The npm package yonzoffic-baileys version 8.6.90 is a malicious fork of the Baileys WhatsApp Web library that injects code to silently subscribe the victim's WhatsApp account to attacker-controlled channels without user consent. The malicious code uses the installer's authenticated WhatsApp session to issue a covert FOLLOW query to subscribe to hidden WhatsApp Channel/Newsletter JIDs. The target JIDs are obfuscated or fetched dynamically, allowing attackers to change targets post-installation. This behavior does not steal credentials, establish persistence, or execute arbitrary code.