We’re working with Cursor on this incident, but it wasn’t a compromise of Anthropic’s systems or employee laptops. A malicious actor used access to Cursor’s marketplace to publish a tampered copy of the Claude Code extension, which we didn’t build or publish. The versions on our official channels are not affected and this only impacts Cursor users.
All these security issues have made me want to build more of my own slimmed down tools. It would be great if there were better ways to use claude code with my own minimal harness and still have access to the pro plan.
Dworken from Anthropic here, that is correct: This only impacted the extension as it was hosted on the Cursor marketplace. It did not impact the official VS Code extension marketplace or OpenVSX. Users of Claude Code on VS Code are not impacted by this issue.
This is not directed at you personally but Anthropic (and everyone around this debacle) in general: please put some real effort behind planned crisis communications. The reporting on this has been atrocious and the comms coming from Anthropic have not really helped.
FWIW: the decision to publish an overriding version bump across all lanes was the correct one. It simplifies comms and helps to answer the first question every affected party has: "but what does this mean to ME?" - much easier to deal with the flood when you can start by sending back "are you running, or have you ever installed version Y?"
Time for technically accurate nuance comes shortly after, and in this case it has been lacking. Yes, you are dealing with confusing mix of various extension marketplaces. Explaining that to a questioning audience who do not have the necessary background information is non-trivial. Kevin's blog is pretty well known, but in this case the real updates are only coming in via a separate Mastodon thread (itself polluted by uninformed commenters) so the real, tangible and understandable details have still been missing.
Claude and its surrounding ecosystem are a huge, high-value supply chain compromise target. Cursor's extension being compromised is not your fault but it is still your problem.
Disclosure: done enough security incident comms in high-stakes environments with extremely demanding clients, operating under various regulations.
Don't worry, Anthropic (like the others) are experienced in shrugging off their problems: illegaly strip-mining training data, the massive environmental impact of their product, enabling bombing civilians and committing genocide -- if none of those stick, this itty bit of financial loss won't either.
Even more confusing is apparently Cursor Marketplace is OpenVSX + their own proxy to add extensions on top[0], so there are at least two possible cases:
1. The compromised version was present on OpenVSX itself, and Cursor Marketplace proxied to it
2. The compromised version was on Cursor's proxy, not OpenVSX itself
My guess is someone published an extension on vscode/cursor claiming to be Anthropic when it wasn't. Kind of like me publishing an app called Youtube on the app store, being accepted by Apple and having people download my malicious app called Youtube.
- Cursor (obviously) is not using MSFT vscode extensions library
- Cursor (apparently) is not using Open-VSX either!
- Cursor uses it's own "Cursor's marketplace" which is not public, no one knows what it is exactly, and looks like it is proxying open-vsx marketplace (?)
- THAT "Cursor's markeplace" is what was compromised today.
So. I would really really love someone from Cusro's team to step in and explain WTF just happened! (pardong the language)
Yes. Cursor marketplace is a mirror of Open VSX except they inject some plugins that are not in Open VSX for some reason. This works because Open VSX has basically no security. Which was already an issue.
Cursor was the first AI coding tool I used that had a "wow" factor and got me to switch over from typing out most of my code to having AI write most of it. But then when I used Claude Code for the first time, I never went back to Cursor.
I can see the value in a world where you still want to be a bit more hands-on with your code, but that didn't feel worth paying for anymore. Now if I want to be hands-on I actually prefer a minimalist editor with no AI features at all, while agents run in my terminal.
A lot of the most valuable SpaceX IP (at least to the big "advanced persistent threat" hackers) is probably related to military secrets, information to let you spy on/disable/control star shield/link, and so on. Not things we'd find out about as the general public.
I realized this earlier this year and dumped Cursor for just vscode along with 20x subs to Claude and OpenAI. Much cheaper and nothing of value was lost.
I'm still surprised people use CrowdStrike. I guess there are no real alternatives. I know companies are getting CrowdStrike alerts for this very issue, but it still just seems like a MASSIVE attack surface.
Back when I was in DevOps, the Linux Falcon Sensor was an absolutely disaster. They recompiled it for EVERY kernel release of every supported distribution (they had never heard of DPMS apparently), the service ran as root, it UPDATED ITS OWN BINARIES as root! It broke nearly ever Linux design philosophy.
I know newer version use eBPF and don't have the stupid kernel lock-in issue, but I still don't trust it.
If I had to guess it's that very few people use it for actual security guarantees and most use it just to be able to fill out the questionnaire or compliance box saying "we do this".
If Microsoft was any good the entire IT industry would collapse. Millions of high paying careers are built on decades of fixing the garbage that comes out of Redmond. Probably a trillion dollars worth of businesses selling software and support to companies running Microsoft would evaporate as soon as Microsoft doesn’t continue their current efforts.
I dont know a single person who uses this tool (but im sure there are some) our annual subs recently ran out, I hadnt used mine in 6 months, we did not renew.
Elon did the typical boomer tech guy thing when they interact with any slightly impressive AI tool.. Lose their fkn mind and spend tons of money on it. He just took it to another level..
Its like those tech boomers that got obsessed with openclaw and instantly started spending 20k a month on a thing that read their calender outloud to them.
Considering that the biggest and most successful play for SpaceXAI in the AI space has been "Sell compute to Anthropic" I also wouldn't say that all of the grok junk has been obviously successful, either.
I'm assuming there is no way to prevent this without Cursor improving their extension vetting? Seems like folks are confused in the comments here. To me, this is a 3rd party marketplace that lives outside of Anthropic's governance, is that correct?
Dworken from Anthropic here, yes this is correct. This is a third-party marketplace that we are not involved in owning, maintaining, deploying, or reviewing.
I'd suggest stop to use the word 'only' as it can be perceive wrongly here.
you can simply say Cursor users were affected. or exclusively.
just a tip from someone who worked tech support in cyber a long time. choice of words can really help change sentiments in these situations.
'only server xyz was affected' vs. 'server xyz was affected' or 'incident was isolated to server xyz' was often difference between shouting and crying customers or people understanding what was really meant.
I think the concern is that it could be seen as minimizing the harm done to those affected, but I personally think this is kind of a hypersensitive overcorrection :P
For locally installed Code / Code-fork extensions, there is not any concept of permissions (at least on Windows or MacOS (+ the 3rd party code-server running on Linux)), correct?
Dedicated user account does not work as eventually all your code and data will move under that.
I run it in an ephemeral container sandbox (https://github.com/ashishb/amazing-sandbox) which has access to the current working directory and it drastically limits the attack radius.
Dworken from Anthropic here, 2.1.313 was never published on OpenVSX, the VS Code marketplace, or on any of our official hosts. The malicious actor here had published a fake version of this extension on Cursor's marketplace. In order to disambiguate, we made sure our next update was 2.1.314.
Dworken from Anthropic here, 2.1.313 was never published on OpenVSX, the VS Code marketplace, or on any of our official hosts. The malicious actor here had published a fake version of this extension on Cursor's marketplace. In order to disambiguate, we made sure our next update was 2.1.314.
I think you’re being extremely negative towards Anthropic here. Basically the parent is saying “this is a problem at Cursor and not Anthropic” and you’re holding them accountable.
You’re literally saying that they should not have published on the Cursor marketplace but should have used OpenVSX because that would have been “reasonable”, but I think you’re being unreasonable here.
Since this morning I've seen a dozen "Anthropic hacked!!!" articles upvoted to the front page. There's really no use arguing with the mob. People will make up their own realities because they desperately want it to be true.
Doesn't HN have mods to correct article titles in cases like this? 7 hours in and I see "Backdoor in Claude Code for VS Code extension on the Cursor Marketplace"
Dworken from Anthropic here, I just want to be clear: OpenVSX was not impacted in this incident, the impacted system was only the Cursor marketplace that they host. We have confirmed that no Anthropic systems or employee devices are involved in this.
Dworken from Anthropic here, 2.1.313 was never published on OpenVSX, the VS Code marketplace, or on any of our official hosts. The malicious actor here had published a fake version of this extension on Cursor's marketplace. In order to disambiguate, we made sure our next update was 2.1.314.
Could be better to say "we're working with the Cursor team on this incident". Not your intent, but I initially understood that the Claude team was using Cursor-the-product (instead of Claude-the-product) to resolve the backdoors.
