MAL-2026-17522 Malicious code in studiocode_eligibility (npm)

package.json declares a postinstall hook wscript.exe 4444.vbs that automatically executes a 765KB VBScript shipped in the tarball on Windows installers. The VBS contains multi-layer obfuscation (XOR-decoded AES S-boxes, SHA-256 constants, a ChaCha20 stream layer, and a large Base64 'ArtifactBundleHX' blob) that decrypts a PowerShell loader, writes it to %TEMP%\pf#####.dat, and invokes it via powershell.exe using process-hollowing-style techniques. The library source (src/index.js) is a small Zod-based email-domain eligibility checker that is unrelated to the VBS payload and serves as cover. The README explicitly claims 'Checks run locally, without network requests' and 'There are no installation scripts', directly contradicting the declared postinstall hook and shipped dropper. Running npm install studiocode_eligibility on Windows grants the package author arbitrary code execution on the installer's machine.