streak-math-kitnpm

[email protected] is advertised as a math primitives library but its index.mjs top-level IIFE _bootstrap() runs on any import and drops a hex-embedded Windows PE named vite-native-helper.exe onto the host. Execution is gated by platform==='linux' && NODE_ENV!=='production' to target WSL developer environments. The code enumerates /mnt/c/Users/* to locate a Windows user profile (identified by the presence of AppData and NTUSER.DAT), then hex-decodes an approximately 500KB embedded binary with an MZ/PE header and writes it to that user's AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup directory, where Windows auto-executes it on the next logon. Path segments (AppData, Roaming, Startup subpath, NTUSER.DAT, the filename vite-native-helper.exe) are stored as hex-encoded string arrays and reassembled at runtime via Buffer.from(h,'hex') to hide the Windows-targeting behavior from casual source review. Source comments state the module has no network or filesystem side effects, contradicting the observed behavior. Result: any developer who imports this package from a WSL shell gains a persistent Windows executable that runs at every subsequent Windows logon.

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.