> Cursor said the extension was not developed by Anthropic and the maliciously modified extension was live on the marketplace from about 2:27 a.m. PT to 1:35 p.m. PT on Thursday
So is this or isn't this from Anthropic and how did this happen?
Dworken from Anthropic here, this did not involve a compromise of any Anthropic systems. A malicious actor used access to Cursor’s marketplace to publish a tampered extension targeting Cursor's users, we were not involved with building, publishing, or hosting this. The versions on our official channels including VS Code and OpenVSX are not affected and this only impacts Cursor users.
Anthropic only has an official extension for VS Code. Cursor is vs code fork and gave its own marketplace.
IIUC Anthropic does not publish extensions for Cursor. It’s basically, official Claude code extension “clone” not by Anthropic.
Ai summary in better words:
The Recent Malicious Build (v2.1.313): A tampered version of this extension (version 2.1.313) was uploaded to the Cursor extension marketplace. This specific, malicious build was not developed or authorized by Anthropic. Attackers effectively hijacked or spoofed the extension's legitimate identity within the Cursor/Open-VSX system to bundle an unauthorized SSH backdoor into the real Anthropic code.
And it is linked to here: https://code.claude.com/docs/en/vs-code (or, well, the URI doesn't tell us if it's using a proxied version or not, so it's complicated)
Obviously Anthropic didn't develop a malicious extension, but did they publish it? Did it sneak in, in a 3rd party library, or does someone have access to their marketplace account?
For what it’s worth, at one point one of our employees windows machines got infected, and the moment he did $something with Wordpress it intercepted the HTTP post and injected malware in there.
So that’s how these things can go, the employee’s machine may have been infected which was then used to inject this.
It was likely Anthropic, see my comment in other thread: https://news.ycombinator.com/reply?id=50302513&goto=item%3Fi... . Cursor
likely on purpose does bad reporting to minimize damage on Anthropic pre-IPO (as SpaceX and Anthropic have extensive business ties)
I don't think Spacex cares at all about Anthropics IPO just because they rent out their compute.
Big companies are not just 'Company' they are a lot of small teams doing their own things. They need to coordinate with other people for public announcements etc. and security team is probably also looking at it.
The person at the top refers to Anthropic as "Misanthropic". It seems unlikely that they're also intentionally lying about this to protect Anthropic's interests.
Wasn’t Elon Musk shouting a few days ago that neoclouds are going to crash, the money dried up and that SpaceX was the last company with the opportunity to raise more money?
They do have their own segment that is considered neocloud (data centers for compute), but they're mostly/fully used up with their own, and Anthropic's compute.
When he was talking about neoclouds, he was talking about the smaller guys who are getting bullied by vendors (mainly Nvidia) to buy as much hardware as possible (more than they want to). They paid more, for more, and needed to take on more debt, to end up (currently anyways) being well below capacity.
Over the next few years, unless growth keeps up (and probably accelerates), they'll need to sell, or restructure.
The buildouts by Microsoft, Google, Meta, OpenAI, and Anthropic are currently safe. The neoclouds that they've signed contracts with, are safe, but based on reports, that's roughly 60% of current capacity (it varies by report, but they're all under 75%).
True, but there are other people working at the companies that probably own stock in both their own company and some of the others...if you believe that this is the future, you'd be a fool to buy non-AI tech stocks, right?
My near-80 year old in-laws were talking about rogue agents and how a site called HuggingFace was hacked…
I didn’t need any more evidence. The media is fake and everything you see is designed to affect the stock price somewhere and if it can’t affect the stock price, you don’t see it.
But holy shit, they’re asking me if I saw the “rogue agents”.
Trillions of dollars are involved here to swing clueless people into being scared and also awed. It’s gross.
In all seriousness, there is nobody at Anthropic who can even give you that answer, because nobody there reads their pushed code anymore. Take a look at the previous Claude Code leaked codebases if you don't believe me, there is hundreds of files with 1000+ or more import statements at the top.
Any human would immediately tell you that it needs to be refactored from scratch. Their codebase also leaked that they're using review bots automatically instead of a human-in-the-loop review process.
If the docs are vibecoded too that would explain why there's a link to the compromised "not official" cursor version of the extension here https://code.claude.com/docs/en/vs-code which they supposedly aren't responsible for.
It sure seems like they've been vibecoding with everyone asleep at the wheel for a while.
I think it should be important to note that this affected the Claude Code extension on the Open VSX extension registry (and by extension, the Cursor marketplace). From what is currently known, the build on the official marketplace was/is clean.
EDIT: I am now actually unsure if this is the case. From what I can see, all of the write-ups mention the Cursor marketplace and Open VSX specifically, but make no explicit mention of the official Microsoft registry.
EDIT 2: The version that was compromised (2.1.313) seems to have never been published on the official Microsoft registry. As per the documentation [1], unpublished versions should still be discoverable:
> When you unpublish an extension, the Marketplace preserves the extension statistics. The extension remains publicly discoverable and available via an existing API.
Dworken from Anthropic here: This only impacted the extension as it was hosted on the Cursor marketplace. It did not impact the official VS Code extension marketplace or OpenVSX. Users of Claude Code on VS Code are not impacted by this issue.
You mean on the Microsoft VSCode marketplace? The version has been yanked from there as well, but that could just be a precaution and to avoid confusion about having the same version be simultaneously infected and not infected.
This very much illustrates the danger of just carelessly installing untrusted software on your machine. In this case it happens to be code from Anthropic, but it could have been almost anyone. I'll be very interested in see the explanation from Anthropic, because of all the extension developers they should have the best tools for finding issues like this. LLMs have proven pretty good at finding security issues, so did they simply not let their own AI tools vet the code before shipping it? Or was the extension infected later, because in that case every single extension on Open VSX could be at risk.
That is a really good question, because you almost can't do it. You could download the extension, diff it against the previous version and read all the code. Expecting people to do that it just a bit much. At some point we have to trust someone and in this case it will be interesting to see if it's the marketplace or Anthropic we couldn't trust.
> You could download the extension, diff it against the previous version and read all the code.
This would actually be an exceptionally good use-case for AI. You don't need a super-duper frontier model to download a bit of source-available code and check for suspicious signs, any cheap model would do well enough. Heck, it's effectively virus scanning, we've had that for decades.
Cursor explicitly claims "Before an extension is shown in search or served as a download, Cursor runs automated malware and supply-chain analysis using commercial security tooling. Extensions that fail review are blocked. Cursor also monitors extension-ecosystem threat intelligence and updates its blocklist over time."
However, the bad extension was live for ~11 hours.
The CTA flavor of the year for dev tools is cURLing some arbitrary install script and run it immediately which always sounded ridiculous to me. If instead that script first pipes into claude -p for a basic vulnerability scan before continuing, I would be delighted.
Most extensions run in vscodium-server, extensions run either as "Local Extensions" that run on the host and "Remote Extensions" that run on the guest. You can clearly see in the UI which ones run where.
I only have a single "Local Extension" and it is open-remote-ssh itself.
Of course anything you put into the container can be compromised, like git ssh keys or cloud provider keys/auth-tokens. But at least it keeps your PC from becoming a botnet and your browser credentials out of reach. If you have a Containerfile/Dockerfile with everything you need you can quickly wipe everything and re-create your dev environment from scratch (which I do every once in a while), wiping any malware you might have gotten in there.
When running inside a container you can do some nifty things like keeping root directories immutable. I have been meaning to make some user directories immutable in my container but just been too lazy to do it.
Three different marketplaces have been mentioned in this discussion:
1. The Cursor Marketplace (never heard of this one, it’s possibly a custom marketplace hard-wired into Cursor, which is architecturally a VS Code fork?)
2. The Visual Studio marketplace, hard-wired into VS Code
3. Open VSX
If I understand this thread correctly, then #1 and #3 had compromised versions, and nobody has made a statement yet about the status of #2.
Dworken from Anthropic here: This only impacted the extension as it was hosted on the Cursor marketplace. It did not impact the official VS Code extension marketplace or OpenVSX. Users of Claude Code on VS Code are not impacted by this issue.
I assumed they meant "also" as in "besides Cursor marketplace", which seems to be the highlight of the article. Although you raise a valid point and I've edited the parent comment.
