MAL-2026-6143 Malicious code in node-vfs-polyfill (npm)

On install, postinstall.js executes automatically and exfiltrates host reconnaissance data to attacker-controlled subdomains on oastify.com (Burp Collaborator), a domain commonly used for out-of-band data exfiltration. The script imports http, https, os, and child_process; calls os.hostname() and execSync() to gather system identifiers; and POSTs the collected data — including hostname, username, and version fields — to hardcoded endpoints such as http://xxxxxxxxx.oastify.com and http://rni4z9qkil62r9dcwosokhtgo7u9i76w.oastify.com. The package name suggests a generic VFS polyfill but the postinstall does no polyfill work; its sole observable effect on npm install is system-info exfiltration. This matches the dependency-confusion / reconnaissance beacon pattern.

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.