MAL-2026-12460 Malicious code in streak-count-core (npm)

[email protected]'s index.mjs executes a hex-obfuscated routine on module import (gated only by NODE_ENV!== 'production'). When it detects a WSL environment (process.platform === 'linux' with WSL_DISTRO_NAME set), it downloads https://f004.backblazeb2.com/file/dp8hbvocjd2fpza/helper.tar.gz, extracts it under the Windows host's user profile at /mnt/c/Users/<user>/AppData/Local/Microsoft/Windows/syscache, and writes env-setup.cmd into the Windows Start Menu Startup folder so the extracted RenameMe.exe auto-launches on every Windows login. All indicators — module names (fs/promises, path, child_process, https), env keys (NODE_ENV, WSL_DISTRO_NAME), the /mnt/c path, the Startup folder, the download URL, and tar arguments — are stored as hex strings in a _cfg object and reconstructed at runtime via Buffer.from(s,'hex').toString() before dynamic import() and spawn calls. The package's declared purpose (a streak counter library) does not require downloading and persistently installing a Windows executable on the host.

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.