The 'package-uploader' npm package at version 1.3.25 includes a postinstall script that runs 'install-hook.js'. This script contains a large base64-encoded binary payload that is XOR-decrypted and written as a temporary executable on Windows systems. The executable is launched detached, enabling execution of a hidden payload. After execution, a cleanup routine modifies package.json and package-lock.json to remove the dependency entry and deletes the installed module directory. If immediate deletion fails, it schedules a Windows task to remove the directory later. The package's stated purpose is a UI navbar library, but the main entry point only exports theme colors, serving as a decoy. The combination of obfuscated payload delivery, automatic execution, and anti-forensics cleanup confirms this as a supply-chain malware dropper. The campaign uses rotating package names, indicated by references to 'mailconfirmer' in cleanup code. Systems with this package installed should be considered fully compromised.

Any computer with 'package-uploader' version 1.3.25 installed is likely fully compromised. The malicious payload runs automatically on installation, potentially allowing attackers full control over the system. All secrets and keys stored on the compromised machine should be considered exposed and must be rotated from a secure environment. Removing the package alone does not guarantee removal of all malicious components due to the persistence mechanisms and cleanup obfuscation.

No official patch or fix is currently available for this malicious package version. The recommended mitigation is to immediately remove the 'package-uploader' package version 1.3.25 from all systems. Assume full compromise of affected systems and rotate all secrets and credentials from a secure, uncompromised environment. Monitor for any signs of persistence or additional malicious activity. Avoid installing or using this package or any variants with similar behavior.