all the servers (bookworm, bullseye) that I manage, and none of them have the algif_aead module loaded.
Seems not fatal to all non-patched systems.
Not having the module loaded doesn't mean you're not vulnerable, the kernel loads the module on-demand when it's needed. I tried the exploit on such a system, and it worked.
However, not having the module loaded does mean that in normal operation you don't need the module, so the proposed mitigation of disabling the module is safe in the sense that it won't disrupt anything.
I don't know what exactly can load this module but the servers are running for many weeks and I suppose that if something will load this module, it stays loaded until the next reboot.. no ?
I tried to rmmod on all servers and rmmod always returns `ERROR: Module algif_aead is not currently loaded`, that's why I think it's fine. Of course I take a look on https://security-tracker.debian.org/tracker/CVE-2026-31431 for the updates.
> I don't know what exactly can load this module
Well, for one thing, opening an AF_ALG socket, as the exploit does.
Ubuntu has patches out, tested before and after patching.
`initcall_blacklist` is a thing.
Was not disclosed to stagex, and I expect a lot of linux distros. Thankfully we were already on kernel 7.0 so not impacted
Related:
Copy Fail
https://news.ycombinator.com/item?id=47952181
huh somehow seeing people not using ai to work is like wow moment which i cherish a lot these days
Hey Xint Code / tylerni7 <https://news.ycombinator.com/threads?id=tylerni7>, maybe you should improve your disclosure process as well? Maybe make it mandatory for users of your tool?
they disclosed 30 days after the patch was merged in the thing they reported to.
its the same disclosure policy as google's project zero, and several other major players, so you should probably be trying to ping a lot more people
reporters should not be responsible for finding out and individually reporting to every downstream consumer. blame the kernel security team, who is in a much better position to coordinate notifications to individual distro security teams.
The security research community would run you out on a rail if you tried to take a successful research product and attach mandatory disclosure norms to it.