MAL-2026-3670 Malicious code in 11j (npm)

Malicious package Published
Package
11j
Registry
npm

What is MAL-2026-3670?

MAL-2026-3670 is a malicious package in 11j, published on 12 May 2026.

Official description

the analysis identified unambiguous malicious behavior in log.js (the package main): an IIFE executes on require/import that monkey-patches console.log/warn/error to exfiltrate their first argument to a hardcoded Telegram bot endpoint with attacker-owned chat IDs and additionally PATCHes warn-intercepted data into an attacker-controlled Firebase RTDB. The module is further disguised with a large decoy DataTables employee dataset and a commented-out module.exports so require() returns {} while still installing the global console hooks. The combination of (a) load-time global side-effects, (b) two independent attacker-controlled exfiltration channels with hardcoded credentials/IDs, and (c) deliberate concealment via decoy data and suppressed exports constitutes a clear credential/data theft supply-chain attack with no plausible legitimate purpose. Package metadata ('11j', no description) provides no legitimate justification.

What should I do about MAL-2026-3670?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

Sources

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