Remote Code Execution Vulnerability in fabric-mod-utils Package
Summary
MAL-2026-17307: Malicious code in fabric-mod-utils (npm). Affects fabric-mod-utils versions 1.0.0. No fix is published. How to fix ↓
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Background
The fabric-mod-utils package is designed as a native asset loader bridge for Fabric mod environments, primarily used in gaming applications. It facilitates the integration of various assets within the Fabric modding framework. However, this package has been found to contain a serious vulnerability that allows for remote code execution during the installation process, posing significant risks to users.
Vulnerability Detail
The vulnerability originates from the package's post-install script, which executes 'node index.js'. This script performs an HTTPS GET request to a hardcoded malicious host (fabric-npm.gm-service.xyz) and executes the response using 'vm.runInContext'. This means that any code returned by the server is executed on the installer's machine, leading to potential unauthorized access, data theft, or system compromise. The obfuscation of the host and path variables adds an additional layer of deception, making it difficult for users to identify the malicious behavior.
How To Fix
This package is malicious. Remove it and rotate any credentials it could have accessed.
npm uninstall fabric-mod-utilsIf it arrived as a transitive dependency, remove the package that pulled it in, then reinstall.
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Workaround
As a temporary workaround, users can avoid installing the fabric-mod-utils package until a secure version is released. Additionally, consider using a package-lock.json file to monitor dependencies and prevent the installation of vulnerable packages. You can also use tools like Vulert to check for vulnerabilities in your application without needing to access the code directly.
Conclusion
The fabric-mod-utils package contains a critical vulnerability that allows for remote code execution, posing serious risks to users. It is essential to update the package to the latest version and utilize tools like Vulert for ongoing monitoring of vulnerabilities in your applications.
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FAQ
The vulnerability allows for remote code execution during the installation of the package, enabling attackers to run arbitrary code on the user's machine.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
If you have installed the vulnerable version of fabric-mod-utils, you should uninstall it immediately and update to the latest patched version.
While specific exploits may not be publicly documented, the nature of the vulnerability allows for significant risks, including unauthorized access and data compromise.
Vulert monitors and alerts users in real-time for open-source vulnerabilities in their software by analyzing the package-lock.json file, providing an easy way to stay informed.