> Yesterday, Anthropic were compromised and Cursor extension used by tens of millions of developers for Claude access was delivering a remote access trojan via an SSH reverse backdoor
That's a bit hyperbolic: someone released a version of the Claude Code VS Code extension with a backdoor on the Cursor marketplace:
> a maliciously modified version of Anthropic’s Claude Code extension was made available in the Cursor VS Code extension Marketplace
Cursor always used OpenVSX for VSCode extensions. There is separate "Cursor Marketplace" (https://cursor.com/marketplace) but it installs "Cursor Plugins" which are exclusively Cursor feature not related to VSCode, and Anthropic had never released a "Cursor Plugin"
This kind of thing is only going to get worse. People assume other devs are "like them" but state actors (think US, NK, RS, CN) are likely using AI at this point to run agents non-stop to break security by making dev tools or contributing to open source. Keep in mind that open source is the backbone of nearly all software being used - we're in for a rough ride if we don't treat all new things coming in as if they are potentially a nuclear bomb masquerading as a trojan horse.
So if this happened to OpenAI it would've been instantly auto-updated everywhere? VS Code has an "auto update delay" which I have configured to a week, but I just found out that (https://code.visualstudio.com/updates/v1_123):
> Note: This delay does not apply to extensions from trusted publishers such as Microsoft, GitHub, and OpenAI. These extensions continue to update immediately.
You can't even configure which publishers you "trust"...
If it defaulted to a week then it actually would have helped mitigated the spread. But it defaults to 2 hours, so there was a 9 hour window during prime US working hours yesterday when machines would have been auto-updating to the compromised extension.
Though Anthropic is claiming that the compromised package was published solely to Cursor’s marketplace, not not Microsoft’s.
I have this realization recently that everyone that uses Claude Code or Codex have basically been running RCE code on a daily basis (me included). So much for "be careful about running curl | bash!". That puts it into perspective what does security and privacy really mean? For all I know, these CLIs could have been secretly scraping my entire directory. Who's checking?
Don't forget: To make LLM useful you give it EVERYTHING it needs to know to be useful and if you don't use a certain provider with proper legal status, this is just gone.
We probably transfered more code/codebases and company secrets to random endpoints than ever before.
I only use agentic development tools in qemu VM that has no production
access or host shared folders, and the only secrets there are development.
I still have my Git ssh key there, but I never use ssh agent to load the keys.
The worst that agentic tools can do to me, is to install keylogger and compromise
my ssh key and password, but even then my deployment workflow includes creating release in Github,
which is not possible via ssh key only. I was very lucky to avoid the hack yesterday, as I use Claude installed via OpenVSX, but even if I installed the compromised version, the damage would be minimal.
I am doing similar with Debian 13 images in QEMU. Only access is to code specifically SSH in. On some, I am taking it a step further and my SSH key is not present at all on the bot. I add it as a git remote from my host into the VM and push and pull from there and then push to GitHub myself. So the agent has no path to GitHub either.
Wow, great notion about using git remote to transfer source from the agent host. I already use ssh into VM to transfer the files like designs for sharing, so going to adopt your approach right now :)
Then I just SSH in or use the vm gui and interact with the agent there. I like to keep it running in byobu so I can remote in more easily when I am on the laptop out and about.
Hell yeah that's the most sane and efficient personal dev sandboxing work flow I've heard and shows you know your stuff. Just basics but executed very well.
This was a compromise of the extension. The same kind of supply-chain attack could happen to literally any extension, package or other piece of software you install. Not excusing Anthropic letting this happen, but it doesn't have any bearing on the security and privacy of using Claude Code or Codex. Yes, you need to be careful about what they do. The fact that you might still get pwned via some other vector is irrelevant.
Can't their millions of agent swarms detect a malicious supply chain vector, sure it can happen to any company but not the one people are literally handing over their entire companies too.
Anthropic holds the SLA/MSA agreements not this bad actors what happens to your data is unknown if these become frequent and accepted. Given how much data is piped to Claude code via these services/extensions.
I'm just going to copy-paste my own comment from a few weeks ago because I feel like it is needing to be said more and more recently
---
I have, off and on, for years written diatribes about how if people in our industry want to run around with the "Engineer" moniker at some point they should start acting like it. That means respecting all aspects of what it means to be an Engineer and holding public well-being paramount is part of that. Licensure is part of that. Accountability and Responsibility is part of that.
I'm usually downvoted. The move fast and break things group seems to be blind (or willfully ignorant) to the harm that software systems can carry on a person's life. I don't know if its fear of regulation, or self-serving interests or some sort of disdain for the idea that we need to slow down and be more accountable to the public or what. At times the people I've engaged with lament on how they're capable but would be barred for lack of formal education or some such and its a distraction from the overall point: we need to be doing better and if we can't self-regulate then at some point we're going to be forced to act in a way that probably cuffs us more than necessary.
And yes, I understand how Software doesn't exactly fit into the mold of other engineering disciplines cleanly. But I think the idea that if we're going to have systems that can ruin a person's life in a second for a bug or oversight we need to start considering that accountability for those releasing software to the public matters. We lament about the difficulty of holding corporations to account for their harm, but it would be far more difficult for a company's negligence to hurt people if those turning the knobs were held to a higher standard.
I think that reckoning is coming soon. AI is going to create "an event" that we can't ignore and we're going to be pointing fingers in a lot of directions asking "how" we could prevent this from happening again. I'd argue "the event" has already occurred a few times over but we're purposely ignoring the severity of it to keep a diseased economy running roughshod. There's parallels with many historic events forcing regulation and the path forward won't be clean and easy.
I wouldn't hold regular engineers in such high regard. I know plenty of EEs, MEs and CEs that don't really give a f** about anything except a paycheck same as software developers.
I mostly agree, but I would like to mention that we are destroying our planet also because of the other fields of engineering :-).
Sure, software has a lot more malpractice ("let's ship barely-tested, unfinished stuff"), but let's not say that "the other engineers" are making the world a better place merely by "being real engineers".
Both is completely secure theoretically. You can read the output of the curl before you refetch and pipe it to bash. You can also look at the commands claude is executing.
I think the difference people were warned about is that the server can infer the client, so there would be a difference between reading it in your regular browser and curling. As the other commenter says, I'm not sure how the server would be able to tell what curl does with the response.
This is a cheap troll, but just in case someone is wondering: This extension likely never hit the standard workflow and/or repository. Most likely someone got the credentials and uploaded a locally modified version. No review system at anthropic has seen this version.
Why wouldn't their review system see a published extension and determine the very second it's published that it didn't match the results of a standard workflow?
I'm not sure where you see the flex. If someone gets hold of the token allowing the upload of your app to the store, it's completely irrelevant how good your internal code/review systems are. They've been completely bypassed and never triggered.
As an aside, it would be neat if publishing services like this had a sort of 2FA, eg the package manager had a hook endpoint where it sent the details of the next requested published version. Allowing the owners to validate.
Kinda like 2FA on the deployment itself, not just 2FA on the .. A. I guess 2FD heh.
Arguably, your security shouldn't stop at internal code review and should aim at protecting key distribution platforms credentials and assets that are pushed to your users.
Yeah, it shouldn't. But at that point it's not "Why didn't Claude detect the hack" but rather "Why isn't Claude running all processes at your company autonomously", which is a bit silly. We know it isn't and it's not at that level, because anthropic employs engineers.
> at that point it's not "Why didn't Claude detect the hack" but rather "Why isn't Claude running all processes at your company autonomously", which is a bit silly.
Would be nice to have some words from them understanding how they manage this, what went wrong, how they'll prevent this in the future. We don't have any RCA, maybe there is little to nothing to blame them.
Not sure they'd share your views on using Claude for security policy/coverage being silly.
It's legitimate question, it's the promise they are selling and doing IPO based off those promises.
Why don't they have their super intelligence looking thru it? If company selling those promises can't even do it for themselves, this is very suspicious
Having Claude examine all automatic software updates was considered as a policy, and it was found that it would stop 99.5% of software supply chain attacks. However the other 0.5% of the time it would install a backdoor itself.
I just built a retro OS for ESP32’s so that I can write BASIC programs and plop them on microcontrollers. My first ESP32 was a wrist watch. My second is a distraction free writer.
Cursor uses OpenVSX marketplace (https://open-vsx.org/), that all non-Microsoft forks of VSCode utilize
(official marketplace is only allowed in official proprietary VSCode release). It's not really related to Cursor/SpaceX in any way.
I suspect it's still Anthropic who were hacked, because they control OpenVSX
account with release privileges.
The affected Open VSX extension is owned by Anthropic employee Igor Kofman, but it is unclear whether his account or another part of the publishing process was compromised.
