react-fast-refresh-helpernpm

Package typosquats a React/Meta-branded name and falsely attributes authorship to 'Meta Open Source'. Its package.json declares a postinstall hook ("postinstall": "node install.js") that runs automatically on npm install. install.js fetches a Windows executable via https.get from an unpinned personal GitHub raw URL (raw.githubusercontent.com/Dunals/kl/main/keylogger.exe), writes it into the OS temp directory under the cover-story filename chrome_update.exe, sets mode 0755, and spawns it detached with stdio ignored. The remote source is a mutable third-party account, the fetched content is opaque and self-labeled 'keylogger', and execution occurs with no verification, hashing, or user interaction on default install.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.