MAL-2026-4185 Malicious code in uolcs-host-uol-anuncios-fe (npm)

Package claims an internal-scope corporate name (uolcs-host-uol-anuncios-fe) on public npm, version-pinned to 99.99.99 — the canonical dependency-confusion shape designed to win resolution against an internal package of the same name in a target organization's CI. Both preinstall and postinstall hooks in package.json invoke node./callback.js, which reads os.hostname() and os.platform(), embeds them as a subdomain label (uolci-<hostname>-<platform>.d86r3dv5vn81lvohffp0131g8kdx9mz3c.oast.pro), and issues a DNS A lookup. The destination oast.pro is the interactsh out-of-band interaction listener; the DNS query itself is the exfiltration channel, capturing the installer's hostname and OS at the listener owned by whoever controls that token. The README's claim of authorized research is not verifiable from package contents and does not change the installer-side effect: any CI host or developer machine that resolves this name from public npm leaks identity to a third party on npm install.

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.

The OpenSSF Package Analysis project identified 'uolcs-host-uol-anuncios-fe' @ 99.99.99 (npm) as malicious.

It is considered malicious because:

• The package communicates with a domain associated with malicious activity.