Yeah OpenVSX security is a joke, they also have dumb search algorithm which
allows for easy squatting of similar-looking extension names so they show up in search first when you look for official extensions. There were quite a few prominent hacks done that way. I think Microsoft likes OpenVSX situation because it allows them to claim
their proprietary VSCode marketplace to be more secure.
Vscode(ium) extensions are also pretty weak security wise in general. There's little guardrails on what an extension can do.
On publishing, I do see that the MS marketplace has much better typosquatting and rogue publisher protection. It's unclear to me how much better their SAST/scanning is than OpenVSX. Both have something, but both have been fooled many times, and recently.
There is no alternative really. Cursor was the market leader in LLM-assisted IDE experience before SpaceX acquisition, though Elon nerfed the product a lot in recent months. And there is still no
good alternative to it. Google tries to compete via Antigravity, but that also uses OpenVSX. I myself use Cursor and use Claude there installed via OpenVSX, and was not affected only thanks to my laziness (I saw upgrade button, but became distracted and did not click). I hope this situation will become a trigger to improve OpenVSX security.
Well for me, as developer on a modern stack, there is always some risk involved. If not from agentic tools, then the package registries are compromised left and right, so it all comes down to mitigating the risk. I use Claude, Codex and Cursor/SpaceX agents, and Cursor comes very convenient to have all three in a single interface. Also I still code manually especially when prototyping, so having an IDE helps with it as well. I knew about OpenVSX situation with the search, so when installing extensions I always did triple-checking to verify the extension being really submitted by upstream and not by squatter; but now given upgrades can also deliver a compromise I am thinking of developing an extension that will act in similar manner to pnpm minimum release age.
A lot of this is turning into “well other company said” but Anthropic claims OpenVSX is fine?[1] And that Cursor has their own market place. I’m confused.
> Dworken from Anthropic here, that is correct: This only impacted the extension as it was hosted on the Cursor marketplace. It did not impact the official VS Code extension marketplace or OpenVSX. Users of Claude Code on VS Code are not impacted by this issue.
Cursor has their own mirror of OpenVSX. Some reporting suggests the tampered files were on the Cursor mirror but not the main OpenVSX. (This is shown, among other things, by the Anysphere plugins available in the Cursor mirror but not in OpenVSX.)
Edit: It seems Cursor is claiming the tampered files were only in their mirror.
Sort of hoping it's Anthropic and their specific OpenVSX account credentials. As opposed to the worse case of an OpenVSX flaw that's broader. A ton of AI-enabled IDEs are VsCodium forks pointed at OpenVSX...Cursor, Anti Gravity, Kiro, Trae, Devin, etc.
Now I'm glad I've not opened VSCodium in a few weeks; I prefer using Claude as a separate application anyways, will have to remove the extensions.
No evidence, but I do feel like the problem is going to be OpenVSX and not Anthropic.
OpenVSX does have an option to use OIDC instead of a long lived token for publishing. I get the feeling a lot of people use the forever-good-unless-revoked token though.
The hacks and vluns are blending into a blur for me now -- why is Binance confirming Anthropic compromise while they have their own $6 Billion compromise to look at /s
Version 2.1.313 is missing from the official Claude Code GitHub repo's CHANGELOG[0]. There's also no tag[1] for 2.1.313[1], but 2.1.312[2], and 2.1.314[3] exist.
You’re likely right, but they also might’ve just pulled the version (number) everywhere to make it ‘clearer’ or out of ‘caution’.
Is there any industry standard about if a compromised version is distributed via one channel, the owner does or doesn’t drop/bump that same version on unaffected channels too?
I am starting to have a hard time who is responsible for what. I no longer know what's the relationship between companies/products like Anthropic, Cursor, SpaceXAI, Copilot, etc.
This has nothing to do with anthropic. One (or two) distribution channels were hacked. The hackers decided to distribute their malware through the claude extension, probably because it's popular.
A malicious version of Anthropic’s Claude Code VS Code extension, version 2.1.313, was published to the Open VSX registry on Oct. 30. According to ChainCatcher, security researcher Paul McCarty, known as 6mile, described the finding in a post on the OpenSource Malware blog. Researchers confirmed the analyzed Open VSX release was malicious and submitted a threat report about the same version on Microsoft’s VS Code Marketplace as a precaution.
Wasn't this an official build though? A signed updated version of a package released by the same developer as the one you've already installed, the supply chain was hacked.
I read a few month ago a comment from an Anthropic or OpenAI employee saying that the security problem of prompt injection was a solved problem at this point, as the frontier models where rejecting 98% of attacks.
It tells you all you need to know about how unserious these people are about computer security.
> I've recently talked to people at Anthropic who are very confident that they have effectively solved the prompt injection risks that cause lethal trifecta attacks with their latest models.
A 30 second search turned up this [1] from two days ago.
Prominent Anthropic employees keep claiming to have solved prompt injection [2] and quickly get proved wrong [3]. They've burned my goodwill on this front.
I'm not asking this in rhetoric; do you happen to have a link to this comment? I ask because a comment like that would be something of an insane thing for someone to say.
To me this very much sounds like an attacker got access to anthropic's cursor marketplace account and uploaded a backdoored package.
This reverse ssh shell was intentionally written by a malicious actor, not a security vulnerability.
It also sounds like only cursor marketplace is affected, not vscode proper.
I get the snark but to be fair, the company has been growing like crazy. That makes it really hard to keep track of everything happening when you grow your team by 5x over a relatively short period of time
Yes, food poisoning from restaurants happens constantly. There are recalls on physical products constantly. Doctors misdiagnose constantly. What point are you trying to make?
Not gp, but I think the point was that no one would defend those mistakes. The post gp is replying to is someone trying to excuse Anthropic for such a mistake. The expectation is that people should ask for consequences, not make excuses on behalf of the company.
If you completely change the statement, the meaning is different. What’s your point? No software company obeys by regulatory rules imposed in other industry
It always about “we solved the bottleneck in coding”. But the slowness was not about typing, or finding docs. It’s always about ensuring screwups don’t happen.
To be fair it’s not like screwups were not happening before, but if you move 100x faster and are 50x more secure than before you’re still 2x more exposed.
It affects their VSCode marketplace extension which in turn affects their cursor extension. Their official published version. This is plenty of reason to panic.
EDIT: This comment is probably nonsense, cf. the reply.
dang should change the title and/or merge this submission with the other one. [1] This is causing needless panic for a typosquatting-style "attack" unrelated to official Anthropic extensions.
> Claude Code for VS Code extension on the Cursor Marketplace
So Cursor is running its own extension repository? Or is this the official VS Code repository and the incident report just happens to focus on Cursor for some reason?
VS Code doesn't allow forks to use their marketplace, I think. At least with VSCodium, they don't. I think they even patch a workaround where you could download almost all extensions' .vsix files.
1. If only Cursor Marketplace version was compromised, how was it published in the first place?
2. If the Cursor Marketplace version was released from an "official Anthropic" account, whose to say OpenVSX and/or VSCode versions are not compromised?
The affected versions have been pulled down, so no one really knows. The way I see it, only Cursor has admitted to have been compromised.
Kind of surprised that Cursor doesn't do checksum verification for plugins. That would have stopped this completely. (Unless it does and this backdoor is more theoretical than anything else.)
Is this affecting only people using Cursor or all VS Code users? The article specifically mentions the Cursor marketplace. But the affected version is indeed missing on the official VS Code marketplace, was it compromised too?
Idea: why don't all the various app stores and plugin repos use LLMs to review all submissions for security? Certainly in the human powered age that was too big a task to take on, but now it seems doable.
Development must occur in an isolated VM, with no access to the publishing workflow. CI operations must happen in a separate VM or on the host system after scanning all files. Thus, even if the development tools are compromised (like this case), the impact is limited.
Still, it’s hardly a surprise that best practices are rarely followed with any consistency.
Maybe because the tools aren't of much help. This is all theory but when you want to do it it's custom solutions and duct tape.
There is too much friction when you try to isolate things. You have to do custom stuff then the company won't let you virtualize (can't install stuff...) or won't allow you to enroll the vm and will threaten you if you dev on an OS that is not enrolled.
Best you can get from state-of-the-art-frontier-top-it-company is an IDE with an exec sandbox leaking like an hourglass.
We still don’t know exactly what happened, but I publish software to public registries, and supply chain attacks scare the hell out of me. They also frustrate me, because most of the defenses aren't automatic and often really hard to get right. We're really failing as an industry to do better here.
