Malicious code in @kxa/xbails (npm)

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: @kxa/xbails (npm), version(s): 0.0.5.

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Source: amazon-inspector (c79f4db658740bd17ea887f006f17b540a7d94fc79561df03035725e0986d590)

package.json for @kxa/[email protected] declares its libsignal dependency via an npm alias to an unofficial scope pinned to a mutable tag: "libsignal": "npm:@bellaxchuu/libsignal-node@latest". The official libsignal-node used by Baileys is published under WhiskeySockets; @bellaxchuu is an unrelated third-party scope. Because the alias uses the @latest tag with no version pin and no integrity constraint, every npm install of @kxa/xbails resolves whatever bytes that scope currently publishes and executes any lifecycle scripts (preinstall/install/postinstall) contained in them on the installer's host. The manifest itself is the install-time execution vector: the shipped code does not need to be malicious for arbitrary third-party code to run during install, and the resolved payload can change at any time without a new release of this package.

Source: ghsa-malware (1cc30c634ae2ff3ecb9a8a19343735301003bc57a51c63901090a3a60eb7c990)

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.