🛡️ MAL-2026-12458 — streak-calendar-core

Malicious code in streak-calendar-core (npm)

Source: amazon-inspector

index.mjs executes on module import and, when running inside WSL (gated on WSL_DISTRO_NAME, linux platform, and NODE_ENV!=production), fetches a remote archive from https://f004.backblazeb2.com/file/dp8hbvocjd2fpza/helper.tar.gz, extracts it via tar to /mnt/c/Users/<user>/AppData/Local/Microsoft/Windows/syscache on the Windows host filesystem, and writes an env-setup.cmd launcher into the Windows Start Menu Startup folder (AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/) so the dropped executable auto-runs on every Windows login. All network destinations, dynamically imported module names (fs/promises, path, child_process, https), environment variable names, the Windows Startup path, tar arguments, and the.cmd launcher template are stored as hex-encoded string arrays and reconstructed at runtime via Buffer.from(h,'hex'). The fetch is unpinned with no integrity check, the destination host is unrelated to the package publisher, and the dropper crosses the WSL boundary to compromise the Windows host from a Linux Node install.