This is why I started to move more and more into my tix.im environment. You can't trust anything anymore - I assume everything is compromised if not proven otherwise.
either the registry is compromised or someone at anthropic got compromised (or did it on purpose to steal crypto). the line in the cursor disclosure about the extension not being developed by anthropic is more confusing than clarifying. amateur hour for these massive corps
Reading the report alone:
"First, the payload makes sure ~/.ssh exists and appends an attacker-controlled Ed25519 public key to ~/.ssh/authorized_keys, setting permissions to 0700 on the directory and 0600 on the file."
A system where ~/.ssh/authorized_keys has not been modified might be a hint that this did not execute - the article does not mention self cleanup/reverting to previous status behavior by the malware. By default /var/log/auth.log is only of marginal value because outbound SSH connections are not logged by default.
More details from Kevin Beaumont. "Anthropic got compromised. Their Claude Code extension on Visual Studio Code and Cursor has malware in it, which creates a remote access Trojan to desktops. " https://cyberplace.social/@GossiTheDog/117528831681803563
My question here - does this effect those of us using the official vscode/vscode marketplace? It would seem to imply this was specific to cursor's marketplace but it would be good to know regardless
P(doom) crowd say Anthropic has not zero chance to destroy humanity.
What it is, the VS Code Extension Marketplace, including Cursor's, must be bigger.
Something very similar is true for ChatGPT on macOS. I was recently very surprised to learn that starting a "Work" conversation on my Mac would grant the agent session file system access which can later be used remotely, e.g. from a browser session logged into the same account on a different computer.
Given how many people likely share ChatGPT subscriptions, this seems highly problematic.
It's funny that's the point where people draw the line. But that basically every API based agent is doing RCE where commands are fetched from servers is perfectly fine.
Normal VS code doesn't even use Cursor Marketplace, right? The way this is reported lacks clarity. Do people using plain CS Code even use the Cursor Marketplace? Or am I missing something?
Has anyone managed to confirm the time that the backdoored version was released? None of my machines updated to it, I am wondering if it was saved by a combination of luck and
> This extension is not updated yet because new versions become eligible for automatic update 12 hours after they are published. It will become eligible in 2 hours.
My tin foil hat says MSFT stands the most to gain my this. https://open-vsx.org/ is where the attack took place, and that power’s all of the VSCode fork’s extensions needs.
Anthropic is a weird company. On the one hand they have this messianic thing about their super intelligence, on the other hand it is incapable of keeping their own house secure. But you should trust it.
It does. The compromised extension was published about 11 hours before Binance's coins went zoop, Binance blamed a compromised developer laptop, and OP pointed out that their hiring page explicitly notes developers will be using Cursor with Claude Code for "development efficiency".
VS Code extensions have always been terrible from a security perspective. This seems like it's a supply chain attack? Makes me think of Solar Winds from a few years ago.
It doesn't appear that the Claude Code harness itself was compromised, was it? or Cursor if you use Anthropic models via Cursor's API itself?
Lately I've been using a script that mounts my current working directory in a container and I put all my build tools in a Dockerfile. I also map the harness config (~/.config/opencode or whatever) to a named volume to minimize the chance a harness could grab other things off my host. I can't use it if I ask the LLMs for docker work since they need the docker socket and then all bets are off (it could just mount your root volume somewhere). I sure I could use a full QEMU VM or some other type of isolation for such devops tasks, but I haven't really looked into it yet. Guess I should.
You could also start whichever container it needs (the docker work) yourself and just have the two containers container with eachother (e.g. docker compose, without granting access to docker socket), provided that the docker work is static enough that this would work.
You could also look into user gVisor runtime for extra security.
If not, then I think you're right about full VM.
I've been eyeing Gondolin for a while for that, but haven't yet tried it.
I think right now AI is helping the attackers more than it's helping the defenders.
That part is probably obvious.
But in the long term, I suspect this will get worse.
Attackers will still need to think critically to be a few steps ahead of the defenders.
But the defenders will increasingly outsource their thinking to AI as they are incentived if not outright forced to dumb themselves down into interchangeable cogs.
This is why when I use AI, I still download from the browser and drag and drop the outputted files like a caveman. Sure, it's slower, but it keeps my mental model more up to date and has less security risks. I can even...like read the thing before I run it rather than giving a LLM access to my shell directly. Also anecdotally, it seems more token efficient for those who care about that.
Yes, but they normally have a 12-hour delay (it was 2 hours at the beginning of June and got extended sometime after that, maybe later in June) and require some human action to reload extensions or restart the editor before the new version runs.
I noticed that there was no update yesterday and wondered why. The daily updates are annoying in the base case.
Edited: This update was live for only 11 hours, so hopefully the default delay limited the blast radius, as it is meant to do.
Say you need an agent to do ssh to a set of servers on a regular basis so you kind of allow ssh. Can you configure just a set of IPs it may reach? Do you require some user interaction for ssh approvals?
In this case you could give it its own SSH key, and only allow that key to access what you want. I actually do that, it doesn't share my own SSH key. It also has its own Github account instead of getting access to mine.
For access to services, most allow tokens to be scoped to only allow the things you want.
Those sound good, but say in this case you had the compromised extension which had its own ssh key to an IP that wasn't yours.
I'm not sure how you easily prevent that connection without preventing the ones you need through sandboxing. Maybe a firewall/very specific network filtering in allowlist?
If the sole purpose of this hack was to steal cryptocurrency, a silver lining might be, as in many similar cases, that if you stay away from that particular dumpster fire you are probably okay. I mean there's still a reverse shell on your machine to fix, but at least nothing of value was lost.
now I kinda wanna shadow the usual SSH creds files with LLM read-only user, so it can rummage thru the repos all it wants but I need to do the push using my creds.
I suppose it's just the best ROI on using a complex attack vector or spending one or more zero days. But other types of targets may wreak havoc for bystanders that become collateral damage, idk trying to get specific private info on a target may expose data on millions, or anything increasing scope as to hide the real target, etc.
not just anthropic, my product that used antigravity is also leaked and copied by google, these close ai company will undoubtably steal your code, file and data.
strongly suggest put your valuable work on local llm.
This is embarrassing to Anthropic given here that they lack basic security procedures to prevent this and they have gotten themselves hacked to push malware.
Claude Code was already malware, but with this attack you cannot trust the vendor either.
In the next 2 weeks, no one should download / install / update anything as I predict at least one developer's key for a GitHub, NPM, Crates.io or any other CI or login was leaked and the attacker will target those services to propagate their trojan to more victims.
What I dont understand is why the hell do these extensions & clis need to update every damn day. clearly there's no new models everyday, what the actual f.
We’re working with Cursor on this incident, but it wasn’t a compromise of Anthropic’s systems or employee laptops. A malicious actor used access to Cursor’s marketplace to publish a tampered copy of the Claude Code extension, which we didn’t build or publish. The versions on our official channels are not affected and this only impacts Cursor users.
Let's say Anthropic has been impersonated and they are not at fault. I'd expect Cursor to provide information to them about this, and Anthropic being able to comment.
Btw, if you got any insights, you are more than welcome to share.
We’re working with Cursor on this incident, but it wasn’t a compromise of Anthropic’s systems or employee laptops. A malicious actor used access to Cursor’s marketplace to publish a tampered copy of the Claude Code extension, which we didn’t build or publish. The versions on our official channels are not affected and this only impacts Cursor users.
* "Cursor Editor" is a fork of VS Code
* The "Claude Code for VS Code" extension, v2.1.313, was compromised specifically on the Cursor Editor extension marketplace / distribution system
* The "Claude Code for VS Code" extension for regular VS Code on the official VS Code extension marketplace was not affected
Followup question: was a v2.1.313 also published on the official VS Code marketplace? If so, your statement is that that version was not compromised?
FWIW: the decision to publish an overriding version bump across all lanes was the correct one. It simplifies comms and helps to answer the first question every affected party has: "but what does this mean to ME?" - much easier to deal with the flood when you can start by sending back "are you running, or have you ever installed version Y?"
Time for technically accurate nuance comes shortly after, and in this case it has been lacking. Yes, you are dealing with confusing mix of various extension marketplaces. Explaining that to a questioning audience who do not have the necessary background information is non-trivial. Kevin's blog is pretty well known, but in this case the real updates are only coming in via a separate Mastodon thread (itself polluted by uninformed commenters) so the real, tangible and understandable details have still been missing.
