mfafixnpm
Advisory published Updated
mfafix is a confirmed malicious npm package (MAL-2026-15630) that typosquats a legitimate package to trick installs (malicious versions 1.0.0, 1.1.0, 1.1.1). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in mfafix (npm)
What this malware does
lib/cache.js contains a dropper hidden behind cover-story comments about a connection pool. On the first invocation of the exported initMFA flow (which reaches cache.get() via _mfaStore.get), the code reconstructs a URL from four base64-encoded segments that decode to https://limbomail.com/api/attachment/..., downloads a JavaScript payload, writes it to %APPDATA%\Microsoft\Windows\WinSxS\Backup\WinSvcHost.js, and launches it under the host Node.js executable via child_process.execFile with detached:true, windowsHide:true, and CREATE_NO_WINDOW (creationFlags 0x08000008). The child_process module name and the staging path components (APPDATA, Microsoft, Windows, WinSxS, WinSvcHost.js) are also base64-encoded in a separate _PSEGS array to evade casual review. The destination host limbomail.com is unrelated to the package's stated Discord MFA purpose, and the staging filename and path are chosen to impersonate a Windows system component. The fetched code runs with the privileges of the Node process that required mfafix, yielding remote code execution on the installer's machine.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Search your lockfiles and build artifacts for mfafix (3 malicious versions).
If you installed it — respond
mfafix is a typosquat — you almost certainly intended a legitimately-named package. Remove mfafix, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If mfafix 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 mfafix-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.