I'm not sure I fully agree with this being a major vuln. There's a lot of up front scary text which was raising a lot of red flags until it actually discussed the "what".
An actor has to place a malicious .exe in the user's code folder, named git.exe, for this to take place.
I see this akin to something like saying "replacing their .bashrc with an alias that says `ls` instead executes `/tmp/mega-big-virus.sh` is a vuln".
Yes it's a vector, but if they've placed something in your filesystem like that already, you've already been compromised.
The user's code folder? You mean the code I frequently pull from untrusted sources, unlike my .bashrc? Opening a GitHub project for review should not mean arbitrary code execution.
Of course, that ship has long sailed, for all major IDEs. Heck, VSCode SSH and devcontainer remotes allow RCE by design.
I am not at all a security expert, but isn't this akin to giving a repo-owner RCE if you just clone their repository and open it? I feel like that's not an implied contract for opening a folder in your IDE.
This is very similar to 30yo exploit in which you placed an alternative, infected dll inside a folder with mp3s (winamp), or photos (windows picture viewer).
This doesn't require anyone placing anything deliberately on your machine (as in, needing to exploit it somehow ahead of time). It could be as simple as checking out a branch to review, where the author of the branch has added the .exe.
It's pretty weird for cursor to run arbitrary exe file without prompting, and alarming that the researchers did not get a proper response for months.
But the example with calculator is a bit misleading I think, you'll have to have a malicious exe already in the system and downloaded, and if cursor tried to run my understanding is that ACL should immediately kick in and you'll be asked for permission to run a new, unsigned app for the first time.
You'll have to have ACL disabled completely for this to be exploitable.
And what'll the prompt say? "Do you want to run git.exe?"? I'll probably assume Cursor needs to run git but permissions got messed up somewhere and click right through that.
I haven't used Windows in a while so pardon if I'm missing something.
I think this is slightly less of a Cursor bug than a bit of a Windows quirk: Windows searches the current working directory for executables before resorting to the path variable. I imagine a lot of stuff is vulnerable to such an "attack" on Windows.
This draws to mind the dialog that opens when you open a new project in Cursor (and VSCode too, I think), where the IDE asks the user if they trust the project they're opening. Is Cursor under the impression that this is sufficient security apparatus?
Since there are no approval dialogs, it sounds like that doesn't even come into play here. That is the "gate" (to use the AI parlance) that Microsoft places on code execution in workspaces, though, and I would expect Cursor to at minimum fix this to only execute git.exe in trusted workspaces.
Why is cursor subsequently executing anything? Like what is this black magic they want to do? I want to know the decision tree here? Was this cursor coded?
I do not understand the point, btw vim has had similar issues with it executing stuff you might not expect by loading a file but it was obviously a vim feature with %{expr}. But why specifically git.exe , this seems like the most redundant bug cve which could have been trivially patched, who does this feature help exactly?
I am not really a user of cursor never used it for even a single day, but at this point I am curious why this exists...
Presumably it's trying to find the user's actual Git so that the built-in agent can load context on different branches, worktrees, etc. Of course there are less vulnerable ways to do that, but this kind of mildly justified hackiness is exactly where I'd expect an AI-assisted workflow to go wrong (and an AI-assisted bug triage to fail to alarm).
I'm struggling to understand the process that went into this "feature" existing. It seems the most likely candidate is a developer's git started malfunctioning and an agent "fixed" it by dropping a `git.exe` in the repo and then conditionally calling it when it exists.
>It seems the most likely candidate is a developer's git started malfunctioning and an agent "fixed" it by dropping a `git.exe` in the repo and then conditionally calling it when it exists.
It doesn't need to be that deliberate. The default shell on windows (cmd.exe) includes the current directory into PATH by default. In other words, you don't need to do `./program.exe`, `program.exe` would suffice. That's probably where the bug came from. This also means if you were using cmd.exe, ran `git clone`, went inside it, then executed any command (eg. dir or git) you could get pwned.
