MAL-2026-11036 Malicious code in streak-lib-math (npm)

On import, index.mjs executes an obfuscated async IIFE whose sensitive strings (process, fetch, fs/promises, target URL, path segments, payload filename) are stored as hex literals and reassembled at runtime. The code enumerates Windows user profiles reached from WSL via /mnt/c/Users, skipping default accounts (All Users, Default, Public, defaultuser0), fetches https://f004.backblazeb2.com/file/dp8hbvocjd2fpza/helper.dat, and writes the response bytes as vite-native-helper.exe into each targeted user's AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup directory. The binary then runs on every subsequent Windows login, providing persistent code execution on the developer host independent of Node or npm. The filename (vite-native-helper.exe) is a cover-story mimicking a Vite build helper; the package name suggests an unrelated math utility.

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.