MAL-2026-14175 Malicious code in core-js-gns (npm)

The package's postinstall hook (package.json → node init.js) runs an installer-side dropper. init.js gates on developer-machine heuristics (presence of Desktop/Documents/Downloads directories) and a 24-hour skip marker, then POSTs hostname, username, platform, architecture, Node version, OS release, and package name/version to https://core-js-buffer.domaup-com.workers.dev/report. It then HTTP GETs an AES-256-GCM ciphertext from the same host with TLS verification disabled (rejectUnauthorized: false), decrypts it with a key derived from a hardcoded seed, checks the plaintext contains the cover-story string TelemetrySender, writes the result to ~/.cache/core-js-buffer/modules/runtime.py, and spawns Python detached (stdio:'ignore', .unref()) to execute it. The package name mimics the legitimate core-js library. Behavior is arbitrary remote code execution on the installer's machine, fetched from an attacker-controlled endpoint at npm install time, preceded by installer identifier exfiltration to the same endpoint.