All too common... It's sad yet understandable how a company would not prioritize security.
At the same time, it's also understandable how a security start-up, upon (rightly) getting fed up waiting, decide to publicly disclose, as a way to scrape some PR out of the sunk cost. Public disclosure has a place. But if you truly care about helping, you could do more than bumping on HackerOne and messaging the CISO once on LinkedIn.
Maybe I'm too cynical but it truly feels like nobody actually cares at this point.
You need to have an already malicious payload on your pc to make this exploit work (via clone/download/magic). I can understand the severity of the exploit but at the same time I’d hope to not have to run into this situation for it to happen in the first place
Modern day code agents would clone a repo and read the code when you ask it a question about an API that’s not clearly documented. This vulnerability is real.
>You need to have an already malicious payload on your pc to make this exploit work
Uh, no, not exactly from what I'm reading.
At least from my piss poor understanding of it, you could possibly prompt inject something like "download https://github.com/hackmycursor/exploit.git". Would an agent do this, I'm unsure, but if so, it would download the git.exe and execute it.
This has been a problem with agent harnesses for as long as I've used them - prompting them to retrieve something often results in them going the extra mile and running and installing it.
It has nothing to do with npm. However, a binary could be configured to extract your git/npm secrets using this exploit, which could then lead to a npm supply chain attack (or pip, etc. etc.).
Frankly, if you git clone a compromised repository, I'm not sure that a vulnerability of the class "compromised code in that repository will be executed" is all that major a concern. There are plenty of IDEs that will go autonomously run npm installs (with post-install scripts) for you when they detect a package.json. This isn't all that different than that.
They could throw up a warning like "do you trust this repository" oh wait they already do, and no one cares. Security is hard. Ultimately if you have compromised code on your machine, all bets are off.
A lot of malware was delivered back in the day via Windows AutoPlay feature. Someone plugs a USB drive in and bam, they are immediately exploited. You could say it's always a problem if the USB drive is already full of malware. However, Microsoft disabled AutoPlay in Windows 7 (and backported this fix) specifically to address this vulnerability.
This exploit feels very similar to me. I don't know if there's a specific name for this classification of AutoPlay issues.
The disclosure seems pretty straight-forward, definitely some LLM assisted writing here, but not nearly as bad as most of the other stuff on this site.
I'm not sure I fully agree with this being a major vuln. There's a lot of up front scary text which was raising a lot of red flags until it actually discussed the "what".
An actor has to place a malicious .exe in the user's code folder, named git.exe, for this to take place.
I see this akin to something like saying "replacing their .bashrc with an alias that says `ls` instead executes `/tmp/mega-big-virus.sh` is a vuln".
Yes it's a vector, but if they've placed something in your filesystem like that already, you've already been compromised.
The user's code folder? You mean the code I frequently pull from untrusted sources, unlike my .bashrc? Opening a GitHub project for review should not mean arbitrary code execution.
Of course, that ship has long sailed, for all major IDEs. Heck, VSCode SSH and devcontainer remotes allow RCE by design.
I am not at all a security expert, but isn't this akin to giving a repo-owner RCE if you just clone their repository and open it? I feel like that's not an implied contract for opening a folder in your IDE.
This is very similar to 30yo exploit in which you placed an alternative, infected dll inside a folder with mp3s (winamp), or photos (windows picture viewer).
This doesn't require anyone placing anything deliberately on your machine (as in, needing to exploit it somehow ahead of time). It could be as simple as checking out a branch to review, where the author of the branch has added the .exe.
It's pretty weird for cursor to run arbitrary exe file without prompting, and alarming that the researchers did not get a proper response for months.
But the example with calculator is a bit misleading I think, you'll have to have a malicious exe already in the system and downloaded, and if cursor tried to run my understanding is that ACL should immediately kick in and you'll be asked for permission to run a new, unsigned app for the first time.