Claude and its surrounding ecosystem are a huge, high-value supply chain compromise target. Cursor's extension being compromised is not your fault but it is still your problem.
Disclosure: done enough security incident comms in high-stakes environments with extremely demanding clients, operating under various regulations.
1. The compromised version was present on OpenVSX itself, and Cursor Marketplace proxied to it
2. The compromised version was on Cursor's proxy, not OpenVSX itself
[0] https://cursor.com/help/customization/extensions
here is the ddworken comment confirming https://news.ycombinator.com/item?id=50300683#50305148
- Cursor (obviously) is not using MSFT vscode extensions library - Cursor (apparently) is not using Open-VSX either! - Cursor uses it's own "Cursor's marketplace" which is not public, no one knows what it is exactly, and looks like it is proxying open-vsx marketplace (?) - THAT "Cursor's markeplace" is what was compromised today.
So. I would really really love someone from Cusro's team to step in and explain WTF just happened! (pardong the language)
They use a proxy in front of OpenVSX…purportedly for better security, the irony writes itself.
Which is exactly the opposite of what happened today.
What value is this VS fork actually adding given today's advanced harnesses? Surely whatever benefits it offers are not worth the risks going forward.
I can see the value in a world where you still want to be a bit more hands-on with your code, but that didn't feel worth paying for anymore. Now if I want to be hands-on I actually prefer a minimalist editor with no AI features at all, while agents run in my terminal.
A lot of the most valuable SpaceX IP (at least to the big "advanced persistent threat" hackers) is probably related to military secrets, information to let you spy on/disable/control star shield/link, and so on. Not things we'd find out about as the general public.
https://www.cnbc.com/2026/10/30/binance-hack-elon-musk-tesla...
People said the same thing about SolarWinds, Lenovo (Superfish), CrowdStrike... Nothing will happen.
My recollection is part of what uncovered it was that the malware broke WebSockets on Lenovo laptops.
I think higher end Lenovo laptops with cleaner windows images were not affected. And a lot of knowledgeable users wipe the OS anyway.
Back when I was in DevOps, the Linux Falcon Sensor was an absolutely disaster. They recompiled it for EVERY kernel release of every supported distribution (they had never heard of DPMS apparently), the service ran as root, it UPDATED ITS OWN BINARIES as root! It broke nearly ever Linux design philosophy.
I know newer version use eBPF and don't have the stupid kernel lock-in issue, but I still don't trust it.
Their Linux stuff has gotten much better but besides the (insanely huge) recent windows debacle I've found them to be a great product
"Do you use crowdstrike falcon?"
I mean, LastPass is still in business...
> I mean, LastPass is still in business...
I mean, Microsoft is still experiencing massive growth.
Elon did the typical boomer tech guy thing when they interact with any slightly impressive AI tool.. Lose their fkn mind and spend tons of money on it. He just took it to another level..
Its like those tech boomers that got obsessed with openclaw and instantly started spending 20k a month on a thing that read their calender outloud to them.
I wouldn't say it's obviously unsuccessful.
(you could have left out your little jab. it adds nothing to the conversation except flavoring your comment with smugness)
It's interesting what is considered acceptable and what isn't.
https://cursor.com/help/customization/extensions
you can simply say Cursor users were affected. or exclusively.
just a tip from someone who worked tech support in cyber a long time. choice of words can really help change sentiments in these situations.
'only server xyz was affected' vs. 'server xyz was affected' or 'incident was isolated to server xyz' was often difference between shouting and crying customers or people understanding what was really meant.
ive been sitting here for a few minutes trying to figure out what the 'wrong' perception here is.
why do people cry if you say "only"?
When you are invited to someone's living room, you don't get to access their bedroom.
The idea that Claude should have full data access to the home directory is wrong. And as an industry leader, Claude has set a bad precedence.
Be as close as AGI we are (/s), this issue from 2018 is still open:
https://github.com/microsoft/vscode/issues/52116
I don't know what we are doing.
I run it in an ephemeral container sandbox (https://github.com/ashishb/amazing-sandbox) which has access to the current working directory and it drastically limits the attack radius.
https://doublepulsar.com/anthropic-hacked-to-deliver-remote-...
Reads like Cursor's extension marketplace got compromised, hence how the OpenVSX and MS marketplaces can be unaffected.
https://www.npmjs.com/package/@anthropic-ai/claude-code?acti...
Is Cursor not an official channel for Claude?
You’re literally saying that they should not have published on the Cursor marketplace but should have used OpenVSX because that would have been “reasonable”, but I think you’re being unreasonable here.
As discussed here:
https://cyberplace.social/@GossiTheDog/117528831681803563
and as can be seen as there is no version 2.1.313 here: https://open-vsx.org/extension/Anthropic/claude-code/2.1.313
but there is https://open-vsx.org/extension/Anthropic/claude-code/2.1.314 https://open-vsx.org/extension/Anthropic/claude-code/2.1.312
Could be better to say "we're working with the Cursor team on this incident". Not your intent, but I initially understood that the Claude team was using Cursor-the-product (instead of Claude-the-product) to resolve the backdoors.
------
Check whether you are impacted
The malicious extension appends the attacker's public key, labeled svc-telemetry, to your SSH authorized keys. To check for it:
On macOS, run:
On Windows, run in PowerShell: ------[1] https://cursor.com/blog/claude-code-extension-security-notic...
> Cursor said the extension was not developed by Anthropic and the maliciously modified extension was live on the marketplace from about 2:27 a.m. PT to 1:35 p.m. PT on Thursday
So is this or isn't this from Anthropic and how did this happen?
an anthropic laptop? why are you sketpical?
IIUC Anthropic does not publish extensions for Cursor. It’s basically, official Claude code extension “clone” not by Anthropic.
Ai summary in better words: The Recent Malicious Build (v2.1.313): A tampered version of this extension (version 2.1.313) was uploaded to the Cursor extension marketplace. This specific, malicious build was not developed or authorized by Anthropic. Attackers effectively hijacked or spoofed the extension's legitimate identity within the Cursor/Open-VSX system to bundle an unauthorized SSH backdoor into the real Anthropic code.
That likely seems incorrect as I see Claude Code listed on open-vsx with:
* An "Anthropic" "Verified publisher" badge
* igorkofman listed who seems to be an Anthropic employee
* 63M downloads
* Reviews going back >1 year
https://open-vsx.org/extension/Anthropic/claude-code
So that’s how these things can go, the employee’s machine may have been infected which was then used to inject this.
Big companies are not just 'Company' they are a lot of small teams doing their own things. They need to coordinate with other people for public announcements etc. and security team is probably also looking at it.
Your conspiracy theory needs some work.
I think you’re giving Musk too much credit.
SpaceX will be re-valued on Anthropic's, or OpenAI's success, he, and his people are smart enough to understand this.
When he was talking about neoclouds, he was talking about the smaller guys who are getting bullied by vendors (mainly Nvidia) to buy as much hardware as possible (more than they want to). They paid more, for more, and needed to take on more debt, to end up (currently anyways) being well below capacity.
Over the next few years, unless growth keeps up (and probably accelerates), they'll need to sell, or restructure.
The buildouts by Microsoft, Google, Meta, OpenAI, and Anthropic are currently safe. The neoclouds that they've signed contracts with, are safe, but based on reports, that's roughly 60% of current capacity (it varies by report, but they're all under 75%).
SpaceX obviously has multiple sources of income, not just data center rents
So really, there's no way to say what was compromised and where.
This could have been avoided by having extensions signed by company doing them with their own keys and have them reviewed
https://cursor.com/help/customization/extensions
I didn’t need any more evidence. The media is fake and everything you see is designed to affect the stock price somewhere and if it can’t affect the stock price, you don’t see it.
But holy shit, they’re asking me if I saw the “rogue agents”.
Trillions of dollars are involved here to swing clueless people into being scared and also awed. It’s gross.
In all seriousness, there is nobody at Anthropic who can even give you that answer, because nobody there reads their pushed code anymore. Take a look at the previous Claude Code leaked codebases if you don't believe me, there is hundreds of files with 1000+ or more import statements at the top.
Any human would immediately tell you that it needs to be refactored from scratch. Their codebase also leaked that they're using review bots automatically instead of a human-in-the-loop review process.
[1] https://m.youtube.com/watch?v=3TNpOD6bov8
edit: downvoting me doesn't make it untrue, by the way. Check the leaked codebases, I dare you to provide evidence to the contrary.
