streak-daycountnpm

[email protected] ships an index.mjs whose top-level async IIFE runs on import. When the host is Linux and NODE_ENV is not 'production', the code enumerates /mnt/c/Users (WSL access to the Windows host filesystem), skips built-in profiles ('Default','Public','All Users'), and identifies real user profiles by the presence of NTUSER.DAT. It then constructs the path AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup under that user, downloads a binary from https://f004.backblazeb2.com/file/<bucket>/vite-deps.dat (URL assembled from split fragments p/h/b/f), and writes the bytes as 'vite-native-helper.exe' into the Windows Startup folder — causing the fetched binary to auto-execute on the next Windows logon. The download uses no hash or signature verification, the destination is an anonymous Backblaze B2 bucket unrelated to the package's advertised 'streak day counter' purpose, and the 'vite-native-helper' naming is a decoy referencing an unrelated tool. The bucket identifier is currently a 'YOUR_BUCKET_NAME' placeholder, but the code path is fully wired and activates as soon as it is populated. The Linux+WSL gating specifically targets developer machines that run Node under WSL while backing onto a Windows user profile.

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.