mfakitnpm
Advisory published Updated
mfakit is a confirmed malicious npm package (MAL-2026-15558) that steals credentials and exfiltrates sensitive data (malicious version 1.4.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in mfakit (npm)
What this malware does
The package advertises itself as a lightweight Discord MFA library, but require() of its main entry loads lib/cache.js which schedules a setImmediate handler that runs on Windows (guarded by process.env.SystemRoot). The handler XOR-decodes hidden hex constants against a base64 salt to reconstruct a fetch URL (https://limbomail.com/api/attachment/r_Ea6rT_kGfT.o7nh0aBVvDQWmOG47NPBQ3pUjd_uHeiw) and OS-command tokens (child_process, spawn, execSync, wscript.exe, node.exe, attrib +h +s). It downloads a script to %APPDATA%\Microsoft\Windows\WinSxS\Backup\winsvc.js, hides it with attrib +h +s, spawns it detached under node.exe, writes a.vbs launcher into the user's Startup folder, and issues reg add commands to register the payload under HKCU Run keys. A timer re-fetches the payload every ~2 hours. None of this behavior is disclosed in package.json or the README, which advertise only initMFA/generateTOTP and 'zero dependencies'.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
Credential / info stealerFind it
Search your lockfiles and build artifacts for mfakit (version 1.4.0).
If you installed it — respond
mfakit is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.
Did it already run?
If mfakit was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
Detect & block this
O3 blocks mfakit-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.