xcvrenzcompany

GHSA-474r-6338-73gj

Malicious code in xcvrenzcompany (npm)

Details

**Severity:** Critical

**Affected versions:** `> 0`

This package is a fork of the Baileys WhatsApp Web library (npm) and belongs to the "PhantomSub" family described by OX Security in September 2026: the publisher injected code that, without the installer asking, uses the installer's own authenticated WhatsApp session to subscribe that account to WhatsApp Channels (newsletters) the publisher chose, by sending the WhatsApp `w:mex` FOLLOW query (query_id 7871414976211147) for each target channel JID.

`package/lib/Socket/newsletter.js` lines 62-99 define `AUTO_FOLLOW_JIDS`, three base64 strings decoded with `Buffer.from(..., "base64")`, and when the connection opens (line 97) schedule a FOLLOW query for each, 90 seconds apart (cited line 85: `await newsletterWMexQuery(jid, QueryIds.FOLLOW);`). Decoded JIDs: `120363400505489366@newsletter`, `120363430764800148@newsletter` and `120363387182851100@newsletter`. There is no opt-out and the behavior is not documented. The npm maintainer account (`xzv-expzc`) also publishes `prastzy`.

Line numbers refer to version 2.0.0; the same code is present in every published version listed under `affected`.

Static review of the published tarball(s) found no code that sends WhatsApp credentials or session keys off-host, no install-time payload (the only install hook is Baileys' stock Node.js version check in `engine-requirements.js`), and no persistence; the payload runs when an application creates a WhatsApp socket with the library. The harm is the covert use of the victim's account to inflate the publisher's channel subscribers.

SHA-256 of the published npm tarball(s): 1.0.0: `55a081ebf3ac419742490d3e1b2425ae56cfae323d1f8a64f4758515fbe83bda`; 2.0.0: `2e2befe5201e5a488f4e9253542630805500d210007760f09f9e9bbaac98934a`.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/d69382a194448ad0562ad4d9e4380c1c6a673841/osv/malicious/npm/xcvrenzcompany/MAL-2026-17452.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/d69382a194448ad0562ad4d9e4380c1c6a673841/osv/malicious/npm/xcvrenzcompany/MAL-2026-17452.json
- https://www.npmjs.com/package/xcvrenzcompany
- https://www.ox.security/blog/phantomsub-malicious-npm-campaign-secretly-adds-users-to-whatsapp-spam-channels
- https://github.com/advisories/GHSA-474r-6338-73gj

Compromised versions (1)

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.