MAL-2026-5506 Malicious code in argoncrypt (npm)

On require, index.js spawns a detached, unref'd Node child running lib/initializeCaller.js. That file decodes a base64-disguised URL (https://tomato-brunhilda-40.tiiny.site/index.json), fetches the response, and invokes it via new Function.constructor('require', response)(require) — granting the fetched code full Node capability with access to require. The destination is an anonymous free static-site host with no pinning, hash check, or signature verification; the fetch is retried up to 5 times. The C2 URL and HTTP header values are hidden as base64 strings stored under fake process.env.DEV_* defaults to evade casual review and string-search. The package additionally masquerades as a pino logger transport (exports module.exports.pino, ships a smoke:pino script, references a non-existent ./pino module) despite a name unrelated to logging — a cover story for the dropper. Any developer or build system that installs and imports argoncrypt will silently execute attacker-controlled code with full host privileges.

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.