MAL-2026-5692 Malicious code in ecto-win-flag-q2m7 (npm)

On npm install, postinstall.js executes a harvest-and-exfiltrate chain against the installer's machine. It reads files under /app, /root, and /flag.txt, shells out via execFileSync('/bin/sh', ['-c',...]) to recursively grep the filesystem for HTB{...} flag patterns and collect git history, gathers host identifiers (uid, cwd, hostname), and transmits the collected data via HTTP PUT to a hardcoded attacker endpoint at http://154.57.164.82:31250/api/modules/ECT-*. The script includes sandbox-evasion gating that exits cleanly when cwd contains /tmp/npm-safe or /tmp/pkg, or when hostname matches nijin, hetzner, or ec2.internal — ensuring the malicious path only fires on real installer machines. The combination of unconditional filesystem read, hardcoded non-registry IP destination, and scanner-evasion logic is an unambiguous supply-chain attack.

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.