MAL-2026-10981 Malicious code in streak-calendar (npm)

index.mjs contains a top-level async IIFE that fires when the module is imported. When running on Linux with NODE_ENV!= 'production' and a WSL-style /mnt/c mount present, it enumerates Windows user profiles under /mnt/c/Users, downloads an opaque binary from https://f004.backblazeb2.com/file/dp8hbvocjd2fpza/vite-dep.dat, and writes it as vite-native-helper.exe into the selected user's AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup folder, achieving persistent code execution on the Windows host at next login. The destination URL is assembled from split string fragments (p/h/b/f variables), the trigger is gated to non-production Linux hosts with a WSL mount, and the file names (vite-dep.dat, vite-native-helper.exe) use a Vite-themed cover story unrelated to the package's advertised purpose. The Backblaze B2 bucket is anonymous and not associated with the package publisher, and there is no hash or signature verification on the fetched binary.

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.