MAL-2026-11149 Malicious code in streak-core-math (npm)

index.mjs executes a top-level async IIFE on import that fetches https://f004.backblazeb2.com/file/dp8hbvocjd2fpza/helper.zip, unzips it into %LOCALAPPDATA%/Microsoft/Windows/sysache, and writes vite-native-helper.vbs to the current user's Windows Startup folder. The VBS launcher uses WScript.Shell to run the unpacked RenameMe.exe on every user logon, giving the fetched binary persistent execution under the installer's account. All sensitive strings (the URL, process/fetch/child_process/fs identifiers, AppData/Startup paths, and the VBS body) are stored as hex literals in a _c table and decoded at runtime via Buffer.from(h,'hex').toString(), hiding the behavior from static inspection. Execution is gated to skip CI, NODE_ENV=production, and browser contexts, so it fires specifically on developer Windows machines. The filenames (vite-native-helper.vbs, sysache) and comments framing the block as a benign startup self-check are cover-story naming inconsistent with the package's advertised math-helper purpose.