MAL-2026-12466 Malicious code in streak-daykit (npm)

On import of the package's main entry, a top-level _bootstrap IIFE in index.mjs runs a Linux-gated routine that detects a WSL environment by probing /mnt/c, locates the active Windows user profile via NTUSER.DAT, fetches an executable from a hex-obfuscated URL that decodes to a backlazeb2.com host (a typosquat of Backblaze B2's backblazeb2.com), and writes the payload as vite-native-helper.exe into AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup on the host Windows account, establishing user-level autostart persistence. The remote URL, destination path, and dropped filename are all stored as split hex arrays joined at runtime and decoded via Buffer.from(h, 'hex').toString(), and surrounding comments frame the code as environment bootstrap and telemetry routing. No version pin, hash check, or publisher-matching source is present; the fetched binary is opaque attacker-controlled content executed on next Windows sign-in.

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.