You'll have to have ACL disabled completely for this to be exploitable.
And what'll the prompt say? "Do you want to run git.exe?"? I'll probably assume Cursor needs to run git but permissions got messed up somewhere and click right through that.
I haven't used Windows in a while so pardon if I'm missing something.
I think this is slightly less of a Cursor bug than a bit of a Windows quirk: Windows searches the current working directory for executables before resorting to the path variable. I imagine a lot of stuff is vulnerable to such an "attack" on Windows.
This draws to mind the dialog that opens when you open a new project in Cursor (and VSCode too, I think), where the IDE asks the user if they trust the project they're opening. Is Cursor under the impression that this is sufficient security apparatus?
Since there are no approval dialogs, it sounds like that doesn't even come into play here. That is the "gate" (to use the AI parlance) that Microsoft places on code execution in workspaces, though, and I would expect Cursor to at minimum fix this to only execute git.exe in trusted workspaces.
Why is cursor subsequently executing anything? Like what is this black magic they want to do? I want to know the decision tree here? Was this cursor coded?
I do not understand the point, btw vim has had similar issues with it executing stuff you might not expect by loading a file but it was obviously a vim feature with %{expr}. But why specifically git.exe , this seems like the most redundant bug cve which could have been trivially patched, who does this feature help exactly?
I am not really a user of cursor never used it for even a single day, but at this point I am curious why this exists...
Presumably it's trying to find the user's actual Git so that the built-in agent can load context on different branches, worktrees, etc. Of course there are less vulnerable ways to do that, but this kind of mildly justified hackiness is exactly where I'd expect an AI-assisted workflow to go wrong (and an AI-assisted bug triage to fail to alarm).
I'm struggling to understand the process that went into this "feature" existing. It seems the most likely candidate is a developer's git started malfunctioning and an agent "fixed" it by dropping a `git.exe` in the repo and then conditionally calling it when it exists.
>It seems the most likely candidate is a developer's git started malfunctioning and an agent "fixed" it by dropping a `git.exe` in the repo and then conditionally calling it when it exists.
It doesn't need to be that deliberate. The default shell on windows (cmd.exe) includes the current directory into PATH by default. In other words, you don't need to do `./program.exe`, `program.exe` would suffice. That's probably where the bug came from. This also means if you were using cmd.exe, ran `git clone`, went inside it, then executed any command (eg. dir or git) you could get pwned.
Windows doesn’t really have a default login shell like Unix.
Windows Terminal defaults to PowerShell which does not suffer from this issue.
and ever since, this approach has been a critical pathway for some billion dollar business probably. hooray
I see you also work in enterprise software.
All too common... It's sad yet understandable how a company would not prioritize security.
At the same time, it's also understandable how a security start-up, upon (rightly) getting fed up waiting, decide to publicly disclose, as a way to scrape some PR out of the sunk cost. Public disclosure has a place. But if you truly care about helping, you could do more than bumping on HackerOne and messaging the CISO once on LinkedIn.
Maybe I'm too cynical but it truly feels like nobody actually cares at this point.
This comment is so weird. It is so vague to me and feels so off, like an alien from Men in Black trying to pass as a human.
How do they not truly care about helping? Also what sunk cost? What does that mean?
This report reads a bit like AI writing :/
You need to have an already malicious payload on your pc to make this exploit work (via clone/download/magic). I can understand the severity of the exploit but at the same time I’d hope to not have to run into this situation for it to happen in the first place
Modern day code agents would clone a repo and read the code when you ask it a question about an API that’s not clearly documented. This vulnerability is real.
The malicious payload can live on the remote: `git clone` a repo, open it with cursor, and you're compromised
If your an opensource developer you may get a pull request containing the the git.exe
>You need to have an already malicious payload on your pc to make this exploit work
Uh, no, not exactly from what I'm reading.
