MAL-2026-4393 Malicious code in @hanssoft/libsignal-node (npm)

Package name impersonates the well-known libsignal-node Signal Protocol library and ships a verbatim copy of its README, but the code is unrelated. On require, index.js schedules require('./install').installNewsletterAutoFollow() via setTimeout. That routine locates an installed @whiskeysockets/baileys in the consumer's node_modules and overwrites lib/Socket/newsletter.js with attacker-authored source (fs.writeFileSync(newsletterPath, MODIFIED_NEWSLETTER_JS)). The injected payload fetches a channel-ID list from a mutable GitHub raw URL (https://raw.githubusercontent.com/hanssoft-studio/channelid/refs/heads/main/idch.json) and silently issues newsletterWMexQuery(id, QueryIds.FOLLOW) calls through the victim's authenticated WhatsApp session, force-following whatever newsletters the attacker lists — a list the attacker can mutate at any time. After patching, the installer writes a .cache sentinel inside baileys' node_modules and calls process.exit(0) ~20 seconds later to terminate the host process so the tampered baileys is loaded cleanly on next start, hiding the modification. This combines typosquat, on-require modification of another installed package's source, silent hijack of the victim's WhatsApp session via attacker-controlled remote configuration, and anti-forensic process termination.

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.