It sure seems like they've been vibecoding with everyone asleep at the wheel for a while.
https://phorion.io/blog/offical-claude-code-vsx-compromise/
EDIT: I am now actually unsure if this is the case. From what I can see, all of the write-ups mention the Cursor marketplace and Open VSX specifically, but make no explicit mention of the official Microsoft registry.
EDIT 2: The version that was compromised (2.1.313) seems to have never been published on the official Microsoft registry. As per the documentation [1], unpublished versions should still be discoverable:
> When you unpublish an extension, the Marketplace preserves the extension statistics. The extension remains publicly discoverable and available via an existing API.
[1]: https://code.visualstudio.com/api/working-with-extensions/pu...
This very much illustrates the danger of just carelessly installing untrusted software on your machine. In this case it happens to be code from Anthropic, but it could have been almost anyone. I'll be very interested in see the explanation from Anthropic, because of all the extension developers they should have the best tools for finding issues like this. LLMs have proven pretty good at finding security issues, so did they simply not let their own AI tools vet the code before shipping it? Or was the extension infected later, because in that case every single extension on Open VSX could be at risk.
This would actually be an exceptionally good use-case for AI. You don't need a super-duper frontier model to download a bit of source-available code and check for suspicious signs, any cheap model would do well enough. Heck, it's effectively virus scanning, we've had that for decades.
However, the bad extension was live for ~11 hours.
https://github.com/jeanp413/open-remote-ssh
and run vscode-server inside a VM or container
I only have a single "Local Extension" and it is open-remote-ssh itself.
Of course anything you put into the container can be compromised, like git ssh keys or cloud provider keys/auth-tokens. But at least it keeps your PC from becoming a botnet and your browser credentials out of reach. If you have a Containerfile/Dockerfile with everything you need you can quickly wipe everything and re-create your dev environment from scratch (which I do every once in a while), wiping any malware you might have gotten in there.
When running inside a container you can do some nifty things like keeping root directories immutable. I have been meaning to make some user directories immutable in my container but just been too lazy to do it.
1. The Cursor Marketplace (never heard of this one, it’s possibly a custom marketplace hard-wired into Cursor, which is architecturally a VS Code fork?)
2. The Visual Studio marketplace, hard-wired into VS Code
3. Open VSX
If I understand this thread correctly, then #1 and #3 had compromised versions, and nobody has made a statement yet about the status of #2.
Edit: Cursor is apparently stating now that the tampered files were only on their mirror not OpenVSX.
That's a bit hyperbolic: someone released a version of the Claude Code VS Code extension with a backdoor on the Cursor marketplace:
> a maliciously modified version of Anthropic’s Claude Code extension was made available in the Cursor VS Code extension Marketplace
https://cursor.com/blog/claude-code-extension-security-notic...
There is more going on here. Cursor is covering for Anthropic because of the huge data center contract with SpaceX.
The Binance post should probably be the root link for this topic not this blog post - IMO
[0] https://www.binance.com/en/square/post/10-30-2026-claude-cod...
Edit: found an archived copy: https://archive.is/AND7z
Also worth noting that it doesn’t use Open VSX directly but uses a cursor hosted mirror at https://marketplace.cursorapi.com/open-vsx-mirror
> but it is unclear whether his account or another part of the publishing process was compromised.
God, people get so conspiratorial on HN when it comes to Ant
It's lucky that management doesn't want a 10x increase in output after laying off half the staff so we have a lot of time to vet deps! Oh no...
> Note: This delay does not apply to extensions from trusted publishers such as Microsoft, GitHub, and OpenAI. These extensions continue to update immediately.
You can't even configure which publishers you "trust"...
Though Anthropic is claiming that the compromised package was published solely to Cursor’s marketplace, not not Microsoft’s.
https://www.theverge.com/2023/9/15/23874798/microsoft-window...
What appears to be an official Binance account reporting it also:
https://www.binance.com/en/square/post/10-30-2026-claude-cod...
We probably transfered more code/codebases and company secrets to random endpoints than ever before.
Btw. you could setup a sandbox and limit access
``` host claudebox hostname 192.168.122.105 user developer IdentityFile ~/.ssh/id_rsa ```
``` host codexbox hostname 192.168.122.106 user developer IdentityFile ~/.ssh/id_rsa ```
I drop only my public key inside the VM. Then I set up the ~/Projects folder with the code the bot is working on any any authorized samples.
Then in my local on my host clone of the repository, I add another remote like
``` git remote add codexbox ssh://codexbox/home/developer/Projects/hello-world ```
Then git push codexbox.
Then I just SSH in or use the vm gui and interact with the agent there. I like to keep it running in byobu so I can remote in more easily when I am on the laptop out and about.
Anthropic holds the SLA/MSA agreements not this bad actors what happens to your data is unknown if these become frequent and accepted. Given how much data is piped to Claude code via these services/extensions.
Yeah I sympathize with people saying software developers should not be called engineers too.
I just think that the level of malpractice in software engineering is a lot higher than in other engineering fields, for some reasons.
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I have, off and on, for years written diatribes about how if people in our industry want to run around with the "Engineer" moniker at some point they should start acting like it. That means respecting all aspects of what it means to be an Engineer and holding public well-being paramount is part of that. Licensure is part of that. Accountability and Responsibility is part of that.
I'm usually downvoted. The move fast and break things group seems to be blind (or willfully ignorant) to the harm that software systems can carry on a person's life. I don't know if its fear of regulation, or self-serving interests or some sort of disdain for the idea that we need to slow down and be more accountable to the public or what. At times the people I've engaged with lament on how they're capable but would be barred for lack of formal education or some such and its a distraction from the overall point: we need to be doing better and if we can't self-regulate then at some point we're going to be forced to act in a way that probably cuffs us more than necessary.
And yes, I understand how Software doesn't exactly fit into the mold of other engineering disciplines cleanly. But I think the idea that if we're going to have systems that can ruin a person's life in a second for a bug or oversight we need to start considering that accountability for those releasing software to the public matters. We lament about the difficulty of holding corporations to account for their harm, but it would be far more difficult for a company's negligence to hurt people if those turning the knobs were held to a higher standard.
I think that reckoning is coming soon. AI is going to create "an event" that we can't ignore and we're going to be pointing fingers in a lot of directions asking "how" we could prevent this from happening again. I'd argue "the event" has already occurred a few times over but we're purposely ignoring the severity of it to keep a diseased economy running roughshod. There's parallels with many historic events forcing regulation and the path forward won't be clean and easy.
Sure, software has a lot more malpractice ("let's ship barely-tested, unfinished stuff"), but let's not say that "the other engineers" are making the world a better place merely by "being real engineers".
You always do that, right? ...right?
So you could be diligent and curl into a text file, see nothing is wrong, but then when you curl into bash, it runs something different.
Edit: thanks for the replies, that makes perfect sense
> No review system at anthropic has seen this
Weird flex
Kinda like 2FA on the deployment itself, not just 2FA on the .. A. I guess 2FD heh.
Would be nice to have some words from them understanding how they manage this, what went wrong, how they'll prevent this in the future. We don't have any RCA, maybe there is little to nothing to blame them.
Not sure they'd share your views on using Claude for security policy/coverage being silly.
Why don't they have their super intelligence looking thru it? If company selling those promises can't even do it for themselves, this is very suspicious
That wasn't a cheap troll. What they distribute and what Claude Code installs is on them. You're supposed to keep your channels clean and secure.
At a minimum they should monitor the larger marketplaces even if they're not in the chain.
(This is a joke, to be clear.)
Good that you said so, this is annoyingly plausible.
Sums up my feelings of the last few years nicely.
Its sort of like having a sysadmin constantly watching. Poking through logs pcaps & monitoring for unusual activities.
Also works with local models well enough.
It’s good fun building for retro-like machines.
Running NixOS helps.
Here’s a complete rundown of what happened—load-bearing parts first:
I suspect it's still Anthropic who were hacked, because they control OpenVSX account with release privileges.
edit:
Binance confirms my suspicions, via https://www.binance.com/en/square/post/10-30-2026-claude-cod...
This could have been avoided by having extensions signed by company doing them with keys and review
On publishing, I do see that the MS marketplace has much better typosquatting and rogue publisher protection. It's unclear to me how much better their SAST/scanning is than OpenVSX. Both have something, but both have been fooled many times, and recently.