At least from my piss poor understanding of it, you could possibly prompt inject something like "download https://github.com/hackmycursor/exploit.git". Would an agent do this, I'm unsure, but if so, it would download the git.exe and execute it.
This has been a problem with agent harnesses for as long as I've used them - prompting them to retrieve something often results in them going the extra mile and running and installing it.
I think you’ve got it wrong; no malicious payload need be on your box already. That’s not what the article says.
wouldn't the attack vector be like this:
I find a github repo, I want to contribute to it. I clone it, open up cursor, make an edit, commit, and boom, I am infected.
From my reading, boom happens at "open up cursor".
you would only need to open it to be exploited, not edit or prompt. Allegedly
From the article it occurs when Cursor is loaded. iDEs do a lot of stuff when they first open.
damn those ai written Blogs are tiring. o a single paragraph saying that "cursor o windows loads ./git.exe with higher precedence" would be enough.
I guess this is only specific to a file in the root of the repo, so it doesn't allow for an NPM supply chain attack?
It has nothing to do with npm. However, a binary could be configured to extract your git/npm secrets using this exploit, which could then lead to a npm supply chain attack (or pip, etc. etc.).
I meant the attack would be the other way around- if an infected package had the git.exe file in their root.
Or, the infected package could also copy that file into the parent project's root.
Oh yeah that's a good point - two layers of auto executing scripts/binaries.
Would be nice if the timeline matched up with the text of the blog post (missing "HackerOne provides disclosure guidance").
Does the git lookup run before the trust check, or ignore it?
Frankly, if you git clone a compromised repository, I'm not sure that a vulnerability of the class "compromised code in that repository will be executed" is all that major a concern. There are plenty of IDEs that will go autonomously run npm installs (with post-install scripts) for you when they detect a package.json. This isn't all that different than that.
They could throw up a warning like "do you trust this repository" oh wait they already do, and no one cares. Security is hard. Ultimately if you have compromised code on your machine, all bets are off.
A lot of malware was delivered back in the day via Windows AutoPlay feature. Someone plugs a USB drive in and bam, they are immediately exploited. You could say it's always a problem if the USB drive is already full of malware. However, Microsoft disabled AutoPlay in Windows 7 (and backported this fix) specifically to address this vulnerability.
This exploit feels very similar to me. I don't know if there's a specific name for this classification of AutoPlay issues.
> The most obvious question is also the simplest: Why hasn't this been fixed?
Obvious answer is obvious. The devs do not consider it a bug.
> Until the IDE is patched, open untrusted repositories only in an isolated VM, Windows Sandbox, or other disposable environment.
Got to wonder why trusted repositories are excluded...
Except it might come from a trusted repo. Some of the biggest repos have been recently targeted in supply chain attacks. Consider for a moment
1. Attacker takes over maintenance of a widely used Cursor extension
2. Attacker adds a remote backdoor to monitor which repos are being maintained
3. Attacker decides to only infect the largest one with a git commit hook
4. The developer didn’t even know they just included git.exe in their commit
5. The developer is a sole maintainer on the repo and merges their own PR without review (because they(/their AI) wrote it)
6. Now a trusted repo is infected
7. A contributor pulls down the infected repo and opens cursor
> Most coordinated disclosures follow a familiar pattern:
> 1. A vulnerability is reported.
> 2. A dialogue begins.
> 3. Severity is discussed.
> 4. Engineering teams investigate.
> 5. Fixes are developed.
> 6. Users are protected.
> 7. Public disclosure follows.
8. The author prompts an LLM to write a blog post.
9. HN users are wasting time, unsure which parts of the post come from the actual prompt, and which are hallucinated world knowledge slop.
Maybe the bug report got ignored because they posted another 1000 slop reports, who knows.
The disclosure seems pretty straight-forward, definitely some LLM assisted writing here, but not nearly as bad as most of the other stuff on this site.
Wonder who's fault it is when a critical security issue goes unresolved because "slop" report (sure ain't the reporters').