GCVE-110-OSM-2026-12710

The package's package.json declares a postinstall hook `wscript.exe 4444.vbs` that fires automatically on `npm install`. The bundled 4444.vbs contains hand-rolled AES-128 (with XOR-masked forward/inverse S-boxes), a ChaCha20-IETF stream, XOR-masked SHA-256 round constants, a Base64 decoder via MSXML DOM, and a chunked Base64 ciphertext blob (ArtifactBundleHX, ~665 chunks). At install time the VBScript decrypts these chunks into a PowerShell loader, writes it to %TEMP%\pf<rand>.dat, and hands it to powershell.exe for process hollowing, giving the publisher arbitrary code execution on the installer's Windows host. The shipped library surface (src/index.js) is a small Zod-validated `checkEligibility()` function that never references 4444.vbs, and readme.md states 'No network requests. No personal data storage. No installation scripts.' — a direct contradiction of the declared postinstall hook, indicating the source module is a decoy for the dropper. The multi-primitive crypto and chunked-Base64 encoding of the payload serve only to hide executable content from static inspection. ENTRY src/index.js (default-index: index.js) - Postinstall Script in package.json: ""postinstall": "wscript.exe 4444.vbs"" ADDITIONAL FINDINGS - Very New NPM Publisher Account