MAL-2026-4519

Dashboard / Malicious Package / MAL-2026-4519

MAL-2026-4519

Summary: Malicious code in chromestaff-baileys (npm)

Details: This package is part of a large family (100+ identified as of September 2026) of near-identical forks of the Baileys WhatsApp Web library that inject a covert channel-subscription action into the WhatsApp socket layer. On connect, the injected code issues an authenticated `w:mex` FOLLOW query (query_id 7871414976211147) against one or more attacker-chosen WhatsApp Channel/Newsletter JIDs, using the installer's own authenticated WhatsApp session -- silently subscribing the victim's account to channels it never asked to join. The target JID(s) are hidden from casual source review via one of several obfuscation techniques observed across the family: a plain string literal, base64 encoding, base64+XOR, or a char-code array reconstructed at runtime. Some variants instead fetch a mutable, attacker-controlled remote JSON/JS list of target JIDs from GitHub or another host at runtime, letting the target list change after installation without a new npm publish. Every sample in the family shares the same underlying mechanism (a wrapped/patched socket-connect routine that fires the FOLLOW query some seconds after connect), even though the package name, JID value(s), and obfuscation/delivery method differ per fork. The malicious action abuses the installer's own authenticated WhatsApp session to gain reach and subscribers for attacker-controlled channels; it does not exfiltrate credentials, establish persistence, or execute arbitrary remote code. Affected package: chromestaff-baileys (npm), version(s): 1.2.7. Source: amazon-inspector (4d5fad12014025f37f607a61051a445262f37bcee6682850dfd77cc0dcb0b486) chromestaff-baileys is a fork of the Baileys WhatsApp library that, on every successful WhatsApp connection, silently forces the connected user's WhatsApp account to follow a hardcoded author-controlled newsletter (`120363418582531215@newsletter`). In `lib/Socket/socket.js` line 541 a constant `varebotxbased = '120363418582531215@newsletter'` is defined, and around line 617 a function `autoSubscribeToDefaultNewsletterIfRequired()` is invoked from the `ws.on('CB:success',...)` handler, calling `followNewsletterWMex(varebotxbased, timeoutMs)`. The action is undocumented, gated by a `creds.basedbysam` flag so it fires once per account with up to 3 retries, and hidden behind opaque identifiers. Any application built on this fork conscripts its end users' WhatsApp identities into following the author's channel without consent. The package metadata reinforces the deception: name `chromestaff-baileys` and description `baileys by filo e giuse` impersonate the legitimate `@whiskeysockets/baileys` library, while the homepage is a placeholder invalid URL `git+https://github.com/precisione.git`. This is a silent-relay pattern: normal use of the advertised Baileys API silently performs an action benefiting the author against the caller's WhatsApp account.

References: https://www.npmjs.com/package/chromestaff-baileys/v/1.1.3, https://www.ox.security/blog/phantomsub-malicious-npm-campaign-secretly-adds-users-to-whatsapp-spam-channels/