Binance got a pretty expensive lesson if that was the cause for their recent hack
Why risk getting compromised like that?
> Dworken from Anthropic here, that is correct: This only impacted the extension as it was hosted on the Cursor marketplace. It did not impact the official VS Code extension marketplace or OpenVSX. Users of Claude Code on VS Code are not impacted by this issue.
1: https://news.ycombinator.com/item?id=50304585
Edit: It seems Cursor is claiming the tampered files were only in their mirror.
https://github.com/eclipse-openvsx/openvsx/wiki/Trusted-Publ...
Edit: Ah, guess it was not open-vsx, but a in-house Cursor marketplace. https://news.ycombinator.com/item?id=50304129
Anthropic's position is seemingly that it was "another part of the publishing process [that] was compromised"
Vibecoders are safu
Igor Kofman: "I do not write any code by myself anymore."
Turns out if you are not writing the code, then North Koreans might do it for you
Version 2.1.313 is missing from the official Claude Code GitHub repo's CHANGELOG[0]. There's also no tag[1] for 2.1.313[1], but 2.1.312[2], and 2.1.314[3] exist.
0: https://github.com/anthropics/claude-code/blob/main/CHANGELO...
1: https://github.com/anthropics/claude-code/releases/tag/v2.1....
2: https://github.com/anthropics/claude-code/releases/tag/v2.1....
3: https://github.com/anthropics/claude-code/releases/tag/v2.1....
Is there any industry standard about if a compromised version is distributed via one channel, the owner does or doesn’t drop/bump that same version on unaffected channels too?
Edit: the below was incorrect, left for posterity, the release can be deleted and then the tag as well.
Also, all their tags are immutable, and so can't just be deleted to hide things: https://docs.github.com/en/code-security/concepts/supply-cha...
Yes they can, they can remove the release and then remove the tag.
>If you delete the immutable release, you can delete the tag, but you cannot reuse the same tag name.
An official announcement from Anthropic would be nice!
Two out of the three links in the post still say exactly that.
That’s also what the majority of the comments here are saying, likely because they read the first two.
Is that your “nobody”?
I don't use Cursor or the VSCode extension, but know plenty in our organisation who use the latter. How worried should we be?
A malicious version of Anthropic’s Claude Code VS Code extension, version 2.1.313, was published to the Open VSX registry on Oct. 30. According to ChainCatcher, security researcher Paul McCarty, known as 6mile, described the finding in a post on the OpenSource Malware blog. Researchers confirmed the analyzed Open VSX release was malicious and submitted a threat report about the same version on Microsoft’s VS Code Marketplace as a precaution.
Wasn't this an official build though? A signed updated version of a package released by the same developer as the one you've already installed, the supply chain was hacked.
[1] https://news.ycombinator.com/item?id=50304129
Well probably yes but not at all relevant here... the problem wasn't the legitimate extension, it was cursor serving a fake malware one.
It tells you all you need to know about how unserious these people are about computer security.
> I've recently talked to people at Anthropic who are very confident that they have effectively solved the prompt injection risks that cause lethal trifecta attacks with their latest models.
> The open challenge is how to prove it!
https://news.ycombinator.com/item?id=50297369
Prominent Anthropic employees keep claiming to have solved prompt injection [2] and quickly get proved wrong [3]. They've burned my goodwill on this front.
[1] https://www.reddit.com/r/ClaudeCode/comments/1xhqvzn/opus_55...
[2] https://x.com/bcherny/status/2086520950259118464
[3] https://embracethered.com/blog/posts/2026/breaking-claude-co...
Or, is this FUD?
It also sounds like only cursor marketplace is affected, not vscode proper.
It may be the cause, but zero excuse.
How could Anthropic have known, they only claim to harbour superintelligence.
/s
It obviously doesn't take much to simply add 'just one more feature' that happens to undermine the original purpose of the application.
https://news.ycombinator.com/item?id=50302334 ???
"The Microsoft VSCode extension for Claude is NOT malicious"
"The Microsoft VSCode extension for Claude is NOT malicious"
https://opensourcemalware.com/blog/trojanized-claude-code-ex...
why are you spewing straight up lies?
"The Microsoft VSCode extension for Claude is NOT malicious"
dang should change the title and/or merge this submission with the other one. [1] This is causing needless panic for a typosquatting-style "attack" unrelated to official Anthropic extensions.
[1]: https://news.ycombinator.com/item?id=50301983
1. Open Cursor.
2. Press Ctrl + Shift + P.
3. Search for Preferences: Open User Settings (JSON).
4. Add:
{
So Cursor is running its own extension repository? Or is this the official VS Code repository and the incident report just happens to focus on Cursor for some reason?
2. If the Cursor Marketplace version was released from an "official Anthropic" account, whose to say OpenVSX and/or VSCode versions are not compromised?
The affected versions have been pulled down, so no one really knows. The way I see it, only Cursor has admitted to have been compromised.
Still, it’s hardly a surprise that best practices are rarely followed with any consistency.
There is too much friction when you try to isolate things. You have to do custom stuff then the company won't let you virtualize (can't install stuff...) or won't allow you to enroll the vm and will threaten you if you dev on an OS that is not enrolled.
Best you can get from state-of-the-art-frontier-top-it-company is an IDE with an exec sandbox leaking like an hourglass.
A system where ~/.ssh/authorized_keys has not been modified might be a hint that this did not execute - the article does not mention self cleanup/reverting to previous status behavior by the malware. By default /var/log/auth.log is only of marginal value because outbound SSH connections are not logged by default.
Given how many people likely share ChatGPT subscriptions, this seems highly problematic.
> This extension is not updated yet because new versions become eligible for automatic update 12 hours after they are published. It will become eligible in 2 hours.
As if this wasn't coordinated by a team directed by the government of North Korea.
It doesn't appear that the Claude Code harness itself was compromised, was it? or Cursor if you use Anthropic models via Cursor's API itself?
Lately I've been using a script that mounts my current working directory in a container and I put all my build tools in a Dockerfile. I also map the harness config (~/.config/opencode or whatever) to a named volume to minimize the chance a harness could grab other things off my host. I can't use it if I ask the LLMs for docker work since they need the docker socket and then all bets are off (it could just mount your root volume somewhere). I sure I could use a full QEMU VM or some other type of isolation for such devops tasks, but I haven't really looked into it yet. Guess I should.
You could also look into user gVisor runtime for extra security.
If not, then I think you're right about full VM.
I've been eyeing Gondolin for a while for that, but haven't yet tried it.
https://doublepulsar.com/anthropic-hacked-to-deliver-remote-...
That part is probably obvious.
But in the long term, I suspect this will get worse.
Attackers will still need to think critically to be a few steps ahead of the defenders.
But the defenders will increasingly outsource their thinking to AI as they are incentived if not outright forced to dumb themselves down into interchangeable cogs.
I noticed that there was no update yesterday and wondered why. The daily updates are annoying in the base case.
Edited: This update was live for only 11 hours, so hopefully the default delay limited the blast radius, as it is meant to do.
/s
Notable customers who run Claude Code and Cursor on laptops include Binance, amongst thousands of others.
Did the Claude Code plugin hack cause the Binance theft? The timing seems like an incredible coincidence.
You can try not installing malware like Claude Code or, if you absolutely must, doing it in a sandbox.
Say you need an agent to do ssh to a set of servers on a regular basis so you kind of allow ssh. Can you configure just a set of IPs it may reach? Do you require some user interaction for ssh approvals?
For access to services, most allow tokens to be scoped to only allow the things you want.
I've started developing with a separate user account to limit the blast radius but you still need to login to access repos and use AI features.
strongly suggest put your valuable work on local llm.
Claude Code was already malware, but with this attack you cannot trust the vendor either.
In the next 2 weeks, no one should download / install / update anything as I predict at least one developer's key for a GitHub, NPM, Crates.io or any other CI or login was leaked and the attacker will target those services to propagate their trojan to more victims.
This is fine.
[1] https://github.com/cookiengineer/check-claude-code-exfil
Hats off to the hackers.
We’re working with Cursor on this incident, but it wasn’t a compromise of Anthropic’s systems or employee laptops. A malicious actor used access to Cursor’s marketplace to publish a tampered copy of the Claude Code extension, which we didn’t build or publish. The versions on our official channels are not affected and this only impacts Cursor users.
How did they get access to this?
Btw, if you got any insights, you are more than welcome to share.